US3364904A - Vapour generator for ship propulsion unit - Google Patents

Vapour generator for ship propulsion unit Download PDF

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Publication number
US3364904A
US3364904A US534024A US53402466A US3364904A US 3364904 A US3364904 A US 3364904A US 534024 A US534024 A US 534024A US 53402466 A US53402466 A US 53402466A US 3364904 A US3364904 A US 3364904A
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steam
gas
superheater
section
pass
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Expired - Lifetime
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US534024A
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English (en)
Inventor
Edward G Hutchings
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Babcock International Ltd
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Babcock and Wilcox Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22G—SUPERHEATING OF STEAM
    • F22G5/00—Controlling superheat temperature
    • F22G5/04—Controlling superheat temperature by regulating flue gas flow, e.g. by proportioning or diverting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B21/00—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically
    • F22B21/002—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically involving a single upper drum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B21/00—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically
    • F22B21/34—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically built-up from water tubes grouped in panel form surrounding the combustion chamber, i.e. radiation boilers
    • F22B21/341—Vertical radiation boilers with combustion in the lower part

Definitions

  • Copending application Ser. No. 399,312 filed Sept. 1964, and now Patent No. 3,280,559, provides in a ship propulsion power plant a tubulous vapour generator adapted to supply superheated vapour to an engine and to reheat the vapour between engine stages.
  • the generator has parallel gas passes leading from a furnace chamber, a first section of superheater in one pass, a reheater in a second pass and, for affording protection to the reheater when during operation vapour flow through the reheater is discontinued, damper means for controlling the flow of gases from the furnace chamber through the second pass, and a second section of superheater disposed within the second pass between the furnace chamber and the reheater.
  • the second section of the superheater exerts a cooling action on gases that may flow into the second pass when the dampers associated with that pass are closed and before such gases can reach the reheater heat exchange surfaces; moreover, with variation in the distribution of gas flow between the passes the variation in the final temperature of superheat is less than that which would occur were the whole of the superheater heat exchange surfaces to be disposed within the first pass.
  • the object of the present invention is to provide such a vapour generator or a modification of such a vapour generator in a marine power plant which is more particularly adapted to operate with an advantageous degree of 3,364,904 Patented Jan. 23, 1968 stability of superheat and advantageous superheat temperatures, while permitting with safety the use, if desired, of a relatively small amount of superheating surface upstream, as regards heating gas flow, of the reheater.
  • the present invention comprises, in a ship propulsion unit, a vapour generator adapted to supply superheated vapour to an engine and to reheat the vapour between engine stages.
  • the vapour generator includes a furnace chamber, and first and second gas passes arranged for the flow in parallel therethrough of combustion gases generated in the furnace chamber. Both a final section of a superheater and an initial or an intermediate section of the superheater are disposed in the first gas pass.
  • a reheater and, upstream as regards gas flow of the reheater, either the remaining intermediate section or the remaining initial section of the superheater are disposed in the second gas pass. Damper means are provided to proportion the flow of combustion gases between the first and second gas passes.
  • Attemperator means Disposed in a superheated vapour conduit between two superheater sect-ions subsequent in the vapour path to a superheater section in the first pass, are attemperator means capable of increased performance with increased temperature of vapour entering the attemperator means.
  • FIGURE 1 is an elevation, in section on the line II of FEGUR E 2, of a marine reheat boiler,
  • FIGURE 2 is an elevation of the boiler in section on the line 11-11 of FIGURE 1,
  • FIGURE 3 is a sectional plan view of a boiler drum to show a-ttemporator coils therein, and
  • FIGURES 4 to 6 diagrammatically illustrate certain modifications of the steam flow in relation to the tube banks in the gas passes.
  • a marine steam boiler includes a furnace chamber 1, the walls of which are lined with vapour generating tubes 2, which is flanked by first and second gas passes 3 and 4 which are upright and have gas inlets Sand 6 respectively at their lower ends.
  • the furnace chamber is formed in its roof with burner ports at positions 7 fitted with oil burners (not shown) of known atomizing types.
  • the two gas passes mentioned are both at the rear of the furnace chamber.
  • the boiler setting is divided by a transverse tube wall 8 separating the furnace cham her 1 at the front of the setting from the up-fiow passes 3 and 4 at the rear of the setting.
  • the tubes 9 in the tube wall 8 extend upwardly from a first lower header 10 initially in staggered relationship to define a screen 11 of spaced tube limbs at the entry from the furnace chamber to a space 12 below the two gas passes and then continue vertically as a single row to terminate at their upper ends in an upper header 13.
  • a second set of tubes 14 extends from the first header 10 forwardly at an upward inclination to define the floor 15 of the furnace chamber, then vertically to define the front wall 21 of the setting to an upper header 22.
  • a third set of tubes 23 extends from the first lower header 10 rearwardly at an upward inclination to define the floor 24 of the space 12, then vertically, defining the rear wall 25 of the setting to an upper header 26 in which the tubes terminate.
  • the outer side Walls 27 of the up-flow gas passes are defined by tubes 28 extending vertically from respective second and third lower headers 29 to the level of the steam and water separator drum 30 of the boiler, Where they extend in spaced relationship across respective gas outlet passages 31 and 32 from the passes 3 and 4 to discharge directly to the centrally disposed separator drum 30.
  • Further tubes 33 from the second and third lower headers extend vertically to define the side walls 34 of the furnace chamher and then extend inwardly at an upward inclination to an upper header 35, discharging to the separator drum, to define the roof 41 of the furnace chamber.
  • the various walls are suitably insulated and an outside casing 42 is provided, there being a space between the said casing and the various water walls through which combustion air may be circulated and which at the rear of the setting accommodates the superheater, reheater, and economizer headers to be mentioned.
  • the gas passes 3 and 4 are separated from one another by a tubulous wall 43 extending between the wall 8 at the front of the passes and the wall 25 at the rear of the passes.
  • the tubes of the wall extend from the second and third lower headers initially vertically in the outer sidewalls 27 and then in spaced relationship inwardly and upwardly as respective screens 44 and 45 across the gas sections and 6 of the first and second gas passes to the base of the tubulous wall 43 and then extend vertically to connect directly into the separator drum 30.
  • the gas outlet passages 31 and 32 lead to the location above the separator drum where the gases enter respective gas off-takes 46 and 47 in which respective control dampers 48 and 49 of the gas passes 3 and 4 are located.
  • the tubulous wall 43 is a membrane wall.
  • the transverse tubewall 8 and the other tubulous walls of the setting may also be membrane walls.
  • Connectors 50 lead from the upper headers 13, 22, 26 and 35 into the drum 30.
  • the superheater is in three sections connected for serial flow of vapour therethrough, of which the intermediate superheater section 51 is disposed at the lower end of the first pass and consists of a bank of horizontal, sinuous tubes extending forwardly and rearwardly across the gas pass, said bankbeing supplied from a lower steam inlet header 52 and delivering to an upper steam outlet header 53.
  • the final superheater section 61 consisting of a bank of horizontal sinuous tubes extending forwardly and reanwardly across the first gas pass, said bank being supplied from a lower steam inlet header 62 and delivering to an upper steam outer header 63.
  • an economizer section 64 formed of banks of sinuous tubes also extending forwardly and rearwardly across the gas pass, said section being supplied with water from a lower water inlet heater 65 and delivering to the drum 30.
  • the heat exchange tubes in the second gas pass similarly extend forwardly and rearwardly and comprise the sinuous tubes of the initial superheater section 66 disposed at the bottom of the gas pass and sinuous nested tubes of reheater tube banks 67 above the initial superheater section.
  • the initial superheater section receives steam through a lower steam inlet header 68 and delivers to an upper steam outlet header 69.
  • the reheater 67 receives steam from an upper steam inlet header 70 and delivers to a lower steam outlet header 71.
  • the separator drum may be provided internally thereof with cyclone separators (not shown) suitable downcomers 72 extend from the end lengths of the drum and are provided for supplying water to the first, second and third lower headers and 29.
  • the initial, intermediate and final superheater sections are connected for serial flow of steam therethrough.
  • a steam conduit 73 having an attemperator 74 therein.
  • the attemperator comprises a heat exchanger 81 in a steam path 82 controlled by a valve 83 and a bypass steam path 84 in parallel with the path 82 and controlled by a valve 85.
  • the heat exchanger 81 is formed by a plurality of coils in loop form connected for the flow of steam therethrough in parallel and externally cooled by boiler water.
  • the coils may extend as shown in FIGURE 3 within the water space of the drum 30 or they may extend within a vessel separate from the drum 30 but provided with connections to the boiler so that the coils may be cooled by boiler water.
  • combustion gases generated in the furnace chamber 1 by the combustion of fuel oil delivered in atomized spray form by the burners in the furnace chamber roof 41 leave the bottom of the furnace chamber, enter-the space 12 below the two gas passes 3 and 4 and flow in parallel gas streams upwardly through the two gas passes.
  • Water to be delivered to the drum 30 to maintain the Water level therein is first heated in the economizer 64. Steam is generated in the various floor, screen and Wall tubes and passes with water into the drum in which steam and water separation is effected with the aid of cyclone separators (not shown).
  • the downcomers 72 take water from the drum to supply the various steam-generating tubes.
  • a conduit (not shown) takes steam from the drum to the first superheater section 66. After passing through the first superheater section, the steam is led by another conduit (not shown) to the intermediate superheater section 51. After passing through the intermediate superheater section, the steam is led by the conduit 73 through the attemperator 74 comprising the attemperator coils 81 in the drum 30 together with the attemperator coil bypass 84, to the final superheater section 64. Afterpassing through the final superheater section the steam is led to the high pressure stage of the ahead turbine. After expansion in the said turbine stage, the steam is led to the reheater 67. After passing through the reheater it is led to the low pressure stage of the ahead turbine for further expansion therein.
  • the dampers 48 and 49 are adjusted relative to one another so as to proportion the total gas flow between the first and second pass that the temperature of the re heated steam has the desired value.
  • the necessary gas flow proportioning is achieved by partially closing the dampers 48 of the first pass with the dampers 49 of the second pass fully open, or by partially closing the dampers 49 of the second pass with the dampers 48 of the first pass fully open.
  • the initial superheater section 66 would be less greatly heated while the intermediate and final superheater sections 51 and 61 would be more greatly heated. Since the initial superheater section 66 has a heat exchange area which is limited in order that the reheater 67 may readily receive adequately hot gases in normal operations, the reduction in heat absorption in the primary superheater section will be less than the increase in heat absorption by the intermediate and final superheater sections 51 and 61; however, more heat will be abstracted from the steam by the attemperator 74 which receives hotter steam and therefore the final steam temperatiire may not greatly vary.
  • the furnace chamber 1 is fired to generate the required amount of steam at the required pressure while the dampers 49 of the second gas pass 4 are closed.
  • the initial superheater section 66 is traversed by saturated or low temperature steam on its way to the intermediate superheater section 51 and by cooling any gases that may flow from the space 12 into the second gas pass 4 it protects the reheater 67, in which no steam is flowing.
  • the capacity of the attemperator coils 81 and the settings of the valves 83 and 85, the gas flow path areas and the disposition of the superheater tubes in the gas passes will be chosen in relation to one another so that the reheater may be adequately heated, and so that the reheat temperature may be regulated as described and the superheat temperature may be stabilized with a restriction on it maximum under the conditions for astern operation.
  • a further indirect-contact-type attemperator having fixed valve setting may be placed in the steam conduit from the final superheater section, which attemperator will further restrict temperature variations.
  • the superheat temperature may be controllably regallated if desired with the aid of a spray-type attemperator which is disposed in the steam conduit from the final superheater section and which is automatically controlled in dependance upon the temperature in the conduit subsequent thereto.
  • a spray-type attemperator which is disposed in the steam conduit from the final superheater section and which is automatically controlled in dependance upon the temperature in the conduit subsequent thereto.
  • the capacity of said attemperator may be relatively small.
  • the use of two attemperators does not lead to control difiiculties if, as envisaged, the indirect-contact-type attemperator 74 is normally used with pre-set fixed valve settings.
  • the superheat temperature may be regulated with the aid of gas bypass to the first and second gas passes.
  • a third upflow gas pass 101 which is separated from the first and second gas passes by respective partition walls and in which the gas flow is controllable by the operation of dampers 102.
  • heat exchange means 103 may be provided therein which may be economizer or steam generating surfaces.
  • the steam in each of the superheater sections flows generally upwardly therein, that is to say, in parallel flow with the gas passing over the section.
  • the steam may be led through any or all of the superheater sections in counterflow to the gas.
  • FIGURE 5 indicates a modification in which the initial superheater section 66 is placed in the second gas pass 4 below the reheater 67 and the intermediate superheater section 51 is placed in the first gas pass 3 below the economizer 64 and above the final superheater section 61; the attemperator 74 is placed in the steam flow between the intermediate and final superheater sections.
  • FIGURE 6 indicates a modification in which the initial superheater section 66 is placed in the first gas pass 3 be low the economizer 64 and above the final superheater section 61 and the intermediate superheater section 51 is placed in the second gas pass 4 below the reheater 67; the attemperator 74 is placed in steam fiow between the initial and intermediate superheater sections. Alternatively, it may be satisfactory to place the attemperator in the steam flow between the intermediate and final superheater sections.
  • the final superheater section is placed in the first gas pass below the economizer and above the initial superheater section and the intermediate superheater section is placed in the second gas pass below the reheater; the attemperator is placed in the steam flow between the initial and intermediate superheater sections or in the steam flow between the intermediate and final superheater sections.
  • heat exchange surfaces additional to those mentioned may be incorporated as may be suitable in view of the gas temperatures to be expected, the designed duty of the boiler and the space available.
  • economizer surface maybe placed in the second gas pass above the reheater, or, as indicated in the boiler specifically described in the aforementioned copending application, an initial reheating tube bank may be placed in a common gas passage above the dampers or, alternatively or in addition, economizer surface might be placed in such common gas passage.
  • Vapour generator comprising walls defining a furnace chamber, means for burning fuel in said furnace chamber to produce high temperature heating gases, means defining a first gas pass connected for the flow therethrough of high temperature gases from said furnace chamber, means defining a second gas pass con nected for the flow therethrough of high temperature gases from said furnace chamber, damper means arranged to regulate the flow of heating gases through said first and second gas passes, a pair of superheater sections disposed in said first gas pass, an additional superheater section and a reheater section disposed in said second gas pass, said additional superheater section being arranged upstream of said heheater section with respect to gas flow through said second gas pass, vapour conducting conduits connecting the three mentioned superheater sections for serial flow of vapour therethrough, the three mentioned superheater sections
  • said attemperator means includes a heat exchanger, means for passing liquid from said vapour generator in heat exchange relation with the vapour flowing through said heat exchanger, and means for by-passing vapour around said heat exchanger.
  • the means for regulating the vapour temperature leaving the final superheater section includes a vapour conducting conduit for passage of vapour from said final superheater section, and means for spraying liquid directly into the vapour passing through the last mentioned conduit.
  • the invention according to claim 2 further including means defining a third gas pass connected for the controllable flow therethrough of high temperature gases from said furnace chamber, said third gas pass being arranged in parallel flow relation with said first and second gas passes to enable by-passing of gases around said first and second gas passes.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
US534024A 1965-03-15 1966-03-14 Vapour generator for ship propulsion unit Expired - Lifetime US3364904A (en)

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GB10925/65A GB1140036A (en) 1965-03-15 1965-03-15 Improvements in vapour generating and superheating units in ship propulsion power plant

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GB (1) GB1140036A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
SE (1) SE327153B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3602201A (en) * 1968-09-23 1971-08-31 Babcock & Wilson Ltd Vapor generator
US20170001871A1 (en) * 2014-01-06 2017-01-05 Zhongying Changjiang International New Energy Investment Co., Ltd. Device and method for producing nano silica materails from pyrolysis of biomass
US20180328583A1 (en) * 2017-05-15 2018-11-15 General Electric Company Boiler and modifying method thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3048017A (en) * 1958-12-26 1962-08-07 Babcock & Wilcox Ltd Steam turbine power plant
US3280559A (en) * 1963-09-26 1966-10-25 Babcock & Wilcox Ltd Ship propulsion power plant

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3048017A (en) * 1958-12-26 1962-08-07 Babcock & Wilcox Ltd Steam turbine power plant
US3280559A (en) * 1963-09-26 1966-10-25 Babcock & Wilcox Ltd Ship propulsion power plant

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3602201A (en) * 1968-09-23 1971-08-31 Babcock & Wilson Ltd Vapor generator
US20170001871A1 (en) * 2014-01-06 2017-01-05 Zhongying Changjiang International New Energy Investment Co., Ltd. Device and method for producing nano silica materails from pyrolysis of biomass
US20180328583A1 (en) * 2017-05-15 2018-11-15 General Electric Company Boiler and modifying method thereof
US11015801B2 (en) * 2017-05-15 2021-05-25 General Electric Company Boiler and modifying method thereof

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SE327153B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1970-08-10
GB1140036A (en) 1969-01-15

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