US20130048245A1 - Heat Exchanger Having Improved Drain System - Google Patents
Heat Exchanger Having Improved Drain System Download PDFInfo
- Publication number
- US20130048245A1 US20130048245A1 US13/697,070 US201113697070A US2013048245A1 US 20130048245 A1 US20130048245 A1 US 20130048245A1 US 201113697070 A US201113697070 A US 201113697070A US 2013048245 A1 US2013048245 A1 US 2013048245A1
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- Prior art keywords
- drain
- headers
- manifold
- heat exchanger
- pipes
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/06—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits having a single U-bend
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- 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
- F22B21/02—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically built-up from substantially straight water tubes
- F22B21/12—Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically built-up from substantially straight water tubes involving two or more upper drums and two or more lower drums, e.g. with crosswise-arranged water-tube sets in abutting connections with drums
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B37/00—Component parts or details of steam boilers
- F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
- F22B37/48—Devices for removing water, salt, or sludge from boilers; Arrangements of cleaning apparatus in boilers; Combinations thereof with boilers
- F22B37/50—Devices for removing water, salt, or sludge from boilers; Arrangements of cleaning apparatus in boilers; Combinations thereof with boilers for draining or expelling water
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F17/00—Removing ice or water from heat-exchange apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/26—Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F2265/00—Safety or protection arrangements; Arrangements for preventing malfunction
- F28F2265/06—Safety or protection arrangements; Arrangements for preventing malfunction by using means for draining heat exchange media from heat exchangers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/0246—Arrangements for connecting header boxes with flow lines
Definitions
- This invention relates in general to heat exchangers and more particularly to a heat exchanger having an improved drain system, to the drain system itself; and to a heat recovery steam generator containing the heat exchanger.
- HRSGs Heat recovery steam generators
- the typical HRSG includes multiple heat exchangers located one after the other in the flow of hot exhaust gases from a gas turbine.
- heat exchangers are an economizer for elevating the temperature of feed water, an evaporator for converting the high temperature water discharged by the economizer into saturated steam, and a superheater for converting the saturated steam into superheated steam.
- Many HRSGs have more than one economizer, evaporator, and superheater operating at different pressures.
- An economizer operates with a full charge of water. Indeed, it simply heats the water so that the evaporator to which it is connected consumes less heat converting the water to saturated steam.
- the superheater contains only steam during operation of the HRSG, but when the HRSG is taken off line and shut down, the steam within the superheater condenses and water collects in its lower regions. From time to time, economizers and superheaters require servicing, and many service procedures involve draining the water that remains in those components. Likewise, some HRSGs operate in environments that experience temperatures below the freezing temperature of water. When those HRSGs are taken out of service, the economizers and superheaters should be drained to prevent water from freezing in them. Hence, the economizers and superheaters have drain systems at their lower regions for removing water from them.
- Every HRSG includes a duct-like structure, called a casing, having an inlet and an outlet.
- Hot gas from a gas turbine or other source enters the casing at the inlet and flows through the casing, discharging at the outlet.
- the gas encounters at least one superheater, at least one evaporator, and an economizer, generally in that order with respect to the flow of the gas. While some of the components of the drain systems for both the economizer and the superheater exist within the casing, the remaining components lie outside the casing.
- Economizers and superheaters include coils that can consist of multiple rows of tubes, with the tube rows being arranged one after the other in the flow of hot gases ( FIG. 2 ).
- the tubes are connected to a lower header that extends horizontally and also transversely with respect to the gas flow.
- the lower headers facilitate circulation through the coil and enable it to be drained.
- Drain piping cannot be connected directly between headers because water will transfer from header to header without passing through the tubes. This bypass from tube row to tube row to row will diminish the coil performance.
- each coil requires drain piping that includes numerous small bore pipes and fittings, both internal of the HRSG casing and external to it as well. The latter require penetration seals in the floor of the casing.
- the typical coil ( FIG. 2 ) has a drain pipe leading away from each lower header, through the casing to a valve located outside of the casing. Beyond its valve, each drain pipe opens into a drain manifold also located external to the casing, and it contains a common drain valve to provide redundancy. This requires multiple penetrations of the casing, and each penetration requires a seal that is welded to the pipe and to the floor of the casing. It also requires making welds within the confines of the casing where each drain pipe connects with its lower header. More welds are required externally of the casing at couplings and elbows in the drain pipes as well as at the valve in each drain pipe.
- FIG. 1 is a longitudinal sectional view of a heat recovery steam generator having heat exchangers constructed in accordance with and embodying the present invention
- FIG. 2 is a perspective view of a drain system for a prior art heat exchanger
- FIG. 3 is a perspective view of a coil for the heat exchanger of the present invention.
- FIG. 4 is a sectional view of the coil shown in FIG. 3 ;
- FIG. 5 is a perspective view of the drain system for the heat exchanger of the present invention.
- FIG. 6 is another perspective view of the drain system for the heat exchanger.
- a heat recovery steam generator (HRSG) A includes a casing 2 , which is essentially a large duct having an inlet 4 and an outlet 6 . Between the inlet 4 and the outlet 6 the casing 2 has a floor 8 that supports several heat exchangers for converting subcooled water into superheated steam.
- a hot gas typically the exhaust of a gas- or oil-fired turbine, enters the casing 2 at its inlet 4 , passes through the several heat exchangers which extract heat from it, and leaves through the outlet 6 at a substantially reduced temperature.
- an economizer 12 for bringing subcooled water, which might be the condensate from a steam turbine, to a higher temperature
- an evaporator 14 for converting the heated subcooled water derived from the economizer 12 to saturated steam
- a superheater 16 for converting the saturated steam to superheated steam.
- the HRSG may have more than one economizer 12 , evaporator 14 and superheater 16 organized in groups that operate at different pressures. Each group has a pump located before or after its economizer 12 , and that pump controls the pressures at which the group operates.
- the superheater 16 precedes the evaporator 14 and the evaporator 14 precedes the economizer 12 .
- the economizer 12 and the superheater 16 will retain water when the HRSG
- the economizer 12 includes ( FIGS. 3 & 4 ) a coil 18 that is located in the casing 2 and a drain system 20 that is located below the coil 18 and for the most part inside the casing 2 .
- the coil 18 has tubes 22 that extend vertically and are organized in multiple rows 24 that extend transversely with respect to the flow of gas through the casing 2 .
- the coil 18 has a supply header 26 that extends over the row 24 of tubes 22 located downstream in the flow of the exhaust gas through the coil 18 and is provided with an inlet port 28 .
- a discharge header 30 extends over the tubes 22 , and it has an outlet port 32 .
- the supply header 26 connects with and opens into the upper end of every other tube 22 of the endmost downstream row 24 .
- the remaining tubes 22 of the endmost downstream row 24 connect with the upper ends of adjacent tubes 22 , that is to say with every other tube 22 , in the next row 24 through U-shaped transitions 34 .
- the upper ends of the remaining tubes 22 in the next row are connected at their upper ends to the upper ends of adjacent tubes 22 in the next row 24 upstream from it through still more transitions 34 .
- the same pattern of transitions 34 at the upper ends of the tubes 22 continues through the coil 18 to the discharge header 30 . There the upper end of every other tube 22 in the next to endmost row 24 and the upper ends of all of the tubes 22 in the endmost row 24 open into the discharge header 30 .
- each lower header 36 has a drain port 38 .
- Subcooled water such as the condensate from a steam turbine, enters the coil 18 at the inlet port 28 of its supply header 26 .
- the header 28 distributes the water to every other tube 23 of the endmost downstream row 24 through which it flows downwardly into the lower header 36 to which those tubes 22 are connected.
- the water rises out of the lower header 36 at the remaining tubes 22 of the endmost row 24 .
- the water flows into every other tube 22 of the next row 24 through the U-shaped transitions 34 that connect those tubes 22 .
- the water circulates through the coil 18 from one row 24 to the next in a like manner and at the endmost upstream rows enters the discharge header 30 . It leaves the header 30 at the outlet port 32 and flows on to the evaporator 14 . As the water circulates through the coil 18 its temperature increases, but even so it leaves the discharge port 32 in a subcooled condition.
- the lower headers 36 lie above the floor 8 of the casing 2 , while the drain system 20 for the most part occupies the space between the lower headers 36 and the floor 8 .
- the drain system 20 includes ( FIGS. 5 & 6 ) drain pipes 40 that extend downwardly from the discharge ports 38 , to which they are connected, and then transition horizontally.
- each drain pipe 40 has a generally upright segment 42 and a generally horizontal segment 44 .
- the discharger ports 38 are located near the ends of their respective headers 36 , with the ports 38 for alternating headers 36 being located at opposite ends of those headers 36 .
- the horizontal segments 44 of the drain pipes 40 for alternating headers 36 approach the bottom center of the coil 18 from opposite directions.
- the drain pipes 40 are provided with check valves 48 that are oriented such that water will flow through the drain pipes 40 to the manifold 46 , but not in the opposite direction.
- the check valves 48 which may be located in either the upright segments 42 or the horizontal segments 44 , allow water to drain from the coil 18 and lower headers 36 when the manifold 46 is opened, but prevent water from circulating from header 36 to header 36 through the drain system 20 and thus bypassing the tubes 22 .
- all of the drain pipes 40 should contain a check valve 48 , except the drain pipe 40 that connects with the endmost header 36 at the downstream end of the coil 18 .
- That drain pipe 40 need not contain a check valve 48 , although it may.
- Each check valve 48 should open under a low head, that is to say with a small pressure differential across it. Preferably it should take the form of a swing-type valve. If a check valve 48 does not close completely, only minor bypassing from header 36 to header 36 will occur.
- the drain manifold 48 has a common drain port 50 that opens downwardly. All that resides above it, including the tubes 22 , the headers 26 , 30 , 36 as well as the drain pipes 40 , the check valves 48 and the drain manifold 46 , may be assembled in a shop and shipped as a unit to the site where the HRSG A is assembled. This includes most of the drain system 20 . Contrast this with a conventional heat exchanger where the drains and their valves are installed at the site of the HRSG at considerable expense and inconvenience.
- the drain port 50 of the drain manifold 46 is connected to a common drain line 52 that extends downwardly from the manifold 46 and penetrates the floor 8 of the casing 2 at a single seal 54 .
- the drain line 52 contains two drain valves 56 arranged in succession, with the last of the two providing redundancy. This eliminates the congestion of piping found below the floors of casings for HRSGs equipped with traditional drain systems.
- the coil 18 with the improved drain system 20 serves as the economizer 12 in the HRSG A
- the coil 18 and its drain system 20 may be used on other heat exchangers having multiple lower headers 36 in which water may collect.
- the superheater 16 while in operation contains only steam, but when taken out of operation, that steam may condense and occupy the lower regions of its tubes 22 and lower headers 36 .
- the superheater 16 may take the form of the coil 18 , although with fewer tubes 22 and lower headers 36 , and may have the improved drain system 20 .
- a feedwater heater to the extent that it may differ from an economizer, could be furnished with the drain system 20 .
Abstract
A heat recovery steam generator (HRSG) (A) has a casing (2) and several heat exchangers in the casing. Some of those heat exchangers (12,16) take the form of coils (18) having multiple lower headers (36) into which the lower ends of tubes (18) open. The tubes (18) and headers (36) hold or may hold water and need to be drained from time to time. To this end, the heat ex changer (12,16) has a drain system (20) provided with drain pipes (40) that are connected to the lower headers (36) and contain check valves (48) that permit the water to flow away from the headers (36), but not into them. The drain pipes (40) lead to and open into a drain manifold (46). The drain pipes (40), check valves (48) and drain manifold (46) are assembled in a shop along with the coil (18) and, when the HRSG (A) is assembled in the field, lie within the interior of the casing (2). The drain system (20) also includes a single common drain line (52) that extends downwardly from the drain manifold (46) and through the floor (8) of the casing (2), beyond which it is provided with a drain valve (56) that, when opened, allows water to drain from the coil (18).
Description
- This application derives priority from and otherwise claims the benefit of U.S. provisional application 61/346742 filed May 20, 2010, which is incorporated herein by reference.
- This invention relates in general to heat exchangers and more particularly to a heat exchanger having an improved drain system, to the drain system itself; and to a heat recovery steam generator containing the heat exchanger.
- The gas turbines that power electrical generators discharge exhaust gases at extremely high temperatures. Heat recovery steam generators (HRSGs) extract the heat from the gases to produce steam that powers steam turbines that in turn drive more electrical generators.
- The typical HRSG includes multiple heat exchangers located one after the other in the flow of hot exhaust gases from a gas turbine. Among heat exchangers are an economizer for elevating the temperature of feed water, an evaporator for converting the high temperature water discharged by the economizer into saturated steam, and a superheater for converting the saturated steam into superheated steam. Many HRSGs have more than one economizer, evaporator, and superheater operating at different pressures.
- An economizer operates with a full charge of water. Indeed, it simply heats the water so that the evaporator to which it is connected consumes less heat converting the water to saturated steam. The superheater contains only steam during operation of the HRSG, but when the HRSG is taken off line and shut down, the steam within the superheater condenses and water collects in its lower regions. From time to time, economizers and superheaters require servicing, and many service procedures involve draining the water that remains in those components. Likewise, some HRSGs operate in environments that experience temperatures below the freezing temperature of water. When those HRSGs are taken out of service, the economizers and superheaters should be drained to prevent water from freezing in them. Hence, the economizers and superheaters have drain systems at their lower regions for removing water from them.
- Every HRSG includes a duct-like structure, called a casing, having an inlet and an outlet. Hot gas from a gas turbine or other source enters the casing at the inlet and flows through the casing, discharging at the outlet. Within the casing the gas encounters at least one superheater, at least one evaporator, and an economizer, generally in that order with respect to the flow of the gas. While some of the components of the drain systems for both the economizer and the superheater exist within the casing, the remaining components lie outside the casing.
- Economizers and superheaters include coils that can consist of multiple rows of tubes, with the tube rows being arranged one after the other in the flow of hot gases (
FIG. 2 ). Within each row of tubes the tubes are connected to a lower header that extends horizontally and also transversely with respect to the gas flow. The lower headers facilitate circulation through the coil and enable it to be drained. Drain piping cannot be connected directly between headers because water will transfer from header to header without passing through the tubes. This bypass from tube row to tube row to row will diminish the coil performance. But each coil requires drain piping that includes numerous small bore pipes and fittings, both internal of the HRSG casing and external to it as well. The latter require penetration seals in the floor of the casing. - The typical coil (
FIG. 2 ) has a drain pipe leading away from each lower header, through the casing to a valve located outside of the casing. Beyond its valve, each drain pipe opens into a drain manifold also located external to the casing, and it contains a common drain valve to provide redundancy. This requires multiple penetrations of the casing, and each penetration requires a seal that is welded to the pipe and to the floor of the casing. It also requires making welds within the confines of the casing where each drain pipe connects with its lower header. More welds are required externally of the casing at couplings and elbows in the drain pipes as well as at the valve in each drain pipe. And of course still more welds are required to join each drain pipe to the drain manifold into which it opens. All of this work takes place in the field where the HRSG is assembled, not in the shop where the coil is manufactured, and much of it requires workman to perform their tasks in extremely confined spaces. -
FIG. 1 is a longitudinal sectional view of a heat recovery steam generator having heat exchangers constructed in accordance with and embodying the present invention; -
FIG. 2 is a perspective view of a drain system for a prior art heat exchanger; -
FIG. 3 is a perspective view of a coil for the heat exchanger of the present invention; -
FIG. 4 is a sectional view of the coil shown inFIG. 3 ; -
FIG. 5 is a perspective view of the drain system for the heat exchanger of the present invention; and -
FIG. 6 is another perspective view of the drain system for the heat exchanger. - Referring now to the drawings (
FIG. 1 ), a heat recovery steam generator (HRSG) A includes acasing 2, which is essentially a large duct having aninlet 4 and anoutlet 6. Between theinlet 4 and theoutlet 6 thecasing 2 has afloor 8 that supports several heat exchangers for converting subcooled water into superheated steam. A hot gas, typically the exhaust of a gas- or oil-fired turbine, enters thecasing 2 at itsinlet 4, passes through the several heat exchangers which extract heat from it, and leaves through theoutlet 6 at a substantially reduced temperature. Among the heat exchangers are aneconomizer 12 for bringing subcooled water, which might be the condensate from a steam turbine, to a higher temperature, anevaporator 14 for converting the heated subcooled water derived from theeconomizer 12 to saturated steam, and asuperheater 16 for converting the saturated steam to superheated steam. The HRSG may have more than oneeconomizer 12,evaporator 14 andsuperheater 16 organized in groups that operate at different pressures. Each group has a pump located before or after itseconomizer 12, and that pump controls the pressures at which the group operates. In terms of the flow of gas through thecasing 2, for any group thesuperheater 16 precedes theevaporator 14 and theevaporator 14 precedes theeconomizer 12. Theeconomizer 12 and thesuperheater 16 will retain water when the HRSG - A is not in operation, and this water can interfere with maintenance procedures. Moreover, if the HRSG A is subjected to freezing temperatures, the retained water can freeze and damage the
economizer 12 andsuperheater 16. - Using the
economizer 12 as an example, it includes (FIGS. 3 & 4 ) acoil 18 that is located in thecasing 2 and adrain system 20 that is located below thecoil 18 and for the most part inside thecasing 2. Thecoil 18 hastubes 22 that extend vertically and are organized inmultiple rows 24 that extend transversely with respect to the flow of gas through thecasing 2. Above thetubes 22 thecoil 18 has asupply header 26 that extends over therow 24 oftubes 22 located downstream in the flow of the exhaust gas through thecoil 18 and is provided with aninlet port 28. At theupstream rows 24 of tubes, adischarge header 30 extends over thetubes 22, and it has anoutlet port 32. Thesupply header 26 connects with and opens into the upper end of everyother tube 22 of the endmostdownstream row 24. Theremaining tubes 22 of the endmostdownstream row 24 connect with the upper ends ofadjacent tubes 22, that is to say with everyother tube 22, in thenext row 24 throughU-shaped transitions 34. The upper ends of theremaining tubes 22 in the next row are connected at their upper ends to the upper ends ofadjacent tubes 22 in thenext row 24 upstream from it through stillmore transitions 34. The same pattern oftransitions 34 at the upper ends of thetubes 22 continues through thecoil 18 to thedischarge header 30. There the upper end of everyother tube 22 in the next toendmost row 24 and the upper ends of all of thetubes 22 in theendmost row 24 open into thedischarge header 30. The lower ends of thetubes 22 open intolower headers 36 that extend transversely with respect to the flow of gas, there being a separatelower header 36 for eachrow 24, except at the upstream end where a singlelower header 36 services the two endmostupstream rows 24. Eachlower header 36 has adrain port 38. - Subcooled water, such as the condensate from a steam turbine, enters the
coil 18 at theinlet port 28 of itssupply header 26. Theheader 28 distributes the water to every other tube 23 of the endmostdownstream row 24 through which it flows downwardly into thelower header 36 to which thosetubes 22 are connected. The water rises out of thelower header 36 at the remainingtubes 22 of theendmost row 24. The water flows into everyother tube 22 of thenext row 24 through theU-shaped transitions 34 that connect thosetubes 22. The water circulates through thecoil 18 from onerow 24 to the next in a like manner and at the endmost upstream rows enters thedischarge header 30. It leaves theheader 30 at theoutlet port 32 and flows on to theevaporator 14. As the water circulates through thecoil 18 its temperature increases, but even so it leaves thedischarge port 32 in a subcooled condition. - The
lower headers 36 lie above thefloor 8 of thecasing 2, while thedrain system 20 for the most part occupies the space between thelower headers 36 and thefloor 8. Thedrain system 20 includes (FIGS. 5 & 6 )drain pipes 40 that extend downwardly from thedischarge ports 38, to which they are connected, and then transition horizontally. Thus, eachdrain pipe 40 has a generallyupright segment 42 and a generallyhorizontal segment 44. Thedischarger ports 38 are located near the ends of theirrespective headers 36, with theports 38 for alternatingheaders 36 being located at opposite ends of thoseheaders 36. Thus, thehorizontal segments 44 of thedrain pipes 40 for alternatingheaders 36 approach the bottom center of thecoil 18 from opposite directions. Here they open into acommon drain manifold 46 that extends horizontally beneath theheaders 36. Thedrain pipes 40 are provided withcheck valves 48 that are oriented such that water will flow through thedrain pipes 40 to the manifold 46, but not in the opposite direction. Thecheck valves 48, which may be located in either theupright segments 42 or thehorizontal segments 44, allow water to drain from thecoil 18 andlower headers 36 when the manifold 46 is opened, but prevent water from circulating fromheader 36 toheader 36 through thedrain system 20 and thus bypassing thetubes 22. Actually, all of thedrain pipes 40 should contain acheck valve 48, except thedrain pipe 40 that connects with theendmost header 36 at the downstream end of thecoil 18. Thatdrain pipe 40 need not contain acheck valve 48, although it may. Eachcheck valve 48 should open under a low head, that is to say with a small pressure differential across it. Preferably it should take the form of a swing-type valve. If acheck valve 48 does not close completely, only minor bypassing fromheader 36 toheader 36 will occur. - The
drain manifold 48 has acommon drain port 50 that opens downwardly. All that resides above it, including thetubes 22, theheaders drain pipes 40, thecheck valves 48 and thedrain manifold 46, may be assembled in a shop and shipped as a unit to the site where the HRSG A is assembled. This includes most of thedrain system 20. Contrast this with a conventional heat exchanger where the drains and their valves are installed at the site of the HRSG at considerable expense and inconvenience. - Once the
coil 18 is set onto thefloor 8 of thecasing 2, at the site where the HRSG is assembled, a few additional procedures complete thedrain system 20. To this end, thedrain port 50 of thedrain manifold 46 is connected to acommon drain line 52 that extends downwardly from the manifold 46 and penetrates thefloor 8 of thecasing 2 at asingle seal 54. Below thecasing 2 thedrain line 52 contains twodrain valves 56 arranged in succession, with the last of the two providing redundancy. This eliminates the congestion of piping found below the floors of casings for HRSGs equipped with traditional drain systems. - While the
coil 18 with theimproved drain system 20 serves as theeconomizer 12 in the HRSG A, thecoil 18 and itsdrain system 20 may be used on other heat exchangers having multiplelower headers 36 in which water may collect. For example, thesuperheater 16, while in operation contains only steam, but when taken out of operation, that steam may condense and occupy the lower regions of itstubes 22 andlower headers 36. Thesuperheater 16 may take the form of thecoil 18, although withfewer tubes 22 andlower headers 36, and may have the improveddrain system 20. Also, a feedwater heater, to the extent that it may differ from an economizer, could be furnished with thedrain system 20.
Claims (18)
1. A heat exchanger comprising:
tubes arranged generally vertically;
lower headers into which the lower ends of the tubes open;
drain pipes connected to the lower headers and extending downwardly from the lower headers; and
check valves in at least some of the drain pipes where they are oriented to allow flow out of the lower headers, but not substantially into the lower headers.
2. A heat exchanger according to claim 1 and further comprising a drain manifold located below the lower headers, the drain pipes being connected beyond their check valves to the drain manifold.
3. A heat exchanger according to claim 2 wherein each drain pipe has a generally upright segment that is connected to one of the lower headers and a generally horizontal segment that is connected to the drain manifold.
4. A heat exchanger according to claim 3 wherein the lower headers are generally parallel, and the horizontal segments of the drain pipes are generally parallel to the lower headers; and wherein the drain manifold extends generally transversely with respect to the lower headers.
5. A heat exchanger according to claim 4 wherein the drain pipes connect with the lower headers beyond the drain manifold, with the drain pipes for adjacent headers being on opposite sides of the drain manifold.
6. A heat exchanger according to claim 4 wherein the tubes are organized in rows, with the lower ends of the tubes for at least some of the rows opening into separate lower header.
7. A heat exchanger according to claim 6 wherein the upper ends of some of the tubes in one row that is endmost open into a supply header;
and wherein the tubes of another row that is endmost at their upper ends open into a discharge headers.
8. A heat exchanger according to claim 4 and further comprising:
a common drain line connected to the drain manifold and extending downwardly from it, and
a drain valve in the common drain line.
9. A heat exchanger according to claim 8 and further comprising water in the lower headers, the drain pipes, the drain manifold and the common drain line ahead of the drain valve.
10. A heat recovery steam generator comprising:
a casing having an inlet and an outlet and also a floor between the inlet and outlet; and
the heat exchanger of claim 1 located in the casing with its drain pipes and check valves being located above the floor.
11. A heat recovery steam generator comprising:
a casing having an inlet and an outlet and also a floor between the inlet and outlet; and
the heat exchanger of claim 4 located in the casing with its drain pipes and check valves and drain manifold being located above the floor;
a common drain line connected to the drain manifold and extending downwardly through the floor of the casing; and
a drain valve located in the common drain line and being outside of the casing.
12. A heat recovery steam generator according to claim 11 wherein the drain pipes connect with the lower headers beyond the drain manifold, with the drain pipes for adjacent headers being on opposite sides of the drain manifold.
13. A heat exchanger comprising:
a coil including:
tubes extending vertically and organized in rows; and
lower headers into which the tubes at their lower ends open; and
a drain system including;
drain pipes connected to the lower headers and extending downwardly from them;
a drain manifold into which the drain pipes open; check valves in at least some of the drain pipes and oriented to allow flow from the headers to the drain manifold but not in the opposite direction;
a common drain line extending downwardly from the drain manifold; and
a valve in the common drain line.
14. A heat exchanger according to claim 13 wherein the tubes of the rows open into a separate lower header.
15. A heat exchanger according to claim 13 wherein each drain pipe includes an upright segment and a horizontal segment.
16. A heat exchanger according to claim 15
wherein the drain manifold extends transversely with respect to the lower headers;
wherein the drain pipes open into the drain manifold at their horizontal segments; and
wherein the drain pipes are connected to the lower headers at their upright segments on opposite sides of the drain manifold, with the upright segments of the drain pipes for adjacent lower headers being on opposite sides of the drain manifold.
17. A drain system for a heat exchanger having lower headers arranged side by side, said drain system comprising:
drain pipes extending downwardly from the lower headers and then generally horizontally;
a drain manifold into which the drain pipes open, the drain manifold extending generally transversely with respect to the drain pipes;
check valves in the drain pipes and being oriented to allow fluid to flow out of the headers into the drain manifold, but not in the opposite direction into the headers;
a drain line extending downwardly from the drain manifold; and
a drain valve in the drain line.
18. A drain system according to claim 17 wherein the drain pipes are connected to the headers near the ends of the headers, and the drain pipes for adjacent headers are at opposite ends of those headers.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US13/697,070 US20130048245A1 (en) | 2010-05-20 | 2011-05-13 | Heat Exchanger Having Improved Drain System |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US34674210P | 2010-05-20 | 2010-05-20 | |
US13/697,070 US20130048245A1 (en) | 2010-05-20 | 2011-05-13 | Heat Exchanger Having Improved Drain System |
PCT/US2011/036429 WO2011146333A2 (en) | 2010-05-20 | 2011-05-13 | Heat exchanger having improved drain system |
Publications (1)
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US20130048245A1 true US20130048245A1 (en) | 2013-02-28 |
Family
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US13/697,070 Abandoned US20130048245A1 (en) | 2010-05-20 | 2011-05-13 | Heat Exchanger Having Improved Drain System |
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US (1) | US20130048245A1 (en) |
WO (1) | WO2011146333A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170307208A1 (en) * | 2014-10-09 | 2017-10-26 | Nooter/Eriksen, Inc. | Once-through vertical tubed supercritical evaporator coil for an hrsg |
US20180135467A1 (en) * | 2016-11-14 | 2018-05-17 | General Electric Company | Cooling of gas turbine at varying loads |
US20220136776A1 (en) * | 2019-04-18 | 2022-05-05 | Guntner GMBH & co. KG | Heat exchanger assembly having at least one multi-pass heat exchanger and method for operating a heat exchanger assembly |
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US2286604A (en) * | 1938-06-25 | 1942-06-16 | Honeywell Regulator Co | Air conditioning system |
US20090173072A1 (en) * | 2008-01-07 | 2009-07-09 | Alstom Technology Ltd. | Flexible assembly of recuperator for combustion turbine exhaust |
US20090308580A1 (en) * | 2008-06-13 | 2009-12-17 | Hideaki Yumoto | Hot water generator |
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US5247991A (en) * | 1992-05-29 | 1993-09-28 | Foster Wheeler Energy Corporation | Heat exchanger unit for heat recovery steam generator |
JPH1163404A (en) * | 1997-08-25 | 1999-03-05 | Babcock Hitachi Kk | Waste heat recovery boiler and method of preventing corrosion of expansion joint of bottom plate of smoke duct of drain pipe piercing part |
JP2000028101A (en) * | 1998-07-10 | 2000-01-25 | Ishikawajima Harima Heavy Ind Co Ltd | Heating tube structure for exhaust heat recovery boiler |
JP3115294B2 (en) * | 1999-01-29 | 2000-12-04 | 株式会社東芝 | Exhaust heat recovery boiler and hot banking release method |
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2011
- 2011-05-13 WO PCT/US2011/036429 patent/WO2011146333A2/en active Application Filing
- 2011-05-13 US US13/697,070 patent/US20130048245A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US2286604A (en) * | 1938-06-25 | 1942-06-16 | Honeywell Regulator Co | Air conditioning system |
US20090173072A1 (en) * | 2008-01-07 | 2009-07-09 | Alstom Technology Ltd. | Flexible assembly of recuperator for combustion turbine exhaust |
US20090308580A1 (en) * | 2008-06-13 | 2009-12-17 | Hideaki Yumoto | Hot water generator |
Non-Patent Citations (1)
Title |
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Translation of Japanese Document JP 11063404A named TRANS-JP 11063404A * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170307208A1 (en) * | 2014-10-09 | 2017-10-26 | Nooter/Eriksen, Inc. | Once-through vertical tubed supercritical evaporator coil for an hrsg |
US10634339B2 (en) * | 2014-10-09 | 2020-04-28 | Nooter/Eriksen, Inc. | Once-through vertical tubed supercritical evaporator coil for an HRSG |
US20180135467A1 (en) * | 2016-11-14 | 2018-05-17 | General Electric Company | Cooling of gas turbine at varying loads |
US20220136776A1 (en) * | 2019-04-18 | 2022-05-05 | Guntner GMBH & co. KG | Heat exchanger assembly having at least one multi-pass heat exchanger and method for operating a heat exchanger assembly |
Also Published As
Publication number | Publication date |
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WO2011146333A2 (en) | 2011-11-24 |
WO2011146333A3 (en) | 2012-08-30 |
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