US2057450A - Wet refuse burning boiler and furnace installation - Google Patents

Description

Oct. 13, 1936; L.J. SCHRENK' WET REFUSE BURNING,BOILER AND FURNACE INSTALLATION 2 sheets sheet 1 Filed April 9, 1934 if/ I 6,

INVENTOR BY Moth- ATTORNEYS Oct. 13; 1936.

| J. SCHRENK WET REFUSE BURNING BOILER AND FURNACE INSTALLATION Filed' April 9, 1934 2 Sheets-Sheet 2 -MHWH M MUN- WM mi.

INVENTOR .7 %0WBY M' A TORNEYS Patented Oct. l3, I936 p u .UNIITED STATES PATENT/OFFICE.

WET REFUSE BURNING BOILER AND FURNACE INSTALLATION Louis J. -Schrenk, Detroit, Mich assignor to Combustion Engineering Company, Inc., New York, N. Y., a corporation of Delaware Application April 9, 1934, Serial No.,'l19,637 14 Claims. (01.122-2) This invention relates to boiler and furnace iners 5, rear upcomer headers 6, inclined boiler tubes stallations adapted for use in burning wet refuse, 1 connecting the headers, and suitable connecsuch as garbage, sewage screenings or the like, tions between the headers and drum; a furnace and also for burning mixtures of wet fuel and B located below the boiler having upright steam 5 relatively drier fuel, for the purpose'of generating evaporating tubes 8 at upright walls thereof a' steam. water screen C in the lower portion of the fur- I- propose to burn other fuel in space in the innace; and burner means D for introducing fuel, stallation, such as pulverized coal, in conjunction such as pulverized coal, into the combustion with the wet fuel or refuse, in order to bring about chamber of the furnace to be burned in space 10 combustion of the latter. This other fuel is therein. AsuperheaterE may be provided in the 10 directed toward the wet refuse in the furnace so 'rear wall of the furnace.

that the heat of its flame dries and ignites the wet The furnace illustrated is of the dutch oven refuse. 1 I type in which the burner means D are located to It is an object of my invention to provide a deliver fuel to be burned in space downwardly novel hearth or grate arrangement in a pulverthrough the arch of the dutch oven-F and ad- 15 ized fuel burning boiler and furnace installation jacent the front wall thereof. A draft outlet G is for the effective burning of wet refuse and the provided in the upp r P Of the installation for like in conjunction with the pulverized fuel, or drawing the gaseous products of combustion over for the burning of the latter alone when desired. the tubes of the boiler and the fuel is burned in Another object resides in associating the a U-shaped flame, as diagrammatically indicated 20 hearth or grate with an inclined water screen in Figlocated in the lower portion of the furnace. The radiant heat steam evaporating tubes 8 are A further object resides in. admitting .air into connected to receive water from and deliver steam the furnace in a manner to obtain effective comto t boile by me s of lower and pp headers bustion of both fuels being burned. 9 and I0 and suitable downcomers H and up- 25 It is also an object of my invention to provide comers l2. an arrangement whereby existing pulverized fuel h Wa Sc C Comprises a plurality of burning installations may be readily converted tubes 13 spaced apart crosswise of the furnace, as into installations especially adapted for the burni lust at d in F gs. 2 and 4 a d in in u wa d y ing of wet refuse. I from the front to the rear of the furnace. The 30 Another object is-the provision of an arrangetubes are connected at their lower ends into a. ment whereby wet refuse may be effectively downcomer header M and at their upper ends burned for the generation of steam at high caint an upcom r h ader 5, water being s pp d pacity. 7 to the downcomer header by means of downcomer 7 Other objects have to do with features of contubes l6 leading from the water space of the 35 trol which will be set forth hereinafter as they steam and water rum 4' and l ve y from th will be more readily understood in connection Wate Screen bein to t st Sp of the u with the description of the invention. 4 by means of upcomer tubes I I.

How the foregoing together with such other ob- The hearth or grate for the burning of the wet jects and advantages as may hereinafter appear 'refuse is associated with the water screen and 40 or are incident to my invention are realized, is comprises a plurality of rows of tiles or blocks l8, illustrated in preferred form in the accompany- P efe bly mad of cast o arranged o have ing drawings, whereinl air spaces, l9 therebetween as illustrated in Fig. 3. Fig. 1 is a sectional elevation through a boiler The tiles are socketed along their side edges as and furnace installation embodying my invenindicated at 20 in Fig. 4 so as to rest on the tubes 45 tion. v of the waterscreen, and have their top surfaces Fig. 2 is an enlarged fragmentary plan view, 2| inclined, as shown in Fig. 3. The tiles III are illustrating a hearth or grate detail. secured to the tubes-l3 by means of clamping de- Fig. 3 is an enlarged side view 'of the hearth; vices 22 in spaced relation so as to provide the and 3 'air'spaoes l9 between adjacent tiles, and the front Fig. 4 is a cross section on the line 4-0 of Fig. 3. edges thereof are provided with projecting por- The installation illustrated in Fig. 1 comprises .tions 23 which overhang the rear edges of the in general, a. boiler A, in this instance of the horiadjacent tiles to prevent the fuel being burned on zontally inclinedtube type, having. an upper the grate from falling through the spaces. In

steam and water drum 4, front downcomer-headaddition to the air spaces I9, I also contemplate and then takes a U turn and. flows upwardlyproviding side air openings 24 which lead to the longitudinal spaces 25 between adjacent tiles crosswise 'of the grate. At the lower end of the grate, I provide special tiles 26 which are clamped to the tubes in a manner similar to the clamping of the tiles l8 and serve as supports for the remaining tiles. At the upper end of the grate filler members 21 are provided to close the gap between the uppermost tiles and the rear wall of the furnace.

The grate extends from the rear wall of the furnace downwardly along the tubes to a point short of the front furnace wall so as to provide a space at 28 for the discharge of ash from the lower end of the hearth, it being noted that the spacing of the tubes is such as to freely permit of such discharge between the tubes. The exposed portions of the screen tubes at this point serve to prevent slagging difficulties from the burning of he pulverized coal.

The wet efuse to be burned is fed into the furnace at the upper end of the hearth by means of feeding mechanism H, in this instance comprising a plurality of rams or pushers 29 so spaced crosswise of the furnace as to provide a bed of refuse covering the entire width of the hearth. The rams are reciprocated by any suitable form of reciprocating mechanism 30, such as compressed air or steam operated cylinder and piston mechanisms.

The feeding mechanism is of a type in which the rams may be individually operated, or in unison, as desired and in which the length of stroke of the rams may be adjusted, whereby uniform flow of the refuse may be maintained under different operating conditions. Suitable hoppers 3| are provided for feeding the refuse to the rams, and the rains feed the refuse into the furnace through the medium of discharge throats 32. In order to prevent arching or packing of the refuse in the hoppers and discharge throats, these are constructed to flare outwardly in the direction of flow of the refuse.

Air is supplied to the bed of burning refuse by means of a plurality of air compartments 33 located under the, hearth, and in this instance, I have shown four such compartments. Air under pressure, preferably preheated, is supplied to the compartments 33 by means of a conduit 34 having four branches 35, one for each' compartment 33, each of which is provided with adamper 36 for controlling the flow of air. The control of air to the various parts of the wet fuel bed compensates for different rates of combustion and/or fuel bed resistance, due to distribution of the wet fuel.

Movement of the rams 29, combined with the downward slope of the hearth or grate and the method of supplying air therethrough, causes the bed of burning refuse to move over the entire length of the hearth, it being pointed out that the movement of the rams and supply of the air is so timed that when the refuse reaches the lower end of the hearth, practically all combustibles have been burned out. The ash drops off the lower end of the hearth and is mostly in finely divided form so that no difficulty from fusion of ash is encountered.

The pulverized coal burners B above referred to, admit pulverized coal mixed with primary air into the combustion chamber in a direction toward the bed of refuse andthe burning mixture travels vertically downward toward the hearth through the outlet of the furnace. The proportions of the installation are preferably such that the burning mixture makes the U shape turn at approximately two feet above the lower end of the hearth. Thus the lower nearly horizontal part of the U turn passes closely over the bed of refuse.

Secondary air is supplied through controlled ports 31 in the ,hollow front wall of the furnace for the .purpose of completing combustion of the fuel so admitted. A conduit 3'; may lead preheated airto the hollow front wall as illustrated in Figure 1. The lower portion of the fuel and flame stream sweeps over the bed of refuse in a direction opposite the movement of the bed of refuse over the hearth, and the high temperature of the flame supplies heat for drying and igniting the refuse.

I contemplate supplying air through the hearth and the bed of refuse thereon somewhat in excess of that needed for complete combustion of the refuse which aids in completing the combustion of the pulverized coal introduced by the burners D. Control of combustion may be accomplished by adjusting the amount of air admitted through the hearth to the amount of secondary air admitted through the front wall of the furnace. Stated more specifically, in burning the combined fuels with excess air through the bed of fuel on the hearth a compensating deficiency of air is supplied to the pulverized fuel stream.

Complete combustion of any volatile products of the refuse is insured because of the high temperature in the combustion chamberabove the bed of refuse so that inthe case of burning garbage, objectionable odors in the stack gases are reduced.

It is also pointed out that if it is desired at times to burn pulverized coal alone, wet refuse may be fed onto the hearth to cover it, after which the feed is stopped and the air supply through the hearth shut off.- 'Ihus, combustion of the refuse on the hearth practically ceases and the refuse remains there to protect the hearth from the intense heat of the coal flame. Although the length of time during which pulverized coal may be burned alone is limited by the accumulation of coal ash over the bed of refuse, such burning nevertheless can continue for periods of many hours and until the accumulation of the coal dust ash is sufficiently deep to bring about slagging of the surface thereof. Before this occurs, the ash on the hearth must be discharged and a new wet fuel bed provided.

When the installation is employed for the burning of garbage or the like, the garbage is partly dehydrated as by means of roller presses, in order to reduce the moisture therein, and this for the reason that the lower the moisture content, the higher the efliciency with which the garbage can be burned in the installation.

In the case of burning rubbish in which the combustible part consists of paper, wood, cloth, leather and similar materials, the moisture content is much lower than that of garbage and therefore it can be burned much more readily and makes a better steaming fuel. The rubbish burning boiler and furnace installation compris ing, a boiler, a combustion chamber, an inclined water screen, means for introducing pulverized fuel and' air into the combustion chamber di-. rected toward the'hearth, means for admitting secondary air into the combustion chamber,

means for feeding 'wet refuse onto the hearth, and means for supplying air through'the hearth and the bed of refuse thereon.

- 2. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a combustion chamber, an inclined water screen in the lower portion of and extending across the combustion chamber, means connecting said water screen into the boiler circulation,-a perforate hearth carried by and termihating short of the lower portion of the water screen, means for introducing pulverized fuel and air into the combustion chamber directed toward the hearth, means for admitting secondary .ai'r into the combustion chamber, means for feeding wet refuse onto the hearth, and means for supplying pressure air through the hearth and the bed of refuse thereon comprising a plurality of air chambers below the hearth and means for individually controlling said chambers.

3. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a-combustion chamber, an inclined water screen in the lower portion of and extending across the combustion chamber, means connecting said water screen into the boiler circulation, a perforate hearth carried by and terminating short of thelower portion of the water screen, means for introducing pulverized fuel with primary air into. the combustion chamber directed toward the hearth, means for controlla bly admitting secondary air into the combustion chamber, means for feeding wet refuse onto the hearth, and means for controllably supplying air through thehearth and the bed of refuse thereon.

' burning boiler and furnace installation compris- 4. A combined pulverized fuel and wet refuse ing a boiler, a combustion chamber, a water screen in the lower portion of the combustion chamber comprising a row of. spaced water tubes extending across the combustion chamber and inclining upwardly from front to rear thereof,

means connecting said water tubes into-the boiler circulation, a perforate hearth carried by said water screen and ending short of the lower portion thereof to provide for ash discharge at said lower portion, means for introducing pulverized fuel into the combustion chamber in a direction toward the hearth, means for feeding wet refuse onto ,the'hearth, and means for introducing air under pressure through the hearth and bed of refuse thereon.

5. A combined pulverized fuel and wet refuse burningboiler and furnace .installation comprising a boiler, a combustion chamber, a water screen in the lower portion of the combustion chamber comprising a row of spaced water tubes extending acrossthe combustion chamber and inclining upwardly from front to rear thereof,

means connecting said tubes to be supplied from and to deliver into'the boiler, a grate comprising tiles supported on said tubes and provided with air spaces therebetween for the admission of air frombelow, said grate terminating short of the lower portion of the water screen to provide for the discharge of ashes to an ashpit below, means for feeding wet refuse onto the grate, and-means.

for introducing pulverized fuel into the combustion chamber in a direction toward the grate.

6. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a combustion chamber, aninclined water screen in-the lower portion of the combustion chamber comprising a row of spaced water tubes extending across the combustion .chamber and inclining upwardlyfrom front to 7. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a. boiler, a combustion chamber, an inclined water screen connected into the boiler circulation extending across the lower portion of the combusti'on chamber, a grate comprising tiles supported on the water screen in spaced relation to provide. air spaces therebetween, means on the tiles overhanging said spaces, means for feeding wet refuse onto the grate, means for introducing pulverized fuel into the combustion chamber in a direction toward the grate. and means for passing air through the grate and bed of refuse from below.

8. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a dutch oven combustion chamber therebelow, burner means adapted to deliver fuel to be burned in space downwardly through the .end thereof, means for admitting air through the hearth and bed of refuse thereon, and a draft outlet in. the upper part of the installation for drawing the gaseousproducts of combustion over the tubes of the boiler, the distance between the arch and the hearth being such that the fuel admitted by the burner means is burned in a U-shaped flame with the bottom of the flame passing over the bed of refuse in close but spaced relation thereto.

9. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a combustion chamber directly therebelow, an inclined hearth in the lower portion of said.chamber, means for feeding wet refuse onto the hearth at the upper end thereof,'a dutch oven extension at the front of said chamber, said hearth being inclined downwardly from the rear of the combustion chamber and terminating in in the dutch oven' to be burned in space therein and in the combustion chamber proper with exit for the product of combustion from the upper part of the combustion chamber whereby a flame bending upwardly over the refuse bed is produced. 10. A-combined pulverized fuel and wet refuse burning'boiler and furnace installation 'comprising a boiler, a combustion chamber directly therebelow, radiant heat steam evaporating tubes at walls of said combustion chamber, an inclined hearth in the lower portion of said chamber, means for feeding wet refuse onto the hearth at the upper end thereof, a dutch oven extension at the front of said chamber, said hearth being inclined downwardly from the rear of the combustion chamber and terminating in the dutch oven extensionto provide an ash discharge space adjacent the front of the extension, burner means for introducing fuel downwardly in the dutch oven to be burned in space therein and in the combustion chamber proper with exit for the product of combustion from'the upper part of the combustion chamber whereby a flame bending upwardly over the refuse bed is produced.

11. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a combustion chamber therebelow, a hearth extending across the bottom of the combustion chamber and'inclining downwardly from the rear wall of the chamber and adapted to receive wet refuse, means for feeding the refuse onto said hearth at the upper end thereof, burner means adapted to deliver fuel to be burned in space adjacent the front wall'of the combustion chamber, said hearth terminating short of the front wall of the combustion chamber to provide for-the discharge of ashes to an ashpit below, and means for supplying air through the hearth and the bed ing across the combustion chamber and inclining upwardly from front to rear thereof, means connecting said tubes to be supplied from and to deliver into the boiler, a grate comprising tiles supported on said tubes and provided with air spaces therebetween for the admission of air from below,

said grate terminating short of the lower portion of the water screen to provide for the discharge of ashes to an ashpit below, means for feeding wet refuse, onto the grate, and means for introducing pulverized fuel and primary air for combustion thereof into the combustion chamber in a direction toward the grate. 1

13. A combined pulverized fuel and wet refuse burning boiler and furnace installation comprising a boiler, a combustion chamber, a water screen in the lower portion of the combustion chamber comprising a row of spaced water tubes extending across the combustion chamber and inclining upwardly from front torear thereof, means connecting said tubes to be supplied from and to deliver into the boiler, a grate comprising tiles supported on, said tubes and provided with air spaces therebetw'eegi for the admission ofair from below, said grate terminating short of the lower portion of the water screen to provide for the discharge of ashes to an ashpit below, means for feeding wet refuse onto the grate, and means for introducing pulverized fuel and primary air for combustion thereof into the combustion chamber in a direction toward the grate, together with means for introducing air through the hearth and bed of refuse thereon.

14. The method of burning wet refuse which consists in advancing said refuse over a hearth while subjecting its upper surface to the radiant heat of the flame of a fuel introduced with primary air in controllable deficient quantities for complete combustion thereof in a direction toward said surface and controllably supplying air through the hearth and the bed of refuse thereon in excess to that needed for complete combustion of said refuse, said excess supplying said deficiency for the complete combustion of said fuel.

LOUIS J. scmwnx.

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