Columbia University Libraries Digital Collections: The Real Estate Record

Real estate record and builders' guide: [v. 99, no. 2561: Articles]: April 14, 1917

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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