Ethyl Alcohol: Ethyl Alcohol Shakti Bhardwaj PowerPoint Presentation: WHAT IS EHYL ALCOHOL? Ethanol is a volatile , flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs . Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers , as a solvent , and as a fuel . In common usage, it is often referred to simply as alcohol or spirits . USES OF ETHYL ALCOHOL: USES OF ETHYL ALCOHOL As a fuel for lamp and stoves. As a substitute of petrol in internal combustion engines. As a solvent for drugs, tinctures, oil, perfumes ink, dyes varnishes etc. As a beverage. Preservative for biological specimens. As anti-freeze for automobile radiators. As a low freezing (fp-11.70) and mobile fluid in scientific apparatus such as thermometers and spirit levels. As a raw material for a large number of organic compounds including ethylene, ether, acetic acid, idoform , chloroform, chloral etc. For manufacturing of terylene and polythene. RAW MATERIALS: RAW MATERIALS PowerPoint Presentation: SUGAR CROP Sugar cane The fermentable carbohydrates, from sugar cane may be directly utilized in the form of cane juice or in conjunction with a sugar factory from a black strap molasses. FRUIT CROP Fruit with high fructose and sucrose content are grapes, peaches, apricots, peas, pineapples and apple. Typically, fruit crops such as grapes are used as the feedstock in wine production . These crops are not likely to be used as feedstock for production of fuel-grade ethanol because of their high market value for direct human consumption STARCHES A variety of starches can be used for ethanol production by fermentation. Corn is the most viable feed stock for the manufacture of ethanol in United States. Keeping all facts in mind, black strap molasses are economically feasible and best result oriented in alcohol industries. So, widely used in INDIA. MOLASSES: MOLASSES It is a waste product of sugar industry of which further extraction of sugar is uneconomical. Hence molasses is a solution of sugar, organic matter and inorganic matter in water. Molasses is generally used because it is rich in all salts except nitrogen. General composition of cane molasses varies with - variety of maturity of cane -climate and soil condition. -processing condition in the sugar factory PHYSICAL CHARACTERISTICS Molasses is a dark reddish colored jelly like viscous material. pH -- 6.8 to 8.5. The high osmotic pressure of molasses protects it from microbial spoilage, it can be easily transported by barge and tankers etc. Molasses can be pumped easily. GRADES OF MOLASSES a) First grade Molasses: It contains more than 50%TRS. b) Second grade Molasses: It contains 40%to 50% TRS. c) Third grade Molasses: It contains less than 40% TRS. Various manufacturing process : Various manufacturing process Various manufacturing process of ethanol are: Synthetic process (from ethylene) As a byproduct from various industrial operation. By fermentation of sugars, grains, fruits, cellulose etc. PROCESS SELECTION Synthetic ethanol is dominating the market because of its economy, but crude petrochemical supply is exhaustible. ethylene feed stock can be more effectively use for other chemicals. Agriculture based raw materials which are sugars, starches, cellulose are renewable. So, they possess the capacity to supply ethanol for a very long time. Fermentation process is a cheaper process. 1 Kg of ethanol production requires 2 kg sugar or 3.3 kg corn or 4 Kg molasses or only 6 kg ethylene. But except ethylene, only molasses have lower prices. Describing fermentation: Describing fermentation The action of specific micro-organism on a complex organic substrate to degrade it to produce the desired chemical compound is termed as Fermentation. THE PRINCIPAL MEDIA Molasses Urea (NH2CONH2): Urea is added to fulfill the requirement of nitrogen for good fermentation. Sulphuric Acid: Sulphuric acid is added to bring down the pH value to an optimum level (4.2 -4.8). pH plays a vital role in good fermentation. Yeast: The most popular yeast strain used is Saccharomyces Cerevisiae it is able to produce and tolerate high concentrations of ethyl alcohol. It also possess uniform and stable characteristics. Di Amonium Phosphate Phosphoric Acid Antibiotic: To prevent the contamination (growth of other bacteria) an anti-biotic Benzyl Penicillin is used. PowerPoint Presentation: Fermentation conditions Temperature during fermentation 28-34 Centigrate Settling gravity of yeast vessels 1.045 Settling pH of yeast vessels 4.5 – 4.9 Settling gravity of pre- fermenters 1.05 Final gravity after complete fermentation 1.031.00 Duration of fermentation 24 hours % alcohol after completion 5-8% Reactions in the fermentation C 12 H 22 O 11 + H 2 O =============== C 6 H 12 O 6 + C 6 H 12 O 6 S ugar I nvertase Glucose Fructose C 6 H 12 O 6 ========= 2C 2 H 5 OH + CO 2 + Heat Zymase ethyl alcohol As shown in the chemical reaction it is an exothermic reaction so cooling is required, Description of Fermentation Unit : Description of Fermentation Unit Specific gravity of molasses in storage tanks is around 1.4. It is brought into fermentation section through pumps and it is diluted to specific gravity of around 1.05 as per the requirement. Molasses is sterilized in preparatory tanks by air. Contamination of pure cultures used in fermenters is avoided by heat sterilization of air. This is accomplished by compressing it at high temperature and removing all the dust by passing through Potassium Permanganate. Now water is added to the molasses to bring down its specific gravity up to 1.05 now yeast ( S.cerevisiae ) is added. To provide food for the yeast and proper functioning of the process Urea and Orthophosphoric acid is mixed. To maintain its pH 4.5 – 5 Sulphuric acid is added. It is kept in preparatory for 5 – 8 hours. Next Benzene Penicillin is added so that only yeast remains and other harmful bacteria are killed. Now it is sent to pre- fermenter molasses of specific gravity around 1.10 is mixed in it. It is kept here for around 7 – 8 hours. Then it is processed to fermentation vat. PowerPoint Presentation: Anti-foam agent is added to prevent vigorous overflowing. It is then closed and kept for 24 hours. Carbon dioxide produced as by product is sent to cooling section and the fermented molasses is sent to distillation column as the feed. The fermented liquid is technically called wash. Requirements for batch operation For the fermentation we require standing cylindrical fermenter designed to have larger height than the diameter of vessel, having following characteristics: 1. Made from stainless steel because corrosion problem and necessity for cleanliness and sterility. 2. Fitted with manholes at the bottom and top of the fermenter . 3. Inspection glass above the bottom manhole. 4. Thermometer and CO2 collection tube at the top. 5. Cooling coil for the hot temperature control during fermentation. 6. By pass valve in the air system allowing diversion of the air so that the foaming is not excessive. 7. Anti-foam is added when reached up to capacitive probe. Merits of fermentation process over the chemical synthesis: : Merits of fermentation process over the chemical synthesis: Cheaper raw material may be used. Desired changes may be brought about in one step, which would be otherwise produced by a lengthy process. Fermentation is only process for synthesizing some complex compounds. It works under less drastic conditions compared to chemical process. Unwanted compound may be removed from the products. Material balance: Material balance For 100% conversion of sucrose to ethanol, according to stochiometry of reaction we have 342 Kg of Sucrose gives Ethanol = 4*46 Kg 184 Kg of Ethanol Assume 95% of total sucrose is converted into Ethanol So, 342 Kg of Sucrose will give Ethanol =184*0.95 Kg 174.8 Kg of Ethanol As molasses contains 52% fermentable sugar in form of sucrose So molasses in 342 Kg sucrose is 342/0.52 = 657.69 Kg Assuming 10% less alcohol is produced due to pipe losses, so total molasses required for 1 litre of ethyl alcohol is 3.26 Kg. 174.861kg of alcohol requires 657.69 kg of molasses 1 kg of alcohol requires 3.76 kg of molasses Due to 10% loses 1kg of alcohol requires molasses= (3.76 + 3.76*0.1)kg = 4.136kg PowerPoint Presentation: 1l of ethyl alcohol requires=4.136*0.789 kg of molasses = 3.26kg of molasses Basis:- Production of 20,000 kg/day (95% by wt.) Yeast culture needed = 5% by wt. of mash Concentration of yeast cells in culture = 12.5 gms /lit. BALANCE OVER MASH PREPARATION SECTION:- As we know, 1 lt. of Ethanol requires 3.26 Kg of Molasses 0.789 kg of Ethanol requires 3.26 Kg of Molasses. 1 kg of Ethanol requires molasses = 3.26/ 0.789 = 4.131 Kg 200000 kg of Ethanol requires molasses= 4.13* 20000 So molasses required = 82620.24 kg/day Water added to the molasses = 4 parts/ parts of molasses. So, water added = 4 x 82620.24 = 330480.99 kg/day PowerPoint Presentation: Mash produced = 330480.99+ 82620.24= 413100 kg/day As molasses contains 52% fermentable sugar in form of sucrose. So, sugar in molasses = 0.52 x 82620.24 = 42962.4 kg sugar/day According to the stochiometry , for 95% conversion of sucrose to ethanol, 342 Kg sucrose gives 174.80 Kg of pure ethanol 1kg of ethanol require 0.511 of sucrose = 0.511* 42962.84 So pure ethanol produced = 21953.78kg pure ethanol BALANCE OVER FERMENTER- Feed to fermenter includes: Mash = 413100 kg/day Yeast culture = 0.05 * 413100 kg/day = 20655.06kg/day Cell Concentration = 12.5 gms /lit So cells present = (12.5 x 10 -3 ) x 413100 kg/day = 5163.75kg/day cells Nutrient Present :- Ammonium Sulfate = 1113 kg/day PowerPoint Presentation: OUTPUT OF FERMENTER INCLUDES :- Ethyl Alcohol = 21953.78kg pure ethanol 2. CO 2 Gas 3. Residue with Biomass (it also have some quantity of sucrose) 4. Waste Water (H 2 O) Unconverted Sugar Now water required for reaction to produce pure alcohol is Moles of sucrose = Moles of Water (18/342) x 42962.4 =2261.6kg/day i.e. water added = 2261.6kg/day Initially total water added = 330480- 2261.6= 328218.821kg/day As we are using 890 kg of 80% H 2 SO 4 solution, it also contains 178 kg of water. So total water coming outside fermenter = 328218.821+ 178 = 328396.39 kg/day This wastewater can be reused in various regions after proper treatment only. PowerPoint Presentation: 2. From reaction stochiometry , Moles of CO 2 = moles of ethanol produced Wt. = (21953.78) /46 = 477.25 kmoles /day So CO 2 produced = 477.25x 44=20999.264kg of CO 2 /day BIOMASS PRODUCED:- The material balance over the fermenter with respect to yeast bacterial mass is :- [Change within the vessels] = [Increase due to feed] + [Increase due to growth] – [Decrease due to loss in effluents] – [decrease due to death] It can be given as dx / ds = 0.5gm/gm = x-x 0 /s 0 -s = y x /s & [ dx / ds = k] Value of k for ethanol system is 0.5, value taken from book “ Wasteless Chemical Processing” Page No. 134 by V.V. Kafarov Where x & x 0 = dry cell mass finally and initially S & s 0 = Substate mass finally and initially PowerPoint Presentation: We have x 0 = 5163.76 kg S 0 = 42962.4 kg of sugar S = final wt. of substrate left moles of ethanol = 21953.78/46.07 = 477.45 Kmoles /day from stochiometry of reaction, moles of sucrose converted = 477.45/4 = 119.36 kmoles initial no. of moles of sucrose = 42962.4/342 = 125.62 kmoles moles unconverted = 125.62 - 119.36 = 6.306 kmoles Kg. of substrate at the end = 6.306 x 342 S = 2156.652 kg/day Now, x-x 0 /s 0 -s = 0.5 therefore by putting values x = 25566.652 kg of cells Along with the cell goes out about 50% water so water present = 25566.652x 0.5 = 12783.312 kg water PowerPoint Presentation: Therefore weight of biomass = 12783.312+ 25566.652 = 38349.9368 kg So, we obtained C2H5OH = 21953.7864 kg Water = 328396.39 – 12783.312 = 315613.652kg Unconverted sugar + fusel oil = 2156.652 kg CALCULATION FOR PERCENTAGE OF ALCOHOL IN THE WHOLE LIQUID INSIDE THE FERMENTER :- Total weight of products obtained in fermenter spent biomass = Spent Wash So, 21953.78+315613.509+2156.652–38349.98= 301374.0114 kg Percentage of alcohol in spent wash = (21953.7864 / 301374.0114) x 100 = 7.3 % Spent wash is liquid in fermenter , which have to be spent to column. PowerPoint Presentation: MATERIAL BALANCE OVER DISTILLATION COLUMN :- Input = Pure alcohol + water + impurities = 301374.0114 kg/day From balance on distillation column, we get, F = D + R 301374.0114= 20000 + R R = 281374.011 F.x f = D.x d + R.x r Where x f , x d , x r are weight fractions in feed, product and residue of ethyl alcohol 301374.0114 * 0.073 = 20000* 0.95 + 281374.01 * x r x f = 7.3 % x d = 95 % (desired) x r = 1.06% PowerPoint Presentation: CONCLUSION It is concluded from our project work that ethanol production from molasses, is cost feasible. In this project work we had used continuous process instead of batch process by the help of little modification in the earlier process. Cost estimation for this process is also feasible.