System and method for high efficiency power generation using a carbon dioxide circulating working fluid

Patent metadata

Field	Value
Publication number	US-10975766-B2
Application number	US-201816006974-A
Country	US
Kind code	B2
Filing date	Jun 13, 2018
Priority date	Feb 26, 2009
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO 2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO 2 circulating fluid. Fuel derived CO 2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

First claim

The invention claimed is:

1. A method of power generation comprising:
expanding a compressed recycle CO 2 stream at a pressure of at least about 12 MPa across a series of a first turbine and a last turbine over a pressure ratio of at least about 20 so as to output from the last turbine a last turbine discharge stream;
heating a discharge stream from the first turbine prior to passage into the last turbine in a combustor by combusting a hydrocarbon or carbonaceous fuel in the presence of an oxidant and the first turbine discharge stream so as to form a combustor exhaust stream at a pressure of at least about 10 MPa and a temperature of at least about 800° C.;
cooling the last turbine discharge stream in a recuperator heat exchanger to form a cooled turbine discharge stream;
isolating at least a portion of CO 2 from the cooled turbine discharge stream to form a recycle CO 2 stream;
compressing the recycle CO 2 stream to form the compressed recycle CO 2 stream;
heating at least a portion of the compressed recycle CO 2 stream using heat withdrawn from the last turbine discharge stream and heating at least another portion of the compressed recycle CO 2 stream with more heat from a source other than the heat withdrawn from the turbine discharge stream; and
passing the compressed recycle CO 2 stream to the series of the first turbine and the last turbine.

2. The method of claim 1 , wherein the last turbine discharge stream is at a pressure of less than about 0.15 MPa.

3. The method of claim 1 , wherein the compressing comprises passing the recycle CO 2 stream through a multistage compressor that compresses the recycle CO 2 stream to a pressure of at least 5.75 MPa and then through a pump that increases the pressure to at least about 12 MPa.

4. The method of claim 3 , wherein the multistage compressor comprises a first compressor including at least two units that are intercooled.

5. The method of claim 4 , wherein the multistage compressor comprises a second compressor.

6. The method of claim 5 , further comprising intercooling between the first compressor and the second compressor.

7. The method of claim 5 , wherein the recycle CO 2 stream exiting the first compressor is at a pressure of at least 3 MPa.

8. The method of claim 5 , wherein the recycle CO 2 stream exiting the second compressor is at a pressure of at least 5.75 MPa.

9. The method of claim 1 , further comprising withdrawing a portion of the last turbine discharge stream upstream from the recuperator heat exchanger to form a withdrawn portion.

10. The method of claim 9 , further comprising passing the withdrawn portion of the last turbine discharge stream through one or more further heat exchangers so as to provide heat to one or more further streams.

11. The method of claim 9 , wherein the one or more further streams receiving heat from the withdrawn portion of the last turbine discharge stream is one or both of the hydrocarbon or carbonaceous fuel and the oxygen input to the combustor or to an optional further combustor.

12. The method of claim 1 , further comprising withdrawing a side stream from the compressed recycle CO 2 stream.

13. The method of claim 12 , wherein the more heat from the source other than the heat withdrawn from the turbine discharge stream is added to the withdrawn side stream of compressed recycle CO 2 .

14. The method of claim 1 , wherein the combination of the heat withdrawn from the last turbine discharge stream and the more heat from the source other than the heat withdrawn from the turbine discharge stream is sufficient so that a temperature difference between the recycle CO 2 expanded across the series of the first turbine and the last turbine and a temperature of the last turbine discharge stream by less than about 50° C.

15. The method of claim 1 , wherein the more heat from the source other than the heat withdrawn from the turbine discharge stream is from an air separation unit.

16. The method of claim 1 , further comprising passing the compressed recycle CO2 stream into a further combustor prior to expanding the compressed recycle CO2 stream across the series of the first turbine and the last turbine.

17. The method of claim 16 , wherein an exhaust stream from the further combustor enters the first turbine at a pressure of about 12 MPa to about 60 MPa.

18. The method of claim 1 , further comprising passing the compressed recycle CO2 stream into a liquefaction heat exchanger so as to liquefy the compressed recycle CO2 stream against a stream of high pressure liquid natural gas (LNG) and increase a temperature of the LNG stream.

19. The method of claim 18 , wherein the LNG stream is at a pressure of about 4 MPa to about 7 MPa and a temperature of about −160° C. to about −140° C.

20. The method of claim 18 , wherein the LNG stream exiting the liquefaction heat exchanger is at a temperature that is within about 10° C. to about 20° C. of an inlet temperature of the compressed recycle CO 2 stream into the liquefaction heat exchanger.

21. The method of claim 1 , wherein one or both of the first turbine and the last turbine are in a mechanical working connection with one or more further components used in a method such that a shaft power provided by one or both of the first turbine and the last turbine is mechanically transferred to the one or more further components.

22. The method of claim 21 , wherein the one or more further components is a compressor, a pump, or an air separation unit.

23. The method of claim 21 , wherein one or both of the first turbine and the last turbine also provide the shaft power to a generator.

24. The method of claim 1 , wherein one or both of the first turbine and the last turbine comprises one or more radial turbines.

Assignees

• 8 Rivers Capital Llc

Inventors

• Allam Rodney John
• Palmer Miles R
• Brown Jr Glenn William
• Fetvedt Jeremy Eron
• Forrest Brock Alan

Classifications

• F01K13/00 Primary

  General layout or general methods of operation of complete plants · CPC title

• F23L2900/07003

  Controlling the inert gas supply · CPC title

• F22B35/12

  operating at critical or supercritical pressure · CPC title

• F25J3/04545

  for the gasification of solid or heavy liquid fuels, e.g. integrated gasification combined cycle [IGCC] · CPC title

• F25J3/04533

  for the direct combustion of fuels in a power plant, so-called "oxyfuel combustion" · CPC title