SYSTEMS AND METHODS FOR POWER PRODUCTION USING NESTED CO2 CYCLES

• US 20170058712A1
• Filed: 08/31/2016
• Published: 03/02/2017
• Est. Priority Date: 09/01/2015
• Status: Active Grant

• Current Assignee: 8 Rivers Capital, LLC
• Original Assignee: 8 Rivers Capital, LLC
• Inventors: Allam, Rodney John, Forrest, Brock Alan
• Granted Patent: US 10,422,252 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01K 23/04 condensation heat from one cycle heating the fluid in another cycle
• 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: F01K 25/08 using special vapours
• CPC Class Codes: F01K 25/103 Carbon dioxide F01K25/065 takes precedence
• CPC Class Codes: F01K 7/16 the engines being only of turbine type the engines using steam of critical or overcritical pressure F01K7/32; the engines being of extraction or non-condensing type F01K7/34
• CPC Class Codes: F02C 1/007 combination of cycles
• CPC Class Codes: F02C 1/06 using reheated exhaust gas F02C1/08 takes precedence
• CPC Class Codes: F02C 1/08 Semi-closed cycles
• CPC Class Codes: F02C 3/34 with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle
• 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: F05D 2260/61 Removal of CO2 removal of CO2 from waste gases B01D53/62
• CPC Class Codes: F25J 2230/06 Adiabatic compressor, i.e. without interstage cooling
• CPC Class Codes: F25J 2240/70 Steam turbine, e.g. used in a Rankine cycle
• CPC Class Codes: F25J 2260/80 Integration in an installation using carbon dioxide, e.g. for EOR, sequestration, refrigeration etc.
• CPC Class Codes: F25J 3/04018 of main feed air
• CPC Class Codes: F25J 3/04024 of purified feed air, so-called boosted air
• CPC Class Codes: F25J 3/04133 Electrical motor as the prime mechanical driver
• CPC Class Codes: F25J 3/04145 Mechanically coupling of different compressors of the air fractionation process to the same driver(s)
• CPC Class Codes: F25J 3/04533 for the direct combustion of fuels in a power plant, so-called "oxyfuel combustion"
• CPC Class Codes: F25J 3/04618 for cooling an air stream fed to the air fractionation unit
• CPC Class Codes: Y02E 20/16 : Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 20/34 : Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Abstract

The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO₂ as a working fluid may be combined with a second cycle wherein a compressed CO₂ stream from the power production cycle can be heated and expanded to produce additional power and to provide additional heating to the power production cycle.

Claims

1. A power production method comprising:

operating a first power production cycle wherein a recycled CO₂ stream is subjected to repeated compression, heating, combustion, expansion for power production, and cooling; and

operating a second power production cycle wherein compressed recycled CO₂ from the first power production cycle is heated with a heat source that is independent of the first power production cycle, expanded for power production, and recombined with the recycled CO₂ stream in the first power production cycle.

2. The power production method of claim 1, wherein the heating in the first power production cycle includes receiving heat provided to the recycled CO₂ in the second power production cycle.

3. The power production method of claim 1, wherein the heat source in the second power production cycle is one or more of a combustion heat source, a solar heat source, a nuclear heat source, a geothermal heat source, and an industrial waste heat source.

4. A method of power production comprising:

carrying out a first cycle that includes;

expanding a work stream comprising recycled CO₂ across a first turbine to produce a first quantity of power;

withdrawing heat from the work stream in a recuperative heat exchanger;

compressing the work stream;

reheating the work stream using withdrawn heat in the recuperative heat exchanger; and

superheating the compressed work stream in a combustor; and

carrying out a nested cycle wherein compressed work stream from the first cycle is heated with a heat source that is independent of the combustor and the recuperative heat exchanger and is expanded across a second turbine to produce a second quantity of power.

5. The method of power production of claim 4, wherein the expanded work stream from the nested cycle is used to add heat to the work stream in the first cycle after the compressing and before the superheating.

6. The power production method of claim 4, wherein the heat source in the nested cycle is one or more of a combustion heat source, a solar heat source, a nuclear heat source, a geothermal heat source, and an industrial waste heat source.

7. A method for improving the efficiency of a power production cycle, the method comprising:

operating the power production cycle so that compressed, recycled CO₂ is passed through a combustor wherein a carbonaceous fuel is combusted with an oxidant to produce an exhaust stream comprising recycled CO₂;

the exhaust stream is expanded across a turbine to produce power and form a turbine exhaust stream comprising recycled CO₂;

the turbine exhaust stream is cooled in a recuperative heat exchanger;

the cooled turbine exhaust stream is passed through a separator to separate the recycled CO₂;

the recycled CO₂ is compressed; and

the compressed recycled CO₂ is heated by passage through the recuperative heat exchanger against the turbine exhaust stream; and

adding further heating to the compressed recycled CO₂ above the level of heating that is available from the turbine exhaust stream, the further heating being provided by withdrawing a portion of the compressed recycled CO₂, heating the withdrawn portion of compressed recycled CO₂ with a heat source that is independent of the power production cycle, and transferring heat from the withdrawn and heated compressed recycled CO₂ to the remaining portion of the compressed recycled CO₂ in the power production cycle.

8. The method of claim 7, comprising passing the withdrawn and heated compressed recycled CO₂ through the recuperative heat exchanger so as to transfer heat to the compressed recycled CO₂ therein.

9. The method of claim 7, comprising passing the withdrawn and heated compressed recycled CO₂ through a secondary heat exchanger to heat a recycled CO₂ sidestream that is thereafter combined with the remaining portion of the compressed recycled CO₂ in the recuperative heat exchanger.

10. The method of claim 7, comprising expanding the withdrawn and heated compressed recycled CO₂ across a second turbine to produce power.

11. A power production system comprising:

a compressor configured to compress a CO₂ stream to a pressure of at least about 100 bar (10 MPa);

a combustor downstream from the compressor;

a first turbine downstream from the combustor and upstream from the compressor;

a first heat exchanger positioned to receive a stream from the compressor and to receive a separate stream from the turbine and configured to transfer heat between the streams;

a second turbine downstream from the compressor; and

a second heat exchanger positioned to receive a stream from the compressor and to receive a separate stream from a heat source.

12. The power production system of claim 11, wherein the heat source for the separate stream received by the second heat exchanger is one or more of a combustion heat source, a solar heat source, a nuclear heat source, a geothermal heat source, and an industrial waste heat source.