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CA2046617A1 - Method of controlling a pfbc power plant and a pfbc power plant with equipment for such control - Google Patents

Method of controlling a pfbc power plant and a pfbc power plant with equipment for such control

Info

Publication number
CA2046617A1
CA2046617A1 CA002046617A CA2046617A CA2046617A1 CA 2046617 A1 CA2046617 A1 CA 2046617A1 CA 002046617 A CA002046617 A CA 002046617A CA 2046617 A CA2046617 A CA 2046617A CA 2046617 A1 CA2046617 A1 CA 2046617A1
Authority
CA
Canada
Prior art keywords
steam
combustor
gas turbine
pressure
bed
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
CA002046617A
Other languages
French (fr)
Inventor
Leif Kemmer
Krishna Pillai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Stal AB
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of CA2046617A1 publication Critical patent/CA2046617A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01KSTEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02Plants 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
    • F01K23/06Plants 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
    • F01K23/061Plants 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 combustion in a fluidised bed
    • F01K23/062Plants 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 combustion in a fluidised bed the combustion bed being pressurised
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01KSTEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K21/00Steam engine plants not otherwise provided for
    • F01K21/04Steam engine plants not otherwise provided for using mixtures of steam and gas; Plants generating or heating steam by bringing water or steam into direct contact with hot gas
    • F01K21/047Steam engine plants not otherwise provided for using mixtures of steam and gas; Plants generating or heating steam by bringing water or steam into direct contact with hot gas having at least one combustion gas turbine
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02CGAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C3/00Gas-turbine plants characterised by the use of combustion products as the working fluid
    • F02C3/20Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
    • F02C3/205Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products in a fluidised-bed combustor

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)

Abstract

ABSTRACT

The invention relates to a method of increasing the total efficiency of a PFBC power plant with a gas turbine cycle and a steam turbine cycle. Low grade heat is utilized for generation of steam which is injected into the combustor (10) and increases the mass flow through the gas turbine (30) and hence the gas turbine power generated. Preferably, waste gases from the gas turbine (30) of the plant are utilized for generation of steam in a steam generator (84) separate from the main steam cycle (38,40). The invention also relates to a PFBC power plant, in which low grade steam is injected into the combustor (10).

Description

L66~
A met~h~L~l~ increasina the effi~iency of a PFBC power plan~

TECHNICAL FIELD

The present invention relates to a method of increasing the total efficiency of a PFBC power plant with a gas turbine cycle and a steam turbine cycle by the injection of steam into the combustor of the plant. Further, the invention relates to a PFBC power plant for application of the above-mentioned method.

SUMMARY OF THE INVENTION

According to the invention, the total efficiency is increased by utilizing low grade heat in a PFBC power plant for generation of steam which is injected into the bed vesseL and increases the mass flow through the gas turbine cycle and hence the gas turbine power. Conventionally, waste gases from the gas turbine are utilized for generation of this steam, but also other low grade heat within the power plant can be utilized. The steam is generated in a steam generator or waste heat boiler separate from the steam turbine cycle. This boiler is supplied with waste gases with such a temperature that the steam which is generated attains a pressure which exceeds the working pressure in the combustor so that it can be injected directly into the combustor. The steam pressure ist however, considerably lower than the steam pressure in the steam cycle.

It is also possible to utilize steam extraction flows from the steam turbine. This steam is taken at a pressure which somewhat exceeds the working pressure in the combustor and is injected into the combustor.

The object of the invention is primarily to utilize the heat contents of waste gases from a gas turbine in a more efficient way than before. Instead of utilizing the entire heat quantity in the waste gases from the gas turbine in the : : . :: .
: .
2 ~ ~ ~6~7 steam cycle only for feedwater preheating, intermediate superheating of steam, etc., only part of the heat quantity is used for increasing the power in the steam turbine cycle.
In a plant with an operating pressure of about 16 bar in the combustor, the waste gases are first utilized in a high temperature heat exchanger, for example for preheating of feedwater, and then in a steam boiler for generation of the steam which is injected into -the combustion bed such that the increased mass flow throu~h the gas turbine increases the power generated in the gas turbine cycle.
':
The temperature of the low grade source of heat must be so high that steam with a pressure suitable for injection, about 20 bar, is obtained. The injected steam takes up energy from the bed. In case of unchanged thermal firing rate in the power plant, the steam in~ection results in the steam qeneration in the bed tubes, and hence the stea~ flow -in the steam turbine cycle, being reduced. In total terms, an increase of efficiency and of electric power in the plant -is obtained by ensuring that the power increase in the gas --turbine cycle is greater than the power reduction in the steam cycle.
.: - ~
An embodiment of the invention will be described in the following with reference to the accompanying figure.

In the figure, 10 designates a combustor with combustion of t`
a ~uel, say coal, in a fluidized bed 12. The combustor 10 and a cleaning plant for separation of dust in the combustion gases, symbolized by a cyclone 14, are contained within a pressure vessel 16 and surrounded by compressed combustion air in the space 18 between the pressure vessel 16 and the combustor 10 and the cyclone 14. Fuel is supplied to the bed 12 of the combustor 10 through the inlet conduit 20. For fluidization of the bed 12 and combustion ~ .
of supplied fuel, the combustor 10 is supplied with air from the space 18 via an air distributing bottom 22 with nozzles 24. The combustion gases are collected in the freeboard 26 ',.

6~
and are passed, after cleaning in the cyclone 14, through the conduit 28 to a gas turbine 30. This drives a compressor 32 which feeds the space 18 in the pressure vessel 1 with compressed combustion air and a generator 34.
The gas turbine may be of single-shaft design as in the figure, or or two-shaft design in which case one shaft drives the compressor 32 and the other shaft drives the gene~ator 34. The compressor 32 is provided with an intermediate cooler 36. Heat from this cooler can be utilized for preheating feedwater.

The combustor 10 accomodates nests of boiler tubes 38 and 40 for cooling of the bed and for generation and superheating of steam and intermediate superheating of steam, respectively. Steam generated and superheated in the tubes 38 is passed in a conduit 92 to the high pressure turbine 94, from there in the cc-nduit 46 to the intermediate superheater 40 and from there in the conduit 48 to the low pressure turbine S0. The turbines 94 and 50 drive the generator 52. Steam for feedwater preheating can be taken out from the turbine 44, 50 through the steam extraction conduit 5~. The low pressure turb ine 50 is connected to the condenser 56 through the conduit 58. Condensate is collected in the condensate tank 60. The feedwater pump 62 pumps the condensate through the feedwater preheaters 64, 66 and 68 and the conduit r70 to the steam tubes 38 in the combustor 10. Heat from the intermediate cooler 36 of the compressor and heat from the steam extracted from the turbine 44, 50 can be utilized for the preheatlng in the feedwater preheaters 69 and 66. The waste gases from the gas ~urbine 30 are passed to the feedwater preheater 68 via the conduit 71 and from there to the steam boiler 72, the feedwater preheater 79 for heating feed water to the steam boiler 72, the gas filter 76~ the economizer 78 and from there to the chimney 80. In the embodiment shown, also an ash cooler 82 is utilized as preheater for the feedwater of the steam boiler 72. Water from the steam drum 84 of the boiler 72 is circulated through the tubes 86 by means of a ., . , " ,, , , . , ,~
, :, ::

" ,, ', . ,. "' ~ ' ; ' ' '. ' " ' ' ', ' .'``' ;,'. ' " ,': ' ,- 4 Z~46~
` circulation pump 88. The steam drum is connected to the steam injection nozzles in the combustor by means of the ~ :
steam conduit 90. Dilution water to the plant is supplied via the conduit 92. The economizer 78 is connected, by a conduit 94, to the feedwater conduit 96 downstream of the feedwater pump 62 and is utilized for feeding the tubes 38 in the combustor 10 as well as for feeding the steam boiler 72. The feedwater flow to the steam boiler 70 is controlled by a valve 98 in the conduit lQ0 between the economizer 78 and the ash cooler!feedwater preheater 82.

In a PFBC power plant, which at full power operates with a `
pressure of about 16 bar, the high temperature economizer/the feedwater preheater 68 is dimensioned such that the waste gases from the steam turbine which leave the feedwater preheater 68 have such a temperature that steam wi.th a pressure exceeding 16 bar can be generated. In the ~ `
steam boiler 72 a suitable quantity of steam with a pressure - :
of about 20 bar can be generated. In a plant with a power o~ 800 MWt, the suitable quantity is about 25 kg/s. The s~eam is injected into the combustor and increases the mass flow through the turbine and hence the gas turbine power generation. The heating of the steam injected into the "
combustor results in reduced steam generation in the steam cycle and reduced power. The power gain in the gas turbine :;
cycle is at least twice as great as the power loss in the steam turbine cycle. The net power gain may amount to 10-15 -MWe in an ~00 MWt plant. This corresponds to an increase of the total efficiency of the plant of about 1-2~. A total net eEficiency of approximately 46% is obtainable.

The power gain is achieved without any increase in the cost of installation. The cost increase for the gas turbine cycle is insignificant and is compensated for b~ reduced costs in the steam turbine cycle. This results in smaller and hence less expensive steam turbines and condenser~ The increased consumption of feedwater for generation of steam in the waste heat boiler 72 for bed injection entails a ,,, . . . . : ' :. : ' : ' : , j, ~6~7 , . s certain increased operating cost for preparatlon of the feedwater.

:

' :

~ ~ , ' . .

~':

!; . ;, '. ! . ' ,' ., .

Claims (3)

1. A method of increasing the total efficiency of a power plant with combustion of a fuel, primarily coal, in a fluidized bed of particulate material, at a pressure exceeding atmospheric pressure, a so-called PFBC power plant comprising a combustor (10) with a bottom (22) with nozzles (24) for supplying the combustor with air for fluidization of a bed (12) and combustion of fuel supplied to the bed (12), a gas turbine (30) driven by combustion gases from the combustor (10), a compressor (32) which is driven by the gas turbine (30) and which compresses fluidization and combustion air, a generator (34) driven by the gas turbine (30), tubes (30,40) arranged in the combustor (10) for cooling the bed and generating steam for a steam turbine (44, 50) which drives a generator (52), c h a r a c t e r i z e d in that the mass flow through the gas turbine (30) and hence the gas turbine power generation are increased by steam being injected into the combustor (10) and steam with the necessary pressure for injection into the combustor (10) being either generated by low grade heat in a separate steam generator (72,89) or being discharged from a steam turbine (50) which is driven by the steam generated in the combustor (10).
2. A method according to claim 1, c h a r a c t e r i -z e d in that the waste gases from the gas turbine (30) are utilized as a heating agent in a low pressure steam generator (72,84) for generation of steam with a pressure exceeding the operating pressure in the combustor (10) and that the generated steam is injected into the combustor (10) and increases the mass flow through the gas turbine (30) and hence the gas turbine power.
3. A power plant with combustion of a fuel, primarily coal, in a fluidized bed of particulate material, at a pressure exceeding the atmospheric pressure, a so-called PFBC power plant comprising a combustor (10) with a bottom (22) with nozzles (24) for supplying the combustor (10) with air for fluidization of a bed (12) and combustion of fuel supplied to the bed (12), a gas turbine (30) which is driven by combustion gases from the combustor (10), a compressor (32) which is driven by the gas turbine (30) and which compresses the fluidization and combustion air, a generator (32) driven by the gas turbine (30), tubes arranged in the combustor for cooling the bed and generating steam for a steam turbine (44,50) which drives a generator (52), c h a r a c t e r i z e d in that nozzles for injection of steam into the combustor (10) are either connected to a low pressure steam generator (72,84) which is heated by waste gases from the gas turbine (30), or to an outlet (54) for discharging steam in the steam turbine (50) at a point where the pressure of the steam somewhat exceeds the pressure of the combustor (10).
CA002046617A 1989-02-03 1990-02-01 Method of controlling a pfbc power plant and a pfbc power plant with equipment for such control Abandoned CA2046617A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8900384A SE463220B (en) 1989-02-03 1989-02-03 SET TO INCREASE THE EFFECTIVENESS OF A PFBC POWER PLANT AND POWER PLANT
SE8900384-2 1989-02-03

Publications (1)

Publication Number Publication Date
CA2046617A1 true CA2046617A1 (en) 1990-08-04

Family

ID=20374945

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002046617A Abandoned CA2046617A1 (en) 1989-02-03 1990-02-01 Method of controlling a pfbc power plant and a pfbc power plant with equipment for such control

Country Status (6)

Country Link
EP (1) EP0456702A1 (en)
JP (1) JPH04503235A (en)
CA (1) CA2046617A1 (en)
FI (1) FI913694A0 (en)
SE (1) SE463220B (en)
WO (1) WO1990008887A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2624891B2 (en) * 1990-11-30 1997-06-25 株式会社日立製作所 Pressurized fluidized bed boiler power plant
US5375409A (en) * 1993-10-08 1994-12-27 Ahlstrom Pyropower, Inc. Pressurized fluidized bed combined gas turbine and steam turbine power plant with steam injection
DE19902437C5 (en) * 1999-01-22 2017-01-12 General Electric Technology Gmbh Method and device for rapid startup and for rapid increase in output of a gas turbine plant

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4436057A (en) * 1979-06-15 1984-03-13 Energy Equipment Co. Ltd. Method and apparatus enabling thermal energy recovery in combustor operation
SE434883B (en) * 1980-10-15 1984-08-20 Stal Laval Turbin Ab SET TO OPERATE A COMBINED GAS ANTURBIN INSTALLATION AND COMBINED GAS ANTURBIN INSTALLATION FOR USE OF THE SET
US4424766A (en) * 1982-09-09 1984-01-10 Boyle Bede Alfred Hydro/pressurized fluidized bed combustor
US4488512A (en) * 1982-11-04 1984-12-18 Boyle Bede Alfred Feedstock injection system for fluidized bed combustor
DE3518512A1 (en) * 1985-05-23 1986-11-27 Inter Power Technologie GmbH, 6600 Saarbrücken METHOD FOR GENERATING ELECTRICITY AND HEAT BY MEANS OF A PRINTED FLUID BED BURNER

Also Published As

Publication number Publication date
FI913694A7 (en) 1991-08-02
JPH04503235A (en) 1992-06-11
SE8900384D0 (en) 1989-02-03
FI913694A0 (en) 1991-08-02
SE463220B (en) 1990-10-22
WO1990008887A1 (en) 1990-08-09
EP0456702A1 (en) 1991-11-21
SE8900384L (en) 1990-08-04

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Legal Events

Date Code Title Description
FZDE Discontinued