COAL - Clpdigital.org

50
THE COAL TRADE BULLETIN.
L C O K E AND THE BY-PRODUCTS.
By T. J. EASTER,
President of the Pittsburgh Fuel & Iron Co. t
(CONTINUED FROM NOVEMBER 1).
Primary products recovered from coke, are
gas, ammonia and tar. A portion of the gas only
being needed for heating the ovens, the surplus
can be converted into illuminating gas or used for
power in gas engines in coal like Connellsville,
with 29 per cent, to 30 per cent, volatile, there
are S.000 to 9,000 cubic feet of gas to the ton. On
this basis, the 36 million tons of coal coked in
the United States last year would have produced
more than 280 billion cubic feet of gas, if all byproduct
ovens had been employed. Allowing onehalf
of the production for consumption in the
oven, we have about 140 billion, or about onehalf
the annual natural gas production during the
height of that excitement. On account of the
small percentage of retort coke ovens in use, however,
there was probably not over 5 billion cubic
feet of gas saved out of the 140 billion available.
Ammonia is recovered from the gas by "scrubbing,"
that is, the gas after being cooled is passed
through machines in which it is violently agitated
with water which absorbs it. This ammoniacal
liquor is further concentrated to desired strength.
The ammonia water used for domestic purposes.
is one illustration. In some cases the ammonia
liquor is passed through stills where distillation
takes place and the ammonia driven off, passing
through vats of commercial sulphuric acid, forms
sulphate, which is very largely used for fertilizing
purposes. An important use for ammonia is in
refrigerating factories and in the manufacture of
artificial ice. The evaporation of ammonia leaves
an intense cold, this being the prinpiple of operation.
Ammonia, i. e.. sulphate, is the most valuable
of the by-products of coke making in retort
ovens, it having a market value of $10 to $20 per
ton. The yield of this by-product from each ton
of coal is about twenty pounds, or a total yield of
360,000 tons for the 36,000,000 tons of coal coked
in the United States last year, which would have
made from $3,600,000 to $7,200,000 worth of ammonia,
had all the ovens been of the retort pattern,
and speaking about scrubbing, what could
not our "white-wings" do with that much ammonia
water in cleaning the streets of Pittsburgh?
When the gases leave the ovens, as before explained,
they pass through long mains or pipes to
the condensing house. From the moment the gas
leaves the ovens, condensation takes place, this
increasing, the nearer to atmospheric temperature
it becomes. The final traces of tar being recovered
in its passage through the various apparatus
in the condensing house. This condensate all
flows into one common settling tank, where the
ammoniacal liquor, by force of gravity, comes to
the surface, and the tar being heavier sinks to
the bottom. The tar is principally used in the
manufacture of roofing paper, and in some cases H
used for the recovery of many highly scientific
articles, usually classified under one common heading
of
COAL TAI; PRODUCTS.
One of these products is saccharine, which,
roughly, is two to three hundred times sweeter
than sugar, and is regarded as quite a boon medicinally.
Several headache powders are manufactured
from the tar, one of them a particularly
good one, inasmuch as it has not harmful effects
on the heart (antipyrene, I believe). And while
we are touching on these coal tar products, how
many realize that the rich aniline dyes are
manufactured from one of these by-products, called
benzol, which is extracted from the tar. There
are several thousand of these by-products known
to science, a greater part of which are not yet
classified. In fact, the number of compounds
that can be formed from these by-products is
indefinite and affords simply a perfect field for
chemical research.
Tar yield is about 60 to 100 pounds, or nine to
ten gallons to a ton of coal, coked, and its value
is about $5 per ton.
In their primary state, the combined by-products
of coke have a value of over $1 for each ton of
coal coked. Upon that basis, over $36,000,000
could have been reclaimed in by-products from the
coal coked in this country last year, if all byproduct
ovens had been used.
The retort or by-product system of coke making,
however, has a tendency to shift the coke
industry to the manufacturing centres, or points
of consumption instead of where coal is mined;
where the gas does not come in competition with
the natural product and where skilled labor insists
upon living.
The rate of freight is also cheaper on coal,
which contains about twenty-seven bushels as
compared with about fifty-two bushels in a ton
of coke. Of the 83,499 ovens used in the United
States in 1904, only about 2,910, however, were
retort or by-product ovens, although the year
previous, but 1,956 were making by-product coke.
Of the 4,430 new ovens building last season, 18
per cent, were of the retort pattern, showing a
growing interest in that method of manufacture.
Much can be said in favor of the
RETORT SYSTEM OF COKE MAKING
as obtaining the greatest profit from the carbonization
of coal, and there is good authority to show
that the latest devices of foreign design are making
coke which is now being used as a substitute
for the bee-hive coke, such as is made in the Connellsville
region of this state, the most efficient