Method of power generation and load management with hybrid mode of operation of a combustion turbine derivative power plant

• US 5,778,675 A
• Filed: 06/20/1997
• Issued: 07/14/1998
• Est. Priority Date: 06/20/1997
• Status: Expired due to Term

• Current Assignee: Electric Power Research Institute Incorporated, Energy Storage and Power LLC
• Original Assignee: Electric Power Research Institute Incorporated
• Inventors: Nakhamkin, Michael
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Ciric, Ljiljana V.
• Application Number:
  US08/879,792
• Time in Patent Office: 389 Days
• Field of Search: 60/652, 60/659, 60/650, 60/682, 60/39.17, 60/727, 60/39.04, 60/39.05, 60/39.182, 60/39.183, 60/728, 60/661, 60/662, 60/663, 60/667, 60/681
• US Class Current: 60/652
• CPC Class Codes: F02C 6/16 for storing compressed air
• CPC Class Codes: F02C 7/143 before or between the compressor stages
• CPC Class Codes: F05D 2260/211 by intercooling, e.g. during a compression cycle
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

The invention provides a stand-alone, hybrid combustion turbine derivative power generation system sized for the most efficient and cost-effective base load operation that is also capable of providing, using air storage techniques, short-duration peak power, which is approximately 200% of the base load rating, and short-duration intermediate load power over a whole a range of loads between a base load and a peak load. The peak/intermediate power is also delivered with the best practical efficiency possible. The hybrid system may employ a variety of combustion turbine thermal cycles, including a simple cycle combustion turbine plant, combustion turbine plants with intercooling, reheat, recuperation, steam injection and humidification, and combined cycle power plants.

Claims

1. A method of providing a hybrid combustion turbine derivative power generation system including

modifying a combustion turbine derivative power generation system sized for base load operation and having at least one power shaft assembly having at least one compressor, at least one expansion turbine and a generator;

and a combustor feeding said turbine, said modification including (1) separating said compressor and said turbine, (2) replacing said generator with a double-ended motor/generator selected to meet peaking requirements, of said hybrid combustion turbine derivative power generation system and (3) placing said motor/generator between said compressor and said turbine, said motor generator having a turbine driving clutch structure on one end thereof and a compressor driving clutch structure on the other end thereof, said compressor driving clutch structure being operatively associated with said compressor so that said compressor is driven by said motor/generator when said compressor driving clutch structure is engaged and said turbine driving clutch structure being operatively associated with said turbine so that said motor/generator may be driven by said turbine when said turbine driven clutch structure is engaged,

providing an additional compression and compressed air storage system comprising;

a boost compressor,

an intercooler feeding the boost compressor,

an electric motor for driving the boost compressor,

an aftercooler downstream of said boost compressor,

a compressed air storage downstream of said aftercooler,

integrating said modified combustion turbine derivative power generation system and said additional system to provide various flow paths through said hybrid system with

a flow path structure permitting communication between an outlet of said compressor and an inlet to said intercooler feeding said boost compressor,

a connection structure permitting communication between an outlet of said air storage and an inlet to the combustor,

a bypass structure having a first end coupled to said flow path structure and a second end coupled to said connection structure, said bypass structure permitting communication between an output of said compressor of said at least one power shaft assembly and an inlet of said combustor, and

valving to selectively control flow through said flow path structure, said connection structure and said bypass structure,

the integration ensuring the provision of (i) a base load powers (ii) a peak load power which is greater than said base load power to meet peaking requirements, by using air from said air storage, (iii) an intermediate range of power loads between said base load power and said peak load power, by using air from said air storage or a combination of air from said air storage and said compressor, and (iv) a charging mode of operation wherein said air storage is charged with compressed air.

2. The method according to claim 1, wherein said valving includes a first valve system for controlling air flow in said flow path structure and disposed between said compressor and said intercooler feeding the boost compressor of said at least one power shaft assembly, a second valve system for controlling air flow in said connection structure and disposed between said air storage and said combustor, and a third valve system for controlling air flow in said bypass structure.

3. The method according to claim 2, further including a recuperator, downstream of a coupling location of said second end of said bypass structure and said connection structure and feeding said combustor.

4. The method according to claim 3, ensuring a base load power is provided when said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said motor/generator drives said at least one compressor of said at least one power shaft assembly, said first and second valve systems are closed and said third valve system is open so as to define an air and gas flow path permitting air and gas to flow through said at least one compressor, through said bypass structure through the recuperator and to the combustor feeding said at least one turbine, and gas moves to the at least one turbine such that the difference between power generated by said at least one turbine and power consumed by said at least one compressor will be converted to electric power by said motor/generator and delivered to customers.

5. The method according to claim 3, ensuring a peak or intermediate load power is provided when said turbine driving clutch structure of said at least one power shaft assembly is engaged and said compressor driving clutch structure of said at least one power shaft assembly is disengaged such that said at least one turbine drives said motor/generator, said first and third valve systems are closed and said second valve system is open so as to define an air and gas flow path where compressed air stored in said air storage moves through said recuperator and to the combustor and gas moves to said at least one turbine of the at least one power shaft assembly such that substantially all power generated by said at least one turbine goes for electric power generation.

6. The method according to claim 3, wherein said charging mode includes a self-charging mode of operation when said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said at least one compressor is driven by said motor/generator, said second valve system is closed and said first and third valve systems are open so as to define an air and gas flow path where compressed air from said at least one compressor is divided such that a portion of the air passes through the bypass structure through said recuperator to the combustor and gas moves to the at least one turbine of the at least one power shaft assembly and another portion of the air moves along said flow path structure and through said intercooler and is further compressed in said boost compressor and cooled in the aftercooler, the air compressed in the boost compressor is then charged into the air storage.

7. The method according to claim 3, wherein said charging mode is provided when said turbine driving clutch structure of said at least one power shaft assembly is disengaged and said compressor driving clutch structure of said at least one power shaft assembly is engaged such that said at least one compressor is driven by said motor/generator, said second and third valve systems are closed and said first valve system is open so as to define an air flow path where compressed air from said at least one compressor moves along said flow path structure and through said intercooler and is then further compressed in said boost compressor and cooled in the aftercooler, the compressed air thereafter is charged into the air storage, said motor/generator and said electric motor being coupled to and powered by an electric grid.

8. The method according to claim 3, ensuring an alternative intermediate load mode of operation is provided when air flow to said compressor of said at least one power shaft assembly is reduced and said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said at least one compressor, operating at part load, is driven by said motor/generator, said first valve system is closed and said second and third valve systems are open so as to define an air and gas flow path where compressed air from said at least one compressor passes through the bypass structure and is combined with compressed air from said air storage at said coupling location, said combined air moves through said recuperator and to said combustor and then gas moves to the at least one turbine of said at least one power shaft assembly to produce a specified amount of intermediate power.

9. The method according to claim 1, further providing intercooling to reduce power consumption by a compressor of said at least one power shaft assembly.

10. The method according to claim 1, wherein said air storage is selected from the group consisting of:

high pressure piping, at least one pressure vessel, concrete reinforced structures, and an underground geological formation.

11. The method according to claim 6, wherein the compressed air storage self-charging mode of operation includes controlling said first valve system and said third valve system to provide minimum air flow to the recuperator and then to the combustor, the combustor feeding gas to the at least one turbine to ensure that the at least one turbine has enough capacity to mechanically drive said at least one compressor and to electrically drive the boost compressor, and remaining air flow is directed for charging the air storage.

12. The method according to claim 3, further providing a water heater connected along a turbine exhaust flow path to an outlet of said recuperator to preheat water, and including a saturator being fed with hot water and disposed in a flow path generally at a location downstream of said coupling location where compressed air from a highest pressure compressor of said at least one power shaft assembly and compressed air from the air storage combines, such that compressed air from the highest pressure compressor, from the air storage, or from both the air storage and the highest pressure compressor, passes through said saturator and humidified, and air preheated by hot water, is sent to said recuperator.

13. The method according to claim 1, further providing a heat recovery steam generator to receive an exhaust of the lowest pressure turbine to recover exhaust gas heat for generating steam.

14. The method according to claim 1, further providing a steam turbine bottoming cycle with a heat recovery steam generator, said heat recovery steam generator being connected to said hybrid system to receive an exhaust gas of a lowest pressure turbine so as to recover an exhaust gas heat for generation of steam, steam being expanded through at least one steam turbine, condensed in at least one condenser, deaerated in a deaerator and returned back to said heat recovery steam generator.

15. A method of operating a hybrid combustion turbine derivative power generation system, said hybrid system including (1) a modified combustion turbine derivative power generation system sized for base load operation and having at least one power shaft assembly having at least one compressor, at least one expansion turbine, and a double-ended motor/generator between said compressor and said turbine, said motor/generator being selected to meet peak load requirements of said hybrid combustion turbine derivative power generation system and having a turbine driving clutch structure on one end thereof and a compressor driving clutch structure on the other end thereof, said compressor driving clutch structure being operatively associated with said compressor so that said compressor is driven by said motor/generator when said compressor driving clutch structure is engaged and said turbine driving clutch structure being operatively associated with said turbine so that said motor/generator may be driven by said turbine when said turbine driving clutch structure is engaged, and a combustor feeding said expansion turbine, and (2) an additional system selected to support peak and intermediate load requirements, said additional system having a boost compressor and an intercooler feeding cooled air to said boost compressor with an outlet of the compressor of the power shaft assembly being connected to an inlet of said intercooler via a flow path structure, an electric motor for driving said boost compressor, an aftercooler downstream of said boost compressor, a compressed air storage downstream of said aftercooler, a connection structure permitting communication between an outlet of said air storage and an inlet to the combustor, a first valve system for controlling air flow in said flow path structure and disposed between said compressor and said intercooler feeding the boost compressor, a second valve system for controlling air flow in said connection structure and disposed between said air storage and said combustor, a bypass structure having a first end coupled to said flow path structure and a second end coupled to said connection structure, said bypass structure permitting communication between an output of said compressor of said at least one power shaft assembly and an inlet of said combustor, and a third valve system for controlling air flow in said bypass structure, said hybrid system integrating said modified combustion turbine derivative power generation system and said additional system to provide base load power, and peak and intermediate load power, the method including:

controlling said valve systems to permit alternative flow path arrangements and controlling said clutch structures to

(i) provide base load power, wherein said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said motor/generator drives said at least one compressor of said at least one power shaft assembly, said first and second valve systems being closed and said third valve systems being open so as to define an air and gas flow path through the compressor, through said bypass structure through the combustor feeding said turbine, and to the turbine, and

(ii) provide power increased from the base load for peak or intermediate load requirements, wherein said turbine driving clutch structure of said at least one power shaft assembly is engaged and said compressor driving clutch structure of said at least one power shaft assembly is disengaged such that said at least one turbine drives said motor/generator, said first and third valve systems being closed and said second valve system being open so as to define an air and gas flow path where compressed air stored in said air storage moves through said combustor to said at least one turbine of the at least one power shaft assembly.

16. The method according to claim 15, further including a recuperator, downstream of a coupling location of said second end of said bypass structure and said connection structure and feeding said combustor.

17. The method according to claim 16, wherein:

to provide said base load power, said air and gas flow path is such that compressed air moves through the at least one compressor, through said bypass structure, through the recuperator and the combustor feeding said at least one turbine, and to the at least one turbine, and to provide said increased peak or intermediate power, said air and gas flow path is such that compressed air stored in said air storage moves through said recuperator to the combustor and to said at least one turbine of the at least one power shaft assembly.

18. The method according to claim 16, further including controlling said valve systems to permit alternative flow path arrangements and controlling said clutch structures to enable:

a compressed air storage self-charging mode of operation, wherein said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said at least one compressor is driven by said motor/generator, said second valve system being closed and said first and third valve systems being open so as to define an air and gas flow path where compressed air from said at least one compressor is divided such that a portion of the air passes through the bypass structure through the recuperator and combustor feeding the at least one turbine, and gas moves to the at least one turbine of the at least one power shaft assembly and another portion of the air moves along said flow path structure and through said intercooler and is further compressed in said boost compressor and cooled in the aftercooler, and the compressed air is charged into the air storage,

a compressed air storage charging using off-peak power mode of operation, wherein said turbine driving clutch structure of said at least one power shaft assembly is disengaged and said compressor driving clutch structure of said at least one power shaft assembly is engaged such that said at least one compressor is driven by said motor/generator, said second and third valve systems being closed and said first valve system being open so as to define an air and gas flow path where compressed air from said at least one compressor moves along said flow path structure and through said intercooler and is then further compressed in said boost compressor, cooled in the aftercooler and the compressed air is thereafter charged into the air storage, said motor/generator and said electric motor being coupled to and powered by an electric grid, and

an alternative intermediate load mode of operation, wherein air flow to said compressor of said at least one power shaft assembly is reduced and said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said at least one compressor, operating at part load, is driven by said motor/generator, said first valve system being closed and said second and third valve systems being open so as to define an air and gas flow path where compressed air from said at least one compressor passes through the bypass structure and is combined with compressed air from said air storage, the combined air moves to said recuperator and to the combustor and gas moves to the at least one turbine of said at least one power shaft assembly to produce a specified amount of intermediate power greater than base load.

19. The method according to claim 15, further including intercooling to reduce power consumption by a compressor of said at least one power shaft assembly.

20. A hybrid combustion turbine derivative power generation system comprising:

a modified combustion turbine derivative power generation system sized for base load operation and having at least one power shaft assembly having at least one compressor, at least one expansion turbine, and a double-ended motor/generator between said compressor and said turbine, said motor/generator being connected directly to an electric grid and selected to meet peak load requirements of said hybrid combustion turbine derivative power generation system and having turbine driving clutch structure on one end thereof and a compressor driving clutch structure on the other end thereof, said compressor driving clutch structure being operatively associated with said compressor so that said compressor is driven by said motor/generator when said compressor driving clutch structure is engaged and said turbine driving clutch structure being operatively associated with said turbine so that said motor/generator may be driven by said turbine when said turbine driven clutch structure is engaged, and a combustor feeding said expansion turbine, and

an additional system selected to meet peak load requirements of said hybrid combustion turbine derivative power generation system and having a boost compressor, an intercooler feeding cooled air to said boost compressor, an electric motor for driving said boost compressor, and aftercooler downstream of said boost compressor, a compressed air energy storage downstream of said aftercooler,

said additional system being integrated with said modified combustion turbine derivative power generation system by a flow path structure permitting communication between an outlet of said at least one compressor and an inlet to the said intercooler feeding said boost compressor, a connection structure permitting communication between an outlet of said air storage and an inlet to the combustor, a bypass structure having a first end coupled to said flow path structure and a second end coupled to said connection structure, said bypass structure permitting communication between an output of said at least one compressor and an inlet of said combustor,

said hybrid system further including

a first valve system for controlling air flow in said flow path structure and disposed between said at least one compressor and an inlet to said intercooler feeding said boost compressor,

a second valve system for controlling air flow in said connection structure and disposed between said air storage and said combustor, and

a third valve system for controlling air flow in said bypass structure,

said valve systems being constructed and arranged to provide various flow paths through said system and said turbine driving clutch structure and said compressor driving clutch being constructed and arranged to provide via said motor/generator (i) a base load power (ii) a peak load power which is greater than said base load power to meet peaking requirements by using air from said air storage, and (iii) an intermediate range of power loads between said base load power and said peak load power by using air from said air storage or a combination of air from said air storage and said compressor, and a charging mode of operation wherein said air storage is charged with compressed air.

21. The hybrid system according to claim 20, further including a recuperator, downstream of a coupling location of said second end of said bypass structure and said connection structure and, feeding said combustor of said at least one power shaft assembly.

22. The hybrid system according to claim 20, further including at least one intercooler to reduce power consumption by a compressor of said at least one power shaft assembly.

23. The hybrid system according to claim 21, wherein base load power is provided when said turbine driving clutch structure and said compressor driving clutch structure of each of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said motor/generator drives said at least one compressor of said at least one power shaft assembly, said first and second valve systems are closed and said third valve system is open so as to define an air and gas flow path through the at least one compressor, through said bypass structure through the recuperator and to the combustor feeding said at least one turbine, and gas moves to the at least one turbine.

24. The hybrid system according to claim 21, wherein peak or intermediate power is provided when said turbine driving clutch structure of said at least one power shaft assembly is engaged and said compressor driving clutch structure of said at least one power shaft assembly is disengaged such that said at least one turbine drives said motor/generator, said first and third valve system are closed and said second valve system is open so as to define an air and gas flow path where compressed air stored in said air storage moves through said recuperator to said combustor feeding gas to said at least one turbine of the at least one power shaft assembly such that substantially all power generated by said at least one turbine goes for electric power generation.

25. The hybrid system according to claim 21, wherein said valve systems and clutches are controllable to provide a compressed air storage self-charging mode of operation wherein said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said at least one compressor is driven by said motor/generator, said second valve system is closed and said first and third valve systems are open so as to define an air and gas flow path where compressed air from said at least one compressor is divided such that a portion of the air passes through the bypass structure to the recuperator and then to the combustor, the combustor feeding gas to the at least one turbine of the at least one power shaft assembly and another portion of the air moves along said flow path structure and through said intercooler and is further compressed in said boost compressor and cooled in the aftercooler, the air in said boost compressor is then charged into the air storage.

26. The hybrid system according to claim 21, wherein compressed air storage charging is provided when said turbine driving clutch structure of said at least one power shaft assembly is disengaged and said compressor driving clutch structure of said at least one power shaft assembly is engaged such that said at least one compressor is driven by said motor/generator, said second and third valve systems are closed and said first valve system is open so as to define an air flow path where compressed air from said at least one compressor moves along said flow path structure and through said intercooler and is then further compressed in said boost compressor and cooled in the aftercooler, the compressed air thereafter is charged into the air storage, said electric motor being coupled to and powered by the electric grid.

27. The hybrid system according to claim 21, wherein said valve systems and clutches are controllable to provide an alternative intermediate load mode of operation wherein air flow to said compressor of said at least one power shaft assembly is reduced and said turbine driving clutch structure and said compressor driving clutch structure of said at least one power shaft assembly are engaged such that said at least one turbine drives said motor/generator and said at least one compressor, operating at part load, is driven by said motor/generator, said first valve is closed and said second and third valves are open so as to define an air and gas flow path where compressed air from said at least one compressor passes through the bypass structure and is combined with compressed air from said air storage, said combined air moves to said recuperator to said combustor, the combustor feeding gas to said at least one turbine of said at least one power shaft assembly to produce a specified amount of power.

28. The hybrid system according to claim 21, further including providing a water heater connected along the turbine exhaust flow path to an outlet of said recuperator to preheat water, and including a saturator being fed with hot water and disposed in a flow path generally at a location downstream of said coupling location where compressed air from a highest pressure compressor of said at least one power shaft assembly and compressed air from the air storage combines.

29. The hybrid system according to claim 20, further including a heat recovery steam generator receiving an exhaust of a lowest pressure turbine to recover exhaust gas for generating steam.

30. The hybrid system according to claim 20, further including a steam turbine bottoming cycle with a heat recovery steam generator, said heat recovery steam generator being connected to said hybrid system to receive an exhaust gas of a lowest pressure turbine so as to recover an exhaust gas heat for generation of steam.