University of Mauritius Faculty of Engineering Department of Chemical Engineering Chemical and Environmental Engineering Level 4 Year 2015/2016 Name: Soomaree Keshav ID: 1114132 Title of dissertation: Production of bioplastics Code: AKR 5 Supervisor: Mr A K Ragen
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Table of Contents Table of Contents ............................................... .............................................................................. ..................................................ii ...................ii List of Tables Tables …………………………………………………………………....vi …………………………………………………………………....vi List of Figures Figures …………………………………………………………………...viii …………………………………………………………………...viii Acknowledgment Acknowledgment ………………………………………………………………..xi ………………………………………………………………..xi Declaration form ………………………………………………………………...xii ………………………………………………………………...xii Abstr act act ………………………………………………………………………….xiii ………………………………………………………………………….xiii List of Abbreviations Abbreviations …………………………………………………………… ……………………………………………………………xvi xvi List of Tables .................................. ................................................... .................................. .................................. .................................. ...................... ..... vi List of Figures ................................... .................................................... ................................... ................................... .................................. ................... vii List of Abbreviations Abbreviations ................................. .................................................. .................................. .................................. ........................... .......... xii Chapter 1:
Introduction ................................ ................................................. .................................. .................................. ......................14 .....14
1.1 Background.................. Background.................................... ................................... .................................. .................................. ............................14 ...........14 1.2 An overview on plastics ................................. .................................................. ................................... ............................14 ..........14 1.3 Plastics in Mauritius .................................... ..................................................... ................................... ...............................15 .............15 1.4 Production of plastics ....................... ........................................ .................................. .................................. .........................16 ........16 1.5 Plastic Carry Bags .................................. ................................................... .................................. ................................. ...................16 ...16 1.6 Objectives of the project........................ project.......................................... ................................... .................................. ...................17 ..17 1.7 Structure of the report.................................. ................................................... ................................... ...............................17 .............17 Chapter 2:
Literature Review......................... Review........................................... ................................... .................................. ...................19 ..19
2.1 Types of plastics ............................... ................................................ .................................. .................................. .........................19 ........19 2.2 Degradable plastics......................................... .......................................................... ................................... ............................20 ..........20 2.2.1
Plastics Codes .................................. .................................................. .................................. ..................................20 ................20
2.2.2
Production of degradable plastics ................................ ................................................. ......................23 .....23
2.2.3
Biodegradable plastic additives ........................................ .........................................................24 .................24
2.3 Biodegradable Biodegradable plastics............................................. .............................................................. .................................. ...................24 ..24 2.3.1
Classification Classification of biodegradable plastics .................................. ............................................25 ..........25 ii
Table of Contents Table of Contents ............................................... .............................................................................. ..................................................ii ...................ii List of Tables Tables …………………………………………………………………....vi …………………………………………………………………....vi List of Figures Figures …………………………………………………………………...viii …………………………………………………………………...viii Acknowledgment Acknowledgment ………………………………………………………………..xi ………………………………………………………………..xi Declaration form ………………………………………………………………...xii ………………………………………………………………...xii Abstr act act ………………………………………………………………………….xiii ………………………………………………………………………….xiii List of Abbreviations Abbreviations …………………………………………………………… ……………………………………………………………xvi xvi List of Tables .................................. ................................................... .................................. .................................. .................................. ...................... ..... vi List of Figures ................................... .................................................... ................................... ................................... .................................. ................... vii List of Abbreviations Abbreviations ................................. .................................................. .................................. .................................. ........................... .......... xii Chapter 1:
Introduction ................................ ................................................. .................................. .................................. ......................14 .....14
1.1 Background.................. Background.................................... ................................... .................................. .................................. ............................14 ...........14 1.2 An overview on plastics ................................. .................................................. ................................... ............................14 ..........14 1.3 Plastics in Mauritius .................................... ..................................................... ................................... ...............................15 .............15 1.4 Production of plastics ....................... ........................................ .................................. .................................. .........................16 ........16 1.5 Plastic Carry Bags .................................. ................................................... .................................. ................................. ...................16 ...16 1.6 Objectives of the project........................ project.......................................... ................................... .................................. ...................17 ..17 1.7 Structure of the report.................................. ................................................... ................................... ...............................17 .............17 Chapter 2:
Literature Review......................... Review........................................... ................................... .................................. ...................19 ..19
2.1 Types of plastics ............................... ................................................ .................................. .................................. .........................19 ........19 2.2 Degradable plastics......................................... .......................................................... ................................... ............................20 ..........20 2.2.1
Plastics Codes .................................. .................................................. .................................. ..................................20 ................20
2.2.2
Production of degradable plastics ................................ ................................................. ......................23 .....23
2.2.3
Biodegradable plastic additives ........................................ .........................................................24 .................24
2.3 Biodegradable Biodegradable plastics............................................. .............................................................. .................................. ...................24 ..24 2.3.1
Classification Classification of biodegradable plastics .................................. ............................................25 ..........25 ii
2.4 Starch based plastic ................................................. .................................................................. .................................. ...................26 ..26 2.4.1
Starch ................................... .................................................... .................................. .................................. ............................27 ...........27
2.4.2
Characteristics Characteristics of starch ........................... ............................................ .................................. .........................27 ........27
2.4.3
Different types of starch sources ................................. .................................................. ......................27 .....27
2.4.4
Properties exhibited by starch during polymer synthesis ..................28 ..................28
2.5 Comparison Comparison study ................................ ................................................. .................................. .................................. ......................29 .....29 2.5.1
Advantages of degradable plastics and starch-based plastics ............29
2.5.2
Disadvantages of degradable plastics and starch-based plastics .......30
2.6 Starch based polymer and plastic plant design ...........................................31 ...........................................31 2.6.1
Extraction of starch from potato ....................................... ........................................................31 .................31
2.6.2
The biodegradable polymer production from the starch ...................32 ...................32
2.6.3
The processing of starch-based starch-based polymer for plastic film production 33
2.6.4
Mechanical properties......................................... .......................................................... ...............................33 ..............33
2.7 Researches on Bioplastics Bioplastics ................................. .................................................. .................................. .........................34 ........34 2.7.1 Polyhydroxybutyrate Polyhydroxybutyrate and Hydroxyvalerate Hydroxyvalerate Production by Bacillus megaterium Strain A1 Isolated from Hydrocarbon-Contaminated Hydrocarbon-Contaminated Soil. .........34 2.7.2 Production and characterization characterization of PHB from a novel isolate Comamonas sp. from a dairy effluent sample and its application in cell culture 35 2.7.3 Production of PHB by a Bacillus a Bacillus megaterium megaterium strain using sugarcane molasses and corn steep liquor as sole carbon and nitrogen sources. .............35 2.7.4 Sustainable Embedding of the Bioplastic Poly-(3-Hydroxybutyrate) Poly-(3-Hydroxybutyrate) into the Sugarcane ........................... ............................................ .................................. .................................. ...............................36 ..............36 2.7.5 Polyhydroxybutyrate Polyhydroxybutyrate synthesis on biodiesel wastewater using mixed microbial consortia........................................... ............................................................ .................................. ...............................36 ..............36 Chapter 3:
Methodology ................................. .................................................. .................................. .................................. ...................37 ..37
3.1 Overall process ................................. .................................................. .................................. .................................. .........................37 ........37 3.2 Extraction of starch form Potato tubers ......................................... ......................................................37 .............37 3.2.1
Extraction process .................................. ................................................... .................................. .........................37 ........37
3.2.2
Selection of the potato .................................. ................................................... .................................. ...................38 ..38
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3.3 Preparation of the potato ........................................... ............................................................ ..................................38 .................38 3.3.1
Weighing ................................. .................................................. .................................. .................................. .........................38 ........38
3.3.2
Washing .................................. ................................................... .................................. .................................. .........................38 ........38
3.3.3
Weighing ................................. .................................................. .................................. .................................. .........................38 ........38
3.3.4
Peeling.................................. ................................................... .................................. .................................. ............................39 ...........39
3.3.5
Dicing ................................... .................................................... .................................. .................................. ............................39 ...........39
3.3.6
Blending and slurring.................................. ................................................... .................................. ......................39 .....39
3.3.7
Water Slurring.......................................... ........................................................... .................................. .........................40 ........40
3.3.8
Filtration.................................. ................................................... .................................. .................................. .........................40 ........40
3.3.9
Final starch ................................. .................................................. .................................. .................................. ......................42 .....42
3.4 Production of starch based bioplastic ................................. .................................................. .........................43 ........43 3.5 Biodegradable Biodegradable starch plastic process plant design ................................. ......................................45 .....45 3.5.1
Process consideration....................................... ........................................................ ..................................45 .................45
3.5.2
Extraction unit .................................. .................................................. .................................. ..................................45 ................45
3.5.3
Starch-based polymer production ................................ ................................................. ......................51 .....51
3.5.4
Starch-based biodegradable plastic film production .........................52 .........................52
3.6 Preliminary economic analysis over the starch-based plastic film process plant design ................................. .................................................. .................................. .................................. .................................. ......................54 .....54 3.6.1
Purchase Equipment Cost (PEC) ..................... ...................................... ..................................54 .................54
3.6.2
Total Direct Cost (TDC) and Total Indirect Cost (TIC) ....................55 ....................55
3.6.3
Fixed Capital Investment (FCI) ....................... ........................................ ..................................56 .................56
3.6.4
Total Capital Investment (TCI)................................. .................................................. .........................56 ........56
3.6.5
Total Product Cost (TPC) ............................. ............................................... .................................. ...................56 ...56
3.6.6
Profit or Loss................................. .................................................. .................................. .................................. ...................56 ..56
3.6.7
Payback ................................ ................................................. .................................. .................................. ............................57 ...........57
3.6.8
Internal Return of Rate (IRR) .................. ................................... .................................. .........................57 ........57
Chapter 4:
Results and Discussion .......................................... ........................................................... ............................57 ...........57
4.1 Chemistry behind the formation of starch based bioplastic ........................57 ........................57 4.2 Starch content of raw potato................................. .................................................. .................................. ......................58 .....58 iv
4.3 Number of starch-based biodegradable plastic carry bags..........................59 4.4 Economic analysis of the process plant.......................................................59 4.5 Mechanical testing of the bioplastic samples. .............................................60 Chapter 5:
Conclusion .........................................................................................63
5.1 Recommendations and Future works ..........................................................64 Chapter 6:
References ..........................................................................................65
Appendix: Economic analysis..................................................................................71 ANNEX 1 …………………………………………………………………………85 ANNEX 2…..……………………………………………………………………..87
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List of Tables Table No. Table 2.1
Table 2.2
Table 2.3
Table 2.4
Table 2.5 Table 4.1 Table A1 Table A2 Table A.3 Table A.4 Table A.5 Table A.6
Title Starch-based polymer comparison table Advantages of degradable plastics and starch-based plastics Disadvantages of degradable plastic and starch-based plastics Parameters of starch based plastic film production List of standard tests for plastic carry bags Economic analysis summation table Equipment cost and the industrial source Conversion table for purchased equipment Capacity and cost of equipment Total Direct Cost calculations Total Indirect Cost calculations Total Product Cost (TPC) calculations
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Page No. 28
29
30
33
34 60 72 74 76 77 78 79
List of Figures Figure No. Figure 2.1
Title Polyethylene Terephthalate
Page No.
Figure 2.2 Figure 2.3 Figure 2.4 Figure 2.5 Figure 2.6
High-Density Polyethylene PVC Low-Density Polyethylene Polypropylene Polystyrene Polycarbonate and Polylactide Plastic pellets Oxo-Biodegradable Plastic Master Batch / Additive Process of the bioplastic production Diced Potato Blending and Slurring Double layered cheesecloth for filtration Residue pulp of potato Starch after water extraction Dried starch Steps for producing bioplastic. Mass balance diagram over weighing unit Mass balance diagram over sampling and dry washing unit Mass balance diagram over reception area Mass balance diagram over rotating bar screen
21 21 22 22 22
Figure 2.7 Figure 2.8 Figure 2.9 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6 Figure 3.7 Figure 3.8 Figure 3.9 Figure 3.10 Figure 3.11 Figure 3.12
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20
23 23 24 38 39 40 41 41 42 42 44 45 46 46 47
Figure 3.13 Figure 3.14 Figure 3.15 Figure 3.16 Figure 3.17 Figure 3.18 Figure 3.19 Figure 3.20 Figure 3.21 Figure 3.22 Figure 3.23 Figure 4.1 Figure 4.2 Figure 4.3
Mass balance diagram over rotary washer unit Mass balance diagram over stone catcher unit Mass balance diagram over rotary screen peeler and buffer bin unit Mass balance diagram over rasper and mixer unit Continuous rotating vacuum filter Mass balance over the refining unit Mass balance diagram over hydrolysis tank Mass balance diagram over the polymer dryer and pelletizer unit Mass balance diagram over extrusion unit Mass balance diagram over the film and surface treatment unit Mass balance diagram over distribution unit Graph of force against Elongation for sample 1 Graph of stress against strain for sample 2 Graph of Stress against strain for sample 3
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47 48 49 49 50 52 52 52 53 53 54 61 61 62
Acknowledgement
First and foremost, I praise and thank God for the blessings, good health and wellbeing that were necessary to complete this project and thesis successfully. I would like to express my deep appreciation and sincere gratitude to the following people: -
My supervisor, Mr. A K Ragen for providing me the opportunity to work on this project and for his patience, encouragement, guidance and support over the last four years.
-
My friends and colleagues of the chemical engineering department who helped me in norms of difficult time.
-
My parents, Viraj Soomaree and Usha Khanna Luchmun, for raising me up in a good and healthy environment, which gave me a great starting point. I know I cannot thank them enough and there are no words that can truly express the level of gratitude and appreciation I have for them. I am very grateful from the bottom of my heart for everything they have done and sacrificed for me. "My Lord, have mercy upon them as they brought me up [when I was] small."
-
Everyone in the chemical engineering department of the University of Mauritius for funding, supporting and easing everything during my studies. Special thanks to Mr. D. Reedoye, Mr. Bheekun, Miss Pritima and Miss Parvati, the chemical laboratory technicians, for their valuable assistance, guidance and willingness to exchange information and ideas during the course of the experimental practical carried out in the laboratory.
Finally a graceful thanks to Dr. D Surroop, the head of the chemical department (year 2015/2016) for this assistance and helpful collaboration in the satisfaction of my needful requirements. ix
UNIVERSITY OF MAURITIUS
PROJECT/DISSERTATION DECLARATION FORM Name: Soomaree Keshav Student ID: 1114132 Programme of Studies: Chemical and Environmental Engineering Module Code/Name: CHE 4000Y (5) Title of Project/Dissertation: Production of Bioplastic Name of Supervisor(s): Mr. A.K. Ragen
Declaration: In accordance with the appropriate regulations, I hereby submit the above dissertation for examination and I declare that:
(i) I have read and understood the sections on Plagiarism and Fabrication and Falsification of Results found in the University’s “General Information to Students” Handbook (20…./20….) and certify that the dissertation embodies the results of my own work.
(ii) I have adhered to the ‘Harvard system of referencing’ or a system acceptable as per “The University of Mauritius Referencing Guide” for referencing, quotations and citations in my dissertation. Each contribution to, and quotation in my dissertation from the work of other people has been attributed, and has been cited and referenced.
(iii) I have not allowed and will not allow, anyone to copy my work with the intention of passing it off as his or her own work.
(iv) I am aware that I may have to forfeit the certificate/diploma/degree in the event that plagiarism has been detected after the award.
(v)
Notwithstanding the supervision provided to me by the University of Mauritius, I warrant that any alleged act(s) of plagiarism during my stay as registered student of the University of Mauritius is entirely my own responsibility and the University of Mauritius and/or its employees shall under no circumstances whatsoever be under any liability of any kind in respect of the aforesaid act(s) of plagiarism.
Signature:
Date:
x
Abstract
The aim of the project was to study the potential of producing starch-based bioplastics using potato as feedstock in Mauritius. The methodology of the project started with the preparation of the potato which included weighing, washing, peeling, dicing. It was followed by blending, slurring and filtration so as to extract maximum starch. The second step was the production of the bioplastic where acid and chemicals was added to the starch with the presence of heat. Some mechanical and physical tests were done on some bioplastic samples and it was found that the bioplastic could withstand a load of 1 Kg with an elongation of 105 mm at break and 62 mm at peak, strain of 76% at break and 46% at peak, a stress of 0.063 N/mm2 at break and 0.207 N/mm2 and finally a young’s modulus of 3.467 N/mm 2. From the investigation, 25% of starch was extracted from local potatoes with a bulk density of 1450 kg/m3. The processing capacity of 10 tons per day of potato is promising and would supply a starch-based plastic process plant with 3.17 tons per day of starch which would subsequently be used to produce approximately 10.686 tons of starch based plastic film. However, it was observed that the supply of potato should increase so that the starch-based plastic plant can be supplied with approximately 3330 tons of tuber per year. Besides, the feasibility of the proposed process plant for the production of the starch-based plastic carry bags was viable with a payback period of 4.20 years for a total production of approximately 117 million of starch based plastic carry bags per year being sold at the proposed price of Rs 1.55. It was thus concluded that bioplastics from potato starch was a feasible solution as a substitute for petroleum based plastics.
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List of Abbreviations Abbreviations μ
Meaning Microns
ASTM
American Society for the Testing of Materials Celsius
O
C
CO2 CTCRI
Carbon Dioxide Central Tuber Crops Research Institute
EPI FAO
Environmental Crops Inc Food and Agriculture Institute
FCI g
Fixed Capital Investment Grams
GDP HDI
Gross Domestic Product Human Development Index
HDPE HMF
High Density Polyethylene Hydroxymethylfurfural
IRR Kg
Internal Rate of return Kilogram
LDPE m
Low Density Polyethylene Mass flow rate
m3 ml
Cubic metre millilitres
MSW NA2S2O5
Municipal Solid Waste Sodium Metabisulphite
PBS PCL
Polybutylene Succinate Polycaprolactone xii
PE PEC
Polyethylene Purchase Equipment Cost
PET PFD
Polyethylene Terephthalate Process Flow Diagram
PHAS PHB
Polyhydroxyalkanoates Poly-3-Hydroxybutyrate
PHH PHV
Polyhydroxyhexanoate Polyhydroxyvalerate
PLA PP
Polylactic Acid Polypropylene
PS PSM
Polystyrene Plastarch Materials
PVC rpm
Polyvinyl Chloride Revolutions per minute
SPI TCI
Society of the Plastic Industry Total Capital Investment
TDC TIC
Total Direct Cost Total Indirect Cost
TPC UN
Total Product Cost United Nations
v
Volumetric Flow Rate
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Chapter 1:
Introduction
1.1 Background Mauritius, a volcanic island nation in the Indian Ocean, is situated near Reunion Island to the East of Madagascar. The island has an assessed population of about 1.3 million which covers an area of about 2,000 square kilometres with a population density of 635 people per each square kilometre (World Bank, 2014). According to the Statistic Mauritius (2015), the GDP per capita of the island was recorded to 6679.21 US dollars in 2013 while the inflation rate was 0.2 % reported for the month of December 2014. Due to an increase in the population, the amount of waste generation is constantly on the increase year by year. This eventually affects the waste handling and management locally since, the island possesses only one dumping ground which is itself undersized. Indeed, the landfill was initially designed for 400 tons per day where now more than 1,200 tons per day of waste is being inputted to the present day (Indian Ocean Times, 2015).
1.2 An overview on plastics Basically, plastics can be classified as a group of man-made or natural organic materials that can be molded and then hardened, including many types of resins, resinoids, polymers, cellulose derivatives, casein materials, and proteins Plastics, made from non-renewable resources such as petroleum products, are now very common and are being used almost everywhere as such; in packing materials, in bottles, cell phones, plastic bags and more. They are being so extensively used because of their durability, strength, malleability, low reactivity and cost efficiency. However, together with all its benefits is the fact that it is highly pollutant and plastics nowadays have become a big environmental issue. Nowadays, people are more aware about the harmful effects of petrochemical derived plastic materials in the environment. Researchers have conducted many researches for
managing plastic waste on earth by finding eco-friendly alternative to plastics. This ecofriendly alternative is bioplastics, which are disposed in environment and can easily degrade through the enzymatic actions of microorganisms. The degradation of biodegradable plastics give rise to carbon dioxide, methane, water, biomass, humic matter and various other natural substances which can be readily eliminated (Azios, 2007). Plastic bags has be banned in Mauritius from the 1 st January 2016 as Environment Protection (Banning of Plastic Bags) Regulations 2015 have been amended to avoid all confusion around the definitions of plastic and plastic bags. The regulations prohibit import, manufacture, sale, or supply of a plastic bag as from 1 st January 2016. The regulations concern only the vest-type plastic bags, roll-on bags and Non-Woven Polypropylene bags, which are designed to carry goods purchased at points of sale such as wholesale and retail outlets, markets, fairs and hawkers. The import, manufacture, sale or supply of biodegradable and compostable plastic bags is allowed subject to strict conformity to appropriate standards specified in the regulations.
There is thus a need for a more sustainable alternative such as bioplastics and this study accounted for the production of bioplastic from potato starch so as to assess its feasibility.
1.3 Plastics in Mauritius Plastic carry bags are the most widely used form of plastic in Mauritius and the disposal of the bags are alarmingly increasing each year. It is estimated that over 360 million plastic bags are brought in the local market and around 1 million are disposed of at the only landfill. (MOE; L’Express, 2006). For the time being, Mauritius is facing a real problem concerning the disposal of solid waste. Indeed, Mare Chicose, the only landfill of the island has a daily generation of about 1,200 tons of Municipal Solid Waste (MSW) while it was designed for 400 tons per day (SWM Division, 2012). It is clearly noted that the dumping ground is undersized.
Also, MSW constitutes the highest proportion of wastes in the order of 70% that are disposed of at the landfill ( CODWAP, 2009 ). It can be classified into yard wastes, food wastes, plastics, paper, textile, metals, glass and others. About 80% of the wastes are organic (paper, food and yard wastes). The amount of yard waste composition is about 43% and that of food waste around 25%. The inorganic wastes that make up about 20 % of the waste stream consist of plastics, glass, metal, textile and others. The main component of the non- organic waste is plastics, making up on average about 13 % by volume, representing around 37,000 tons of the MSW generated annually (NRFE, 2011). With its slow degradation rate, plastics represent one of the major potential threat to the environment.
1.4 Production of plastics The production of plastic around the world represents over 90 million tonnes and the growth is assessed to be around 3% per year. The worldwide production of plastic has grown by more than five hundred percent during the last 30 years (Plastinum Polymer Technologies Corp, 2009). Around 6% of the world oil supply is used in the production of plastics and it is mainly used for the plastic packaging and vehicle assembly and in construction (Zawya, 2011). For example in the north of America and the western European countries, the amount of plastic consumed is about 100kg per capita and is estimated to reach 140kg per capita by 2015.
1.5 Plastic Carry Bags As per the Environmental Protection Act 2004 governing ‘Plastic Carry Bags’ the plastic carry bag is defined as ‘the vest-type carrier bag made of plastic designed for the general purpose of carrying goods purchased by consumers’ (Ministry of Environment and Sustainable Development, 2004). Most of today’s plastics come from petrochemicals and are not biodegradable. In addition to that, there are depleting reserves of those petroleum resources. Also, incineration of plastics as such is not an appropriate method as there are high toxin emissions such as dioxins and furan, adding to environmental issues. Though
plastic recycling has some advantages, it is considered to have a negative impact on our ecosystem as an important amount of energy is required during the recycling phase. Since then, there have been major interests to replace conventional plastics by degradable ones. Results indicated that plastics from renewable sources would degrade in a time frame of 60 days, while those with biodegradable additives would require more time (Mohee et al., 2006). Hence, for the different reasons mentioned, it is clear that biodegradable polymers would add ample to sustainable development.
1.6 Objectives of the project Biodegradable plastics present a potential alternative to petroleum-based plastics. Reducing oil consumption and promoting a greener environment remain an important goal for the sustainably-minded today. This study aim is to investigate the potential of producing bioplastics from potato starch in Mauritius. The main objectives of this study are:
To carry out a literature review on plastics and bioplastics in Mauritius and abroad.
To investigate the feasibility of local potato as main feedstock.
To perform tensile stress, strain, elasticity and young’s modulus test on some bioplastic samples produced.
To perform an economic analysis of a designed plant of potato starch based bioplastic and to check for its economic feasibility.
1.7 Structure of the report The report has the following structure: Chapter 1 introduces the plastics waste issues in Mauritius and an overview of
plastics production worldwide. Chapter 2 covers a profound review on plastics taking into consideration the
biodegradability concept. A review of relevant studies on biodegradable plastics is discussed.
Chapter 3 describes the way used to extract the starch from the potato and the
different materials and methods adopted produce the biodegradable starch polymer from the potato starch extracted.
Chapter 4 encloses the results and discussions part. A summary of the results is
tabulated.
Chapter 5 gives an overall conclusion of the results obtained from the study. The
possible recommendations and future works are also illustrated.
The appendices contains an economic analysis and other appropriate sheet and
relevant information are also annexed.
Chapter 2:
Literature Review
The literature review contains the basic information about plastics and the importance behind the production of the biodegradable plastics as an alternative to degradable plastic. The different aspects behind the process undergone for production of the raw material are studied in this chapter.
2.1 Types of plastics Different types of plastics exist, depending on the raw material used. They are as follows: 1. Petroleum plastic Petroleum plastics are plastic that originate from petroleum monomers that are chemically processed to produce polymers. They do not degrade as easily as bioplastic. 2. Degradable plastic Degradable plastics are plastic that have been manufactured along with a particular blend of biodegradable additives in order to alter the chemical characteristics of the product when exposed to specific environmental conditions (Doty, 2005). 3. Biodegradable plastic From the ASTM D6400 definition, a biodegradable plastic is a plastic that can be degraded by the action of naturally occurring microorganisms such as bacteria, fungi and algae or by the action of sunlight and water (Doty, 2005). 4. Bioplastic Bioplastic is a type of plastic that is derived from natural raw materials such as biomass and corn starch. This type of plastic will degrade when exposed to environmental conditions such as moisture, naturally occurring microorganisms such as bacteria, fungi and algae or in a composting condition. 5. Oxo-biodegradable plastic Oxo-biodegradable plastic is a type of plastic made with a small amount of metal salt added to the polymer. When disposed of, the plastic comes into contact with oxygen and starts to degrade. The resulting by-product of the Oxo-biodegradable plastic is carbon
dioxide, water and biomass. The Oxo-biodegradable plastic additives usually used include the EPI additive, used in Tesco plastic bags and Clariant. (Tan,2011) 6. Compostable plastic Compostable plastic, as defined by the ASTM D6400, is a plastic which will undergo biological degradation to yield carbon dioxide, water, biomass and inorganic material when subjected to a biological environment such as in a compost bin. There will be no harmful material left at the end of its product life (Tan,2011). 7. Photodegradable plastic Photodegradable plastic is a type of plastic that decomposes on exposure to sunlight. This is because they become brittle and break down into small pieces thus reducing the amount and volume of waste and environmental deterioration.
2.2 Degradable plastics Degradable plastic is the most common type of plastic used and is produced from the raw materials including crude oil and natural gas. 2.2.1 Plastics Codes There exists different type of plastic used for various material production. They have diverse characteristics and each of them have their respective properties. Below is the different types of codes used for the degradable plastics that are manufactured according to the Society of the Plastics Industry (SPI). I.
The first one includes Polyethylene Terephthalate also known as PET. Items made from this plastic are commonly recycled.
Figure 2.1: Polyethylene Terephthalate (Plastic recycling, 2014)
II.
High-Density Polyethylene (HDPE). HDPE products are very safe and they are not known to transmit any chemicals into foods or drinks. HDPE products are commonly recycled.
Figure 2.2: High-Density Polyethylene (Plastic recycling, 2014) III.
Made with Polyvinyl Chloride (PVC). PVC is not often recycled and it can be harmful if ingested.
Figure 2.3: PVC (Plastic recycling, 2014)
IV.
Plastic marked with an SPI code of 4 is made with Low-Density Polyethylene, or LDPE. LDPE is not commonly recycled but it is recyclable in certain areas.
Figure 2.4: Low-Density Polyethylene (Plastic recycling, 2014) V.
Plastic marked with an SPI code of 5 is made with Polypropylene, or PP. PP is not commonly recycled, but it is accepted in many areas. This type of plastic is strong and can usually withstand higher temperatures.
Figure 2.5: Polypropylene (Plastic recycling, 2014) VI.
Plastic marked with an SPI code of 6 is made with Polystyrene (PS) and commonly known as Styrofoam. It is commonly recycled.
Figure 2.6: Polystyrene (Plastic recycling, 2014)
VII.
Designates miscellaneous types of plastic not defined by the other six codes. Polycarbonate and Polylactide are included in this category. These types of plastics are difficult to recycle.
Figure 2.7: Polycarbonate and Polylactide (Plastic recycling, 2014) 2.2.2 Production of degradable plastics The preliminary process for producing degradable plastic consist of the cracking process. This involves converting the oil obtained from petroleum resources into monomers of hydrocarbons such as ethylene and propylene. The monomers are then formed into polymers, followed by plastic pellets production. Plastic pellets, as shown by the Figure 2.1, are required for plastic production.
Figure 2.8: Plastic pellets (Plastic recycling, 2014) The principle behind the production of degradable plastic includes melting the plastic pellets along with the biodegradable plastic pellets at a temperature between 200oc to
275oc depending on the polymer. The melted polymer is then forced through either a die or into a mould to produce the desired plastic product before being cooled. There are four types of process used for production of the different types of plastic are: 1. Extrusion of plastic 2. Injection molding or blow molding 3. Plastic blow extrusion 4. Rotational molding
2.2.3 Biodegradable plastic additives Figure 2.2 shows additives, which are basically chemicals added to degradable plastics during their production to render them degradable when exposed to different environmental conditions or sunlight. These additives though referred to as biodegradable plastic additives only cause the plastic product to be degraded and as a result still cause the problem of plastic disposal. Some other types of additives are added to enhance the properties of the plastic product such as protection against UV light or for coloring.
Figure 2.9: Oxo-Biodegradable Plastic Master Batch / Additive (Plastic particle water pollution, 2016)
2.3 Biodegradable plastics Biodegradable plastics are plastics produced from natural materials that are mostly organic materials such as corn, pea starch, cellulose based materials and potato.
Biodegradable are considered as substitutes to degradable plastics since they have many characteristics that favors them concerning their environmental benefits. Figure 2.10 shows the life cycle of a biodegradable plastic.
Figure 2.10: life cycle of a biodegradable plastic (Instructable, 2010) 2.3.1 Classification of biodegradable plastics Biodegradable plastics can be classified as follows: f ollows: 1. Cellulose based plastics Cellulose based plastic are plastics produced from cellulose resources such as wood and other plant materials. The mechanism behind producing cellulose based bioplastic involved the conversion of the the glucose glucose found in the cellulose cellulose from the plant or biomass into hydroxymethylfurfural (HMF). However this technology is quite expensive and still requires a lot of research before commercial applications. 2. Aliphatic polyesters This type of polymer has similar characteristics as Polyethylene (PE) and Polypropylene (PP). They are used for the production of beverage bottles or trash bags. This type of polymer can be manufactured by conventional plastic plastic process and
are resistant to high temperatures up to 260oC. However this type of polymer is also resistant to microbial degradation. (Lenau, 2003). 3. Polylactic acid (PLA) plastic PLA is derived from natural resources such as corn or sugar sug ar cane (glucose). It can be processed easily on conventional petroleum plastic machinery and has many similar s imilar characteristics. PLA usually comes in granular forms and can be used along processing lines to manufacture foils, cups cups and bottles. bottles. 4. Poly-3-hydroxybutyrate (PHB) Poly-3-hydroxybutyrate (PHB), a biopolymer, is a polyester produced by some microorganisms that feed on starch or a source of glucose. PHB shows interesting characteristics as an alternative to degradable plastics because it is a transparent film at a melting point higher than 130 oC and is completely biodegradable. biodegradable . 5. Polyethylene derived from biomaterials Polyethylene can be derived from biomaterials such as the fermentation of corn or sugarcane. It is a polymer of ethylene which can be produced from ethanol. The polyethylene obtained from the organic raw materials is similar to the petroleum derived polyethylene. However the polyethylene does not biodegrade but can be recycled. recycled. 6. Starch based plastics Starch based plastics are plastic produced from starch which possesses the ability to observe plastic properties similar to thermoplastic polymers. Around 50% of the market of bioplastic is starch-based plastic or bioplastic. It is currently the most important and extensively used bioplastic used.
2.4 Starch based plastic In this project, the production of a starch-based polymer for the production of starch based plastic films was investigated. Starch-based plastic is an interesting alternative to degradable plastics since they present multiple advantages. They are produced from natural resources and do not affect the environment after degradation. In Europe, most
of the plastic used nowadays are starch-based. It can either be recycled or reused as well as composted thus offering environmental benefits over degradable plastics. When the starch based plastic is composted, the compost is returned back to the raw material and when it is reused or recycled, the manufacturer recycles the bioplastic for future use. 2.4.1 Starch Starch is a naturally occurring soluble carbohydrate that can be obtained from various raw materials such as corn, potato, cassava, rice and sweet potato. Starch is produced by plants mainly as an energy reserve. 2.4.2 Characteristics of starch Starch exhibits some similar properties as polymers when subjected to h ydrolysis. There exists two type of molecules in starch namely unbranched molecules which consist of glucose and branched molecules which consist of amylose and amylopectin. The shapes as well as the size of the granules of the starch are important factors to be considered during processing concerning their properties (Mweta, 2009). 2.4.3 Different types of starch sources Starch can be obtained from different plant sources. Sweet potato, potato, cassava and maize are some sources of starch locally available in Mauritius. Starch sources from potato, sweet s weet potato, p otato, cassava and maize were investigated and the different aspects of the polymers were examined. A comparison table was drawn for the different sources o f starch to identify the best raw material for the study. Table 2.1 shows the results obtained as comparison.
Table 2.1: Starch-based polymer comparison table
Properties
Potato
Type of source
Tuber
Tuber
Tuber
Grain
Availability in Mauritius Mauritius
High
Average
Average
Low
Harvest time1 (months)
3
6
8-9
3
6-8
8.5 - 10.5
56250
Harvest
quantity2 (tons/ 10.5 – 10.5 – 14.5 14.5
Swe Sweet potato
Cassava
acre)
Ma M ai ze
units
Production in 20133 (in 882
435
435
53
tons)
P olyme lymer spe specif ci fi cati catio ons Starch extracted
Good
Good
Good
Good
Ease of working
Good
Good
Average
Good
Texture
Good
Good
Sticky Too liquid
Drying feature
Good
Good
Low
Very low
Strength
High
High
Low
Low
1
AREU, 2004, 2AREU, 2004, 3Central statistical Office, 2013
From Table 2.1, the most advantageous raw materials were potato and sweet potato. The other sources of starch did not show possible industrial exploitation to produce starch based polymer and consequently starch-based biodegradable plastic films in Mauritius. The island has almost reached an auto-sufficient supply in potato whereas sweet potato harvest represents a greater supply than the demand thus resulting in an excess of the tuber on the market. However, when using potato as the raw material source of starch in the process consideration, a situation of food crisis may arise in the th e island. 2.4.4 Properties exhibited by starch during polymer synthesis Starch can be processed to produce natural polymers. Starch polymer has the ability to sustain water and thus water can be used in the production of the starch-based polymer. However the final properties of starch polymer depend mostly on the type of raw material. For example tubers such as potato and cassava starch have low protein content
but high phosphate content as compared to wheat starch and according to a recent study (Mweta, 2009). This gives tuber a better biodegradability as compared to wheat starch.
2.5 Comparison study Degradable plastic and biodegradable plastic derived from starch are two types of plastics that can be used for the production of plastic carry bags. However they both have their qualities and weaknesses as illustrated in Tables 2.2 and 2.3. 2.5.1 Advantages of degradable plastics and starch-based plastics TABLE 2.2: ADVANTAGES OF DEGRADABLE PLASTICS AND STARCH -BASED PLASTICS
Degradable plastics
Starch-based plastics
They are light weighed and malleable They do not cause the death of marine and can be used for the production of animals such as the tortoise in the sea. plastic carry bags. They have strong mechanical and They do not affect the environment in physical properties in contrast to starch the based plastics.
form
of
water
pollution
or
environmental pollution.
They are light weighed and show strong As opposed to degradable plastics, mechanical properties.
biodegradable
plastics
require
less
energy to be produced. They are resistant to chemicals and can They are light weighed and malleable be used for production of storage and can be used for the production of containers for chemical products.
plastic carry bags.
They can be used as insulators in many They reduce the dependency on fossil appliances.
fuels for the production.
They are malleable and can be molded They are made from renewable raw into a variety of complex forms.
materials such as corn starch and biomass.
2.5.2 Disadvantages of degradable plastics and starch-based plastics TABLE 2.3: DISADVANTAGES OF DEGRADABLE PLASTIC AND STARCH -BASED PLASTICS
Degradable plastics
Starch-based plastics
They are made from nonrenewable raw They show weaker mechanical and materials such as crude oil thus making chemical properties as compared to this type of plastic not environmentally degradable plastics. sustainable. They generate a lot of solid waste They do not have a long life time since though some degradable plastics can be they recycled.
degrade
environmental
in
the
presence
conditions
such
of as
microorganisms and moisture. Degradable plastics are sometimes not Has a considerable cost thus affecting biodegraded thus contributing to the its economic sustainability. increasing amount of solid waste in landfills where they remain unchanged and
unaffected
by
environmental
conditions. They cause the death of marine animals such as the tortoise in the sea. According to Liam Bartlett (2008), more than 100,000 marine animals are killed each year due to plastic pollution in the sea ( Bartlett et al., 2008). When degradable plastic are burnt, they release harmful emissions such as dioxins that causes health problems.
Degradable plastic production is very energy intensive processes requiring a large amount of energy. Not environmentally sustainable. Some
types
of
plastic,
such
as
polycarbonate (Bisphenol A, BPA), are believed to cause health problems such as on the nervous system especially regarding infants.
The qualities of biodegradable plastic made from starch raw material outweigh the qualities of degradable plastics and thus biodegradable starch plastic can b ecome a strong alternative to degradable plastic.
2.6 Starch based polymer and plastic plant design The design of the starch based biodegradable plastic plant includes three main steps namely: 1. The extraction of starch from sweet potato 2. The starch-based polymer production 3. The processing of the polymer for starch-based biodegradable plastic film production 2.6.1 Extraction of starch from potato For the extraction of starch from potato, there are three main procedures that exist that is; alkali extraction medium, water extraction medium and enzymatic extraction medium. 1. Alkali extraction medium
Alkali medium extraction of starch from tuber consists of using an ammonia solution (0.03M) by normal settling method. This type of extraction was done with three
different types of tuber crops namely from Colocasia, Dioscorea esculenta starches and potato (Moorthy, 1990).
2. Water extraction medium
Water extraction is the most popular extraction means of extracting starch from tubers. In this procedure of isolation, the potato is washed, peeled and diced to increase the surface area exposed to the following blending and slurring purposes. The diced potato is then blended and scurried directly in a solution of water and crushed ice in the ratio of 1: >10 (w/w) to expose the starch granules from the potato. Tubers are rich in sugar and protein and when exposed to air, they form colored components. A Sulphur component is usually added to the mixture to prevent any oxidation. The milk starch is then refined and dried to obtain the required starch (Vasanthan, 2001). 3. Enzymatic extraction medium
Enzymatic extraction is also another process that can be used for the extraction of starch from raw materials such as potato and cassava. Starch extraction by water and acid extraction can cause loss of starch up to 20%. Enzyme extraction of starch includes treating the ground starch-rich raw material with Pectinolytic and Cellulase enzymes (J.Kallabinski et al., 1991). The process involves incubation of the cultured starch material at a temperature of 45 oC. 2.6.2 The biodegradable polymer production from the starch Starch can be processed to produce a starch-based polymer. The starch is first hydrated with water and then hydrolyzed with a weak acid such as acetic acid or 0.1M HCL. Evaporation of water from the starch solution causes the amylose chain alignment and increases attraction between the polymeric chains through hydrogen bonding (Rechial et al., 2010). However the polymer does not exhibit plastic properties at this stage (Instructable, 2010). Sorbitol and glycerin are two types of plasticizer added to the starch to enhance its plasticity. Heat (between 90 oC to 180oC) (Vilpoux et al., 2003) is provided to promote the swelling and hydrolysis process of the starch.
2.6.3 The processing of starch-based polymer for plastic film production The starch-based plastic polymer can be further processed along with other biodegradable components such as the Polylactic acids (PLA) or Polycaprolactone (PCL) (Michigan Technological University, 2005) in a conventional plastic extruder machine to produce the desired plastic product. The extrusion technology is used since a long time mainly for the corn starch processing such as for packaging materials production (Peng et al., 2003 ). According to a study (Bhatnagar et al., 1996) biodegradable plastic does not show good storage characteristics when exposed to moisture. The addition of additives such as magnesium silicate or polycarbonate can reinforce the properties of the starch products (Bhatnagar et al., 1996). There are some parameters such as the temperature or blending ratio that need to be respected during the processing of the biodegradable plastic. According to a study, (Bhatnagar et al., 1996) the ratio of starch polymer to the additive can be 70:30 on a dry basis. Also this study shows that the properties of the final product will depend on the type of starch used for the production of the plastic product. Some parameters for the production of starch-based polymers or ‘thermoplastic starch’ (TPS) from pea starch by using a twin screw extruder are illustrated in Table 2.4. TABLE 2.4: PARAMETERS OF STARCH -BASED PLASTIC FILM PRODUCTION
Feature
Parameters
Starch rate of flow (kg/hr)
12
Plasticising rate of flow (L/h)
3.6 - 4.8
Screw rotation speed (rpm)
110 -160
Temperature of plasticization zone (oC) 110 – 120 Product temperature when leaving the 55 - 60 extruder (oC) Die pressure when product leaves the 50 – 60 extruder (bar) Specific Mechanical Energy (kJ/kg)
1050 - 1400
(Source: Vilpoux et al., 2003) 2.6.4 Mechanical properties The mechanical properties of degradable plastic can be tested according to the Environment al Protection Act 2004 governing ‘Plastic Carry Bags’ , made by the
Minister under section 96 of the environment Protection Act 2004 (Ministry of Environment and Sustainable Development, 2004), plastic carry bags are tested according to different standards of the American Society for Testing and Materials (ASTM). The different standards are listed in Table 2.8. TABLE 2.5: LIST OF STANDARD TESTS FOR PLASTIC CARRY BAGS
Feature Degradation tests
ASTM test ASTM D3826 – 98: standard practice for determining endpoint in degradable polyethylene and polypropylene using a tensile test ASTM D 5208-01 - Standard practice for operating fluorescent ultraviolet (UV) and condensation apparatus for exposure of photodegradable plastics ASTM D 5510-94 - Standard practice for heat ageing of oxidatively degradable plastics Thickness test TM D 374 - Standard Test Method for Thickness of Solid Electrical Insulation (Ministry of Environment and Sustainable Development, 2004)
2.7 Researches on Bioplastics 2.7.1 Polyhydroxybutyrate and Hydroxyvalerate Production by Bacillus megaterium Strain A1 Isolated from Hydrocarbon-Contaminated Soil. As per, Demirbilek et al., an alternative microbial resource as a bioplastic producer were found. From all the isolates, the Al strain produced 44% poly (b- hydroxybutyrate) (PHB) with reference to its dry cell weight. The molecular identification of the 16S RNA gene showed that this bacterium was a strain of Bacillus megaterium. The optimization studies led to the conclusion that the highest poly (b-hydroxybutyrate-cohydroxyvalerate) (PHBV) production was 78% when 5% molasses was used as the carbon source at pH 6 and 35_C after 60 h of incubation. Differential scanning calorimetry was used to determine the thermal properties of the PHB and PHBV that
were synthesized with sucrose and molasses as carbon sources, respectively. The molecular weights of PHB and PHBV synthesized with sucrose and molasses were calculated as 428 and 498 kDa, respectively, according to the viscometric method. The study indicated that the B. megaterium strain A1 is an alternative microbial resource as a bioplastic producer. (Demirbilek et al., 2014) 2.7.2 Production and characterization of PHB from a novel isolate Comamonas sp. from a dairy effluent sample and its application in cell culture From the research carried out by Raveendran et al., optimizing various process parameters affecting fermentation for PHB production by Comamonas sp. Were carried out. The optimum conditions for PHB production were yeast extract concentration of 1%, pH 6.0 and inoculum concentration of 5.5%. Under optimized conditions the PHB yield was 0.523 g/g. The extracted polymer was characterized by FTIR and 1H NMR. Nanomatrices and solid walled matrices were prepared using the extracted PHB. Cytotoxic studies revealed that both solid walled and nanomatrices prepared from the extracted PHB showed almost 100% survivals of H9c2 cells. (Raveendran et al., 2015). 2.7.3 Production of PHB by a Bacillus megaterium strain using sugarcane molasses and corn steep liquor as sole carbon and nitrogen sources. K. Gouda et al., worked on the production of PHB by Bacillus Megaterium using molasses and corn steep as nutrient sources. It was found that Poly (hydroxybutyric acid) (PHB) and other biodegradable polyesters are promising candidates for the development of environment-friendly, totally biodegradable plastics. The use of cane molasses and corn steep liquor were found to reduce the cost of producing such biopolyesters. Result shown that maximum production of PHB was obtained with cane molasses and glucose as sole carbon sources (40.8, 39.9 per mg cell dry matter, respectively). The best growth was obtained with 3% molasses, while maximum yield of PHB (46.2% per mg cell dry matter) was obtained with 2% molasses. Corn steep liquor was the best nitrogen source for PHB synthesis (32.7 mg per cell dry matter), on the other hand, best growth was observed when ammonium chloride, ammonium sulphate, ammonium oxalate or ammonium phosphate were used as nitrogen sources. (K. Gouda et al., 2001).
2.7.4 Sustainable Embedding of the Bioplastic Poly-(3-Hydroxybutyrate) into the Sugarcane From the research of Martin Koller et al., biodegradable polymer poly-(3hydroxybutyrate) (PHB) were made economically competitive with common end-of pipe plastic materials from petrochemistry, the production costs have to be reduced considerably. The embedding of the industrial PHB production into a sugar and ethanol factory starting from the raw material sugarcane made it possible to achieve a production price per kilogram PHB that is 4 – 5 times lower than known for prior PHB production processes. The availability of the substrate sucrose in high quantities leads to the gained price advantage. Together with the application of ethanol as an alternative fuel, CO2 emissions from the production plant return to the sugarcane fields via photosynthetic fixation, resulting in a carbon balance of nearly zero. The utilization of medium chain length alcohols, by-products of the ethanol production integrated in this plant, substitutes the classic PHB extraction method using chlorinated agents. (Martin Koller et al., 2009). 2.7.5 Polyhydroxybutyrate synthesis on biodiesel wastewater using mixed microbial consortia R. Coats et al., worked on the synthesis of PHB using mixed microbial consortia and biodiesel wastewater as main source of nutrient. In the study they investigated PHA production on CG using mixed microbial consortia (MMC) and determined that the enriched MMC produced exclusively polyhydroxybutyrate (PHB) utilizing the methanol fraction. PHB synthesis appeared to be stimulated by a macronutrient deficiency. Intracellular concentrations remained relatively constant over an operational cycle, with microbial growth occurring concurrent with polymer synthesis. PHB average molecular weights ranged from 200 – 380 kDa, while thermal properties compared well with commercial PHB. The resulting PHB material properties and characteristics would be suitable for many commercial uses. (R. Coats et al., 2010).
Chapter 3:
Methodology
3.1 Overall process The figure 3.1 shows the process of the bioplastic production.
Figure 3.1: Process of the bioplastic production
3.2 Extraction of starch form Potato tubers 3.2.1 Extraction process
Water medium was chosen for the extraction because it was observed that the extraction rate was enhanced as compared to alkali extraction. With alkali medium, the extraction of starch from potato is decreased as compared to other tubers such as the family of Colocasia which includes the cocoyam (Moorthy, 1990).
3.2.2 Selection of the potato
The potato selected for the extraction was bought at the local vegetable market of ‘ Mahebourg ’ in the island. The potato is grown in Mauritius thus showing all the characteristics required for the project.
3.3 Preparation of the potato There were a few procedures followed before the extraction of the starch from the sweet potato. These included the: 1. Weighing 2. Washing 3. Peeling 4. Dicing 3.3.1 Weighing The selected sweet potato was first weighed. This was done to obtain an initial mass of the tuber. Potato tubers with a total weight of approximately one kilogram were used in the extraction. The ratio of the impurities to the potato was then determined by the difference in the weighing before and after washing. 3.3.2 Washing The selected potato was then washed with water to remove the contaminants such as dirt, soil, small roots and other unwanted plant materials which could otherwise affect the final output of the tuber. The rubbing in the washing step is an important quality factor since this step will determine the purity factor of the potato. There are many impurities that are similar to the final starch. To avoid any contamination in the final product, proper washing was done (International Starch Institute, 2006). 3.3.3 Weighing The washed potato was again weighed to obtain the difference in the weighing before and after washing.
3.3.4 Peeling The washed potato was then hand peeled using a knife. Care was taken to avoid unnecessary peeling of the potato cells. This would otherwise cause loss of the pulp and starch granule from the potato resulting in starch loss. A large amount of damaged starch granule could lead to alteration in the physiochemical properties of the starch to be extracted according to the procedure chosen. The peels obtained from the potato can be sent to an organic compost company for further processing that can be consequently used as an organic fertilizer in the potato agricultural lands instead of chemical fertilizers. This would reduce the plantation cost of the farmers. 3.3.5 Dicing The peeled potato was then carefully hand diced to small regular cubes of similar size (as far as possible the dimensions of all the cubes were respected). Care was taken to avoid damage of the starch granule in the sweet potato. Figure 3.1 shows the dices potato tubers.
Figure 3.2: Diced Potato 3.3.6 Blending and slurring The blending and slurring procedure of the potato sample was done in water by using a blender. This type of slurring is done for the potato because the tissues of the tuber are
soft and require no grinding as compared to hard plant tissues such as for cereal or legume grains according to the protocol adopted (Thava Vasanthan, 2001).
Figure 3.3: Blending and Slurring 3.3.7 Water Slurring For water slurring of the sample of diced potato, the ratio of the tuber to water added was 1 : >10 (w/w). For the sample of 890g of diced sweet potato, a total mass of 9790g (0.00979m3) of water was added, that is eleven times more water by weight. During the water slurring, crushed ice was added to the mixture to avoid heat-induced damage to the starch granule (Thava Vasanthan, 2001). However the total weight of water added was carefully controlled. 3.3.8 Filtration The filtration procedure was done by passing the slurry obtained through double -layered cheesecloth. The filtration procedure was done to separate the starch granules extract from the residue of the potato as shown in Figure 3.3 (left). The starch was washed into the filtrate by spraying water from a wash bottle onto the residue. The lack of opa city of the filtrate, Figure 3.3 (right), indicates appropriate washing. Squeezing of the cheesecloth was avoided. The residue of the potato, Figure 3.4, was blended two more times and filtered again to maximize recovery of the starch from the potato.
Figure 3.4: Double layered cheesecloth for filtration
Figure 3.5: Residue pulp of potato
3.3.9 Final starch The figure 3.6 shows the final starch obtained after extraction while figure 3.6 shows the starch after drying.
Figure 3.6: Starch after water extraction
Figure 3.7: Dried starch
3.4 Production of starch based bioplastic The methodology of producing the bioplastics is as follows:
15g of dried potato starch was diluted with 150ml distilled water in a 500ml beaker.
The beaker was brought on a heater plate including a magnetic stirrer.
A magnet stick was added in the beaker and let stirring at 2 r.p.m.
18ml of 0.1M HCl was pipetted in the mixture and the same amount of 0.1M NaOH was added for neutralization.
12ml of 1% glycerol was added.
The heater was switched to 100oC.
The mixture was allowed to heat for about 15 mins and the stirrer was brought to 3 r.p.m as the mixture was hardening.
The mixture took about 1 hour to form an opaque gel.
The gel was spread on a mold of 2 mm thickness.
The sample was allowed to dry.
The figures below show the steps used for the preparation of the bioplastics
Figure 3.8: steps of producing bioplastic.
3.5 Biodegradable starch plastic process plant design 3.5.1 Process consideration The process flow chosen for the extraction of the starch was the Potato Starch Production from the International Starch Institute, 2006. The process consideration of the starch-based plastic film process plant was considered in this unit. The process plant for a total capacity of 10 tons per day of potato was considered. 3.5.2 Extraction unit The first unit of the process plant consisted of the extraction unit. The extraction unit is the unit where the starch will be extracted from the potato. The different sub units of the first unit are discussed in this design chapter. Weighing platform
The weighing platform is the area where the raw material used for the starch extraction is unloaded and weighed. After the weighing platform, the potato is unloaded to the sampling and washing section. Figure 3.9 shows the mass balance over the weighing unit.
Figure 3.9: Mass balance diagram over weighing unit Sampling and dry washing
The potato is conveyed to the sampling section with a total volume of 10.4 m 3 where they are sorted and sent to the dry washing unit for cleaning before storage. This will avoid any problem of contamination inside the storage area which might consequently cause possible loss of raw materials. Figure 3.10 shows the mass balance over the sampling and dry washing unit.
Figure 3.10: Mass balance diagram over sampling and dry washing unit Storage area
The storage area is the area where the selected potato for the process plant will be stored for the minimum period. The turnover of the storage area should be fast and the oldest potato should be processed first (International Starch Institute, 2006). The reception area has an overall volume of 1060 m 3. An additional 25% volume was considered as an assumption for the safety so that any excess of potato can be stored during period of maintenance within the plant. A cold storage area should be available to avoid early sprouting of the tuber in any condition of plant shut down. The storage area is a well ventilated rectangular area and made of either concrete or steel. Figure 3.11 shows the mass balance over the storage area.
Figure 3.11: Mass balance diagram over reception area Rotary bar screen
The rotary bar screen removes the stones and unwanted materials that might still be attached to the tuber prior to the washing section. Figure 3.12 shows the mass balance over the rotary bar screen unit.
Figure 3.12: Mass balance diagram over rotating bar screen Rotary washer
The rotary washer is the unit where the potato tubers are washed intensely to remove all the unwanted dirt and stones. The rotary washer is fed with fresh process water to be cleaned. The wash water (containing the dirt and unwanted components) is then filtered and recycled through a rotary screen and passed through a settling basin of sand to remove the unwanted components of dirt. Any loss of process water along the unit line is compensated by the recycled water. The water in the rotary washer is added by pressure nozzles in the final step and a counter current flow is adopted for the washing. The pressure ensures that the maximum amounts of unwanted materials are removed from the process flow. The mass balance over the rotary washer is shown in Figure 3.13.
Figure 3.13: Mass balance diagram over rotary washer unit Stone catcher
The potato passes through a stone catcher along the washing line so that the stones and soil collected are removed. The difference in weight is used for the removal of stones
(International Starch Institute, 2006). Water level in the stone catcher is k ept low so that the potato tubers do not float. Figure 3.14 shows the mass balance over stone catcher unit.
Figure 3.14: Mass balance diagram over stone catcher unit Rotary screen peeler
The rotary screen peeler is the unit where the tuber is peeled prior to rasping. The peeled tubers are then fed to the rasper through a buffer bin, allowing a constant mass flow rate of tuber along the process line. The peeler that can be used for the unit is similar to the Rootveg peeler and polisher from the Haith Tickhill Group of companies. Figure 3.15 illustrates the mass balance over the rotary screen peeler. The peeled potato is then fed to the next unit, the rasper and mixing unit, through a buffer bin to ensure that the mass flow rate is uniform. The peels obtained from the potato will be sent to an organic compost company for further processing. It can then be used as an organic fertilizer in the potato agricultural lands instead of chemical fertilizers (International Starch Institute, 2006).
Figure 3.15: Mass balance diagram over rotary screen peeler and buffer bin unit Rasping unit
Rasping is the action of opening the tuber to release the starch granules inside the cells. The rasper unit, with a volume of 272.5 m 3, is the direct rasping equipment and the potato is only passed through this unit once. Cold water, from a feeding tank with a total volume of 118 m3, is added to the rasping unit at a temperature of 4 oC (Thava Vasanthan, 2001). Figure 3.16 shows the mass balance over the rasping unit.
Figure 3.16: Mass balance diagram over rasper and mixer unit Sulphur addition
A Sulphur component, in the ratio of 0.01% (w/v) to the water, is added to the rasped sweet potato to avoid oxidation of the tuber upon rasping. The Sulphur component added is the Sodium Metabisulphite and is added from its dissolution tank, with a 4.5 tons storage capacity, by a feeding pump. Refining unit
I.
Rotating conical sieves
There are two rotating conical sieves used in the first unit for the preliminary sieving of the rasped potato for separating the milk starch from the pulp and fibres of the tuber. The
residue left after separation is used in an auxiliary processing plant where cattle feed can be produced (International Starch Institute, 2006). II.
Hydrocyclone
Hydrocyclone is used for the extraction of only the starch from the milk starch obtained after removal of fiber and pulp. The starch granules are collected at the underflow because they are heavier than water while the fruit juice of the potato is removed in the overflow. III.
Continuous rotating vacuum filter
The moist starch from the previous section is then dried by a continuous rotating vacuum filter. Figure 3.17 shows the principle of the continuous rotating vacuum filter and the equipment.
Figure 3.17: Continuous rotating vacuum filter IV.
Flash dryer
The flash dryer is used in the process plant to dry the starch extracted. A warm air of 35oC to 40oC is forced at the bottom of the flash dryer while the starch is dropped from the top of the machine. The warm air cause the water in the starch to be dispersed and the dried moist starch is accumulated at the bottom. The mass balance diagram over the refining unit is shown in Figure 3.18.
Figure 3.18: Mass balance over the refining unit 3.5.3 Starch-based polymer production Hydrolysis of starch
The hydrolysis of the starch extracted from the sweet potato is subjected to water and acid hydrolysis. A heat source between 90oC to 180oC (Vilpouxet al., 2003) is used in the hydrolysis process. A plasticizer, in the form of glycerol, is also added for the process. The hydrolysis reaction is carried out in a closed tank of 94m 3 under atmospheric pressure. The tank is made of steel to resist the mild acid corrosion that might occur. The tank consists of rotating blades to ensure proper mixing of the ingredients for the polymer production. The mass balance over the hydrolysis unit is illustrated in Figure 3.19.
Figure 3.19: Mass balance diagram over hydrolysis tank Dryer and pelletizer
This unit ensures that the wet polymer produced in the previous section is properly dried in an oven or incubator at a temperature of 40 oC and transformed to smaller pellets of polymer. The mass balance over the unit is shown in Figure 3.20.
Figure 3.20: Mass balance diagram over the polymer dryer and pelletizer unit 3.5.4 Starch-based biodegradable plastic film production This unit consists of the extrusion unit, the film and surface treatment unit and the final distribution unit. 1. Extrusion unit The pellets of the starch polymer, with a possible blend, in the ratio of starch to Polylactic acid (PLA) additive of 70:30 (Qi Fang and Milford A. Hanna, 2000), are first melted and then extruded through a conventional plastic extruder to produce the starch based plastic film to consequently manufacture the plastic carry bags. The melted polymer is forced through a die (depending on the size of the final plastic
product). Compressed air is used for the extrusion with a die of range φ120φ300 (Wenzhou Zhudian Machinery Makes Co., Ltd, 2011). The thickness of starch-based plastic film produced is 20microns. The mass balance over the extrusion unit is as shown in Figure 3.21.
Figure 3.21: Mass balance diagram over extrusion unit 2. Film and surface treatment unit The starch-based plastic film produced is then treated in the film and surface treatment unit to ensure that the final product can be printed for use as carry bags. The mass balance over the unit is as illustrated in Figure 3.22.
Figure 3.22: Mass balance diagram over the film and surface treatment unit 3. Distribution unit The distribution unit is the unit where the starch biodegradable plastic film produced from the extrusion unit is cut and manufactured into the carry bags for commercial use. The mass balance over the unit is as follows:
Figure 3.23: Mass balance diagram over distribution unit
3.6 Preliminary economic analysis over the starch-based plastic film process plant design The economic analysis of the biodegradable plastic process plant was estimated by calculating the following: 1. Purchase Equipment Cost (PEC) 2. Total Direct Cost (TDC) and Total Indirect Cost (TIC) 3. Fixed Capital Investment (FCI) 4. Total Capital Investment (TCI) 5. Total Product Cost (TPC) 6. Profit or Loss 7. Pay Back period 8. Internal Rate of Return (IRR) The method used, such as the equations and relationships, for the economic estimation was from the book Plant Design and Economics for Chemical Engineers, 4th Edition, Max S. Peters, Klaus D. Timmerhaus, Professors of Chemical Engineering, University of Colorado, , 1991, McGraw-Hill International Editions (Refer to appendix). 3.6.1 Purchase Equipment Cost (PEC) The price of the different equipment for the plant were acquired from various industries specified in the field of biodegradable plastic production. The cost were converted to Mauritian rupees (Rs) from Dollars (USD) using the following assumption:
The currency conversion factor of 29.10 Rupees (Rs) for one dollar (USD) was
used. (Currency convertor, 9th December 2015) Equation 1: Conversion = Price in Dollar (USD) x Currency Conversion factor
= USD x Rs 36.20 Some of the equipment costs were estimated by using the equation from Estimating Equipment Costs by Scaling (S. Peters et al., 1991 ). The equation could be used where only a range of ten times the initial capacity was possible. Equation 2: Cost of equipment A = Cost of equipment B x
) (
0.6
3.6.2 Total Direct Cost (TDC) and Total Indirect Cost (TIC) The TDC and the TIC were then calculated by using the typical percentages of Fixed Capital Investment values for TDC and TIC segments for multipurpose plants additions to existing facilities from Ratio factors for estimating capital-investment items based on delivered equipment cost (S. Peters et al., 1991). a) Direct costs The equation 3 was used to find the direct cost. Equation 3: Direct Cost = Percentage used x Purchased Equipment Cost
b) Indirect costs The equation 4 was used to find the indirect cost. Equation 4: Indirect Cost = Percentage used x Total Direct Cost
3.6.3 Fixed Capital Investment (FCI) The FCI was calculated by using the following equation:
Equation 5: Fixed Capital Investment = Total Direct Cost + Total Indirect Cost FCI = TDC + TIC
3.6.4 Total Capital Investment (TCI) The TCI was calculated from Ratio factors for estimating capital-investment items based on delivered equipment cost (S. Peters et al., 1991, Page 183) by using equation
6. Equation 6: Total Capital Investment = Fixed Capital Investment + Working Capital TCI = FCI + WC
Assumption: The percentage of the WC assumed was 10% of the TCI. When the WC represents a percentage of 10%, TCI = FCI + 0.01 TCI
3.6.5 Total Product Cost (TPC) The TPC was derived from the Ratio factors for estimating capital-investment items based on delivered equipment cost (S. Peters et al., 1991, Page 183).
3.6.6 Profit or Loss The profit or loss met by the process plant was found by deducting the annual TPC from the sales as calculated by using equation 7. Equation 7:
Profit/Loss = Revenue – TPC
3.6.7 Payback The payback period of the process plant was determined by using the equation 8. Equation 8: Payback period =
3.6.8 Internal Return of Rate (IRR) The IRR measures the prosperity of an investment and was calculated by using the equation 9.
Equation 9:
− 0 ∑ (1 + ) =
Where: k: is the internal rate of return (IRR) t: is the time period, years CFo: is the initial cash investment, Rs CFt: is the net cash flow at period t, Rs
Chapter 4:
Results and Discussion
4.1 Chemistry behind the formation of starch based bioplastic Starch is made of long chains of glucose molecules. There are two shapes or molecules: amylose which is a straight molecule and amylopectin which has a branched s hape. The
amylose and amylopectin molecules aggregate into small particles called granules. When making the plastic film, the chains of molecules in starch line up and bond in an ordered fashion (due to hydrogen bonding) to make a strong material. Straight chained amylose molecules form a more ordered, and stronger, plastic film, than the branched amylopectin molecules that are difficult to align. In this experiment, dilute hydrochloric acid is added to an aqueous solution of starch to break down the branched amylopectin molecules into straight chained amylose molecules. Once the starch solution is acidified, it is heated to boiling. As the solution is heated, the starch becomes soluble in the water and loses its semi-crystalline structure as the starch granules swell with water. This creates a paste that is highly viscous and the process is known as gelatinization. As the paste cools, the water is expelled and the amylose molecules hydrogen bond to form a semi-crystalline structure again resulting in a brittle plastic film. To improve the flexibility of the samples, other chemicals can be added to the solution before heating. Glycerol is a small molecule that is hygroscopic (water attracting). When glycerol is added to the starch mixture, it traps water in the starch chains making it less crystalline, and consequently less brittle. Sugar can delay gelatinization by competing with starch to absorb water. Glue will increase the flexibility of the sample, while keeping a high tensile strength.
4.2 Starch content of raw potato The average density of potato was found to be about 960 kg/m 3 while the average mass of starch based polymer from 15 grams of starch was around 44.8 grams. This characterizes an overall percentage of 31.7% of the total initial potato used. The value for the mass of starch obtained is in accordance with the value from the literature review. If from literature review, starch represents 32% of potato, then there is a loss of around
0.3% from the potato. Extraction of starch can be carried out by either one of the following mediums: water, alkali or enzymatic. Water is the commonly used medium for the extraction of starch from soft tissues such as from tubers. This was the method chosen for the starch extraction in this study. However, according to a study on enzymatic extraction of starch from potato (J. Kallabinski, 1991), the rate of starch extraction can be increased by 90% to 93%. This medium of extraction was not chosen because of the high energy requirement and requires significant control of the process parameters such as for the temperature and pH.
4.3 Number of starch-based biodegradable plastic carry bags. The number of starch-based plastic carry bags produced from the 10 tons of potato per day being processed is 356, 204 per day or around 117 million starch-based plastic carry bags with the proposed dimension of 30cm by 45cm. From a recent article (Article Base, 2007) the amount of plastic carry bags consumed for the year 2006 was 113 million. The type of plastic being produced and consumed in Mauritius since the law was enforced is the degradable plastic. However according to a recent study (R. Mohee et al., 2006) this type of degradable plastic, even though a biodegradable additive was added during the production process, remained unaffected after 55 days of composting. Also, the study concludes that starch-based plastic would completely degrade in a period of 60 days when exposed in controlled and natural composting environments. The positive aspects of the starch-based plastic film underlined shows that it can be used to slowly substitute the degradable plastic in order to avoid environmental problems. Moreover with the processing of 10 tons per day of sweet potato in the process plant, additional agricultural lands would be required in the island to account for the yearly requirement of the plant.
4.4 Economic analysis of the process plant Table 4.1 shows the results of the economic analysis of the starch-based carry bags process plant.
TABLE 4.1: ECONOMIC ANALYSIS SUMMATION TABLE
Economic feature calculated
Value
Purchase Equipment Cost (PEC)
Rs 21,749,997
Total Direct Cost (TDC) and Total TDC: Rs 41,977,494 Indirect Cost (TIC)
TIC: Rs 26,099,996
Fixed Capital Investment (FCI)
Rs 68,077,491
Total Capital Investment (TCI)
Rs 75,641,656
Total Product Cost (TPC)
Rs 164,170,639
Sales/ year
Rs 182,198,346
Profit or Loss
Rs 18,027,707
Pay Back period
4.20 years
Internal Rate of Return (IRR)
23%
From the economic analysis, a final payback period of 4.20 years was obtained for a total profit of Rs 18,027,707 per year and a Total Capital Investment (TCI) of Rs 75,641,656. The production of approximately 113 million of starch-based biodegradable plastic carry bags was possible per year at a selling price of Rs 1.55 thus bringing revenue of Rs 182,198,346 to the process plant per year. In addition to the revenue already obtained from the starch-based carry bags, the production of cattle feed from the potato fiber residue and compost from the potato peels can bring supplementary revenue to the plant.
4.5 Mechanical testing of the bioplastic samples. The mechanical testing was carried out at the metrology lab from the mechanical department at the University of Mauritius. The Universal texting machine was used to perform several physical tests and hence obtaining values for the elongation at break and at peak, force at break and at peak, strain at break and peak, stress at break and at peak, young’s modulus, time to failure and finally the time to peak. The standard ISO 18872 was adopted for the several tests where a pull-off speed up to 20 mm/min were achieved. In addition, the use of direct extension measurement on the specimen were possible, allowing informative stress-strain diagrams to be generated.
Fig 4.1: Graph of force against Elongation for sample 1
Fig 4.2: Graph of stress against strain for sample 2
Fig 4.3: Graph of Stress against strain for sample 3 It was observed that this typical bioplastic could resist a force up to 1 Kg and hence it has a good strength.
Chapter 5:
Conclusion
This study was carried out with the aim to investigate the potential of producing starch based plastic films and consequently plastic carry bags from potato starch in Mauritius. The tensile properties of the starch-based polymer were observed to be higher when the thickness of the polymer was increased. However, according to the law promulgated on plastic carry bags in Mauritius, the thickness should be at 20microns. The tensile properties can therefore be improved with the addition of additives such as Polylactic acids (PLA) or fiber additives. Besides, the feasibility of the proposed process plant for the production of the starch-based was also evaluated. This study showed that the product realization was viable with a payback period of 4.20 years. This was achieved with a TCI of Rs 75,641,656, TPC of Rs 164,170,639 and revenue of Rs 18,027,707 on the production per year. The production of approximately 117millions of starch-based plastic carry bags was possible per year at a selling price of Rs 1.55. The legislative norms governing the starch-based plastic carry bags were assumed to be similar to those of degradable plastic bags under the Environmental Protection Act 2004 governing ‘Plastic Carry Bags’ , made by the Minister under section 96 of the environment Protection Act 2004. Moreover, with a process plant, for a total capacity of 10 tons per day of potato, additional agricultural lands would be required in the island since the production of the tuber is 435 tons at the present time for the year. This would consequently encourage the agricultural sector and create job opportunities. To conclude, the production of starch-based plastic film is a viable industry even though for the time being it will still be dependent on petroleum products such as energy resources for the machine operation. However, with the increasing influence for the environment concern, the use of renewable resources such as starch-based plastic products will be an obligation across the world.
5.1 Recommendations and Future works The recommendations identified for the project are as follows: It is recommended to use fresh potato starch for better quality of the bio plastics. The waste extracted from the potato remaining and fibers could be used as
compost or cattle feed. Cheaper and less risky form of acid could be used instead of hydrochloric acid
such as acetic acid. Sorbitol is a plasticizer that could be used as a substitute to glycerol in the process
of production. The starch from the potato could be extracted by the two other means namely alkali
or enzymatic extraction to determine the percentage extraction as compared to water extraction. The detailed design of the process plant could be worked out to provide a more
precise production illustration of the plant.
The future works that can be carried out in the same line of study as this project can be as follows: A Life Cycle Assessment (LCA) study between the starch-based biodegradable
plastic carry bags and degradable plastic carry bags can be carried out to determine the potential impacts related with the inputs and outputs of both process plants. A sustainability study of the starch-based plastic product can be performed to
determine if it is economically, environmentally and socially acceptable. Other sources can be used to produce different types of bioplastics, for example,
the production of PHB or PHA from the digestion of microorganisms can be investigated.
Chapter 6:
1. CO2G
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Appendix: Economic analysis The economic feasibility of the biodegradable plastic plant was covered in this part of the Appendix. The purpose of this part was to present a preliminary technical and economic feasibility study for the process plant. Two main aspects were examined, namely the total capital investment of the process plant and the payback period. The economic analysis of the biodegradable plastic process plant was estimated by calculating the following: 1. Purchase Equipment Cost (PEC) 2. Total Direct Cost (TDC) and Total Indirect Cost (TIC) 3. Fixed Capital Investment (FCI) 4. Total Capital Investment (TCI) 5. Total Product Cost (TPC) 6. Profit or Loss 7. Pay Back period 8. Internal Rate of Return (IRR) The method used, such as the equations and relationships, for the economic estimation was from the book of Max S. Peters, Klaus D. Timmerhaus, 1991, Plant Design and Economics for Chemical Engineers. A1. Purchase Equipment Cost The first aspect of the economic analysis was the Purchase Equipment cost. The prices of the equipment to be used in the process plant were first obtained from different industries specialized in the field of starch extraction and biodegradable plastic production. Table A.1 shows the different equipment used and their industrial sources.
Table A1: Equipment cost and the industrial source
Equipment Total
Industrial Source
Amount
Price (USD)
Conveyor
Kaifeng Sida Agricultural 2 Products Equipment Co., Ltd
3400
Cleaning cage
Kaifeng Sida Agricultural 1 Products
1060
Crusher (rasper)
Kaifeng Sida Agricultural 1 Products Equipment Co., Ltd
3500
Round Sieve
Kaifeng Sida Agricultural Products Equipment Co., Ltd
4
9200
Slurry Pump
Kaifeng Sida Agricultural 5 Products Equipment Co., Ltd
7500
Round Sieve
Kaifeng Sida Agricultural 1 Products Equipment Co., Ltd
2300
Residue Pump
Kaifeng Sida Agricultural 5 Products Equipment Co., Ltd
6500
Vortex
Kaifeng Sida Agricultural 18 Products Equipment Co., Ltd
63000
Desander
Kaifeng Sida Agricultural 2 Products Equipment Co., Ltd
800
Desander Pump
Kaifeng Sida Agricultural 1 Products Equipment Co., Ltd
1600
Vacuum
Kaifeng Sida Agricultural 1 Products Equipment Co., Ltd
9600
Kaifeng Sida Agricultural 1 Products Equipment Co., Ltd
26000
(Rotating sieve)
(Dewatering)
Assembly (Hydrocyclone)
dehydrator Airflow dryer
Electricity
Kaifeng Sida Agricultural 5 Products Equipment Co., Ltd
7000
Transfer pump
Kaifeng Sida Agricultural 5 Products Equipment Co., Ltd
3000
Hydrolysis tank
Hangzhou Pharmaceutical Co., Ltd
Dryer
KC Printing (Group) Limited
Granulating and
Jiangsu Lianguan Science &
chamber
Haishun 1 Machinery Machine 1
191076
3850
1
152947
recycling unit
Technology Co., Ltd.
Plastic extruder
Wenzhou Zhudian 1 Machinery Makes Co., Ltd.
250808
Film and surface
Tianrun Machinery Co., Ltd.
4282
Development
1
treatment For the conversion of the dollar currency to the Mauritian rupee, the equation three was used: The currency conversion factor of 29.10 Rupees (Rs) for one dollar (USD) was used. (Fx-rate, 7th March 2016) Conversion = Price in Dollar (USD) x Conversion factor
= USD x Rs 29.10 The calculation for the conversion for the conveyor used in the process was as follows: Conveyor
i.
The total price of the conveyor = 3400 USD
ii.
Currency conversion used is 29.10 Rupees (Rs) for one dollar (USD)
iii.
Price of the conveyor = Rs(3400 x 29.10) = Rs 98, 940
The price conversions for all the equipment were done as for the conveyor. The table
A.2 shows the conversion for the equipment used. Table A2: Conversion table for purchased equipment
Equipment List
Conversion of USD to Rs Total Price of equipment (Rs)
Conveyor
3400 x 29.10
98,940
Cleaning cage
1060 x 29.10
30,846
Crusher
3500 x 29.10
101,850
Round Sieve
9200 x 29.10
267,720
Slurry Pump
7500 x 29.10
218,250
Round Sieve
2300 x 29.10
66,930
Residue Pump
6500 x 29.10
189,150
Vortex Assembly
63000 x 29.10
1,833,300
Desander
800 x 29.10
23,280
Desander Pump
1600 x 29.10
46,560
Vacuum dehydrator
9600 x 29.10
279,360
Airflow dryer
26000 x 29.10
756,600
Electricity chamber
7000 x 29.10
203,700
Transfer pump
3000 x 29.10
87,300
Hydrolysis tank
191076 x 29.10
5,560,306
Dryer
3850 x 29.10
112,035
(Hydrocyclone)
Granulating and recycling 152947 x 29.10 unit
4,450,758
Extruder
7,298,499
Film and treatment
250808 x 29.10 surface 4282 x 29.10
124,613.61
The Purchased Equipment Cost (PEC) was calculated by adding the different price of the equipment and the total purchased equipment cost was Rs 21,749,997. A.2 Equipment cost estimation
Some of the equipment costs were estimated by using the equation from Estimating Equipment Costs by Scaling (S. Peters et al., 1991, Page 169). The equipment that were estimated by scaling are: i. Hydrolysis tank ii. Granulating and recycling unit iii. Extruder unit iv. Film surface treatment The equation four was used for the estimation of the costs of the equipment.
1. Hydrolysis tank i. Capacity of hydrolysis tank from quotation = 10kg/hr ii. Capacity of hydrolysis tank required = 100kg/hr iii. Cost of equipment obtained = 100 000 USD iv.
Estimation of hydrolysis tank required:
Table A.3 shows the different available capacity and cost of the equipment
Table A.3: Capacity and cost of equipment
Equipment
Capacity
Wanted
Actual
Final
capacity
price
Price
Hydrolysis tank (L)
20000
94000
75500
191076
Granulating and recycling
300
2000
49000
152947
100
1000
63000
250808
Film surface 120 treater (kg/hr)
1000
1200
4282
unit (kg/hr) Extruder (kg/hr)
A.3 Total Direct Cost (TDC) and Total Indirect Cost
The TDC and the TIC were then calculated by using the typical percentages of Fixed Capital Investment values for TDC and TIC segments for multipurpose plants or large additions to existing facilities from Cost factors in Capital Investment (Max S. Peters et al., 1991, Page 183) A.3.1 Direct costs The equation was used to find the direct cost. Direct Cost = Percentage used x Purchased Equipment Cost
Table A.4 shows the typical percentages and cost calculated for the direct cost.
Table A.4: Total Direct Cost calculations
Direct Costs
% taken Equipment 0.39
Purchased Installation
PEC (Rs)
Calculations
Costs (Rs)
21,749,997 39% x PEC
8,482,499
Instrumentation & Control
0.13
21,749,997 13 % × PEC
2,827,500
Piping
0.31
21,749,997 31 % × PEC
6,742,499
& 0.10
21,749,997 10 % × PEC
2,175,000
Building & Services
0.29
21,749,997 29 % × PEC
6,307,499
Yard Improvement
0.10
21,749,997 10 % × PEC
2,175,000
Service facilities
0.55
21,749,997 55 % × PEC
11,962,498
Land
0.06
21,749,997 6 % × PEC
1,305,000
Electrical Materials
equipment
Total Direct Cost (TDC)
41,977,494
The TDC was obtained by adding all the direct cost and the value is Rs 41,977,494. A.3.2 Indirect costs The equation was used to find the indirect cost. Indirect Cost = Percentage used x Total Direct Cost
Table A.5 shows the typical percentages and cost calculated for the indirect cost.
Table A.5: Total Indirect Cost calculations
Indirect Costs
% taken
PEC
Calculations
Costs (Rs)
Engineering & Supervision
0.32
21,749,997 32 % × PEC
6,959,999
Construction expenses
0.34
21,749,997 34 % × PEC
7,394,999
Contractors fee
0.18
21,749,997 18 % × PEC
3,914,999
Contingency
0.36
21,749,997 36 % × PEC
7,829,999
Total Indirect Cost (TIC)
26,099,996
The TIC was obtained by adding all the indirect cost and the value is Rs 26,099,996. A.4 Fixed Capital Investment (FCI)
The FCI was obtained by using the equation: Fixed Capital Investment = Total Direct Cost + Total Indirect Cost FCI = TDC + TIC
The FCI of the process plant is Rs 68,077,491. A.5 Total Capital Investment (TCI)
The TCI has the following equation: Total Capital Investment = Fixed Capital Investment + Working Capital TCI = FCI + WC
Assumption: The percentage of the WC assumed was 10% of the TCI.
When the WC represents a percentage of 10%, TCI = FCI + 0.01 TCI
Then: TCI = (FCI/ 0.9) TCI = Rs (68,077,491/ 0.9) = Rs 75,641,656 Therefore WC = Rs (0.1 x 75,641,656) = Rs 7,564,166 A.6 Total Product Cost (TPC)
The TPC was calculated from the from Ratio factors for estimating capital-investment items based on delivered equipment cost (S. Peters et al.,1991, Page 183) and the calculations are shown in Table A.6. Table A.6: Total Product Cost (TPC) calculations
Raw materials:
Calculations
(Rs)
potato
Rs 20 x 10000 kg x 66,000,000 330 days
(Rs)
Hydrochloric acid Rs 20137.20 x 1.621 10,770,344 metric ton x 330 days Glycerol
Rs 20.37 x 1.907 12,817 metric ton x 330days
Sodium
Rs1000 x 9.70kg x
metabisulphite
330days
3,199,6
Total
Operating (OL) Direct Labor
Labor 10 % TPC
Clerical 10 % OL
79,982,764
0.1 TPC
0.01 TPC
Utilities
10 % TPC
0.1 TPC
Maintenance &
5 % FCI
3,403,875
Repairs
Operating Supplies
0.5 %
FCI 340,387
Direct Production
83,727,026 0.21 TPC
Cost
Fixed Charges
10 % TPC
0.1 TPC
Plant Overhead
10 % TPC
0.1 TPC
+
0.2 TPC
Cost
Manufacturing
83,727,026 0.41 TPC
cost
Administrative
3 % TPC
0.03 TPC
5 % TPC
0.05 TPC
+
Cost Distribution & Selling General expenses
0.08 TPC
Total Product Cost
83,727,026+ 0.49 TPC
(TPC)
TPC = Rs (83,727,026+ 0.49 TPC) TPC = Rs 164,170,639 The value obtained for the TPC was Rs 164,170,639. A.7 Sales
The sales of the plastic carry bags produced from the starch based polymer were sold at Rs 1.55 and the total sales obtained from the sale of 356204 starch-based biodegradable plastic carry bags per day was:
Total sales = (356204 x Rs 1.55 x 330 days)
= Rs 182,198,346 The revenue for the process plant is Rs 182,198,346. A.8 Profit/Loss
The Profit/ Loss of the process plant was calculated by using equation: Profit/Loss = Revenue – TPC
When the revenue of the process plant is Rs 182,198,346 and the TPC is Rs 164,170,639, The Profit encountered by the process plant is = Rs (182,198,346 – 164,170,639) = Rs 18,027,707 After calculating the revenue and total product cost, the process plant obtained a profit of Rs 18,027,707. A.9 Payback period
The payback period of the process plant was determined by using the equation:
When: i. TCI of the plant is Rs 75,641,656, ii. And the Profit obtained per year is Rs 18,027,707, The payback of the process plant = Rs (75,641,656 / 18,027,707)
= 4.20 years A.9 IRR
The IRR measures the prosperity of an investment and was found by using the equation:
Where: k: is the internal rate of return (IRR) t: is the time period, years CFo: is the initial cash investment, Rs CFt: is the net cash flow at period t, Rs
The IRR obtained for the starch-based biodegradable plastic carry bags process plant was calculated as shown in Table H.7. The IRR obtained for the prosperity of the investment is 23%.
ANNEX 1 UNIVERSITY OF MAURITIUS FACULTY OF ENGINEERING PROJECT/ PROPOSAL SYNOPSIS
Department: Chemical and Renewable Energy Engineering Academic Year: 2015/2016 Soomaree Keshav 1114132 Production of Bioplastics Aims and Objectives: The aim of this project is to: Identify a suitable and sustainable feedstock which is locally available and to
investigate the means of producing bioplastics from it. The primary objective is to: Find a sustainable alternative to conventional plastics made from non -
renewable resources and to be able to economically producing bioplastics from natural sources obtained throughout the year. To achieve this, some physical, mechanical and chemical tests should be d one
on different samples produced.
Preparation of feed stocks : Extraction of potato starch from peel and flesh Production of bioplastics experiments Testing of produced material Physical and mechanical tests
: At least once every two weeks : 10/08/15 : 07/04/16 GANTT CHART
Aug Intro/Lit Rev Preparation of feed stocks Setup of equipment Running of experiments Data collection Analysis of data Writing of Project Submission
Name of Supervisor: Mr A.K.Ragen
Student Signature:
Date:
Supervisor Signature:
Date:
Sep
Oct
Nov
Dec
Jan
Feb
Mar
ANNEX 2
UNIVERSITY OF MAURITIUS FACULTY OF ENGINEERING
PROGRESS LOG Student Name
: Soomaree Keshav
Student ID
: 1114132
Department
: Chemical Engineering
Programme
: Chemical and Environmental Engineering
Title of Dissertation :
Production of Bioplastics
Supervisor
:
Mr. A.K. Ragen
Project Coordinator :
Mr. A.K. Ragen
• • •
• •
Your Progress Log serves as a record of your transferable skills and participation and attainment as a student for dissertation purposes. Its purpose is to help you to plan your own dissertation and to record the outcomes. As well as gaining valuable skills, you will find that the information accumulated in this Log will prove helpful during the write up of the dissertation. The document belongs to you and it is your responsibility to keep it up to date. It is your responsibility to ensure your supervisor is aware of the dissertation activities you have undertaken.
You should sign the appropriate statement below when you submit your Progress Log:
I confirm that the information I have given in this Log is a true and accurate record:
Signed: ………………………………………
Date: ………………
