US2204351A - Method of firing steam generators - Google Patents

Description

June 11, 1940. M. FmscH 2,204,351

11m-Hon oF FIRINGSTEAM GENERATORS I Filed Nov. 19,` 1936 3 Sheets-Sheet A1 June 11, 1940.4 M, FR|$H 2,204,351

' uETHon oF FIRING s'rEAu GENERATORS Filed Nov. 19, 1936 3 .Sheets-Sheet 3 psichica Jucc 11, 1940 'ME'rno-n oF-FIRING PATENT ,o1-FICE STEAM GENEnA'rons Martin Frisch, Cranford, N. J., signor Ato Footer Y Wheeler Corporation, poration of New `York Application November 19, 1936, scric1 New York, N. Y., a corv 9 claims. (o1. 12a-333)A AThis invention relates to steam generators and more particularly pertains to methods of firing steam generators and the'like. n

The invention providesa novel method of flring steam generators and the like which results in complete utilization of the generator furnace volumeirrespective lof the load on theigenerator;

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provides maximum ash deposition in the furnace or'furnaces, and attains more complete and more rapid combustion ofthe fuel employed than has heretofore' been attained in the art.

The invention will be understood from the fol-V lowing description when considered in connection with the accompanying drawings forming a part thereof in which:

Fig. l is a transverse vertical sectional view of steam generating apparatus arranged for carrying out the method of the present invention;

Fig. 2 is a horizontal sectional view taken sub-k in the upper portion offront wall I of each stantially on line 2-2 of Fig. l; and

Fig.- 3 .is a side elevationalview of the apparatus with certain parts insection.

Like characters of reference designate the v same or similar parts in the several views.

Although the invention is disclosed in connection with, or a's being carried out in, a vertical straight tube type of steamrgenerator having two furnaces flanking the steam generating sectionv of the generator,-it will be understood that the invention is capable of being carried out in other types of steam generators and in generators hav- Aing'only a single furnace or having more than two furnaces.

Referring tothe drawings, the steam generator illustratedv is enclosed in a` casing having la front wall III, a rear wall II and sidewallsl|2 and I3. 'I'he steam generating -section I l is disposed intermediate two rectangular furnaces I5 and I6.

' through a steam pipe 28 toa superheater. In'

through la.' plurality of steam risersv 26 withV a` steam drum 21, from which steam is conducted addition to the relatively small tubes I1,` the steam generating section includes a plurality of i rows of Vsomewhat larger straight vertically` disposed tubes 29.l A superheater consisting of a plurality of small loop tubes 30 is disposed at the .inlet end of `the steam generating section Il. The steam generatingsection is separated at its sides from the furnaces I5 and |6 by means ofthe walls 3| and'32 which may be of any suitable form and if desired, may consist of a plurality. of armor blocks secured to water wall tubes. Slag Ascreens 33 and 34 are lisposed between the forward ends of walls 3| and 32 respectively and the front wall III of the-boiler casing. All of the walls of the furnaces I5 and I 6 are water cooled by waterwall tubes 35 and 38 respectively. If desired however, for low capacity installations,vthe firing Wall and the rear Wall of each of the furnaces may be installed without Water cooling.

In the form of the invention illustrated, the furnaces are fired by a fuel burner 31 disposed furnace and by a burner 38 disposed in the lower portion of the front wall of each furnace. These burners are arranged to discharge jets of fuel and primary air through the spaces between the water wall tubes 35 -and 36 and may be of the form disclosed andv claimed in my copending application Serial No. 444,906, led April 17, 1930. Seconda,-

ary air is supplied to the burners through air ducts 39 which deliver. the air to air casings 40 disposed at the outer side of 4the front wall 4III of each of the furnaces. Secondary air from the casings lll flows through a pluralityof air passages II disposed above each of the fuel jets. of

the burners 31 and 38 and simultaneouslyv through a plurality of air passages 42 disposed below each of the fuel jets of these burners. The volume and velocity ofthe secondary air discharged through these air passages may be controlled by suitable means such as dampers or the like so that the resulting streams of gases or products of combustion may be directed horizontally,v

zontal path from the fr ont end of each furnace Kto the rearend thereof and the stream of products of combustion from the lower burner 38 in each furnace simultaneously flows in a horizontal path from the front end of the furnace through the lower portion thereof tothe rear end of the furnace. Adjacent the rear end of each furnace the upper stream turns downwardly and the lower stream turns upwardly and the two streams impinge upon and mix with each other as they turn through an angle of approximately 180. The resulting stream ows toward the front end of each furnace through the central portion of leach furnace intermediate the upper and lower streams. When these resulting streams rea-ch the front end of each furnace, each turns through an angle of 90 in`a horizontal plane and passes over the slag screen disposed at the outlet of each furnace and enters the chamber 45 disposed at'the forward end of steam generating section I4 a-nd between the furnaces l5 and i6. In this chamber the two streams of products of combustion issuing from the furnaces impinge upon and mix with each other and thereafter change their direction of ow through another angle of 90 in a horizontal direction and ow over the superheater 3l] and pass in a single pass through the steam generating section i4 over the tubes 29 and l1 and pass out through flue 46 at the front end of the steam generating section and flow downwardly therein through the return bend portion d1 and upwardly through 'the vertically disposed portion 48 into an induced dra-ft fan 49 and thereafter into a stack 50. An economizer may be installed in the return bend section 41 of the ue and an air heater 5| may be employed in the section 48. Air is forced through the air heater by a forced draft fan 52.

With this method of firing, it will be .perceived that all, or substantially all, of the furnace Volume of each furnace is fully utilized by reason of the fact that streams of products of combustion are continuously owing through the upper and lower portions of each furnace in the same direction and through the central portion of each furnace in the opposite direction. "Additionally, at the point or zone in each furnace where the streams of 'products of combustion turn to begin their return toward the front end thereof, intensive mixing occurs which results in the speeding up of combustion to a maximum and the reduction of stratification' to a minimum. Moreover, it Will be perceived that each of the streams of products of combustion is forced to abruptly change its direction of flow twice prior to entering the steam generating section and each of these changes in ow direction is through an angle of approximately 180, the first turn being in a vertical plane and the second turn in a horizontal plane. With these abrupt changes in flow direction a larger proportion of suspended ash in the streams will be precipitated within the furnace than has been accomplished in the art heretofore.

'I'he method of the present invention may be carried out in apparatus other than the specific form of the steam generator herein disclosed.

Additionally, it will be understood that variations may be made in the method and in the several steps thereof without transcendirrg the principles of the invention. For example, a vsingle stream of products of combustion may be produced in each furnace which will fiow practically through, the entire furnace voliune prior to entering the steam generating section, substantially in the manner in which one of the streams ows in lthe form of the invention disclosed. In` this event, there will be no mixing of separate streams in the furnaces, as in the form disclosed. 'I'he single stream of products of combustion will be produced, preferably, by a burner, or tier of burners, so disposed in the lower portion of each furnace that'the ame stream or the stream of products of combustion will pass to the rear of the furnace in the lower part thereof, and after turning the stream returns through the central and upper portions of each furnace. Other variations will occur tothose skilled in the art. Accordingly, no intention is entertained to limit the invention except by the scope of the appendedclaims.

What is claimed is:

1. The method of firing a steam generator which comprises producing a plurality-of separate, vertically disposed, substantially parallel streams of products of combustion in a furnace, causing said streams to abruptly change their directions of fiow in a vertical plane andvto impinge upon and mix with each other and to flow through the furnace in a direction substantially parallel to the separate streams, and causing the resulting stream to abruptly change its direction of ow prior to flowing in heat' exchange rela' parallel to the separate streams, and causing the resulting stream to abruptly change its direction of ow in a substantially horizontal plane prior to owing in heat exchangel relationship with the steam generating surface of the generator.

3. 'I'he method of ring a steam generator which comprises producing separate streams of products of combustion in the upper and lower portions respectively of a furnace connected with the steam generating section of the generator, causing said streams to ow through thefurnace in substantially parallel relationship, causing said streams to abruptly change their directions of ow toward each other and to impinge upon and mix with each other, causing the resulting stream to flow through the furnace between said separate streams inra direction opposite thereto and causing the resulting stream to abruptly change its direction of flow prior to flowing into heat exchange relationship with the steam generating surface of the generator.

4. The method of flring a steam generator which comprises producing separate streams of products of combustion in the upper and lower portions respectively of an end portion of a furnace connected with the steam generating section'of the generator, causing said streams to ow through the furnace in substantially parallel relationship, causing said streams -to abruptly change their directions of ow toward each other and to impinge upon and mix with each other, causing the resulting stream to flow through the furnace between said separate streams in a direction opposite thereto and causing the resulting stream to abruptly change its direction of ow prior to owing into heat exchange relationship with the steam generating surface of the generator.

5. The method of vfiring a steam generator which comprises producing separate streams of products of combustion the upper and lower portions respectively of an end portion of a. fur- 4each furnace to flow nace connected with the steam generating section of the generator, causing said streams to flow through the furnace in substantially parallel relationship, ruptly change their directions of flow toward each other and to impinge upon and mix with each other,v causing the resulting stream to iiow through the furnace between said separate streams in a direction opposite thereto and causing the resulting` stream to abruptly change its 4direction of flow in a substantially horizontal plane prior to flowing into heat exchange relationship with the steam generating surface of the generator.

6. 'Ihe method of tiring a steam generator having a steam generating section connected toa plurality of laterally disposed furnaces which comprises producing a stream of products of combustion in each furnace, causing the stream in each furnace to flow successivelyin opposite directions through different, vertically spaced portions thereof and to abruptly change its direction of flow in its passage therethrough, and causing each stream to abruptly change its direction of flow prior to passing into heat exchange relationship with the steam generating section.

7. The method of firing a steamgenerator having a steam generating section connected to a plurality of laterally disposed furnaces which comprises producing a stream of products of combustion in each successively through different, vertically disposed portions thereof and to abruptly change its direction of flowxin its passage therethrough and causing each stream to abruptly change its direction of flow and to impinge upon and mix with the stream from ancausing said streams to abfurnace, causing the stream inv other furnace prior to passing into heat exchange relationship' with the steam generating section.

8. The method of firing a steam generator having a steam generating section connected to a plurality of laterally disposed furnaces which comprisesv producing a stream of products of combustion in each furnace, causing the stream in each furnace to flow successively through different portions thereof and to abruptly change its direction 'of flow in its passage therethrough, and causing each stream to abruptly`change its direction of flow and to impinge upon and mix with the stream from another furnace prior to passing' into heat exchange relationship with the steam generating section.

9. The method of ring a steam generator having a steam generating section anda furnace disposed at each side thereof and connected therewith which comprises producing separate streams of products of combustion at one end of each furnace, one stream adjacent the upper portion of each furnace and another stream adjacent fthe I lower portion, causing the streamslin each furnace to now therethrough invsubstantiallyvparallel relationship, to abruptly change their directions of `flow toward each other and to impinge upon and mix with each other, causing the resulting stream in each furnace to flow therethrough between thel upper and lower streams and in the opposite direction, causing the resulting stream in each furnace to abruptly change its direction of flow and to impinge upon and mix with the stream fromlthe other furnace and causing said mixed streams to flow in one pass through the steam generating section..

' FRISCH.

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