US2096267A - Fuel burner - Google Patents

Description

Y FUEL BURNER Filed April 28, 1936 2 Sheets-Sheet l INVENTOR.

Y Bit/k211i H K496177012 ATTORNEY.

7 1937- R. TILGVHMAN 7 2,096,267

FUEL BURNER FiledApril 28,1936 2 Sheets-Sheet 2 rlllllllllllllllHlrlifll H l ma 1 IN VENTOR ATTORNEY.

. *A-fuel burner constructed in accordance with Patented Oct. 19, 1937 rA'rE 'T oFFicE l f iatss'izu I, l i

B rd 'ormzer 1-, a-

ysignor to'The-"Babcock a Wilcox Company,

'Newark', N 1., acorploratlon of New Jersey I Application April 2a, 1936,. sem NoJmm The present invention relates in general to J fueL burners and moreparticularly to pulverized wfuel burners :,-adapted to ,discharge'through a {furnace-wall incorporating a row ofspaced fluid verizedzfuelto'a series ,of burnervnozzles and I ample flow areaforcombustion-air around and;

a ,1; between theiburner nozzles, minimizezdeposition g ,and; coking of the fuel on and between the ,wall 0 tubes and in the burner nozzles, facilitate access to the bumer' parts forinspection, cleaning andrepair, andwitha-reiatively low cost of manufacture, installation, and' maintenance.

The various features of novelty which characf ,teriae my-invention are pointed out with par- ,7 aticularity in the claims annexed to and forming; a partof this-specification. For a better understanding of theinvention, its operating advanhages and specific objects attained lby-lits hse,

. eference shouldbe had to theaccompanying r rawlngs'and descriptive matter in which I, have 'ment' of my invention. Ofthedrawingsr r v' ,Figsl is a sectional elevation of a pulverized fuel burning instaliationconstructed in accord ancewithmyinvention; 1 v Fig; 2 is a view mainly in section along the 7 rwcenterilinevof the fuel burner shown in Fig. l;

Fig; 3 is a'viewof one of the burner ports from-the inside of thefurnace; -I"ig.'.:4,-is a plan'view ;of -the. burner :tip shown v. Fig. ,5 is a section; taken on the line of H ,my-invention is illustrated as installed in'a horizontally inclined archofa high fuel burning ca- I Qpacity furnace 1 in which 1 the arch is normaily 1 exposed in operation to high furnace tempera- I 'fi' flttures. The archis, cooled, at its; inner side bya row of ,verticallyextending transverselyspaced 5, fluidheating tubes adapted to forma part {illustrated and described a preferred embodia flanged connection with a distributing conof a fluid circulating system, suchas that of a steamboiler receiving heating gases from the furnace; The spaces between the tubes are closed 1 'bLblocks or a layer of suitable heat resistant material. I I, except over a rectangular area de- 5 lining a burner port across which the tubes l0 extend'in uniformly spacedrelation. The fuel burning means are preferably mounted on the arch so as to discharge fuel and airdownwardly through the intertube spaces of. the burner 10 port into. the furnace.

My improved burning means comprise a casing l2 having an inlet.l2 connected to a suitablev source of secondary air for combustion, nor- 1 mally at a relatively high temperature, Along l5 theupper-and lower ends of the burner port are arranged inclined .curved bailles I3 and I4 respectively, arranged in downwardlyconverging relation. The spaces between the battles l3 and Ilandthecorresponding walls of the casing I2 are -fllled with initially plastic refractory material vll with in er surfaces shaped to cooperate with the baflies l3 and I4 in providing astreamlined converging flow path for the secondary air to the burner port around the corresponding ends of the burner nozzles, hereinafter described, tend- -ingto restrictthelateral expansion of the fuel streams in the furnace and aid in preventing ,fuel particles ;from eddying back into the air casing. An inclined baflie i6 alongone of the remaining walls of the casing contributes to this effect. The casing I 2 is illustrated as being lat- Herallysubdivided by one or more vertical partition walls i! to form separate secondary air supply'compartmentsfor a plurality of fuel burn- 3 ers arranged side-by-sidetransversely of the furnacearch. H

- My improved fuel burner is especially adapted for the burning of pulverized coal. The fuel supply means include an elbow conduit 20 external- 40 ly'of the casing. l2 and having a removable flat deflection" plate 2|- arranged in the outer wall .of the elbow. The down-stream section of the elbowi's flared transversely of the arch and has s duit 22" extending into the casing I2. The con- ,duitf22is of transversely elongated rectangular cross-section and has one pair of opposite sides shaped to provide a progressively flaring 'continuat'lon of the elbow 20 towards the discharge end, ofthe conduit 22 with its remaining, pair of opposite sides slightly converging in a normal direction. An external flange 23 is welded to the lower end of the conduit 22 and detachably per distributing conduit is relativelysmall to "facilitate uniform distribution ofthefuel thereto and reduce the cost of construction. Only. three nozzles are included in each burner tip in connected to a similar flange 24 welded on the upper end, of a burner tip member 2t.

The burner tip member 25 1s of welded construction and divided into a series of discharge nozzles 26, 21, and 28 spaced transversely of the fuel burner port and having their discharge ends terminating in a plane parallel to and at the upper or outer side of the axial planeof the arch.

tubes ll. cEach ofthe fuel nozzles is formed by a pair of curved side plates 29'and a pair of straight end plates Ill welded along their meeting edges to form a flow passage of transversely elongated rectangular cross-section. The end plates 30 progressively diverge in a direction nor- 3 'mal to the direction of flare of the conduit 22. The side plates 29 progressively converge towards F in throat ll adjacent the discharge end of the nozzle, and then diverge at an angle of approximately 15 relative to one another for the remaining portion of their length. Each of the nozzle passages'is relatively shaped and proportioned asto flow area to obtain the desirable Venturi effect and "discharge a fuel streamhaving substantially parallel straight sides. The nozzle passages are made relatively wide even at the throat 3| to reduce their tendency to plug with fuel and render them easier to'cleanin the event they should plug.- The number. of nozzles the embodiment illustrated, i. e., the oppositely arranged end nozzles 26 and 28, and the middle or intermediate nozzle 211 The adjacent side plates 29 of adjacent nozzles are welded together of pulverizedcoal and primaryair, it 'hasbeen, found in practice that the heavier, coal particles portioned to provide a cross-sectional flow areaat-their upper ends, and'the welds protected by wear bars 32.

' With a distributing conduit 22 of the'shape 11- lustrated and the elbow '20 receiving-a supply tendto flow along the narrow side walls of the conduit. To providegreaterhniformity'in the amounts of fuel discharged by the several nozzles, "the nozzles are constructed andrelatively proat the entrance end of the intermediate nozzle of the 'ehd nozzles 2 8'and 28L I 21 greater than the flow area at the entrance end In accordance with my invention, the adjacent fuel'nomles' are spaced substantially twice the spacing of the tubes extending across'the burner 'port, and the nozzles arranged to discharge against the outer side of corresponding tubes l; v The tubes in thepath of discharge of the fuel streams are provided with curved protector plates 35x shaped to. fit and welded to the outer side thereof along substantially the full length of the tubev portions extending across the burner I port. Withthis' arrangement the pulverized fuel and primary air stream discharged from each nozzle will impinge upon the upper side of the corresponding protector plate 35 and be dispersed thereby so as to discharge through the inter-tube spaces at opposite sides of the tube impinged.

I The protectorplates 35 and wall tubes upon 2 .which theyare mounted thus collectively act as,

fuel dispersal devices subdividing the individual fuel streams. V t

The spaces 36 between the nozzles open at their ends to the air casing l2 and serve as flow passages for secondary air between the fuel streams fromthe'fuel nozzles. The secondary air streams from the inter-nozzle spaces 36 are subdivided by the intermediate tubes 1 or between the intertube spaces at opposite sides, thereof,',

so as to provide converging streams of fuel and secondary .air flowing through each intertube space across therburner port. The presence of the tubes 1|) in the path of the secondary air I my airbefore coming into contactwlth the fuel streams discharged from the adjacent nozzles, and the secondary air streams deflected bythe tubes l0 tend to straighten the subdivided fuel streams entering the furnace.

streams causes the subdivided fuel streams from' each nozzle to be intimately mixednwith second-' While the intermediate nozzle 21 hasits dis- 7' charge end above and parallel to the corresponding tube ll fand-its axis of discharge normal to and intersecting the longitudinal axis of the corresponding tube, the end nozzles 28 and 28 are nozzle from the longitudinal axes 'of the corre-' sponding tubes, asindicated in1Fig.'2. This relative offset arrangement provides a substantially equal distribution of each fuelstream from the end nozzles between'the two intertube spaces at 'opposite'sides of the corresponding tube-"l0", as

the. fuelstreamsare found to be heavier towards the outer end walls of the end nozzles andunless such an offset arrangement is provided, a larger amount of fuel would-pass through the end inter-r tube spaces. The fuel streams passing through r the fuel burner; rendering it easier to inspect and remove any coke forming injthe-iritertube spaces due to thedepositionandbunring of coal particles-therein. Y

The fuel discharge'parts on the intermediate fuel nozzle 21. r

The outersurfaces of theburner tip arenorperature; and the arrangementof the burner tip in a position in which it will absorb some radiant heat from the furnace.-- 'I'hisisparticularly disadvantageous in furnaces having more than one burner and, in which not allof the burners are i Q The introduction of'the pulverized coal into'fuel nozzles having a in operation at the same time.

, vadvantageously arranged with their axes of discharge slightly oflset toward the intermediatemally exposed to higher temperatures than the inner surfaces due to asecondary air tempera ture normallyhigher than the 'prlmary airtem-' g Q high metal temperature would cause some of the.

coal particles to deposit therein and coke. To

reduce the temperature of the nozzle parts, the outer surfaces thereof are advantageously providedi'with; a layer 40" of initially plastic insulating material adapted to be held in position on the nozzle bya'multiplicity'of metallic pro- 7 jections integrally connectedto the nozzle surfaces: Suchlproje'ctions are preferably in the form of heavy nails 4| having their shankiportheir head portions at the outer end thereof.

The" nails H are interwoven with wire 1 42, as

indicated in Fig. 6. The refractory material 40 is appliedto the nozzlesurfaces'after the nails and-wire are in position, and serves as anembed ment for the same.

when one ofthefuel burners has been out of service =for-a period while the furnace is in use, the fuel discharge-parts tend to acquire arela- .1 40' I are supported in posi- 1 tion by brackets 3T mounted on the arch tubes at oppositeends of and connected to bars 38 o5 tions' welded to the surface of the nozzles and burner parts, a nozzle-ll is advantageously employed in'the elbow conduit and directed to discharge a controllable supply ofa cooling gas, such as compressed air, through the fuel burner pas- .sages before an are introduced,

while inaccordance with the provisions of the statutes I have illustrated and described herein y pulverized coal and primary air the best formsof my invention now known to me, those skilledin the art will understand that changes may be, made. in the form of the apparatus disclosed without departing from the spirit ofthe invention covered by my claims, and that a certain features of 'my invention may sometimes be used to advantage without a corresponding useof other features.

Iclaim:

todischarge through'the spaces between the wall tubes extending across said port and comprising awfuel conduit terminating in a plurality ofv transversely spaced fuel nozzles terminating at the outer side of the'plane of said wall tubes,

said nozzles being arranged so as to have the fuel'streams discharged therefrom impinge on corresponding wall tubes and be divided thereby between the. adjacent intertube spaces, adjacent nozzles being transversely spaced at least substantially twice the spacing of adjacent wall tubes, and an air supply casing surrounding said nozzles and communicating with the spaces between adiacent nozzlesand said intertube spaces so as to provide streams; of air through the intertube 'j spaces adjacentthetubes'between the tubes impinged upon by the fuel streams'discharged from 1 said nozzles.

2. In combination with a furnace wall having a I fuel burner port formed therein and a plurality of wall tubes spaced transversely of said port, pulverized fuel burning, means arranged to discharge through the spaces between the wall tubes extending across said port and comprising apul- .verized fuel conduit terminating in a plurality of transversely spaced fuel nozzles terminating at the outer side of the plane of said wall tubes,

said names having their discharge ends arranged so as to have the fuel streamsdischarged thereimpinge on corresponding wall tubes and be divided thereby between the adjacent intertube spaces, said nozzles being transversely "spaced sufllciently to impinge only on alternate wall tubes, and an air supply casing communicating I with the spaces between adjacent nozzles and said intertube spaces so as to-provide streams of air through theintertube spaces at opposite sides of the tubes between the tubes impinged upon by the fuel streams dischargedfromsaid nozzles. I 3. In combination with a furnace wall having a fuel burner port formed therein and a plurality I tively high temperature due to the radiant heat absorbed. To reduce the temperature of the .of walltubes spaced transversely of said port,

pulverized fuel burning means arranged to discharge through the spaces between the wall tubes extending across .said port and comprising a .series of transversely spaced 'fuel nozzles terminating at the. outer side of the plane of said wall tubes, saidnozzles having their discharge ends arranged so as to have the fuel streams discharged therefrom impinge on corresponding wall a fuel burner port formed therein and a plurality of wall tubes uniformly spaced transversely of said port, pulverized fuel burning means arranged to discharge through the spaces between the wall tubes extending across saidport and comprising a pulverized fuel conduit terminating in a series of transversely spaced fuel nozzles terminating at the outer side of the plane of said wall tubes, said nozzles having elongated discharge ends arranged with their longitudinal axes parallel to the axes of and so as to have the fuel streams discharged therefrom impinge on corresponding wall tubes and be divided thereby between the adjacent intertube spaces, the end nozzles having their longitudinal axes laterally offset from the axes of the corresponding tubes towards an intermediate nozzle, and an air supply casing surrounding said nozzles and communicating with the spaces between adiacent nozzles and said intertube spaces.

5. In combination with a furnace wall having a fuel burner port formed therein and a plurality of wall tubes uniformly spaced transversely of said port, pulverized fuel burning means arranged to discharge through the spaces between the wall tubes extending across said port and comprising a pulverized fuel conduit terminatingin a series of transversely spaced fuel nozzles terminating at the outer side of the plane of said wall tubes, said nozzles having elongated discharge ends arranged with their longitudinal axes parallel to the axes of and so as to have the fuel streams discharged therefrom impinge on corresponding wall tubes and be divided thereby between the adjacent intertube spaces, said nozzles being transversely spaced sufllciently to impinge only on alternate wall tubes, the end nozzles having their longitudinal axes laterally ofiset from the axes of the corresponding tubes towards an intermediate nozzle, and-an air supply casing surrounding said nozzles and communicating with the spaces between adjacent nozzles and said intertube spaces so as to provide streams of air'through the intertube spaces at opposite sides of the tubes between the tubes impinged upon by the fuel streams dis charged from said nozzles.

RICHARD H.

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