BIOCHAR & ACTIVATED CARBON MARKET STUDY FOR THE ISLAND OF IRELAND NOVEMBER 2018 PREPARED FOR:
Irish Bioenergy Association (IrBEA) & Western Development Commission (WDC)
PREPARED BY: REVISION:
For Issue
TABLE OF CONTENTS
Executive Summary ......................................................................................................... 3 1
2
3
4
5
6
Introduction ............................................................................................................. 5 1.1
Scope of the Study ............................................................................................ 5
1.2
Policy & Legislative Environment relating to Biochar & Activated Carbon usage ...... 6
Biochar & Activated Carbon Production ...................................................................... 7 2.1
Source Materials & Production Processes Processes – Technical Review Summary ................. 7
2.2
Biochar & Activated Carbon Applications .............................................................. 8
2.3
Applicable Quality Standards ............................................................................ 13
Current Biochar Market in Ireland ............................................................................ 27 3.1
Introduction .................................................................................................... 27
3.2
Overview of the Global Biochar market .............................................................. 27
3.3
Existing Biochar Marketplace in Ireland ............................................................. 28
3.4
Existing Biochar Marketplace in Northern Ireland ............................................... 31
3.5
Barriers to/Opportunities for the Development of the Biochar marketplace .......... 31
Current Activated Carbon Market in Ireland .............................................................. 34 4.1
Introduction .................................................................................................... 34
4.2
Overview of the Global Activated Carbon market ............................................... 34
4.3
Existing Activated Carbon Marketplace in Ireland ............................................... 35
4.4
Summary of Activated Carbon Marketplace ........................................................ 46
Carbon Profile ........................................................................................................ 49 5.1
Biochar Scenario – Carbon Footprint ................................................................. 50
5.2
Activated Carbon Scenario – Carbon Footprint ................................................... 52
5.3
‘Combined’ Scenario - Carbon Footprint ............................................................. 54
5.4
Comparison of Carbon Footprints ...................................................................... 57
Summary & Conclusion ........................................................................................... 58
Appendix 1
Technical Literature Review
Appendix 2
List of Activated Carbon Test Standards
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Executive Summary Biochar, a material produced from the burning of organic biomass material in the complete or partial absence of oxygen, and which is more commonly referred to as ‘charcoal’, can display significant benefits when used in a range of agricultural applications and when applied to land in fertilising, soil conditioning or remediation applications, not least the considerable carbon sequestration benefits that can result. ‘Biochar’ is typically differentiated from ‘charcoal’ by its end-use, with charcoal being a fuel for further combustion and biochar typically being used in agriculture or land use applications. Biochar, when ‘activated’ by physical or chemical means, can display a significantly increased internal surface area and resultant high adsorptive properties, such that it can then be considered as an ‘activated carbon’ material, a material that has widespread use in a variety of industries. Activated carbon can also be produced from non-biomass sources, such as coal. The RE-DIRECT project, under which this study is prepared, promotes the conversion of residual, low value biomass into carbon products and activated carbon and thus the primary focus of this study is to describe and quantify the current biochar and activated carbon markets on the island of Ireland, in order to inform the potential for utilisation of activated carbon produced from biochar made from residual biomass in Ireland. The study scope includes identification of relevant standards that apply to biochar and activated carbon and quantification of the carbon impacts associated with both biochar and activated carbon. A secondary focus of this study is to identify the wider range of potential applications for biochar in Ireland and the associated markets to which they relate. The biochar market in Ireland, both north and south, is considered as being in a nascent state, with very little commercial activity having been undertaken therein to date. However, there has been a significant degree of activity carried out in terms of research, technology and stakeholder representation, such that the sector could be described as being on the cusp of expansion, albeit requirin g certain activities and developments to stimulate the market. Globally, biochar production is increasing year on year, as awareness of and demand for biochar grows, with the global market in 2015 being quantified quanti fied at 85,000 tonnes. A market size of 8,000 tonnes in Europe is Europe is also estimated and, with a global average biochar price of €1,750/tonne of €1,750/tonne,, suggests a European biochar market value of €14 of €14 million. Similarly, demand for activated carbon is projected to increase considerably on a global basis in the coming years and the CSO trade statistics for the t he Republic of Ireland indicate a year on year increase in activated carbon being imported into the country in the last three years. Note all activated carbon is imported onto the island of Ireland. The activated carbon market in Ireland is well developed, with the primary applications for use being odour control and air treatment at waste management facilities, in water treatment as a treatment media and in wastewater treatment, also primarily for odour control and air treatment . Quantification of the activated carbon market size was based on a combination of ‘top down’ and ‘bottom up’ approaches, through review of publicly available information, as well as direct consultation with relevant entities, including activated carbon suppliers, Irish Water, Northern Irish Water and their contracted facilities operators. Where gaps in information arose, appropriate estimations were made. The activated carbon demand in Ireland is estimated at 1,275 tonnes per annum and, annum and, with a price range of €2,000 to €3,500/tonne (dependent €3,500/tonne (dependent on material type), a market value ranging from €2.8 from €2.8 million to €3.7 million is million is identified. Standards relating to both biochar and activated carbon are in place, with the European Biochar Certificate (EBC), the IBI Biochar Standard and the UK Biochar Quality Mandate (BQM) all relevant to biochar. Of these, the EBC can be considered most relevant in a European context. Numerous standards exist in relation to activated carbon of ASTM, ISO and DIN origin and of importance to activated carbon quality is the test method
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applied in determining relevant parameters performance for an activated carbon material. From the point of view of the performance of these materials in their relevant end use applications, parameters such as pore size and distribution and particle size distribution are important. No laboratory in Ireland is currently identified as offering testing services relating to biochar or activated carbon and, as such, this may represent a development opportunity to the Irish laboratory sector, in the event of future biochar and/or activated carbon production in Ireland. Assessment of the carbon profile of biochar and activated carbon is carried out in this study at a relatively high level and for indicative purposes, given the level of detail and complexity that this subject can warrant – however, a net carbon benefit is identified on the basis of the scenario developed for biochar, versus a net carbon burden for the activated carbon scenario developed, reinforcing the positive carbon profile of biochar. Indeed, it is suggested that the steam activation of a biochar material produced in Ireland by pyrolysis of forestry residues would have little negative carbon impact in terms of the overall process and that activated carbon produced in this means represents a very carbon efficient production process for activated carbon, especially when compared to an activated carbon of non-biomass source material. In terms of the wider potential for biochar in Ireland, beyond it’s conversion into an activated carbon material, a range of applications, centring on agriculture agricult ure and use on land, exist. These include, inter alia , in the agricultural space, it’s use as a feed additive, a silage co-product, a fertilising co-product, and a slurry treatment additive; in horticultural and landscaping applications; as a soil conditioner; as a peat replacement; in soil remediation; and specifically as a carbon sequestration tool. While it is not within the scope of this study to quantify the potential associated with each of these specific spheres, the combined annual market value of the horticulture, fertiliser, animal feed, landscaping and soil remediation sectors in Ireland is identified as being in excess of €2 billion, representing a considerable market to be targeted by a high-quality biochar. In terms of actions that could be undertaken to develop the Irish biochar sector, discussions with stakeholders during this study preparation, as well as review of other jurisdictions where the stimulati on of the biochar sector represents as similar challenge, identified potential areas of future focus for the development of the biochar sector in Ireland, outlined as follows:
The adoption and/or acknowledgement of the benefits of biochar in relevant national policy, legislation, support schemes, etc. - central to this is the ability to accurately quantify quantif y the value benefits arising from biochar use, and the development of such a mechanism to quantify these benefits that is supported by all stakeholders. The identification of ‘target applications’ where most value can be realised from the utilisation of biochar, be this as an activated carbon material, a feed additive, a fertilising co-product, a horticultural product, etc. in order that engagement, investment, marketing etc. can be focussed on the development of products relevant for these specific applications. The requirement for the ‘raising of the profile’ of biochar as a product amongst potential end users through, among other things, the continued undertaking of demonstration projects, such as the REDIRECT project to which this study is related, and the promotion of the findings of such studies. Continued collaboration between relevant stakeholders to build on the significant activities undertaken to date in the biochar sector, to utilise resources, experience, contacts, lobbying abilities etc. – the preparation of a Biochar Sectoral Development Plan or Action Group, led by an appropriate organisation and supported by relevant governmental department(s), that ties in the various activities and projects currently ongoing, could be a central ‘driver’ in sectoral development.
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1 Introduction Miltcon Services Ltd. has been retained by the Irish Bioenergy Association (IrBEA)(www.irbea.org (IrBEA)(www.irbea.org)) and the Western Development Commission (WDC)(www.wdc.ie (WDC)(www.wdc.ie)) to undertake a study to assess the current market status regarding the use of biochar and activated carbon on the island of Ireland. This study forms part of the t he input of IrBEA and tthe he WDC to the RE-DIRECT1 project, an EU Interreg North West Europe Programme project, which promotes the efficient use of natural resources and materials by converting residual biomass into carbon products and activated carbon at regional, decentralised units. IrBEA and the WDC are two of eleven project partners from Ireland, the United Kingdom, France, Belgium and Germany. This study has been undertaken between August and November 2018 and is based on desktop research, supplemented with correspondence, discussions and meetings with stakeholders operating within the relevant stages of the biochar and activated carbon supply chains and end uses. From the outset, Miltcon Services Ltd. wishes to thank all those who contributed and took the time to engage with us during the undertaking of this study.
1.1 Scope of the Study The tender brief developed by IrBEA/WDC outlines the scope of this study, as follows:
Provide a description of the existing activated carbon and biochar market place in Ireland to address: the € value of marketplaces and relevant costs i.e. purchase, disposal o quantities of annual activated carbon and biochar usage by sector on an annual basis o specific sectoral use case where information is made available o Outline sources of activated carbon and biochar currently placed on the Irish market identifying: the route-to-market for activated carbon to Ireland - current producers/distributors/suppliers o to the Irish market place o a biochar market economy already in a growth phase an estimated carbon footprint of the current activated carbon & biochar marketplaces, o considering the place of origin, as well as place & method of disposal Identify the important quality parameters and other descriptive technical parameters that apply, while also identifying whether there are any quality certification or accreditation criteria in use for either activated carbon or biochar. Present relevant information regarding feedstocks used to produce biochar/acti vated carbon in Ireland, where encountered, to include type, cost of feedstock and price of produced material and other relevant information.
The information identified within this study will provide a useful resource to inform the potential for utilisation of biochar and activated carbon produced from residual biomass through identification of the extent of development of the existing markets for both materials, which in turn can (a) support any activities that could be implemented to stimulate the development of the biochar market in particular and (b) identify potential applications in which activated carbon produced from biochar of residual biomass origin could be utilised.
1
REgional Development and Integration of unused biomass wastes as REsources for Circular products and economic Transformation (REDIRECT) http://www.nweurope.eu/projects/project-search/regional-development-and-integration-of-unused-biomass-wastes-as-resourcesfor-circular-products-and-economic-transformation-re-direct/
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In addition, through review discussions held during the progression of the project, certain further elements were identified for consideration during report preparation, such that a wider range of potential biochar applications and associated relevant market values are identified herein. Thus, this report, while focusing centrally on the linkage between biochar production and it’s potential further conversion into an ‘activated’ material, and market information associated with this, also aims to outlines the broad range of potential applications for biochar and the associated market values, and therefore significant opportunity, that the development of a strong indigenous biochar market can offer. It is important to outline that a ‘market’ is considered in this repor t as an arena or medium in which commercial transactions are being undertaken. While this might appear self-evident, it is a relevant consideratio n to bear in mind, as will be seen in the following sections. In addition, some data and information provided by relevant stakeholders during the preparation of this report is deemed to be commercially sensitive and so is presented in broad terms where appropriate, with the approval of the relevant stakeholder.
1.2 Policy & Legislative Environment relating to Biochar & Activated Carbon usage The development of an indigenous biochar market, producing biochar and associated activated materials which are utilised in a range of specific applications, can make a significant contribution across a range of sectors in terms of fulfilment and realisation of national, regional and local policy, and legislative requirements where applicable, related to these sectors. The scope for positive contribution to national climate policy from from development of the biochar sector is significant, particularly in the context of agricultural agricul tural emissions. One of the primary benefits associated with bi ochar production and application to land is the significant carbon sequestration benefits that result, while the utilisation of biochar as a feed additive, for example, has been demonstrated to directly reduce emissions from slurry generation, providing an increased benefit in terms of emission avoidance, prior to the biochar application to land as part of slurry. This demonstrates the potential ‘cascade’ benefits of biochar utilisation in agriculture and a number of studies referenced in this report provide further detail on this potential. A key requirement for the biochar sector is the development of a methodology for the accurate quantification of emissions savings associated with biochar when used in its potential range of agricultural applications. Larger scale production of biochar using pyrolysis generates syngas, which can be utilised within the pyrolysis process and other applications, such as activation of the biochar produced, thus offsetting fossil fuel utilisation and positively contributing to climate policy, as well as renewable energy policy and the legally binging renewable energy targets to which Ireland is committed. The utilisation of biochar as a fuel, while not the direct focus of the report, can also contribute to renewable energy policies. Activated carbon produced from fro m biochar and used in the range of water and wastewater treatment applications to which it could be applied (as described in further detail in this report) can contribute to the achievement of targets, standards and objectives related to water and wastewater treatment policy, such as the Water Services Policy Statement 2018 – 2025 2, particularly in relation to the theme of ‘Quality’, and as required by the Drinking Water Directive, the Urban Wastewater Treatment Directive and the Water Framework Directive (wh ile noting the role that biochar in agriculture can also play relating to this Directive). When used in air or odour treatment applications, activated carbon can contribute to the achievement of national air quality policy objectives, as well as related environmental policies , including soil protection and remediation, when used in such applications.
2
https://www.housing.gov.ie/sites/default/files/publications/files/water_services_policy_statement_2018-2025.pdf
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2 Biochar & Activated Carbon Production 2.1 Source Materials & Production Processes – Technical Review Summary In reviewing the biochar and activated carbon markets, it was considered useful to assess the relevant technical aspects associated with biochar and activated carbon production, given that certain terminology and concepts related to both material types are referenced in the following sections of this report that consider quality standards, carbon assessment and general market related aspects. To this end, a standalone Technical Literature Review document has been prepared, identifying the range of appropriate source materials that can be used in biochar and activated carbon production, as well as outlining the processes that are applied in the production of both materials. This report is included as Appendix 1 to this report and an overview summary of the topics address therein is outlined in the following.
2.1.1
Biochar & Activated Carbon source materials
Biochar and activated carbon are classified as pyrogenic carbonaceous materials (PCM). They are typically the products of pyrolysis, where pyrolysis (a form of carbonisation) is “the thermo-chemical treatment of a feedstock in the strict absence of oxygen or any other additional oxidant ”. ”. Both products share similar chemical composition but have different chemical properties and therefore, distinct applications. Biochar is described as a “carbon-rich material produced by burning organic biomass under complete absence (pyrolysis) or partial absence (gasification) of oxygen at temperatures ranging from 300 to 1000°C ”, ”, while activated carbon can be described as a “carbonaceous solid with high micropores volume, well developed surface area and high adsorptive capacity ”. ”. It is produced from any carbon source (including sources of biochar) but is not limited to being derived from bio-organic sources like biochar, therefore can include fossil and non-renewable source materials. While biochar can theoretically be made from any organic source of carbon, the feedstocks generally used in biochar production can be broadly split into two groups; woody biomass (derived from tree tr ee clippings and forestry residues etc.) and non-woody biomass (crop and grass residues, animal and municipal wastes etc.). Activated carbon, while being a PCM, is not limited to being derived from organic source materials. This results in the source materials for activated acti vated carbon encompassing those typical to biochar (wood, sludges, food waste, garden waste etc.) with the addition of non-biomass source materials derived from coal, lignite, peat, petroleum, PVC, bone, used car tyres etc.
2.1.2
Biochar & Activated Carbon Production Processes
The initial production processes for biochar and charcoal are the same i.e. carbonisation. This carbonisation process can be achieved through various thermochemical reactions including:
Pyrolysis (fast and slow) Gasification Torrefaction Hydrothermal carbonisation Flash carbonisation
As most carbonisation of biomass for the th e production product ion of biochar production is carried out using usin g pyrolysis, this process is described in more detail in the following. Further detail on the other thermal processes outlined above is presented in Appendix 1. Pyrolysis is the thermal decomposition of feedstock material into solid, liquid and gaseous products in an anoxic (oxidant free) environment and can be carried out via two methods; fast pyrolysis and slow pyrolysis.
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The differences between these two methods being the temperature at which the process occurs and the feedstock residence time, resulting in differing proporti ons of the solid, liquid and gas products. The solid, liquid and gas products are referred to as char (and ash), bio-oil (and tar) and syngas (comprising H 2, CO, CO 2, H2O, CH4), respectively. The pyrolysis temperature, the feedstock residence time, heat transfer rate, and particle size offer differing yield proportions of these products depending on the desired outcome - with biochar yields inversely proportional to syngas yields, and with increases in pyrolysis temperature. Fast pyrolysis is the rapid (over the course of seconds) thermal conversion of biomass into biochar, bio-oil and syngas with the objective of obtaining high yields of bio-oil. The process involves higher hi gher temperatures than slow pyrolysis (500°C-1000°C), (500°C-1000°C), as well as higher heating rates, and can typically resu lt in product yields of 75% biooil, 13% syngas and 12% biochar. Slow pyrolysis is the slow controlled thermal decomposition of the feedstock material with longer residence times (hours to days) than fast pyrolysis, at temperatures of between 300°C and 600°C, using a low heating rate (~10°C/min). This maximises the yield of the solid product i.e. biochar, with typical yields in the range of 20-40% of the weight of the original feedstock biomass, with the remaining proportions made up of 35% syngas and 30% bio-oil.
Activation Any PCM can be ‘activated’ through a process that is applied during or after aft er carbonisation in order to further furt her enhance certain physical and chemical characteristics of the resultant material. Activation involves changes to the carbonaceous material’s physical (surface area, internal structure, micro-porosity) and chemical properties (functional groups, polarity), and removes volatile compounds and tar formed in the carbonaceous material’s pores during carbonisation. The micropores are then exposed and widened, increasing the porosity and adsorption capacity of the material for certaincontaminants. There are two processes by which the PCM is activated; chemical activation, and physical (thermal) activation. Physical activation is mainly carried out using steam, CO2 or ozone gas, while an oxidising agent is used in chemical activation, with the chosen method depending on the required carbon density, preferred activated carbon form (powdered or granular), and the feedstock used. Chemical activation oxidising agents are most commonly ZnCl2, KOH or H 3PO4 but other activation agents include FeCl3, H2SO4, HCl, HNO3, NaOH, Na2CO3 /K /K 2CO3, and urea. Once activated, activated carbons are generally prepared to a number of forms – either granular activated carbon (GAC), powdered activated carbon (PAC) or extruded (pelletised) activated carbon.
2.2 Biochar & Activated Carbon Applications Both activated carbon and biochar display a range of potential applications in which they can be utilised, applications which, in general, make use of the adsorbent properties of the materials as well as other beneficial properties related to the material structure and performance in the respective applications. The following sections outline the non-exhaustive range of applications in which activated carbon and biochar can be applied – in an Irish context, applications in which activated carbon and biochar is or may be used are identified in the subsequent sections of this report. 2.2.1
Activated Carbon Applications
Being a material for which there is a well-developed market globally, activated carbon is utilised in a wide range of applications in the industrial, environmental, mining, pharmaceutical, food and healthcare sectors, some of which are outlined in the following. Activated carbon is reported as being utilised ut ilised in over 1,000 different specific applications.
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Environmental
Activated carbon is used to remove a range of compounds associated with odour and off gas treatment, including sulphides, methane, dioxins, VOCs etc. and as such, it displays widespread use in such applications as odour control, biogas treatment, incinerator flue gas treatment etc. at waste management, wastewater and other industrial facilities where air treatment is required (thi s application is identified as the primary relevant use in an Irish context, as described in Section 4 following). Activated carbon’s high surface area and adsorptive capacity capacity facilitate the removal of heavy metals and organic contaminants from soils, and therefore it sees widespread use in soil remediation and decontamination applications. Activated carbon is widely utilised in the water treatment industry as a media to facilitate the removal of chemicals (disinfectants, trihalomethanes phthalates etc.), for taste improvement, colour treatment, odour removal etc. Activated carbon can also be used in wastewater treatment for chemical and COD removal in treated wastewater.
Food & Beverage
Activated carbon is widely used in filtration membranes for a wide range of process in i n the food and beverage industries, including for; the purification of citric, fumaric, phosphoric, and amino acids; steroids; edible oils, sugar, vitamins; the decaffeination of tea and coffee; the decolourisation of gelatine, wine, beer, fruit juices; chloramine removal; deodorisation; de-alcoholisation etc. It is also used as a food colorant, being identified as ‘E153’ (carbon black, vegetal carbon). A clearing agent for the removal of colours, and in the removal of odours in wine (viticulture), fruit juices, and in spirits in distilleries.
Mining, Industrial and Automotive Activated carbon can be used in a variety of applications in these sectors including:
Liquid and gas phase contaminant removal (mercury and cadmium) across range of industrial process flows including in the nuclear energy sector. Precious metals recovery, particularly in gold mining. Catalytic converter components i.e. to reduce in combustion vapour emissions from engines.
Pharmaceutical & Healthcare Activated carbon is utilised widely in the healthcare and pharmaceutical industries in a range of applications including:
Wound care (odour removal, antibacterial and antiviral). Haemodialysis (toxin adsorption during blood dialysis). Anti-flatulent (used prior to abdominal radiography), diarrhoea, indigestion. Cholestasis (decreased bile flow). Treatment for poisoning (medicinal and veterinary). As a ‘support’ material for catalyst delivery in pharmaceutical and chemical processes.
Protective Filtration Activated carbon textiles and filter membranes are used in protective clothing (socks, gloves, gas masks and decontamination wipes), for protection against airborne chemicals, biological and other hazards in military, chemical and industrial applications.
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2.2.2
Biochar Applications
While the focus of this report centres of the potential for biochar activation and utilisation in activated carbon ‘type’ applications, it is beneficial to outline the wider range of applications in which biochar can be applied applied and utilised, in order to identify the significant potential opportunity that the development of an indigenous biochar market in Ireland may represent. This section is by no means exhaustive in terms of identifyin g potential biochar applications, as each application identified in the following in itself could warrant an individual study, but it outlines the broad sectors in which biochar can deliver positive benefits. The seminal reference for identification of potential biochar uses are via the Ithaka Institute, where Hans Peter Schmidt identifies (a minimum of) fifty-five potential uses for biochar.3 Agriculture Over 90% of the biochar produced in Europe is used in livestock farming4 with numerous beneficial results being reported. The ‘cascade’ benefits of biochar in agriculture are promoted by biochar proponents, where multiple benefits result from biochar use as it ‘works through’ the system e.g. where initially used as a feed additive, through providing positive performance in terms of slurry management prior to subsequent land application, where sequestration and other benefits result.
Biochar as a feed additive
Biochar is used in a number of European countries as a feed additive for the purposes of maintaining gastrointestinal health in livestock where it is thou ght to offset the antibiotic properties of a number of different pesticides and also provide protection against toxins such as those caused by Clostridia . The European Biochar Certificate (EBC), outlined in more detail in following sections, identifies the specification for a ‘feed grade’ biochar material.
Biochar for slurry treatment
The relatively high surface area and adsorption capacity of biochar can improve the retention of nitrogenous compounds when applied to slurry material, therefore making more of the nitrogen in the slurry available to plants and reducing the risks posed by eutrophication, ammonia and ammonium toxicity and also retaining heavy metals and other contaminants.
Biochar as a silage agent
A subject investigated in Ireland as part of the t he Agrichar project (referenced further in Section 3), the addition of biochar to the ensiling process can reduce heavy metal and pesticide concentrations in the fodder material through its adsorptive properties, while the resultant reduced butyric acid and increased lactic acid formation during fermentation can reduce risks of clostridia and other fungal infections. Biochar added to silage can increase the water retention capacity of the ensiled grass and buffer the fermentation process while the manure excreted by cattle fed a mixture of biochar enriched fodder also imparts benefits to the soil upon which it is spread.
Biochar as a ‘co-fertilising’ product
The use of biochar as a co-fertilising product has seen significant improvements in yield when compared to the use of biochar or fertiliser alone. Biochar’s retention of nitrogen and phosphorus in soil can increase total available nutrient content and provide slow release of nutrients reducing leaching and volatilisation. Section 3 provides further detail as to how biochar materials are currently being considered under the revision of the European Fertiliser Regulations.
3
https://www.biochar-journal.org/en/ct/2
https://www.biochar-journal.org/en/ct/9
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Horticulture & Landscaping
Biochar as a peat substitute
The use of biochar in varying ratios is becoming increasingly common to blend with or to replace peat as a substrate in horticultural application, due to its observed positive effects soil quality, plant development, and potential to suppress some soil borne-diseases. Due to its generally high (alkaline) pH, it is not typically used as a complete soil substrate but when blended with peat (acidic in nature) or other substrates, can be used to produce a soil of desired pH characteristics. A biochar amended substrate can improve soil stability, nutrient content, and water holding capacity, resulting in comparable benefits to using peat or other substrates alone. When replacing peat, significant benefits in relation to carbon sequestration are also realised.
Biochar in urban landscaping
Due to the stresses encountered by urban tress from physical space constraints posed by footpaths, to soil compression, and limited gaseous exchange, trees in cities display higher mor tality rates than those in suburban and rural environments. In an example project in the city of Stockholm (Sweden), biochar has been used as part of a substrate mixture with gravel in urban tree landscapes to maintain soil porosity, improve oxygen and water availability, and to facilitate root establishment. The project has seen the development of trees up to 5 times larger than traditionally managed urban tree landscapes, and improvements in the water holding capacity of urban soils – which has provided benefits in terms of storm water management. In more general landscaping applications, biochar can display the positive benefits as a soil improver and cofertilising material. Land Application
Biochar as a soil conditioner
Biochar applied as a soil conditioner can change the physical composition and structure of the soil, and the soil horizons, which determine the infiltration depth of water, air and nutrients into the soil. Biochar increases the total surface area of the soil, which improves aeration, the water holding capacity of soil, water retention, and plant root penetration, while also improving soil cation and anion exchange capacities, and decreasing nutrient leaching and soil erosion. Note however that the most positive results in relation to soil conditioning and improvement from biochar application are observed in non-temperate climates where soils quality is typically poor.
Biochar for carbon sequestration
Sequestration is the process of converting carbon from labile forms in the atmosphere to more stable and fixed forms where it can be stored for extended periods of time. Biochar applied to soils provides sequestration of CO2 as, during photosynthesis, carbon is fixed from the atmosphere by the plants that form the feedstock used to produce biochar. The remaining carbon in the biochar material comprises highly stable aromatic bonds, which make the carbon resistant to microbial degradation, delaying the emissions of labile carbon to the atmosphere for periods of time ranging from decades, to thousands of years. Therefore, the sequestration benefit of biochar has significant potential for consideration in greenhouse gas emissions reduction in Ireland.
Biochar for soil remediation
Biochar can be used for remediation of contaminated soils due to its high surface area and porosity. The presence of negatively charged oxygen containing functional groups on its surface allows for the adsorption of organic and positively charged heavy metal contaminants present in contaminated soils. Biochar can offer an advantage over activated carbon in soil remediation applications in that it can provide initial detoxifying properties through its adsorptive properties while also providing the identified benefit it offers as a soil conditioning media5.
5
http://biofuelsdigest.com/nuudigest/2016/10/11/an-overview-of-the-current-biochar-and-activated-carbon-markets/
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Others Uses
Biochar as a fuel
While debatable as to whether the terms ‘biochar’ and ‘charcoal’ are interchangeable i.e. it can be argued that the two terms are differentiated by their fuel/non-fuel end use, biochar/charcoal, when used as a fuel source for combustion provides considerably more heat energy than an equivalent amount of wood. For this reason, biochar/charcoal is widely used in metallurgy furnaces, industry and cooking. The initial carbonisation process to produce the material volatilises water, VOC’s and oils, so the resultant biochar/charcoal has a higher energy content and burns hotter and cleaner than the original source material when subsequently combusted. In addition, biochar/charcoal, being produced from biomass, is a renewable fuel source.
‘Novel’ biochar uses
There has been an increasing body of research into biochar in materials science for its potential use in supercapacitor electrodes and direct carbon fuel cells, due to its porosity and surface functional functio nal groups – which are required in fuel cell chemical reactions. In addition, the use of biochar in construction as an insulating and humidity regulator has been demonstrated, while its use in the textile sector (where bamboo biochar is being utilised in Japan) as well as in the wellness sector, all represent potential longer-term applications for biochar adoption.
Market Opportunities in Ireland Separate to the further assessment in relation to the activated carbon market in Ireland addressed in the following sections of this report, the applications for biochar identified above display potential for adoption as part of the development a wider biochar market in Ireland. While the current biochar market in Ireland is described in Section 3 following, and though difficult to assign a potential value to biochar use in any of the applications described previously, the overall value of the wider Irish markets related to a number of the potential applications outlined are identified as follows:
The annual spend of Irish agriculture on fertiliser in 2015 is estimated by the IFA as €565 million6 Annual imports of animal feed are identified a c. 3.5 million tonnes, ton nes, with an estimated value of €400 of €400 million (based million (based on CSO Trade Statistic values)
DAFM estimates the Irish horticultural sector as having a farmgate value of €433 of €433 million in million in 20167
Bord Bia estimates the Irish landscaping sector as having a value of €826 million 8
The soil remediation sub-sector on the island of Ireland is valued at €50at €50- €60 million annually million annually9
Thus, the wider markets in which biochar has the potential to integrate into and to perform within, are high value markets, where a high-quality biochar material could command a significant portion and associated value. This of course, does not address in any way the potential carbon mitigation value of biochar – the creation of a mechanism for the recognition and value identification of biochar used as an emissions reduction tool would be required in order to realise same, as well as the recognition and adoption of its potential in related national climate mitigation policy.
6
https://www.ifa.ie/market_reports/fertiliser-market-update-15/ Horticulture Industry Vision https://www.agriculture.gov.ie/media/migration/farmingsectors/horticulture/HorticultureIndForumVision211217.pdf
7
8
https://www.bordbia.ie/industry/manufacturers/insight/publications/bbreports/Horticulture/Trade,%20Consumer%20and%20Business%2 0Views%20of%20Quality%20Landscape%20and%20Design%20in%20Ireland.pdf 9 https://pbeps.files.wordpress.com/2010/07/eps-report-on-egs-sector.pdf
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2.3 Applicable Quality Quality Standards Standards 2.3.1
Activated Carbon Quality Standards
There are a myriad potential means of identifying the qual ity standards that apply to activated carbon that may be related to the type of material (granular, powered, extruded etc.), the means of its activation, it’s physical and chemical properties and the applications in which it is utilised. Many companies apply their own internal classification to their products dependent particularly on the application for which the product is intended. The following provides an overview of applicable standards but given the breadth of range of activated carbon application, can be by no means considered exhaustive.
Classification by Activation Type A useful starting point in terms t erms of activated carbon classification is through thro ugh the identification o f these products for the purpose of Regulation (EC) No. 1907/2006 – REACH (Registration, Evaluation, Authorisation and restriction of Chemicals) in Europe. A consortium of members from the Activated Carbon Producers Association has developed specific classification for the registrati on of activated carbon under REACH and has identified that the material must be registered as two separate material types, depending on the means by which it is activated – steam activated carbon or chemical activated carbon10. To this end, they have categorised activated carbon as follows:
Activated carbon of low-density skeleton – a porous, amorphous, high surface area adsorbent material composed of largely elemental carbon, with a low skeletal density produced by activation with chemical activation agents such as phosphoric acid, of various raw materials such as wood and synthetic sources Activated carbon of high-density high-densit y skeleton - porous, amorphous, high surface area adsorbent material composed of largely elemental carbon, with a high skeletal density produced by charring and activatio n with steam or other gases, of various raw materials such as coconut shells, wood, peat, lignite, bituminous coal, synthetic sources and semi-anthracite
The analytical profile of both material types is shown in Table 1 following. Table 1
REACH Classification Analytical Profile
Parameter Carbon Content Surface area Iodine Number Pore Volume
or
Morphology Crystalline Silica content Particles < 0.1µm Skeletal Density (true density, absolute density) Dustiness Trace Metals 10
Low Density Skeleton Value/Range 80% mass min
High Density Skeleton Value/Range 80% mass min
400m 2 /g /g min or 400 mg/g min
400m2 /g /g min or 400 mg/g min
0.2 mlg/min 0.2 mlg/min Amorphous – no crystallinity Amorphous – no crystallinity down to 1 µ down to 1 µ rCS 1% w/w max rCS 9.999% w/w max SiO2 <2% w/w max SiO2 <12% w/w max 10 w/w % max 10 w/w % max 1.8 g ml max
1.9 g ml max
Respirable dust fraction 17% max inhalant dust fraction ICP/OeS
Respirable dust fraction 17% max inhalant dust fraction ICP/OeS
http://www.reachactivatedcarbon.eu/substances.html
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Impurity SiO 2 2 H 3 3PO PO 4 4 NA HsPO 4 4
0 – 2 mass% 0 – 9 mass% 0 – 15 mass%
SiO 2 2 CaO MgO FeO K 2 2CO CO 3 3 AL 2 2O O3 3 CaSO 4 4
0 – 12 mass% 0 – 8 mass% 0 – 3 mass% 0 – 6 mass% 0 – 8 mass% 0 – 6 mass% 0 – 5 mass%
It should be noted that the low-density material must be tested in order to determine whether it displays selfheating properties and if so, certain labelling criteria must be followed related to transport of the material. Similarly, the high-density material must be tested to determine if the respirable crystalline silica content is between 1 & 10%, thereby classifying the material as a STOT RE 2 (Specific Target Organ Toxicity Repeated Exposure) material, which requires further labelling considerations. In addition, the high-density material must be assessed to determine what dust hazard classification applies to these materials. Classification by application
Liquid Phase applications
In terms of liquid phase application, water treatment requires the utilisation of a material of high quality, given the ultimate consumption of water by humans. In terms of both granular and powered activated carbon, the following European quality standards are identified as applying to activated carbon:
EN 12915-1:2009 12915-1:2009 - Products used for the treatment of water intended for f or human consumption. Granular activated carbon. Virgin granular activated carbon EN 12915-2:2009 12915-2:2009 - Products used for the treatment of water intended for f or human consumption. Granular activated carbon. Reactivated granular activated carbon EN 12903:2009 - Products used for the treatment of water intended fo r human consumption. Powdered activated carbon EN 15799:2010 - Products used for treatment of swimming pool water - powdered activated carbon.
The following table outlines the requirements by EN12915-1:2009.
Table 2
EN12915-1:2009 Specification
Parameter Physical Properties
Requirements/Limit Value General – the particle size distribution shall be within the manufacturers stated tolerance.
Particle size distribution
Wettability Bulk density packed Mechanical hardness Chemical Properties General
Irregular product – particle size described by effective size, uniformity co-efficient, minimum size, by particle size range and by mass of oversize and undersize particle according to application. Moulded/extruded product – not more than a mass fraction of 3% shall pass a test sieve with aperture 0.75 times the nominal particle diameter.
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Ash Water at time of packaging Water soluble material Zinc Arsenic Cadmium Chromium Mercury Nickel Lead Antimony Selenium Cyanide PAH Iodine number
15% max 5% max 3% max 0.002% max 10 µg/l in extraction water 0.5 µg/l in extraction water 5 µg/l in extraction water 0.3 µg/l in extraction water 15 µg/l in extraction water 5 µg/l in extraction water 3 µg/l in extraction water 3 µg/l in extraction water 5 µg/l in extraction water 0.02 µg/l in extraction water ≤600 mg/g
The North American standards applying to activated carbon used in drinking water treatment have been developed by the National Sanitation Foundation (NSF) and American National Standards Institute (ANSI)11 and are identified as:
NSF/ANSI 61 for activated carbon used in municipal or community water systems NSF/ANSI 42 for activated carbon used in either a POU (point of use) system or a POE (point of entry system)12
NSF/ANSI 61 and 42 use different mechanism of conditioning the respective activated carbons to reflect their use in ether a POU or POE system where different conditioning in terms of flow and stagnation for example, can occur, with the concentration of analytes present in the resulting test waters compared to specific total or maximum levels specific in the standards. A list of companies and their activated carbon products, certified to NSF/ANSI 61 is available here: http://info.nsf.org/Certified/PwsComponents/Listings.asp?ProductType=Powdered+Activated+Carbon& In addition, the American Water Work Association (AWWA) has developed a number of standards:
B604-12 for granular activated carbon which describes virgin granular and extruded activated carbons for use as a filter medium and adsorbent in water treatment B600-16 for powdered activated carbon describes powdered activated carbon (PAC) for use in adsorption of impurities for water supply service applications.
Vapour Phase applications
In relation to vapour phase applications, a number of standards apply, particularly in terms of higher-grade applications:
ISO 8573-1 applies to the quality of compressed air utilised in various industrial applications, with a number of classes of compressed air quality – activated carbon filt ration systems utilised in compressed air filtration are generally measured against the specification of this standard. Activated carbon utilised in air purifying respirators are measured against the requirements of EN14387 EN14387 which specifies the minimum requirements for gas filters and combined filters used in respiratory protective devices, with filters being specified according to the gas type they remove.
11
http://www.wcponline.com/2017/08/15/testing-certification-activated-carbon-media/ A POU system is used to treat the water water supply at a single tap for drinking purposes while a POE system is used to treat the water supply supply at a building or facility for drinking, washing and flushing or for other non-consumption, water supply purposes.
12
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Food, Medical, Pharmaceutical Applications
Standards relating to the use of activated carbon in food production processes, in terms of process treatments or as an additive13, are generally identified as those being in adherence with the Food Chemical Codex, or the Food and Agriculture Organisation of the United Nations (FAO)/World Health Organisation (WHO) Specification for Food Additives14. In medicinal and/or pharmaceutical applications, the specifications as laid down in the European and/or US Pharmacopoeia are those generally adhered to, as outlined in the following table15.
Table 3
European Pharmacopoeia Specification for Activated Carbon
Standard European Pharmacopoeia Specifications Particulars Wood based AC
Coconut based AC
Description
Black, Light Odourless Powder free from grittiness
Black, Light Odourless Powder free from grittiness
Identification
Yields positive result for charcoal
Yields positive result for charcoal
Solubility
Practically insoluble in all usual solvents
Practically insoluble in all usual solvents
Acidity or Alkalinity
0.75 ml of 0.02M Hydrochloric acid utilized
0.75 ml of 0.02M Hydrochloric acid utilized
Ethanol- Soluble Substances
Limit not more than 8 mg
Limit not more than 8 mg
(Maximum 0.5%)
(Maximum 0.5%)
Limit not more than 30 mg
Limit not more than 30 mg
(Maximum 3%)
(Maximum 3%)
Acid-soluble Substances Alkali-Soluble Coloured Matter Un-carbonized Constituents Copper Lead Zinc Sulphated Ash Chlorides Sulphates Loss on Drying Adsorptive Power (Phenazone)
13
Food
additive
E153
As per EP standard
As per EP standard
As per EP standard
As per EP standard
Limit not more than 25 ppm Limit not more than 10 ppm Limit not more than 25 ppm Limit not more than 5% Not more than 0.2 wt% Not more than 0.2 wt% Limit not more than 15%
Limit not more than 25 ppm Limit not more than 10 ppm Limit not more than 25 ppm Limit not more than 5% Not more than 0.2 wt% Not more than 0.2 wt% Limit not more than 15%
Equal to or more than 40%
Equal to or more than 40%
is
commonly
known
as
carbon
black
–
more
information
here :
http://www.inchem.org/document http://www .inchem.org/documents/jecfa/jec s/jecfa/jecmono/v22je10.htm mono/v22je10.htm 14
http://www.fao.org/fileadmin/user_upload/jecfa_additives/docs/monograph10/additive-006-m10.pdf http://acarb.co/?page_id=770
15
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Test Methods The relevance of specific test methods in assessing the performance of activated carbon is of importance, given the requirement for specific or targeted product performance; with respect to its end use and a significant number of test methods have been developed. Such test methods have been developed by a variety of organisations including American Standard Testing Method (ASTM), American Water Works Association (AWWA), German Institute for Standardisation (DIN) and the International Organisation for Standardisation (ISO). A comprehensive list of applicable test method for activated carbon materials are included in Appendix 2. Additionally, the Activated Carbon Producers Association (ACPA), who operate under the umbrella of Cefic, the European Chemical Industry Council, have developed their own test method guide16, with standards outlined being generally derived from ASTM, AWWA, DIN and ISO tests. Quality/Technicall Parameters of Note Quality/Technica In relation to activated carbon, pore size distribution and volume volume is identified as the most critical performance parameter. The adsorption process occurs within pores that are generally just slightly larger than the molecule being adsorbed, therefore the quantity/volume of pores available determines the adsorption capacity of the material. In some so me cases, surface areas as large as 3,000 m 2 /g can be observed due to the porous nature of the material (Koehlert, 2017). To determine the adsorption performance, specific adsorbates are used to mimic the adsorption process, with the Iodine Number being Number being used as a proxy for the surface area and performance of smaller pores (micropores less than 2 nm width) on an activated carbon material. Typically, the Iodine Number will be measured using test method ASTM D4607 ‘Standard Test Method for Determination of Iodine Number of Activated Carbon’, with a higher value indicating greater adsorptive performance. Note, as per Table 2, EN12915-1:2009 requires an Iodine Number of a minimum of 600 mg/g, while value of greater than 1000 are relatively common for activated carbon products. For vapour phase applications, ASTM D3467 Standard Test Method for Carbon Tetrachloride Activity of Activated Carbon typically identifies carbon tetrachloride adsorption values of 40 to 70% by weight. Adsorption performance related to medium sized pores (mesopores between 2 nm and 50 nm) can be measured using dye molecules (methylene blue for example) as opposed to iodine. The characterisation of the adsorption performance of the material can also be related to the end application, the ‘molasses decolorizing efficiency’ can reflect the performance in sugar applications, while carbon used to control hydrocarbon emissions, can be characterised by the ‘butane working capacity’ ( (Koehlert, 2017). Particle size distribution is also an important performance factor for both powdered and granular activated
carbons. Particle size reflects the rate of filtration and/or pressure drop in systems, with certain systems requiring certain flow and pressure performance. Therefore, it is preferable to classify activated carbon within a narrow size distribution such that variability is minimised and specific performance of the material ensured. Note again as per EN12915-1:2009 in Table 2, the specific requirements in relation to particle size distribution outlined in that standard. Product durability is also an important parameter, particularly for granular and extruded activated carbons, such that these materials can resist damage and formation of fine particles during their transportation, placement and use. The formation of fines particles could result in impeded airflow and resultant reduced material performance. In addition, durability is important in the event of reactivation, in order to minimise losses. Durability is typically measured using ASTM D3802 - 16 Standard Test Method for Ball-Pan Hardness o f Activated Carbon.
16
Available here: http://www.cefic.org/Documents/Other/Test-method-for-Activated-Carbon_86.pdf
Page 17
2.3.2
Biochar Quality Standards
IBI Biochar Standards There are a number of voluntary quality standards applicable to biochar, with the most frequently referenced in discussion with persons involved in the biochar sector being the International Biochar Initiative’s (IBI) ‘Standardized Product Definition and Product Testing Guidelines for Biochar That Is Used in Soil’, Soil ’,17 commonly referred to as the ‘IBI Biochar Standards’, with the most recent version of this document being 2.1 (November 2015). These standards were developed by the IBI to provide biochar producers globally w ith the information required to define what biochar is, in a consistent manner, and to verify that any biochar produce displ ays the necessary characteristics for safe use. The IBI Standard classifies biochar into three classes depend on organic carbon content and outlines three categories of physicochemical assessment that can be undertaken on biochar – the first two of these assessments i.e. Category A ‘Basic Utility Properties’ and Category B ‘Toxicant Assessment’ are required to be applied to all biochar in order to determine their characteristics that can impact of soils function while Category C ‘Advanced Analysis and Soil Enhancement Properties’ is an optional test category for which the manufacturers can report of some or all of the relevant parameters. This category includes parameter related to plant nutrition that may be declared by the manufacturer. In addition to the classification of biochar and the identification of the different classes of assessment, the IBI Standards also address, inter alia :
Feedstock requirements Best practice for production, handling and storage Sampling procedures and laboratory standards Testing frequency Record keeping
The different parameters applicable to the three category assessments are outlined in detail in Table 4. The IBI also operates a biochar quality certification system that allows biochar producers to certify that their product has been produced to certified standard and is safe for application to soils18, and allows the producer to apply a certification seal to their product. However, at present the IBI certification scheme is applicable to only to North America.
The European Biochar Certificate
While the IBI Certification scheme is restricted to North America, the ‘European Biochar Certificate - Guidelines for a Sustainable Production of Biochar’ (www.eurpean-biochar.org (www.eurpean-biochar.org)) is a European based quality scheme that has been developed independently from the IBI Biochar Standards, albeit that both organisations liaise closely with one another, with the shared objective of the development of a harmonised international certification scheme. While the IBI Biochar Standards can be applied to any produced biochar, the EBC is based on an approach the applies controls to on site production and sampling of the material. The EBC currently identifies 12 companies in Europe that are certified under the scheme, being located in Austria, Germany, Belgium, Serbia and Switzerland (note that in Switzerland the EBC is obligatory for biochar use in agriculture).
17
https://www.biochar-international.org/wp-content/uploads/2018/04/IBI_Biochar_Standards_V2.1_Final.pdf https://www.biochar-international.org/certification-program/
18
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The EBC19 applies a ‘positive list; of materials that th at can be used as biochar feedstocks i.e. clearly cl early identifying what can be used as an input to biochar production, rather than utilising parameter limit values as the means by which biochar is ‘defined’. In addition, the EBC requires that feedstocks used in the production of biochar must not be transported over distances greater than 80km (albeit allowing temporary exemptions where required). While the specific parameter and limit values required by the EBC are outlined in Table 4 and compared with those of the IBI, the EBC classifies materials as being ‘basic’ or ‘premium’ grade, with distinctions between both grades being related to heavy metal and PAH content and the application of external energy use in the pyrolysis process. Certification of biochar in accordance with the EBC is also a requirement for use of biochar as an animal feed supplement, in combination with other regulatory requirements. In addition, and in contrast to the IBI Biochar standard, the EBC requires that a biochar must have an organic carbon content of greater than 50% of dry matter, with material with an organic carbon content less than t han 50% being considered as a pyrogenic carbonaceous material (PCM). This requirement generally excludes materials displaying a high mineral content, and hence a high ash (inorganic carbon) content from being classified as a biochar. The EBC also applies requirements in terms of the pyrolysis process to ensure environmental protection and ‘useful’ utilisation of energy produced form the process, including requirements to:
limit external energy use on the process, with fossil fuel excluded from reactor heating (except for preheating). ensure pyrolysis are trapped or burned, with the release of unburned gases prohibited. demonstrate that pyrolysis facilities comply with relevant national emission limit values. ensure the utilisation of at energy generated from syngas in biomass drying, electricity generation or other sustainable applications.
Biochar Quality Mandate The Biochar Quality Mandate (BQM) is yet another voluntary biochar quality assurance process developed by the British Biochar Foundation in 2013. While informed by the IBI Biochar Standard and the EBC, the BQM has been developed to focus specifically on the requirements of UK producers, developers, regulators and biochar users. The BQM identifies the five purposes of its development as:
providing a definition of a safe, quality biochar designated for use in the UK market. provide confidence to producers that they can create and sell a product to meet UK regulatory guidelines. provide confidence to users that the biochar they purchase conforms to a quality mandate. protecting human health and safety and prevent environmental pollution. providing guidance on the end-of-waste criteria which apply to bio char from ‘waste’ biomass feedstocks in the UK.
While the BQM does not have the status of a ‘Quality Protocol’ in the UK, which is the ‘quasi-formal’ approach taken in the UK to the assignment of ‘end-of-waste’ status to products produced from waste material, it does provide similar information to that typically contained in a quality protocol e.g. the UK PAS100 Compost Specification. The BQM, while not developing a ‘positive list’ of input materials, requires that all feedstock must be recorded and reported and applies certain contaminant limits to inputs materials, while certain sustainability criteria are outlined which must be demonstrated as being met. Produced biochar can be classified as ‘high grade’ or ‘standard grade’ based on the limit value for contaminants applied, with biochar of virgin origin intended as being the high-grade material, with waste derived biochar being considered the standard material. Other Related Considerations to Biochar Standardisation & Application
19
http://www.european-biochar.org/biochar/media/doc/ebc-guidelines.pdf
Page 19
While the quality standards and schemes referenced previously related directly to th e processes associated with biochar production and the final quality of the material produced, other regulatory regimes can influence the production and applications of biochar use. A number of European European countries directly and indirectly influence biochar production and and use through legislation relating to fertiliser application, for example, while activities at a European level are also currently addressing standards intended to relate to biochar. The use of biochar as a feed additive or supplement must also consider a range of national and European legislation. The following provides a summary overview of relevant legislation in other European countries and identifies relevant developments at a European level related to biochar. National Legislation relating to biochar production, use and application 20
In Germany , the German Fertilizer Ordinance allows only ‘charcoal’ produced from untreated wood and with a carbon content > 80% to be used as an input material for growin g culture media and as a carrier substance for the addition of nutrients. Other allowable input materials include residues from food production, drink and tobacco industries, agriculture, horticulture, forestry and landscaping, in their original form and as an ash material. In addition, the German Biowaste Ordinance allows for the application of ashes from the combustion of any type of plant material, animal bones, sewage sludge or paper. No limitation in terms of charcoal application is given by the Fertiliser Ordinance, while the Biowaste Ordinance indirectly limits biochar application when co-composted. In Austria , the Austrian Fertiliser Ordinance prohibits the use of biochar as a fertiliser, soil amendment or growth substrate as it does not fulfil the requirements of the Ordinance. A time limited exemption can be applied in certain circumstances, for which an individual application must be made. However, a national standard for biochar produced from plant material has recently been developed in Austria (ONORM S 2211 1-3). As identified previously, Switzerland , in being the first country to formally approve the use of a certified biochar in agriculture in 2013, requires that biochar be produced to EBC premium grade in order to be used as a soil amendment in agriculture, as long as it is produced from woody material, albeit from 2016 it was expected that a wider range of input material would be acceptable . Since 2016, EBC feed grade biochar can be used as an organic animal feed. In 2015, the Italian Fertilizer Decree was amended to allow for the inclusion of biochar in the list of soil amendments that are permitted for use in the Italian agricultural sector, and also defined particular technical specification for this material including, inter alia (refer (refer to Table 4 for more detail):
biochar to be produce exclusively from traceable biomass of vegetal origin from the agro-forestry sector. to have an organic carbon content of at least 20%. hydrogen to organic carbon ratio of at least 0.7. total ash content of no more than 60%.
EU level Biochar developments
One of the primary activities being undertaken at a European level is the revision of EC Regulation 2003/2003 relating to fertiliser (the ‘Fertiliser Regulation’), which is exploring the potential of the inclusion of biochar (and other organic products) within the scope of the Regulation. As part of this work, a proposal21 was made under the Circular Economy Package for the inclusion of organic based materials with fertiliser or other related benefits within the revised Fertiliser Regulation. A dedicated Technical Working Group was then established by the Commission to provide advice to the European Commission on possible recovery rules for nutrients from eligible materials into recovered phosphate salts, ash20
Primary reference: Meyer et al (2016) ‘Biochar Standardization and Legislation Harmonisation’ https://ec.europa.eu/transparency/regdoc/rep/1/2016/EN/1-2016-157-EN-F1-1.PDF
21
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based materials or pyrolysis materials i.e. the material being considered for inclusion in the Fertiliser Regulation, which are identified as composts, digestates, struvite, biochar and biomass ashes. Separately, the REFERTIL22 project had commenced in 2011 with the objective of improving current compost treatment systems and developing zero emission biochar technologies at the industrial scale for safe and economic nutrient recovery processes. REFERTIL also had a significant role in policy support in the revision of the Fertiliser Regulation and possible inclusion of biochar as organic fertiliser and soil additive, feeding into the proposal previously described. A specific expert working sub group was developed by the Commission, known as STRUBIAS (struvite-biocharash), which worked closely with the Joint Research Commission in developing draft proposals for the inclusion of STRUBIAS material in terms of their origin, quality, processing etc. Such proposals were put out to consultation in 2017 with, at the time of writing, are being considered, with a Final Report due by the end of 2018. The JRC, in assessing STRUBIAS materials for inclusion as ‘component material categories’ (CMCs) assess these materials against the following criteria23:
the material shall provide plants with nutrients nutrient s or improve their nutrition efficiency, effici ency, either on its own or mixed with another material. the use the materials will not lead to overall adverse environmental or human health impacts. a demand exists for such a recovered fertilising material, based on the current market and the projected future market conditions.
CMCs are identified as materials that may be utilised as component materials that can be used in EU approved fertilising products i.e. as ingredients in fertiliser products. In relation to ‘pyrolysis materials’, the JRC has considered the following:
that material may be produced from a thermochemical conversion process in oxygen-limiting conditions i.e. hydrothermal carbonisation, pyrolysis and gasification technologies. that both C-rich materials (biochars) and mineral rich materials (pyrogenic carbonaceous materials [PCMs]) be considered. that focus is on C-stable materials in line with wi th project scope as CMCs displaying soil improving properties (porosity, specific surface area etc.) and material safety correlated to C-stability. input material may be biological material and animal by-products (which would be subject to stricter thermo-chemical conditions).
The JRC proposal also considers whether the requirements of Regulation (EC) No 1907/2006 – REACH (Registration, Evaluation, Authorisation and restriction of Chemicals) apply to STRIBUIAS materials, given the potential for applying a product to soils ultimately suggests that an evaluation for REACH registration would likely be required for these materials - this conclusion is shared by the REFERTIL project participants. However, waste material streams are not covered by REACH (being covered by the Waste Framework Directive 2008/98/EC), and may be covered separately by End of Waste criteria being separately developed at a Commission level. Comparison of Standards Table 4 following, derived from Mayer et al. (2016), compares the relevant parameter values of the standards described previously, and includes the values for ‘pyrolysis’ materials as outlined in the JRC proposal of May 2017, for comparison sake.
22
http://www.refertil.info/project/brief https://www.slideshare.net/NutrientPlatform/towards-the-implementation-of-fertilisers-derived-from-secondary-raw-materials-in-the-eufertiliser-regulation-and-strubias-dries-huygens-european-commission-jrc
23
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Table 4
Comparison of relevant Biochar Standards/Quality Requirements Voluntary product standards
National Legislation
EBC IBI QUALITY REQUIREMENTS FOR BIOCHAR Organic carbon content Total Carbon Content Hydrogen/Organic Carbon Ratio Oxygen/Organic Carbon Ratio Total ash content Salinity (electrical Conductivity)
Standard
High Grade
Austria Fertiliser Ordinance
Switzerland Fertiliser Ordinance4
Italy Fertiliser Decree #75
≥20
JRC Draft Proposal 2017
≥10%
≥ 50%
≥10 2
-
-
-
≤0.7
<0.7
-
<0.4
≤0.7 -
>80
-
≥50
-
-
-
-
-
<0.7
≤0.7
-
-
-
≤1000
-
<0.7 <0.4
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
4-12
range 4-13
(% of total mass, dry basis)
-
≥30
≥20
-
-
-
≤30
≤20
-
μm
-
-
-
(g kg-1 dry matter)
-
-
-
-
-
-
-
-
5
-
-
-
-
-
-
-
-
declaration at PFC level
-
-
-
-
-
-
-
-
declaration at PFC level
-
-
-
-
-
-
-
-
declaration at PFC level
-
-
-
-
-
-
-
declaration at PFC level
Pass
-
-
-
-
-
-
-
-
-
-
-
-
-
Reporting Obligation Reporting Obligation
<20
<20
-
<6
-
-
-
-
-
-
<0.2
-
≤0.1
<0.1
-
(mg-1)
mg/kg dm
≤300
B(a)P toxic equivalency
mg/kg dm
≤3
PCBs
mg/kg dm
≤11
PFTs (PFOA and PFOS)
mg/kg dm
-
<12
<4 -
<0.2
-
≤60%
<10%
<0.5
-
-
C-rich pyrolysis materials: > 50% C
-
mS/m
Germination Test Worm Avoidance Test ORGANIC POLLUTANTS PAH content (US EPA 16)
Premium
Germany Fertiliser Ordinance
Unit (% of dry matter) (% of dry matter)
pH-Value Moisture Content (of powdery biochar) Particulate Matter <100 Macroscopic impurities (glass, metal and plastics >2 mm) Neutralising value Particle density (g cm3) Volatile organic matter (%) Specific surface area
Basic
BQM
-
≤4
<6
Yes
<4
-
0.5
<0.2
-
Page 22
PCDDs/Fs toxic equiv. (I–TEQDF)
mg/kg dm
≤17
<20
≤30 3
<20
Campylobacter species pluralis
-
-
-
-
-
-
Escherichia Coli
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Listeria moncytogenes Salmonella species pluralis
≤20 not detectable in 50 g. not detectable in 50 g. not detectable in 50 g. not detectable in 50 g.
≤20 -
<0.9
<20
-
-
-
-
-
-
-
PFC (¥)
PFC (¥) Nutrient-rich pyrolysis materials: (P2O5 + K 2O + CaO + MgO + SO 3) > 15% of dry matter
Nutrients
-
-
-
-
-
-
-
-
-
AND If P2O5> 7.5%, then (2% citric acid soluble P / total P) > 0.4
HEAVY METALS Arsenic (As) Cadmium (Cd) Chromium (Cr) Chromium VI (Cr VI) Cobalt (Co) Copper (Cu) Lead (Pb) Mercury (Hg) Manganese (Mn) Molybdenum Nickel (Ni) Selenium (Se) Thallium (TI) Zinc (Zn) Barium (Ba) Antimony (Sb) Vanadium (V) Additional requirements
Feedstock limitations
Feedstock sustainability requirements Admitted production technologies
mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm mg/kg dm
≤100 ≤39 ≤1200 ≤100 ≤6000 ≤300 ≤17 ≤75 ≤420 ≤200 ≤7400
No hazardous municipal solid waste
<13 <1.5 <90 <100 <150 <1 <50 <400
<13 <1 <80 <100 <120 <1 <30 <400
Detail Detailed ed posit positive ive list list of perm permitte itted d feedst feedstoc oc
≤100 ≤39 ≤100 ≤1500 ≤50 ≤17 ≤75 ≤600 ≤100 ≤2800
≤10 ≤3 ≤15 ≤40 ≤60 ≤1 ≤3500 ≤10 ≤10 ≤5 ≤150
≤40 ≤1.5 ≤2 ≤150 ≤1 ≤80 ≤1 -
≤40 ≤3 ≤2 ≤100 ≤1 ≤100 -
≤1 ≤100 ≤120 ≤1 ≤30 ≤400
≤1.5 ≤0.5 ≤230 ≤140 ≤1.5 ≤100 ≤500
Only Only biomas biomasss feedsto feedstocks cks
Only chemically untreated wood
-
Only chemically untreated wood
Biomass of vegetable origin from agriculture and forestry, olive pomace, grape marc, cereal bran, fruit stones and woodshells, non– treated residues of wood processing
-
Yes
Detailed requirements
-
-
-
-
Not specified
Pyrolysis and Gasification
Not specified
Not specified
Not specified
Pyrolysis and Gasification
Pyrolysis and Gasification
PFC (¥) PFC (¥) PFC (¥) < 14 (C-rich) / < 55 (nutrient-rich) PFC (¥) PFC (¥) PFC (¥) < 5 (C-rich) / < 20 (nutrient-rich) PFC (¥)
PFC (¥) < 1100 (C-rich) / 4400 (nutrient-rich) < 1 (C-rich) / < 6 (nutrient-rich) < 40 (C-rich) / < 165 (nutrient-rich)
See further proposals below
See further proposals below
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Minimum/Maximum process temperature Admitted PAH analysis methods
-
Soxhlet with toluene (EPA 8270 EPA 3540)
Min: 350 °C Max: 1000 °C
DIN EN 15527:2008– 09 with toluene / DIN ISO 13887:1995– 06: Principle B
-
-
DIN EN 15527:2008–09 DIN ISO 13887:1995–06: Principle B
-
n.a.
Methods according to the state–of–the– art of science and technology
GHG balance standard for biochar Standards to avoid GHG emissions Positive GHG balance obligatory product On–site verification Yes a Toxicity equivalents TEQ PFC (¥): parameters will be most likely regulated at PFC level in the Revised Fertiliser Regulation for which no limit values are proposed at CMC level. PFC = Product Function Category PCB (Sum of 6 congeners PCB 28, 52, 101, 138, 153, 180, mg/kg dry matter) PCDD/F (ng WHO Toxicity equivalents/kg dry matter)
Extraction solvent toluene mandatory Standards to avoid GHG emissions Yes
-
Not defined
-
Abbreviations used in the table: B(a)P – benzo(a)pyrene; C org – Organic carbon; Dm – dry matter; H – hydrogen; mS/m – MiliSiemens per meter; PFOA – Perfluorooctanoic acid; PFOS – Perfluorooctane sulfonate; PFTS – Perfluorinated tensides. Notes: 1. US EPA 7. 2. 10% stable organic carbon which is estimated to remain in the soil after 100 years. 3. ≤8 if the product is used on pastures for fodder production or on arable land without tillage. 4. in combination with the ChemRRV-ordinance and the approval of the Swiss WBF.
Further Proposals outlined in JRC Draft Proposal 2017 in relation to STRUBIAS Materials Pyrolysis materials vegetable waste from agriculture and forestry; vegetable waste from the food processing industry, unless chemical substances have been added during processing steps prior to the generation of waste; waste from the untreated textile fibres; Process materials fibrous vegetable waste from virgin pulp production and from production of paper from pulp; wood waste with the exception of wood waste which may contain halogenated organic compounds or heavy metals as a result of treatment with wood-preservatives or coating; bio-waste within the meaning of Directive 2008/98/EC other than those included above animal by-products pursuant to t he Animal by Products Regulation No 169/2009 of category II and III. Processed animal by-products input materials shall be processed under pyrolysis conditions of minimal 500°C and minimal duration of 20 minutes. Process Conditions Pyrolysis, liquefaction or gasification in an oxygen low environment with a minimum temperature of 175°C for >2 seconds (for all input materials other than animal by-products). Pyrolysis or gasification in an oxygen low environment with Core Process a minimum temperature of > 500°C for > 20 minutes (for animal by-products of category II and III). a maximum of < 25% of additives, delimited to substances/mixtures registered pursuant to Regulation 1907/2006 (REACH) of environmental release category 4 (industrial use of processing aids, in processes and products, not becoming Additives part of articles) or environmental release category 5 (industrial use resulting in the inclusion into or onto a matrix) as well as natural minerals and soil materials that are not chemically modified. The unrestricted use of water and basic elemental substances such as oxygen, noble gases, nitrogen, and CO 2. no limitations as far as positive input materials list is respected. Pre-treatment
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Quality/Technicall Parameters of Note Quality/Technica The EBC specifies a number of particular parameters that are considered of technical and quality importance in relation to biochar, which are informed by a paper by Schimmelpfennig & Glaser (2012)24. These are identified in the following. However, a number of these parameters/requirements are not specified in either the BQM or the IBI Biochar Standards. The organic carbon content is content is identified as the determinant as to whether a biochar can be considered as actually being a biochar, with the IBI and BQM requiring a minimum of 10% organic content, while the EBC requires a 50% minimum to be considered a biochar, with the German Fertiliser Ordinance requiring 80% minimum. The Hydrogen/organic C ratio must ratio must be 0.7 or less, with this ratio being an indicator of biochar stability by categorising the degree of carbonisation i.e. recalcitrance of the material, and this criterion is common across most standards identified in Table 4. Similarly, the Oxygen/organic C ratio, ratio , which must be 0.4 or less (ECB standard only), also differentiates biochar from other carbon products and is i s a further measure of biochar recalcitrance. Limits for heavy metals and organic pollutants are pollutants are also common to all standards and are important when end use applications are considered. Various ‘controls’ are applied by a number of standards relating to the process to produce biochar by specifying that pyrolysis or gasification are to be utilised (while noting the IBI and BQM standards do not apply this requirement). In doing so, minimum and maximum process temperatures are temperatures are outlined, such that the effects of temperature on biochar production in terms of biochar yield, surface area, pH and nutrient retention can be somewhat influenced through these standards. The surface area of area of a biochar, which can be influenced infl uenced by the temperature and heating rate during product ion, is identified in the EBC as an important parameter t hat reflects biochar quality which should be declared for the material produced, with a preferred value of greater than 150 m 2 /g suggested, noting than some application s may require a lower surface area.
2.3.3
Prevalence of Testing Availability in Ireland
It is understood that testing services for the range of parameters identified as being of relevance to both biochar and activated carbon material are not currently offered by any lrish based laboratory, due to the lack of demand for same, given that no significant quantities for biochar are produced in Ireland and that all activated carbon is currently imported as a finished product. Discussions with a laboratory service provider offering other biomass related testing services have indicated that there would be no significant technical obstacle to the provision of the required tests shoul d a demand for same arise, representing a potentially sizeable market opportunity for the laboratory sector in Ireland to offer the relevant testing services in the event of biochar and activated carbon production in Ireland. 2.3.4
Summary of Standards
There are a number of well-developed standards and/or quality regimes in existence for both biochar and activated carbon, as outlined. However, they are quite different in their purpose, in that the biochar standards are more related to the use of biochar in agriculture or land related applications, while activated carbon standards are wholly focussed on the performance of the material in terms of its adsorptive capacity. In the event of biochar being examined in the context of its activation and use in ‘typical’ activated carbon applications, then the standards relating to activated carbon would become more applicable to the biochar material. 24
Schimmelpfennig, S., Glaser, B., 2012. One Step Forward toward Characterization: Some Important Material Properties to Distinguish Biochars’ J. Environ. Qual. 41, 1001
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From a biochar perspective, the surface area of the material gives an indication as to the adsorptive properties of biochar, with the EBC requiring a declaration of the surface area. The surface area of biochar, often referred to as the BET 25 surface area varies, with the EBC suggesting a value of 150 m 2 /g as indicative – however, h owever, an 2 activated carbon material typically displays a BET of > 700 m /g, therefore the adsorptive properties of biochar will generally need to be increased through activation i n order to display similar performance as activated carbon in this regard. Furthermore, in the event of a biochar material being activated and applied in a specific use, it wo uld be required to display other ‘activated carbon’ properties in terms of durability and particle size distribution, for example, relative to the use to which it is being applied.
25
BET (Brunauer, Emmett and Teller) theory aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basis for an analysis technique for the measurement of the specific surface area of a material
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3 Current Biochar Market in Ireland 3.1 Introduction This section of the report outlines the status of the current biochar market in Ireland at the time of writing. Information presented herein has been gathered through desktop research and discussions and correspondence with a range of stakeholders active or with an interest in the biochar sector in Ireland at present. Firstly, a short overview of the global biochar market is presented.
3.2 Overview of the Global Biochar market The International Biochar Initiative (IBI) (www.biochar-international.org (www.biochar-international.org)) provides the most relevant overview of the global biochar market, with the ‘State of the Industry 2015’ 26 report being the most contemporary information source. Key insights outlined in this report, which was informed by survey of IBI members, identify that:
The number of companies operating in the global biochar sector grew from 200 in 2014 to 326 in 2015, representing a 63% increase – of these 79 were identified in Europe and 3 in Ireland. An increase in volume of biochar sold from c. 7,500 tonnes in 2014 to 85,000 tonnes in 2015 was observed (while noting that accurate estimation of quantities is difficult in this market). Hardwood or softwood residues (or combinations of both) were identified as feedstock for approximately half of the biochar produced, with other plant residues, rice husks, manures, coconut and cereals generally comprising the remainder. The most common biochar applications identified for biochar relate to application to soils as an amendment, for remediation purposes, for sequestration benefits or for use as a substitute growing media. It is considered that there is a significant lack of data is relation to the Asian biochar market which is considered as being significantly under-represented. The primary barrier to biochar market development identified by IBI members related to a lack of awareness of the benefits of biochar.
The IBI State of the Industry reports, also produced for 2013 and 2014 in general display an increase in activity around the biochar sector, particularly in terms of biochar production, across the years of 2013 to 2015. In a European context, the volume of pyrolysis material produced per annum is estimated at c. 10,000 tonnes, of which biochar is considered to comprise a significant proportion27. This is supported by data from the Ithaka Institute which identified approximate biochar production in Europe28 in 2012 as follows:
Germany – 5,000 tonnes (EBC certified) Austria – 500 tonnes (EBC certified) Switzerland – 700 tonnes (EBC certified) UK – 500 tonnes Other European countries – < 50 tonnes
26
https://www.biochar-international.org/commercialization/ JRC STRUBIAS Draft Report May 2017; http://susproc.jrc.ec.europa.eu/activities/waste/documents/JRC_Interim_Report_STRUBIAS_recovery_rules.pdf 28 Biochar Use, Market & Legislation In Europe; http://vec.vsb.cz/katalog-obrazku/clanek-135/245-schmidt.pdf 27
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3.2.1
Price of Biochar
There is not a significant amount of information available in relation to the market cost of biochar, and a comparison of the price of different biochar materials is very much influenced by the nature and properties of the material and the relevant ‘financial model’ applicable to its means of production and ultimate end use e.g. whether gate fees apply to input material, the ‘sophistication’ of technology used in its production, whether energy subsidy applies to a pyrolysis process and the value assigned to beneficial properties of biochar in end use etc. However, to inform this study, market prices are indicated from a number of sources, with a global average biochar price of $2,200 (c. €1,900) €1,900) per tonne being indicated29, albeit with a widely varying range from €50/tonne to €5,000/tonne observed. The 2014 IBI State of the Industry report30 also identifies an approximate global wholesale value for ‘pure biochar’ of $2/kg (€1,750/tonne) (€1,750/tonne) in 2013 and 2014. The market costs for ‘pyrolysis materials produced from biomass’, as currently offered in Europe, are identified in the JRC Draft Proposal document mentioned previously as being €357 to €642 per 1000L, equating to €1,180 to €1,180 to €2,120 to €2,120 per per tonne (at an assumed bulk density of 300kg/tonne). On the basis therefore of an average global value of €1,750/tonne, the global glo bal biochar market, at 85,000 tonnes in 2015 is worth approximately €148 million, million, with the European market, at an estimated 8,000 tonnes currently, can be estimated to be valued at €14 at €14 million.
3.3 Existing Biochar Marketplace in Ireland The current biochar marketplace in Ireland (both north and south) is considered as being in a nascent state, with very little commercial activity being undertaken therein and therefore, as identified in the introductory section of this report, it is therefore questionable as to whether a market ‘proper’ currently exists. However, there are some low value commercial dealings occurring, in addition to significant and positive activities being undertaken in the areas of research, technology and stakeholder representation, indicating a growing awareness of and interest in the potential applications and resultant benefits of biochar. General feedback received from individuals engaged in activities related to biochar identified the sector as one that display great potential but is suffering from somewhat of a ‘chicken and egg’ situation, in that a specific driver(s) or action(s) to spur further market growth is require. This is discussed further in Section 3.5. As a commercial biochar market is not yet developed, this portion of the report will provide an overview of the range of activities being undertaken in the three areas identified above (research, technology and stakeholder representation) while also outlining the level of commercial activity that has been identified. Note that the following information relates to the Republic of Ireland only – the existing biochar marketplace in Northern Ireland is addressed separately at the end of this section. 3.3.1
Commercially Available Biochar
Biochar is available for purchase via the www.biocharireland.com www.biocharireland.com website website at a rate of:
€12 per 5 kg bag €22 per 10 kg bag
Discussions with the producer of this biochar have indicated that approximately 1 tonne of biochar has biochar has been sold through this website since set up, primarily to individual gardeners or horticulturalists who have an awareness and appreciation of biochar. The biochar is produced from locally sourced hardwoods.
29 30
https://dukespace.lib.duke.edu/dspace/bitstream/handle/10161/16584/BushellMPFinal.pdf?sequence=2&isAllowed=y https://ibi.memberclicks.net/assets/ibi_state_of_the_industry_2014_final.pdf
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Biochar has also been produced over the past number of years, and continues to be produced, at a rate of approximately 1 m3 per month month by Premier Green Energy (www.pge.ie (www.pge.ie)) at their pilot pyrolysis facility in Tipperary, which is described in more detail in a case study outlined at the end of this section. Feed material used in production of this biochar is typically locally sourced Sitka spruce, with the biochar material generally given to local organic farmers gratis. Other feedstock materials are al so trialled at various time at this facility as part of various research projects undertaken. In addition, an Irish landscaping company specialising in urban greening solution has, over the past 2 years, utilised an estimated 5 tonnes of tonnes of biochar material that they have sourced through a UK biochar company, for specific applications in individual urban greening projects that they have delivered, citing its beneficial properties in terms of soil structure, water holding capacity and nutritional benefits as reason for the use of this material. 3.3.2
Biochar Research & Projects
A number of entities have or o r are undertaking research in relation to biochar and its potential applications in Ireland. In preparing this report, we have engaged with a number of these entities who were happy to discuss the extent of the research they have undertaken, and a summary overview of same is provided in the following. University of Limerick/Carbolea The Carbolea Research Group in the University of Limerick between 2011 and 2018, have been actively engaged in research relating to biochar, having been in involved in four significant projects on the topic, namely:
As part of the ReUseWaste31 European project, where the role of biochar in carbon sequestration and in methane emissions reduction was investigated. Through the DIBANET32 research project, funded by the EU Seventh Framework Programme and led by the Carbolea team, which investigated the benefits of biochar produced from sugar cane bagasse wh en used as a soil amendment. As part of the ‘PBX2 - Pyrolysis of Biomass for Power and Biochar’ 33 project in association with EOS Design and other partners, which was funded by the SEAI under the Energy Research, Development & Demonstration (RD&D) Programme, which assessed the technical and economic feasibility of the pyrolysis of biomass for energy and a high value feed grade biochar in the Irish context. Enterprise Ireland project which assessed the pyrolysis of dairy sludge.
National University of Ireland, Galway/Teagasc The National University of Ireland, Galway, in association with Teagasc, have undertaken a number of studies in relation to biochar, as follows:
assessment of the performance of a range of chemical amendments, including biochar on the release of greenhouse gas emissions from cattle slurry. assessment of the impact of greenhouse gas release form biochar applied to Irish tillage soils. assessment of the impact of biochar application to pig manure amended soils in terms of nutrient leaching. assessment of the impact of sawdust addition and composting on the energy yield of the biochar produced from the pyrolysis of anaerobically digested pig manure.
31
www.reusewaste.eu http://www.dibanet.org/ 33 http://www.pluschar.ie/wp-content/uploads/2017/01/PBX2-Main-Text-Final-5-11.2.15-4.pdf 32
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Post-doctoral research is also currently being undertaken at NUIG in relation to the potential of biochar in contaminated land treatment, particularly in relation to trichloroethylene.
Bord na Móna Having previously undertaken investigations in relation to biochar and activated carbon in the 1990’s, Bord na Móna is currently supporting Ph.D research through Dublin Institute of Technology (DIT), which is assessing the characteristics, nature and performance of biochars produced from peat and other organic feedstocks, to determine whether there exists any potential for the future development of ‘higher value’ products produced from these feedstocks. Other Research & Projects Agrichar, an EPA Strive funded project undertaken by EOS Future Design in partnership with the University of
Limerick, was undertaken over a two-year period and sought to replicate the research findings and field trial results achieved by the Ithaka Institute on the use of amended biochar in agriculture through investigation of biochar application to slurry pits, as well as an additive to silage. A number of biochar research research papers have also been contributed to by Dr. Munoo Prasad, formerly Chief Scientist at Bord na Móna and owner of Compost/AD Research & Advisory, including:
Synergistic use of peat and charred material in growing media – an option to reduce the pressure on peatlands?34 Chemical characterization of biochar and assessment of the nutrient dynamics by means of preliminary plant growth tests35 Biochars in soils: towards the required level of scientific understanding36
Agriforvalor 37 is an EU Horizon 2020 Research and Innovation Programme project, focussed on the valorisation
of agri and forest residues, which is overseen by three Biomass Innovation Design Hubs, one of which is located in Ireland. Biochar produced from agricultural residues is a ‘sidestream’ being focussed on by the Irish design hub partners. Funded as part of the Agricultural European Innovation Partnership, the Biomass to Biochar for Farm Bioeconomy project project38 is a recently commenced project running in Ireland to demonstrate a methodology for Irish agriculture to develop a carbon-neutral approach to the management of undesirable biomass while at the same time increasing farm productivity. As part of th e project, a mobile pyrolysis unit will be built and tested to produce biochar on-site with farmers who will act as producers and end-users. This project aims to pilot the conversion of unutilised agricultural biomass, arising from management of pasture with rushes (Juncus spp.) and other problem species into stable forms of recalcitrant biocarbon which can, when redeployed to the soil, confer multiple ecosystem benefits, driving an innovative bio-economy on and off the farm. 3.3.3
Biochar Related Technology
A number of companies are involved in the development and manufacture of pyrolysis units that can be utilised for biochar production, namely Premier Green Energy39 and Heat Systems 40. While there are other companies in Ireland who operate in the pyrolysis sphere, their main focus tends to be on pyrolysis in terms of plastic conversion or municipal waste treatment, and so are not examined further herein.
34
https://www.tandfonline.com/doi/abs/10.3846/16486897.2017.1284665 https://www.researchgate.net/publication/316080654_Chemical_characterization_of_biochar_and_assessment_of_the_nutrient_dynamics _by_means_of_preliminary_plant_growth_tests 36 http://collections.crest.ac.uk/15087/1/Simon%20Jeffery%20Biochars%20in%20soils%20towards%20the%20required%20level%20of%20 scientific%20understanding%2019%20Sep%2016%20upload.pdf 37 http://www.agriforvalor.eu/pages/about 38 https://ec.europa.eu/eip/agriculture/en/find-connect/projects/biomass-biochar-farm-bioeconomy-bbfb 39 https://www.pge.ie/ 40 http://heatsystems.ie/renewables.html 35
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A case study of Premier Green Energy is included at the end of this section, section , while Heat Systems are discussed in more detail in relation to activated carbon regeneration in Section 4.3.6. Biochar production by individuals or small community group can be facilitated using the Kon Tiki kiln, based on the open source design by the Ithka Institute, which is available for purchase through the www.pluschar.ie website, and which is manufactured by Premier Green Energy. 3.3.4
Biochar Stakeholder Representation
The Irish Biochar Co-operative Society Ltd. was set up in 2016, using a standard co-operative model and was set up by a number of individuals who are currently active and interested in the biochar sector, in terms of the extent of research undertaken to date and the commercial activity that has been ongoing. The special objectives of the co-operative are listed as being to “promote, research, produce, process, develop, market, sell, certify, record, buy and use biochar-based and biochar related products to benefit Biochar Co-operative Members, soil and animal health, biodiversity and the wellbeing of wider society and environment”.
The future intention of the organisation is to develop into a multi stakeholder co-operative which will allow full representation and membership to all individuals involved, be they producers, workers, users and the wider community.
3.4 Existing Biochar Marketplace in Northern Ireland In relation to Northern Ireland, we have found no evidence of any commercial activity in biochar being undertaken in Northern Ireland, having undertaken desktop research and through discussion with a number of individuals involved in the wider biomass sector in Northern Ireland. It does not appear that any biochar is being produced at present, even at a small scale for domestic horticulture or similar uses. From a research perspective however, representatives of the anaerobic digestion sector in North ern Ireland are currently commencing an industry led study, in association with Queens University of Belfast, into the extraction of the energy value of the lignin content conten t of the solid fraction of anaerobic digestion digest ion digestate through pyrolysis, with the heat output from the realised r ealised energy content of syngas and oils produced being utilised in evaporation of the liquid digestate fraction to a more concentrated material. These investigations have been prompted by the current situation where the financial value of the nutrient content of digestate is generally negated by transportation costs associated with same.
3.5 Barriers to/Opportunities to/Opportunities for the Development of the Biochar marketplace While beyond the scope of this report to analyse in detail the existing barriers to or opportunities for the development of the biochar market in Ireland, it is worth providing a summary of the sentiment reflected by individuals involved in the sector in terms of the potential next steps and drivers that may be required to progress the sector. As seen on a global perspective as referenced in the IBI ‘State of the Industry 2015’ report identified previously, a lack of awareness of biochar and its benefits by the most appropriate end-users i.e. the wider agricultural sector and commercial horticultural sectors, is generally seen as the first ‘hurdle’ to be overcome in attempting to stimulate market development. The topic of biochar was described by one stakeholder quite aptly during discussions as being an esoteric subject in Ireland at present. It is felt across the sector that biochar can have a strong role to play in a number of different areas influenced by government policies and schemes, in terms of greenhouse gas emissions and climate change related policy, renewable energy policy and nutrient management, with a requirement for a clear mechanism of calculating benefits accruing from biochar utilisation in terms of emission, being identified by the sector.
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The potential for adoption/utilisation of biochar in terms of marginal land management in keeping with the requirement of the GLAS scheme were also highlighted highli ghted by the sector, with the outcome out come of the ongoing revision of the Fertiliser Regulation identified as a strong potential ‘market activation instrument’ for the generation of a market for STRUBIAS materials, assuming the adoption of these materials as CMCs (refer to Section 2.2.2 previously). An interesting comparison can be made with other representative organisations globally, where the biochar industry is at or has been at a similar stage to that currently in Ireland – a 2015 report 41 addressing the development of a commercialisation strategy for biochar market development in the US Pacific Northwest region identified the following biochar market barriers relevant to that location as being:
Lack of policy incentives.
Lack of product specifications & standardisation.
Need for high-profile demonstration projects.
Lack of understanding of end user concerns.
Limited market demand.
Perhaps with the exception of the product specification and standardisation (given the development of the European Biochar Certificate, Biochar Quality Mandate etc.), all of the barriers identified in this report can be considered as being applicable to the Irish biochar sector, while noting the pot ential for the RE-DIRECT project, and others ongoing, to satisfy the barrier in relation to demonstration projects. The same report also outlines the resources required to overcome the identified barriers, which again can be considered as being relatable in an Irish context, as follows:
Policy priorities that can be shared with elected officials.
Marketing collateral for different market segments.
Customer and end-user needs assessment.
Funding for demonstration projects.
Collaborations and strategic partnerships.
41
Northwest Biochar Commercialization Strategy Paper, 2015; http://nwbiochar.org/sites/default/files/sites/default/files/attached/nw_biochar_strategy_02-24-15.pdf
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CASE STUDY NO.1
ADVANCED THERMAL TREATMENT TECHNOLOGY MANUFACTURING MANUFACTU RING INCLUDING PYROLYSIS SYSTEMS
Name:
Premier Green Energy Ltd.
Address:
Cabragh Business Park Cabra Thurles Co. Tipperary
Contact:
Sean O’Grady
Contact Email:
[email protected]
Premier Green Energy (PGE) was established in 2010 as a spin-off from its parent company OMC Technologies Ltd. to develop bespoke technology related to the thermal conversion of biomass and other organic materials. The embedded fabrication, design, manufacturing and process knowledge and experience gained from OMC was considered to be highly transferrable to the development of renewable energy technologies. Today PGE designs and manufactures a customised range of renewable power generations plants, in addition to a wide range of components related to energy generation including reactors, heat exchangers, combustion units, condensers and control systems. PGE’s primary focus is on its Prima Advanced Prima Advanced Thermal Treatment (ATT) pyrolysis conversion technology that can process a range of biomass (and non-biomass) input materials to produce synthetic gas (syngas), oils and biochar, in variable ratios, depending upon process configuration. PGE are currently in the process of developing a 4 MWe facility in Wales utilising the Prima technology Prima technology for the conversion of solid recovered fuel (SRF) into clean, renewable electricity. From a biochar perspective, the Prima technology Prima technology can be configured in a suitable manner to maximise biochar production from appropriate input materials through varying residence time, pressure, process temperature etc. but the objective of any system configuration is an important consideration. “In our opinion, the preferred model for biochar production using a pyrolysis system such as our Prima technology would see the installation of a pyrolysis unit either co-located or located very close to a sustainable feedstock source. In this context, the process would be configured in CHP mode for maximum renewable electricity generation as the primary ‘product’, though combined with waste heat recovery channelled through a district heating network. Simultaneously a high-quality biochar material will also be produced as a secondary product from which maximum value can be derived, either for example as a feed additive and/or as a soil conditioner product,” says Sean O’Grady, Senior Technical Engineer with PGE. “Such a configuration could facilitate or be complimentary to the establishment of local or regional co-operatives, such that providers of feedstock, employees, end users and the wider community all have an opportunity to be involved in a sustainable energy model.” PGE has, to date, been actively involved in research utilising their Prima technology, with two pilot-scale pyrolysis plants located at their fabrication facility at Thurles (pictured above). They have closely collaborated with the University of Limerick and others in the PXB2 project and with University College Cork in the European Union funded DEPOTEC project and have also participated, as an industrial partner, in the RENEW project with Queens University Belfast. Similar research activities in conjunction with the Technology Centres of Biorefining & Bioenergy and Dairy Processing have been undertaken. PGE is also involved in the previously identified Biomass to Biochar for Farm Bioeconomy project, where they will develop a mobile pyrolysis unit for demonstration and application as part of the delivery of that project. Furthermore, for those interested in smaller scale biochar production using simpler technology, PGE also manufacture the Kon-Tiki kiln which is marketed marketed through the www.pluschar.ie website.
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4 Current Activated Carbon Market in Ireland 4.1 Introduction As with the assessment of the biochar marketplace, the activated carbon market was investigated through desktop research, discussions and correspondence with supplies, distributors and end users of activated carbon in Ireland. Unlike the biochar market, the activated carbon market in Ireland is relatively well established, with the use of activated carbon in a range of applications being well demonstrated and accepted.
4.2 Overview of the Global Activated Carbon market The global activated carbon market is identified as being worth US$3.7 billion in 2016, US$4.2 billion in 2017 and is projected to grow to US$10.2 billion by 202442, driven by increased use of activated carbon for mercury removal at power plants and in water purification applications. Globally, the most common activated carbon source materials comprise coal (bituminou s, sub-bituminous, lignite and anthracite), coconut shells, wood-sawdust (soft as well as hard) and peat, with walnut shells, olive stones and palm kernels also being used to various degrees. The global production of activated carbon is estimated at 1 million tonnes per annum43. In 2017, powdered activated carbon accounted for the majority of the global demand, a trend which is expected to continue in the coming years while liquid phase applications, in particular water treatment, is identified as the leading application for activated carbon use, accounting for 41% of total consumption44. Air and gas purification account for 30%, and food processing at 14%. Activated 14%. Activated carbon consumption varies by by region, both both in terms of application and growth rate. In the United States for example, activated carbon for food processing applications accounts for over 7% of the total whereas in China food processing applications made up 25% of the total. Global activated carbon consumption per region in 2016 is shown in Figure 1 following. Figure 1
Global Activated Carbon consumption in 2016
42
https://globenewswire.com/news-release/2018/08/14/1551338/0/en/Global-Activated-Carbon-Market-to-witness-a-CAGR-of-12-1during-2018-2024.html & OEC data during-2018-2024.html & 43 http://biofuelsdigest.com/nuudigest/2016/10/11/an-overview-of-the-current-biochar-and-activated-carbon-markets/ 44 https://ihsmarkit.com/products/activated-carbon-chemical-economics-handbook.html
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Globally, activated carbon production is dominated by a relatively small number of large companies that produce and market a wide range of activated carbon products and the main global activated carbon companies are outlined in Table 5. Table 5
Main Global Activated Carbon producers Company
Headquartered
Cabot Corporation (Norit)
US
Calgon Carbon Corporation (Chemviron)
US
Kureha Corporation
Japan
Jacobi (Osaka Gas Chemical Co. Ltd.)
Japan
Haycarb PLC (Eurocarb)
Sri Lanka
CarboTech AC Gmbh
Germany
CECA Speciality Chemicals (Arkema)
France
Indo German Carbons Limited
India
DESOTEC Activated Carbon
Belgium
China Fujian Zhixing Activated Carbon Co. Ltd
China
Oxbow LLC
US
ADA Carbon Solutions LLC Evoqua Water Technologies LLC Albemarle Corporation
US US US
Donau Carbon
Germany
SICAV
Italy
Silcarbon Aktivkohle
Germany
As per the OEC 45 2016 data, Asia is identified as the largest exporter of activated carbon (45%), followed by Europe (30%) and North America (21%), with the remainder from South America, Oceania and Australia (c. 1.2% each).
4.3 Existing Activated Carbon Marketplace in Ireland In assessing the current activated carbon marketplace in Ireland, the following steps were taken in identifying the scale of the existing marketplace and the primary applications for which activated carbon is currently used:
Desktop research to identify suppliers/distributors of activated carbon and review of other available information in terms of trade data, environmental compliance reports etc. Discussion with the identified suppliers and distributors to attempt to quantity market size, relevant applications and appropriate costs. Identification of relevant entities in the sectors of primary use and discussions with end-users.
A number of broad statements can be made in relation to the existing activated carbon marketplace marketplace in Ireland:
No activated carbon production occurs on the island of Ireland and therefore all activated carbon is imported. The activated carbon market is well developed, with the primary sectors for activated carbon use, in terms of volume, being identified by suppliers/distributors as being the waste management industry,
45
Observatory of Economic Complexity https://atlas.media.mit.edu/en/profile/hs92/3802/
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the water treatment sector and the wastewater treatment sector – other, more specialist applications requiring very high specification material, such as t he food industry, do utilise activated carbon but only in very small volumes compared to the main sectors identified. 4.3.1
Suppliers/Distributors of Activated Carbon in Ireland
The majority of activated carbon placed on the market is distributed through a relatively small number of suppliers as identified in the following table. Material can also be directly sourced from suppliers located in the UK or elsewhere, but it is considered that the companies identified in the following ‘channel’ the significant majority of the volume utilised in the Irish market. Table 6
Activated Carbon Suppliers/Distributo Suppliers/Distributors rs in Ireland
Supplier Acorn Water
Location
Description
Cork
Distributor for major international manufacturer of activated carbon for use in municipal and domestic drinking water treatment, tertiary waste water treatment, raw material purification, industrial plants, dairy plants, and as a catalyst. Brenntag is a chemical distribution company and the global market leader in full-line chemical distribution. It supplies over 10,000 products to the life sciences, environmental, cosmetics, pharmaceutical and manufacturing sectors. Supplies a range of 62 different Cabot Norit Activated Carbons from 1kg to 500kg packing packing sizes. Supplier of Activated Carbon from CPL Carbon Link to agricultural, anaerobic digestion, biochemical, water and wastewater treatment sectors in the Irish market. Supplying pelletised, granular and powdered forms for applications to air or water. Produced from charcoal, coconut and wood for water treatment, food and chemical processing, pollution and oil/gas refineries. A hazardous waste recovery and water services provider, Enva Ireland Ltd supplies Jacobi Carbons activated carbon for water/waste water treatment, air purification, odour abatement, colour removal. Liquid and vapour phase applications for municipal, industrial and commercial customers. A water treatment solutions provider that supplies Jacobi Carbons activated carbons (AquaSorb), and solutions in industrial and municipal water treatment, odour control, de-icing, mining chemicals, defoamer (Anti-Foam).
www.acornwater.ie
Brenntag
Dublin, Belfast
https://www.brenntag.com/ukireland/
Nova-Q Ltd.
Dublin
http://www.nova-q.ie/
Enva Ireland Limited
Dublin
https://www.enva.com/
Clearwater http://www.clearwater.ie/products/
Leitrim Louth
In terms of the origin of material imported to Ireland, the OEC data for 2016 identifies the countries of origin as being:
UK – 43% United States – 22% Netherlands – 11% Japan – 5.7% Belgium – Luxembourg – 5.1%
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China – 4.1% Germany – 4.0% Other European Countries combined46 - 5.1%
Given that the UK is the primary origin of activated carbon material, and given that activated carbon production in the UK is minimal, material imported to Ireland from the UK has initially been imported to the UK also – OEC data for 2016 indicates that the following import origins for the UK, which can be taken as a rough approximation of the origin of the activated carbon imported to Ireland from the UK also:
4.3.2
Europe – 53% (Belgium/Luxembourg largest at 27%) Asia – 34% (India largest at 13%) North America – 9% Others – 4%
Quantification of Activated Carbon Market in Ireland
In attempting to quantify the size of the activated carbon market in Ireland at present, two approaches were considered – taking a ‘top down’ approach based on identification of the quantity of activated carbon entering the country and taking a ‘bottom up’ approach based on identification of individual users and quantification of their usage. In practice, a combination of both approaches was taken as, while both suppliers and end users were relatively obliging in discussing activated carbon in general, specific information regarding volumes, costs etc. was, in some cases, not readily forthcoming due to reasons of commercial sensitivity. The following subsection addresses quantification of activated carbon usage in the Republic of Ireland (RoI) only. Quantification of the activated carbon market for Northern Ireland is addressed separately in an individual section in the following. ‘Top down’ approach In attempting to follow a ‘top down’ approach, the Central Statistics Office (CSO) Trade Statistics were initially examined to identify quantities of activated carbon that have been imported into the RoI in the recent past, given that all activated carbon material utilised in the country is imported. The CSO Trade Statistics47 identify an individual Standard International Trade Classification (SITC) code for activated carbon material (598.64) imported, with data available at time of writing, until May 2018. Quantities and euro value assigned for 2016, 2017 and (part) 2018 are shown in Table 7. Table 7
CSO Trade Statistics for Activated Carbon (SITC 598.64) imports in Republic of Ireland Quantity (hkg)48
Quantity, t
Jan - Dec 2016
5275
527.5
1,985,000
Jan - Dec 2017
6165
616.5
1,890,000
Jan - May 2018
3492
349.2
1,048,000
Jan – Dec 2018 (projected)
6984
698.4
2,096,000
Period
Value, total €
46
France, Italy, Sweden, Switzerland, Poland Denmark, Spain https://www.cso.ie/en/statistics/externaltrade/goodsexportsandimports/ 48 As reported in Trade Statistics where hkg = 100kg 47
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A quantity of 616.5 tonnes was identified as being imported in 2017, with close to 700 tonnes being projected (pro rata) for 2018. Activated carbon may also be classified under SITC code 598.65 598.65 under the heading ‘Activated natural minerals, including animal black’, with the CSO data for this material presented in Table 849. Table 8
CSO Trade Statistics for ‘Animal Black (SITC 598.65) imports in Republic of Ireland Period
Quantity (hkg)
Quantity, t Quantity,
Value, total €
Jan - Dec 2016
2218
221.8
1,281,000
Jan - Dec 2017
2315
231.5
1,018,000
Jan - May 2018
938
93.8
440,000
Jan – Dec 2018 (projected)
1867
186.7
880,000
On face value, this would seem to represent the size of the activated carbon market but, based on other analysis, as outlined in the following sections, this figure appears lower than may have been expected by the authors. Therefore, talking a ‘top down’ approach suggests a quantity of c. 850 tonnes of activated carbon and other activated materials being imported into the country in 2017. While it cannot be identifi ed from the data whether all material imported under SITC code 598.65 is utilised in specific activated carbon applications (as animal black material may also be used in other applications), it is considered that 800 tonnes tonnes represents a relatively accurate quantification of the activated carbon imported in 2017. What is also evident from the CSO data presented is the increased demand for these material over the past 3 years, suggesting a growing market, in keeping with the global trend for increased activated carbon demand as identified previously. Having identified relevant trade data using the ‘top down’ approach, a ‘bottom up’ view was taken in order to attempt to validate the trade related information. ‘Bottom up’ Approach The identification of individual users assessed in following the ‘bottom up’ approach was informed through discussion with activated carbon suppliers, users themselves in some cases and through review of publicly available information, such as annual environmental returns and similar information. As referenced previously, the main sectors identified as utilising the majority of activated carbon in the country are the waste management sector and the water & wastewater sectors. Other sectors such as pharmachem and food production are also identified as being users, with a wide variety of applications potentially applying to these sectors, but in terms of volume of material used, the waste, water and wastewater sectors are focussed on herein. It should also be noted that in taking a ‘bottom up’ approach it is not possible to accurately identify every user in the waste, water and wastewater sectors, nor any other sector, and so volumes identified in the following should be considered with this in mind. Consideration of volume and type of material utilised in other sectors is addressed separately in the following also.
49
Note that activated carbon, activated natural minerals and animal black are also classified together under a different commodity classification known as the harmonised system (HS), where the code HS3802 covers ‘Activated carbon, activated natural mineral, animal black and spent animal black’
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Waste management sector
A number of applications utilise activated carbon in the waste management sector, in uses including:
as an odour control media. as a flue gas treatment compound. as a gas scrubbing media (landfill gas/biogas).
Table 9 identifies the waste management facilities in the Republic o f Ireland where it is understood that activated carbon is utilised.
Table 9
Waste Management Facilities utilising Activated Carbon
Name Dublin Waste to Energy Carranstown Waste to Energy Thorntons Recycling Killeen Road Greyhound Crag Avenue
Licence No.
Quantity p.a., tonnes
Application
Type
Source
W0232-01
240
Flue gas treatment
PAC
AER 2017 (138 over 6 months) – 138 x 2 ~240 tonnes
W0167-03
100
Flue Gas treatment
PAC
AER 2017
W044-02
40
Odour control
GAC
W0205-01
35
Odour control
GAC
W0144-01
35
Odour Control
GAC
P1015-01
55
Odour control
GAC
W0136-03
30
Odour control
GAC
Enva Clonminam
W0184-02
40
Air treatment
GAC
EPA documentation (estimated)
Ballymount Recycling Centre
W0003-03
30
Odour control
GAC
AER 2017 (assumed quantity)
Indaver Dublin Port
W0036-02
30
Air treatment
GAC
AER 2017 (assumed quantity)
GAC
EPA documentation (assumed quantity and type) – remediation project, limited lifetime
Oxigen Coes Road Glanway Transfer Station Greenstar Sarsfield Court
Personal comms EPA documentation (assume replacement twice per year) EPA documentation (assume replacement twice per year) EPA documentation (assume replacement twice per year) AER 2017
Limerick Gas Works
W0281-01
40
Land remediation project
Greenstar Cappagh
W0261-01
40
Odour control
GAC
EPA documentation
Landfill Facility
-
120
Landfill gas scrubbing
GAC
Personal comms, impregnated GAC
835
340 tonnes PAC, 495 tonnes GAC
Total
While Table 9 suggests an annual demand from the waste management sector of 835 tonnes, this figure is based on the assumption of replacement of activated carbon in odour/air treatment units twice annually which would be typical ‘best practice’ in terms of odour control or air treatment – however, it may not be the case that this occurs or is required in all instances. In addition, activated carbon utilised at the land remediation project represents a use associated with a project of limited timeframe and may not be a long-term outlet for activated carbon. Therefore, a more realistic annu al volume required by the waste management sector may be 650 tonnes per annum. annum. – of this, the PAC quantity will remain relatively constant, therefore 340 tonnes of PAC and 310 tonnes of GAC. The different applications for which activated carbon is used apply different types of material. When used in flue gas treatment, powdered activated carbon (PAC) is injected into the flue gas with lime, for the removal of heavy metals and dioxins/furans through physical and chemical adsorption. When used in odour control and air treatment, granular (or extruded) activated carbon (GAC) is utilised within odour control or air treatment units where air from a processing building or specific process is typically vented
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through the activated carbon bed prior to release to atmosphere to remove odorous or other compounds. A specific case study addressing odour treatment is included at the end of this section. A general specification for activated carbon material utilised in odour control is as follows:
Base Carbon type CTC (CCl4 Activity)50 Moisture Pellet diameter Hardness Bulk density Ignition temperature Ash Surface area Iodine number
Coal (typically) 60 % w/w min 5% max 4 mm +/- 20% 95 – 97% 0.45 to 0.47 kg/l 400 deg C 8 – 13% 900 – 1000 m 2 /g 900 - 1000 mg/g
Activated carbon utilised for gas scrubbing is typically granular activated activated carbon, targeted for hydrogen sulphide removal (H2S) from the landfill (or biogas) stream, which would typically be an impregnated material.
Water treatment sector
As part of this study, a formal request was made to t o Irish Water (IW) for information informatio n in relation to the use of activated carbon at water treatment and wastewater facilities under its control. In relation to drinking water treatment, IW was in a position to confirm the quantity of activated carbon it procured in 2017 for use at water treatment facilities directly under its control, where it is primarily utilised for pesticide removal and taste improvement applications. Activated carbon used in water treatment by Irish I rish Water is exclusively powdered material (PAC). The quantity procured in 2017 is outlined in the following table, with a small allowance included for assumed activated carbon consumption at water treatment assets which are not directly operated by Irish Water i.e. ‘design, build, operate’ (DBO) assets.
Table 10
Irish Water Activated Carbon usage in water treatment in 2017 Facilities Irish Water (non DBO) DBO (on behalf of Irish Water)
Quantity p.a., tonnes 95.5 251
Type PAC & wetted PAC as above (assumed)
In addition, contact was made with the National Federation of Group Water Schemes (NFGWS) to identify whether activated carbon material is utilised in water treatment within the group water scheme sector. It was confirmed that only in a small number of pilot projects has activated carbon been used as a final polishing treatment step, in very small volumes i.e. tens of kgs and therefore this sector has not been considered con sidered further.
Wastewater treatment sector
The reverse situation applies to wastewater treatment as to water treatment in the RoI, in terms of the direct operation of wastewater facilities under control of IW. Wastewater treatment facilities are typically operated on
50
The Carbon Tetrachloride Activity (ASTM D3467) measures the loading of carbon tetrachloride, weight percent on carbon, at concentratio ns close to saturation in the air – a vap our phase application quality parameter 51 On the basis that DBO facilities provide treatment for c. 125,000 population equivalent, equating to approximately 2.5% of national population, pro rata to IW value suggests 2 tonnes approximately.
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a DBO (design, build, operate) basis by 3 rd parties on behalf of IW and information concerning activated carbon usage at these facilities is not recorded by IW, as it isn’t directly procured by IW. Contact was made with the main companies operating wastewater treatment facilities on behalf of IW and responses were provided by a number, but not all, companies contacted. In some instances, information for individual sites was deemed commercially sensitive and therefore the information presented in Table 11 represent an estimated figure, based on information provided and assumptions where information is absent, for annual activated carbon usage at wastewater facilities operated by DBO contractors on behalf of Irish Water.
Table 11
Quantification of Activated Carbon usage in wastewater treatment Process DBO operated wastewater treatment facilities
Activated carbon usage (GAC) 110 tonnes p.a.
Other Applications
Discussions with activated carbon suppliers have identified that activated carbon is used in other applications, such as food production and pharmachem. However, quantification of such uses is difficult given the generally small quantities (< 5 tonnes per annum) used and broad range of such applications. For example, activated carbon can be provided in small con tainerised, preloaded systems for air treatment uses in the pharmachem and other sectors52; as part of air conditioning filtration filtrati on systems53 and as a food supplement. There are a variety of food supplement or healthcare products available on the Irish market that identify themselves as being an activated carbon or ‘activated charcoal’ material or containing these as activated ingredients. The terms ‘activated charcoal’ and ‘activated carbon’ can be used interchangeably in these applications and any such use in these applications would require an activated carbon material produced in accordance with the specifications as laid down in the Food Chemical Codex, as referenced previously. In attempting to quantify activated carbon use in the range of applications not related to waste management, water or wastewater treatment, discussion with activated suppliers have suggested that as assumption of 75 tonnes of activated carbon (assumed at a 50:50 split between GAC & PAC) being consumed in these applications annually would be appropriate. A review of available documentation for non-waste management, waste or wastewater related facilities, identified some sites where spent activated carbon is generated, indicat ing a usage in certain processes therein – these include:
Diageo St. James Gate Brewery - 17.7 tonnes 54 Bellanaboy Bridge Gas Terminal – 2.75 tonnes55 Intel Leixlip – 3.85 tonnes56 United Fish Industries – 3 tonnes57
Therefore, on the basis of sites identified where information is publicly available, as above, the estimation of 75 tonnes for ‘other applications’ is considered reasonable, to cover applications where no publicly available information exists.
52
Examples of such product can be found here: https://www.wtlireland.com/uploads/Carbon_filter_systems.pdf https://www.enviropro.co.uk/entry/33984/Chemviron-Carbon/Protect-Ventsorb-60-activated-carbon-adsorber/ 53 http://www.camfil.ie/Filter-technology/Principles-of-Filtration/Carbon-filtration/ 54 AER 2016; http://www.epa.ie/licences/lic_eDMS/090151b280604622.pdf 55 AER 2017; http://www.epa.ie/licences/lic_eDMS/090151b280673d4d.pdf 56 AER 2015; http://www.epa.ie/licences/lic_eDMS/090151b2805a15a0.pdf 57 AER 2017; http://www.epa.ie/licences/lic_eDMS/090151b2806afff4.pdf
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&
Comparison of Approaches to quantify market Taking a ‘top down’ approach as identified previously suggests a quantity of c. 800 tonnes being imported into the Republic of Ireland in 2017. The ‘bottom up’ approach suggests a potential annual demand for activated carbon in the Republic of Ireland of approximately 932 tonnes, on the basis of identification of as many end users as possible and the application of reasonable assumptions. Table 12 summarises these findings.
Table 12
Findings of Different Approaches
Approach Taken
Sectors
Top Down Approach
All Waste Managements Water Treatment
Bottom Approach
Up Wastewater Treatment Others
Summary
Material PAC
Tonnes
Comment
GAC PAC GAC PAC GAC PAC
800
Not differentiated in trade data
340 310 97.5 -
Assumed demand as per Table 9
GAC
110
PAC GAC
37.5 37.5 800 932.5
Top Down Bottom Up
As reported No evidence of use No evidence of use Estimation based on sectoral feedback Assumed Assumed PAC 475; GAC 457.5
While a difference is observed between both approaches, the difference is not sizeable, especially given the assumptions that have been made as part of the ‘bottom up’ approach, and therefore it can be considered that both approaches broadly validate one another and a degree of confidence can be determined form the numbers identified. However, for the purposes of assigning values to the sector as outlined in following sections of this report, an intermediate value of 850 tonnes is tonnes is taken as the annual activated carbon market in the Republic of Ireland, with an assumption as being evenly split as 425 tonnes of of PAC and GAC each. 4.3.3
Activated Carbon Market in Northern Ireland
Assessment of the sectors as identified was also undertaken for Northern Ireland.
Waste Management Sector
Publicly accessible records in relation to environmental performance of waste management facilities are not as readily available for Northern Ireland as they are in the Republic. To this end, it is difficult to identify facilities where activated carbon is utilised in odour control or air treatment. In addition, the first energy from waste facility has commenced operation in Northern Ireland in 201858, which may represent an emerging significant activated carbon user – however, quantification of activated carbon used in this application is not readily identifiable. In the absence of publicly available information, an estimation based on populations statistics i.e. population of Northern Ireland being 40% of that of Republic of Ireland, and applying this to the potential GAC demand in the waste management sector in Ireland as identified in Table 9, suggests 125 tonnes as a potential GAC
58
https://riverridge.co.uk/app/uploads/2017/03/FCG.pdf
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demand in Northern Ireland’s waste sector, on the assumption that similar odour control issues are experienced at waste facilities in Northern Ireland as in the Republic, at a similar distribution. In addition, an industry median value of 0.25 kg per tonne of input material59 is applied to account for potential demand for activated carbon at the new energy from waste facility, which accepts 120,000 tonnes per annum, therefore 30 tonnes of activated carbon demand is assumed at this facility. Therefore, overall activated carbon demand from the waste management sector in Nort hern Ireland is assumed at 155 tonnes per annum.
Water & Wastewater Treatment Sectors
As with Irish Water, a formal request was made made to Northern Ireland Water requesting information in relation to the usage of activated carbon at water wat er and wastewater facilities operated by NIW. A response was provided by NIW, which indicated that water treatment and wastewater treatment plants in Northern Ireland are operated directly by NIW, as well as by contractors through public private partnership (PPP) arrangements. The following followi ng table summarises data received from NIW.
Table 13
Non-PPP sites
Activated Carbon utilised by Northern Ireland Water
Water Treatment
Wastewater Treatment
2,921 tonnes in GAC filters across all water treatment works
Cannot be confirmed
180 tonnes replaced in 2016 51 tonnes virgin carbon installed in 2017 2,430 m 3 (c. 1,020 t) in place in GAC filters
PPP sites
3
105 m (c. 44 t) replaced in 2016 157 m3 (c. 66 t) replaced in 2017 30 tonnes PAC annual consumption
25 no. sites in total – in 2017, one site replaced 2.7 tonnes and in 2018 one site replaced 1.1 tonnes but a combined figure not available GAC in wastewater odour control 2016 – 26.75 tonnes 2017 – 24.75 tonnes Adsorber for thermal treatment 40.25 tonne in 2017
In terms of water treatment, treatment, NIW utilises granular activated carbon (GAC) filters as a core treatment technology and therefore have a significant quantity of GAC material installed across water treatment facilities under their control i.e. approximately 3,940 tonnes. This however, does not represent an annual demand as this material is replaced or regenerated on an ‘as required’ basis, with c. 224 tonnes replaced in 2016 across PPP and non-PPP sites and c. 117 tonnes replaced in 2017 at these sites, with 30 tonnes of PAC consumed annually at PPP sites. It is identified that virgin GAC used in water treatment can be expected to have a lifespan on 5 – 10 years, dependent on loading. It has also been identified that GAC at non-PPP sites is typically regenerated and this therefore does not represent a market for virgin material – the 180 tonnes replaced in 2016 is assumed to have been regenerated, while the 51 tonnes installed in 2017 represents ‘new’ material consumed. GAC used at PPP sites is identified as being replaced rather than being regenerated, with this material being disposed of to landfill. From a wastewater treatment treatment perspective, for PPP sites, c. 25 - 26 tonnes of GAC is consumed annually for odour control, with the activated carbon material utilised for incineration flue gas control assumed to relate primarily to the sludge thermal treatment facility in Belfast, with a c. 40 tonne per annum consumption identified60. 59
UK Energy from Waste Statistics, Tolvik C onsulting: http://www.tolvik.com/wp-content/uploads/Tolvik-UK-EfW-Statistics-2017.pdf https://www.niwater.com/belfast-sludge-incinerators/
60
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Information related to all 25 no. non-PPP wastewater facilities was not provided – however, with indicative figures provided for certain sites, it can be assumed that an annual GAC demand for odour control at these sites of c. 25 tonnes is a reasonable estimate. In estimating the annual demand of NIW for virgin activated carbon (GAC & PAC) and excluding material that may be regenerated, the following is considered a reasonable estimation, based on the information provided:
For water treatment, 120 tonnes of tonnes of GAC, 30 tonnes of tonnes of PAC For wastewater treatment, 50 tonnes of tonnes of GAC, 40 tonnes of tonnes of PAC
Other Sectors
In the absence of publicly available data, an assumption of activated carbon usage in sectors other than t han waste, water and wastewater was made on the same basis of the waste management sector i.e. on a population basis, which, when applied to the assumed demand for other applications for the Republic of 75 tonnes, suggests 30 tonnes as being a potential usage in other applications in Northern Ireland on an annual basis. Overall annual activated carbon demand in Northern Ireland is estimated as outlined in Table 14.
Table 14
Activated Carbon Demand in Northern Ireland
Sectors Waste Management Water Treatment Wastewater Treatment Others
Material PAC GAC PAC GAC PAC GAC PAC GAC
Summary Total
4.3.4
Tonnes
Comment 30 125 30 120 40 50 15 15
425
Assumed Based on reported information Based on reported information Assumed PAC 115; 310 GAC
Management of spent activated carbon
The management of spent activated carbon i.e. material whose adsorption capacity is exhausted is dependent on the means by which the material was utilised i.e. the condition of the material after use. Spent activated carbon may have adsorbed certain material that could quantify the spent material as being hazardous, and therefore require specialised hazardous waste management. Where utilised in flue gas cleaning operations, the activated carbon is captured as part of the flue gas residues, which are considered hazardous and are managed through export from Ireland to appropriate hazardous waste disposal facilities. Activated carbon utilised in odour control units at waste management facilities is not considered hazardous and can be manged either through landfilling or through processing at a composting facility. However, given that some activated carbon material can display self-heating properties, landfill facilities are often not keen to accept this material. IW have confirmed that the PAC utilised at their drinking water facilities is typically disposed of to landfill, while activated carbon used at wastewater facilities is identified as being managed as either a hazardous or nonhazardous material, dependent on its loading and specific application. While regeneration of spent activated carbon is a possibility, it is not currently offered by the majority of Irish based activated carbon suppliers, given the logistics associated with movement of this material and the fact
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that, once it is used and ‘intended or required to be discarded’ 61, it is considered a waste material and thus requires specific documentation and other control for its shipment. However, future developments at an Irish based facility, as outlined in Section 4.3.6 following, may provide a viable option for regeneration in Ireland in the future. 4.3.5
Quantification of Activated Carbon Market in Ireland
Based on values identified, assumed and estimated in the preceding sections, the annual activated carbon demand in Ireland is outlined in Table 15 following. Table 15
Activated Carbon Demand on the Island of Ireland
Material
4.3.6
Northern Ireland
Republic of Ireland
Tonnes
Totals
PAC
115
425
540
GAC
310
425
735
425
850
1,275
Valuation of Activated Carbon Market in Ireland
As a commodity with a wide range of applications and uses, the cost of activated carbon can vary significantly. However, in the course of discussions with suppliers and end users, a range of acti vated carbon costs have been identified, as outlined in Table 16 following which are considered to capture the types of material used in the sectors identified previously. It was also specifically identified in a number of instances that the price of activated carbon has increased significantly in the last 12 months due primarily to increased demand from China. Table 16
Cost range for Activated Carbon material Cost range (ex VAT) per tonne, €
Material
Typical Application
GAC
Odour/Air Treatment
2,000 – 2,500
PAC
Liquid phase applications
2,500 – 3,500
Very high prices can be encountered in i n some very specific, high end applications, with a range of €15,000 – 25,000 per tonne being cited – however, quantities of these materials are considered to be very small. Applying the value valu e ranges identified identi fied in Table 16 to the volumes identified previously, would suggest a market value range as identified in the following table.
61
As per definition of waste in Waste Framework Directive 2008/98/EC
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Table 17
Valuation of Activated Carbon market on the island of Ireland
Material
Total, t
Cost Range, €/t
Market Value Range, €
PAC
540
2,500 – 3,500
1,350,000 – 1,890,000
GAC
735
2,000 – 2,500
1,470,000 – 1,837,500
1,275
2,820,000 – 3,727,500
Other indirect costs are relevant to the management of activated carbon, in terms of transportation of same and management of the spent material. Values outlined in Table 17 are taken as being the delivered price, while w hile further costs are to be considered in terms of the management of spent carbon material and transportation of same. In terms of management of spent material, dependent on distances etc. haulage costs within Ireland tend to be in the range of €8 of €8 – 12/t62. Costs associated with spent activated carbon management vary depending on the application in which it was used – the following gate fee/treatment cost ranges apply based on the means of management:
4.3.7
Landfilling: Energy from waste: Composting: Hazardous waste management:
€120 – 150/t €100 – 120/t €50 – 70/t €600 – 650/t63
Other related developments regarding activated carbon
The potential for regeneration of activated carbon has been mentioned in preceding sections but is generally not provided as an option by activated carbon suppliers/distributors in the Republic of Ireland, due to the logistical costs and regulation associated with management of a waste material. As identified, activated carbon regeneration is undertaken by NIW in relation to the GAC material used at their water treatment facilities. However, as referenced earlier, Heat Systems Europe, a thermal processing equipment design and manufacturing company, is currently developing an activated carbon regeneration facility in Claremorris, Co. Mayo for the acceptance of spent granular activated carbon from a range of applications. This facility will operate under a waste facility permit from Mayo County Council, as the spent activated carbon input material will be considered a waste. Options for regeneration will include regeneration of a customer specific batch/load of activated carbon, with the material being returned to directly to them, or the addition of spent material to a generic pool for reactivation, when material does not need to be returned to the customer.
4.4 Summary of Activated Carbon Marketplace The activated carbon market place on the island of Ireland is well developed, with waste management, water treatment and wastewater treatment proving to be the primary sector of utilisation of this material. Existing, relatively mature supply chains are in place, with a number of Irish companies supplying activated carbon to the marketplace, in addition to the potential for direct supply from the UK or Europe. In the RoI, two approaches taken to quantify annual activated carbon demand broadly validate each other, with an annual demand of 850 tonnes estimated. In Northern Ireland, a quantity of half this value is estimated, at 425 tonnes per annum, with wit h an overall market value range of €2,820,000 – €3,727,500 applying. 62
Personal comms with haulier Personal comms with activated carbon supplier
63
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CASE STUDY NO.2
ACTIVATED CARBON END USER
Name:
Thorntons Recycling
Address:
Killeen Road Ballyfermot Dublin 10
Contact:
David Duff
Contact Email:
[email protected]
Thorntons Recycling was founded in 1979 by Padraig and Carmel Thornton and has grown into one of the largest waste management companies providing waste collection, recycling and recovery services predominately in Dublin, Meath, Kildare and Wicklow, while having the capabilities to operate nationally. The company also operates a liquid waste business and provides secure confidential shredding services to its customers. The customer base encompasses the domestic, public and private sectors, with annual sales in excess of €70 million. Thorntons Recycling continues to grow sustainably and currently has over 66,000 household customers along with over 5,000 commercial customers, delivering integrated solutions tailored to the needs of customers across a broad range of sectors from Pharmaceutical, Healthcare, Education, Manufacturing, Leisure, Construction and Household. It’s household customer base encompasses areas in South Dublin, Dublin City, Meath, Kildare and Wicklow, with a nationwide commercial customer base, with customers based from Cork to Donegal and Dublin to Galway. The company achieved an overall recycling rate of 88.13% in 2017 and currently the company employs over 505 staff. The company’s largest facility at Killeen Road, Dublin 10, which operates under licence W0044-02 from the Environmental Protection Agency and which accepts 250,000 tonnes of waste per annum, utilises an odour control unit (OCU) (shown above) for the capture and treatment of potentially odorous air from the processing buildings at the facility, in accordance with the conditions of the facility EPA licence. The facility processing buildings are kept under negative aeration i.e. air is constantly being removed from the areas using a suction fan and a network of pipework, which is directed to the OCU, where activated carbon is housed in three individual vessels. Odorous compounds are adsorbed by the activated carbon material as the process air passes through the OCU, such that the exhaust air then released to the atmosphere does not generate any odour nuisance. The activated carbon material used in the Thorntons Recycling OCU needs to display various properties appropriate to such a use including high durability to withstanding handling, low pressure drop characteristics in terms of air movement through the OCU vessels and a relatively high Iodine number (950mg/g) and surface area (1000 mg 2 /g). To date, Thorntons Recycling has typically used a coal-based steam activated material at a quantity of 30 - 40 tonnes per annum, dependent on the loading that the material has been exposed to etc. Spent activated carbon is managed in-house, as it is a suitable material for composting, and so it is sent to the Thorntons Recycling composting facility in Kilmainhamwood, Co. Meath. David Duff, Thorntons Recycling Environmental, Health & Safety Manager explains “From our perspective, the two most important factors in terms of activated carbon are firstly, being sure of the ready availability of a material of the specification required for our OCUs when we need it, and, secondly, like all things, cost is a factor in selecting an appropriate supplier. If an equivalent material was available that demonstrated the same performance characteristics as our current material and equivalent cost, which was perhaps a more sustainable and environmentally friendly material in terms of its carbon footprint, we would certainly be interested in considering such a material for use in our OCUs”.
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CASE STUDY NO.3
ACTIVATED CARBON SUPPLIER
Name: Name:
Nova-Q
Address:
Unit B21 KCR Industrial Estate Kimmage Road Lower Kimmage Dublin 12 www.nova-q.ie
Contact:
Julian Beatty
Contact Email:
[email protected]
Nova-Q (www.nova-q.ie (www.nova-q.ie ) ) is a specialist supplier of a range of products related to the agriculture, aquaculture, anaerobic digestion, water and waste treatment industries, who have built up a broad product portfolio through close collaboration with partners in Europe, Asia and North America. Nova-Q are one of the leading suppliers of activated carbon on the Irish market with their main markets being biological water treatment, chemical filtering fil tering and odour prevention. Nova-Q markets the CPL Carbon Link range of activated carbon, which provides a variety of granular, powdered and pelletised activated carbons of coal, coconut and wood-based origins, under the Filtracarb trademark for a range of applications such as water treatment, air and gas treatment, flue gas treatment, edible oil treatment (having FCC Certification) and gold recovery. The most common products are pellet, powder and granulated versions of coal or coconut based activated carbon. For vapour phased applications, it is common to add a catalyst or impregnant such as potassium carbonate or copper. Nova Q’s main market is the small to medium odour related applications, most commonly found in wastewater treatment and some food processing. In addition, Nova-Q has access to a range of activated carbon for specialist or high-grade applications where impregnated or catalytic carbon is required such as solvent recovery and CFC recycling in end of use refrigeration disposal. While their product suppliers can offer regeneration services, it is not a service currently offered by Nova Q for their Irish based customer. “While regeneration regeneratio n of activated carbon can offer o ffer significant signifi cant benefits to customers in terms of lower product costs, waste elimination and lower carbon footprint when compared to virgin material, the logistics of regeneration in terms of transportation of the spent material, which is considered a waste, outside of Ireland for regeneration doesn’t currently stack up” says Julian Beatty, Managing Director at Nova-Q. “We specialise in the supply su pply of activated carbon in quantities quant ities from f rom 50 kg up to 10 tonnes, across a range of sectors. In our experience, the waste management sector likely represents the largest single activated carbon user in Ireland, followed by the wastewater and water sectors. While activated carbon is utilised in a range of other sectors including pharmachem and food processing, the volumes used in these sectors are small compared to the waste, wastewater and water sectors. We also see activated carbon as being a material that is complementary to our wider range of biological products where we can apply advanced acclimatisation procedures to enhance how bacteria can deal with contaminants s uch as ammonia, sulphides, PAHs, petroleum hydrocarbons etc. in both water and specific remediation applications. In these instances, activated carbon is used as a final polishing step.”
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5 Carbon Profile The initial scope of this study required the estimation of the carbon footprint associated with the biochar and activated carbon markets in Ireland. As identified in previous sections, the biochar market is considered to be in a ‘fledgling’ phase and therefore an assessment of the current carbon footprint of the biochar market is not feasible. The activated carbon market, on the other hand, is quit e well developed in terms of a range of applications in which activated carbon is used in Ireland – however, the variation in possible applications as well as in the type and origination location of the source material, which cannot be readily identified, makes a single determination of its associated footprint a challenge. Therefore, this section attempts to develop a potential carbon footprint for biochar material produced and utilised in a particular manner that may be applicable in an Irish context in the future, should the market develop. Similarly, the carbon footprint for a particular application of activated carbon utilisation currently applied in Ireland and as identified in Case Study 2 of this report, is assessed in the following section. A ‘combined’ scenario is also developed that could reflect the production of activated carbon from biochar produced in an Irish context as outlined in the ‘biochar’ scenario as outlined in the following and utilised as per ‘activated carbon’ identified in the scenario following. The three scenarios developed for biochar and activated carbon are:
Biochar scenario - the production of 1,000 tonnes of biochar material in Ireland: from locally sourced forestry residues o with transportation of the inputs 50 km from point of origin (harvesting) o o processing using commercial scale slow pyrolysis incorporating heat recovery for feedstock drying transportation of biochar 30 km to point of use o utilisation as a soil amendment material o Activated carbon scenario – the production of 1,000 tonnes of activated carbon material in China: from coal and utilising steam activation o transportation of produced material by sea to Dublin, followed by 75km average of road o transportation to point of use installation and use in odour control units over a 12-month period, with each OCU operation utilising o a 50kW fan emptying of OCUs and transportation of spent material 50km average for management through o composting ‘Combined’ scenario – the production of activated carbon: o through steam activation of biochar produced as described in the ‘biochar’ scenario and utilised for odour control, with management of the spent material through composting, as outlined o in the ‘activated carbon’ scenario
Values applied to the carbon accounting of these scenarios in the following following sections are based on data derived from a desktop review of relevant journals and research publications, as specified in Appendix 1 or as identified in the following footnotes, and this should only be taken as an indicative suggestion of the relevant carbon footprint for each scenario. There are also a variety of up-steam and down-stream activities or related processes e.g. harvesting of forestry residues for biochar that could influence the carbon balance associated with each of the scenarios outlined, which are not included or assessed herein. A full life cycle assessment assessment (LCA) of various biochar and activate carbon applications, which is beyond the scope of this report, applied to a ‘system boundary’ (i.e. the extent/components of the scenario being assessed) related to Irish specific circumstances for each material, may be a beneficial future undertaking to inform further sectoral assessment/development.
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5.1 Biochar Scenario – Carbon Footprint For this scenario, the primary elements that comprise the system boundary of the scenario are:
Transportation Biochar production through slow pyrolysis Biochar utilisation
Emission impacts associated with the harvesting of source materials are not included, given that it is assumed the harvesting will occur in any event with the feedstock material being available for potential number of uses. Thus, this scenario ‘begins’ with the transportation of feedstock material to the pyrolysis facility. 5.1.1
Volume of feedstock required
In order to produce 1,000 tonnes of biochar material from a slow pyrolysis process, and assuming a biochar yield of approximately 30% from the slow pyrolysis of woody biomass as referenced in Roberts et al ., ., (28.8% for birch and 33% for spruce), it can be estimated that for the production of 1,000 tonnes of biochar, approximately 3,330 tonnes of woody biomass source material is required. It is assumed that feedstock material is chipped at point of harvesting using a shredder 64 and loaded directly to a walking floor trailer of delivery. Chipping at a rate of 350 m 3 /hr will require approximately 30 hours to produce 3,330 tonnes of woodchip feedstock, at a diesel consumption rate of 40l/hr 65, resulting in 1,200 litres of diesel consumption, with the assumption of a loading shovel operating for the same duration, with a fuel consumption of 20l/hr, resulting in 600 litres of diesel consumption.
5.1.2
Transportation of feedstock to pyrolysis facility
Assuming the transport of 3,330 tonnes of woody biomass feedstock for pyrolysis to a plant 50km from the t he point of feedstock harvesting, in walking floor trailers at 26 tonne payloads, requires 128 loads and equating to 166,500 tonne-kms66 (one-way only).
5.1.3
Processing using Pyrolysis
The assessment of the carbon performance of the pyrolysis system employed is dependent on a wide range of factors, including energy value of feedstock, pyrolysis technology configuration, means of syngas utilisation etc. and a detailed assessment of same in itself is a significant undertaking. For the purposes of this scenario, the following assumptions are made, informed by Roberts et al. (2009):
Initial pyrolysis kiln start-up consumes a small quantity of natural gas at 58 MJ/t feedstock Input energy value of feedstock divided approximately 50/50 between syngas generation and as retained in biochar produced Heat generated from syngas oxidation and applied through heat exchanger equates to 57% of syngas energy value
Therefore, on the basis that heat utilised from syngas oxidation offsets heat generation for feedstock drying that would otherwise be provided by an oil burner, the following carbon balance associated with the pyrolysis system is estimated.
64
https://www.komptech.com/fileadmin/komptech/brochures/Axtor_2017_EN.pdf https://www.komptechrental.com/fileadmin/komptech/magazines/Magazin_E__2018_1.pdf 66 1 tonne-km = transportation of one ton of freight one kilometre 65
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Table 18
Pyrolysis System Carbon Balance Feedstock Energy value
3,330 t @ 18MJ/kg (assumed) = 59,400 GJ/16500 MWh
Start-up energy (natural gas)
58 MJ x 3,330 t = 193 GJ/53.5MWh
consumption
Energy value retained within biochar
29,700 MJ/kg or 8250 MWh
Syngas Energy Value
29,700 MJ/kg or 8250 MWh
Useful heat generated by syngas oxidation
16,930 MJ/kg or 4702 MWh
Fuel oil emission per kWh
0.28 kgCO2eq67
Fuel oil offset value for syngas produced heat
1,316 t CO2eq
Less start up natural gas utilisation @ 0.2 kgCO2 eq per kWh
11 t CO2eq
Balance CO 2eq saving through syngas utilisation
1,305 t CO2eq
Consideration of loading of the produced biochar for consignment of this material to end application is also considered with an assumption of 25 hours operation of a loading shovel for the filling of a walking floor trailer, with a fuel consumption of 20l/hr, resulting in 500 litres of diesel consumption. 5.1.4
Transportation of biochar to end-use
A similar assumption is made for this t his step of the scenario in relation relatio n to transportation in that it is assumed that biochar material is transported to its end use location in walking floor trailer of 26 tonne payload – in practice, biochar material may well be consigned to varying end use locations in smaller loads by tractor and trail er. However, of the purpose of this indicative scenario, the assumption outlined is considered sufficient for transportation emission estimation. Transportation of 1,000 tonnes of biochar material produced from the pyrolysis facility a distance of 30km to the location of end point application requires 38 loads equates to 29,640 tonne-kms.
5.1.5
Biochar Utilisation as a soil amendment
As with assessing the performance of pyrolysis in terms of its carbon balance, the definitive attribution of the carbon performance of biochar as applied to soils is a subject worthy of detailed analysis and influenced by a range of considerations - this section attempts to only provide a high-level assessment of same in order to determine an indicative carbon balance which is assessed under three aspects:
Stable carbon in biochar applied to soils Improvement in the efficiency of fertiliser use Impact on soils N20/CH 4 emissions
Stable carbon in biochar applied to soils – soils – the carbon sequestration potential of biochar is ident ified as one of the main benefits of this material, and the recalcitrance of the biochar (i.e. the ability to resist degradation) when applied to soils is a factor for consideration in terms of assessing how much of the biochar applied to soils can be considered as being ‘sequestered’. Recalcitrance can be impact by a number of factors, not least the process temperature applied during pyrolysis, and the O/C and H/C ratios, as identified in Section 2.2.2 are important indicators as to an indication of the recalcitrance of any biochar. 67
https://www.volker-quaschning.de/datserv/CO2-spez/index_e.php
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Improvement of the efficiency of fertiliser value – value – the impact of biochar as applied to soils on improved fertiliser efficiency is well documented, with improved crop performance and a reduction in the amount of chemical fertilizers applied (Roberts et al ., ., 2009). Improvements in crop yield are also reported however, these are typically observed when biochar is applied to degraded soils, which is not generally the situation in Northern Europe and thus a demonstrable yield increase in an Irish context would not be expected. Impact on soils N2O/CH4 emissions – Biochar also display abilities to retain N compounds through adsorption
and thus affect the N cycle in soils, with a reduction in N20 resulting. The extent of this impact is influenced by the type of biochar, the soil type as well as the age of the biochar, where adsorption capacity of biochar applied to soil has been demonstrated to reduce over time68. Similarly, reduction in soil CH4 emissions have been reported for soils to which biochar has been applied, through the increased aeration of soil by improved soil structure, which also provides an improved habitat for methane consuming organisms. Note also, however than an increase in methane emission after biochar application to soil has also been reported in a number of papers (Brassard, 2016) Therefore, the quantification of a single definitive CO2eq value per tonne of biochar applied to soils is difficult to identify, given the wide range of factors that can influence this. However, for the purposes of this assessment we apply a sequestration benefit of 2.9 tonne CO2eq per 1 tonne of biochar application to soil, as per Verma et al . (2014) 69. 5.1.6
Scenario 1 - Carbon footprint assessment
The indicative carbon balance associated with each step in this scenario is outlined in Table 19 following.
Table 19
Carbon Balance for Scenario 1
Scenario Step
Applicable Values
Calculation methodology
Feedstock production (chipping)
1,800 L diesel consumption
1L diesel emits 7g of NOx and 2.6kg of CO 270 - 12.6 kg NOx71 & 4,680 kg CO2
8.43
Transportation to Pyrolysis facility
166,500 t-km
1 t-km = 68 g/CO2 72
11.3
Pyrolysis
As Table 15 above
As Table 15 above
Loading of biochar for consignment
500 L diesel consumption
As above – 3.5kg NOx & 1,300 kg CO2
Transportation to end use location
26,640
1 t-km = 68 g/CO2
Utilisation as amendment
1,000 t
1 tonne = 2.9 tonne sequestered
soil
Scenario Total
CO 2 eq, tonne
-1,305 2.34 1.8 -2,900 (Net saving)
- 4,181.13
5.2 Activated Carbon Carbon Scenario – Carbon Carbon Footprint Footprint As with the previous scenario, the activated carbon scenario is defined by a number of elements namely:
Production of activated carbon from coal Transportation
68
P. Brassard et al; Soil biochar amendment as a climate change mitigation tool: Key parameters and mechanisms involved, 2016 Verma et al: Thermochemical Transformation of Agro-biomass into Biochar: Simultaneous Carbon Sequestration and Soil Amendment – “biochar can have a carbon composition ≥60–80 %, which is equivalent to ≥2.20–2.94 ton CO2 sequestered/ton biochar” 70 https://www.volvotrucks.com/content/dam/volvo/volvo-trucks/markets/global/pdf/our-trucks/Emis_eng_10110_14001.pdf 71 NOx = 298 CO2 eq - https://climatechangeconnection.org/emissions/co2-equivalents/ 72 Measuring and Managing CO2 Emissions of European Chemical Transport, McKinnon; http://www.cefic.org/Documents/Media%20Center/News/McKinnon-Report-Final-230610.pdf 69
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Use in odour management application End management
Emission impacts associated with the generation of the source materials are not included, as it is assumed that is material is available and would be utilised util ised on other applications e.g. energy production, productio n, if not converted to activated carbon. The start point of the scenario is the commencement of activated carbon production from coal. 5.2.1
Volume of feedstock required & Activation Process
As determined in Ecoinvent 3.373, the production of 1 tonnes of granular activated carbon from coal require 3 tonnes of hard coal input, following a carbonisation process and partial gasification step, as the activation step. T he Ecoinvent dataset identifies the global warming potential of a ‘mini’ LCA of activated carbon production for coal as being 7.769 kg CO 2eq per kg of granular activated carbon, which is applied to this scenario. 5.2.2
Transportation by ship directly to Ireland
In practice, activated carbon may follow a circuitous route to its end use in Ireland, but for the purpose of this scenario assessment, we assume direct shipment from Chizou Port in China to Dublin Port, transported in 1 tonne bags by container shipping. The calculated shipping distance is identified as 11,974 nautical miles74 or 22,175 km, equating to 221,750 tonnekms, assuming 1,000 tonnes shipped in the same shipment. 5.2.3
Transportation by road to end use locations
As one location will not consume the identified identi fied 1,000 tonnes for use in OCUs, it is assumed that this material will be distributed to 25 no. locations throughout the country, with each using 40 tonnes over one year. An average of 75km distance for each facility from Dublin Port is assumed. As the material is delivered in 1 tonne bagged form, it is assumed that 50 loads are used to deliver the 1,000 tonnes of activated carbon material in 20 tonnes loads, which equates to 75,000 tonne-kms. 5.2.4
Energy consumption during Activated Carbon utilisation
The assumed application for which the activated carbon is used in this scenario i.e. as media within odour control units at a waste management or other industrial facilities, consumes electricity through the running of fan blowers that feed the OCUs. Assuming that 1,000 tonnes of activated act ivated carbon provide sufficient OCU media for 25 no. facilities over one year i.e.40 tonnes per facility per year, with each facility utilising a 50kW blower, results in a total 10,000 MWh 75 of electricity consumption per annum. It could be argued that the inclusion of the electricity consumed by the OCUs should not apply in this scenario in that the OCU (or a similar technology) would likely operate for their primary function in the event of activated carbon not being utilised. However, it can also be argued that the activated act ivated carbon would not be imported or possibly possi bly even produced without the demand for this material in such applications as OCUs, therefore for the purposes of this scenario analysis, we have therefore included this energy consumption.
73
https://www.ecoinvent.org/files/v3.3_-_cut-off_-_activated_carbon_production__granular_from_hard_coal_-_rer_ _activated_carbon__granular.pdf 74 http://ports.com/sea-route/#/?a=3201&b=15721&c=Dublin%20Port,%20Ireland&d=Anyer%20Terminal,%20Indonesia 75 Assume 8,000 hrs operation per b lower per annum
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5.2.5
Transportation by road to end management through composting
For the purposes of this scenario, it is assumed that 1,000 tonnes of spent activated carbon is suitable as a composting amendment material, as applied in Case Study 2 previously. No mass reduction or increase o ccurs when utilised as an odour management media, and the 1,000 tonnes of material is assumed to be composted at 5 different compost facilities through the country, located an average of 50 kms from each utilisation location, again assumed to be delivered in 20 tonne loads. Therefore, spent activated carbon travels 50,00 tonne-kms to composting facilities. 5.2.6
Management through composting
The composting process in itself produces CO2 emissions from the breakdown of the input material, resulting in mass reduction of the input material. It is assumed that each facility operates a fully enclosed tunnel composting system. Note this assessment does not considered any potential beneficial impact in terms of carbon emissions from resultant application of compost to lands.
5.2.7
Scenario 2 - Carbon footprint assessment
The indicative carbon balance associated with each step in this scenario is outlined in Table 20 following.
Table 20
Carbon Balance for Scenario 2
Scenario Step
Applicable Values
Calculation methodology
1,000 t
7.769 tCO2eq per t
221,750 tonne-kms
1 t-km = 8 g/CO2eq76
1.77
75,000 tonne-kms
1 t-km = 68 g/CO2eq77
5.1
Energy consumption during usage
10,000 MWh
0.47 kg CO2 per kwh of electricity generated78
Transportation to end management
50,000 tonne-kms
1 t-km = 68 g/CO2eq79
3.4
Management through composting
1,000 tonnes
118 kgCO2eq/tonne fresh input material 80
118
Activated carbon production Direct Shipment to Dublin Port Transportation to End use locations
Scenario Total
CO 2 eq, tonnes 7,769
(Net Burden)
4,700
12,597.27
5.3 ‘Combined’ Scenario Scenario - Carbon Footprint Footprint The third scenario explored presents the carbon footprint associated with production of activated carbon from biochar, produced as outlined in Scenario 1 i.e. produced in an Irish context from woody residues – in this scenario, the system boundary is the same as that as outlined in Scenario 1 until the point of biochar production, whereby the biochar produced by pyrolysis is subjected to steam activation and the activated carbon produced utilised in the application as outlined in Scenario 2 i.e. use in odour control. 76
Measuring and Managing CO 2 Emissions of European Chemical Transport, http://www.cefic.org/Documents/Media%20Center/News/McKinnon-Report-Final-230610.pdf 77 As above 78 https://www.seai.ie/resources/publications/Energy-Related-Emissions-in-Ireland-2016-report.pdf 79 As above 80 Greenhouse Gas Emissions from Composting and Anaerobic Digestion Plants; http://hss.ulb.uni-bonn.de/2012/3002/3002.pdf
McKinnon;
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Note that the yield of activated carbon produced from biochar through steam activation is 50% of the carbonised material, therefore only 500 tonnes of activated carbon would be produced from the 1,000 tonnes of biochar identified in Scenario 1. Taking the first three steps in Scenario 3 as being the same as Scenario 1 i.e. feedstock production, transportation to the pyrolysis facility and the pyrolysis process, the subsequent steps applicable to Scenario 3 are:
5.3.1
Steam activation Loading and transportation to end use Use in odour management application Management of spent material Steam Activation
Kim et al .81 describes an activation process where charcoal material is activated using steam in a rotary kiln, kiln , with a capacity of 8 tonnes per day, which produces 4 tonnes of activated carbon over an 8 hour and consumes 20 litres of kerosene per hour in the steam generator. Applying a similar activation process to the 1,000 tonnes of biochar produced from pyrolysis as described in Scenario 1 would result in th e consumption of 2,500 litres of kerosene over the duration taken to produce 500 tonnes of activated carbon. Note, no consideration is made in relation to the offoff gases produced during the activation process which in t heory can be captured and their energy value as fuel gases utilised, thus potentially providing a carbon saving if the result energy is applied within the activation or other processes.
5.3.2
Transportation
In a slight variance to Scenario 3, it is assumed that the activated carbon produced will be distributed to 25 no. locations throughout the country, with each using 25 tonnes over one year. An average of 75km distance for each facility from point of biochar production is assumed. It is also assumed that this material is delivered in 1 tonne bagged form, it is assumed that 50 loads are used to deliver the 500 tonnes of activated carbon material in 10 tonnes loads, which equates to 75,000 tonne-kms. 5.3.3
Use in odour management application
Keeping the same energy consumption assumption as Scenario 2, it is assumed that 500 tonnes of activated carbon provide sufficient OCU media for 25 no. facilities over one year i.e.25 tonnes per facility per year, with each facility utilising a 50kW blower, results in a total 10,000 MWh 82 of electricity consumption per annum (note that when compared to Scenario 2, the energy assumption will be impacted by the duration the blower operation rather than the quantity of activated carbon utilised in the process). 5.3.4
Transportation and management through composting
Similar assumptions are made as outlined in Scenario 2 i.e.:
the 500 tonnes of material is assumed to be composted at 5 different compost facilities through the country, located an average of 50 kms from each utilisation location assumed to be delivered in 10 tonne loads – therefore, spent activated carbon travels 50,000 tonne-kms to composting facilities. 500 tonnes of carbon managed through in-vessel composting with no consideration of any potential beneficial impact in terms of carbon emissions from resultant application of compost to lands.
81
Analysis of environmental impact of activated carbon production from wood waste, 2018; http://eeer.org/upload/eer-1530072686.pdf Assume 8,000 hrs operation per b lower per annum
82
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5.3.5
Scenario 3 - Carbon footprint assessment
The indicative carbon balance associated with each step in this scenario is outlined in Table 21 following. Table 21
Carbon Balance for Scenario 3
Scenario Step Feedstock production (chipping) Transportation to Pyrolysis facility Pyrolysis Steam Activation Transportation to End use locations Energy consumption during usage Transportation to end management Management through composting
Applicable Values
Calculation methodology
1,800 L diesel consumption
1L diesel emits 7g of NOx and 2.6kg of CO 283 - 12.6 kg NOx84 & 4,680 kg CO2
166,500 t-km
1 t-km = 68 g/CO2
As Table 15 above
As Table 15 above
2,500 L kerosene
Kerosene energy content = 44 MJ/kg 86 @ density of 0.81 kg/l = 35.6 MJ/L @ 2,500 L = 89,100 MJ @ 0.0715 kgCO2 /MJ /MJ87
6.3
75,000 tonne-kms
1 t-km = 68 g/CO2eq88
5.1
10,000 MWh
0.47 kg CO2 per kwh of electricity generated 89
50,000 tonne-kms
1 t-km = 68 g/CO2eq90
3.4
500 tonnes
118 kgCO2eq/tonne fresh input material 91
59
Scenario Total
CO 2 eq, tonnes 8.43
85
11.3 -1,305
(Net Burden)
4,700
3,488.53
Comparison with Scenario 2 A direct comparison between Scenario 2 & 3 is not possible based on th e information as presented in Tables 20 & 21, as Table 20 identifies the carbon burden associated with production of 1,000 tonnes of activated carbon, while Table 21 relates to 500 tonnes. In both tables, the most significant element of impact (positive or negative) is associated with the production of the materials and energy consumption during use – given that energy consumption in the identified application applicat ion i.e. odour control is modelled as being the same for both materials (and therefore is negated in any comparison) the primary area of comparison relates to the production processes of both materials – Table 22 present a comparison of both processes as identified in the previous scenarios, to allow a more direct comparison of both.
83
https://www.volvotrucks.com/content/dam/volvo/volvo-trucks/markets/global/pdf/our-trucks/Emis_eng_10110_14001.pdf NOx = 298 CO2 eq - https://climatechangeconnection.org/emissions/co2-equivalents/ 85 Measuring and Managing CO2 Emissions of European Chemical Transport, http://www.cefic.org/Documents/Media%20Center/News/McKinnon-Report-Final-230610.pdf https://www.seai.ie/resources/seai-statistics/conversion-factors/ 87 https://www.volker-quaschning.de/datserv/CO2-spez/index_e.php 88 As above 89 https://www.seai.ie/resources/publications/Energy-Related-Emissions-in-Ireland-2016-report.pdf 90 As above 91 Greenhouse Gas Emissions from Composting and Anaerobic Digestion Plants; http://hss.ulb.uni-bonn.de/2012/3002/3002.pdf 84
McKinnon;
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Table 22
Direct comparison of production processes
Activated carbon from biochar – Scenario 3
Activated carbon from coal – Scenario 2
Pyrolysis producing 1,000 t of biochar Steam activation of 1,000 tonnes of biochar, producing 500 tonnes of activated carbon
Production of 500 tonnes of activated carbon from coal
Total
- 1,305 t CO2 eq 6.3 t CO2eq - 1,298.7 t CO2 eq
3,884.5 t CO2eq
3,844.5 t CO2eq
5.4 Comparison of Carbon Footprints As would likely l ikely be expected when comparing these scenarios, the t he activated carbon production process displays a significant net carbon burden while the production and utilisation of locally sourced biochar displays a significant net saving, being associated primarily with pyrolysis energy offsets and sequestration and other benefits from land application. Common with most lifecycle assessments reviewed as part of this assessment, impacts associated with transport are minimal compared to the impact of production and utilisation or management. The offset of energy emissions i.e. a net benefit is a significant factor in determining the carbon balance of the biochar scenario and would also be if such an offset could be applied in activated carbon production – the biochar scenario applies a simple offset versus oil replacement, but a greater benefit could be realised in the event of combined heat and power application to this scenario. Likewise, a benefit from biochar application to soils is generally identified, with potential for others ‘cascade’ benefits to be realised in the event of biochar utilisation as a feed additive, for example. While coal is utilised as the feedstock material of the activated carbon scenario, it would likely be expected that a lower burden would be realised were a more sustainable biomass feedstock material to be utilised in activated carbon production, albeit a burden would still be expected given energy and other input and process emissions generated. This is somewhat demonstrated by the ‘combined’ scenario which provides perhaps the most useful information in terms of the carbon profile of an activated material produced from a biochar in an Irish context and, while indicating a net emissions burden, these are wholly related to the application in which the material is used and is not directly influenced by the material itself. Indeed, only a very minor emissions burden is associated with the conversion of biochar to an activated carbon material, which is associated with the consumption of fuel oil to power the steam generator used in the activation process in this scenario. In a real-world situation, it may well be the case that would it be possible to either utilise the energy produced from the pyrolysis process to drive the steam activation process or to use another renewable source, such that the net burden identified could be offset further. Therefore, in comparing Scenario 3 with Scenario 2, it is identified that the pro duction of activated carbon in Ireland from biochar produced from forestry residues, results in significantly reduced impacts in terms of emissions when compared to an activated carbon produced from coal in China i.e. -1,298.7 t CO2eq versus 3,844.5 t CO 2eq (as per Table 19).
In general, the assessment undertaken herein, while relatively high level and intended for illustrative purposes, reinforces the positive carbon saving impacts associated with biochar production, while also highlighting the potentially reduced impacts associated with ‘indigenous’ biochar-based activated carbon production versus the burdens associated with imported coal based activated carbon production and use.
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6 Summary & Conclusion This report has presented an overview of the current biochar and activated carbon marketplaces in Ireland, in order to inform considerations regarding the potential for activated carbon production from low value residual biomass in Ireland, as promoted by the RE-DIRECT project. It identifies a current biochar market in which very little commercial market activity has taken or is taking place, with very limited volumes being produced – however, a number of significant activities have been and are being undertaken in relation to research, technology and stakeholder representation, such that a degree of momentum has built in relation to biochar utilisation in Ireland, which could result in the development of an active biochar market, with the application of an appropriate stimulus/stimuli. A well develop activated carbon market is presented, with the t he majority proportion of o f activated carbon being used in three sectors, these being waste management, water treatment and wastewater treatment. Supply of activated carbon is through a number of distributors, with all activated carbon of various origin, type and end use, identified as being imported into Ireland. Overall, this assessment identifies an activated carbon market on the island of Ireland with an estimated annual demand of 1,275 tonnes and tonnes and a value of between €2.82 between €2.82 and €3.72 million. Standards related to both biochar and activated carbon are identified, with these being well developed for both material types. Those related to activated carbon are likely to be of most relevance in i n the event of activated carbon production from residual biomass, being related primarily to adsorption capacity, but also in terms of particle size and product durability and thus an activated carbon produced from biochar would need to display comparable specification in regard to these parameters. No capacity for the undertaking of relevant testing related to these standards is available in Irish laboratories and the absence of such capacity could provide an opportunity for such laboratories in the event of production of biochar and/or activated carbon in the future. A high level, indicative carbon balance was undertaken to compare the biochar and activated carbon markets – in the absence of an existing, developed biochar market in Ireland, a simple comparison of the carbon footprints of the separate production of biochar and activated carbon was undertaken, while a further scenario was developed to estimate the carbon impact of activated carbon production from biochar produced in Ireland, insofar as was possible. As would be expected, a net carbon benefit was w as identified in i n relation to biochar production pr oduction and utilisation u tilisation due to the energy offset associated with biochar production through pyrolysis and from the sequestration and other benefits associated with land application biochar. Similarly, an expected net carbon burden was identified for activated carbon, which, in the scenario reviewed, was produced from coal in China and shipped to Ireland for utilisation. It is also identified that the activation of a biochar produced in Ireland to create an activated carbon product, is likely to have only a minor carbon impact, as an additional processing step, when compared to the overall positive impact of biochar production, and therefore activated carbon produced in Ireland is likely to display significant carbon benefits when compared to, for example, a coal based material originating in China. While the primary focus of this study has been to describe and quantify the exiting biochar and activated carbon markets in Ireland, cognisance has also been given to the beneficial potenti al for biochar as a material to be utilised in a wider range of applications, and the broad market opportunities that these may represent in the event of the development of a strong biochar sector in Ireland. Biochar is identified as a material with potential for utilisation in a range of sectors, encompassing agriculture (as a feed additive, a co-fertilising product etc.), horticulture, landscaping, land conditioning, soil remediation and others, with these combined markets being worth in i n excess of €2 billion annually. While values of biochar can vary considerably dependent on production method, end use, etc. biochar is identified as a valuable product, with an approximate value of €1,750/tonne of €1,750/tonne identified, based on published values. Potential areas of focus for the development of the biochar sector in Ireland, as informed by engagement with stakeholders during the undertaking of this study, are considered to be as follows:
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The adoption and/or acknowledgement of the benefits of biochar in relevant national policy, legislation, support schemes, etc. - central to this is the ability to accurately quantify the value benefits arising from biochar use, and the development of such a mechanism to quantify these benefits that is supported by all stakeholders. The identification of ‘target applications’ where most value can be realised from the utilisation of biochar, be this as an activated carbon material, a feed additive, a fertilising co-product, a horticultural product, etc. in order that engagement, investment, marketing etc. can be focussed on the development of products relevant for these specific applications. The requirement for the ‘raising of the profile’ of biochar as a product amongst potential end users through, among other things, the continued undertaking of demonstration projects, such as the RE-DIRECT project to which this study is related, and the promotion of the findings of such studies. Continued collaboration between relevant stakeholders to build on the significant activities undertaken to date in the biochar sector, to utilise resources, experience, contacts, lobbying abilities etc. – the preparation of a Biochar Sectoral Development Plan or o r Action Group, led by an appropriate organisation organi sation and supported by relevant governmental department(s), that ties in the various activities and projects currently ongoing, could be a central ‘driver’ for sectoral development.
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APPENDIX 1 Technical Literature Review
TECHNICAL LITERATURE REVIEW OF SPECIFIC ASPECTS RELATED TO BIOCHAR & ACTIVATED CARBON PRODUCTION NOVEMBER 2018 PREPARED FOR:
Irish Bioenergy Association (IrBEA) & Western Development Commission (WDC)
PREPARED BY:
Miltcon Services Ltd.
REVISION:
For Issue
TABLE OF CONTENTS
1
Introduction ............................................................................................................. 3
2
Biochar & Activated Carbon Production ...................................................................... 4
3
2.1
Biochar Source Materials .................................................................................... 5
2.2
Activated Carbon Source Materials ...................................................................... 7
2.3
Impact of source materials on use/application ..................................................... 8
2.4
‘Carbonisation’ Processes.................................................................................. 13
2.5
Activation of Carbon......................................................................................... 24
Summary ............................................................................................................... 31
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1 Introduction Miltcon Services Ltd. has been retained by the Irish Bioenergy Association (IrBEA)(www.irbea.org (IrBEA)(www.irbea.org)) and the Western Development Commission (WDC)(www.wdc.ie (WDC)(www.wdc.ie)) to undertake a study to assess the current situation regarding the use of activated carbon and biochar on the island of Ireland. This study forms part of the input of IrBEA and the WDC to the RE-DIRECT project, an EU Interreg North West Europe Programme project, which promotes the efficient use of natural resources and materials by converting residual biomass into carbon products product s and activated carbon at regional, decentralised units. IrBEA and the WDC are two of eleven project partners from Ireland, the United Kingdom, France, Belgium and Germany. This report, included as Appendix 1 to the main Project Report and based on a review of available literature, is intended to provide a technical overview of the:
source materials used in biochar and activated carbon production the processes for biochar and activated carbon production
It is by no means intended to be exhaustive, as the technical aspects of biochar and activated carbon production are quite broad – instead, it attempts to present an overview of the aspects identified in order to inform further consideration of these factors in the main Project Report, as related to the biochar and activated carbon markets in Ireland.
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2 Biochar & Activated Carbon Production Biochar and activated carbon (along with charcoal), are classified as Pyrogenic Carbonaceous Material (PCM)2. They are the products of pyrolysis, where pyrolysis (a form of carbonisation) is “the thermo-chemical treatment of a feedstock in the strict absence of oxygen or any other additional oxidant ” (Hagemann et al ., ., 2018). All three products share similar chemical composition but have different chemical properties and therefore, distinct applications. Biochar is described as a “carbon-rich “carbon-rich material produced by burning organic biomass under complete absence (pyrolysis) or partial absence (gasification) of oxygen at temperatures ranging from 300 to 1000°C 1”, i.e. the result of pyrolysis of organic biomass. Biochar differs from charcoal in that (by definition) it refers to the deliberate application of the char material to the soil as a soil amendment, or for carbon sequestration2, whereas charcoal refers to the use of the char material as a source of fuel and for heating applications. As applications. As charcoal is not within the scope of this project, it is not considered further herein. Although the use of biochar as a soil amendment has received much interest in recent decades, the practice of adding pyrogenic carbon to soil has been practised in ancient civilizations across the world3. Much of the research on the topic has stemmed from the discovery that anthropogenic biochar carbon stocks, have remained in the low fertility Amazonian dark soils (so called “Terra “ Terra preta di Indio ”) ”) for over a thousand years subsequent to soil management practices in the region. Its application to weathered and nutrient leached soils had been carried out by South American populations for thousands of years, leading to total carbon values of up to 250 Mg C/ha/m – 2.5 times the typical values of the surrounding infertile tropical soils 4. Charcoal’s adsorptive properties were applied in ancient times – Hippocrates noted that unpleasant odours associated with an open wound could be reduced if charcoal dusting was applied to the area, but its industrial use occurred during the late 18th century as it was used to decolourise sugar in refineries as far back as 1794 5. Descriptions of biochar’s effects on the growth of vegetation were becoming evident by the mid-19th century, and used in horticultural contexts, with more detailed research on its effects on soil chemistry and seedling growth in the 20th century. The use of activated carbon in manufacturing can be traced back to the early 20th century with a patent registered by R.V. Ostrejko, which incorporated metal-chlorides and a carbonaceous material activated with steam or CO26. Although a widely accepted definition of activated carbon i s lacking (Hagemann et al ., ., 2018), activated carbon is described in the ‘Journal of Environmental Management’ as a “carbonaceous “carbonaceous solid with high micropores volume, well developed surface area and high adsorptive capacity ”. ”. It is produced from any carbon source (including sources of biochar) but is not limited to being derived from bio-organic sources, therefore it includes fossil and non-renewable sources. Activated carbon undergoes a process of ‘activation’, to be used as sorbent to remove contaminants from both gases and liquids. Hagemann et al. al. (2018) defined it as a “material “ material for contaminant sorption without exigencies in regard to the sustainability of its production nor to the fate of the carbon after its use ”. ”. The ability of charcoal to purify water has been known for millennia, but it wasn’t until the 19th century that charcoal began being optimised for the removal of specific contaminants. It was observed as early as 1862 that charcoal removed oxygen from air over the course a month7. Later experiments then removed adsorbed compounds from the charcoal surface through thermal activation, which left the material’s pores exposed and available for sorption i.e. “active” (Hagemann et al., al., 2018).
1
Science of The Total Environment, 2018. Biochar for Environmental Management: Science and Technology, Johannes Lehmann, Stephen M. Joseph (Eds.), (2009), Earthscan, London UK, 448 p Forest Policy and Economics 11 (2009) 535–536. 3 Schimmelpfennig S, Glaser B (2011) One step forward toward characterization: some important material properties to distinguish biochars. J Environ Qual 41 Qual 41:1001–1013. :1001–1013. 4 Lehmann, J., da Silva Jr., J.P., Steiner, C., Nehls, T., Zech, W. and Glaser, B. (2003a) Nutrient availability and leaching in an archaeological archaeological Anthrosol and a Ferralsol of the Central Amazon basin: basin: fertilizer, manure and charcoal amendments, Plant and Soil 249 Soil 249,, 343–357. 5 Source: https://www.donau-carbon.com/getattachment/76f78828-2139-496f-9b80-6b6b9bdc6acc/aktivkohle.aspx 6 Applications in Environmental Protection, Volume 120B 1 st Ed: A. Dabrowski (1999) Elsevier Science B.V. pp42 5. 7 Smith, A (1862) On the absorption of gases by charcoal — No. I. Proc. R. Soc. Lond ., ., 12, 12, 424–426. 2
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2.1 Biochar Source Materials While biochar can theoretically be made from any organic source of carbon, the feedstocks generally used in biochar production can be broadly split into two groups, woody biomass (derived from tree clippings and forestry residues etc.) and non-woody biomass (crop and grass residues, animal and municipal wastes etc.).
2.1.1 Woody Biomass Given that the feedstock type determines many of the physiochemical characteristics of biochar, producing biochar of required chemical and physical characteristics should take into consideration the feedstock type – not just the characteristics of pyrolysis. Biochars derived from woody biomass typically contain a higher carbon content than non-woody biomass. Wood that produces a char material with a high carbon content is favoured for the carbon matrix that forms during carbonisation, which gives the material its large surface area and its adsorptive properties. The pyrolysis of wood at 800°C for example, can produce a material with a carbon content of >80%, with the pyrolysis of wood at 400-500°C typically producing a biochar of 60-80% carbon. Other characteristics o f biochar from woody biomass include a comparatively low moisture and ash content (there is an inverse relationship between biochar ash and content carbon), a high calorific value and density, as well as a lower porosity, a lower mineral, nitrogen and sulphur content than non-woody biomass, such as manure, which has implications if the biochar is intended as a soil amendment8. A table outlining the ash content and elemental composition of different feedstock types is provided for comparison below in Error! Reference source not found. 9. Woody biomass feedstock can also be further categorised based on their proportions of different structural carbohydrates (primarily lignin, cellulose, hemicellulose), which contribute differently to the characteristics of the end biochar product – with Jafri et al. (2018) al. (2018) recommending feedstock biomass with a high lignin content, and Qambrania et al . (2017) also citing large particle size and low proportion of ash contributing to higher biochar yields. Source materials for woody biomass biochar production can include, inter alia :
Bamboo Tree bark Demolition wood Forestry residues Yard trimmings Ground nut shell (almond, coconut, walnut, macadamia etc.) Ground fruit pits or kernels (apricots) Hardwood Oak wood char Saw dust Softwood Walnut shells Willow wood Wood chips Wood pulp
8
Source: https://www.biochar-international.org/biochar-feedstocks/ Johannes Lehmann & Stephen M. Joseph (2009) Biochar for Environmental Management: Science and Technology.
9
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Table 1
Elemental composition of various biochar feedstock
Biochar feedstock
Bagasse Coconut coir Coconut shell Coir pith Corn cob Corn stalks Cotton gin waste Ground nut shell Millet husk Rice husk Rice straw Subabul wood Wheat straw Olive kernel Almond shell Forest residue Saw dust Waste wood Willow wood Demolition wood Straw Meat and bone meal Oak wood char
Ash content (wt %) 2.9 0.8 0.7 7.1 2.8 6.8 5.4 5.9 18.1 23.5 19.8 0.9 11.2 2.6 3.4 1.2 0.44 8.8 1.1 1.9 1.9 10.4
0.27
Al (mg/kg)
Ca
Fe
Mg
Na
K
P
Si
– 150 70 1700 – 1900 – 3600 – – – – 2500 18,000 5000 4900 9800 4900 20 480 5800 7600
1500 480 1500 3100 180 4700 3700 13,000 6300 1800 4800 6000 7700 97,000 80,000 130,000 170,000 130,000 3900 3600 8600 260,000
130 190 120 840 20 520 750 1100 1000 530 200 610 130 24,000 6100 10,000 29,000 10,000 30 350 3400 4900
6300 530 390 8100 1700 5900 4900 3500 11,000 1600 6300 1200 4300 20,000 14,000 19,000 27,000 19,000 360 420 3700 13,000
90 1800 1200 11,000 140 6500 1300 470 1400 130 5100 90 7900 7900 5500 4200 10,000 4200 150 670 3200 5800
2700 2400 2000 26000 9400 30 7100 18,000 3900 9100 5400 610 29,000 – – – – – 1400 750 22000 23,000
280 50 90 1200 450 2100 740 280 1300 340 750 100 210 – – – – – 340 60 600 100,000
17,000 3000 260 13,000 9900 13,000 13,000 11,000 150,000 220,000 170,000 200 44,000 – – – – – – – – –
1000
350,000
3400
16,000
6400
98,000
5400
4200
2.1.2 Non-woody Biomass Biochar derived from non-woody biomass is usually ch aracterised as having a high moisture moistu re and ash content, a (comparatively) lower calorific value, a low density and higher porosity (Jafri et al ., ., 2018). Source materials for non-woody biomass biochar production can include, inter alia:
Anaerobic digester sludge Animal meal Bagasse Bamboo Biosolids Cattle manure Charred barley straw Charred grass Coconut coir Coir pith Compost Corn cob Corn stover Cotton gin waste Distillers grain Food industry waste Girasol Horse manure Lop Maize Meat and bone meal Millet husk
Olive kernel Olive pomace Paper mill sludge Peanut shells Peas Pea-straw Pig manure Poultry litter Rapeseed cake Rice husks Rice straw Sewage sludge Sheep manure Soot Soybean cake Straw Sugar beet Sugar cane Vegetation fire residue Wheat Wheat straw
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Biochar produced from non-woody biomass typically consists of between 60-80% carbon if derived from corn stalks, with other husk material, tree bark, grasses and animal sludges producing a material of between 1560% carbon. Increasing the temperatures at which pyrolysis occurs, with a feedstock material that is low in ash, results in a higher surface area of the resultant biochar. Other characteristics of non-woody biomass include high ash and a low-medium mineral, nitrogen and sulphur content, cont ent, with a medium-high mineral, nitrogen and sulphur sul phur content for sludges. A characteristic of using non-woody biomass in the production of biochar, is the lower surface area and the resultant ash content of the char material – when compared to using a woody biomass feedstock. Oak wood biochar can produce a material with an ash content as low 0.27%, 0.44% for saw dust and 0.7% for coconut shell, with the use of corn stalks typically resulting in a material with an ash content of 2-8%, 10% for bone meal and up to 23.5% for rice husks. Non-woody biomass such as chicken litter, manures, pine biochar and corn stover carbonised at 400-500°C can result in biochar’s with a surface area of <50m2 /g, whereas low ash wood and nut biochar’s can result in surface areas of 350-500m 2 /g of material (Lehmann & Joseph, 2009). 2009). In biochars intended for land application, the nutrient profile of the resultant material is a key consideration. The mineral, nitrogen and sulphur content affect the biochar’s contribut ion to the soil’s nutrient retention, water wat er retention, the microfauna the soil can support, ability to improve yields and reduce greenhouse gas emissions. These nutrients typically remain low in wood and nut shell biochars (<5%), with stalk, husk and hull material with a mineral, nitrogen and sulphur content of between 5-20%, and sludge, litter or manure biochars having mineral, nitrogen and sulphur contents of between 20-70% (Lehmann & Joseph, 2009). It is important to note however that if a biochar has a high nutrient profile, this does not assure the availability of these nutrients in the soil.
2.2 Activated Carbon Carbon Source Materials Materials Like biochar, activated carbon is a pyrogenic carbonaceous material (PCM), but is not limited to being derived from bio-organic sources. This results in the source materials for activated carbon encompassing those for biochar (wood, sludge, food waste, garden waste) with the addition of source materials derived from coal, lignite, peat, petroleum, PVC, bone, used car tyres etc. (Tan et al., al., 2017). Any raw material with a high carbon content and low inorganic inorgani c compound content can be used as a feedstock for activated carbon with a list of common organic and inorganic source materials for activated carbon production provided below:
Activated carbon (recycled) Agroforestry Anaerobic digestion sludge Animal meal Bagasse Bamboo Barley Straw Biomass crops (herbaceous) Biomass crops (woody) Biosolids Bone Cardboard Cattle manure Cereals Charred barley straw Charred grass Coconut husk Coir pith Coal Compost
Millet husk Miscanthus Oak wood char Olive kernel Olive pomace Paper mill sludge Peanut shells Peas Peat Pea-straw Petroleum pitch (polymers) Pig manure Poplar Poultry litter PVC Rapeseed cake Rice Rice husks Saw dust Sewage sludge
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Corn cob Corn stover Cotton gin waste Demolition wood Dense refuse Distillers grain Peat Food waste Forest residue Girasol (sunflower) Green waste Nut shell Hardwood Horse manure Lignite Lop Maize Maize cobs Meat and bone meal
Sheep manure Softwood Soot Soybean cake Straw Sugar beet Sugarcane Switchgrass Tree bark Tyres Vegetation fire residue Wheat Wheat straw Whisky draff Wood chips Wood pulp Wood material Yard trimmings
A summary table of the characteristics of feedstock materials used in the manufacture of activated carbon– adapted from Musa Abubakar et al. (2016) al. (2016) – is shown below in Table 2.
Table 2
Characteristics of some materials used in the manufacture of Activated Carbon10. Carbon (mass %)
Volatiles (mass (mass %)
Density (cm3 g-1)
Ash (mass %)
Soft wood
40 – 45
55 – 60
0.4 – 0.5
0.3 – 1.1
Hard wood
40 – 42
55 – 60
0.55 – 0.8
0.3 – 1.2
Lignin
35 – 40
58 – 60
0.3 – 0.4
-
Nutshells
40 – 45
55 – 60
1.40
-
Lignite
55 – 70
25 – 40
1.0 – 1.35
5–6
Soft coal
65 – 80
20 – 30
1.25 – 1.5
2 – 12
Petroleum coke
70 – 85
15 – 20
1.35
0.5 – 0.7
Semi-hard coal
70 – 75
10 – 15
1.45
5 – 15
Hard coal
85 – 95
5 – 15
1.5 – 1.8
2 – 15
Raw material
Texture of AC
Soft, large-pore volume Soft, large-pore volume Soft, large-pore volume Hard, large micropore volume Hard, small-pore volume Medium-hard, medium-pore volume Medium-hard, medium-pore volume Hard, large-pore volume Hard, large-pore volume
2.3 Impact of source materials on use/applicatio use/application n As previously discussed, the feedstock used in pyrolysis, as well as the conditions of pyrolysis, will wi ll determine the elemental composition, the quantities of organic and inorganic compounds of the char material and its resultant properties. Carbon and nitrogen concentrations tend to increase after pyrolysis in plant feedstocks but decrease in mineral rich manures, as volatiles are lost.
10
Tadda, Musa Abubakar & Ahsan, Amimul & Shitu, Abubakar & Elsergany, Moetaz & Thirugnanasambantham, Arunkumar & Jose, Bipin & Razzaque, Md & Norsyahariati, Nik. (2016) A review on activated carbon: process, application and prospects, 2:7-13.
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Feedstocks high in nutrients such as in animal manure can result in biochars rich in potassium, nitr ogen, sulphur, and minerals when compared to woody and non-woody plant feedstocks which contain some inorganic compounds but are predominantly composed of sugars such as cellulose, hemicelluloses, and lignin – which are not optimal for creating a high porosity biochar. It is the presence of oxygen and carbon containing functional groups associated with the structural sugars in plant biomass in the form of cellulose, hemicelluloses, and lignin – and lipids and proteins present in animal wastes, that become active during pyrolysis and/or activation and give these biochars their capacity to remove organic compounds and heavy metals. The combination of the dissociation of oxygen from these functional groups, such as OH, COOH, and ketones – which gives biochars their negative atomic charge, and their ability to adsorb positively charged contaminants – the large surface area, carbon matrix, high degree of porosity (in non-plant biomass), that give biochar its adsorbing properties to heavy metals, polycyclic aromatic hydrocarbons, dioxins and furans in the environment11.
11
N.A. Qambrani et al. (2017) Renewable and Sustainable Energy Reviews, 79: 255–273
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Table 3 - Overview of the characteristics of biochars produced from different feedstocks – adapted from Qambrani
Reactor type
Reactor temperature (°C)
Heating time (°C min-1)
Residence time (h)
Biochar size (mm)
BET surface area (cm2 g-1)
Micropore volume (cm3 g-1)
pH
Mobile matter (%)
Fixed matter (%)
Anaerobic digestion residue
Homemade midscale low temperature rotary furnace
400
5
0.5
0.250.83
7.6
0
8.8
-
Apple branch
Furnace
400-800
10
10
0.5
11.9545.4
-
7-10
Bamboo
Furnace
450
-
-
1
10.2
-
Furnace
450
-
-
1
0.7
-
350
-
1
5
Cattle manure
Muffle furnace
250-550
16-19
1
Chicken litter
USIG skid mounted pyrolysis system
620
13
Coconut coir
-
250-600
-
Biomass feedstock
Brazilian pepper wood Broiler litter
Corn straw Dairy manure
Eucalyptus
Goat manure
Furnace with gas tight retort Homemade mid-scale lowtemperature rotary furnace Vertically fixed-bed reactor
et al.
(2017)
Elemental composition P
Ash (wt %)
Yield (%)
C
H
O
N
-
63.5
5.3
18.1
0.9
-
-
-
32.4-6.8
-
70.284.8
4.10.6
20.65.8
0.80.3
-
-
28.315.5
8.7
-
-
76.9
3.6
18.1
0.2
0.36
-
-
-
9.4
-
-
75.6
3.6
17.2
0.3
0.08
-
-
94
0
-
-
-
45.6
4
18.3
4.5
-
-
-
0.5
1.4-58.6
0-0.1
7.910.3
-
-
52.265.9
-
-
1.92.2
4500
8.618.6
-
2
-
-
-
-
51.1
8.2
41.5
1.2
0.7
2.8
-
-
1
0.5
1.7-299
-
-
-
-
57.283.8
5.32.6
3611.6
0.8
-
600
-
2
>1.5
13.1
-
9.5
-
-
35.9
1.6
1.9
0.4
2.5
350
2.5
2
-
1.6
-
9.2
53.5
23.2
55.8
4.3
18.7
2.6
400
5
0.5
0.250.83
10.4
-
7.5
-
-
77.8
5.4
18.3
0.4
400-800
-263.2
0.5
-
3.3-93.5
-
-
-
-
42.743.6
1.70.8
30.121.7
2.11.1
53.2
-
43-49
-
60.2
-
24.2
54.9
-
-
-
3.8-5
-
44.533.8
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Grass
Muffle furnace
200-600
-
1
0.3
3.3
-
-
-
23.667.6
47.289
7.12.5
45.17.6
0.61
-
Hardwood
-
450
-
<5s
<1.5
0.4
-
5.6
-
-
53.4
2.3
5.7
0.1
0.6
38.6
-
Hickory wood
Furnace
450
-
1
12.9
-
8
83.6
3.2
11.5
0.2
0.02
-
-
Human manure
Tube furnace
300-700
15
0.7
-
-
-
7.311.1
60.5-6.3
13.231.2
42.936.4
6.71.8
44.458.3
4.82.4
5.48.1
26.662.5
51.930.6
Miscanthus sacchariflorus
Lab scale SS reactor in furnace
300-600
10
1
-
0.6-381.5
0
8.310.1
75.8-1.5
53.888.6
68.590.7
5.52.3
25.76.7
0.30.4
-
2.22.7
53.888.6
Orange peel
Furnace
400-700
-
2
2
428-110.2
-
11.612.3
-
-
68.474.8
4.81.6
19.813.4
21.7
-
5-8.5
-
400
5
0.5
0.250.83
2.5
0.1
7.1
-
-
68.9
5.4
20.8
0.9
-
-
-
300
7
3
1
3.1
-
7.8
-
-
68.3
3.9
25.9
1.9
-
1.2
36.9
54.272.4
84.290.1
4.42.1
7.63.7
3.94.1
-
7.211.8
57.631.8
50.968.9
6.24.6
42.325.7
0.71.1
-
0.91.9
91.248.6
63.970.7 49.257.7
5.43.4 6.24.3
30.425.5 43.636.3
0.30.4
-
4.57.9
0.3
-
1-1.7
60.733.5 88.964.7
Palm bark
Peanut shells Pine needle Pine needle litters Pine pitch Pine wood shavings Poultry litter Poultry litter (pelletised) Rice husk
Homemade midscale lowtemperature rotary furnace Muffle furnace Muffle furnace Furnace Fluidized bed reactor Muffle furnace Furnace with gas tight retort Lindberg box furnace equipped with a retort Furnace
-
-
300-500
7
3
1
4.1-13.1
-
-
38.615.8
100-300
-
6
0.2
0.7-19.9
0
-
-
-
300-400
-
2s
0.4
2.9-4.8
-
-
-
-
150-250
5
6
0.2
1.8-5.9
-
-
-
-
350
2.5
2
-
3.9
-
8.7
19
42.3
51.1
3.8
15.6
4.5
-
30.7
54.3
350
-
-
0.3
1.1
-
8.7
36.7
-
46.1
3.7
8.6
4.9
2.94
35.9
72
350
25
4
0.5
27.8
-
8
-
-
38.6
-
-
0.4
0.26
-
-
Page 11
Rice straw Rubber wood sawdust Sludge Sludge Sow manure Soybean stover Sugarcane bagasse Sugarcane bagasse
Muffle furnace Fixed bed reactor (stainless steel) Furnace Fixed bed horizontal tubular reactor Muffle furnace Muffle furnace Furnace
Muffle furnace Vertically Swine fixed-bed manure reactor Furnace with Swine solid gas tight retort Furnace with Turkey gas tight litter retort Weaner Muffle manure furnace Muffle Wood furnace
100
5
6
0.2
-
-
-
-
-
37.3
2.4
40
1.8
-
18.5
-
450-850
-
1
2-3
-
-
-
-
-
82.393.4
3.21.1
14-0.5
0.40
-
14.520
41.928.9
400
-
2
2
126.4
-
6.4
-
-
8.5
1
6.4
0.3
-
83.7
300-700
10
-
-
-
5.312
33.815.8
9.1-6.8
25.620.2
2.60.5
8.3
3.31.2
-
52.872.5
72.352.4
300
26
2
<0.154
3.8
38.4
3.2
11.7
2.9
7931
43.9
60
300
7
3
1
5.6
-
7.3
46.3
38.8
68.8
4.3
25
1.9
-
10.4
37
450
-
-
0.5-1
13.6
-
9
-
-
78.6
3.5
15.5
0.9
-
-
-
300
-
6
0.2
43.9
-
-
-
-
69.5
4.1
24.8
1.6
-
0.3
-
400
-263.2
1
-
5.7
0
-
-
-
41.8
1
20.6
3.2
-
42.5
-
350
2.5
2
-
0.9
-
-
49.8
17.7
51.5
4.9
11.1
3.5
-
32.5
62.3
350
2.5
2
-
2.6
-
-
42.1
23.1
49.3
3.6
15.4
4.1
-
34.8
58.1
300
26
2
<0.154
3.8
-
-
38.7
2.9
10.4
2.7
8108
45.4
59.5
-
21.462.2
50.974.1
7-5
42.220.9
00.1
-
200-400
-
1
0.3
2.3-28.7
8.9
-
-
-
-
-
Page 12
The increase in the high heat value of some feedstocks (such as animal waste) after thermal conversion, offers the possibility of wet biomass being used to produce carbon dense biochar fuel or fertilizer, and nutrient rich liquids from low-grade feedstocks or waste. In two studies referenced in Qambrani et al . (2017), the thermal conversion of cow manure over 5–30 mins at 180–260°C, resulted in a 15% increase in the high heat value (HHV) from 19.1 to 22.1 MJ/kg after conversion, with a high nutrien t retention in the solid so lid biochar, with biochar energy values of over 25 MJ/kg achieved from the thermal conversion of poultry litter. Activated carbon derived from biochar has advantages over other activated carbons, in that the source material material can be low-cost (if from plant biomass or agricultural waste), sustainable, combustible emissions can be recovered, but may also have more limited applications due to its lower micropore volume than other activated carbons12. As with biochar, biochar, the type and and composition of the feedstock, the conditions under which the source material was modified (pyrolysis), as well as the method of activation determine the properties of the activated carbon – all of which can be modified to suit a desired application (water treatment, energy storage, carbon sequestration etc.)Error! Bookmark not defined.. Wood derived activated carbons exhibit larger pore sizes, which are preferred in processes for the removal or larger organic molecules and the removal of colour13, with the use of activated carbon from hard wood being favourable over soft woods due to its structural strength. Coconut shell derived activated carbons are widely used in adsorption of small organic molecules and disinfection, due to the large quantity of micro-pores on the material’s surface14. Crushed coconut shells and apricot pits being reported as resulting in the highest grades of activated carbons12. While biochar may be a more cost-effective cost-effect ive method for the adsorption of contaminants and in some cases may exceed the adsorption performance of activated carbon, biochar can take longer for adsorption, may require larger quantities, and can exhibit a less stable adsorption rate15. Coal based activated carbons exhibit a variety of pore sizes and high surface area, which make them suitable for the adsorption of a wide range of organic molecules 16.
2.4 ‘Carbonisation’ Processes Processes The initial production processes for biochar and charcoal are the same i.e. carbonisation. There are two main distinctions to be made between charcoal and biochar - both are pyrogenic carbonaceous materials i.e. a result of pyrolysis (a form of carbonisation), however biochar is typically produced for land application for agricultural or environmental purposes, whereas charcoal (like activated carbon), can be derived from the pyrolysis of nonrenewable animal sources such as bone, used car tyres, coal, as well as plant matter or animal waste (Lehmann & Joseph, 2009). Under the European Biochar Certificate (EBC) quality guidelines for biochar, a char material with a carbon content of below 50% cannot be classified as a biochar and should be classified under a broader term as a ‘Pyrogenic Carbonaceous Material (PCM)’ 17, whereas the ‘International Biochar Initiative’ (IBI) and the British ‘Biochar Quality Mandate’ (BQM) set a minimum organic carbon content of ≥10% ≥10% for classification as as a biochar. Activated carbon shares the initial process of carbonisation with charcoal and biochar, but with the additional step of activation of the charred material. The result of carbonisation and activation is called activated carbon, regardless of the char’s origin (waste tyres, coal, peat, bone, animal waste, plant biomass , biosolids etc.).
12
Khah, A.M., Ansari, R., (2009) Activated charcoal: preparation, characterization and applications: a review article. Int. J. Chemtech Res .
1, 859-864. 13 Source: https://www.wqa.org/Portals/0/Technical/Technical%20Fact%20Sheets/2016_GAC.pdf 14
Source: https://www.wqa.org/Portals/0/Technical/Technical%20Fact%20Sheets/2016_GAC.pdf Alhashimi HA, Aktas CB. (2017) Life cycle environmental and economic performance of biochar compared with activated carbon: a ;118:13–26. meta-analysis. Resour Conserv Recyl ;118:13–26. 16 Source: http://vertassets.blob.core.windows.net/download/a5c96ac8/a5c96ac8-87f9-4c44-83572d00b6ac4d8b/wp_adsorpreactindust15_zolt_e1.pdf 17 Source: http://www.european-biochar.org/biochar/media/doc/ebc-guidelines.pdf 15
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The conversion of biomass into biochar (carbonisation ) can be achieved through various thermal reactions. T his section explores the different methods of carbonisation of biomass, and how these processes affect the volume, structure and composition of the resultant biochar product, with a focus on slow pyrolysis due to biochar being the primary product of this process when compared to other carbonisation methods. A summary table of the different carbonisation processes – adapted from Cha et al . (2016) and Ahmed et al . (2016) – is shown below in Table 4.
Table 4
Comparison of carbonisation processes Temperature range (ºC)
Yield (%)
Residence time
Slow pyrolysis
100-1000
15-40
Mins to hrs
Fast pyrolysis
300-1000
10-25
<2s
Torrefaction Gasification Hyrdothermal Hyrdothermal carbonisation Flash carbonisation carbonisation
200-300 700-1500 175-300 300-600
61-77 ~10 30-72 37-50
Mins to hrs Seconds to mins 30min to 16h ~30min
Thermochemical Thermochem ical process
2.4.1
Heating rate
Slow (<10°C/min) Very fast (~1000°C/s) Slow (<10°C/min) Moderate-very fast Slow Slow
Carbon content (mass%)18 95
74 51–55 <70 ≈85
Pyrolysis
As most carbonisation of biomass for the production of biochar production is carried carr ied out o ut using u sing pyrolysis, our ou r discussion of the methods of carbonisation, as well as the technologies used to produce biochar will focus on this process. Pyrolysis is the thermal decomposition of biomass into solid, liquid and gaseous products in an anoxic (oxidant free) environment and can be carried out via two methods; fast pyrolysis and slow pyrolysis 24. The differences between these two methods are the temperature at which the process occurs and the time, resulting in differing proportions of the solid, liquid and gas products. The solid, liquid and gas products are referred to as char (and ash), biooil (and tar) and syngas (comprising H2, CO, CO2, H2O, CH4), respectively. The pyrolysis temperature, the feedstock residence time, heat transfer rate, and particle size offer differing yield proportions of these products depending on the desired outcome19 - with biochar yields inversely proportional to biogas yields, and with increases in pyrolysis temperature 20. Traditionally, studies conducted on the yields of pyrolysis have been focussed on the maximising proportions of bio-oil and biogas products from woody biomass (Jafri et al ., ., 2018). Figure 1 shows a simplified diagram of the process of pyrolysis. The feedstock material enters the reactor with biooil to initiate pyrolysis and the feedstock material carbonized. The char is separated from the biogas and biooil, which can be used to generate power or used as inputs to the pyrolysis process.
18
Mohammad Boshir Ahmed, John L. Zhou, Huu Hao Ngo, Wenshan Guo (2016) Insight into biochar properties and its cost analysis.
Biomass and Bioenergy , 84;76-86. 84;76-86. 19 Pyrolysis of Biomass for Power and Biochar (January2015) Source : http://www.pluschar.ie/wp-content/uploads/2017/01/PBX2-Main-Text-
Final-5-11.2.15-4.pdf J.S. Cha, S.H. Park, S.C. Jung, C. Ryu, J.K. Jeon, M.C. Shin, et al. (2016) al. (2016) Production and utilization of biochar: a review. J Ind Eng Chem , 40, pp. 1-15. 20
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Figure 1
Pyrolysis Process21
Biomass feedstock can also require pre-possessing depending on whether carbonisation is to occur under fast or slow pyrolysis, this ensures a uniform heating rate and more control over the carbonisation process. Fast Pyrolysis Fast pyrolysis is the rapid (over the course of seconds) thermal conversion of biomass into biochar, biooil and biogas with the objective of obtaining high yields of biooil22. The process involves higher temperatures than slow pyrolysis (500°C-1000°C), as well as higher heating rates, and can typically result in product yields of 75% biooil, 13% biogas and 12 biochar31. However, fast pyrolysis, requires that the feedstock particles are small, such as in a dust or a powder form, with particle size decreasing as the heating rate increases resulting in very fine biochar. Slow Pyrolysis Slow pyrolysis is the slow controlled thermal decomposition of the feedstock material with longer residence times (hours to days) than fast pyrolysis, at temperatures of between 300°C and 600°C, using a low heating rate (~10°C/min). This maximises the yield of the solid product i.e. biochar, with typical yields in the range of 20-40% of the weight of the original feedstock biomass24, with the remaining proportions made up of 35% biogas, and 30% biooil23. Slow pyrolysis does not require that particle sizes be small, as the heat transfer is allowed to occur slowly, so this process can accommodate branches and logs, demanding less processing and resulting in larger biochar fragments (Lehmann & Joseph, 2009). Yields of biochar from pyrolysis however are strongly dependent on the feedstock material used, the temperature pyrolysis is carried out at, the heating rate of the biomass material, as well as the physiochemical
21
Source: https://i0.wp.com/www.cleantechloops.com/wp-content/uploads/2012/06/biooil.png Assessment of the potential to produce biochar and its application to South African soils as a mitigation measure (2015) Depa rtment of Environmental Affairs, Pretoria, South Africa. 23 Roberts, K.G., Gloy, B. a., Joseph, S., Scott, N.R., Lehmann, J., (2010) Life cycle assessment of biochar systems: estimating the energetic, economic, and climate change potential. Environ. Sci. Technol. 44; 44; 827–833. 827–833. 22
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characteristics/properties of the biochar (surface area, porosity, structure)24. Differing feedstock properties such as calorific value, material moisture, ash, carbon, and mineral content affect biochar yields during pyrolysis. A review of the production of biochars carried out by Jafri et al ., ., (2018) found that for both woody and the nonwoody biochar, yields decreased with increasing pyrolysis temperature – with yields of biochar for pine sawdust in one study dropping from over 61% at 300°C, to less than 23% at 600°C 25. The review also described the effects of the rate of increase in temperature during pyrolysis, and found that when carried out at 550°C, differing yields of biochar were produced depending on whether the rate of temperature increase was 7, 15, 30 or 50°C/min. As mentioned above, two of the most important factors in determining the properties of the biochar product are the feedstock used, and the temperature of pyrolysis. The preferred properties are dependent on the end use of the biochar, with two of the most important characteristics being the surface area and the carbon content. For use as a soil fertiliser, as a fuel source (charcoal), or as a precursor for activated carbon, a high surface area and internal porosity is favoured. Biochars derived from grass feedstock and woody biomass at lower temperatures (450°C) exhibit l ower surface areas than woody biomass at higher temperatures (>500°C). This is caused by the collapse of the micropore structures at higher temperatures due to the release of volatile gases – which affect the end product density and internal porosity. This is not conserved as temperatures (600°C) continue to rise, as ash content begins to impede pore formation24. The temperature at which pyrolysis occurs also affects the characteristics of the biochar. The surface area, the pH, and the ion exchange capacity of the resultant biochar increase with higher pyrolysis temperatures26. For example, one study found that biochar produced at 450°C exhibited a surface area of 0.7–13.6 m 2 g −1, rising to 243.7–401.0 m 2 g−1 with an increase in temperature to 600°C27. From a literature review conducted by Arena et al. (2016), al. (2016), maximum yields of biochar are achieved with slow 28 pyrolysis at 500°C , with optimal temperatures and exposure times differing, dependent on the required carbon content, the surface area and the internal porosity. Figure 2 following shows the decline in biochar yields with increasing pyrolysis temperature. The losses of the char material occur due to the combustion of the fixed carbon, resulting in the emission of the carbon as CO 2.
24
N.Jafria, W.Y.Wong, V.Doshia, L.W.Yoona,K.H.Cheah (2018) A review on production and characterization of biochars for application in direct carbon fuel cells. Process Safety and Environmental Protection, 118 ;152-166. 118 ;152-166. 25 W.Shengsen, B. Gao, A.R. Zimmerman, Y. Li, M. Lena, W.G. Harris, K.W. Migliaccio (2015) Physicochemical and sorptive properties of biochars derived from woody and herbaceous biomass. Chemosphere , 134;257-262. 134;257-262. 26 J. Lehmann (2007) Bio-energy in the black. Front Ecol Environment , 5 (7);381-387. 27 Y. Yao, et al . (2012) Adsorption of sulfamethoxazole on biochar and its impact on reclaimed water irrigation. J Hazard Mater, 209;408209;408413. 28 N. Arena, J. Lee, R. Clift (2016) Life Cycle A ssessment of activated carbon production from coconut shells. J. shells. J. Clean. Prod ., ., 125;68-77. 125;68-77.
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Figure 2
2.4.2
Biochar yields decreasing with increasing temperature (Shengsen et al ., ., 2015)29.
Gasification
Gasification is a similar process to pyrolysis but is carried out in the partial presence of oxygen, at higher temperatures than pyrolysis (typically 700°C – 800°C) using steam, air, or an oxidising gas mixture (such as CO2), and is designed for the preferred production of biogas30. This reaction converts the char produced in pyrolysis and converts it mainly to gas. Yields of resultant products from gasification are typically 85% biogas (H2, CO, CO2, N2 etc.), 10% biochar and ash and 5% tar and biooil31. Gasifiers can be configured in a number of ways – as updraft, downdraft, fluidised bed or as entrained bed units, each with different benefits and constraints. A constraints. A detailed breakdown of gasifier technologies is contained in Lehmann & Joseph (2009) – which is summarised below.
Updraft Gasifiers – The process in an updraft gasifier resembles the process used in a charcoal kiln, but with increased production of gas due to more air being combusted, coming in through an inlet below the biochar with the feedstock being added from the top of the gasifier. This technology has the advantage of being low cost but produces larger quantities of tar as a by-product. Downdraft Gasifiers – Downdraft gasifiers reduce the tar produced in the reaction, by forcing the gas and fuel to move in the same direction, tars produced make contact with char at hot temperatures, causing tar volatilisation. This process requires higher maintenance as the properties of the fuel used must be regulated and causes the formation of ash.
Shengsen Wanga, Bin Gao, Andrew R.Zimmerman, Yuncong Li, Lena Ma, Willie G.Harris, Kati W.Migliaccio (2015) Physicochemical and 134:257-262. sorptive properties of biochars derived from woody and herbaceous biomass. Chemosphere 134:257-262. 30 Hagemann, N.; Spokas, K.; Schmidt, H.-P.; Kägi, R.; Böhler, M.A.; Bucheli, T.D. (2018) Activated Carbon, Biochar and Charcoal: Linkages and Synergies across Pyrogenic Carbon’s ABCs. Water , 10, 10, 182. 31 N.A. Qambrani, M.M. Rahman, S. Won, S. Shim, C. Ra (2017) Biochar properties and eco-friendly applications for climate change mitigation, waste management, and wastewater treatment: a review. Renew. Sust. Energ. Rev ., ., 79; 79; 255-273.
29
Page 17
Figure 3
4 common common forms forms of gasifier (updraft, downdraft, fluidised bed and entrained bed gasifiers)32
Fluidised Beds – In fluidised bed gasifiers, exiting gas moves through a turbulent mix of fuel parti culate matter and ash, with feedstock entering the process directly and reaching high temperatures rapidly. This enables the use of a wider range of feedstocks and the removal of settled ash, but at the cost of high levels of particulate matter in the exiting gas stream and the use of high-power gas blowers. Entrained Bed Gasifiers – In entrained-flow gasifiers, the feedstock and air, steam, or other oxidants are simultaneously added to the gasifier. This results in the air encompassing the feedstock particles in a turbulent flow at high temperatures and pressures, which causes rapid conversion of the feedstock (with residence times of seconds), allowing for t he use of a wide variety of feedstocks, and large input s. The process is characterised by high carbon conversion efficiencies (98-99.5%) that results in syngas
low in tar and ash, as the high temperatures convert the ash to a solid slag (metal oxides and silica). The higher the water content of the feedstock, the higher the H-to-C ratio of the resultant syngas products33. Parameters affecting the proportion of yields include the reaction temperature, reaction time, pressure, gasification agent type and quantity used, with temperature being reported as the most important factor in determining the proportions of H2, CO, C, CO2, CH4, tar and hydrocarbons34.
2.4.3
HTC /HTP
Hydrothermal carbonisation (HTC) or hydrothermal processing (HTP) is used to process biomass materials that have a high moisture content (sludge, (slu dge, manure, food waste), and where drying would normally be requir ed. The liquid matter is placed in a reactor under increasing temperatures and pressure to prevent the boiling of the
32
Source: http://www.biorootenergy.com/alcohol-solutions/gasification-incineration-whats-the-difference/ Source: https://www.netl.doe.gov/research/coal/energy-systems/gasification/gasifipedia/entrainedflow 34 Taba, L.E., Irfan, M.F., Daud, W.A.M.W., Chakrabarti, M.H. (2012) The effect of temperature on various parameters in coal, biomass 16(8);5584-5596. and CO-gasification: a review. Renew. Sust. Energy Rev . 16(8);5584-5596. 33
Page 18
liquid biomass (Lehmann & Joseph, 2009), with residence times of 5-10 hours for batch reactors and 6-12 hours in continuous reactors35. The process temperatures are kept to:
<250°C to favourably yield biochar, called hydrothermal carbonisation (HTC) 250°C to 400C for the yield of biooil, called hydrothermal liquefaction (HTL) >400°C for biogas, called hydrothermal gasification (HTG)
The product of this process is often referred to as ‘hydrochar’ (Cha et al ., ., 2016). Wet manure/biomass can also be converted into high-energy fuel and fertilizer at 180–300°C using hydrothermal carbonisation (HTC), that produces higher biochar (50–80%) and lower gas (2–5%) yields compared to dry pyrolysis, and results in higher minerals content such as phosphorus, nitrogen, sulphur in the resultant biochar (Qambrani et al ., ., 2017). Figure 4 presents an overview of the HTC/HTP process - once particles are crushed to a uniform size, the feedstock (slurry) is mixed in the continuous reactor with an oxidant (steam) under increasing temperature and pressure to ~200°C and ~20 MPa. The feedstock is added to the top of the reactor with, while the converted biomass is (which is of a higher density) sinks to the bottom of the reactor. Once th e pressure and temperatures are reduced, the products are dewatered, and pelletised (Lehmann & Joseph, 2009).
Figure 4
HTC/HTP process36
35
Source: https://www.researchgate.net/publication/264197007_INDUSTRIALSCALE_HYDROTHERMAL_CARBONIZATION_OF_WASTE_SLUDGE_MATERIALS_FOR_FUEL_PRODUCTION?_sg=nlnAEc_laPoRgJTmQdEJN WqoAqr_aUkI-FgMBLUBrU5TfSU6CEAWZytADMKGqdaThknABDoKEw 36 Source: https://tinyurl.com/y8h25znz
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2.4.4
Flash carbonisation
Flash carbonisation involves the ignition of biomass in a flash fire at 300– 600°C in a pressurised reactor for 30 min, converting roughly 40% of the biomass into biochar, with increasing pressure decreasing the time for carbonisation (Cha et al ., ., 2016). This allows for improved yields of biochar through the complete conversion of fixed carbon through the oxidation of combustible gases as opposed to the biochar itself. The process is suitable for woody and non-woody plant biomass and can be personalised to produce varying quantities of biogas and bio-oil (which can accumulate on the surface of the biochar) reducing emissions and allowing for the recovery of co-products.
Figure 5
Flash Carbonisation Process37
37
Source: http://the.honoluluadvertiser.com/dailypix/2007/Jul/28/M180782727.GIF
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2.4.5
Torrefaction
A process similar to pyrolysis (often called ‘mild pyrolysis’), torrefaction is used to prepare the biomass for combustion or gasification by increasing the calorific value, and improving its thermochemical properties by removing moisture, oxygen, and CO2, and slowly heating to 200-300°C in an oxygen poor environment. This step is often used as a preparatory step before gasification to increase the energy density of the biomass and reduce its weight (Cha et al ., ., 2016). It can be used to remove moisture from and increase the calorific content of biomass to be used as a fuel 38.
Figure 6
2.4.6
Flash Carbonisation Process39:
‘Low Tech’ Technologies for Biochar Production
There are a range of ‘low tech’ technologies and processes for the production of biochar, that are often utilised in developing countries. These technologies are discussed below, and figures showing their construction are shown in Figure 7. Pit and mound kilns are the most primitive kilns, they are low maintenance and low cost, consisting of a pit or mound of feedstock (usually stacks of wood) with soil to control air to, and heat loss from the process. They are widely used in developing countries, and offering 12.5-30%, and 2-42% char yields respectively. The use of brick or stone, metal and concrete is often used to more tightly control air and gaseous flow to improve char yields. A disadvantage to this process is the feedstock must be inputted (and the products discharged) in batches, with the use of continuous process ‘mult iple hearth kilns’ being a more recent innovation. This allows for continuous processing and offers higher efficiencies over batch kilns40.
38
Yong Yang Gan, Hwai Chyuan Ong, Pau Loke Show, Tau Chuan Ling ,Wei-Hsin Chen, Kai Ling Yu ,Rosazlin Abdullah (2018) Torrefaction 165; 152-162. of microalgal biochar as potential coal fuel and application as bio-adsorbent. Energy Conversion and Management, 165; 39 Source: https://www.pellet.org/images/stories/2012%20-%20wpac%20presentations%20part%20b.pdf 40 Johannes Lehmann & Stephen M. Joseph (2009) Biochar for E nvironmental Management: Science and Technology.
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An open source design kiln (developed by the Ithaka Institute), also provides a low-cost alternative to a mound kiln, with higher quality biochar produced. The Kon-Tiki kiln consists of a steel cone with an opening on the top of approximately 1.5m in diameter, the walls at a 63° slope – which ensures better compaction and maintenance of anoxic conditions, and the unit stands at 0.9m tall. The steel cone allows the heat energy to be contained more effectively when compared to the earthen walls of a pit kiln, allowing for more consistent heat distribution during pyrolysis and a more uniform resultant biochar. Following the low-cost production of high-quality char using this method, subsequent variations of the Kon-Tiki kiln have been developed across the world. Brick kilns are constructed from bricks and with two opposing openings to control air and feedstock input (see Figure), producing potentially higher yields (12.5–33% yields) and higher quality char (Lehmann & Joseph, 2009) than pit and mound kilns. The transportable metal kiln is composed of two stacked metal cylinders with a conical cover with four steam and smoke outlets (see Figure 7). It allows for improved yields and biochar quality (18.9 – 31.4% char) over its brick and pit counterparts as it allows for tighter control over the smoke coming out of the kiln, as well as the air going in. The chimney can be fitted to an afterburner to greatly reduce volatile organic compounds, particulate matter, and carbon monoxide emissions (Lehmann & Joseph, 2009). A multiple hearth kiln is is composed of a steel cylinder containing a series of rotary rotary hearths (shelves) mounted to the walls of the exterior shell. A series of ‘rabble’ arms which are fixed to a central rotating shaft move across the hearths, moving carbonised wood to openings where the material is brushed to a lower level. Air flows upward through the rotating central shaft and produced gases travel against the direction of flow of the biomass. This allows for a continuous multiple hearth kiln to produce 2.5t of biochar per hour. It allows for tight control of gas flow and retention time improving quality and yield, and can also be fitted with an afterburner to reduce emissions.
Figure 7
‘Low tech’ Biochar production processes
Pit / Mound Kiln
Kon Tiki Kiln
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Brick kiln
Continuous multiple hearth kiln
Transportable metal kiln
Missouri-type charcoal kiln
To assess the extent of use of different biochar production equipment, the International Biochar Initiative (IBI) surveyed its members in its ‘State of the Biochar Industry 2015’ report. Forty-six of the organisation’s biochar producers and sellers responded with the results shown in Figure 8.
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Figure 8
Range of technologies utilised for biochar production
2.5 Activation of of Carbon As discussed previously, activated carbon is differ entiated from biochar in two aspects; the range of feedstock materials it can be derived from is greater (including feedstock material from non-biological origin) and the process of activation that occurs after carbonisation in order to further enhance certain physical and chemical characteristics of the resultant material.
2.5.1
Activation Process
Activation involves changes to the carbonaceous material’s physical (surface area, internal structure, micro porosity) and chemical properties (functional groups, polarity), and removes the volatile compounds and tar formed in the char material’s pores during carbonisation. The micropores are then exposed and widened, increasing the porosity and adsorption capacity of the char. Activation allows for the increase in surface area (up to 3000 m2 /g) and micropore volume (1.2 cm3 /g)41 – depending on the source material used, the temperatures of activation (800 - 1000°C), and the exposure times42. Although high activation temperatures may increase the development of pores in the resultant activated carbon, it can also affect the activated carbon yield, as well as other chemical properties of the activated carbon such as the ash content, composition, surface chemistry and pH43 (Lehmann, 2007). There are two processes by which the pyrogenic carboniferous material (PCM) is ‘activated’, chemical activation, and physical (thermal) activation – both being the result of oxidation of the carbon material.
41
Perrin A, Celzard A, Albiniak A, Kaczmarczyk J, Mareˆche´ JF, Furdin G. (2004) NaOH activation of anthracites: effect of temperature on pore textures and methane storage ability. Carbon;42(14): 2855–66. 42 J.A. Menéndez-Díaz, I. Martín-Gullón (2006) Chapter 1 - Types of carbon adsorbents and their production Interface Sci. Technol ., ., 7:1-47. 43 J. Lehmann (2007) Bio-energy in the black. Front Ecol Environment , 5:7 pp381-387.
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Physical activation is is mainly carried out using steam, CO2 or ozone gas (Cha et al., 2016), al., 2016), while an oxidising agent is used in chemical activation , with the chosen method depending on the required carbon density, preferred activated carbon form (powdered or granular), and the feedstock used (Khah & Ansari, 2009).
Physical Activation Physical (thermal) activation involves the use of steam or gas at 800-1000°C (or microwaves) to oxidise the solid carbon residue, removing condensates, opening micropores and increasing the surface area of the activated carbon material (Hagemann et al ., ., 2018). The increase in surface area is achieved by volatilising partially combusted compounds and tars th at have formed on the surface and in the pores of the material during carbonisation, by increasing th e available pores, pore size and volume, the adsorption capacity of the material also increases (Khah & Ansari, 2009). Figure 9 shows the processes steam activation from a woody biomass source material. At first the wood is crushed and pre-treated at 200°C to remove any moisture or impurities in the wood, then carbonised at 600°C using a hot gas. The particles are then crushed and activated using steam at 900 – 1000°C. In more advanced facilities, the steam is produced from the heat generated during carbonisation. carbo nisation. The activated carbon is then crushed, homogenised and sorted using screen meshes according to size (which is dependent on the product end-use) and packaged for distribution.
Figure 9
Steam Carbon Activation44
44
Source: http://agnicarbon.in/process.html http://agnicarbon.in/process.html..
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Chemical Activation
In chemical activation, the activated carbon material is commonly sawdust or peat, and is permeated with a liquid activation agent - most commonly ZnCl2, KOH or H3PO4 but other activation agents include FeCl3, H2SO4, HCl, HNO3, NaOH, Na 2CO3 /K /K 2CO3, and urea (Hagemann et al ., ., 2018). As carbonisation and activation occur at the same time in chemical activation, as shown in Figure 10, the inorganic liquid activation agents degrade the organic molecules on the surface of the material being carbonised, preventing the deposition of hydrocarbons. Once complete, the oxidising agent is flushed with water, and the activation chemicals are recovered (Khah & Ansari, 2009). Chemical activation typically results in higher activation efficiencies than physical activation, but imposes a cost of chemicals, cost of recovery of chemicals and the corrosion of materials (Cha et al ., ., 2016). Figure 10 shows the processes of chemical activation from sawdust (a common chemically activated carbon source material). The sawdust is impregnated with the activation agent (H3PO4 in this scenario) during carbonisation in the depicted continuous rotary kiln. Once activated the activation agent is washed from the activated carbon and recovered. The activated carbon is then dried, crushed, homogenised and sorted using screen meshes according to size (which is dependent on the product end-use) and packaged for distribution.
Figure 10
Chemical Carbon Activation45
45
Source: http://agnicarbon.in/process.html
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2.5.2
Products of Carbon Activation i.e. ‘Activated Carbon’
Activated carbon can be produced in a number of forms, as outlined in the following.
Powdered Activated Carbons
Powdered Activated Carbons (PACs) are usually made from hard dense source materials such as coconut shells and fruit pits, with pore sizes as small as <3nm (Khah & Ansari, 2009), particle sizes of less than 0.18mm in diameter, are characterised by an extremely high surface area to volume ratio, which makes them effective for adsorption. The harder the material, the easier the recovery and reuse of the material, but the finer the activated carbon, the more difficult it is to recover. PACs are commonly used in exhaust gas treatment treat ment applications46, such as in flue gas treatment (mercury, dioxin and furan removal)47. PACs are also used in liquid phase applications, such as for removing toxic or organic compounds, dyes, tastes and odours, and are later removed by sedimentation or by passing through filter beds48, making it ideal for applications in the pharmaceutical, chemicals and food industry, drinking w ater treatment (chloramine removal), ground and surface water remediation, industrial and municipal wastewater treatment (sludge stabilisation), soil remediation, agricultural and industrial spill remediation. The PAC’s capacity for adsorption is indicated by its iodine number, the higher the iodine number the greater the capacity for the removal of a wide range of organic compounds. The specification of a range of Jacobi powdered activated carbons are outlined in Table 5 for comparison.
Granular Activated Carbons
Granular Activated Carbon (GACs) are used in both liquid and gas phase applications, as they can be produced to exhibit the highest porosity for adsorption of any known material (3,000m 2 /g)49. They form irregular particle shapes and range from 0.2 to 5mm in size, which allows for adsorption of a wide range of organic contaminants, such as aromatic solvents (benzenes, toluene), chlo rinated aromatics (PCBs), phenols, fuels (gasoline, kerosene, oil), polynuclear aromatics (PNAs), herbicides and pesticides (DDT, chlordane, aldrin etc.) 46. Variations in the specifications of the activated carbon make them applicable to differing uses. A table outlining the specification of a number of Jacobi granular activated carbons, produced by the manufacturer Jacobi, is provided in Table 5, with three products being applicable to water treatment applications, and one being use in the removal of hydrocarbons from steam – an application used in the petrochemicals and energy generation industries.
Table 5
Shows the specifications of a number of Jacobi branded granular activated carbons
Specifications
Iodine Number mg/g Moisture content % Total Ash % Wettability min % Hardness min % Surface area m²/g Methylene blue number ml/g or mg/g
Water treatment applications
Hydrocarbon removal
850 5 15 95 95 900
1000 5 13 95 95 1050
1100 5 15 99 1200
1000 5 1 98 1050
200
280
260
-
46
Source: https://www.chemviron.eu/products/activated-carbon/ Source: https://www.calgoncarbon.com/app/uploads/DS-WPC15-EIN-E1.pdf 48 Source: https://enva.com/activated-carbon-water-treatment/ 49 Source: http://vertassets.blob.core.windows.net/download/a5c96ac8/a5c96ac8-87f9-4c44-83572d00b6ac4d8b/wp_adsorpreactindust15_zolt_e1.pdf 47
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Total pore volume cm³/g Water soluble ash % Apparent density kg/m³ pH
0.88 0.2 510 8-11
1.04 0.2 480 8-11
320 -
535 5-7
They are commonly used in water treatment plants in filtration beds or in mobile filtration systems which ensures carbon saturation when compared with PACs whereby the solution requires recirculation and longer contact times50. They offer lower operational costs, as the adsorptive properties can be thermally restored through reactivation of the recovered spent carbon, and continually reused (a process more difficult in PACs). Granulated activated carbon is often used in de-chlorination during water treatment processes. It acts as a catalyst to remove the reactive oxygen from sodium hypochlorite (NaOCl) which is used in water disinfection and odour removal51 – leaving salt (NaCl).
Other Types
Extruded activated carbon Extruded (pelletised) activated carbons are made by compressing the activated carbon with a binding agent and into cylindrical shaped pieces 1 to 5mm in diameter. These are mainly used in heavy duty and gas phase applications, such as in catalytic converters to reduce automotive emissions52, because of their high mechanical strength, low dust content and low pressure drop53, and in the food industry because of its low dust content and its suitability in removing chlorine, hydrogen sulphide, and cyclohexanes.
Activated carbon fabrics Activated carbon can be weaved into a microporous carbon cloth with large surface area, making it highly effective at adsorbing both liquids and gases. Applications in chemical or biological weapons defence, health care (wound dressing, ostomy bags, antibacterial and antiviral) and environmental, industrial and manufacturing technology54.
Impregnated activated carbon Impregnated activated carbons have had a solution of another chemical applied to their surface and are specifically designed in order to optimise the sorption properties of the carbon for a particular contaminant55, typically used to remove gases through adsorption and chemisorption, that would otherwise be difficult to remove by adsorption alone. This give them a wide range of applications in industries; such as the food and drink industries (caffeine refining/decaffeination, decolorization, alcohol purification, fish farms, carbon dioxide scrubbers in fruit storage, PAH-separation in edible oils), water treatment (municipal and domestic water treatment, aquarium water treatment, swimming pool water conditioning), refining and purification industries (biodiesel refining, cabin air filters, chloramine removal, liquid flow purification, removal of oil vapours in compressed air, refining tobacco, treatment of carbonate, amine and glycol solutions)56. Applications for impregnated activated carbons include odour removal, the removal of sulphur from landfill, sewage and biogas, household water filters, mercury removal, gas purification, gas protection in laboratory fume huts and gas masks, and catalysis57.
50
Source: https://doi-org.ucd.idm.oclc.org/10.1016/j.jenvman.2017.02.042 Source: Lenntech - https://www.lenntech.com/processes/disinfection/chemical/disinfectants-sodium-hypochlorite.htm 52 Source: http://www.haycarb.com/activated-carbon 53 Source: Desotec - https://www.desotec.com/en/carbonology/carbonology-academy/extruded-activated-carbon-eac 54 Source: Calgoncarbon https://www.calgoncarbon.com/products/flexzorb/ 55 ., 7;235-240. K.D. Henning, S. Schäfer. (1993) Gas Sep. Purif ., 56 Source: Carbotech - https://www.carbotech.de/aktivkohle/?lang=en#granularactivatedcarbons 57 Source: https://www.desotec.com/en/carbonology/carbonology-academy/impregnated-activated-carbon-0 51
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Impregnation chemicals such as sulphur, cerium dioxide (removal of mercury), potassium iodide (removal of hydrogen sulphide, arsenic), potassium carbonate (for hydrogen chloride/fluoride, sulphur dioxide), and silver (in municipal water treatment) have all been reported to increase the activated carbon’s affinity for compounds of interest. Research into impregnated activated carbons is still ongoing, developing activated carbons of bespoke specifications, suited to the desired application. Figure 11 shows a scanning electron microscope images of an activated carbon with no added NaOH (top left), an activated carbon impregnated with a 2% NaOH solution (top right), a 4% NaOH solution (bottom left), a 10% NaOH solution (bottom right). Note how the solution of the NaOH increases the effective surface area of the material, allow for greater adsorption capacity.
Figure 11 220058.
Scanning electron electron image of chemically impregnated activated carbon carbon magnified x
Reactivated carbon
Some manufacturers of activated carbon also provide a r eactivation service, whereby activated carbon that t hat has 59 had its adsorptive capacity exhausted, can be reused . The spent carbon is heated at high temperatures in a furnace to vaporize the adsorbed compounds and restore the open pores of the original activated carbon material. This avoids the potentially high cost (depending on the contaminants) and liability associated with disposing of the material to landfill, costs typically 20-40% less than virgin activated carbon, and only generates about
58
Source: http://www.rpe.org.in/viewimage.asp?img=RadiatProtEnviron_2014_37_3_179_154882_f5.jpg Source: https://www.calgoncarbon.com/app/uploads/CC-Corp-Brochure-ENG.pdf
59
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20% of the greenhouse gas emissions produced in the manufacturing of virgin activated carbon60. The activated carbon is however, less effective (80% - 95% of the original adsorptive capacity) and may contain toxic inorganic compounds61. Regeneration (using steam or chemicals) follows the same prin ciple as reactivation, however it is used in the recovery and reuse of the adsorbate.
60
Source:http://vertassets.blob.core.windows.net/download/a5c96ac8/a5c96ac8-87f9-4c44-8357Source:http://vertassets.blob.core.windows.net/download/a5c96ac8/a5c96ac8-87f9-4c44-83572d00b6ac4d8b/wp_adsorpreactindust15_zolt_e1.pdf 61 Source: https://www.wqa.org/Portals/0/Technical/Technical%20Fact%20Sheets/2016_GAC.pdf
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3 Summary Biochar and activated carbon are both the solid products of pyrolysis i.e. the carbonisation of a feedstock material in anoxic conditions, as such are classified as pyrogenic carbonaceous materials (PCM). Where the two materials differ is in terms of the sources the carbon containing material can be sour ced from, and their resultant properties. Biochar can be produced from any bio-organic source of carbon, generally categorised as being either ‘woody’ (wood, branches, tree clippings, forest residues) or ‘non-woody’ biomass (crop residues, animal and municipal wastes). Biochar is characterised by a high micropore volume and surface area, with the presence of oxygen containing functional groups on its surface, which give the biochar a high adsorptive capacity. Where activated carbon differs from biochar, is in the further processing of the PCM via ‘activation’ to produce ‘activated carbon’ (discussed below), and that it can be produced from the same bio-organic carbon sources as biochar but including fossil and non-renewable source materials – such as used car tyres, animal bone, peat, and coal. Biochar and activated carbon both undergo the same initial production processes i.e. carbonisation, which can be achieved through by pyrolysis (fast/slow), gasification, torrefaction, hydrothermal carbonisation, and flash carbonisation. These reactions produce varying proportions of the solid, liquid and gas products yielded, dependent on the reaction conditions conditi ons (temperature, exposure time, oxygen level). Slow pyrol ysis is the favoured reaction process in the production of biochar due to its higher yield when compared to other carbonisation reactions. Biochar yields are generally inversely proportional to syngas yields, and with increases in pyrolysis temperature. Slow pyrolysis is generally characterised by long residence times of the feedstock in the kiln (hours to days), and at temperatures of between 300-600°C, and at low heating rate (~10°C/min). Typical yields range from 20-40% of the weight of the original feedstock biomass, with the remaining proportions made up of syngas and bio-oil. After the process of carbonisation, the char material can be activated to further develop the materials physical (surface area, internal structure, micro-porosity) and chemical (functional groups, polarity) properties. There are two processes by which a char material is activated; chemical activation (oxidising agent such as ZnCl2, KOH or H3PO4), and physical (steam, CO2 or O 3) activation, both of which remove volatile compounds and tar which have formed in the pores of the char during carbonisation. The removal of these compounds effectively increases the porosity and available surface area of the material, resulting in a higher adsorption capacity. The method of activation is dependent on the desired properties of the resultant activated carbon, and the feedstock available. Commercially available activated carbons are predominantly found in two forms, granular activated carbon (GAC), and powdered activated carbon (PAC) – with extruded (pelletised), impregnated and textile activated carbons also available for more bespoke applications. The form of activated carbon products are altered to fit the desired (durability, recovery, surface area etc.). The end use of the biochar and activated carbon product is decisive in selecting the appropriate feedstock, the method of carbonisation, and the method of activation. Factors which should be considered in producing an activated carbon of desired characteristics and yield are the pyrolysis conditions (temperature, residence time, heat transfer rate, particle size), and the feedstock type.
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APPENDIX 2 Activated Carbon Carbon Test Methods Methods
DOCUMENT NUMBER
STANDARD DOCUMENT TITLE
American Standard Testing Testing Method D1203-16 D1762-84 D2652-11 D2854-09 D2862-16 D2866-11 D2867-17 D3466-06 D3467-01 D3802-79 D3803-91 D3838-05 D3860-98 D4069-95 D4373-14 D4607-94 D5029-98 D5158-98 D5159-91 D5160-95 D5228-92 D5742-95 D5832-98 D5919-96 D6385-99 D6586-00 D6646-01 D6647-01 D6781-02 D6851-02 D8176-18 E1568-13
Standard Test Methods for Volatile Loss from Plastics Using Activated Carbon Methods Standard Test Method for Chemical Analysis of Wood Charcoal Standard Terminology Relating to Activated Carbon Standard Test Method for Apparent Density of Activated Carbon Standard Test Method for Particle Size Distribution of Granular Activated Carbon Standard Test Method for Total Ash Content of Activated Carbon Standard Test Method for Moisture in Activated Carbon Standard Test Method for Ignition Temperature of Activated Carbon Standard Test Method for Carbon Tetrachloride (CTC) Activity of Activated Carbon Standard Test Method for Ball-Pan Hardness of Activated Carbon Standard Test Method for Nuclear Grade Activated Carbon Standard Test Method for pH of Activated Carbon Standard Practice for Determination of Adsorptive Capacity of Activated Carbon by Aqueous Phase Isotherm Technique Standard Specification for Impregnated Activated Carbon Used to Remove Gaseous Radio-Iodines from Gas Streams Standard Test Method for Rapid Determination of Carbonate Content of Soils Standard Test Method for the Determination of Iodine Number of Activated Carbon Standard Test Method for Water Solubles in Activated Carbon Standard Test Method for Determination of the Particle Size of Powdered Activated Carbon by Air Jet Sieving Standard Test Method for Dusting Attrition of Granular Activated Carbon Standard Guide for Gas-Phase Adsorption Testing of Activated Carbon Standard Test Method for Determination of the Butane Working Capacity of Activated Carbon Standard Test Method for the Butane Activity of Activated Carbon Standard Test Method for Volatile Matter Content of Activated Carbon Samples Standard Practice for the Determination of Adsorptive Capacity of Activated Carbon by a Micro-Isotherm Technique for Adsorbates at ppb Concentrations Standard Test Method for Determining Acid Extractable Content in Activated Carbon by Ashing Standard Practice for the Prediction of Contaminant Adsorption on GAC in Aqueous Systems using Rapid Small-Scale Column Tests Standard test Method for determination of the Accelerated Hydrogen Sulfide Breakthrough Capacity of Granular and palletized Activated Carbon Standard Test Method for Determination of Acid Soluble Iron via Atomic Absorption Standard Guide for Carbon Reactivation Standard Test Method for Determination of Contact pH with Activated Carbon Standard Test Method for Mechanically Tapped Density of Activated Carbon (Powdered and Fine Mesh) Standard Test Method for Determination of Gold in Activated Carbon by Fire Assay Gravimetry
American Water Work Association Association (AWWA)- Testing Standards Standards AWWA B600-16 B600-16 AWWA B604-18 B604-18 AWWA B605-99 B605-99
Powdered Activated Carbon Granular Activated Carbon Reactivation of Granular Activated Carbon
ISO/EN/BS Testing Standard Methods BS EN 12903:2009 BS EN 12915-1:2009 12915-1:2009 BS EN 12915-1:2009 12915-1:2009 BS EN 12915-2:2009 12915-2:2009 BS EN 15799:2010 BS ISO 21340:2017 ISO 21340:2017
Products used for the treatment of water intended for human consumption. Powdered activated carbon. Products used for the treatment of water intended for human consumption. Granular activated carbon. Virgin granular activated carbon Products used for the treatment of water intended for human consumption. Granular activated carbon. Virgin granular activated carbon Products used for the treatment of water intended for human consumption. Granular activated carbon. Reactivated granular activated carbon Products used for treatment of swimming pool water. Powdered activated carbon. Test methods for fibrous activated carbon Test methods for fibrous activated carbon, including specific surface area, pore volume, fibre and sheet properties, mass loss on drying, pH value, total ash content, and performance for toluene adsorption, methylene blue adsorption and iodine adsorption.
