Production of Fuel Ethanol from Cereals

Anhydrous ethanol has been used as a fuel since the early 1900s. During the past 10 years, the interest in and use of fuel ethanol has dramatically increased because it is a renewable fuel, the escalation of petroleum prices, and the positive proven environmental benefits compared to combustion of fossil fuels. Brazil and the United States are the two main producers of fuel ethanol the former produces most of the 

The simplest way to produce ethanol is from sweet juices extracted from sugarcane, sugar beet, or sweet sorghum because the juice is directly fermented and then distilled to obtain fuel-grade ethanol. The disadvantages of this process are the relatively low conversion rates (70 L/ton), the relatively low shelf life of the cut stalks, and the seasonal harvesting that impedes the utilization of the biorefinery throughout the whole year. 

Continuous Distillers and Azeotropic Distillation or Use of Molecular Sieve 

FIGURE 14.8 Flowchart of the commercial production of fuel ethanol from cereal grains. 

From the environmental viewpoint, ethanol burns more cleanly because it produces less carbon monoxide, nitrogen oxides, sulfur oxides, suspended particles, and other contaminating hydrocarbons. Another important advantage of ethanol is that when it is accidentally spilled, the ecosystem is not much affected, because it decomposes in about a week. 

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