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Bioethanol technology.Bioethanol technologypptx
- 1. Bioethanol production Dr. Shazia Rehman
- 2. Bioethanol Production • Bioethanol Production • Ethanol, also known as “ethyl alcohol” or “grade alcohol”, • Its molecular formula is C2H6O, Bioethanol • Ethanol or ethyl alcohol produced by hydrolysis and then fermentation processes from biomass is called as bioethanol.
- 3. Conti…. • WHAT ARE THE RAW MATERIALS FOR BIOETHANOL? There are in general three groups of raw material: 1). Sugar : Beet, Sugar Cane, Sweet Sorghum and Fruits. 2). Starchy Material such as corn, wheat, rice, potatoes, cassava, sweet potatoes etc. 3). Cellulose materials like wood, used paper, crop residues etc. Ethanol obtained from sugars and starch is referred to as the first generation bioethanol, while lignocellulosic biomass and algae produce second and third generation bioethanol, respectively.
- 4. STEPS FOR ETHANOL PRODUCTION • STEPS FOR ETHANOL PRODUCTION Fermentation Process Distillation Process Dehydration Process
- 5. MICROORGANISMS for BIOETHANOL PRODUCTION
- 7. Sugar-to-Ethanol Process Sugar-to-Ethanol Process The simplest way to produce ethanol is the sugar-to-ethanol production. Biomass is used that contains six-carbon sugars which can be fermented directly to ethanol. Examples for typical sugary feedstock types are sugar cane and sugar beets which contain substantial amounts of sugar. The major advantages of sugar crops as ethanol feedstocks are high sugar yield and low conversion costs, while the seasonal availability of these crops is the main limiting factor
- 8. Bioethanol from sugarcane • Sugarcane (Saccharum officinarum) is a C4 plant having high capability to convert solar radiation into biomass • The stalk juice of sugarcane and by-product of sugar refineries (molasses) has been used as promising feedstocks for bioethanol production over many years. • Sugar can be directly extracted from sugarcane • Sugarcane juice is the main feedstock in Brazil that produces about 79% of its bioethanol from this feedstock, whereas molasses is the major ethanol feedstock in India
- 9. Steps • Harvesting The first step is sugarcane harvesting. Much of the harvesting is done with manual labor, particularly in many tropical regions. Some harvesting is done mechanically. • Extraction juice is extracted from the sugar crops by crushing stalks (sugarcane and sweet sorghum) or root (sugar beet) in a specialized roller. Lime (calcium hydroxide) is then added to precipitate the fiber and sludge, and mixture is then filtered. The filtrate sugar solution is evaporated to condense it to a sugar level ranged between 14% and 18%
- 10. Conti…. Fermentation The next step is fermentation process Fermentation of sucrose is performed using commercial yeast such as Saccharomyces ceveresiae. Chemical reaction is composed of enzymatic hydrolysis of sucrose followed by fermentation of simple sugars
- 11. Conti… First, invertase enzyme in the yeast catalyzes the hydrolysis of sucrose to convert it into glucose and fructose. Second, zymase, another enzyme also present in the yeast, converts the glucose and the fructose into ethanol.
- 12. Conti… The carbon dioxide formed is allowed to escape, but air is not allowed to enter. The fermentation is complete in 3 days. The carbon dioxide obtained as byproduct is recovered and can be sold. Distillation The fermented liquor contains 9-10% of ethanol and is called wash or wort. It is distilled to remove water and other impurities. Dehydration A dehydration process is used to obtain anhydrous ethanol. The distillate contains about 90% alcohol and the residue left in the still is used as cattle feed
- 15. Bioethanol production using starch Bioethanol production using starch based feedstocks Grains (corn, wheat or barley) mainly provide starch. For example, corn contains 60–70% starch. This type of feedstock is the most utilized for ethanol production in North America and Europe. In starch, polymers of glucose are broken into glucose through a hydrolytic reaction catalyzed by gluco-amylase enzyme. The resulting sugar is known as dextrose or D-glucose that is an isomer of glucose. The enzymatic hydrolysis is then followed by fermentation, distillation and dehydration to yield anhydrous ethanol
- 17. Methods There are two distinct methods for processing corn, wet milling dry milling Dry mills are usually smaller in size (capacity) and are built primarily to produce only ethanol. Wet mill facilities are called corn refineries, that also produce a list of high-valued co-products such as high-fructose corn syrup (HFCS), dextrose, and glucose syrup Both wet and dry milling operations convert corn into ethanol
- 18. Corn dry-milling process • Corn dry-milling process • Corn dry-milling process is carried out in five steps viz: (i) biomass handling (milling) (ii) liquefaction (iii) hydrolysis (saccharification) (iv) fermentation (v) distillation and recovery
- 19. Conti…. Milling Dry-grind method involves preparation of slurry by mixing corn flour with water which is then heated at 85 ᵒC. Liquefaction Slurry is then liquefied with a thermostable α-amylase to breakdown the starch molecules into dextrin and other smaller molecules. Saccharification and fermentation The dextrins are further converted to glucose using glucoamylase (GA) enzymes during saccharification process, which is fermented to ethanol by yeast.
- 20. Conti… Saccharification and fermentation are performed in single step in the same reactor by process known as simultaneous saccharification and fermentation (SSF). Distillation and recovery After fermentation, the resulting beer is transferred to distillation columns where ethanol is separated from the remaining stillage Remaining stillage, is then separated into thin stillage and solid fraction. One portion of the thin stillage is recycled as backset in the process to decrease water consumption and another portion is condensed into thick stillage (syrup). The solid portion is mixed with thick stillage to obtain a final co-product, DDGS, which is sold and used as animal feed
- 23. Wet milling process of corn 1. Steeping: soak corn for 24- 48 hours. 2. Coarse milling: separate the germ from the kernel. 3. Fine milling: separate fiber from endosperm 4. Separation: separate starch from gluten. 5. Hydrolysis 6. Fermentation 7. Distillation 8. Dehydration 9. Denature 10. Storage