US2310801A

US2310801A - Steam generator

Info

Publication number: US2310801A
Application number: US219562A
Authority: US
Inventors: Dana H N Mayo; Arthur E Raynor
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1938-07-16
Filing date: 1938-07-16
Publication date: 1943-02-09
Anticipated expiration: 1960-02-09

Description

Feb. 9, 1943.

D. H. N. MAYO ETAL 2,310,801

STEAM GENERATOR Filed July 16. 1958 4 Sheeqs-Sheet 1 Fig] Dana'HJV Ar hurE/Payzzar ATTORNEY.

I Feb. 9, 1943. D. H. N. MAYO ETAL 2,310,801

STEAM GENERATOR Filed July 16, 1938 4 Sheets-Sheet 2 INVENTORS Dana H/VMayo' 4 I Ari/7:11 Zi/Paynor ATTORNEY;

1943- D. H. N. MAYO ETAL 2,310,801

STEAM GENERATOR Filed July 16, 1938 4 Sheets-Sheet 3 INVENTORS Dana H NMayo 2w Ari/var E. Eayna'z" ATTORNEY.

Feb. 9, 1943. D. H. N; MAYO ETAL STEAM GENERATOR Filed July 16, 1938 4 sheets-s eet 4 IN VENTORS TQ v x? W S SJHJH S 3 SA C Qn O ,r 0 O O A O H o H O J L /o 4 O L L1 4 4 O Dana IVA/Mayo 2 d 1 12f hurEEaynor ATTORNEY.

Patented Feb. 9, 1943 UNITED STATES PATENT OFFICE STEAM GENERATOR Dana 11. N. Mayo, Ridgewood, N. 1., and Arthur E. Raynor, Rockville Centre, N. Y., assignors to The Babcock a Wilcox Company, Newark, N. 1., a corporation of N ew Jersey Application July 16, 1938, Serial No. 219,562

13 Claims.

iliary water heating, 1. e. economizer surface.

The main object of the invention is the provision of an improved arrangement and constructlon of the economizer in a steam generator of the character described which is characterized by the simplicity and effectiveness of the'economizer surface supporting provisions, the accessibility of the economizer surface for renewal and inspection, the protection of the by-pass control parts from overheating, and the high thermal efllciency of the steam generator unit with the by-pass in or out of use.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which wehave illustrated and described a preferred embodiment of the invention.

Of the drawings:

Fig.1 is a partly diagrammatic sectional elevation of a steam generating unit incorporating the invention;

Fig. 2 is an enlarged view of an upper portion Fig. 11 is a vertical section taken on the line I I-l l of Fig. 10.

In the drawings the invention is illustrated as incorporated in a steam generator-of the Babcock & Wilcox high head type comprising a two-stage pulverized coal burning furnace having a primary section III and a secondary section II. The

primary furnace section It is defined by fully studded tube walls designed for the maintenance therein of a normal mean furnace temperature above the ash fusion temperature of the coal used. nozzles I2 are arranged to downwardly discharge through the arch l3 of the primary section. A

: water cooled floor I4 is constructed to collect and support a layer of molten slag in the primary section Hi which is withdrawable therefrom through a slag tap opening IS in one of the side walls adjacent the floor level. The primary fur Fig. 7 is a plan view of the structure shown in Fig. 6;

Fig. 8 is a vertical section taken'on the line 8-8 of Fig. 6;

Fig. 9 is a vertical section taken on the line 99 of Fig. 2;

Fig. 10 is an enlarged view of -a portion of Fig. 2; and

nace section is partly'separated from the secondary section by a fluid cooled partition it formed by refractory covered fully studded water tubes having their'lower portions bent out of the plane of the tube row to form a series of transversely spaced gas passages l'l connecting the primary and secondary furnace sections.

The secondary furnace section II is of conthe boiler circulation system hereinafter de'-'-"" scribed.

The convection heated pressure parts of the unit comprise a bank of steeply inclined steam generating tubes 20 extending between rows of vertical uptake and supply headers 2| and 22 respectively. The lowermostrow of tubes 20 exheaders 2| and a horizontal cross header 2! arranged below and connected to the supply headers 22 by nipples 24. Alternate tubes in this row are bent differently to form a slag screen to protect the remaining portion of the bank. A steam and water drum 25 is arranged transversely of and at a substantial distance above the tube bank A plurality of pulverized coal burning 22. A row of circulator tubes 26 starting at the top of the uptake headers 2| connects them to the steam space of the drum 25, while another row of circulator tubes 21 connects the water space-of the drum to the cross header 23. Another row of tubes 26 extends vertically from the upper end of the supply headers 22 into a cross header 29 which is connected to the steam space of the drum 25 by tubes 30. The intertube spaces of the row of tubes 28 and nipples 24 are closed by refractory material to define a vertical bailie structure 3i forming with the row of supply headers 22 a continuation of the front side of the secondary furnace section to the header 29. The vertical portions of the downtake circulator tubes 21 also have their intertube spaces closed by refractory to define a wall 32 parallel to the baflle wall 3i.

With the described construction the space enclosed by the tube bank 20, uptake circulators 2'6, drum 25, and downtake clrculators 21 is divided by the baiiie structure 3| into an upflow section 35, the sides of which form an extension of the secondary furnace section sides, and a downfiow section 36 between the battle 3| and the wall 32, the downflow section being substantially wholly at the front side of the headers 22. An inclined refractory baiile 31 extends downwardly from the lower portion of the baiiie structure 3| in a plane spaced from the lower end of thewall 32 to provide a heating gas exit from the lower end of the downflow section 36 to an external air heater and stack connection. The portions of some of the circulator tubes 21 extending across the gas exit are bent out of a single row to provide space for the gas exit.

The portion of the setting occupied by the gas upflow and downflow sections is of substantial volume and advantageously employed for the location of the convection heated auxiliary fluid heating surface of the unit. The auxiliary fluid heating surface comprises serially connected vertically spaced banks of multiple-looped horizontally arranged superheater tubes 40 arranged in flat coils extending between superheater inlet and outlet headers 4| and 42 respectively, with the tube coils vertically arranged and extending from the uptake circulator tubes 26 to a point rearwardly of the tube row 28. The space between the forward ends of the superheater coils and the bafile structure3l is employed as an upflow by-pass passage 35a for controlling the heat absorption of the superheater tubes as hereinafter described. A row of tubes 44 extends inwardly and upwardly from the upper level of the supply headers 22 adjacent the forward. ends of the superheater tube coils to a transverse header 45 arranged parallel to and spaced from the header 29. Tubes 46 extend vertically from the header 45 and then laterally to the steam space of the drum 25. The portions of the tubes 44 opposite the superheater tube coils have their intertube spaces closed by refractory to define a vertical baffle 41 extending from the header 45 to a point below the superheater tube bank and forming the rear side of the gas by-pass passa e 35a and separating it from the main up-pass 35.

Steam generating units of the character described are designed for the production of high pressure superheated steam with steam temperatures approximately 950 F. at the superheater outlet header. The attainment of superheated steam temperatures of this value necessitates the presence of high temperature heating gases 'in contact with the superheater tubes with consequent special problems of supporting and protecting the parts in this section of the unit. The by-pass passage 36a permits the amount of heating gases contacting with the superheater to be regulated. For this purpose one or more by-pass dampers 66 are movably mounted on the header 45 and arranged to extend over the top of the passage 36a to the header 29. The' dampers 56 are externally operable in any suitable manner to control the amount of heating gases passing through the by-pass and consequently the amount passing over the superheater surface. To preserve the high thermal efficiency of the unit when the by-pass is in operation and also to prevent the control dampers 50 from becoming overheated, a pair of vertically spaced economiz- .er sections and 52 are positioned in the bypass passage. Each of these economizer sections consists of a bank of vertical flat coils of multiple-looped nested horizontal tubes arranged sideby-side and extending transversely of the tube bank 20, and as shown in Fig. 9, corresponding coils of the sections are serially connected. The lower ends of the tubes in the section 5! are connected to an external inlet header 53, while the upper ends of the tubes in the section 52 are connected to an external outlet header 54, which in turn is connected to the water space of the drum 25. The arrangement of the economizer sections transversely of the tube bank permits the tube coils to be readily inspected and renewed through access openings in the side walls of the setting and simplifies the maintenance of the sections. It also permits the headers to be outside of the setting which would not be practicable otherwise.

The gas downflow section 36 contains the main economizer divided into three superposed vertically spaced sections 60, 6 I, and 62, each of which is formed by a series of horizontally extending multiple-looped vertical flat tube coils arranged side-by-side and extending in a direction transversely of the tube bank 20. Corresponding tube coils of adjacent banks are connected as hereinafter described for a serial flow of water successively through the sections 60, 6|. and 62 in the order named. The lower ends of the tubes in the section 60 are connected to an external inlet header 63, while the upper ends of the tube coils in the section 62 are connected to an external outlet header 64. Tubes 65 connect the header 64 to the inlet header 53 of the by-pass economizer sections. With this arrangement of countercurrent flow of water relative to the heating gas flow is provided through the economizer sections 60, 6i, and 62, with a parallel flow through the by-pass economizer sections 5| and 52 in the order named but in both the water flow is generally upward. A counter-current flow through the economizer sections 60, 6i, and 62 is advantageous from the standpoint of thermal efllciency, while a parallel flow through the by-pass economizer sections 5! and 52 is advantageous in preventing the tube coils in that section from becoming steam-bound when steam is generated therein.

The described convection heated pressure parts are top supported from the external steel framework of the unit by means of U-shaped straps 66 surrounding the drum 25 and hangers 61 welded to the

tubes

30, 46 and 26. The economizer sections 66, BI and 62 are supported as shown in Figs. 2 to 'I. The tubes of the section 66 are centrally supported from below on an I-beam 'Ifl which extends between and is carried by a pair of I-beams ll extending through the side walls of the setting to the external steel work. The tube legs above the beam Ill are rigidly connected and supported from below by spacer members 12 welded to adjacent tube legs. The economizer section 60 is also supported from below at its opposite ends from the side walls of the setting, as shown in Figs. 6 to 8. The lowermost' loop of each coil has a hook-shaped bracket 13 welded thereon and engaging a rod or bar 14 resting on spaced bracket members 15 welded at spaced points to a vertically extending channel member' 16 incorporated in the corresponding side of the setting. The superjacent loops are supported from the bottom loop by dove-tail spacer connections 11, as shown in Figs. 6 and 8. Similar provisions are used for supporting the ends of the sections BI and 62 from the sides of the settime.

The upper economizer sections BI and 62 are centrally supported from below by the section 50 by the interconnecting tube portions, as shown in Figs. 4 and 5. The tube ends to be connected are joined by a coupling 18 and connected by slip hangers to the adjacent horizontally extending tubelegs. Each slip hanger consists of an inner U-shaped lug l9 welded onto the curved portion of the tube and fitting around a pin 80 removably mounted in a pair of outer U-shaped lugs 8| welded onto the straight tube portion. With this arrangement the superjacent tube coils are centrally supported by tube portions acting as short columns under compression. The economizer supporting provisions described eifectively maintain the economizer sections in their desired position, while permitting the looped ends of eachtube coil to expand and contract as a. whole relative to the end supports and independent] of one another.

Special fluid cooled supports are provided for the by-pass economizer sections and 52. As shown, each section is centrally supported from below by a group of tubes 85 extending at a slight inclination from a corresponding horizontally arranged header 86 at the front side of the wall 32 inwardly between the main economizer sections to a point beyond the tube row 44 turning upwardly parallel to the

tubes

44 and 46 and then horizontally along the top of the setting to the steam space of the drum 25. The lower horizontal portions of the tubes 85 are supported on lugs 81 carried by the

tubes

29 and 44, as shown in Figs. and 11. The portions of the tubes 85 directly below each economizer tube coil are provided with tube supporting blocks 88 welded thereon on which the lowermost legs of the economizer section rest. The upper horizontal legs of the economizer tube coils are supported centrally from the lowermost leg by spacer blocks I2 similar to the spacers for the main economizer sections. Similar supporting tubes 89 are arranged to support the looped end portions of each economizer section. Superjacent looped portions of the economizer tubes are interconnected to one another by dove-tailed spacer blocks, as shown in Fig. 8. Each of the headers 85 is connected to the water space of the drum by tubes 90 to provide a fluid circulation through the corresponding supporting

tubes

85 and 89. Support hangers 9| are connected to the upper ends of the vertical portions of the

tubes

85 and 89 to transmit the load thereon to the external supporting steel work.

As shown in Figs 2 and 0 the forward end of each superheater tube coil has an expansible of each coil will be free to expand and contract supporting connection to the supporting

tubes

44, 85, or 89. Each tube coil carries on its uppermost loop a hook member 93 engaging a bar 94 mounted on brackets 95 carried by adjacent supporting tubes. A similar arrangement is used at the opposite end of each superheater tube coil for expansibly supporting that end from the up take circulator tubes 26. The subjacent tube legs of each superheater coil section are expansibly supported from the superiacent tube legs by slip hangers of the type shown in Fig. 5. With the described arrangement the superheater tube loops closing a bank of inclined steam generating tubes,

an elevated steam and water drum, rows of uptake and downtake. circulator tubes connecting the opposite ends of said tube bank to said drum, means forming bailles dividing the space defined by 'said tube bank, circulator tube rows and drum into a plurality of gas passes including a plurality of upflow passes above said steam generating bank and a downflow pass serially connected to said upflow passes at their upper ends and arranged beyond the downtake endof said steam generating bank, a bank of steam heating tubes extending across and confined to one of said upflow passes, a sectional economizer comprising a tube bank extending across only said downfiow. pass and a second tube bank serially connected thereto and extending across only the other upflow pass, flow control damper means for the last named upflow pass arranged above said second economizer tube bank, said economizer tube banks being arranged with the tubes thereof extending transversely of said' steam generating tube bank, and means for supporting said economizer tube banks.

2. A steam generator comprising a setting enclosing a bank of inclined steam generating tubes, an elevated steam and water drum, rows of uptake and downtake circulator tubes connecting the opposite ends of said tube bank to said drum. means forming baflles dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including a wide upflow pass above the uptake end of said steam generating bank. a narrow upflow pass above the downtake end of said steam generating bank, and a downflow pass serially connected to said upflow passes at their upper ends and arranged laterally adjoining said narrow upflow pass beyond the downtake end of said steam generating bank, a bank of steam heating tubes extending second tube bank serially connected thereto and extending across only said narrow upflow-pass, flow control damper means for said narrow upflow pass arranged above said second economizer tube bank, said economizer tube bankbeing arranged with the tubes thereof extending transversely of said steam generating tube bank, and means for supporting said economizer tube banks.

3. A steam generator comprising a setting enclosing a bank of inclined steam generating tubes, a steam and water drum arranged a substantial distance above said tube bank, rows of uptake and downtake circulator tubes connecting the opposite ends of said tube bank to said drum, longitudinally spaced rows of vertically disposed fluid conduit elements having their lower ends connected to the lower end of said tube bank and their upper ends to said drum, means associated with said elements forming baflles dividing the space defined by said tube bank, circulator tube rows and drum into a' plurality of gas passes including a wide upflow pass above the uptake end of said steam generating bank, a narrow upflow pass above the downtake end of said steam generating bank, and a downflow pass serially connected to said upflow passes at' their upper ends and arranged laterally adJoining said narrow upflow pass beyond the downtake end of said steam generating bank, a bank or steam heating tubes extending across and confined to said wide upflow pass, a sectional economizer comprising a tube bank extending across only said downflow pass and a second tube bank serially connected thereto and extending across only said narrow upflow pass, fiow control damper means for said narrow upflow pass arranged above said second economizer tube bank,.

said economizer tube banks being arranged with the tubes thereof extending transversely of said steam generating tube bank and said steam heating tube bank, and means for supporting said economizer tube banks.

, 4. A steam generator comprising a setting enclosing a bank of inclined steam generating tubes, an elevated steam and water drum, rows of uptake and downtake circulator tubes connecting the uptake and downtake ends of said tube bank respectively to said drum, means dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including a pair of upflow passes, a bank of steam heating tubes extending across one of said upfiow passes, fiow control damper means for the other upflow pass, an economizer tube bank in said other upflow pass below said damper means with the tubes thereof arranged transversely oi said steam generating tube bank, and

a plurality 01 supporting tubes extending across said other upflow pass below and supporting said economizer tube bank.

5. A steam generator comprising a setting enclosing a bank or inclined steam generating tubes, an elevated steam and water drum, rows of uptake and downtake circulator tubes connecting the uptake and downtake ends of said tube, bank respective to said drum, means forming baiiles dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including a pair or upflow passes and a laterally adjoining downflow pass serially connected to said upflow passes at their upper ends, a bank of steam heating tubes extending across one of said upfiow passes, fiow control damper means for the other upflow pass, an economizer tube bank in said other upflow pass below said damper means with the pass and said other upflow pass below and sup porting said economizer tube bank and having their opposite ends connected to said drum.

6. A steam generator comprising a setting enclosing a bank of inclined steam generating tubes, a steam and water drum arranged a substantial distance above said tube bank, rows 01 uptake and downtake circulator tubes connecting the uptake and downtake ends or said tube bank respectively to said drum, longitudinally spaced rows of vertically disposedfiuid conduit elements having their lower ends connected to the lower end of said tube bank and their upper ends to said drum, means associated with said elements forming bafiies dividing the space defined by said tube bank, circulator tube rows and drum into a plurality oi-gas passes including a pair or wide and narrow upflow passes and a laterally adjoining downflow pass serially connected to said upflow passes at their upper ends, a bank or steam heating tubes extending across and confined to said wide upflow pass, flow control damper means for said narrow upflow pass, a bank or multiple-looped economizer tubes in said narrow upfiow pass below said damper means with the tubes thereof arranged transversely of said steam generating tube bank, and a plurality of supporting tubes extending across said downfiow pass and said narrow upflow pass below and supporting said economizer tube bank and having their opposite ends connected to said drum.

'7. A steam generator comprising a setting enclosing a bank of inclined steam generating tubes, a steam and water drum arranged a substantial distance above said tube bank, uptake and downtake circulator tubes connecting the opposite ends or said tube bank to said drum, longitudinally spaced rows or, vertically disposed fiuid conduit elements having their lower ends connected to the lower end or said tube bank and their upper ends of said drum, means associated with said elements forming bafiies dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including a pair or upflow passes and a laterally adjoining downflow pass serially connected to said upflow passes at their upper ends, a bank or steam heating tubes extending across and confined to one or said upfiow passes, a sectional economizer comprising a tube bank extending across only said downflow pass and a second tube bank extending across only the other upflow pass, flow control damper means for said other upflow pass arranged above said second economizer tube bank, said economizer tube banks being arranged with the tubes thereof extending transversely of said steam generating tube bank, means for supporting the ends of said first economizer tube bank at opposite sides of said setting. and a plurality of supporting tubes arranged below and supporting said second economizer tube bank and having their opposite ends connected to said drum.

8. A steam generator comprising a setting enclosing a bank of inclined steam generating tubes, a steam and water drum arranged a substantial distance above said tube bank, uptake and downtake circulator tubes connecting the opposite ends of said tube bank to said drum, longitudinally spaced rows or vertically disposed fluid conduit elements having their lower ends connected to the lower end of said tube bank and their upper ends to said drum, means associated with said elements forming baflies dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including a pair of wide and narrow upflowpasses and a laterally adjoining downflow pass serially connected to said upflow passes at their upper ends, a bank of steam heating tubes extending across and confined to said wide upflow pass, a sectional economizer comprising a tube bank extending across said downflow pass and a second tube bank extending across only said narrow upflow pass, flow control damper means for said narrow upflow pass arranged above said second economizer tube bank, said economizer tube banks being arranged with the tubes thereof extending transversely of said steam generating tube bank, means for supporting the ends of said first economizer tube bank at opposite sides of said setting, a beam support centrally of said first economizer tube bank, and a plurality of supporting tubes extendin across said downflow pass and said narrow upflow pass below and supporting said second economizer tube bank and having their opposite ends connected to said drum.

9. In a steam generator comprising a setting enclosing a bank of inclined steam generating tubes, a steam and water drum, rows of uptake and downtake circulator tubes connecting the opposite ends of said tube bank to said drum, baffle means dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including an upflow pass and a laterally adjoining downflow pass serially connected to said upflow pass at their upper ends, a bank of steam heating tubes extending across said upflow pass, and a bank of horizontally ar-' ranged multiple-looped economizer tubes arranged in said downflow pass transversely of said steain generating tube bank and circulator tube rows with their looped portions within said downflow pass, the improvement which comprises means for slideably supporting the looped portions of said economizer tube bank from said setting at opposite sides of said setting and independently' of said circulator tubes, and a beam support arranged centrally below said economizer tube bank.

10. In a steam generator comprising a setting enclosing a bank of inclined steam generatingtubes, a steam and water drum, rows of uptake and downtake circulator tubes connecting the opposite ends of said tube bank to said drum, baflie means dividing the space defined by said tube bank, circulator tube rows and drum into a plurality 01 gas passes including an upflow pass and a laterally adjoining downflow pass serially connected to said upflow pass at their upperends,

most economizer tube bank, and means including rigid tubular connectors providing a flow connection between corresponding tubes of said econo- P rt. I

a bank of steam heating tubes extending across said downflow pass transversely of said steam generating tube bank, the improvement which comprises a center beam support'ior the lower- 11. In a steam generator comprising a setting enclosing a bank of inclined steam generating tubes, a steam and water drum, rows 01 uptake and downtake circulator tubes connecting the opposite ends o'fsaidtube bank to said drum, baflie means dividing the space defined by said tube bank, circulator tube rows and drum into a plurality of gas passes including an upflow pass and a laterally adjoining downflow pass serially connected to said upflow pass at their upper ends, a bank of steam heating tubes extending across said upflow pass, and a plurality of vertically spaced serially connected banks of multiplelooped economizer tubes arranged in said downflow pass transversely of said steam. generating tube bank, the improvement which comprises means for supporting said economizer tube banks at opposite sides of said setting, a center beam support for the lowermost economizer tube bank, and means including rigid tubular connectors providing a flow connection between corresponding tubes of said economizer tube banks arranged to transmit the center load of an upper economizer tube bank to said lowermost economizer tube bank and beam support.

12. In a fluid heater comprising a setting enclosing a pass for the passage of heating gases, a plurality of vertically spaced serially connected banks of multiple-looped fluid heating tubes horizontally arranged in said pass, a center beam support for the lowermost tube bank, and means including rigid tubular connectors providing a flow connection between corresponding tubes of vertically adjacent tube banks arranged to transmit the center load of an upper bank to said lowermost bank and beam support.

13. In a fluid heater comprising a setting en-' closing a pass for thepassage of heating gases, a plurality of vertically spaced serially connected banks of multiple-looped fluid heating tubes horizontally arranged in said pass with substantially all of their looped portions within said pass,

means for slidably supporting the looped portions of said tube banks at opposite sides of said setting, a center beam support for the lowermost tube bank, and means including rigid tubular connectors providing a flow connection between corresponding tubes or vertically adjacent tube banks arranged to transmit the center load of an upper bank to said lowermost bank and beam support.

DANA H. N. MAYO.

ARTHUR E. RAYNOR.