The products produced from crude oil are separated into several classes
by volatility -- gasoline is the lightest and road tar is the heaviest
-- gasoline production these days is a bit more complicated than just
collecting the light fraction, as was true 50 years ago (and up to
about 1970, anyway).
Crude oil is made up of hundreds of compounds, ranging from one carbon
(methane) to 50 carbons or so, mostly linear chains of carbon atoms,
but quite a bit in circular forms (benzene based compounds) as well.
The lower the carbon number, the more volatile the compound is.
Gasoline is composed of compounds with carbon number less than 12, with
nearly all of it less than 8. There will be some traces of high carbon
number compounds -- this is what is left in a tank of fuel that has
evaporated, along with the non-volatile detergents, fuel additives, etc.
# 2 Diesel fuel is C12-C32, with the largest amounts being C17 to C19
or so, depending on grade. #1 is lighter, kerosene is C8 to about C16,
and there are other distillates available with other carbon number
ranges (lighter fluid, for example).
Jet fuel has some components of the gasoline but is much heavier, and
comes in two grades (JetA and JetB) -- JP4 is no longer available.
That was "wide cut gasoline" -- gas with some kerosene in it. Very
explosive due to high vapor pressure.
What fuel costs is a variable kinda thing -- we are currently importing
large amounts of gasoline from Europe to make up for lack of refining
capacity in Louisiana, but I'm not sure of how much diesel is coming
over. Demand for diesel is very high -- home heating fuel is basically
#2 diesel with red dye so you won't use it in the car without paying
the fuel taxes (don't get caught if you do, the fine is MUCH more than
paying the road tax....even today!).
The amount of diesel produced is going to be impacted (I hate that
word!) by the stockpiling of winter heating fuel, the demand for jet
fuel, the demand for truck and train use, and the willingness of people
to fork over cash -- this is a "free market" economy, (another term I
hate, since there is no such thing) -- you can charge anything you want
and make any kind of profit you want unless someone stops you or
refuses to pay, and it's illegal to stop someone making huge sums of
money on necessites.... The amount of gasoline being taken out will
also have an effect, although it's pretty hard to change the carbon
number of the components without expending too much energy.
The real solution to high fuel prices is to stop using it, but that is
going to take undoing 60 years of full government support of
profiteering in the oil, housing, and automotive market.
Peter
