Ethanol

Ethanol, also known as grain alcohol, is an alternative fuel produced by fermenting and distilling starch crops that have been converted into simple sugars. Feedstocks for this fuel include corn, barley, and wheat. Brazil has pioneered an ethanol derived from sugar cane. Ethanol also can be produced from "cellulosic biomass" such as trees, grasses, and farm waste products. Fuel derived from cellulose is commonly called cellulosic ethanol.

In 2005, the United States produced over 4 billion gallons of ethanol. One hundred and five ethanol production facilities exist in the United States today; forty-six more currently are under construction. Ethanol use has many advantages. The product is commonly used to increase octane and improve the emissions quality of gasoline. Environmental Protection Agency rules allow it to be blended into gasoline without notification in proportions up to 10% ethanol, called E-10. Often, it is blended with gasoline in higher proportions to create E-85 motor fuel for use in spark-ignited engines. E-85 is a mix of 15% gasoline and 85% ethanol. Vehicles that have been designed to run on E-85, and those that can run on any mixture of gasoline and ethanol, are called flexible fuel vehicles (FFVs). For a list of FFVs available for sale and under development, visit Discover Alternatives.

Visual source: http://www.bigriverresources.com/images/process.jpg

Ethanol production: Ethanol can be made in either a dry mill or a wet mill process. In the dry mill process, corn is ground into a fine power called meal, then mixed with water and catalysts that liquefy the mixture and break it down into sugars. Next, yeast is added to convert the sugars into ethanol and carbon dioxide. Then, the ethanol is distilled out and the surplus water removed from the alcohol. Finally, the ethanol is denatured, or mixed with a small amount of gasoline to make it undrinkable. The two co-products, dried distillers grain and carbon dioxide, are sold to other industries. Most U.S. ethanol producers use the dry mill process. Wet milling is the process of separating the corn kernel into starch, protein, germ and fiber prior to fermentation. This process produces high frutose corn syrup as an additional co-product.

Sources:

• National Ethanol Vehicle Coalition
• Department of Energy’s Alternative Fuels Data Center
• American Coalition for Ethanol
• Ethanol Fact versus Fiction report
• Renewable Fuels Association