reactor, a tank 10 feet in diameter and
40 feet long. Butane and sulphuric acid
are continuously pumped into the tank
-about a gallon of sulphuric to each
gallon of butane. Three whirling pro­
pellers inside the tank mix the two sub­
stances together.
The butane contains two slightly dif­
ferent compounds, isobutane and buty­
lene. Both are made up solely of hydro­
gen and carbon atoms, but in differen t
proportion. The magic in the process is
that the sulphuric acid acts as a catalyst,
causing a chemical reaction between the
isobutane and butylene. In this reaction
some of the hydrogen and carbon atoms
in the isobutane and butylene combine
to form the highly potent alkJ'late. The
acid settles to the bottom of the reactor
tank; it is withdrawn and recirculated
over and over again through the tank.
To replace acid that becomes contami­
nated with hydrocarbons, about five
gallons of new acid must be added for
each 100 gallons of alkylate produced.
Heat is produced by the chemical re­
action in the reactor, so here again a kind
of perpetual-motion refrigeration system
is employed. The propane-isobutane
vapors are removed from the reactor,
condensed into a liquid, and pumped
back into the reactor to hold its contents
at 50 degrees.
VVhen it leaves the reactor the alky­
late is not pure-it contains a lot of un­
converted butane which must be re­
moved. Up to this point coolness has
been the watchword in the process. Dut
now the alkylate is pumped through
three towers where heat is applied to
boil out the "fractions" not desired in
aviation alkylate. These towers are: (1)
the iso-butane tower, which removes the
iso-butane; (fl) the debutanizer, which
takes off the normal butane; and (3) the
rerun tower, which splits the alkylate
into two grades-light, for aviation
gasoline, and heavy, for automotive
fuels.
Also in the alkylate stream is a small
amount of another well-known gas, pro­
pane, which is stripped off by a special
tower called, appropriately enough, the
depropanizer.
The butane and propane may be used
either for blending into motor gasoline,
sold as liquified petroleum gas-from
whence comes the "cooking with butane"
sa.ying-or used as fuel in refinery units.
Like the meat-packing industry, which
claims that it uses "all of the pig except
the squeal," oil refineries use all of their
raw material. The self-fueling operations
of refineries are perhaps the nearest ap­
proach to perpetual motion.
Unmentioned so far is what happens
to the isobutane removed in the tower of
the same name. This isobutane is con­
tinuously pumped back to the reactor
in an operation known as recycling. This
is done because an excess of isobutane
must at all times be present in the re­
actor to achieve the chemical action
that produces alkylate.
One stubborn molecule of isobutane
might conceivably go through the plant
several times before finally breaking
down and joining with an atom of buty­
lene to form alkylate. To adopt the say­
ing of the roulette table, around and
around the isobutane goes, and where it
stops, nobody knows. But we do know
that Toledo Refinery Sohioans are so
adept at running their Rube Goldberg­
ish system that they get a lot of alkylate.
Built in 1941 to produce only fl68
barrels of alkylate per day, the Toledo
unit lately has been averaging 2,000 bar­
rels a day. On some days its output has
hit as high as fl,500 barrels.
One reason for this ama7.ing improve­
ment is the advent of the Cleveland and
Lima cat-crackers, which produce but­
tanes rich in the all-important reactants
-isobutane and butylene. Another rea­
son has been the frequent addition to the
alkylation unit of larger and more power­
ful equipment - pumps, compressors,
and the like.
But equally important has been the
conscientious attitude of the men who
operate the alky unit. Dealing with a
fickle material like butane, they must
always be on their toes, closely control­
ling temperatures and pressures through­
out the process. As they have gained
experience in the many factors involved,
their efficiency has steadily improved.
Result: more and better alkylate, which
means more aviation gasoline.
To produce the finished aviation fuel,
the alkylate is sent to the refinery
blending area. Here other Sohioans com­
bine it with high-octane straight-run
gasoline made at Toledo and isopentane
from Cleveland, in percentages of 65, 25
and 10, respectively - plus a small
amount of tetraethyl lead.
Several different grades of aviation
gasoline are made, including 91/98 oc­
tane for the airlines and 100/130 octane
for military use. One of our biggest mili­
tary customers is the Royal Canadian
Air Force, which gets about seven mil­
lion gallons a year by tanker from
Toledo RefinefJf.
The men on the alkylation unit are
indeed performing a delicate feat in re­
arranging butane molecules to put the
oomp in aviation "gas." And whether
the fuel is used by airlines or by mili­
tary, the alkalyzing Sohioans are making
a vital contribution to American strength
and security in the current "World War
fl~." So the next time you hear a sky
pilot say that he's "cooking with bu­
tane," you' can tell him there's more
butane than fiction in his remark.
01 Ethyl is on huge scales. Reading the
weightograph, Joseph Mills can tell when he
has added sufficient Ethyl to the gasoline
stream.
Straight-run
gasoline is treated to remove un­
desirable compounds before it is blended into
aviation fuel. John Pocse takes a sample for
testing.
By taking temperature of butane sample as it
evaporates, Charles Disbennett, 2nd assist­
ant operator, can tell whether the butane is
giving up the maximum amount of alkylate.
Tank