US1617694A - Art of combustion - Google Patents

Description

Feb. 15,. 1927.

C. SCHWARTZ ART OF COMBUSTION Filed March 11, 1924 2 Sheets-Sheet 1 INVEA ITO R ATTORNFV(5 Feb. 15, 1927.

C. SCHWARTZ ART OF COMBUSTION INVENTOR 1924 2 Sheets-Sheet 2 ATTORNEYS WI 7775 $5 M W Patented Feb. 15, 1927.

UNITED STATES PATENT-OFFICE.

CARL SCHWARTZ, OF NEW ROCHELLE, NEW'YORK, AS SIGNOR TO INTERNATIONAL COMBUSTION ENGINEERING CORPORATION, CORPORATION OF DELAWARE.

I ART OF COMBUSTION.

Application filed March 11, 1924. Serial No. 698,409.

This invention relates to the art of 'combustion and the art of generating steam, and is especially useful in the burning of fuel in suspension, such as pulverized coal.

' In so far as the burning of the fuel is concerned, my invention contemplates the more effective and efiicient combustion there of and in a furnace requiring minimum ground area. A further object inthis re spect is to practically burn the fuel with higher temperatures, in shorter. time and less flame travel, if desired. Still another object has to do with the accomplishment of the foregoing without rapid destruction of the brick work and without forcible im pingement of the flames or refuse leaving the flame thereon.

With respect to the boiler, the invention contemplates an association thereof with the combustion chamber such that minimum floor space is taken up, it being much less expensive to take up space vertically than horizontally. Another object of'the invention is to arrange the boiler so that the heat developed by the furnace may be most elfectively applied and the work of the boiler enhanced; while at the same time the structure of the installation, considered as a whole, is simplified. A still further object has to do 3 with the reduction of dead spaces in the boilerto a negligible factor. Another obzxect has to do with an arrangement of the oiler into units stacked, so to speak, one

' over another, with circulating connections 85 such that this arrangement may be practically followed.

Thus the invention broadly eontem lates an inc ease in combined furnace and oiler efiicien'ep. 40 The oregoing, together with such other olg'ects' as may hereinafter appear or are inci cut to my invention, I obtain by means of a construction illustrated in preferred form in the accompanying drawings, where- .m:

Fig. 1 is a vertical cross section through one form of furnace embodying my invention;

Fig. 2 is a similar section showing a modiso fication;

Fig. 3 is a fragmentary section illustrating a modification of a detail of the invention;

Fig. 4 is a vertical section through a furnace and boiler embodying the invention;

Fig. '5 is a section taken on the line 5 5 tion of the boiler; and Fig. 7 is a, sectional detail of another modification.

Referring now to Fig. 1,I have therein shown a vertical combustion chamber A, of circular cross section preferably, and having an outlet- 7 for the escape of the gaseous products of combustion, under the influence of the draft, at the top. The lower part of the chamber is preferably hopper shaped with a gate controlled outlet 8. The chamber may, if desired, have a smaller horizontal dimension than customary and the height is such that combustion is completed before the flames reach any evaporating surfaces over the outlet. The height, relatively considered, may also be less than usual, i. e. the flame path may be. shorter. This may be brought about by the manner of admission and burning of the fuel now to be described.

The fuel, in suspension, is admitted through a plurality of burners 9, in opposing and impinging substantially horizontal streams, at a point well above the bottom or floor of the chamber. Air may be supplied at the burners, as by induction, as illustrated. The velocity of the fuel streams is such that the fuel is effectively carried in, without, however, producing a surging so violentas to'forcibl carry-the flames to the walls or to cause t e space in the bottom to be fully occupied by flame. On entering, the streams promptly ignite, the lighter particles rismg underthe draft and the 'cores impinging, producing a central eddying securing proper admixture to further combustion. Here, again, lighter particles, exploded particles, and gases liberated rise under the draft, and heavier particles of fuel may fall. In falling, they meet with or pass into an underlying strata of air supplied thrpugh a multilicity of inlets 10 in the walls of the chamber. They are there exploded and burn, becoming practically instantaneously broken up and gasified, whereupon the draft be-j comes efi'ective thereon and they move upopenings 11, preferably damper controlled if they be made of substantial size. The rising stream thus progressively meets fresh air,

drawn in by induction and at right angles,

whereby a slight peripheral eddying is set:- up furthering combustion. The film of air also protects the wall against erosion; lt practically the greater portion of the air for combustion be admitted with the coal, then the size of the inlets 10 and 11 will be cut down so as to minimize the amount of excess air while still preserving the protective features. Under such conditions, the flame will be short, bright and extremely hot. If less air be admitted to the-burners, the size of the inlets ma be well increased, whereupon the flame wil be longer and less hot.

In any event the bottom of the chamber should be cooled to prevent the coalescence of the precipitating refuse into liquid slag, if the bottom of the chamber wall is made. of refractory material. In the arrangement shown, the air admitted through the inlets 10 serves to cool the ash and to perform the other functions mentioned. The deposit is therefore readily removable.

In the arrangement of Fig. 2, the chamber is bellied out in the region where the fuel is admitted to make it possible to reduce the extent of eddying or to avoid the detrimental effects ofextensive cddying,-and to hold up the flame higher from the bottom. It also afi'ords an opportunity for a greater progress of combustion before impingement occurs.

In the arrangement ofFig. 3, the air is admitted in such manner as to sweep the wall circumferentiall As to the combustion chamber of Figs. 4, 5 and 6, the wall is hollow and air may be introduced into the space under pressure through a pipe or pipes 12, flowing into the combustion space in jets through a multiplicity of relatively small or tin openings 13, functioning, in essentials, as t ose before described. The preheating of the air is advantageous as the furnace temperatures are not lowered as greatly. The walls are also additionally protected by the absorption by the air of someheat therefrom. The fuel is admitted in a lurality of streams between which a plurality of streams of air are admitted, as at 14, all streams converging. Intimate'admixture is thus secured, less-air need be supplied through the chamber wall, and the flame may be shorter and hotter.

\Vith reference to the boiler, I have proceeded upon the assumption, using a horizontal boiler for illustration, that the first pass is the boiler proper, where about of thework of evaporation is performed, and that the subsequent s are practically economizer sections, andicapped by dead spaces. About 60% of the work of the first pass is performed in the lowermost tubes.

1 therefore propose (to divide the boiler into short sections or units, stacking them over the outlet 7, one above the other. The lower unit 15 does the work of the first pass, and the higher units 16 of Fig. 4 and 16 and 17 of Fig. 6 do the work of the other economizer passes. The gaseous products, however, rise successively through the units and are more effective] y applied. The dead space is ne ligible, if existent at all. Each unit is simp e. The lower unit may have larger tubes than the others and the space around the tubes may be less in successive units or progressively less in a unit, to compensate for the contraction of the gases and to provide for maximum heat transfer. Less draft. may be used as there is no reversal of the gases.

Because of different conditions as to circulation I prefer to have each unit connected to have self confined or local circulation, in order to avoid difficulties which might otherwise be encountered, In the arran ement of Fi 4, I connect the low point of t e unit 15 wit the drum 18 by means of a. large pipe or pipes 19, and the high point by means of t e pipe or pipes 20, also large. The unit 16 is similarly connected with its drum 21 by pipes 22 and 23. The setting is simple.

In the arrangement of Fig. 6 substantially the same arrangement is followed for each unit.

Referring to Fig. 7, the space in the hollow wall is divided into compartments to each of which air is supplied through the casing 24 by the damper controlled inlets 25. By this arran ement regulated control of the air supplieil into different areasof the chamber may be obtained to the end of securing nailrimum efficiency in the burning of the I claim:

1. In the art of combustion, the method of burnin pulverized fuel in a substantially cylindrical vertical boiler furnace having an outlet at the top, which consists in in ecting the fuel in suspension in a plurality of su s tantially horizontal converging streams into the lower part of the furnace chamber, in i iting the streams of fuel, in admitting com ustion air below the convergin streams, in drawing the burning fuel an air upwardly in a, column toward the outlet under the influence of the draft, and in admitting additional air at a multiplicity of points around the periphery of the column substantial] throughoutits length sufficient to protect the wall of the chamber from forcible impingement of the flame and to burn the fuel completely before said column reaches the outle 2. A boiler furnace for the combustion of pulverized fuel, comprising, in combination, a substantially cylindrical vertical combustion chamber, a plurality of peripherally spaced and substantially horizontally dis posed fuel and air injectmg nozzles near the ottom of said chamber,and a multiplicity of peripherally disposed air inlets throughout the greater part-of the height of the chamber.

3. A boiler furnace for the combustion of a substantially cylindrical vertical combustion chamber, a plurality of peripherally spaced and substantially horizontally disposed fuel and air injecting nozzles near" the bottom of said chamber, a multiplicity of peripherally disposed air inlets throughout the greater part of the height of the 1- path of travel for the combustion stream 2 from the point of entry.

In testimony whereof, I have hereunto signed my name. 1

' CARL SCHWARTZ.

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