US2800888A

US2800888A - Fuel burning apparatus

Info

Publication number: US2800888A
Application number: US401158A
Authority: US
Inventors: Earle C Miller; Craig Ollison
Original assignee: Riley Power Inc
Current assignee: Riley Power Inc
Priority date: 1953-12-30
Filing date: 1953-12-30
Publication date: 1957-07-30
Anticipated expiration: 1974-07-30

Description

July 30, 1957 E. c. MILLER ErAL 2,800,888

FUEL BURNING APPARATUS.

2 Sheets-Sheet l Filed Dec. 30, 1953 [ARLE C. M/LLER OL L/.so/v CRA/q mmm/MW ATTORNEY July 30, 1957 E, c, MILLER ETAL 2,800,888

FUEL BURNING APPARATUS 2 Sheets-Sheet 2 Filed Deo. 30, 1953 E mea FWalmmm Mc .N O L E0 www ATTORNEY United States Patent FUEL BURNING APPARATUS Earle C. Miller and llison Craig, Worcester, Mass., as-

sgnors to Riley Stoker Corporation, Worcester', Mass., a corporation of Massachusetts Application December 30, 1953, Serial No. 401,158

2 Claims. (Cl. 122-479) This invention relates to fuel burning apparatus and more particularly to apparatus arranged to be used with a steam generating unit.

In the past it has been a common practice to provide for the control of superheat in a steam generating unit by controlling the angle to the horizontal of the flame produced by the burners in the furnace serving a boiler. By the use of a directional flame burner it is possible to provide for a considerable range of superheat temperature by adjustment of the flame from an extreme downward position in the furnace to an extreme upward position in the furnace. The selection of various positions of the directional flame burner to provide a desired superheat temperature is accompanied by certain disadvantages. One of these disadvantages is that the temperature in the lower portion of the furnace is changed at the same time that the angle of the burner is changed and this results in varying degrees of slagging. It can be understood that, when the burner is directed in an extreme upward position, there is a tendency to set up conditions in the lower portion of the furnace which do not permit ease of ow of slag. At the same time, a definite position of a burner in a furnace may be selected to obtain complete or almost complete combustion. However, when the ame position is changed to control superheat, the degree of combustion may also change, resulting in excessive fiyash, particularly in the case of pulverized coal. By use of the present invention it is possible to obviate some of these diicultics while at the same time obtaining a desirable degree of control of superheat.

It is therefore an outstanding object of the present invention to provide an apparatus for burning fuel which will permit a wide range of control of superheat and at the same time bring about the optimum amount of slagging in the lower portion of the furnace.

It is another object of the present invention to provide a fuel burning apparatus in which the waste of unburned carbon in yash is minimized.

A still further object of the present invention is the provision of a fuel burning apparatus which provides for the control of superheat and at the same time permits the complete burning out of carbon from yash and the maintenance of optimum slagging conditions.

A still further object of this invention'is the provision of fuel burning apparatus for maintaining a slag pool in an optimum condition and for the disposal of yash along with the slag.

Another object of the invention is the provision of apparatus for use in the burning of pulverized coal in a furnace of the slag-pool type, wherein provision is made for the control of superheat and the maintenance of optimum slagging conditions as well as complete disposal of yash.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself as to its objects and advantages, the mode of its operation,

ICC

and the manner of its organization may be better understood by referring to the accompanying description taken in connection with the accompanying drawings forming a part thereof, in which Figure l is a longitudinal sectional view of a steam generating unit constructed after the teaching of the present invention, and

Figure 2 is an enlarged longitudinal view of a burner embodying the principles of the invention.

Like reference characters denote similar parts in the several figures of the drawings.

Referring first to Figure l, wherein is best shown the general aspects of the invention, a steam generating unit, designated generally by the reference character 10, is shown as comprising a boiler 11 and a furnace 12. The furnace 12 is made up of a forward wall 13, a rear Wall 14, and side walls 15 dening a combustion chamber 16. A refractory basin 17 forms the lower portion of the furnace in which a slag pool may be maintained. Suitable provision, not shown, is provided for tapping the slag pool in the usual manner. The boiler 11 comprises in the usual way a steam-and-water-drum 18, a mud drum 19, downcomer tubes 20, and steaming tubes 21. A convection superheater 22 is connected on its inlet end to the steam-and-water-drum 18, and at its outlet end to a header 23 from which it is carried to turbines not shown. Below the tube banks of the boiler is situated a yash-collecting hopper 24. A breaching 25 of the usual type is connected to an induced draft fan 26 to which is also connected a cyclone-type'yash separator 27 for cleaning the gases before projecting them into a chimney, not shown. A conduit 28 is connected to the lower portion of the hopper 24, while a conduit 29 extends downwardly from the tlyash collector 27

Conduits

28 and 29 are connected to a yash conduit 30 in which resides an ejector 31 provided with pressure air by a fan 32. In the front wall 13 of the furnace l2 is situated a burner 33 which will be described more fully hereinafter. The burner 33 is provided with heated secondary air from the air heater 25. It is also provided with flyash through the conduit 30. A coal bunker 34 sends coal down a chute 35 and through a feeder 36 into a coal pulverizer 37. The outlet of the coal pulverizer is connected to the burner through a conduit 38. As is evident in the drawings, the burner 33 comprises a set of upper directing vanes 39 and a set of lower directing vanes 40. A temperature indicating means 41 resides in the superheated steam header 23 and is connected by a lead 42 to a controller 43. The controller 43 in turn sends a signal through leads 44 to a motor 45 which actuates the upper directing vanes 39 in a manner which will be described more fully hereinafter. This superheat control means may be either electrical or hydraulic.

Referring next to Figure 2 wherein are best Ishown the details of the burner 33, it can be seen that the upper directing vanes 39 and the lower directing vanes 40 are independently adjustable and controllable. All the vanes, however, are of an elongated, diamond-shaped crosssection and are mounted on a horizontal pivot 46 passing generally through the center of gravity of the cross-sec# tion. The upper directing vanes 39 are connected by links 47 to an actuating shaft 48 which is in turn connected to the motor 45 for the actuation thereof. The lower directing vanes 40 are connected by links 49 to an actuating shaft 50, the outer extremity of which is threaded at 51 and is provided with a hand wheel 52. The threaded portion 51 passes through a fixed nut 53, whereby the actuating shaft 50 may be moved longitudinally, thus changing the angularity of the directing vanes 40. The vanes are enclosed by a housing 54 which flares outwardly toward the furnace. An ignition torch 55 of the usualtype is provided Ycentrally of the burner. On

either side ofthe torchand horizontally thereof isa large 57 connected to the flyash conduit Si). The nozzle openingv is directed-toward the vanes; thatis to say, 'downstream of theilow-of fuel and air. Y

TheV outer portion of the burner comprises a fuel tube 58 which is connected at itsrouter end to 'a fuel distributing head 59 whose inlet-is'connectedj to thepulverized coal' conduit @3S connectedtothe-pulverizer37. Theusual adjustablevanes 6l) are provided for controlling'coal'distrihution Within the tube'SS. TheLinner vend of the tube 58' is provi'ded'with` fuelgspreading vanes 6l in the usual way. `Surrounding the tube 58 is a :secondary air housing 62'whose entranceisprovided with adjustable vanes 63 for controlling tl'le'entrance of hot sccondaryair originating in the ',air'heater 25. The Yvaries 63 Vare adjustable through a linkage-mechanism 64 and a hand crank 65. Alsuitableair directing tube 66 and mixing vanes 67 are also' provided.

The operationof the apparatus will now be understood in view of the above description. Feedwater is introduced nearthe steam-and-water-drum 18, passes downwardly through the downcomer tubes 20, and, after circulating through the tubes of the boiler, passes upwardly into the space over theY water in the steam-and-water-drum and passesl intothe vsuperheater 422. The superheated steam leaves the superheater, enters the header 23, and passes eventually to the turbines. The temperature of the superheated steam is measured bythe indicator 4l and a proportionate'signal is transmitted through the lead 42 to the `heated by' the air heater 25 passes Vto the burner 33 by means of the'housing 62. VFuel leaving the bunker 34 passes downwardly through the chute 35 Vthrough Lthe feeder 36 and is reduced to a powder in the pulverizer 37. The'pulverized coal 'leaves through the conduit 38 and enters .the distributinghead 59. Pulverized coal and air are mixed by the-vanes'67 and pass into the burner housing 54. The mixed fuel and air is split by the central dividing vane S6 into an upper and a lower component. The direction of the flame produced by the burning of the upper component is controlled by the upper directing vanes 39, Whiletheiarne produced by the lower component is controlled by the lower directing vanes 40. As the operation of thetstearn. generating unit progresses, the controller Y43 will receive signals from the indicator 41 indicative of the superheat temperature being obtained and willV adjust the vanes '39 toproducey a 'change in superheat temperature, if such be necessary. Slag forming on the walls of the combustion chamber 16 will pass downwardlyy to the refractory basin`17 and will collect, forming a slag pool. In order Vthat this slag pool may remain inthe Vproper viscosity for tapping, the .operator is able to direct the ameformed by'the vanes 'dil in the proper direction to maintain the desired slag condition. He does this by actuation of the wheelf52, thereby changing the angularity of the vanes 4G through the threaded portion 5l, the actuat-Y ing shaft 50, and the links 49. VAt the same time yash originating in the hopper 24 and the separator 27 falls' down the

respective conduits

28 and 29 into the flyash conduit 30. VThe yash is propelled under the action of the fan 32 and the ejector 31 and passes into the burner housing 54 through the nozzle 57. Since the nozzle is situated in the lower portion of the burner, the flyash will take the direction dictated by the'vanes'40fand-willfreside in the lower llameV controlled by the Vanes 40 and will be projected in a downward direction toward the slag pool. The carbon remaining in the flyash will be completely burned out in the hot llame and the remaining yash will be caught in the sticky slagpool. The yash will thus be j completely burned out and disposed of.

controller 43. Gas originating in the combustion chamber Y `i6 passesrthrough the furnace ove'r the steaming tubes,

Y also prevent the flyash striking the slag pool.

As is evident from the above, thereeare' distinct advantages in mixing the ilyash, coal, Yande-air in the burner and'.

air high in oxygen, thus promoting complete combustion of the iiyash.

While certain novel features ofV theinventifon have beenV shown an'd described and are pointed out inthe annexed claims, it will be understood that various omissions, sub-V stitutions, and changes in the forms and details of the device-illustrated and in its operation may be made by those skilled in the art ywithout departing from the spirit of thev invention. e

Having thus described our invention, whatwe claim as new and desire to secure by LettersPatent is:

1.7A fuel burningapparatus comprising a pulverized coal red steam generating Aunit having a convection superheater and a refractory slag-basin, a burner havingV provision for directing aV portion of the flame in'ran upward direction and controlling'the Aangle to the horizontal occupied by the said portion, the burner also having a provision locatedjust above the basin for directing the remaining portion of the arne in a downward direction into the basinand controlling the angle to the horizontal occupied by the said remaining portion, means Vfor-injectinglllyash into thes'aid remaining portion Aonly of the llame, `and means responsive to the temperature ofthe steam leaving the superheater to actuate the burner to change the angle of the upwardly directed portion of the flame to cause the said temperature t-o change to a desired level.

2. A fuel burning apparatus comprising a pulverized coal-tired steam generated unit having a convection superheater and refractory slag basin, a burner having provision including horizontally-.pivoted vanes for directing a portion of the ilame in an upward direction and controlling the angle to the horizontal `occupied by the said'portion, the boiler also having a provision including horizontallypivoted vanes located just above the basin for directing the remaining portion of the llame in a downward direction into the basin and controlling the angle'to the horizontal occupied by the said remaining portion, meansfor injecting tlyash into the said remaining portion only of the llame, and means responsive to the temperature of the steam leaving the( superheaterYto-actuate the burner to change'the angle of the upwardly-directed portion of the ame to cause the` said temperature to change to a desired level.

References Cited in the tileofV this vpatent UNITED. STATES PATENTS ,Frisch Jan. 21, 1941