US1531255A - Method of and means for burning pulverulent fuels - Google Patents

Description

March 24, 1925 C. W. LOTZ METHOD OF AND MEANS FOR BURNING PULVERULENT FUELS Filed Jan. 9, 1920 Wi'trzeaaes INVENTOR, omwi 1 v v ATTOR Y.

Patented Mar. 24, 1925.

UNITED STATES PATENT OFFICE.

CHARLES W. LOTZ, OF PdTTSVILLE, PENNSYLVANIA.

' Application filed January 9, 1920. Serial No. 350,476.

To all 107mm it. may concern:

Be it known that I, CHARLES W. Lorz, a

citizen of the United States of America, re

siding at Pottsville, in the county of Schuylkill and State of Pennsylvania, have invented certain new and useful Improvements in Methods of and Means for Burning Pulverulent Fuels, of which the following is a specification.

My invention relates to improvements in the method of and means for burning pulverulent. fuels and especially such fuels as are deficient in volatile contents, such as anthracite, culm and coke breeze, for example.- The object of myv invention is to utilize such fuels successfully in commercial practice, to secure certain economies and better control in the combustion of such fuels, and enable the user to operate a furnace under widely divergent conditions of load.

It is desirable to maintain a relatively cool bottom or zone in furnaces of the type here considered, wherein the resultant ash may be cooled. Likewise, it is desirable, if not necessary, to'maintain the combustion in space within such furnace, i. e., above the bottom and away from its side walls, in order to prevent the otherwise destructive action resulting from. the intensely heated fuel cloud impacting within the combustion chamber. I

When prior furnaces of the type herein preferred must 'be operated at excessive rating, slagging of the bottom inevitably results. This is occasioned by reason ofthe fact that it is impracticable to build and operate a furnace with a combustion chamber of sufficient height to insure a relatively cool bottom under periods of extreme load. The formation of slag in any quantity directly upon the bottom of the combustion chamber, lIOWGVGIQ iS highly undesirable for the reason that the furnace must shortly be sliut down and the slag removed, although only with great difiiculty when solidified in a coherent mass.

Accordingly, I have devised a mode of operation and means for overcoming the disadvantages named, while attaining the concurrent advantages of cooling the slag in relatively small masses and preheating the combustion-supporting air supply of the furnace. Briefly stated, my improvements contemplate the introduction of the finely pulverized low volatile fuel downwardly within the combustion chamber, in the form of a thin curtain and with a limited air supply, which curtain is subjected to the intense heat of the deflagrating and closely adjacent reverting flame burning in space within said chamber. An adjacent slagging wall, beneath which an adequate air supply is furnished in preheated condition to the defiagrating fuel cloud, serves to accumulate the slag and as said wall preferably is inclined toward the entrance opening of the air supply, the slag is melted down from time to time and is cooled in small masses upon the bottom, from which it may bereadily removed. Under normal operation of the furnace, the air supply cools a certain proportion of fine ash which falls to the bottom and may also be readily removed together with the small masses of slag. The inclined slagg'ing wall is so positioned and the deflagrating fuel cloud so directed, that there will be no impact and consequent accumulation of partly burned fuel, accompanied otherwise by the rapid disintegration of theimpacted furnace wall. Thus, at times it is desirable positively to direct the entering. fuel cloud so that the defia ating fuel may be properly positioned wit in the combustion chamber and this is accomplished by an adjustable guide plate preferably associated with the fuel nozzle. Other features and the details of operation may be more readily explained by making reference to the accompanying drawings i1 'lustrating the preferred apparatus for practicing and embodying my invention, where- '1n:'

Fig. 1 is a composite plan and horizontal SGC-tlOllttl view (the drawings being somewhat diagrammatic in character because of the small scale required) illustrating my improved furnace.

F g. 2 IS a vertical sectional view thereof on hne 2-2, Fig. 1. Fig. 2 is a fragmentary section.

Fig. 3 is another verticalsection taken at right angles to that of Fig. 2, on line 33, and

Fig. 4 is an enlarged sectional view of the fuel-supplying nozzle and deflector.

Throughout the several figures, of the drawings similar parts are indicated by the same character of reference.

My invention is embodied and practiced preferably in a furnace of vertical type wherein the pulverulent fuel is injected within the combustion chamber by an air supply, generally in a downward direction, and is burned in a broad, reverting flame away from the bottom and walls of the combustion chamber, by means of a partial air supply from above and a preheated combustion-supporting supply at and across the bottom of said chamber. The furnace, as a whole, indicated by a, has an upright combustion chamber 12 communicating with a wide exit flue 0 near the upper portion of said furnace, and discharging through the controlled chimney stack 03 (Fig. 2 The associated boiler or other structural features are not shown, as these are unessential to the explanation of my invention.

Fig. 4 shows with some detail the preferred fuel-supplying nozzle and deflector which are positioned in the upper portion of the furnace for directing downwardly within the combustion chamber. a thin, expanding fuel cloud. This comprises essentially, the pipe a for conveying the air blast of pulverulent anthracite or other desired fuel to a wide, flattened nozzle member a, giving initial direction, dimensions and retarded velocity to the entering fuel cloud or curtain. A hinged deflector plate 6 is adjustably disposed before the passage 6' communicating with the nozzle and with the upper portion of the combustion chamber; said deflector serving to direct the fuel cloud rearwardly within said chamber, whensuitably adjusted.

The casing e accommodating passage 6' and nozzle a is provided at its upper level with shutter members f and f'- which are designed for use to control the initial air supply for the fuel cloud. Member f alone normally is open in theoperation of the furnace to furnish an induced air supply to the interior of the reverting flame or loop of the deflagrating fuel cloud. This initially is ignited by means of a wood fire on the, furnace bottom, or other suitable source of heat.

The main air supply for furthering and completing combustion is supplied from the bottom of the furnace through rear openings 9 controlled by the hinged doors 9. When the fuel cloud has been burning in the combustion chamber sufficiently to establish an intense reverting flame, as shown in Fig. 2, the incoming fuel will be ignited by heat directly communicated therefrom, as it enters said combustion chamber closely adjacent to the exit flue. Ignition takes place normally in the zone h, h and the air sup ply is directed across the bottom 5 by the ducts 9" so that it enters forwardly of the fuel curtain and rising and expanding adjacent to the front wall of the furnace, turns downwardly with the entering fuel with which it mixes to support and complete combustion, as I have endeavored to indicate by the darts in Fig. 2.

The inclined slagging wall j necessarily becomes highly heated during the operation of the furnace and an accumulation of slag 7" will form thereon, which slag, upon forcing the furnace above its normal rating, will become viscid and fall from the lip or edge of said slagging wall j into the path of the incoming air supply. Thus, said air supply serves the double purpose of cooling the slag in small masses as it falls to the bottom 11, while the air itself becomes preheated, thereby economizing the consumption of fuel. bhould the furnace be operated only at normal rating, it is requisite that the load carried by it shall be temporarily increased, say at two day intervals, in order to. melt the accumulated slag from wall j and permit the masses of cooled slag formed on the bottom 2', together with the ashes also resulting from combustion, to be removed through the doors i. This melting down of the slag may best be accomplished in practice, if the furnaces are not normally forced above their given rating, by forcing first one furnace and then another of a series or battery of furnaces, while firing the others below normal.

It is common experience, however, that furnaces must be forced during the peak or peaks of load each day, to several times their normal rating. My present invention, 1n providing the slagging wall just described and in devising the method of operation, accordingly lends itself to commercial conditions commonly met with, and, in particular, avoids the undesirable results otherwise attendant upon slagging under such conditions, or the alternative and impracticable construction of furnaces of excessive height as to the combustion chamber.

Under varying conditions of firing, it is also desirable to employ positive means for directing or positioning the fuel cloud within the combustion chamber. The hinged detlectior plate '0 maybe inwardly adjusted' when desired, usually under light or normal loads only, in order to position the flame within the combustion chamber. In addition thereto, the force of the air blast may be varied, while the stack effect may be used for controlling the air supplies, by opening or partly closing the damper d. At times the shutter f in casing 6" may also be opened to afford an additional regulated air supply at the top of the combustionichamber. However, the regulated airgsupply through the opening controlled by shutter f ordinarily is suflicient. This a-ir" supply principally secures the continuing ignition of the entering fuel cloud and supports the combustion thereof interiorly of the loop or reverting flame.

Having now described means suitable for practicing and likewise embodying my inwith vention, I claim as new and desire to secure by Letters Patent, together with such departures from method and structure as may be made merely by one skilled in the art, the following;

1. The herein described method of firing ulverulent fuels, which consists in directing such fuel downwardly at low velocity within the combustion chamber, providing therefor a partial supply of air, causing the deflagrating fuel to revertupwardly closely. adjacent to the entering fuel for subjecting it to an igniting temperature, furnishing an additional supply of air to com- .plete combustion ofthe fuel cloud in space adjacent to a. sla and the 0 eration, substantially as set forth.

2. heherein described method of firing with pulverulent fuels, which consists in ging surface, and melting directing such fuel downwardly at low velocity within the combustion chamber, causing the deflagrating -fuel,to burn in space closely adjacent to an inclined slagging surface, melting the resultant slag and permitting it to drip to the bottom of said chamber; meantime preheating a combustion-supporting air supply for the fuel and thereby cooling thesla in such form as it ma be readily handle substantially as set fort 3. The herein described method of disposing of slag resulting from'the combustion of pulverized fuels, which consists in causing the deposit of the residues of combustion in the form of slag upon an inclined slagging surface, melting the slag so that it will drip from said surface in small masses, an aircooling such dripping masses of slag sufliciently to prevent their cohesion, substantially as set forth. 7

4. In a furnace of the class described, the combination with its combustion chamber, of an inclined slagging surface rearwardly positioned within the combustion chamber, means for directing a fuel cloud diagonally downward within the combustion chamber towards said inclined slagging surface,.and

means disposed at adistance below the for ward edge of said surface for cooling the slag as it flowstherefrom, substantially as set forth.

5. In a furnace of the class described, the combination with a vertical combustion cooling the slag in small masses during inclined s ag-receiving wall, and ducts positioned beneath said wall and extending to openings adjacent to its forward lower portion, whereby a preheated air supply may be furnished to the entering fuel cloud initially in a reverse direction thereto, substantially as set forth.

7. In a furnace of the class described, the

combination with a vertical combustion chamber, of 'means for directing a fuel cloud downwardly from the upper portion and near thefront of said chamber, a rearward forwardly sloping slagging wall provided in said chamber with its lower edge disposed above the bottom of the combustion chamber, and means associated with said lower edge for cooling the slag and preventing material cohesion of the masses dripping from the slagging wall, .substantially as' set forth.

8. The herein described method of firing with pulverulent fuels, which consists in maintaining combustion thereof above a sharply inclined slagging surface, permitting the slag to build up thereon, and thereaftermelting off and cooling the slag as it flows from said surface, substantially as set forth. I

9. The herein described method of firing with fuels productive of slag, which consists in maintaining combution of said fuel above an inclined slagging surface, permitting the slag to collect thereon, and melting and causing the flow of molten slag from said slagging surface from time to time, substantially as set forth.

In testimony whereof I do now afiix my signature.

. CHARLES W, LOTZ.

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