US1778721A - Apparatus for generating steam - Google Patents

Description

I E. P. MORITZ APPARATUS FOR GENERATING STEAM Oct. 21, 1930.

Filed Feb. '7, 1927 I INVENYV'IOR KU'ORNEYJ" TED OFFICE i ED'WIN P. URTTZ, 0F YORK, It. TI, ASSIGNOR T0 INTERNATIONAL COMBUSTION GIENTSECRING CORPORATION, @ll NEW YORK, N. Y., A CORPORATION,OF DELAWARE ill till! could not fill arr ATUS FOR GENERATING STEAM Application filed February 7, 1927. Serial No. 166,289.

This invention relates to the art of generating steam, and to improvements inoperation, especially in so far as combustionis concerned. I 1

@ne of the primary objects of this invention istoefiectively burn ,blast furnace gas I or other low grade gases in a radiant heat boiler. I

Another object of the invention has to do with improvements in efiecting combustion at times of peak load in a radiant heat boiler of a size such that it can meet normaldemands while burning the fuel efficiently, but which in'the absence of such improvements, peak demands with efficiency. More specific objects will appear hereinafter. v

How the foregoing, together with such othor objects and advantages as may hereinafter appear, or are incident to my invention, are realized, is illustrated in preferred form in the accompanying drawing, wherein The figure is a sectional elevation of a boilor furnace embodying the invention. 7

Referring now to the drawing, the reference character A denotes the combustion chamber of the furnace which is largely defined by a front water wall 2., side water walls 3, and a rear water wall t. These'water walls are composed of upright tubes having longitudinally extending fins welded or otherwise secured thereto, the fins and tubes cooperating to form a practically continuousmetallic wall The top of the combustion space is defined by the row of tubes 5 and the refractories 6, and the bottom is defined by a bank of tubes 7, the tubes of which are laterally spaced apart sulficiently to permit the free passage of the waste gaseous products of combustion and of the descending refuse and fuel, in a manner well known in the art.

The tubes of the rear wall 4 have their upper and lower ends respectively connected into upper and lower drums 8 and 9." The tubes of the side walls 3 have their upperand lower ends, respectively, connected into headers 10 and ll,in turn respectively connected into the drums 8 and 9.- The tubes of the front wall 2 have their lower ends con admit gas, pulverized fuel and air nected into a drum 12, the drum 9 by the bank their upper ends connected into a drum or header 13 in turn connected to the drum 8 bv the roof tubes 5.

Fuel is preferably admitted in the upper portion of the combustion chamber A at the four corners thereof by means of the burners indicated as a whole by the reference numera1 14. These burners each comprise a pluin turn connected to of tubes 7 and have A bit rality of gas nozzles 15 and a plurality of pulverized fuel nozzles 16, the latter being preferably located between the former. Blast furnace gas is supplied to the gas nozzles 15 from the gas main 1'2 and pulverized coal is supplied to the nozzles 16 from the distributors 18. Combustion air is supplied around the burners by means of the channel 19 leading from the air preheater B, with which is associated a forced draft fan B. Thus, it Will be seen that the burners are adapted to into the furnace in a manner to produce turbulent mixing. ln this connection, it is to be noted that by employing valves 38 and 39 controlling the admission of the ized fuel respectively, either may be; burned by shutting off the other. The air supply is common to both.

Bylocating the burners at the corners a vortical motion of thefuel and flame stream is set up, the axis of: the vortex being longitudinal of the boiler furnace. The fuel and flame'stream sweeps over the tubes which is ofimportance with low grade gas, as there is thus secured transmission of heat both by radiation and by convection--v'vhich is especially desirable because of the flame of low grade gas does not have a high capacity for transmitting heat by radiation.

The pulverized coal admitted with the gas will add luminosity to the flame, and thus increase its radiating capacity. Therefore, medium, and especially at high, ratings, .l burn pulverized coal with the gas securing an increase in the transmission of heat by radiation, as well as by convection to give the increased capacity desired, and which other wise could not be obtained in a radiant heat gas and the pulver- "ill till

boiler by merely increasing quantity or gas admitted.

The evaporating area of the boiler is such as to supply normal demands when operating efficiently from the standpoint of combustion to which end the air admission at the burners and at 20 is adequate to efficiently burn the quantities of fuel admitted to supply normal demands. To make such a boiler supply peak of air in the space defined by the boiler to increase the temperature and, therefore, the rate of heat transmission.

Under these conditions, some combustibles tend to pass out with the waste products of combustion, which combustibles I propose to burn in a secondary chamber C located beyond the bank of tubes 7, into which is introduced the additional amount of air required for combustion.

As a means for introducing this secondary 7' air, I have provided a metallic air box or over the superheater 26 which channel 21 covered by refractories 22, the front wall of which has a plurality of air ports 23 controlled by damper 37 for admitting air into the chamber C in a direction toward the front wall of the furnace. In this instance, preheated air is led to the channel 21 by means of the branch conduit 24 of the air channel 19. In this connection, is pointed out that the secondary air, flowing as it does in a direction substantially opposite to that of the path of flow of the products of combustion, tends to maintain the products of combustion away from the refractories of the channel 21 so that they are protected as against scouring.

The waste gasesfrom the chamber G pass rearwardly and upwardly over the bank of economizer tubes 25, the upper and lower ends of which are connected into the upper and lower drums 8 and 9, respectively, and is located amongst the economizer tubes. It will be noted that the arrangement is such that the economizer tubes become the downcomers of the boiler. I

Reverting now to the air channel 21, it will be observed that the air is admitted to the chamber C in such mannerthat thorough mixing takes place in the fore part of such chamberthus ensuring completion of combustion before the economizer and superheater are reached.

The rear pass of the boiler in which the economizer section and superheater is located is defined by a rear refractory wall 27 forwardly offset at 28 and having vertically spaced transversely extending projections 29, and by the refractory sheathing 30 having a projection 31, similar to the projections 29,

located at an elevation intermediate the elevations of the projections 29. By means of these bafiles, the products are forced to take a more or less tortuous path through the econdemands, I operate it with a deficiency omizer section and superheater unit until they finally emerge into the breeching 32 from which they are carried to the stack 33 by the action of the induced draft fan 34:.

The location in the ofltalre of the conomizer section,- the superheater and the air heater ensures the absorption of heat from the waste gases whereby the final exit temperatures are kept within allowable limits.

Owing to the character of the fuel being burned I have provided an ash pit 35 of considerable size. A plurality of gate controlled openings 36 are provided in the bottom of the ash pit for removing from time to time the refuse and ash collecting therein. The gates are normally closed when the furnace is functioning as diagrammatically indicated in the drawing.

From the foregoing it will be seen that the arrangement of the furnace and associated parts is such that considerably less floor space and head room is required than heretofore. The arrangement is well adapted to the grouping of a plurality of boiler units in a small area.

In comparison to other arrangements for the burning of low grade fuels, such as blast furnace gas, a relatively high ca acity for a relatively small sized boiler is o tained.

It claim 1. In combination, a tubular boiler furnace comprising a plurality of vertically extending water tubes defining the rear, front and side walls of the combustion chamber of the furnace, means for introducting and lnirning pulverized coal and gas in said combustion chamber, a secondary combustion chamber. an air channel below the rear wall of said first combustion chamber, and means associated with said channel for introducing an ad ditional supply of air into said secondary combustion chamber and economizer elements subject to the heat of said secondary combustion and associated with the boiler-furnace so that the heat absorbed is utilized in the generation of the steam.

2. In combination, a tubular boiler furnace comprising a plurality of vertically-extending water tubes defining the major portion of the walls of the combustion chamber of the furnace, means for introducing pulverized, fuel and gasinto said combustion chamber, means for supplying combustion air, a cross drum into which the lower ends of the rear water tubes are connected, an air channel disposed beneath said cross drum, means associated with said channel for introducing a regulated amount of air into the furnace below the combustion chamber thereof for promoting complete secondary combustion of the fuel, and economizer elements subject to the heat of said secondary combustion and associated with the boiler-furnace so that the heat absorbed is utilized in the generation of the steam.

'subject'to the gaseous products of combustion in said offtake, said elements being associated with the boiler-furnace so that the heat absorbed thereby is utilized in the generation of the steam. v

In testimony whereof I have hereunto signed my name.

. EDWIN P. MORITZ.

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