US2897794A

US2897794A - Steam generating unit with plural combustion chambers separated by a partition wall of steam generating tubes

Info

Publication number: US2897794A
Application number: US500226A
Authority: US
Inventors: Otto Heinrich; Mogk August
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1948-10-01
Filing date: 1955-03-21
Publication date: 1959-08-04
Anticipated expiration: 1976-08-04

Description

Aug. 4, 1959 H. OTTO ETAL 2,897,794

STEAM GENERATING UNIT WITH PLURAL COMBUSTION CHAMBERS SEPARATED BY A PARTITION WALL OF STEAM GENERATING TUBES 3 Sheets-Sheet 1 Filed March 21-, 1955 s m K Y Y R E m m m m N N H M y m m w. T A w. m w m D Q x a 1 man b m fin 9 .1 u u g ,QQM D *1 m r 2 m5 0 H H H mow m n .l own 9 9 Q n. mv F 03 mm. on u mmm mmm h QFMD DGOM m 96 i D D W! IO M NF H n Aug. 4, 1959 H. OTTO ET AL 2,897,794

STEAM GENERATING UNIT WITH PLURAL COMBUSTION CHAMBERS SEPARATED BY A PARTITION WALL OF STEAM GENERATING TUBES Filed March 21, 1955 5 Sheets-Sheet 2 FIGS - 4 1 w i 6b z 2 ;1ab E 1b I i 4b, F 4

L 25b -\2Ob 3 28b 20a 24a 25a 28a 4a 12a 3L 2 1 5 \wa g 253 186 3a 5 27a II;/ E, FLA 22a 23a INVENTORS HEINRICH OTTO By AUGUST MOGK 6'; ATTORNEY Aug. 4, 1959 H. OTTO ET AL 2,897,794

STEAM GENERATING uNIT WITH PLURAL COMBUSTION CHAMBERS SEPARATED BY A PARTITION WALL OF sTEAM GENERATING TUBES 3 Sheets-Sheet 5 Filed March 21, 1955 3 9 i m m m m wwW T U D D D D D D D D D D DN m m w W m mw m W. M m M 3 m 0E EN m m .3 m mm E 1 LQQQEQ QL QM LQ A M g, L Q E y L 7U xii/L \n\ 7%, 7 1 Y W 1 1 mm o l fi W3 j m 2 L fi L A United States Patent Heinrich Otto and August Mogk, Oberhausen, Rhineland,

Germany, assignors to The Bahcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Application March 21, 1955, Serial No. 500,226

Germany October 1, 1948 Public Law 619, August 23, 1954 Patent expires October 1, 1968 3 Claims. (Cl. 122-440) This invention relates to improvements in a water tube steam generating and superheating unit, in which a predominant percentage of the steam is generated in upright furnace wall tubes disposed along the walls of at least two separately fired combustion chambers, which have a common partition wall including closely spaced upright steam generating tubes.

The invention involves the arrangement of fuel burners at spaced positions around the perimeter of each of the combustion chambers, with some of the fuel burners arranged at one level and some at a different level in order that overheating of the steam generating tubes of the partition wall may be avoided.

The invention also involves a specific construction of a furnace partition wall dividing two of the furnace chambers, wherein the closely spaced and wall aligned upright steam generating tubes constituting the main part of the partition wall are strengthened and maintained in their operative wall forming positions by other upwardly extending steam generating tubes, parts of which are arranged so as to extend across the faces of the partition wall. In a more specific sense the invention involves steam generating tubes having oppositely inclined sections disposed on opposite sides of the tubular partition wall, and closely related thereto to maintain the integrity of the partition wall under conditions wherein different combustion gas pressures may exist on opposite sides of the wall.

The invention will be concisely set forth in the claims which are appended hereto, but for a more complete understanding of the invention, its uses and advantages, recourse should be had to the following description which has reference to the accompanying drawings wherein a preferred embodiment of the invention is illustrated.

In the drawings:

Fig. l is a sectional side elevation of the steam generating and superheating unit looking toward the medial plane thereof;

Fig. 2 is a sectional front elevation taken on line 22 of Fig. 1;

Fig. 3 is a sectional plan View of the furnace of the illustrative steam generating and superheating unit, showing the two combustion chambers separated by a common wall;

Fig. 4 is a side view, on a larger scale, of a portion of the partition wall between the two combustion chambers;

Fig. 5 is a sectional plan, taken on the line 5-5 of Fig. 4; and

Fig. 6 is a flow diagram for combustion air, feed-water and steam.

In the drawings corresponding parts of the unit to the right and to the left of the medial plane are denoted by the same reference numerals, but are differentiated by the indices a and b, respectively. Thus, the furnace of 'the'illustrative unit consists of two combustion cham "ice":

bers

1a and 1b, as clearly indicated in Figs. 2 and 3. These combustion chambers may be considered as having outer walls lined with upright steam generating and wall cooling tubes 2a, 3a and 4a for the combustion chamber 1a, and with

tubes

2b, 3b, and 4b, respectively, for the combustion chamber 1b. The combustion chambers are divided by a common wall or partition wall generally indicated at 5.

The wall tubes lining the outer walls of the combustion chamber are closely arranged, and, preferably, in con-- tact with one another, and they are connected at their lower ends and their upper ends with appropriate headers, the upper headers being connected by riser tubes to a steam and water drum 6, which is connected by down-- comers to the lower headers so as to complete natural circulation paths.

The steam generating riser tubes 7a and 7b (Fig. 2) of the combustion chamber rear wall tubes 4a and 4b extend forwardly over lower parts thereof, while their intermediate parts are spaced apart and brought into a number of tube rows parallel to the medial plane of the unit in order to provide gas flow openings of suflicient cross-sectional flow area for the flow of gases from the upper part of the furnace into the convection gas pass. Thus, the intermediate parts of these tubes may be said to form the screen 7 (Fig. 1) between the upper part of the furnace and the convection gas pass.

The upright steam generating tubes of the partition wall 5 between the

combustion chambers

1a and 1b extend vertically from a lower header 8, which is connected by appropriate downcomers with the steam and water drum 6, to the upper headers 9 and 10 (Fig. 1), connected respectively by appropriate risers or circulators 11 and 12 to the steam and water drum 6. The upper parts of the wall tubes of the partition wall are disposed between the groups of screen tubes 7a. and 7b disposed between the top of the furnace and the convection gas pass.

As shown more particularly by Figs. 4 :and 5, the

outer-most tubes

13 and 14 at the opposite edges of the lower portion of the furnace partition wall or division wall are bent sidewardly, so as to extend at upward inclinations and in opposite directions across opposite sides of the partition wall to the tubes of which they are connected by welding.

Such tubes

13 and 14 extend in their upwardly inclined relationship to the positions indicated at D and E in Fig. 4, where these tubes return to their wall alignment positions with respect to the wall tubes 2a and 4a.

Also adjacent the positions D and E of Fig. 4, the stem generating

wall tubes

15 and 16 of the front and rear furnace walls, immediately adjacent the edges of the partition wall and the upper ends of the inclined portions of the

tubes

14 and 13 respectively, are bent, sidewardly as indicated in Figs. 1 and 4, so as to extend. at upward inclinations in opposite directions, and at opposite sides of and across the partition wall.

The tubes having the

inclined portions

13 and 14 are, as indicated in Fig. 1, taken out of the rows of tubes along the opposite sides of the hopper bottom of the furnace, while the upper vertical portions of the

tubes

13 and 14 beyond their inclined portions take the place of the

tubes

15 and 16 in the front and rear walls 2a and 4a.

The upper end of the tube having the inclined part 15 passes between two of the steam generating riser tubes, and groups of screen tubes at 7a and 7b, and passes through a wing wall or arch wall 50 extending inwardly with respect to the pertinent combustion chamber and at a position between the combustion chamber and the convection gas pass. The tube having the inclined section 16 continues upwardly between the tubes 2a and 2b, some of which serve to line the furnace roof.

The

combustion chambers

1a and 1b are respectively fired by

burners

17a, 18a, 19a and 20a, and 17b, 18b, 19b and 20b, disposed at the corners of the combustion chambers as indicated in Fig. 3 of the drawings. ASSOCI- ated with the burners are the pulverized fuel conduits 21 22a, 235:, 24a, 21b, 22b, 23b and 24b, and the

secondary air ducts

25a, 26a, 27a, 28a, 25b, 26 b, 271 and 28b.

With the simultaneous heating of the partition wall tubes from opposite sides, some of the tubes are apt to be over-heated, and in order to reduce or overcome this danger, adjacent firing means at opposite sides of the partition wall are arranged at different levels. Thus, the fuel burners of the combustion chamber 1a may be at a level different from that of the burners of the combustion chamber 1b. Alternatively, the

burners

17b, 20b, 18a and 191 may be disposed at one level, and the

remaining burners

17a, 19a, 18b and 20b may be disposed at a different level. Such disposition of the burners at opposite sides of the partition wall at substantially different levels also facilitates the installation of the pulverized fuel conduits and the secondary air ducts.

Arranged in the gas flow path beyond the combustion chambers, and on the same side of the medial plane of the unit as the combustion chamber 1a, are three superheater sections. The first section includes the tube groups 29a and 30a, including banks of series connected and spaced return bend tubes. The second section includes the banks of tubes, or

tube groups

31a and 32a, which are similar to the preceding groups of tubes. The third superheater section includes the banks of

tubes

33a and 34a. The tube groups, or banks of tubes 29a to 33a inclusive are arranged in the horizontal gas pass, and the bank of tubes 34a is disposed in a subsequent downfiow gas pass as clearly indicated in Fig. 1.

As indicated in Fig. 6, similar superheater tube groups, similarly arranged, are provided on the other side of the medial plane of the unit and in the flow of heating gases beyond the furnace. Thus, two parallel steam circuits extend through the superheater from the steam and water drum 6. One of these circuits includes the banks of

tubes

34a, 33a, 29a, and 30a, and an attemperator 41a, disposed at one side of the boiler. The other circuit includes the tube groups 34b, 33b, 29b, 36b and attemperator 41b, disposed at the other side of the boiler.

The tubes of the groups or banks of tubes 34a and 34b are continued in the groups or banks of tubes 33a and 33b and thence, extend, as indicated in Fig. 1, as roof tubes over the horizontal gas pass to the headers of the tube groups or banks of tubes 29a and 2%. In the superheater arrangement described, since each of the two parallel heat exchange steam flow paths lies partly in the gas stream path from one combustion chamber, and partly in the gas stream path from the other combustion chamber, a more even heating of the steam is achieved than otherwise would be the case when the temperatures and the rates of flow of the gas streams from the combustion chambers, are unequal. If desired, the cross-connections in the steam flow paths may be effected before the attemperators, rather than after the attemperators, as shown.

Referring particularly to Fig. 6, separated steam flows from the steam and water drum 6 through the line 51, to and through the tubes of the group 34a and then through the tubes of the group 33a. Thence the steam flows through the line 51a to and through the tubes of the bank of tubes 29a. From these tubes the steam then flows through the group ofvtubes 30a, to and through the attemp erator 41a. Thence the, steam flow through the cross-over line 52 to and through the tubes 32b; and then to and through the tubes of the group 3112, to the turbine supply line 53 which is throttled at 54..

Further referring to Fig. 6, the separated steam .fiows from the steam and water drum above. the combustion chamber 1! through the line 55 to the group of tubes 34b. Thence the steam flows through these tubes and then through the tubes of the group 33b. Thence steam flows through the line 56 to and through the tubes 2%; then to and through the tubes 30b. From these tubes the steam flows through the attemperator 41b, and then through the line 57 to and through the tubes 32a. Thence the steam flows to the tubes 31a; then through said tubes, and then through the line 53.

After flowing over the superheater tubes, the furnace gases pass through the recuperative air heaters 35a and 35b, of suitable known form. The gases then pass over and between the tubes of the

groups

36a, 36b, 37a, 37b, 38a, 38b, 39a and 39b of the feedwater heater or steaming economizer, and then through the regenerative air heaters 40a, and 40b, also of suitable known form.

As diagrammatically illustrated in Fig. 6, the air flows from the inlets 64 and 66 through the air heaters 40a and 40b, and then through the

cross-over lines

68 and 70 to the air heaters 35b and 35a respectively. The air thence flows through the lines 72 and 74 to the junction point 76 of two lines 78 and 80, which conduct combustion supporting air to the sets of burners of the respective combustion chambers.

The feedwater heater includes four sections, two of which are formed respectively by the banks of

tubes

39a and 38a, and the tube groups 37a and 36:: on one side.

of the medial plane of the unit, and two of which are formed respectively by the tube groups 3% and 38b, and the tube groups 37b and 36b on the other side of the medial plane. Feedwater is supplied to the inlet headers associated with the tube groups 39A and 39B, from the line 82. Between these headers and the steam and water drum 6, there are two parallel feedwater flow paths as indicated in Fig. 6. One of these paths includes the banks of tubes or the groups of

tubes

39a and 38a. A cross-connection is disposed between the mixing header at the outlet of the tube group 38a and an inlet header of the tube group 3712. Another cross-connection 92 leads from a mixing header at the outlet of the tube group 3812 to the group of tubes 37a, whence the feedwater flow continues through the group of tubes 36a and then to the line 94. Similarly, the cross-connection 90 leads to the group of tubes 37b whence the feedwater flows through the group of tubes 36]), and then to connection with the line 96 leading to the steam and water drum. The line 94, likewise conducts feedwater from the group of tubes 36a to the steam and water drum. The regenerative air headers 40a and 40b, supplied by separate forced draft fans respectively, are also respectively cross-connected to the other air heaters 35A and 35B.

Although the invention has been described with reference to the details of one preferred embodiment shown in the drawings, it is to be appreciated that the invention is not limited to all the details thereof. It is rather to be taken as of a scope commensurate with the scope of the subjoined claims.

What is claimed is:

1. In a steam generating and superheating unit, a furnace having walls including steam generating tubes, other steam generating tubes in row alignment transversely of the furnace and dividing the furnace into a plurality of combustion chambers, the walls of said furnace having indentations adjacent the ends of the division wall, steam generating tubes in the opposite walls of said furnace adjacent the ends of said division wall being bent out of their wall alignment to extend across said division wall and to be attached thereto, the lower portion of each of said bent furnace wall tubes being aligned in one furnace wall and the upper portion being aligned in an opposite furnace wall, fuel burners arranged adjacent the corners of the combustion chambers so as to tangentially fire the combustion chambers, there being sets of these burners in each combustion chamber adjacent the division wall and positioned in said indentations, a superheater receiving steam generated in the furnace wall tubes and arranged to be heated by the furnace gases, gas-pass wall means forming a gas passage leading from the furnace gas outlet, and steam and water flow connections providing for the flow of water to the inlets of the steam generating tubes and including a steam water drum and upper and lower furnace wall headers with the headers disposed exteriorly of the combustion chambers, the furnace wall tubes extending to positions wherein they are connected to the upper and lower headers outside of the combustion chambers.

2. In a steam generating unit having a furnace, a row of upright closely arranged steam generating tubes in the walls of said furnace, other upright and closely arranged steam generating tubes defining a furnace partition wall separating the furnace into two combustion chambers, at least one steam generating tube having its lower portion in a wall of said furnace extending transversely of said partition wall and having its intermediate portion bent out of its wall alignment in an upwardly inclined section extending across and secured to said partition wall, said tube having its upper portion aligned with the row of wall tubes along the wall of the furnace opposite to the wall of its lower portion, a steam and water drum, connections between the upright ends of the steam generating tubes and the steam and water drum, means including downcomers connecting the water space of the drum to the inlets of the steam generating tubes, and fuel burning means for separately firing the separate combustion chambers.

3. In a steam generating unit having a furnace, a row of upright closely arranged steam generating tubes in the walls of said furnace, other upright and closely arranged steam generating tubes extending from one side wall to an opposite side wall of said furnace and defining a furnace partition wall separating the furnace into two combustion chambers, steam generating tubes in opposite side walls of said furnace having intermediate portions bent out of their side wall alignment to form upwardly inclined sections extending across and secured to said partition wall, each of said tubes having their upper portions aligned with the side wall tubes along the side wall of the furnace opposite to the side wall of their lower portions, a steam and water drum, connections between the upright ends of the steam generating tubes and the steam and water drum, means including downcomers connecting the water space of the drum to the inlets of the steam generating tubes, and fuel burning means for separately firing the separate combustion chambers.

References Cited in the file of this patent UNITED STATES PATENTS 1,775,336 Wood Sept. 9, 1930 2,035,763 Robinson Mar. 31, 1936 2,243,909 Kruger June 3, 1941 2,308,762 Krug et a1 Jan. 19, 1943 2,334,187 Frisch Nov. 16, 1943 2,594,471 Marshall Apr. 29, 1952 FOREIGN PATENTS 57,737 Denmark June 17, 1940 682,121 Great Britain Nov. 5, 1952