US3007458A

US3007458A - Vapor generator

Info

Publication number: US3007458A
Application number: US693196A
Authority: US
Inventors: Leon Kurt; Ossig Walter
Original assignee: Babcock and Wilcox Ltd
Current assignee: Babcock International Ltd
Priority date: 1956-11-08
Filing date: 1957-10-29
Publication date: 1961-11-07
Anticipated expiration: 1978-11-07

Description

K. LEON ET AL VAPOR GENERATOR Nov. 7, 1961 3 Sheets-Sheet 1 Filed Oct. 29, 1957 II I l FIG.4

31 37 7 29 34 36 2e 30 as 35 l l I l r INVENTORS Kur'r Leon BY We Hear Ossig ATTORNEY Nov. 7, 1961 K. LEON ErAL 3,007,458.

VAPOR GENERATOR Filed Oct. 29, 1957 3 Sheets-Sheet 2 ill ATTORNEY NOV. 7, 1961 LEON ETAL 3,007,458

' VAPOR GENERATOR Filed Oct. 29, 1957 3 Sheets-Sheet 3 INVENTORS Ku r1 Leon BY V Waher Ossig ATTORNEY United States Patent M 3,007,458 VAPOR GENERATOR Kurt Leon, Mulheim (Ruhr), and Walter Ossig, Oberhausen, Rhineland, Germany, assignors to Babcock & Wilcox Limited, London, England, a British company Filed Oct. 29, 1957, Ser. No. 693,196 Claims priority, applicationv Germany Nov. 8, 1956 11 Claims. (Cl. 122235) This invention relates to a fluid heating apparatus, and more particularly to a pulverized coal-fired, forced flow vapor generator having a furnace defined by fluid cooled wall tubes and having fluid cooled nozzles of burner means, arranged therein. Specifically the present invention is directed to the utilization of the continuous fluid cooling wall tubes adjacent the nozzles for cooling the same by having an intermediate portion thereof coiled about the burner nozzle in intimate contact therewith.

Pulverized coal burner nozzles customarily utilized for firing vapor generators of the character described have been previously cooled by either air or water. However,

air cooled burner nozzles, water cooling of the nozzles A was more often resorted to. However, as water cooling has the advantage of a decidedly more active cooling effect, the prior known constructions by which water cooling was accomplished and the operations thereof were relatively complicated in that a separate cooling water circuit was oftentimes required which produced definite heat losses. These losses include the heat absorbed in the separate fluid circuit which is not available for useful steam generation and the path of warm cooling water. This loss has been minimized by recirculation of the warm cooling water into the feed water supply. An additional loss is caused by the supplementary power requirements of a pump for circulating the water in the separate nozzle cooling circuit. Heretofore, the nozzle cooling water line had also been connected to a first stageof a feed pump, in which case several pumps were installed. This was necessary because the cooling effect must also be guaranteed at partial loads, thus the same circuit must also'be tied into the emergency feed, which produced a still further complication of the installation.

An object of this invention is to overcome the foregoing disadvantages by utilizing the continuous fluid flow tubes of a forced flow boiler for burner cooling.

of a single tube group lining adjacent corner burner walls,

Another object of this invention resides in a furnace I having a novel fluid cooled wall tube arrangement in which portions of the wall tubes are utilized for fluid cooling 3. burner nozzle disposed in the furnace walls.

Still another object of this invention resides in interchanging the relative position of the wall tubes with respect to one anotherto more effectively equalize the heat absorbed by any given tube and combining therewith effective cooling of a burner nozzle in a relatively simple and positive manner. I

The objects and advantages of this invention are attained by utilizing the continuous flow of a forced flow boiler for burner cooling. The burner means are cooled by portions of the wall tubes which are particularly formed in the vicinity of the burner and which are adapted to cool individual nozzles of the burner means. Accordingly, the arrangement of this invention results in 3,007,458 Patented Nov. 7, 1961 an effective and simplified cooling of the burner nozzles in that each nozzle is surrounded by a helically coiled portion of a single cooling tube, the extension of which forms the customary heat absorbing surfaces outside of the burner region together with other wall cooling tubes.

5 In furnaces arranged with two adjacent burner means,

in the group form secondary nozzle cooling tubes which more or less frame the nozzles. The extensions of these tubes are arranged in a serpentine fashion between the adjacent burner means and serve to cool the intermediate portion ofthe wall therebetween. Where the burner -means are disposed at the corners, the serpentine arranged tubes cool the included wall. According to this invention the tubes in their passage from one burner means to the other interchange their relative position so that the primary cooling tube of one burner means becomes the secondary cooling tubes of the other burner means and the secondary cooling tubes of the former burner means become the primary cooling tubes of the latter burner means.

Other features and advantages will be readily apparent when considered in view of the drawings and description in which:

FIG. 1 is a front view of a fragmentary portion of a furnace wall illustrating the novel nozzle cooling arrangement of this invention as seen from within the furnace;

FIG. 2 is a side view of the arrangement illustrated in FIG. 1; 7

FIG. 3 is a detail side view of a single burner nozzle cooling arrangement of this invention;

FIG. 4 is a section taken along line 44 of FIG. 3;

FIG. 5 is a vertical sectional view of a furnace chamber of a forced flow steam generator incorporating the teaching of the present invention having a somewhat modified burner nozzle arrangement; 7

FIG. 6 is a plan section view taken along line 6-6 of FIG. 5;

FIG. 7 is a diagrammatic expanded or developed view the included wall and one-half of each adjacent wall illustrating the relative interchange position of the tubes; and 7 FIG. 8 is a detail front furnace view of a modified arrangement of the interchange tube arrangement.

According to this invention the furnace section 10 of a forced flow steam generator as viewed in FIGS. 5 and 6 include upright front, rear and

side walls

11, 12, 13 and 14 respectively having their adjacent ends connected by relatively short angularly disposed

corner walls

15, 16, 17 and 18 to define a furnace chamber 19 which is substantially rectangular in cross-section having cut-off corner portions, and .the walls lined with fluid cooling tubes as will be hereinafter described. A burner means 20 arranged in each of the corner walls for pulverized coal firing, discharges combustible constituents in a direction substantially tangential to an imaginary vertical cylinder Each burner posed nozzles generally indicated by numeral 21 in FIG.

5, projecting through a wall opening defined by wall cooling tubes as will be hereinafter described. As shown in FIGS. 1 and 2 the nozzles may be either all circular in cross-section or as shown in FIG. 5 may have other cross-sectional shapes, the nozzles of each burner means discharging either pulverized fuel and/ or combustion air. For example, in FIGS. 1 and 2 the

larger diameter nozzles

43, 47, 49 and 51 discharge combustion air and the

smaller ones

44, 45, 46, 48, 50 and 52, the fuel to be mixed therewith. In FIGS. 5, 7 and 8, the rectangular nozzle may be considered as the air discharge nozzles and the round ones the fuel discharge nozzles.

7 As the nozzles of the burner means described are exposed to the radiant heat generated in the furnace cham- 'ber, rapid oxidation and subsequent failure of the nozzle castings may result in the absence of any means for cooling the same. According to this invention cooling of the nozzles is occasioned by utilizing the fluid cooling tubes of the furnace walls for effectively cooling the nozzles of the burner means. Referring to FIGS. 1 and 2 nozzle cooling is accomplished by a plurality of wall tubes 22 to 41 which form a single tube group 42 which is composed of two parts or sub-groups, namely the internal tubes consisting of tubes 27 to 36 which serve as the primary nozzle cooling tubes and the external tube sub-group comprising tubes 22 to 26 and 37 to 41 which form the secondary cooling tubes and more or less frame or define the openings through which the nozzles project. Each of the tubes 27 to 36 comprising the primary cooling tube sub-group tip of its respective nozzle in intimate contact therewith 2 as shown in FIGS. 1 to 4.

As seen in FIGS. 1 and 2 the tubes 27 to 36 extending longitudinally in a common plane are bent out of the plane in the region of the nozzles 43 to 52 and the tubes 27, to 36 are then coiled about nozzles 43 to 52, respec- 30 tively as shown, and thus effectively cool each nozzle individually. For example, tube 32 is bent out of the common plane and wound several times about nozzle 43, thence as a lower input tube extends upwardly alongside the other nozzles up to the elevation of nozzle 52 where it is then arranged back into the plane of the wall.

The other external tubes or sub-group 22 to 26; 37 to 41, extend longitudinally in the plane of the burner wall with tubes 22 to 26 and tubes 37 to 41 disposed on opposite sides of the nozzles,

tubes

25, 26, 37 and 38 passing in serpentine fashion on either side of the nozzles 43 to 52 to frame the same. The external tubes 22 to' 26 and 37 to function as secondary cooling tubes in that they will intercept any radiant heat which they see. I

. In FIGS. 5 and 6 there is shown a furnace chamber 19 of a steam generating unit arranged for corner firing and has a slag tap opening 53 in the bottom thereof. The burner means nozzle arrangement at the corners is somewhat modified from that shown in FIGS. 1 and 2 in that seven nozzles 54 to 60 are vertically arranged at each corner and comprise both round and rectangular nozzles in cross-section. The furnace walls of the illustrated arrangement in FIGS. 5 and 6 are cooled by two

tube groups

61, 62 and as there are four burner means 20, the instant arrangement is such that two burner means fall within a single tube group. As seven nozzles are included in each burner means, each

tube group

61, 62 consists of at least fourteen tubes. The tube cover of the furnace walls by a' single tube group 61 of the present slagging furnace chamber is formed as shown in FIG. 7 in which the tubes extend vertically and longitudinally in-the adja- "cent angularly disposed

burner walls

15 and 16 and having 'the continuations thereof extending as serpentine or return bend tubes with horizontally and vertically spaced tube legs, the tubes being connected for a parallel flow of fluid therethrough. In this arrangement each

group

61, 62 supplies two of the corner burner walls, the intermediate furnace wall, and one-half of each opposed adjacent wall.

According to this invention the nozzle cooling tubes are arranged in a group or band 61 parallel to one another and enter into the furnace wall 14, for instance, from below as indicated by the arrow A in FIG. 7, and line half of wall 14 in a serpentine or return. bend fashion. In the *first' burner-wall -15 the tubes extend longitudinally downward and there divide into sub-groups which constitute the primary and secondary nozzle cooling tubes as hereinbefore described. After leaving the first burner wall 15, the tubes are brought into alignment and then cover the entire furnace wall 11 between the two burners, the tubes again assuming the horizontally extending serpentine arrangement. 'Ihence the tubes pass into the second burner wall portion 16 as longitudinally downwardly extending tubes for cooling of the nozzles of the second burner as hereinbefore described. After leaving the second burner wall 16 the tubes extend in a serpentine fashion to cover half of the adjacent furnace wall 13 and are there deflected upwardly as indicated by the arrow B in FIG. 7.

According to this invention the tubes comprising the sub-group forming the primary cooling tubes in the first burner wall 15 change their relative position within the band'61 at a point intermediate between the two burner means as indicated at '63, 64 in order to fulfill the condition that the tubes forming the primary cooling of the first burner means become the secondary cooling tubes of the second burner means and that the secondary cooling tubes of the former become the primary cooling tubes of the latter.

It will be noted that the crossover of the tubes may occur at some other point intermediate the two burner means and as shown in FIG. 8 may occur in the burner wall 16 at 65. This arrangement permits a more simplified wall lining of the included furnace wall 11, for example. Thus the tube crossover effectively equalizes the amount of heat absorbed for any given tube.

his to benoted that it would be possible to use a single cooling tube to cool several nozzles, in which case it is either possible to omit some of the cooling tubes entirely from the nozzle cooling scheme or to use all of them for nozzle cooling. The particular arrangement will depend upon a particular furnace arrangement. It is important, however, that in any event the heat input to the individual tubes be adjusted to equivalence.

While in accordance with the provisions of the statutes we have illustrated and described herein specific forms of the invention now known to us, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the :spirit of the invention covered by our claims, and that certain features of'the invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is:

1. In a forced flow vapor generator, a substantially rectangular chamber defined by upright walls connected by relatively short angularly disposed corner walls, a burner means having a plurality of nozzles arranged in each of said corner walls to discharge a combustible material in a direction substantially tangential to an imaginary vertical cylinder located centrally of the furnace chamber, said walls including two groups of continuous fluid cooled tubes connected for parallel fluid flow, each tube group being arranged to cool a pair of said corner 'walls, the'included wall and one half of each adjacently connected walls, the number of tubes in each of said groups being at least equal to the number of burner nozzlesdisposed in the corner walls served by each of said groups, said tubes in said corner walls extending longit'udinally thereof with extensions thereof arranged in the included and adjacent walls as return bend tubes having horizontally and vertically spaced tube legs, a portion of the tubes extending in one of said corner walls being arranged to effect primary cooling of the burner nozzles disposed therein and a second portion thereof for affecting secondary cooling of said nozzles; the relative position of said primary and secondary nozzle cooling tubes being interchanged at an intermediate portion thereof so that the primary nozzle cooling tubes in one of said corner walls become the secondary nozzle cooling tube in said'other corner wall and the secondary nozzle cooling tubes becoming the primary nozzle cooling tubes in said other corner wall.

2. In a forced flow vapor generator, a substantially rectangular chamber defined by upright walls connected by relatively short angularly disposed corner walls, a burner means having a plurality of nozzles arranged in each of said corner walls to discharge a combustible material into the furnace chamber, said'w'alls including two groups of continuous fluid cooled tubes connected for parallel fluid flow, each tube group being arranged to cool a pair of said corner walls, the included wall and one half of each adjacently connected wall, the number of tubes in each of said groups being at least equal to the number of burner nozzles disposed in the corner walls served by each of said groups, said tubes in said corner walls extending longitudinally thereof with extensions thereof arranged in the included and adjacent walls as return bend tubes having horizontally and vertically spaced tube legs, a portion of the tubes extending in one of said corner walls being arranged to effect primary cooling and a second portion thereof for effecting secondary cooling of the burner nozzles disposed therein, the position of said primary and secondary nozzle cooling tubes being interchanged relative to each other at an intermediate portion of said tubes so that the primary nozzle cooling tubes of one of said corner walls become the secondary nozzle cooling tube in said other corner wall and the secondary nozzle cooling tubes becoming the primary nozzle cooling tubes in said other corner wall, the primary cooling tubes in each of said corner walls having a portion thereof helically coiled about a burner nozzle in intimate contact therewith.

3. A forced flow vapor generator comprising a plurality of enclosing wall portions defining a furnace chamber, a plurality of fluid cooled tubes connected for parallel fluid flow therethrough lining said wall portions, a first burner and a second burner disposed in spaced relationship with respect to one another, each of said burners having a plurality of spaced nozzles arranged to discharge a combustible constituent through its respective wall portion into said furnace chamber for generating heating products of combustion, said tubes including a first series and a second series of continuous tubes, the tubes of said first series having a first portion arranged to effect primary cooling of the nozzles of said first burner disposed in one wall portion and having a second portion forming a continuation thereof arranged to effect secondary cooling of the nozzles of said second burner disposed in another of said wall portions, and the tubes of said second series having a first portion arranged to effect secondary cooling of said first burner nozzles and having a second portion forming a continuation thereof arranged to effect primary cooling of said second burner nozzles.

4. The invention as defined in claim 3, wherein the number of tubes in said first series is at least equal to the number of nozzles in said first burner, and the number of tubes included in said second series is at least equal to the number of nozzles in said second burner, the primary cooling portions of the respective tubes in each of said first and second series having an intermediate portion thereof helically wound about a respective burner nozzle in intimate contact therewith to enhance the primary cooling thereof.

5. A forced flow vapor generator comprising a plurality of enclosing wall portions defining a furnace chamber, a plurality of fluid cooling tubes connected for parallel fluid flow therethrough lining said wall portions, a first burner and a second burner disposed in spaced relationship with respect to one another, each of said burners being disposed in a respective wall portion of said furnace chamber, and each of said burners having a plurality of spaced nozzles arranged to discharge a combustible constituent through its respective wall portion into said furnace chamber for generating heating products of combustion, said tubes including a first series of con- .the first tube portions and second tube portions of the first and second tube series which effect primary cooling of the first and second burner nozzles, respectively, being displaced out of the plane of their respective burner wall portion so as to be disposed in shielding relationship with respect to the secondary cooling tube portions of said first and second tube series adjacent the respective burner nozzles,

6. In a forced flow vapor generator, a setting comprising upright front, rear and side walls and four relatively short angularly disposed corner walls connecting adjacent end portions of said front, rear and side walls to define a substantially rectangular furnace, a burner having a plurality of vertically spaced nozzles disposed in each of said angularly disposed corner walls, said nozzles being arranged to discharge a combustible constituent in a direction substantially tangential to an imaginary cylinder located centrally of the furnace chamber, said walls including a plurality of fluid cooled tubes connected for parallel flow therethrough, said wall tubes including a first group of continuous tubes in which each tube has portions thereof lining two of said angularly disposed corner walls, included wall, and one half of each of said adjacent side walls, and a second group of continuous tubes in which each tube has portions thereof lining the other two angularly disposed walls, included wall, and the other half portion of each adjacent side wall, each group of wall tubes including a first portion thereof arranged to effect primary cooling and a second portion thereof arranged to effect secondary cooling of the burner nozzles in one angularly disposed wall portion, and in each of said tube groups the relative positions of their respective primary and secondary cooling tubes are interchanged with respect to each other in the included wall between said angularly disposed corner walls served by the respective tube groups so that the primary cooling tubes in one of said angularly disposed corner walls become the secondary cooling tubes of the burner nozzles disposed in the other angular corner wall and the secondary nozzle cooling tubes in said one angularly disposed wall becoming the primary cooling tubes of the burner nozzle disposed in the other angularly disposed burner wall.

7. The invention as defined in claim 6, wherein the tubes in each of said first and second groups include longitudinally extending tubes in their respective angularly disposed corner walls and continuations of said longitudinal tubes extending in the adjacent walls as return bend tubes having horizontally arranged vertically spaced tube portions.

8t The invention as defined in claim 7, wherein the longitudinally extending tubes in the angular walls have a portion thereof coiled about one of the burner nozzles disposed therein for cooling the same.

9. A forced flow vapor generator comprising a plurality of enclosing wall portions defining a furnace chamher, a plurality of fluid cooling tubes connected for parallel flow therethrough, a first burner and a second burner, each having a nozzle discharging combustible constituents into said furnace chamber for generating heating products of combustion, each burner nozzle being spaced one from the other and disposed in respective Wall portions of said furnace chamber, a portion of said wall tubes being arranged to effect primary cooling of the first burner nozzle disposed in one wall portion, and

a second portion of said tubes for efiecting secondary cooling of said second burner nozzle disposed in another wall portion, the relative position of said primary and secondary cooling tubes being interchanged at an intermediate portion thereof positioned between the respective burner wall portions so that the primary cooling tubes of the first burner nozzle disposed in one wall portion become the secondary cooling tubes of the second burner nozzle disposed in the other burner wall portion, and the secondary cooling tubes of the first burner nozzle in said one wall portion become the primary cooling tubes of the second burner nozzle in said other burner wall portion.

10. A forced flow vapor generator comprising a furnace chamber having a burner wall portion, a burner having a plurality of nozzles disposed in spaced alignment in said burner wall, said nozzles being arranged to discharge a combustible constituent into said furnace chamber, and means for cooling each of said nozzles, said means including a plurality of fluid cooled tubes lining said burner wall, said tubes being connected for parallel fluid flow therethrough, a portion of said tubes being disposed in the plane of said wall adjacent said spaced nozzles to effect secondary cooling of said nozzles, and another portion of said tubes being bent out of the plane of said wall and disposed in shielding relationship with respect to said first portion of said tubes, and each tube of said second portion having an intermediate portion thereof coiled about one of the burner nozzles in said wall to enhance primary cooling thereof.

11. A forced flow vapor generator comprising a furnace chamber having a burner wall portion, a burner having a plurality of nozzles disposed in spaced alignment in said means including a plurality of tubes, said tubes being connected for parallel fluid flow therethrough, a portion of said tubes being disposed in the plane of said wall on either side of said spaced nozzles to effect secondary cooling of said nozzles, and a second portion of said tubes including a number of tubes corresponding to the number of said burner nozzles, each tube of said second portion being bent out of the plane of said wall to extend alongside each of said burner nozzles in shielding relationship with respect to the tubes of said first mentioned portion, and each of said tubes of said second portion having an intermediate part thereof coiled about a respective burner nozzle to effect primary cooling thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,936,161 Hedrich Nov. 21, 1933 2,285,442 Kerr June 9, 1942 2,697,422 Arm-aeost Dec. 21, 1954 FOREIGN PATENTS 181,598 Austria Apr. 12, 1955 903,630 France Oct. 10, 1945 1,126,248 France Nov. 19, 1956 66,168 Norway May 3, 1943