REAL  ESTATE





AND







(Copyright, 191V, by The Record and Guide   Co.)





NEW YORK, APRIL 14, 1917





GETTING  THE GREATEST EFFICIENCY FROM COAL

Prices Are in the Ascencdancy and Building Managers
Must Use Every Endeavor to  Obtain Best Results





THE price of coal is in the ascendancy
and not for years -will it be less than
in 1916. This is obvious for many rea¬
sons, such as the increase in mining
costs, the difficulties of transportation
due to car shortage, the passing out of
the culm banks that have given us a
reserve supply for the last thirty years,
and the increased demand for a fast di¬
minishing product. So it behooves all
to make scientific combustion our main
problem and to give to it the attention
it deserves.

The United States Geological reports
showed that in 1916 there were more
than seven hundred million tons of coal
mined and of this amount thirty per
cent, was wasted in a way that can be
classed as a preventable loss because it
was due to inefficient combustion. This
preventable loss in money amounts to
more than one billion dollars. In my
short discussion on coal and its con¬
sumption I will treat it from a com¬
mercial or dollars and cents point of
view rather than from a technical  side.

The first and one of the most im¬
portant steps in coal consumption is to
provide adequate bunker capacity to
meet the needs of your plant. Some of
our buildings have so small a bunker
capacity that thev will hold only enough
coal for a two days' run; others have a
capacity for a week's supply and there
'are but few buildin.gs that have a capa¬
city for a month's supply. Every build¬
ing should have a bunker capacity for at
least one month's run. This would tide
over any temporarv shortage due to a
strike or bad weather. This is a vital
point and should be given the first con¬
sideration  in laving out your plant.

Now we shall consider the kind of
coal to be used. In selecting the kind
of coal to burn you should choose the
kind of coal that gives vou the lowest
cost per million B. T. U.'s and one that
will also meet the physical conditions of
your plant. In this market we have the
following steam coals from which to
choose: namely, soft, pea. and No. 1.
No. 2 and No. 3 buckwheat. I will
briefly discuss each of these. Because
of its high cost delivered into New York
and the difficulty in procuring it, soft
coal is practically excluded from our dis¬
cussion. Furthermore, the smoke aris-
ins from it. being in violation to a city
ordinance, would prevent its use to any
great extent except in plants enuipped
with automatic stokers, even if the cost
were not so  great.

Pea and No. 1 buckwheat have a high
cost per million B. T. U.'s when com¬
pared with No. 2 and No. 3 buckwheat.
These four coals have about the same
heat value, but No. 2 and No. 3 buck¬
wheat are, of course, much cheaper ner
ton than pea and No. 1 buckwheat. No.
3 buckwheat has the lowest cost per mil-
linn B. T. U.'s but it may not be pos¬
sible to burn this coal in all plants be¬
cause of lack of draft. If it is possible
to secure a draft of from .25" tn .6" at
the front of the furnace and ll^" at the
foot of the stack, vou then have suffi¬
cient natural draft to burn No. 3 buck¬
wheat. Should natural draft conditions
prevent your burning No. 3 buckwheat





By CHARLES A. FLYNN, M. E.

and if it would not be an economic in¬
vestment to install forced draft, then
you should fall back to No. 2 buck¬
wheat or even to No. 1 buckwheat.

Having decided on the kind of coal
you are going to burn, the next step is
to equip your boilers with suitable
grates, properly designed as to type and
kind, for the coal you are to burn. The
grates in common use to-day are the
shaking, the stationary and the dumping
types. The shakinT type of .erate has
gone into disuse for the smaller sizes
of coal, owing to the loss of coal with
this grate and the disturbing of the fire
bed bv shaking. Stationary grates have
the following weak "oints: the length of
time it takes to clean the fire (and the
consequent loss of steam), the necessity
of pulling the dead fire out in front of
the boilers and the loss of coal due to
the difficulty of separating the live and
the dead coals during the cleaning proc¬
ess. The dumping grate gives by far
the best service for the smaller sizes of
coal. The fires can be thoroughly and
rapidly cleaned with practically no drop
in steam pressure.

The kind of grate and the proper air
space for the coal you are using should
be given careful thoueht. Herringbone
grates having from 20 per cent, to 40
per cent, air space are admirably suited
for No. 2 and No 1 buckwheat and pea
coal. Pinhole grates having from 15
ner cent, to 20 per cent, air space are the
kind most used for No. 3 buckwheat.

Next Logical Step.

The next logical step is to make sure
tbat the furnace linings, bridge wall and
baffle walls are in good condition and
air tight. Your furnace bricks should
be placed as close together as possible
tn avoid approaching a stucco eflfect in
the furnace. The bond between the
bricks should be a fire resisting mate¬
rial havincr a melting temperature near
tn tbat of the fire bricks themselves.
Tbis insures a firm wall and prevents
the bond between the bricks from melt¬
ing and running away, which would
cause  the  brickwork  to  sag.

Tbe outside brickwork should be kept
air tight to prevent air infiltration. This
can be done bv cuttin? out and pointing
all cracks, repairing all Ino'ie bricks, and
then covering the entire brick work with
a nondrying plastic asbestos compound.
Cover vour steam drums with asbestos
and calk up around the dust doors, all
metal work   and breeching.

Having determined on the size of the
coal best suited to your plant and as¬
suming that you have placed vour boil¬
ers externallv and internally in the best
pbvsical condition, we now come to the
main issue—the efficient burnin<r nf cnal-
That is obtaining all the available heat
in tbe coal and tbe absorbing of this
available heat by the bnilers. Inas¬
much as furnace and bniler efficiency
are nften confused and thought identi¬
cal, it might be well to state that one
clear wav to differentiate between the
two is tbat furnace efficiency is the
amount nf heat we get out of the coal,
while boiler efficiencv is the amount of
heat that is converted into steam. Com-
binin.g these two efficiencies we get the
thermal efficiency of the boileri_______.





We have four comparatively simple
and inexpensive devices to check fuel
consumption: the first, a water meter or
some weighing device properly cali¬
brated to measure the amount of water
going into the boilers; the second, a dif¬
ferential draft gauge attached to the
front of the furnace to measure the draft
passing through the fire; the third, a
portable Orsat machine to take CO»
readings; the fourth, a recording stack
thermometer installed at the stack side
of the end boiler. The above pieces of
apparatus can be bought and installed
for about $180 on a basis of three
boilers and for additional boilers the
cost per boiler is very ;niall. The object
of this apparatus is by a check proc¬
ess to obtain the highest thermal ef¬
ficiency of the boiler.

The use and purpose of a feed water
measuring apparatus I am sure is clear
and well known to you all. The differ¬
ential gauge should take as important
a place in your boiler room as the ther¬
mometer does in a physician's bag, for it
surely indicates just what is taking place
in your furnace. It shows immediately
whether the fires are too thin or full of
holes or whether they are too thick and
becoming dirty. If you have two or
more boilers running at one time your
combustion problem can be simplified to
one operation by regulating the individ¬
ual dampers on each boiler so the gauge
on each boiler reads the same. Then
changes due to atmospheric conditions
or changes of load can be easily taken
.care of bv changing the main flue
damper. The CO2 or flue gas analysis
apparatus tells you whether you are get¬
ting too little or too much air for cgm-
bustion and it is by means of a CO2 ma¬
chine that we determine the correct
draft that gives us the highest CO2 with¬
out CO. Lastly, we have a recording
stack thermometer which shows at all
times the temperature of the flue gases
as thev pass out to the stack.

All four pieces of apparatus work to¬
gether and each acts as a check on the
other to give us the highest combined
efficiency of furnace and boiler. Set a
high thermal efficiency as an ideal and
keep that as a standard toward which
to work.

The care and upkeep of boilers will
do much to maintain this efficiency.
Keep the soot from boiler tubes by
blowing the dust oflf every day. Blow
down boilers, one and a half gauges, at
least once a day. Clean the boilers at
least every six months, seeing that the
headers, mud, and steam drums are per¬
fectly clear of dirt or even a sugges¬
tion of scale. If this is done you will
never have need of boiler compound.
Here again the dififerential gauge comes
into use and shows us the condition
nf the tubes. By taking readings in the
first and final uptake we can readily
learn whether there is any draft inter¬
ference due to  soot accumulations.

When we review the winter we have
just passed through with its coal short¬
age and the enormous prices we have
paid for coal each and every one of us
must re.qlize the great necessity of burn¬
ing coal efficiently and economically.
Todav should one of our local mer¬
chants announce that he would sell coal