IGCC design and operation for maximum plant output and minimum heat rate

• US 20080087022A1
• Filed: 10/13/2006
• Published: 04/17/2008
• Est. Priority Date: 10/13/2006
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Power Generation, Inc.
• Inventors: Briesch, Michael Scot, Sullivan, Terrence Blaise
• Granted Patent: US 7,874,139 B2
• Time in Patent Office: Days
• US Class Current: 60/772
• CPC Class Codes: F01K 23/068 in combination with an oxygen producing plant, e.g. an air separation plant
• CPC Class Codes: F02C 3/28 using a separate gas producer for gasifying the fuel before combustion
• CPC Class Codes: F02C 9/40 specially adapted to the use of a special fuel or a plurality of fuels
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 20/18 Integrated gasification combined cycle [IGCC], e.g. combined with carbon capture and storage [CCS]

Abstract

A system and method for operating an integrated gasification combined cycle (IGCC) gas turbine system that utilizes the fuel stream as a means of controlling the operation of the IGCC to achieve a target output and efficiency. The methods and systems enable the IGCC to be operated at reduced output, but without a corresponding drop in efficiency as compared to prior art gas turbine systems. Conversely, the IGCC may be operated at higher outputs. The methods and systems achieve the target output and efficiency by adjusting the chemical potential energy, sensible energy, or both of a fuel stream entering the combustion turbine. The chemical potential energy and sensible energy may be manually or automatically controlled.

Claims

1. A method for operating an integrated gasification combined cycle gas turbine having a design operation point for a chemical potential energy of a fuel stream, comprising:

determining a target output and target efficiency, whereby at least one of the target output and the target efficiency is different than an output or efficiency design operation point of an integrated gasification combined cycle gas turbine; and

adjusting a chemical potential energy of a fuel stream to achieve the target output and target efficiency.

2. The method of claim 1, further comprising automatically adjusting the chemical potential energy of the fuel stream to achieve the target output and target efficiency.

3. The method of claim 1, wherein the chemical potential energy of the fuel stream is adjusted by changing a heating value of the fuel stream.

4. The method of claim 3, wherein the heating value of the fuel stream is increased in order to decrease output or increase efficiency of the integrated gasification combined cycle gas turbine.

5. The method of claim 3, wherein the heating value of the fuel stream is decreased in order to increase output or decrease efficiency of the integrated gasification combined cycle gas turbine.

6. The method of claim 3, wherein the heating value of the fuel stream is adjusted by mixing the fuel stream with a mixing stream having a heating value different from the heating value of the fuel stream.

7. The method of claim 6, wherein the mixing stream comprises a fluid selected from the group consisting of nitrogen, water, steam, natural gas, synthesis gas, and combinations thereof.

8. A method for operating an integrated gasification combined cycle gas turbine having a design operation point for a sensible energy of a fuel stream, comprising:

determining a target output and target efficiency, whereby at least one of the target output and the target efficiency is different than an output or efficiency design operation point of an integrated gasification combined cycle gas turbine; and

adjusting a sensible energy of a fuel stream to achieve the target output or target efficiency.

9. The method of claim 8, wherein said integrated gasification combined cycle gas turbine has a design operation point for a chemical potential energy of the fuel stream, further comprising adjusting the chemical potential energy of the fuel stream to achieve the target output or efficiency.

10. The method of claim 8, further comprising automatically adjusting the sensible energy of the fuel stream to achieve the target output or efficiency.

11. The method of claim 8, wherein the sensible energy of the fuel stream is adjusted by changing a temperature of the fuel stream.

12. The method of claim 11, wherein the fuel stream temperature is increased in order to reduce output or increase efficiency of the integrated gasification combined cycle gas turbine.

13. The method of claim 11, wherein the fuel stream temperature is decreased in order to increase output or reduce efficiency of the integrated gasification combined cycle gas turbine.

14. The method of claim 11, wherein the fuel stream temperature is adjusted by mixing the fuel stream with a mixing stream comprising a gas selected from the group consisting of nitrogen, water, steam, natural gas, synthesis gas, and combinations thereof.

15. The method of claim 11, wherein the fuel stream temperature is adjusted using a closed system heat exchanger and an exchanger stream having a temperature different from the fuel stream.

16. The method of claim 15, wherein the exchanger stream comprises a fluid selected from the group consisting of synthesis gas, steam, nitrogen gas, flue gas, water, air, and combinations thereof.

17. An integrated gasification combined cycle gas turbine system comprising:

a combustor;

a turbine;

a fuel stream having a design operation point for a chemical potential energy and a sensible energy of a fuel stream, the fuel being combusted in the combustor and expanded in the turbine to generate power output; and

a mechanism for adjusting the chemical potential energy or the sensible energy of the fuel stream prior to entering the combustor.

18. The system of claim 17, wherein the sensible energy of the fuel stream is adjusted by adjusting the temperature of the fuel stream and the mechanism for adjusting the temperature is a closed system heat exchanger or a mixing valve used to combine the fuel stream with a mixing stream having a temperature different from the fuel stream.

19. The system of claim 17, wherein the chemical potential energy of the fuel stream is adjusted by adjusting the heating value of the fuel stream and the mechanism for adjusting the heating value comprises a mixing valve used to combine the fuel stream with a mixing stream having a different heating value than the fuel stream.

20. The system of claim 17, further comprising an automatic control system for maintaining the chemical potential energy or the sensible energy of the fuel stream at a target value other than the design operation point.