alcohol

MAhmadin MAhmadin at sciboard.spd.louisville.edu
Sat Sep 7 20:04:06 EST 1996


Hi every body:

Most gasoline which are sold on the gas stations have roughly 20% ethanol
in them, so they are classified as gashole (gasoline + alcohol).  But I am
thinking how it could be economic to make alcohol and use it as fuel.
Because alcohol is produced by microbial fermentation either from glucose
(ethanol) or from cellulose (methanol).  Concentration of alcohol just after
fermentation is around 10%.  To increase the concentration of the alcohol
usually the product of fermentation has to be distilled several times at low
temperature.  Fermentation and multiple distillation increases the
concentration of alcohol to around 90% - 95%.  More concentration is
very difficult and is only used for medical purposes.  Another way of
making ethanol is synthesis pathway in which ethylene (C2H4) combines
with the water vapour (H2O) in the presence of acatalyzer and the final
product is ethanol (C2H5OH).  Both of these processes are costly and the
price of the alcohol is probably more than $1/gallon which is the price of
each gallon of gasoline. On the other hand, because ethanol has less energy
it decreases the explosion power of the fuel and as a result the car runs less
miles per gallon compared to consuming the pure gasoline.  Although some
say that gashole is much better in the air-pollution point of view, which I
do not think the oil producing corporations are worried about.  I think how
it could be economic to produce ethanol and mix it with gasolin. In other
words my question is, how it is possible to produce ethanol so cheap.
Thanks



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