Training Report on “MANUFACTURING “ MANUFACTURING OF SUGAR ” At “MAWANA SUGAR WORKS”
Submitted in partial fulfillment of the requirements for the degree of Bachelor of Technology In Chemical Engineering
By SHIVAM MITTAL Roll No.: 1012851035
Department of Chemical Engineering Bharat Institute of Technology, Meerut, India Mahamaya Technical University, Noida, India 2012-2013
CERTIFICATE
This is to certify that Mr. Shivam Mittal (Roll No.-1012851035), B.Tech student of Bharat Institute of Technology, Meerut under Mahamaya Technical University, Noida, has
successfully completed one week Industrial Training at “MAWANA SUGAR WORKS” towards partial fulfillment of his academic requirements for the degree of Bachelor of Technology In Chemical Engineering. He worked on the project ―Manufacturing of Sugar ‖. It is an original work carried out by the candidate himself under my Supervision and guidance. This work has not been yet submitted to any other university for the award of Degree/Diploma to the best of my knowledge.
We wish him a bright and successful career.
Sanjeev Mishra (Head Trainer)
CERTIFICATE
This is to certify that Mr. Shivam Mittal (Roll No.-1012851035), B.Tech student of Bharat Institute of Technology, Meerut under Mahamaya Technical University, Noida, has
successfully completed one week Industrial Training at “MAWANA SUGAR WORKS” towards partial fulfillment of his academic requirements for the degree of Bachelor of Technology In Chemical Engineering. He worked on the project ―Manufacturing of Sugar ‖. It is an original work carried out by the candidate himself under my Supervision and guidance. This work has not been yet submitted to any other university for the award of Degree/Diploma to the best of my knowledge.
We wish him a bright and successful career.
Sanjeev Mishra (Head Trainer)
ACKNOWLEDGEMENT
At the very outset, I am highly indebted to MAWANA SUGAR WORKS, Mawana, Meerut for Sugar” at their giving me an opportunity to carry out my project on “Manufacturing of Sugar”
esteemed organization. I would specially thank Mr. Sanjeev Mishra(Head Trainer), MAWANA SUGAR WORKS, Mawana for giving time and guidance throughout my training without whom it would have been impossible to attain success. My heartiest thanks to other trainees and employees at MAWANA SUGAR WORKS for helping me throughout the project tenure. I own my regards to the entire faculty of the department of Chemical Engineering at BHARAT INSTITUTE OF TECHNOLOGY from where I have learnt the basics of Chemical
Engineering and whose informal discussions and able guidance was become a light for me in the entire duration of this work. Not only to fulfill a formality but also to express the feelings in our heart, we put on record our deepest grated and profound indebtedness to all of them who help us by right guidance, upgrading our programming skills, and troubleshooting while doing the assignments. At last but not the least, I would like to pay my sincere regards to the Faculty members for their invaluable support and blessings, which were a vital nec essity for the completion of my project work. As a final personal note, I am grateful to, my parents, who are inspirational to me in their understanding, patience and constant encouragement.
SHIVAM MITTAL ROLL NO: 1012851035
PREFACE
Sugar industry is of significant importance to the Indian economy. While consumption has been growing historically, the production has been cyclical. At present, the sugar industry is regulated across the value chain. The key stakeholders of sugar industry, i.e., farmers, millers, consumers and the government have shared goals of achieving high economic growth, minimizing risks, enhancing farmer miller relationships, meeting growing domestic demand and contributing to the nation's food and energy needs. Factors, such as, cyclicality in the business, cane procurement, manufacturing and sales processes, dependency on the monsoon differentiate the sugar industry from any other industry. Internal audit can go a long way in helping sugar industry in improving their operating efficiency, increasing value for money and finally, their competitiveness, both in the domestic as well as in international markets. Given the changing dynamics of the business landscape as well as emerging technology tools to augment internal audit activities, internal auditors must commit themselves to ongoing education and skill development. Through this Training Report, an attempt has been made to help the readers to understand the basic operations undertaken in sugar industry and the detailed procedures to be undertaken by the engineers in respect of various areas. The Report has been divided into six chapters. Chapter 1 dealt with the company‘s profile. Chapter 2 provides the overview of the sugar industry in India. Chapter 3 discusses the structure of the sugar industry. Chapter 4 explains the various processes involved in sugar industry, such as, sugarcane development and procurement, manufacturing of sugar, and sales and marketing of sugar. Chapters 5 deals with the technology and engineering involved in sugar industry. Chapter 6 provides the waste characteristics and pollution prevention and control. The Report also includes the glossary of terms for explaining the technical terms peculiar to the sugar industry.
GLOSSARY
Ash
The following two types of ash are commonly referred to in sugar production.
Carbonated Ash - This is ash residue which remains after burning at 650 degrees Celsius.
Sulphited Ash - This is ash residue from a sample treated with sulphuric acid which remains after burning at 6 50 degrees Celsius.
Bagasse
The residue left behind sugar cane crushing is referred to as bagasse. There are various types of bagasse obtained after various stages in the milling, diffusing and dewatering stages of sugar production. Bagasse obtained after the first mill is called first mill bagasse and depending on how many milling stages the sugar cane goes through, there may be second mill bagasse, third mill bagasse, etc. Post diffusion stage, the bagasse is known as diffuser bagasse and the very last type of bagasse made after the dewatering stage is known just as bagasse, or some people may refer to it as final bagasse.
Bagasse
Bagasse is a liquid fraction which is decanted from the bagasse after it has
Extract
been blended with water in the cold digester.
Boiling House
Where juices are taken after carbonization or phosphorization to be boiled down
Boiling House
A percentage ratio describing how much pol is recovered in the form of sugar
Recovery
from the mixed juice
Crystal
A measurement describing the mass of crystalline sugar present in a liquid
Content Extraction
A measurement of the percentage ratio of sucrose in mixed juice compared to sucrose in sugar cane
Fiber
It is the solid part of the sugar cane which cannot be dissolved. It is also known as natural fiber.
Filter Cake
It is the material which is removed via filtration during the sugar refining process.
Invert Sugar
When sucrose is hydrolyzed then invert sugar is produced. This is a sugar mixture which is half glucose and half fructose
Juice
Absolute Juice - This juice only exists hypothetically and is the mass of sugar cane minus the mass of fiber. It is not possible to ever completely extract all the sugar and liquid present in the cane.
Clarified Juice - It is the juice which has b een clarified.
Diffuser Juice - It is the juice removed from sugar cane or bagasse diffusers.
First Expressed Juice - The first juice which is extracted by the first two rollers.
First Mill Juice - The first juice extracted from the first mill.
Last Expressed Juice - The last juice extracted b y the last rollers.
Last Mill Juice - The last juice extracted from the last mill.
Mixed Juice - The juice that is pumped to the juice scales from the extraction plant.
Press Water - The liquid removed when diffuser bagasse is dewatered.
Primary Juice - The combined juices prior to treatment.
Residual Juice - The juice present in bagasse apart from the juice in first bagasse.
Secondary Juice - It is the diluted juice which is mixed with primary juice to make mixed juice.
Massacuiet
Crystals and mother liquor which are removed from a vacuum pan as a liquid mixture. There are various grades of Massacuiet determined b y their purity.
Molasses
A thick, dark, sweet, highly viscous substance separated from sugar at the beginning of the refining process.
Mud or Press
This term refers to the sludge type material that is cleaned from the lower
Mud
regions of subsides. This is made up of liquid and insoluble substances.
Sucrose
The form of sugar that is refined from sugarcane a nd sugar beet.
Sugar
This is most often used to describe sucrose.
Sugarcane
A tall, fibrous plant which naturally contains high levels of sucrose, and some glucose and fructose (though these are removed in the refining process). Sugarcane is scientifically classified as being a grass and is a member of the genus Saccharin.
Syrup
In sugar production, this term refers to concentrated juice which has a brix between 60 and 70 percentage
Wash
This is a term which can be used to describe the liquor which is removed after washing, and the liquor removed from magma.
CONTENTS
Acknowledgement…………………………………………………………………………………iii Preface……………………………………………………………………………………………..iv Glossary…………………………………………………………………………………………..v-vii Contents………………………………………………………………………………………….viii-ix List of Figures……………………………………………………………………………………..x
1. Company Profile………………………………………………………………..1 1.1 Core Business…………………………………………………………….1 1.2 Non-Core Business………………………………………………………1 1.3 Location………………………………………………………………….2 1.4 Products………………………………………………………………….2 2. Introduction to Sugar Industry…………………………………………………3 2.1 Product Description and Applications…………………………………...3 2.2 Plant Capacity…………………………………………………………… 4 2.3 Raw Materials…………………………………………………………… 4 2.4 Utilities Required……………………………………………………….. 4 2.5 Industry Description and Practices………………………………………4 3. Structure of Sugar Industry…………………………………………………… 7 4. Key Processes in Sugar Industry………………………………………………9 4.1 Sugarcane Development and Procurement………………………………9 4.2 Manufacturing………………………………………………………….. 12 4.2.1
Sugar Unit……………………………………………………. 12
4.2.2
Cogeneration Unit……………………………………………. 15
4.2.3
Distillery Unit………………………………………………. 16
4.3 Sales and Marketing…………………………………………………...16 5. Technology and Engineering………………………………………………… 18 5.1 Machinery and Equipment……………………………………………. 18 5.2 Land, Building and Civil Works………………………………………19 5.3 Proposed Location……………………………………………………. 19 6. Waste Characteristics……………………………………………………….. 20 6.1 Pollution Prevention and Control…………………………………….. 20 6.2 Target Pollution Loads………………………………………………..21 6.3 Treatment Technologies………………………………………………. 21 7. Conclusion…...……………………………………………………………… 22
Bibliography…………………………………………………………..................................xi
LIST OF FIGURES
1. Business Overview……………………………………………………………… 2 2. Process Flow Diagram of Plantation White Sugar Production………………….5 3. Simplified process flow diagram for cane sugar production……………………6 4. Sugar Cycle…………………………………………………………………….. 7 5. Overview of Integrated Sugar Industry………………………………………… 8 6. Sugar Business Value Chain…………………………………………………… 9 7. Key Steps in Cane Procurement………………………………………………..10 8. Procurement through Mill Gate and Out-centers………………………………11 9. Overview of Sugar Manufacturing……………………………………………..13
1. COMPANY PROFILE
Mawana Sugars Limited (MSL) is the sixth largest private sector sugar manufacturer in India; the Company was formed in December 2003, when it acquired the sugar business of the conglomerate Siel Ltd; besides, Nanglamal Sugar Limited, an erstwhile subsidiary, was merged with MSL with effect from 1.10.04. Mawana Sugars Ltd. is a company formed out of a business restructuring of Siel Limited (erstwhile Shriram Industrial Enterprises Ltd.), an industrial Conglomerate belonging to the Siddhartha Shriram Group. MSL had acquired the sugar business from Siel Limited through a scheme of arrangement approved by the High Court of Delhi. The Group has been operating in the sugar industry for the last 59 years. The Company has three sugar units and one chemical unit. The sugar units are located at Mawana, Titawi and Nanglamal in U.P with capacity of 13000, 10500 and 6000 tcd respectively. The sugar units have bagasse based power plants with total capacity of 116.8MW out of which 47MW power is exportable. The chemical unit is located at Rajpura in Punjab. The unit manufactures caustic soda, chlorine and caustic flakes.
1.1 Core business: Sugar & Power – The Company is primarily in the business of sugar. The Company sells
packed branded sugar though FMCG distribution channel retail outlets in Northern India. Also the Company has appointed dealers to sell refined sugar to institutional buyers‘ viz. Cadbury India Ltd, PepsiCo India Holdings Pvt. Ltd, Glaxo Smith line, Heinz India Pvt. Ltd and other confectionery / pharmacy companies. The three sugar units have bagasse based power plants with total capacity of 116.8MW out of 47MW power is exportable. The Company has power purchase agreement with Paschimanchal Vidyut Vitran Nigam Ltd.
1.2 Non-core business: Chemical – Apart from the above products the Company also manufactures caustic flakes,
chlorine, hydrochloric acid, hydrogen, stable bleaching powder, sodium hypochlorite. Chemical business contributes 24% to the total revenue. In chemical segment, caustic soda is a major product and contributes 16% to the total revenue. The share of revenue from chemical business
of MSL is about 24% of the total revenue. The Company has appointed SBICAPS as an advisor for evaluating strategic options for the chemical business.
Figure 1: Business Overview 1.3 Location:
Mawana Sugars Limited has an installed capacity of 29,500 TCD cane crush and this is spread across manufacturing units at Mawana, Titawi and Nanglamal; these are located in the fertile cane-rich region of West Uttar Pradesh in India. Although Mawana Sugars has been in business for more than 60 years; its Titawi sugar unit (since 1993) and Nanglamal (since 2006) are considered to be amongst the best sugar mills in India. 1.4 Products:
Mawana Sugars pioneered the manufacture of branded retail sugar with its 'Mawana' brand of sugar in India since 1994. Available in retail packs of 1 kg, 2 kg, 5 kg and Rs 5 value pack, the brand has emerged as the largest selling retail sugar pack in India, commanding a premium in a competitive marketplace. Besides, the Company is also a preferred supplier to brand-enhancing institutional giants such as Nestle, Coca Cola, Pepsi, J oyCo, Perfetti, Hamdard, Dabur, Haldiram, GSK, Britannia and Cadburys.
2.
INTRODUCTION
TO SUGAR INDUSTRY
India is the second largest producer of sugar in the world and there are around 637 sugar factories (as on 31.12.2009) operating in India. Indian sugar industry comprises of mix of private and co-operative units and is highly regulated by Central and State government bodies. Most of the private players are listed on stock exchanges. There are several aspects which differentiates Sugar Industry from any other normal manufacturing industry. Some of the peculiar aspects are as follows:
Cyclicality in the business
Sugarcane procurement and governing regulations
Manufacturing process
Sales pattern (mostly unorganized despite huge consumption).
In India, sugar is mainly produced from sugarcane, believed to have been discovered thousands of years ago in New Guinea. From there it spread to South-east Asia and India. Gradually, the process for pressing the sugarcane to extract juice and boiling it to obtain sugar came into existence.
2.1 Product Description and Application: Sugar, or sucrose, is a carbohydrate that occurs naturally in every fruit and vegetable in the plant kingdom. It is the major product of photosynthesis, the process by which plants transform the sugar energy into food. Sugar occurs in greatest quantities in sugar cane and sugar beets from which it is separated for commercial use. The product is mainly used for direct consumption, but also is used to prepare other types of foods such as, biscuits, confectioneries, breweries, soft drinks, etc.
Types of Sugar: Majority of the commercially manufactured sugar is white granulated sugar, which is then
classified as extra coarse, coarse, standard, fine, or extra fine granulated. Other types of sugar, such as brown sugar, are produced with a slight variance from that of white sugar. Brown sugar is made by retaining much of the molasses during processing.
Candy sugar, used mainly by the brewing industry, consists of very large white crystals of sugar. Liquid sugar is made chiefly from cane sugar, while cubed sugar is processed by moulding granular sugar with a sugary liquid to help cement the crystals together.
2.2 Plant Capacity:
The market study reveals that there is high demand for sugar both in local and international market. So, the factors for determining capacity are availability of raw material and minimum economies of scale for the sugar plant. The minimum economic of scale for plantation white sugar production from sugar cane is 47,250 tons per annum. It is assumed that the envisaged plant will partially cover local market demand and will venture into export market for the remaining part of production.
2.3 Raw Materials: 0
The main raw material is sugar cane which requires a temperature range of (32-38)
C and a
minimum rainfall during the growing season. A short dry season is needed before harvesting to maximize sucrose accumulation. SNNPRS is believed to have suitable soil and weather conditions for growing sugar cane. Establishment of sugar industry needs to be integrated with the development of sugar cane farming. In this profile it is assumed that out-growers handle sugar cane supply.
2.4 Utilities Required: Electrical Power: The envisage sugar plant basically utilizes its own electrical power generated
within the plant at the power generation station. This is done by producing steam in the steam generating plant, utilizing the by-product from sugar cane (bagasse) as a main fuel and furnace oil as an auxiliary fuel. The generated steam is let to the power steam turbines and generators to produce the required electrical power. During operation, there are times when no electrical power available from the power generation station (Black -out or during factory start up).During this time and when the sugar plant is not operational(Annual maintenance time), other sources of electrical power (Diesel generator or EPCO grid ) is utilized. For this purpose a total of 4000 kWh electrical power is 3
required from EPCO grid and 20 m of diesel oil is required for diesel generator.
2.5 Industry Description and Practices: The sugar industry processes sugar cane and sugar beet to manufacture edible sugar. More than
60% of the world‘s sugar production is from sugar cane; the balance is from sugar beet. Sugar
manufacturing is a highly seasonal industry, with season lengths of about 6 to 18 weeks for beets and 20 to 32 weeks for cane. Approximately 10% of the sugar cane can be processed to commercial sugar, using approximately 20 cubic meters of water per metric ton (m3/t) of cane processed. Sugar cane contains 70% water; 14% fiber; 13.3% saccharine (about 10 to 15% sucrose), and 2.7% soluble impurities.
Figure 2: Process Flow Diagram of Plantation White Sugar Production
Sugar canes are generally washed, after which juice is extracted from them. The juice is clarified to remove mud, evaporated to prepare syrup, crystallized to separate out the liquor, and centrifuged to separate molasses from the crystals. Sugar crystals are then dried and may be further refined before bagging for shipment. In some places (for example, in South Africa), juice is extracted by a diffusion process that can give higher rates of extraction with lower energy consumption and reduced operating and maintenance costs.
Figure 3: Simplified process flow diagram for cane sugar production
3. STRUCTURE OF SUGAR INDUSTRY
The sugar industry in India is mainly divided into organised and unorganised sector. Sugar factories belong to the organized sector and those who produce traditional sweeteners (Gur and khandsari) fall into unorganized sector. Sugar factories can be further classified into cooperative, private and public sectors. There are around 637 sugar factories (as on 31.12.2009) operating in India with a collective sugarcane crushing capacity of about 21.39 million tones per day. These factories are spread majorly in sugarcane growing states, viz., Uttar Pradesh, Maharashtra, Gujarat, Tamil Nadu, Karnataka and Andhra Pradesh. Uttar Pradesh alone accounts for 32% of the overall sugar production in the nation and Maharashtra's contribution is 28%. The most peculiar aspect of sugar industry is its being seasonal in nature and cyclical variations as demonstrated below:
Figure 4: Sugar Cycle
Due to this, the sugar industry goes through a period of loss (when excess sugarcane is produced) and profit (when there is shortage of sugarcane). The cycle time normally ranges from 4 to 5 years. To reduce the effect of this cycle, now-a-days most of the new units are set-up with a cogeneration of power and distillery unit, so that they can be profitable even when sugar unit is making loss. The integrated aspect of sugar industry is depicted below:
Figure 5: Overview of Integrated Sugar Industry
4. KEY PROCESSES IN SUGAR INDUSTRY The key processes in sugar industry are shown below in the ―Sugar Business Value Chain‖:
Figure 6: Sugar Business Value Chain
4.1 Sugarcane Development and Procurement: Given the huge competition for cane following capacity expansion of most of the mills, a mills’ efforts in terms of cane development activities has a key bearing on cane availability. Hence cane development and procurement department is one of the key departments for any sugar factory. Typically, factories co-ordinate with about 25,000 to 1,00,000 growers/farmers for procurement of sugarcane. Hence, generally as cane development initiatives a factory might come up with the following measures:
Distribution of seeds at subsidized rate/free to cane growers.
Distribution of loans for seed and irrigation facilities.
Distribution of agricultural supplements.
Distribution of fertilizers, insecticides and pesticides.
Conducting general awareness through village meetings
The process of cane procurement starts almost 6 to 7 months in advance starting with survey process. It is highly regulated by state government and every phase is monitored closely.
Figure 7: Key Steps in Cane Procurement Cane Survey:
Cane Survey is the process conducted by team of Sugar Mill‘s member and Co-operative society member (or Government Representative) to assess the amount of cane grown by the growers. Typically, sugarcane crops take about 10 months to 13 months to mature. The survey is carried out close to 5 months before the start of the crushing season, i.e., when the crop has reached almost half of its life.
Calendaring:
After finalization of display, Calendaring is done on the basis of bonding with the grower. Bonding is the quantity of cane that Sugar Mill agrees to purchase from the grower and is based on the following parameters: In case of normal yield : The current year yield is based on the average yield data
provided by the Cane Commissioner or average 2 years supply by the farmer whichever is lower is taken as the yield. General increase : Increasing trend is allowed based on the information provided by
the society. Additional increase : If some farmer expects exceptional increase in the yield,
additional increase would be entered in the system based on the request of the farmer to the Society and its evaluation. Depending upon daily crushing requirement, a calendar is prepared by the Sugar Mill as per the Bonding Policy (‗Satta Niti‘), issued by the State Government. General principles of the policy are as follows:
Farmers can be divided into three categories based on land: Small farmer (0 – 1 Hectare); Marginal farmer (1 – 2 Hectares); Big Farmer (2-5 Hectares).
Based on supply, farmers are divided into two categories: Small (up to 60 quintals); Medium (greater than 60 quintals).
Only 85% of the production can be bonded for any farmer, subject to average quantity supplied by him in the last two years.
Ratoon crop need to be bought within 45 days from start of factory, whereas plant crop need to be bought within 45 days from February.
Bonding with farmer is subject to a cap of 750 qtls, 1500 qtls and 3500 qtls for small, marginal and big farmers.
These principles are liable to change from time to time and, accordingly, the internal auditor should refer to the latest Policy issued by the Government. Once a calendar is prepared then it is given to growers of that area. Cane Out-centers:
Cane out-centers are set up by the mill as directed by the Government, for the convenience of the growers.
Figure 8: Procurement through Mill Gate and Out-centers
A grower can supply cane either at the mill gate or at the out-centers. Sugarcane needs to be crushed within 24 hours of harvesting, else it starts deteriorating (driage of cane, resulting in reduced recovery of sugar from the sugarcane). The distance of out-center from the mill can vary
from 10 kms to around 70 kms or more. Hence, there is need for out-centers so that cane can reach factory/mill at the earliest. Out-center should maintain facilities of weighing bridge and labor for loading and unloading the cane.
Harvesting :
Mature sugar canes are gathered manually and mechanically. Hand cutting is the most common method, but some locations use mechanical harvesters. Canes are cut at ground level, the leaves are removed and the top is trimmed by cutting off the last mature joint. Cane is then tied in bundles and transported to a sugar factory. After cutting, cane deteriorates rapidly, so the sugar cane cannot be stored for later processing without excessive deterioration of the sucrose content.
Cane handling, Cleaning and preparation :
The cane stalks are unloaded from tractors/trucks to the cane table and thoroughly washed (depending on local condition) and let to pass to sets of rotating knives and fibrizers/shredder. The sets of Rotating knives cut the cane into pieces, and fibrizers or shredders rapture the cell of the sugar cane and then transferred to the mills by conveyers for juice extraction process.
4.2 Manufacturing: Sugar industry is energy intensive industry, therefore, apart from sugarcane, steam and electricity are essential for running the mill. For this reason, most of the sugar mills have a cogeneration unit for supply of steam and electricity. 4.2.1 Sugar Unit:
Sugar Mill consists of the following three major areas:
Milling Section
Boiling House
Dryer House
Though milling section and dryer house are continuous processes, boiling house processes mainly occur in batches. Thus, we can term sugar industry as semi-continuous. It takes about 2 to 3 days to complete the whole cycle from cane milling to packing. The norms set up by the management and benchmarking with other sugar industries should be referred to evaluate
manufacturing process of sugar unit, so as to provide reasonable value addition to the management.
Figure 9: Overview of Sugar Manufacturing Milling Section:
Sugarcane is cut into pieces, chopped and fed to mills for extraction of juice. Sucrose (Sugar content), being perishable in nature, starts decomposing right from this stage. It becomes important to add certain chemicals at milling stage to prevent the degradation. Cane is passed through sets of 3 or 4 mills so as to have maximum extraction, before discarding the fiber content as bagasse. Sugar content and moisture are two key parameters for which bagasse needs to be monitored at regular intervals. Bagasse so generated can be directly fed to boiler of cogeneration unit or stored in the yard for use later on. Bagasse is also consumed by the paper industry and can be sold in the open market. The juice extracted in the milling section is sent to clarifiers for further processing.
Boiling House:
The first process of boiling house is clarification. This involves adding chemicals to the juice to remove dirt and other impurities. These impurities are then discarded as press mud which can be used as fertilizer. Clear juice so produced is further concentrated by evaporation through application of steam.
Evaporation and Heating:
The factory can clean up the juice quite easily with slaked lime (a relative of chalk), which settles out a lot of the dirt so that it can be sent back to the fields. Once this is done, the juice is thickened up into syrup by boiling off the water using steam in a process called evaporation. Sometimes the syrup is cleaned up again but more often it just goes on to the crystal-making step without any more cleaning. The evaporation is undertaken in order to improve the energy efficiency of the factory. The syrup is then heated and sulphited to get the required temperature and pH before passing to vacuum pans for further evaporation and crystallization.
Through the centrifuge, molasses is discarded as by-product. The molasses from first set is subject to about three more sets of evaporators and centrifuges before being discarded as molasses, so as to extract maximum amount of sugar. The key parameter to be noted in molasses is the amount of sugar content in molasses, so as to ensure efficiency of boiling hou se.
Crystallization :
The syrup is placed into a very large pan for boiling, the last stage. In the pan even more water is boiled off until conditions are right for sugar crystals to grow. You may have done something like this at school but probably not with sugar because it is difficult to get the crystals to grow well. In the factory the workers usually have to throw in some sugar dust to initiate crystal formation. Once the crystals have grown mixture of crystal and mother liquor (massacuiet) is formed. The sugar crystals are then sent to dryer house.
Dryer House:
Sugar crystals are dried in dryer house and passed through grader so that it can be separated into different grades depending upon the size of the crystals. The crystals are then given a final dry with hot air before being stored ready for dispatch. The dried sugar then passes through a set of graders (sieves) to get the required crystal sizes before bagging of the final product Apart from these three processes, there may be additional refining processes to meet the specific customer requirements.
Effluent Treatment Plant (ETP):
Sugar industries have very stringent guidelines for treatment and disposal of effluent discharged prescribed by State Pollution Control Board (SPCB). The Effluent (waste water) from sugar factory contains organic materials, which will have to be contained and treated prior to disposal to the environment. The objective of treatment of such effluent is to reduce the biological and chemical oxygen demands to allowable levels. This can be achieved by carrying out primary clarification, aeration, fuel clarification and sludge drying. The sludge so obtained can be used as organic fertilizer.
4.2.2 Cogeneration Unit:
Cogeneration unit consist of following three major areas:
Reverse Osmosis (RO) Plant
Boiler
Turbine
Reverse Osmosis (RO) Plant:
Water is required for production of steam; however ground water cannot be directly used as it contains minerals which can damage the boiler when water is converted to steam. Accordingly, it is very important to treat this water in a RO plant or Demineralization of water. The cost of treatment is quite high, hence it is important to check that steam in the process is condensed and used, so as to minimize the amount of make-up water from RO plant. Normally, different factories fix norms/standards for make-up water so as to measure efficiency of the production process.
Boiler:
There are different types of boilers used in the sugar industry. The type of boiler is determined by the type of fuel used and its capacity to produce steam. Normally, bagasse-fed boilers are very common, but there is an increasing trend to use multiple fuel boilers, so that in offseason alternative cheaper fuels can be used to produce electricity. By products from the boiler are boiler ash and flue gas, for which there are prescribed standards by pollution control board so as to minimize damage to the environment.
Turbine:
Steam generated from the boiler is passed in turbine to produce electricity, before being sent to sugar unit. Electricity, thus, generated is used in-house and any excess generation can be sold to State Electricity Boards. A cogeneration unit cannot be run in off-season because if sugar plant is not running, steam generated will have to be vented in atmosphere, which will cause pollution. Hence, these days‘ cogeneration units have installed condenser units so that steam can be condensed back to water in off-season.
4.2.3 Distillery Unit:
The key raw material for distilleries is molasses and steam. Molasses is first fermented in fermentation tank by the application of yeast. Fermentation is the process by which sugar content in the molasses is converted to alcohol. Fermented liquid is then passed through several distillation columns to draw the products as per the requirement. Distillery is highly regulated by the excise laws and all the raw material and finished product are closely monitored by the excise officer [this being a prime raw material for local and branded liquor].
4.3 Sales and Marketing: Sugar:
Sales and marketing in sugar industry is highly regulated by various Laws. Sales of sugar are controlled by Sugar Orders released by Directorate of Sugar every month. Some of the key channels through which sugar is sold are:
Sugar handling agents
Purchase of levy sugar by government and its various agencies
Sugar trading on commodity exchanges
Sale to industrial users
Retail sale
Others:
This includes the sale of Electricity, Distillery products and byproducts like Bagasse, Molasses and Press-mud.
Electricity - Sale of electricity can be either in-house consumption at the plant or township, or transfer to Grid.
Distillery products - Sale of distillery products is regulated by excise laws in India. Currently, it is sold to breweries or chemical manufacturers. In India, though Government has prescribed certain timelines for blending of ethanol with petrol, it is still not mandatory. Once it is done mandatorily, it will give a boost to demand of alcohol.
Molasses - Again highly controlled by Government due to its usage in local hooch manufacture, wherever, mill owners have not put up their own distilleries, it is being sold either to other distilleries or to alternate users like, hooch manufacturers or breweries, etc.
Bagasse - Due to its requirement in boiler running coupled with high cost of transportation, it is being sold by the mill owners to different industrial users (usually on as is where is basis).
Press-mud - It is usually provided free of cost or at a nominal price to the farmers/growers by the mill owners as part of cane development activities.
5. TECHNOLOGY AND ENGINEERING
5.1 Machinery and Equipment:
Machinery and equipment required for the production of sugar are presented in Table 5.1. The total cost of plant machinery and equipment is estimated at about Birr 200 million, out of which Birr 150million is required in foreign currency. Due to the nature of the technology the machinery and equipment are supplied as a package and turn-key project.
Sr. No.
Plant/Station Description
1.
Cane weighment
2.
Cane unloading
3.
Cane preparation
4.
Juice extraction plant
5.
Juice treatment section
6.
Clarification and filtration
7.
SO, and Milk of lime preparation station
8.
Juice heating and evaporation
9.
Graining and crystallizes
10.
Centrifugal machines (Batch & Continuous)
11.
Sugar handling and bagging
12.
Vapor Condensing plant
13.
Steam Generation and distribution plant
14.
Power Generation and distribution plant
15.
Power evacuation system
16.
Bagasse handling system
17.
Automation
18.
Fabrication workshop
19.
Laboratory
20.
Plant water system
21.
Fire fighting system
22.
Piping, insulation and cladding, Chutes, gutters and structures
23.
Sugar Store
24.
Molasses Store
25.
Heating, Ventilation, and Air conditioning
26.
Auxiliary Equipment and Various tanks
27.
Effluent treatment plant Table 1: List of Machinery and Equipment
5.2 Land, Building and Civil Works:
The total land requirement is 50,000 square meters. This includes space required by plant, administration building, auxiliary facilities, etc, and open space for waste treatment plant, open storage for can sugar, molasses storage area, and other utilities. The space requirement by the 2
plant is estimated at 24,000 square meters the cost of land at a lease rate of Birr 1 per m for 95 years is about Birr 50,000. The total cost estimate of building and civil works at unit cost of Birr 2
2800 per m is about Birr 84.0 million. Therefore, the total cost estimate of land, building and civil works is about Birr 84,050,000.
5.3 Proposed Location:
The plant can be located in area where sugar cane can be grown. The area requires a temperature o
o
between 32 c – 38 c, and a minimum rainfall of (1000 – 1500) mm during the growing season or near the major rivers.
6. WASTE CHARACTERISTICS The main air emissions from sugar processing and refining result primarily from the combustion of bagasse (the fiber residue of sugar cane), fuel oil, or coal. Other air emission sources include juice fermentation units, evaporators, and sulfitation units. Approximately 5.5 kilograms of fly ash per metric ton (kg/t) of cane processed (or 4,500 mg/m3 of fly ash) are present in the flue gases from the combustion of bagasse. Sugar manufacturing effluents typically have biochemical oxygen demand (BOD) of 1,700 – 6,600 milligrams per liter (mg/l) in untreated effluent from cane processing and 4,000 – 7,000 mg/l from beet processing; chemical oxygen demand (COD) of 2,300 – 8,000 mg/l from cane processing and up to 10,000 mg/l from beet processing; total suspended solids of up to 5,000 mg/l; and high ammonium content. The wastewater may contain pathogens from contaminated materials or production processes. A sugar mill often generates odor and dust, which need to be controlled. Most of the solid wastes can be processed into other products and by-products. In some cases, pesticides may be present in the sugar cane rinse liquids.
6.1 Pollution Prevention and Control:
Good pollution prevention practices in sugar manu facturing focus on the following main areas:
Reduce product losses to less than 10% by better production control. Perform sugar auditing.
Discourage spraying of molasses on the ground for disposal.
Minimize storage time for juice and other intermediate products to reduce product losses and discharge of product into the wastewater stream.
Give preference to less polluting clarification processes such as those using betonies instead of sulfite for the manufacture of white sugar.
Collect waste product for use in other industries — for example, bagasse for use in paper mills and as fuel. Cogeneration systems for large sugar mills generate electricity for sale. Beet chips can be used as animal feed.
Optimize the use of water and cleaning chemicals. Procure cane washed in the field. Prefer the use of dry cleaning methods.
Recirculate cooling waters.
Continuous sampling and measurement of key production parameters allow production losses to be identified and reduced, thus reducing the waste load.
Fermentation processes and juice handling are the main sources of leakage.
Odor problems can usually be prevented with good hygiene and storage practices.
6.2 Target Pollution Loads:
Since the pollutants generated by the industry are largely losses in production, improvements in production efficiency are recommended to reduce pollutant loads. Approximately 90% of the saccharose should be accounted for, and 85% of the sucrose can be recovered. Recirculation of water should be maximized. Wastewater loads can be reduced to at least 1.3 m3/t of cane processed, and plant operators should aim at rates of 0.9 m3/t or less through recirculation of wastewater. Wastewater loads from beet processing should be less than 4m3/t of sugar produced or 0.75 m3/t of beet processed, with a target of 0.3 to 0.6 m3/t of beet processed.
6.3 Treatment Technologies:
Pretreatment of effluents consists of screening and aeration, normally followed by biological treatment. If space is available, land treatment or pond systems are potential treatment methods. Other possible biological treatment systems include activated sludge and anaerobic systems, which can achieve a reduction in the BOD level of over 95%. Odor control by ventilation and sanitation may be required for fermentation and juice-processing areas. Biofilters may be used for controlling odor. Cyclones, scrubbers, and electrostatic precipitators are used for du st control.
7. CONCLUSION
India has been known as the original home of sugar and sugarcane. It is the world‘s second largest sugar producer and consumer. The Indian sugar industry is a key driver of rural development, supporting India's economic growth. The industry is inherently inclusive supporting over millions of farmers and their families, along with workers and entrepreneurs of hundreds of mills, apart from a host of wholesalers and distributors spread across the country.
By products, productivity improvements combined with price risk management tools and international trade Indian sugar industry can aim to improve profitability and reduce cyclicality.
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