Ethanol Fuel Essay

Submitted By MounikReddy1
Words: 1333
Pages: 6

Renewable Energy
The Ethanol Production Process
Flow Meters and Controls

Dry Mill

Direct Reading Flowmeters For Liquids and Gases

Ethanol- How it s made....
There are three main uses for ethanol (industrial, beverage and fuel) and production varies for each industry. Ethanol production in the US is primarily used for fuel consumption using a dry mill process. It takes 1 bushel (56 lbs.) of corn to produce an estimated 2.5 to 3.0 gallon of ethanol. Now more then ever US consumption of ethanol will increase dramatically over the next few years from 2 billion to over 7 billion gallons per year. Our goal is to eliminate our dependence on foreign oil. The following steps go into the production of ethanol. • • Milling: The corn will first pass through hammer mills, which grind it into fine powder called meal. Liquefaction: The meal will then be mixed with water and alpha-amylase, and will pass through cookers where the starch is liquefied. Heat will be applied at this stage to enable liquefaction. Cookers with a high temperature stage (120-150 degrees Celsius) and a lower temperature holding period (95 degrees Celsius) will be used. These high temperatures reduce bacteria levels in the mash. Saccharification: The mash from the cookers will then be cooled and the secondary enzymes (gluco-amylase) will be added to convert the liquefied starch to fermentable sugar (dextrose), a process called saccharification. Fermentation: Yeast will then be added to the mash to ferment the sugar to ethanol and carbon dioxide. Using a continuous process, the fermenting mash will be allowed to flow, or cascade, through several fermenters until the mash is fully fermented and then leaves the final tank. Distillation: The fermented mash, now called "beer", will contain about 10% alcohol, as well as all the non-fermentable solids from corn and the yeast cells. The mash will then be pumped to the continuous flow, multi-column distillation system where the alcohol will be removed from the solids and the water. The alcohol will leave the top of the final column at about 96% strength, and the residue mash, called stillage, will be transferred from the base of the column to the co-product processing area. Dehydration: The alcohol from the top column will then be passing through a dehydration system where the remaining water will be removed. Most ethanol plants use a molecular sieve to capture the last bit of water in the ethanol. The alcohol product at this stage is called anhydrous (pure, without water) ethanol and is approximately 200 proof. Denaturing: Ethanol that will be used for fuel is then denatured with a small amount (25%) of some product, like gasoline, to make it unfit for human consumption. Co-Products: There are two main co-products created in the production of ethanol: carbon dioxide and distillers grain. Carbon dioxide is given off in great quantities during the fermentation and many ethanol plants collect that carbon dioxide, clean it of any residual alcohol, compress it and sell it for use to carbonated beverages or in the flash freezing of meats. Distiller grains, wet and dried, are high in protein and other nutrients and are a highly valued livestock feed ingredient. Syrup is another byproduct containing some of the solids that can be sold. Ethanol production is a no-waste process that adds value to the corn by converting it into more valuable products.

• •

Taken from the American Coalition for Ethanol

Ethanol Flow Chart
Grain Receiving Corn Meal Mash Preparation Corn Mash

Dry Milling

22,000 bushel s / day

Ammonia Enzymes

Carbon Dioxide Beer Distillation Whole Stillage Centrifugation Thin Stillage Evaporation Syrup Wet Grains Dryer DDGS DDGS Storage 180 Tons/ Day DDGS Dehydration 200 Proof Ethanol Product Storage Fuel Ethanol Rail, Truck Nationwide

Rail, Truck Nationwide

• • • 1 Bushel = 56 lbs. of Corn 3 Gallons of Ethanol / Bushel Capacity 42,000,000.00