St. Paul daily globe., 1893-10-22
COAL DUST FOR FUEL.
1T WOULD EFFECT A REV0LUTi0N IN
HEATING METHODS.
SMOKE NUISANCE WOULD END.
Prof Schwackhoefer, an Austrian
Expert. Says That Many Merits
Are Possessed by the Pulvcr-
ized Carbon-Et Would Exhaust
the Warmth-Producin Prop
critics of the Coal.

heating is predicted by an eminent
European scientist as the result of a
principle recently applied to practical
firing, says the Chicago Tribune. 1t is
to use tueI only in pulverzed form,
whereby almost the eutire heating
power can be obtained from the coal
and not a particle of smoke be pro-
duced.
Pro. Franz Schwackhoefer is COM
miSsioned by the Austrian government
to study the brewing trade" "at the
worlds fair, and is stopping in this city
at the present time. He read paper
at the international congress of brew
erS held this week in which he spoke of
heating plants in breweries and malt
kilns. He has some revofC tionary ideas
in regard to heating furnaces i'll gen.
eral which involve the question of
smokeless combustion in manner that
ought to interest Chicago aud the So
ciety for the Prevention of Smoke.
Prof. Schwackhoefer has made the
matter of heating study for the last
twenty years. In his capacity as gov
ernment professor in scientific school
at Vienna. also as director of the new
scientific station for brewing at that
place, he has had ample opportunities
for making the most exhaustive re-
searches.
The professor proceeds at once to
place his argument on an altogether
different basis from that taken by most
of the engineers who have been pub
licly identified with tire question of the
suppression of smoke. Naturally, this
question is secondary in his remarks,
but the absence of smoke is so necessary
corrollary of perfect combustion that
the two things may be spoken of To-
gether. The professor then states that
the loss of heat from imperfect COM
bustion has generally been much over
estimated, even by engineers and Spe-
clalIstS; that the loss or heat by radia-
tlOn also is not so large as has been i'm
agined, but that far the greatest loss is
occaSiOned by the escape of the hot
gases and air through the smokestack.
The automatic StokerS, shaking
CRATES, Steam jets, even the down
draft furnaces the professor condemns
as imperfect. He says that our modern
CRATE firing is one of the most imperfect
technical institutions that can be im-
agined. Every form of combustion,
says he, requires certain amount of
air over and above what is necessary to
supply the oxygen needed to enter into
chemical combination with the burning
body. 1t should be the aim to keep
down this excess of air as ii will rush
through the fire chamber and escape
through the SmokeStack, carrying off a
large amount of heat. Where gas fuel
| is used about one and one-Quarter to
one and one-haIf times the amount of
air must be admitted that is theoretical
ly necessary to consume the fuel
| Where solid fuel is used, as in all our
CRATE furnaces, much larger
excess of air is required, as
the mixture with the air of the
combustible gases given off by the coal
| in the process of distillaton cannot be
SO intimate as where gas fuel is sup
piled, SO that large quantities of air
| leave the furnace without being utii--
lied. Hence the Importance of reduc-
ing the size OF the coal and the neceS-
Sity of careful firing; that is, spreading
the coal on the CRATE In an even bed, as
| the air will naturally pass through the
bare parts of the CRATE or where the
coal is thin, seeking the line of least re-
SIStance, whereas most of the air is
really required where the coal lies
thickest. In this way imperfect com
buStiOp and the formation of smoke and
SCOT will be promoted. AS matter of
| fact, people generally occupy a low
! stage of mechanical development with
respect to firing tor heating purposes.
| Millions are wasted every year IN this
| direction. 1t is known theoretically
| that it is possible to utilize 80 or 80 per
cent of the heat in coal, yet only 20 to
90 percent, or even less, is used.
! CRATES MUST BE ABANDONED,
1t is necessary to abandon entirely
| primitive CRATE fires and replace them
| by technically perfect arrangement.
Efforts have been made in this direc-
ton, but have not been generally sue
ceSSful. Gas fuel has been used in some
| industries, but the most important, and
| by far the most extensive mode of heat
| ing-namely: by steam bOilers-remains
almost as primitive as ever.
1t was only within a year or so that a
new idea was advanced, which has so
| far stood every test with such remark
able success that Prof. Schwackhoefer
does not hesitate to predict that it will
bring about a complete revolution of
the prevailing systems of firing. This
is the employment of finely distributed
coal-cOal dust.
The process consists in pulverizIng
coal into the finest particles, and blow
ing it into the fire chamber in a fine
spray by means of ventilator fans, which
agitate the air through pipes in such a
manner that it carries the coal dust
with il, and becomes intimately mixed
with it before entering the fire chamber.
There is no CRATE, no lump coal. Every
little particle of coal coming III contact
with air, there is no waste of fuel, nc
imperfect combustion. The flow of all
being regulated according to the amount
OF fuel To Ue burned, there need be nc
unnecessary excess of air, hence the
loss of heat escaping through the
SmokeStack will be much reduced. ANY
kind of coal, even screenings, can be
used, and in fact, are almost as valu-
able as the best coal. The fire can be
easily regulated. interrupted. and start
ed, just like gas fuel. But coal dust
has this advantage over gas fuel. thai
the entire heating power of the coal is
utilized, whereas in the production oil
gas a considerable amount is lost in the
generator. 1t is claimed that even a
smOkestack is not necessary where Goa
dust is used for fuel.
Prof. SchwackhOefer thinks coal dust
is the fuel of the future. 1t only re-
Quires, says he. the perfection of some
technical details which are not vet fuily
developed, but this will be matter Of
short time. Ihe loss OF heat by the
escape of hot air and gases sometimes is
as low as to IL per cent, but more
generally from 20 to 40 per cent. I'm
perfect combustion, on the other hand
which includes the escape of combusti
bic gases, flying SCOT and the loss oi
coal in the coal pit, causes a much
smaller loss of heat, except only the loss
in the ash pit. Where coal is used which
will cake this loss may be quite consider
able, the ashes and clinkers sometimes
containing 46 to 60 per cent of gooo
coal. The loss by the escape of com
bustible gasses does not exceed pei
cent. and the same figure about indi-
Gates the limit of loss by smoke ant
SCOT. The reason why this loss is over
rated, says the professor, is probably
that the smoke is visible, whereas the
source of the greatest loss-namely, the
excess OF air-is invisible. Loss from
radiation amounts to s to 6 per cent
| n Ill Eotn hot