US20160025331A1 - Condensate preheater for waste heat steam generator - Google Patents

Condensate preheater for waste heat steam generator Download PDF

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Publication number
US20160025331A1
US20160025331A1 US14/774,840 US201414774840A US2016025331A1 US 20160025331 A1 US20160025331 A1 US 20160025331A1 US 201414774840 A US201414774840 A US 201414774840A US 2016025331 A1 US2016025331 A1 US 2016025331A1
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United States
Prior art keywords
condensate preheater
condensate
heat
heating surfaces
dew point
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US14/774,840
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English (en)
Inventor
Uwe Juretzek
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Siemens AG
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Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Assigned to SIEMENS AKTIENGESELLSCHAFT reassignment SIEMENS AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: JURETZEK, UWE
Publication of US20160025331A1 publication Critical patent/US20160025331A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
    • F02C6/18—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
    • F22D1/003—Feed-water heater systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
    • F22D1/02—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged in the boiler furnaces, fire tubes or flue ways
    • F22D1/08—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged in the boiler furnaces, fire tubes or flue ways the tubes having fins, ribs, gills, corrugations, or the like on their outer surfaces, e.g. in vertical arrangement

Definitions

  • the following relates to a condensate preheater for the waste heat steam generator of a gas and steam power station, and relates to preventing temperatures from falling below the exhaust gas dew points.
  • the fuels used in gas and steam power stations have amongst others variably high sulfur contents. Together with the water proportion which occurs from the combustion of gas or oil, there is a risk that if the temperatures fall below the corresponding exhaust gas dew points, sulfuric acid, sulfurous acids and water will be deposited in the so-called cold part of the waste heat steam generator (in particular in the condensate preheater), and lead to corrosion and finally to component failure.
  • the condensate temperature must be raised to a corresponding minimum temperature before the condensate enters the condensate preheater of the waste heat steam generator. This is because the heat transmission is determined from the water side, i.e. the pipe wall temperature on the exhaust gas side corresponds approximately to the condensate temperature on the inside.
  • the condensate temperature is in turn set by the defined cooling conditions (cooling type, design of cooling system, ambient conditions etc.).
  • Another possibility is to heat the condensate by an external steam or water-heated preheater before it enters the waste heat boiler.
  • an external hot water or steam source can supply the necessary heat, or the steam heating of the preheater using steam extracted from the steam turbine or hot steam generation takes place in the waste heat steam generator at a temperature level lying above the dew point.
  • An aspect relates to a condensate preheater of the type cited initially in which, during operation, the temperature at the condensate preheater heating surfaces does not fall below an exhaust gas dew point.
  • a further aspect relates to a condensate preheater of this type for a waste heat steam generator comprising condensate preheater heating surfaces around which exhaust gas from a gas turbine flows in operation in order to heat the water flowing in the condensate preheater heating surfaces, a heat transfer coefficient of the condensate preheater heating surfaces is selected such that in operation, a surface temperature of the condensate preheater heating surfaces lies above an exhaust gas dew point.
  • the condensate preheater has a condensate preheater inlet and a condensate preheater outlet, and the heat transfer coefficient at the condensate preheater inlet is reduced relative to the heat transfer coefficient at the condensate preheater outlet.
  • embodiments of the invention is now based on the concept of reducing the heat transmission accordingly, at the individual heat exchanger pipes of the condensate preheater which could be affected if the temperature falls below an exhaust gas dew point due to too low a condensate temperature, so far that the wall temperature of the heat exchanger pipe on the exhaust side rises above the exhaust gas dew point.
  • the reduction in heat transmission is thus applied to condensate preheater heating surfaces which can only reach the minimum permitted pipe outer wall temperature in this way. As soon as the condensate temperature safely reaches the exhaust gas dew point temperature (even under changing operating conditions), this measure may be omitted.
  • the heat transfer coefficient at the condensate preheater inlet is reduced compared with the heat transfer coefficient at the condensate preheater outlet, it can be ensured that only where the temperature would otherwise fall below the dew point is a reduction in the heat transmission achieved, and at the other points the normally desirable maximum heat transmission persists in the interests of keeping the total heating surface of the waste heat steam generator as small as possible.
  • this measure concerns the water vapor dew point which is relevant even in practically sulfur-free fuel gases, and lies in the temperature range of around 50 to 65° C. This depends on the quantity of hydrogen in the fuel gas and increases as the fuel gas and combustion air humidity rises. If the temperature falls below the dew point, the presence of carbon dioxide may lead to corrosion at the heating surfaces at the water vapor dew point.
  • the exhaust gas dew point below which the temperature does not fall is a sulfuric acid dew point.
  • the dew point of diluted sulfuric acid which is higher than the water vapor dew point, lies in the temperature range between 90 and 160° C. and rises with the sulfur content of the fuel.
  • a heat-insulating layer is applied to at least one condensate-carrying part of the condensate preheater heating surfaces lying closest to the condensate preheater inlet.
  • At least one condensate preheater heating surface lying closest to the condensate preheater inlet is a pipe-in-pipe construction, for example made of C-steel, in which a heat-insulating layer is arranged in an inter-pipe space.
  • the heat-insulating layer it is suitable, because it is simple and economic, for the heat-insulating layer to comprise sand, in particular dry sand.
  • the outer pressureless pipe is here designed (as before) with corresponding ribs to enlarge the surface area, the heat-insulating layer and where applicable the diameter of the outer pipe are optimized according to the outer wall temperature of the inner pipe which has already been reached.
  • the inner pipe is designed as before, according to permitted pressure losses, design pressure etc.
  • embodiments of the invention allow the nominal boiler heater surface in the condensate preheater to be reduced by more than 25% in comparison with a solution of a condensate recirculation, since the reduced condensate mass flow in the condensate preheater over-compensates for the influence of the lower heat transfer coefficient.
  • the amount of tubular steel used would increase slightly on use of the abovementioned exemplary pipe-in-pipe construction, however the outer envelope of the waste heat steam generator would be slightly smaller and no collector would be required. Thus approximately the same investment can be assumed.
  • the benefits in each case of a reduced surface are requirement of the waste heat steam generator and a reduced pump power for the condensate pump (due to lower pressure losses) with a corresponding reduction in the associated energy consumption.
  • the system availability would increase since active components such as pumps and valves are replaced by a passive heat-insulating layer.
  • the rise in condensate inlet temperature may be omitted as long as it can be guaranteed that the temperature as a whole does not fall below the dew point temperature of the exhaust gas (i.e. the heat quantity available in the exhaust gas is sufficient for condensate preheating as a whole).
  • the proposed solution is significantly cheaper due to the lower material and production costs.
  • FIG. 1 depicts a view of a known condensate preheater with feed water extraction
  • FIG. 2 depicts a partial view of a further known condensate preheater with additional condensate recirculation pump
  • FIG. 3 depicts a view of an embodiment of a condensate preheater according to the invention.
  • FIG. 4 depicts a pipe-in-pipe construction for an embodiment of the condensate preheater according to the invention.
  • FIG. 1 shows diagrammatically and as an example a view of a known condensate preheater 12 in the so-called cold part 13 of the waste heat steam generator 2 with feed water extraction.
  • Condensate is supplied via the condensate line 14 to the condensate preheater 12 , where it is heated by heat exchange with the exhaust gas 4 flowing through the waste heat steam generator 2 .
  • the condensate line 14 branches into lines 15 and 16 .
  • Line 15 conducts the condensate to the low pressure drum 17 .
  • the condensate diverted into the line 16 is supplied via a feed water pump 18 to the medium- 19 and high-pressure drums 20 .
  • FIG. 1 furthermore shows a cold bypass of the condensate preheater via a secondary line 21 and a line 22 for a minimum backflow of the feed water to the condensate line 14 , because the feed water pump 18 is in permanent operation and, even if the medium- 19 and high-pressure drums 20 are not to be supplied with feed water, a low through-flow of feed water must be guaranteed by the feed water pump 18 .
  • hot water may be returned from the condensate preheater outlet 6 to the condensate preheater inlet 5 .
  • a recirculation pump 24 is required.
  • FIG. 3 shows a diagrammatic view of an embodiment of the condensate preheater 1 according to the present invention.
  • the feed water return and condensate recirculation as shown in FIGS. 1 and 2 may be omitted. Instead, the heat transfer coefficient of the condensate preheater heating surfaces 3 is selected such that in operation, a surface temperature of the condensate preheater heating surfaces 3 lies above an exhaust gas dew point, i.e. above the water vapor dew point or even above the sulfuric acid dew point.
  • FIG. 4 shows a pipe-in-pipe construction 8 according to the invention, as may be used in at least one condensate preheater heating surface 3 lying closest to the condensate preheater inlet 5 .
  • the heat-insulating layer 9 e.g. dry sand 11
  • the outer pressureless pipe 25 is, as before, designed with corresponding ribs 26 to enlarge its surface area, the heat-insulating layer 9 and where applicable the diameter of the outer pipe 25 are each optimized according to the outer wall temperature of the inner pipe 27 which has already been reached.
  • the inner pipe 27 is designed as before according to the permitted pressure losses, design pressure etc.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)
  • Air Supply (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
US14/774,840 2013-03-13 2014-02-18 Condensate preheater for waste heat steam generator Abandoned US20160025331A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102013204396.1 2013-03-13
DE102013204396.1A DE102013204396A1 (de) 2013-03-13 2013-03-13 Kondensatvorwärmer für einen Abhitzedampferzeuger
PCT/EP2014/053078 WO2014139765A2 (de) 2013-03-13 2014-02-18 Kondensatvorwärmer für einen abhitzedampferzeuger

Publications (1)

Publication Number Publication Date
US20160025331A1 true US20160025331A1 (en) 2016-01-28

Family

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Application Number Title Priority Date Filing Date
US14/774,840 Abandoned US20160025331A1 (en) 2013-03-13 2014-02-18 Condensate preheater for waste heat steam generator

Country Status (5)

Country Link
US (1) US20160025331A1 (de)
EP (1) EP2959120B1 (de)
KR (1) KR101662474B1 (de)
DE (1) DE102013204396A1 (de)
WO (1) WO2014139765A2 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10495393B2 (en) 2016-03-10 2019-12-03 General Electric Technology Gmbh System and method for improving the performance of a heat recovery steam generator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019522140A (ja) 2016-05-23 2019-08-08 シーメンス エナジー インコーポレイテッド ベンチュリ効果を利用した凝縮液再循環ポンプを備えたコンバインドサイクルパワープラント

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203404A (en) * 1961-02-17 1965-08-31 Avy L Miller Water heater with heat insulating coating on tubes
GB1228006A (de) * 1968-05-30 1971-04-15
US20040187688A1 (en) * 2001-09-14 2004-09-30 Erhard Liebig Process and apparatus for the thermal degassing of the working medium of a two-phase process
US20140260286A1 (en) * 2013-03-14 2014-09-18 Zaher El Zahab Localized flue gas dilution in heat recovery steam generator
US20150192367A1 (en) * 2012-08-01 2015-07-09 Heliofocus, Ltd. Auxiliary conduit assembly

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Publication number Priority date Publication date Assignee Title
FR976227A (fr) * 1948-10-05 1951-03-15 Perfectionnement à l'alimentation en eau des économiseurs
DE1085890B (de) * 1954-08-09 1960-07-28 Mont Kessel Herpen & Co Komm G Aus Rohrtafeln bestehende Beruehrungsheizflaeche fuer Abhitze-Wasserrohrkessel
US4173949A (en) * 1978-01-23 1979-11-13 Tranter, Inc. Feedwater preheat corrosion control system
IN161926B (de) * 1984-10-29 1988-02-27 Kraftwerk Union Ag
US4799461A (en) * 1987-03-05 1989-01-24 Babcock Hitachi Kabushiki Kaisha Waste heat recovery boiler
DE19736889C1 (de) * 1997-08-25 1999-02-11 Siemens Ag Verfahren zum Betreiben einer Gas- und Dampfturbinenanlage und Gas- und Dampfturbinenanlage zur Durchführung des Verfahrens
KR20000067162A (ko) * 1999-04-24 2000-11-15 황해웅 인산염 망간계 피막의 마모윤활 특성 개선방법 및 이에 따라 제조된 마모윤활 특성이 우수한 인산염 망간계 피막
US6508206B1 (en) * 2002-01-17 2003-01-21 Nooter/Eriksen, Inc. Feed water heater
US7043912B1 (en) * 2004-12-27 2006-05-16 Utc Power, Llc Apparatus for extracting exhaust heat from waste heat sources while preventing backflow and corrosion
EP1801363A1 (de) * 2005-12-20 2007-06-27 Siemens Aktiengesellschaft Kraftwerksanlage

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203404A (en) * 1961-02-17 1965-08-31 Avy L Miller Water heater with heat insulating coating on tubes
GB1228006A (de) * 1968-05-30 1971-04-15
US20040187688A1 (en) * 2001-09-14 2004-09-30 Erhard Liebig Process and apparatus for the thermal degassing of the working medium of a two-phase process
US20150192367A1 (en) * 2012-08-01 2015-07-09 Heliofocus, Ltd. Auxiliary conduit assembly
US20140260286A1 (en) * 2013-03-14 2014-09-18 Zaher El Zahab Localized flue gas dilution in heat recovery steam generator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10495393B2 (en) 2016-03-10 2019-12-03 General Electric Technology Gmbh System and method for improving the performance of a heat recovery steam generator

Also Published As

Publication number Publication date
WO2014139765A2 (de) 2014-09-18
EP2959120A2 (de) 2015-12-30
EP2959120B1 (de) 2017-06-14
WO2014139765A3 (de) 2015-04-16
KR20150119075A (ko) 2015-10-23
DE102013204396A1 (de) 2014-09-18
KR101662474B1 (ko) 2016-10-04

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Owner name: SIEMENS AKTIENGESELLSCHAFT, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JURETZEK, UWE;REEL/FRAME:036540/0306

Effective date: 20150831

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION