Possible Sources:

First Generation bioethanol is based upon the starch crops. Possible crops include corn (maize), sugar cane, sugar, beets, palm oil, sorghum, soy beans, and wheat. (2)

Biomass source may alter production process however, general steps include:

1. Milling (Cane crushing and juice extraction)

2. Dilution

3. Hydrolysis for starch and woody biomass

4. Fermentation with yeast and enzymes

5. CO2 storage and ethanol recapture

6. Evaporation

7. Distillation

8. Waste water treatment

9. Fuel Storage

Production of Bioethanol from Sugar Cane:

The process of milling is when the sugar cane is cut into regular pieces. During the process of milling the sugar cane is washed, chopped, and shredded using revolving knives. Once shredded, the cane is fed through mill combinations that crush extract cane juice. The cane juice is filtered and pasteurized as well as heat treated to kill micro-bacterial impurities. The liquid is then put through evaporation and cooling for crystallization. This produces crystals and molasses, the two are separated through the process of centrifugation.  Further pasteurization and fermentation process take place for up to 10-12 hours until finally distilled to a higher concentration of alcohol. (1)

Production of Bioethanol from Cereal Crops:

The process for cereal crops is similar to that of sugar cane except with the additional process of hydrolysis to break down the polymers to monomers which can then be broken down into simple C6 sugars. During milling, the starch is released and diluted in water to adjust the volume of sugar in the mixtrure. The mixture is then cooked with yeast all the soluable starches dissolve in the water. Through acid hydrolysis or enzymes the starch is converted into sugars. The fermented liquid is known as “beer”. Through various evaporation  and distillation processes the liquid is raised to fuel grade ethanol. (1)

(Composed by Matthew Schmitt, Edited by Tien Tran)

References:

“Bioethanol Fact Sheet.” Www.sts-technology.com/. STS- Technology, 2015. Web. 6 May 2015.

“Bioethanol Production and Use.” Www.erec.org. Supported by the European Commission – FP6, 2 July 2007. Web. 21 Apr. 2015. (1)

Simblotti, Giorgio. “Biofuel Production.” www.iea.org. IEA,org/publications, 1 Jan. 2007. Web. 20 Apr. 2015. (2)