US1759038A - Apparatus for burning pulverized fuel - Google Patents

Description

May 20; 1930. v. z. CARACRISTI APPARATUS FOR BURNING PULVERIZED'FUEL Filed May 6, 1921 6 Sheets-Shet IN VEN TOR.

ATTORNEYS.

May 20, 1930. v. z. CARACRISTI APPARATUS FOR BURNING PULVERIZED FUEL Filed May 6, 1921 6 Sheets-Sheet May 20, 1930. I v. z. CARACRISTI 1,759,033.

' APPARATUS FCR BURNING PULVERIZED FUEL Filed May 6, 1921 6 Sheets-Sheet 4 ATTORNEYS.

May 20, 1930. v. 27 cARAcRlsTl APPARATUS FOR BURNING PULVERIZED FUEL Filed May 6, 1921 6 Shee s-Sheet INVENTOR. Wd mw' sj ATTORNEYS.

May 20, 1930. v. z. CARACRISTI 1,759,038

APPARATUS FOR BURNING PULVERIZED FUEL Filed May 6, 1.921 6 Sheets-Sheet 6 ATTORNEYS Patented May 20, 1930 UNITED STATES VIRGINIUS Z. CARAORISTI, OF BRONXVILLE, NEW YORK, ASSIGNOR 'IO COMBUSTION ENGINEERING CORPORATION, A

PATENT OFFICE CORPORATION OF NEW YORK V APPARATUS FOR BURNING IP'O'LVEBIZED FUEL Application filed May 6, 1921. Serial No. 457,345.

This invention relates to an apparatus for burning pulverized fueland is particularly useful in the generation of steam.

It has for one of its objects the eflicient burning of a given quantity of pulverized fuel in less time and in a smaller furnace than heretofore practical. As another ob ect my invention is intend d to reduce den 7 areas to a minimum, 1. e. to utilize full furnace space to best advantage. i

A further object is to make an efiicient applioation of; pulverized fuel to a boiler such as the Ladd type.

Still another object is to provide a novel and improved arrangement of ash pit, combustion chamber, boiler and stack, tending to procure simplicity in'construction, opera-. tion and maintenance.

- My invention also contemplates an improved arrangement for simpl and eifectively carrying on the pulverizmg, separating and delivering operations, especially where there is a battery of boilers. I

he foregoing, together with such other ob'ects as may hereinafter appear or are incij cut to my mvention, I attain by means of;

a method and apparatus, the preferred embodiments of which are illustrated in the accompanying drawings, wherein:

Fig. l is an end elevation of a battery of boilers embodying my invention, the furnace, boiler setting, and associated structure for one boiler being in section as indicated by the line 1-1 in F1 3.

Fig. 2 shows a f ragmentary section taken as indicated by the line 2--2 in Figs. 1' and 3, on a larger scale.

Fig. 3 is a somewhat diagrammatic plan view of a portion of an installation, parts above the section line 33 in Fig. 1 being broken away and removed.

Figs. 4 and 5 illustrate an installatlon embodying my invention in modified form ;'F1g. 4 being an end elevation similar to Fig. 1, and Fig. 5 a plan view with parts above the section line 55 in Fig. 4 broken away and removed. I

Fig. 6 is a more or less diagrammatic section taken substantially on the line 6-6 of Fig. 1 and illustrates the conveyor arrangement I employ, with only those parts shown which are directly associated with the conveyors.

Figs. 7, 8 and 9 are enlarged fragmentary sections taken on the lines 77, 8-8, and 9 9, respectively, of Fig. 6.

Referring now to Figs. 1 to 3 inclusive, it will be seen that I have therein illustrated a battery of furnaces A arranged to provide intermediate or central and end lon 'tudinal bays B, G, D and transverse bays F, etc., between furnaces.

A description of the furnace shown in section in Fig. 1 will suffice for all furnaces. The furnace, starting from the bottom, consists of an ash pit 7, located on the ash and pulverizer fioorS, and having door 9 for ash removal as by a vacuum system such as indicated at 10; a combustion chamber 11 above the ash pit and opening at the top into a boiler space 12 located in the boiler setting or chamber thereabove; the boiler elements, consist- .ing of the upper drums at, b, o and the lower drums (Z, (Z, with connecting banks of tubes 6, f, 9, 7t, inclined sharply toward the vertical; and the stack 13, located above the boiler space, and communicating therewith at the top of each of two opposite sides by means of the forked conduit-14. The banks of tubes are baffled in any preferred manner as indicated at 15.

The combustion chamber is fired from each of two opposite sides by means of a plurality of burners 16. coal being supplied thereto in a manner to be hereinafter described. The burners maybe of any desired construction. Pulverize'd'coal "or a mixture of coal and air is fed into the furnace preferably in a substantially vertical downward direction, additional air being supplied. through. the burner by induction and the balance needed for combustion through a group of openings 17 in the opposing front walls of the combustion chamber. The incoming streams are ignited by the radiant heat from the respective. front walls and the draught turns the streams back on themselves, the two upwardly moving portions of the fuel and flame streams uniting at the central portion of the combustion chamber. As the fuel particles become progressively gasified, the stream broadens because of increased volume, so as to practically fill the upper portions of the combustion chamber, which is of such size as to obtain substantially complete combustion therein. The hot gases of combustion sweep along the tubes and upwardly toward the center and then divide, part being drawn along the right hand tubes toward the draught outlet on that side of the boiler space and the remainder being drawn along the other tubes to the draught outlet on the opposite side.

The fuel and flame streams are preferably turned above the bottom of the combustion chamber to provide a cooling zone below the zone of combustion, through which the slag forming refuse not carried in suspension precipitates. In passing through this zone, such refuse cools below substantial slag forming tem erature. The ash deposit is dustlike or flake-like in character, susceptible of easy removal without shutting down.

From what has been described it will be seen that I take the fuel necessary to operate a furnace of given size and capacity at any given rate and divide it into streams admitted on opposite sides of the combustion chamber, as a result of which there is less coal per stream than would be otherwise the case, and thus, firstly, there is obtained a greater area of exposure for the fuel particles both to radiant heat and air; secondly, there is greater opportunity for each particle to be surrounded by air; thirdly, as the fuel particles begin to gasify and fresh quantities of oxygen bearing air are needed for the further combustion of the particles and for the combustion of the volumes of combustible gases released or distilled off, such fresh air is more readily available; and fourthly, the turning streams are reeiprocably subjected to one anothers radiant heat. As a result of these conditions, ignition takes place more quickly and combustion is completed in a shorter interval of time and more coal can be burned in a furnace of given size. Greater efiiciency is thus obtained and it is possible to greatly exceed the normal rating of a given sized furnace. In addition, a. greater pro ortion of the combustion chamber is made e ective and the hot gases can be more effectively delivered to the absorption surfaces for heat transfer.

Referring now to the manner of treating and handling the coal, it will be seen that I provide crushed coal bins 18 in the upper part of the central bay B, and the pulverizers 19 in the bottom thereof on the floor 8, the pipes 20 serving to feed the crushed coal to the pulverizers. Below the crushedcoal bins I arrange a pair of pulverized coal bins 522 for each furnaces burners,to which latterthe pulverized coal is supplied by the feeder mechanism 21 which may be of any preferred type. In the outer bays C and D I place other pulverized coal bins 22, arranged on the sides of the combustion chambers opposite the pulverized coal bins 22. The pulverized coal is taken from the pulverizers and elevated to the dust collectors or separators 24 by air, by means of the motor exhausters 25 and pipes 26. The pipes 23 are the air return pipes, carrying back the air after separation has been effected. The members 27 are additional dust collectors. The pulverized coal is discharged from the separators into the conveyors 28 and 29 running lengthwise of the transverse bays C, D, from which it is discharged to the pulverized coal bins 252* through suitable discharge openings 28" having suitable gates (not shown).

Pulverized coal is delivered to the bins '22 from the pairs of conveyors 28-29 by the pairs of conveyors 303l running longitudinally of the bay 13, delivery from conveyors 2829 to conveyors 3031 being made by cross conveyors 3233.

It will be seen from the foregoing that at each intersection of a transverse bay with the central longitudinal bay B there are four pulverizers, each of which normally supplies a respective pair of bins 9.2" and 22, the former being supplied from the separators thru the medium of conveyors 28 and 29 and the latter through the medium of conveyors 28-29, cross conveyors 3233, and conveyors 30-31. In case a furnace is shut down its pulverized coal bins become filled and thereafter the pulverized coal is conveyed to the next bin which is empty or only partially filled or which is feeding for it will readily be understood that when a bin becomes filled, the coal must necessarily be carried past by the conveyors.

All of the pairs of conveyors are oppositely acting, so that in case any pulverizer goes out of action temporarily, pulverized coal can be supplied from another pulverizer from an opposite direction by closing the gate or gates from the conveyor normally supplied by the inactive conveyor and open ing the gates from the other conveyor. Various delivery combinations are possible by this arrangement.

The whole supply system is thus very flexible and at the same time very simple and economical in spaceand also in power requirements.

Referring now to the modification shown in Figs. 4 and 5, this conforms in all substantial respects to what has previously been described, save that the pulverized coal bins of the central longitudinal bay are differently supplied. In this modification I have illustrated a battery of furnaces A arranged to provide longitudinal bays B G I) and transverse bays E F etc. ,between furnaces. The furnaces shown each include an ash pit 7 having door gr for removal of ashes as by vacuum system 10, the ash pit being located on the ash and pulverizer floor 8; a vconibustion chamber 11", opening into a boiler space 12 thereabove; the upper and lower drums of the boiler element being indicated by reference letters a, b, c and d and a stack 13 located above the boiler space.

Burners 16 are provided for the furnace which operate as described in connection with Figs. 1, 2 and 3.

For'treating and handling the coal I provide crushed coal bins 18 and pulverizers 19 on the floor 8 the pipes 20 serving to feed the crushed coal tothe pulverizers. Below the bins 18 I arrange pairs of coal bins22 for each respective set of burners and feeder mechanism. In the outer bays C and D I place other pulverized coal bins 22. The

pulverized coal is taken from the pulverizers and elevated to the dust collectors or separators 24. by air by means of the exhausters 25 and pipes 26. The pipes 23 are air return pipes. The pulverized coal is discharged from separators 24? into the conveyors 28 and 29 running lengthwise of the transverse bays C and D from which it is discharged to the pulverized coal bins 22 as described in connection with Figs. 1, Qand 3.

In this instance, however, there are two additional pulverizers 19 at the main intersections, each of which delivers to separators 24: located in the central bay and adapted to discharge into the respective pairs of conveyors 80 -31. Additional dust collectors are indicated by the reference character 27*.

It will be seen from the foregoing that bins 22 are supplied from the pulverizers 19, separators 24 and pairs of conveyors 28 and 29 while the bins 25% are supplied from the pulverizer 19", separators 24c and pairs of conveyors 3031.

The location of the separators at an upper level in position to discharge by gravityis also a simplification as it permits of the use of the air used in effecting separation as the means for elevating the pulverized coal, thus eliminating elevating conveyors.

No specific claim is made to the furnace structure per se, as claims directed thereto have been made part of the subject matter of a divisional application Serial No. 72;47, filed December 1, 1925.

\V'hat I claim is:

1. In a pulverized fuel burnlng system for power plants, the combination of a pair of furnaces spaced apart to provide a bay therebetween and including combustion chambers,

said furnaces occupying a substantial porizer below thepulverized coal bin, means'for delivering coal from the coal bin to the pulverizer, and means whereby coal may be delivered from the pulverizer to the pulverized coal bin.

2. In a pulverized fuel burning system, the combination of a pair of double fronted furnaces arranged to provide a central bay between furnaces and an outer bay at the other front of each furnace, each of said furnaces including a combustion chamber, a coal bin in the uper part of the central bay, a pulverized coal bin therebelow, feeder means for feeding pulverized coal from said pulverized coal bin to one of said combustion cham bars, a pulverizer below said pulverized coal bin, conveyor means leading from the coal bin to. the pulverizer, a pulverized coal bin in each outer bay, means for supplying pulverized coal thereto from the pulverizer, an a feeder means for supplying pulverized coal from said last mentioned pulverized coal bins to a combustion chamber.

3. In a pulverized fuel burning system, the combination of a pair of double fronted furnaces, arranged to provide a central bay between furnaces and an outer bay at the other front of each furnace, each of said furnaces including a combustion chamber,

a coal bin in the upper part of the central bay, a pulverized coal bin therebelow, feeder means for feeding pulverized coal from said pulverized coal bin to one of said combustion chambers, a pulvcrizer below said pulverized coal bin, conveyor means leading from the coal bin to the pulverizer, a pulverized coal bin in each outer bay, a feeder connection from each thereof to a combustion chamber, separator means, a connection between the pulverizer and separator means, and means for supplying pulverized coal from the separator to the various pulverized coal bins.

4. In a pulverized fuel burning system, the combination of a pair of double fronted furnaces arranged to provide a central bay between furnaces and an outer bay at the other front of each furnace, each of said furnaces including a combustion chamber, a coal bin in the upper part of the central bay, a pulverized coal bin therebelow, feeder means for feeding pulverized coal from said pulverized coal bin to one of said combustion chambers, a pulverizer below said pulverized coal bin, conveyor means leading from the coal bin to the pulverizer, a pulverized coal bin in each outer bay, a separator in each outer bay, means for supplying pulverized coal thereto from the pulverizer, and conveyor mechanism for supplying pulverized coal to the various pulverized coal bins from the separators.

5. In a powdered fuel combustion system, the combination of a furnace, at pulverized fuel bunker, means for feeding coal from said hunker to the furnace, a green coal bunker located above the level of said powdered fuel bunker, and coal treating, apparatus through'which the coal is fed from said green coal bunker to said pulverized fuel bunker, said apparatus including treating units to which the coal is fed by gravity from said green coal bunker.

In testimony whereof, I have hereunto signed my name.

VIRGINIUS Z. OARAORISTI.

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