Re: How do oil companies refine crude oil, to make gasoline and byproducts?

Dear Amy:

Your questions are actually very complicated, and the answers are 
complicated too. Fractional distillation apparatus might be illustrated in 
a college textbook on petroleum geology.  Some web sites you can try:

U.S. Department of Energy:  http://www.doe.gov/
American Association of Petroleum Geologists:  http://www.aapg.org/
Canadian Society of Petroleum Geologists:  http://www.cspg.org/
Society of Petroleum Engineers:  http://www.spe.org/

Petroleum and crude oil are the same thing. Perhaps you mean how much 
petroleum product (gasoline, heating oil, etc.) can be gotten from a barrel 
of crude oil? This depends on what products you want to make and what kind 
of crude oil you are talking about. Heavier crudes are richer in long-chain 
molecules and contain more energy. Lighter crudes are more like natural 
gas, and they are richer in smaller molecules. They are easier to work with 
but you get less out of them. The above-mentioned web sites are good places 
to look for this information too.

Good luck!
David Kopaska-Merkel
Geological Survey of Alabama
PO Box 869999
Tuscaloosa AL 35486-6999
(205) 349-2852
FAX (205) 349-2861

Moderator's note: I think that Dr. Kopaska Merkel reversed light and heavy 
crude: light crude contains MORE energy than heavy crude. Heat of combustion 
per gram goes down as molecular mass increases, so that smaller molecules burn 
hotter than larger ones.

Petroleum is separated into fractions by boiling point ("fractional
distillation"). Most of these fractions are used more-or-less as is, but 
many are processed (either "cracked" or "reformed") by various chemical 
reactions to produce more useful substances. The specific chemistry is
rather complicated; but a good college-level textbook is Wittcoff & Reuben's
book "Industrial Organic Chemicals."