Combined Cycle Power Plant Including A Refrigeration Cycle

• US 20110088399A1
• Filed: 10/15/2009
• Published: 04/21/2011
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Energy Incorporated (Siemens AG)
• Inventors: McLaurin, Keith B., Briesch, Michael S.
• Granted Patent: US 8,286,431 B2
• Time in Patent Office: Days
• US Class Current: 60/728
• CPC Class Codes: F01K 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: F02C 6/18 using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Abstract

A method and system for augmenting the output of a combined cycle power plant having a gas turbine driving a generator, a heat recovery steam generator that recovers exhaust heat from the gas turbine to drive a steam turbine also driving a generator, and a refrigeration element that is powered by available energy in steam exhausted from the steam turbine to cool water. The refrigeration element employs a substantially closed cycle refrigeration system that, in a preferred embodiment, is either an absorption chilling system or a thermal compression chilling system. The refrigeration element provides cool water to an inlet chiller arranged to chill inlet to the gas turbine to augment the power output of the gas turbine and the water is recirculated to be chilled and used again. Since the refrigeration cycle is substantially closed, little or no additional plant water consumption is imposed on the power plant.

Claims

1. A power plant, comprising:

a combustion turbine system having an inlet receiving inlet air and exhausting expanded combustion gas, the combustion turbine system coupled to an electric generator;

an inlet chiller for chilling inlet air before the air is received by the inlet of the combustion turbine system to augment a power output of the power plant;

a heat recovery steam generator for receiving the expanded combustion gas and extracting heat therefrom to produce usable steam;

a steam turbine system coupled to an electric generator, the steam turbine system receiving the usable steam from the heat recovery steam generator and exhausting steam at super-atmospheric pressure; and

a refrigeration element configured to receive at least a portion of the exhausted steam from the steam turbine and to extract energy from the steam to drive a substantially closed refrigeration cycle that chills a fluid,

the chilled fluid being circulated through the inlet chiller to chill inlet air, wherein a quantity of water available for use in the power plant is increased by collecting moisture that has condensed on the refrigeration element.

2. A power plant as claimed in claim 1, wherein the refrigeration cycle comprises an absorption chiller cycle.

3. A power plant as claimed in claim 2, wherein the absorption chiller cycle comprises a generator for extracting heat from the received steam to boil a salt solution and produce a refrigerant vapor.

4. A power plant as claimed in claim 3, wherein the absorption chiller cycle further comprises a condenser configured to receive a refrigerant vapor and condense the vapor to a refrigerant liquid.

5. A power plant as claimed in claim 4, wherein the absorption chiller cycle further comprises an evaporator configured to receive the refrigerant liquid and to vacuum evaporate the liquid, the evaporating liquid cooling the chilled fluid.

6. A power plant as claimed in claim 5, wherein the absorption chiller cycle further comprises an absorber configured to return a dilute salt solution back to the generator and complete the cycle.

7. A power plant as claimed in claim 1, wherein the refrigeration cycle is a thermal compression cycle.

8. A power plant as claimed in claim 7, wherein the thermal compression cycle comprises a steam jet vacuum ejector for extracting energy from the received steam at super-atmospheric pressure.

9. A power plant as claimed in claim 8, wherein a velocity of the super-atmospheric steam is increased as the steam flows through the steam jet vacuum ejector.

10. A power plant as claimed in claim 9, wherein the thermal compression cycle further comprises the fluid in an evaporator tank, the evaporator tank in communication with the steam jet vacuum ejector.

11. A power plant as claimed in claim 10, wherein a vacuum is created and maintained in the evaporator tank by the increased velocity of the steam, the vacuum causing a portion of the fluid to flash and undergo a state change to a vapor.

12. A power plant as claimed in claim 11, wherein the flashing of the fluid in the evaporator tank chills the remaining fluid.

13. A power plant as claimed in claim 12, wherein the steam jet ejector comprises a diffuser through which the steam expands and is exhausted.

14. A power plant as claimed in claim 1, wherein potable water is extracted from a plurality of external surfaces of the refrigeration element.

15. A method of augmenting power production of a turbine driven power plant, the method comprising the steps of:

(a) directing a portion of the exhaust of a turbine of the power plant to a refrigeration element;

(b) in the refrigeration element, extracting energy from the exhaust to drive a substantially closed refrigeration cycle to chill a fluid;

(c) directing the chilled fluid to an inlet cooler for cooling inlet air; and

(d) directing the cooled inlet air to an inlet of a turbine of the power plant to augment a power output of the turbine, wherein operating the refrigeration element increases a quantity of water used in the power plant and the quantity of water is available for collection and use in a plant process.

16. The method of claim 15, wherein the turbine of step (d) is a combustion turbine.

17. The method of claim 15, wherein the turbine of step (a) is a super-atmospheric steam turbine.

18. The method of claim 15, where in step (b) the substantially closed refrigeration cycle comprises either an absorption chiller cycle or a thermal compression cycle.

19. A power plant operating in an arid environment comprising a Brayton cycle element, a Rankine cycle element, a refrigeration element chilling a fluid, and an inlet chiller receiving the chilled fluid to cool inlet air used in the Brayton cycle element, the refrigeration element employing a substantially closed refrigeration cycle to chill the fluid.

20. The power plant as claimed in claim 19, wherein the substantially closed refrigeration element comprises either an absorption chiller cycle or a thermal compression cycle.