Perth Amboy evening news., 1923-03-27
BURNING COAL DUST TOLD
OF BY HASKIN
Daily Letter by Frederic j. Haskin

WASHINGTON, March 27.-One
Of these days, in the not distant fu-
ture. there is a possibility that coal
destined for use in huge power
plants and industrial operations will
be transported III air tight cars in
stead of in common gondolas.
Strange as this idea may seem. there
is a good argument for the sup
position, for there is a decided trend
toward the use of finer coal and il is
not at all beyond the range of pos
sibility that powdered coal will be
a much sought-after fuel within a
few years. And in hauling powder
ed coal, type of railroad car SINH
lar to the tank car, but filled under
air pressure, might be called into
use.
Coal operators are noting with in
terest the tendency toward the use
OF finer and finer coal. The prob
lem has been widely discussed in
coal magazines by experts, and they
are wondering if the practice will
advance so far that the mining Off
Gals will be interested more in get
ting fine coal than in procuring
lump. Should this come about, this
would probably be revolutionized, as
we'll as the methods Of transporta-
ton.
1t has been only a comparatively
short time since the Introduction of
tho mechanical stoFer, furnishing as
it did a market for an otherwise
waste product. For the stoker
created a demand for slack, and
slack has long been a. white elephant
on the hands Of coal producers. it
had been piled in huge heaps at the
mine as the lump coal was market
ed. Altough the cement industry
has been using slack in pulverizod
form for a number of years, with
the coming Of the mechanical stoker
this material assumed a sudden value
because the stoker could handle il
easily. Now with the increasing trend
towar dthe use of powdered coal
other possibilities are introduced.
Pulverized coal has been used by
the cement industry for about twen-
ty-iive years, or since the develop
ment of the rotary kiln in which
the raw materials for cement manu-
facture are burned. 1t is estimated
that over 5,S00,000 tons of pulver-
lied coal were burned at cement
plants in this country last year.
However, this coal was pulyerized
by the companies themselves, be-
ing secured from the coal companies
in the form of slack. At the pres
ent time the industry is the largest
user Of pulverized coal in the coun-
try, and was the first industry to
utilize this material on a large scale.
Extreme Heat Produced
Watching one OF the giant rot
airy kilns in a plant suggests the idea
of a huge torch in operation. Some
of the kilns are ten feet in dia-
meter and 24o feet long. The pow
dered raw materials enter at one
end, and as the kiln revolVes the
slowly make their way toward the
lower end, through which the pow
dered coal ~enters. II is blown in
under pressure through a pipe and
tgnites with a roar just inside the
kiln. Frequently the fame shoots
down the kiln for distance of thir-
ty feet. OF course the kiIus are lined
with fire brick. Temperatures of.
from $500 to 5000 degrees Fahren-
heit are created and the raw ma
terials are fused to a white-hot elm
ker. Pulverized coal is used instead
or lump because II Is LnG only SUIT
able method OF burning coal In the
kilns. Much heat is lost from in
complete combustion when coarser
material is used.
Burning OF pulverized coal in the
kilns has brought out the facts that
fine grinding tends to shorten the
fame and make it hotter. The coal
is ground SO fine that S5 per cent o.
a given quantity can pass through Il
sieve having 10000 holes to the
square inch, or a sieve that is finer
than a silk handkerchief. The pro-
cedure is first to dry the coal in TO-
tary driers, and then to pulverlzc
II in special grinding mills.
OF course, the fuel problems In
the cement kilns are different from
those of an ordinary power plant.
The intense heat in the kilns is an
advantage, for it is necessary in
burning the raw materials. In pow
err plants this great heat introduces
difficulties demanding furnace walls
that will stand up under It. The ap-
paratus used i'm burning powderoG
coal in the kiln is simpler than that
demanded tor burning the same ma
terial in power plant, because spe-
cial arrangements must be made for
ash removal in the latter instance,
.awSa&fA aMya AkNang no Aar3OlIM pYObleYla