ABSTRACT
As a monohydric C2 alcohol, ethanol or ethyl alcohol is one of the simplest alcohols and has long been consumed throughout the world in human history. The principal use of ethanol has always been in the preparation of alcoholic beverages till very recently. Commonly, ethanol has been called simply “alcohol” and “spirits.” Ethanol is readily produced by fermentation of simple sugars that are obtained from sugar
11.1 Introduction .................................................................................................. 359 11.2 Corn Ethanol as Oxygenated Fuel ................................................................ 365
11.2.1 Industrial Signicances of Grain Ethanol ........................................ 365 11.2.2 Clean Air Act Amendments of 1990 ................................................366 11.2.3 Energy Independence and Security Act of 2007 .............................. 367 11.2.4 Net Energy Balance of Corn Ethanol Production............................. 368 11.2.5 Food versus Fuel ............................................................................... 369 11.2.6 Process Technologies of Corn Ethanol Production .......................... 370
11.2.6.1 Dry Mill Process versus Wet Mill Process ........................ 370 11.2.6.2 Energy Generation and Supply for Ethanol Plants ............ 370 11.2.6.3 Feedstocks and Organisms for Ethanol Fermentation ....... 371 11.2.6.4 Starch Hydrolysis ............................................................... 371 11.2.6.5 Yeast Fermentation ............................................................ 372 11.2.6.6 Ethanol Purication and Product Separation..................... 373 11.2.6.7 By-Products and Coproducts ............................................. 373 11.2.6.8 Potential Environmental Issues of Liquid Efuents .......... 374
11.3 Chemistry of Ethanol Fermentation ............................................................. 374 11.3.1 Sugar Content of Biological Materials ............................................. 374 11.3.2 Conversion of Sugars to Ethanol ...................................................... 375
11.4 Corn-to-Ethanol Process Technology ........................................................... 377 11.4.1 Wet Milling Corn Ethanol Technology ............................................ 377 11.4.2 Dry Milling Corn Ethanol Process ................................................... 381 11.4.3 Industrial Cleaning of Ethanol Plant ................................................384
