US1762319A - Art of generating steam by the burning of fuel in suspension - Google Patents

Description

June 3U, 1930. w; R. WOOD l ART orf GENERATING STEAM BY THE BURNING oF FUEL 1N SUSPENSION Filed Jan. s, 1927 2 Sheets-Sheet l ATTORNEYS June 10,r 1930.

w. R. woo'n 1,762,319

ART` OF GENERATING STEAM BY THE BURNING OF FUEL IN SUSPENSION 2 Sheets-Sheet 2 y 1/ fm A TT ORNE K5' 40 vent destruction of the burner, to which end Patented June 10,` 1930 UNITED STATES PATENT OFFICE WILFRED R. WOOD, OF LONDON, ENGLAND, ASSIGNOR TO INTERNATIONAL COIL BUSTION ENGINEERING CORPORATION, 0F NEW YORK, N. Y., A CORPORATION OF DELAWARE ART OF GENERATING STEAM BY THE BURNING OF FUEL IN SUSPENSION Application lerJ'anuary 8, 1927. Serial No. 159,968.

This invention relates to improvements in the art of generating steam by the burnin of fuel in suspension or space, and is particu arly useful where the fuel is in finely divided form, as, for example, powdered coal or coke.

The invention will be described in connection with the burning of pulverized coal. It has heretofore been proposed to introduce powdered coal in an upward direction through the bottom of a combustion chambern With this type of ring, difficulties have been incurred because of bird nesting amongst the boiler tubes, the disadvantages of which are vwell understood in this art. This diiiiculty is largely due to the fact that the fuel was admitted substantially in the line of the draft, in consequence of which there were not only objectionable losses in combustible values, but also there was combustion amongst the tubes and other factors contributing to the formation or collection of obstructing deposits on the tubes. It has also been proposed to introduce the fuel horizontally with a vertically widely spreading flame, which is objectionable for substantially similar rea.- sons.

It is one of the objects of my invention to overcome this difficulty, and I am enabled to do so by so admitting the fuel into or near the bottom of the combustion chamber or space that it is, essentially, directed toward the sides of the combustion chamber so as to produce a mushroom flame.

This may, under some conditions of operation, particularly where the boiler is being forced to very high rates, result in destruction of the refractory walls. It is another object of my invention to overcome this difficulty.

A further object of the invention is to pre- I propose to cool the burner.

I also propose to provide a preferred ar` rangement in which the burner is not liable to become clogged up by ythe deposition of' refuse adjacent thereto, to which end I have the burner projecting well up from the bottom or the door of the combustion chamber, and arrange cooling pipes above the Hoor, preferably approximately at the level of the upper end of the burner, said pipes being relatively widely spaced so that gravitatin refuse can freely pass therebetween for fina deposition on the floor of the combustion chamber.

Another object of the invention is to provide an arrangement which is of simple character, and which, if desired, may be largely standardized by virtue of which existing boiler installations can be readily and effectively converted into high capacity installations.

Insofar as the new boiler installations are concerned, I propose to provide an improved and effective radiant heat boiler of relatively simple construction, small size, and very high capacity, so burning the fuel that maximum radiation is secured.

How the foregoing, together with such other objects and advantages as may hereinafter appear, or are incident to my invention, are realized, is illustrated in the accompanying drawings, wherein l Fig.' l is vertical section through a boiler furnace illustrating` the application of my invention to an existing boiler of a horizontal type.

Fig. 2 is a partial cross section taken on the line 2 2 of Fig. l.

Fig. 3 is a diagrammatic view illustrating a riodification of a detail o'f my invention, an

Fig. 4 is a vertical section illustrating another embodiment of rnv-invention.

In association with Figs. 1 and 2,- I will describe the invention as employed in converting an existing boiler installation, al though, of course, it is to be understood that a new installation may be similarly constructed. Referring to these figures, it will be seen that the reference character 7 denotes a horizontaltubular boiler, beneath which is a refractory throat or setting 8 carried on suitable metallic structural work 9. The setting preferably carries the boiler.

Beneath the setting 8I I arrange a unit in dicated as a whole by the reference letter A. This unit comprises a preferably circular wall 10, which wall is composed of refractory material, and is of relatively light construction; the rma 0f exposed substanwhich are connected into arcuate headers 12;-

the screen indicated las a whole by the reference letter b; andthe burner indicated. as a whole by thev reference letter c; and appropriate downcomer and riser connections .to

y bexmore specifically described hereinafter.

The wall.. 10 and the tubes 11 define a combustion chamber beneath the setting 8, which latter, in effect, forms al continuation thereof.

The floor 13 of the combustion chamber is preferably hopper shaped, as shown, with a number of gate Valve controlled outlets 14 for the dumping of refuse. A hollow refractory column rises from the bottom at the center, and within this column is located the burner c. This column supports the arcuate headers 16 of the screen b. A ring of short pipes 17 connect the arcuate headers 16 with similar arcuate .headers 18, such pipes'serving to support o`r position the latter headers from the former headers. Extending radially outward from the headers 18 are relatively widely spacedtubes 19 which connect at their outer ends with the arcuate headers 12. Similar tubes20 extend radially outward from the headers 16 to arcuate headers 21 .located exterior of the combustion chamber.

Junction boxes 22-preferab1y arcuate are arranged at intervals around the combustion chamber above the headers 21, and are connected to 1 theA latter by short tubes 23. The junction boxes are connected by one or more downcomers 24 to a water space of the boiler, such as the bottom portion of the headers 25 thereof. The downcomers 24 are so shaped or arranged that, for all practical purposes, the downcoming water has the same distance to travelfr'om the headers 25 to the junction boxes.`

The upper ends of the tubes 11 are connected into arcuate headers 26,which, in turn, are connected bythe pipesl or tubes 27 to j unction boxes 28 similar to the junction boxes 22. The junction boxes 28 are connected by risers 29 to a suitable point of the main boiler, such as the headers-30 thereof, the risers 29 being so arranged that the steam must travel substantially the same distance from all junc- -tion boxes 28 to the headers 30.

The circulation is indicated by the arrows.- The clean-out plugs 31 for the headers 12 are accessible from the exterior. The clean-out plugs 32 for the headers 18 are made accessi- .ble by raising the burner casing 33, which casing is suspended from its upper. end on` the headers 18. The cleanout plugs 34 for the headers 16 are accessible by raising the burner casting. All other boxes, headers and plugs are exterior of the combustion cham er, and, therefore, readily accessible.

Referring, now, to the. burner c, this may be of any preferred construction calculated to carrying air, and is sprayed outward in the manner described mixing with the balance of the air required for combusion, which is preferably supplied through the casing 33. This air may be supplied under pressure by a fan not shown, and may lead from anair preheater not shown.

The mushroom ame produced by the burner is a clear intensely hot flame, and, vertically considered, is relatively narrow. This has the following advantages: Better transmission of heat by radiation is secured; the fuel is not discharged in the line of the draft, and combustion is complete within the combustion chamber, so that the loss in combustible values through the boiler is negligible, and honeycombing is prevented. The combustion space is primarily defined by exposed tubes subject to radiant heat, and, therefore, a large capacit is developed. Furthermore, with the hot ame, the rate of heat transmission is higher. In addition, a higher rate of combustion can\be maintained with negligible dust loss, say, for example, in

the neighborhood of from 30,000 to 35,000 B. t. us. per cubic foot of combustion space. Thus, a relatively small combustion space can be employed and high capacity secured from a relatively small boiler.

The tubes 11 protect the wall 10, even if, at very high rates of firing, the flame should happen to impinge thereon. vThe tubes 11 being upright, rapidly 4relieve the tubes 19 of the screen of steam, and this, with the downcomer head of water, ensures rapid circulation through the tubes 20 and 19, preventing burningl out thereof, as well as securing the benefits of more rapid circula'- tion throughout the entire boiler system. The tubes 11 are preferably finned.

The screen, because of its arrangement, has a very appreciable cooling eii'ect aty the center around'the burner, and, consequently, the y l burner is protected. The refuse particles pass freely between the tubes 19 and the tubes 20 and deposit in the hopper shaped bottom, and are readily removed from time to time. It is also to be noted that the unit A ma be largely composed of standard parts which .tends to simplicity and economy in manufacbe dispensed with, and the -4, this shows a furnace shaped boiler, i. e.,

a boiler arranged to define its own combustion chamber. As shown the chamber is rectangular in cross section instead of circular. This and other straight sided arrangements are more economical. The burner or burners may be arranged as before, or in any other way, producing a mushroom-like flamecalculated'to reduce dust and combustible gas loss.

I claim:

1. In combination, a boiler, a substantially circular combustion chamber therebeneath having side portions thereof lined with exposed tubes in the circulation of the boiler, and burner means at the lower part of the chamber for providing a mushroom shaped flame the axis of which is substantially coaxial with the axis of said chamber, said chamber being also provided with cooling tubes in the circulation of the boiler and extending in proximity ,to the burner means.

2. A unit for installation under boilers comprising a cage of tubes open at the top, means for connecting the cage into the circulation of the boiler whereby flow takes place through the bottom tubes of the cage and from thence through the side tubes of the cage, said means including downcomer means from the boiler to the cage and upcomer means from the cage to the boiler, a casing for the cage providing an ashl receiving space therebelow, and burner means located in the bottom of the cage the axis of the burner means being substantially coaxial with the axis of the'cage.

3. In combination, a pulverized coal burning combustion chamber of substantially circular form having metallic, cooled walls, burner means for bur-ning the pulverized coal with a mushroom-like flame, and a water ring of tubes arranged to protect said burner means, the axis of the burner means being substantially coaxial with the axis of the chamber.

4. In combination, a 'pulverized coal burn' ing combustion chamber of substantially circular form having cooled metallic walls, a.

water screen in the lower part thereof comprised of spaced water tubes, and burner means at the bottom of the combustion chamber for burning the coal with a mushroomlike ame the axis of which is approximately vertical and coaxial with the axis of the chamber. 5.' In combination, a pulveriz'ed coal burning combustion chamber of substantially circular form having burner means at the bottom thereof for burning the coal with al mushroom-like flame, the axis of said burner means being substantially coaxial with the axis of the chamber, and water tubes arranged to create a cool zone below the point of fuel introduction.

6. In combination, a boiler, a substantially 'circular combustion chamber therebeneath including steam generating elements arranged to constitute the upright walls thereof, spaced steam generating elements defining the bottom thereof, burner means for introducing fuel into said chamber thru an opening'in said bottom in a manner to produce a mushroom-like flame, said steam generating elements being connected to deliver the steam generated thereby to the boiler and to re ceive water from the boiler and the axis of the burner means being substantially coaxial with the axis of the chamber.

7. In combination, a boiler, a substantially circular combustion chamber therebeneath having side portions thereof lined with water tubes in the circulation of the boiler, spaced water tubes in the circulation of the boiler arranged to constitute a bottom screen for the combustion chamber, and burner means at the lower part of the chamber for introducing fuel into. the chamber with a mushroom shaped flame, the axis of said burner means being substantially coaxial with the axis of the chamber.

8. In combination, a boiler; a combustion chamber therebeneath having side portions thereof lined with water tubes, water screen tubes at the bottom of said combustion chamber, and a burner at the bottom of the chamber for producing a mushroom flame the axis of which is approximately vertical and coaxial with the axis of the chamber; and headers at each end of the side tubes intol which said tubes connect, the water screen tubes connecting at one end into the headers at one end of said side tubes; headers atthe other end of the screen tubes into which they connect, said headers being disposed adja- WILFRED R.A woon.

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