Fuel ethanol overview - Ethanol is a liquid transportation fuel made from renewable resources or plant biomasses such as agricultural wastes, corn, grain, grasses, sugar cane, straw, wood based waste such as newsprint, woodchips, and manufacturing waste materials.  Ethanol is a clean burning fuel that lowers overall Green House Gas Emissions (as the biomass absorbs Carbon Dioxide as it grows), contains a high percentage of oxygen (35%) producing more complete fuel combustion, can be blended with petroleum and integrates into existing fuel delivery systems and provides energy security by reducing our reliance on fossil fuels. New Flexible Fuel Vehicles currently available, operate on E85 ethanol based fuels with a content of 85% ethanol and 15 % petroleum. For frequently asked questions on ethanol, click here.  

How is ethanol made?
Conventional ethanol production facilities like the methods used in Brazil, the world’s leading ethanol adopting country, utilizing high sugar content feedstock such as sugar cane.  Brazil produced 14 billion liters in 2004 replacing 40 % of its gasoline demand and in April 2006 they were completely independent of Middle East oil imports.   Most news cars sold in Brazil today (manufactured by North American auto makers) are Flexible fuel vehicles that operate on ethanol, gasoline or any blend of the two.  Currently all fuel sold in Brazil has a minimum percentage of 25% ethanol.

The majority of ethanol produced in North America is produced from corn, but feed stocks such as switchgrass produce higher yields.  In 2005, the United States produced 15 billion liters, although The Energy Policy Act mandates ethanol production must increase to 28 billion liters by 2012. In the US, ethanol is commonly blended with gasoline up to 10%, referred to as E10 and sold primarily in the Midwest States. General Motors plans to produce 400,000 flexible fuel vehicles annually and state that they have 2 million cars on the road in all 50 states that are capable of running E85 without any modification.

Ethanol can be manufactured using a dry mill or wet mill process, the majority of ethanol produced in the United States uses the dry mill method.  In dry mill the starch portion of the corn is fermented into sugar then distilled into alcohol.  The distinct difference with the two processes is the initial treatment of the biomass.


Steps in the dry mill process

1. Milling - In the dry milling process the feedstock or biomass is ground through a hammer producing a fine powdered meal. 
2. Liquefaction - The meal is then mixed with water and alpha-amylase, and then passed through cookers where the starch is liquefied. Heat is 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) are used. High temperatures reduce bacteria levels in the mash.
3. Saccharification - The mash is then cooled and the secondary enzyme (gluco-amylase) is added to convert the liquefied starch to fermentable sugars (dextrose). 
4. Fermentation - Yeast is added to the mash to ferment the sugars to ethanol and carbon dioxide. Using a continuous process, the fermenting mash is allowed to flow through several fermenters until it is fully fermented and leaves the final tank. In a batch process, the mash stays in one fermenter for about 48 hours before the distillation process is started. 
5. Distillation - The fermented mash, now called beer, contains about 10% alcohol plus all the non-fermentable solids from the corn and yeast cells. The mash is pumped to the continuous flow, multi-column distillation system where the alcohol is removed from the solids and the water. The alcohol leaves the top of the final column at about 96% strength, and the residue mash, called stillage, is transferred from the base of the column to the co-product processing area.  
6. Dehydration - The alcohol from the top of the column passes 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 ethanol (pure, without water) and is approximately 200 proof.  
7. Denaturing - Ethanol that will be used for fuel must be denatured, or made unfit for human consumption, with a small amount of gasoline (2-5%). This is done at the ethanol plant. 

There are two main co-products created in the production of ethanol: distiller’s grain and carbon dioxide.  Distiller’s grain, used wet or dry, is a highly nutritious livestock feed. Carbon dioxide is given off in great quantities during fermentation and many ethanol plants collect, compress, and sell it for use in other industries.  In addition, the fuel cell industry has developed re-formulators that use ethanol as a source of hydrogen.   

Ethanol can be produced from a variety of feedstocks, such as sugar cane, miscanthus, sugar beet, sorghum, switchgrass, barley, hemp, kenaf, potatoes, sweet potatoes, cassava, sunflower, fruit, molasses, whey or skim milk, corn, corn cobs, grain, wheat, wood, paper, straw, cotton, grain sorghum, barley, other biomass, well as many types of cellulose waste. 

The next development in the production of ethanol is to look at more efficient methods of producing ethanol and more production crops.made- Ethanol is currently the most popular alternative liquid transportation fuel made from renewable resources such as agricultural wastes, corn, grain, grasses, sugar cane, straw, wood and any cellulosic materials. 

Biomaxx Systems plans to develop a new innovative biotechnology process to produce ethanol from any cellulose based material with distinct advantages over conventional methods.