Ethanol is made in large quantities by using a
fermentation/distillation process not unlike how certain drinking
alcohols (like whiskey) are distilled and fermented. Basically,
feedstock (corn, wheat, barley, etc.) is first crushed into a fine
powder called meal. In the US, corn is the biggest source of distilled
ethanol. Next, the mash is mixed with water and the mixture is cooked
over heat in order to help break down the sugars. Yeast is added and
the sugars are converted into ethanol through a multi-step
multi-container fermentation process. After fermenting, this fermented
mash, also called beer, only contains about 10% alcohol and is put
through distillers which evaporate the alcohol so it can be separated.
This distilled ethanol is almost pure at around 96% and passes through
a dehydration system to remove the last of the water producing pure
ethanol. In order to control the sale and use of this pure ethanol, it
is then denatured (doped with a 2%-5% of gasoline) to make it unfit
for human consumption.
As for the byproducts, this is a relatively clean process. The only
byproducts are distiller's grain (the solids left over from the
fermentation process) and carbon dioxide, both of which can be used
further. Distiller's grain can be used to feed livestock as only the
starch is removed from the corn (or other feed) leaving the protean,
fat, minerals, and vitamins intact. From the ethanol.org website, "A
bushel of corn weighs 56 pounds and will produce at least 2.7 gallons
of ethanol and 17 pounds of distillers grain." Carbon dioxide which is
produced during the fermentation process and can be bottled and sold
to other industries (soda making, chemical plants, etc.). The only
real consumables is the energy used to heat up the mash and distill it
as well as the water and yeast necessary to make the fermentation
possible.
More technical information (including details of each individual step)
can be found on the American Coalition for Ethanol (ACE) website
linked below.
Additional Links:
ACE website:
http://www.ethanol.org/
How ethanol is produced (step-by-step):
http://www.ethanol.org/howethanol.html
Corn to whiskey fermentation chemistry:
http://www.thewhiskystore.de/experts/starch.htm
Thank you for your question, and it was my pleasure to answer it for you.
skermit-ga |
