Cryogenic combined cycle power plant
In a cryogenic combined cycle power plant electric power drives a cryogenic refrigerator to store energy by cooling air to a liquid state for storage within tanks, followed by subsequent release of the stored energy by first pressurizing the liquid air, then regasifying the liquid air and raising the temperature of the regasified air at least in part with heat exhausted from a combustion turbine, and then expanding the heated regasified air through a hot gas expander to generate power. The expanded regasified air exhausted from the expander may be used to cool and make denser the inlet air to the combustion turbine. The combustion turbine exhaust gases may be used to drive an organic Rankine bottoming cycle. An alternative source of heat such as thermal storage, for example, may be used in place of or in addition to the combustion turbine.
1. A method of storing and recovering energy, the method comprising:
compressing a first stream of gaseous air with a compressor;
combusting the compressed gaseous air in a burner with a fuel to form a hot gaseous working fluid;
expanding the hot gaseous working fluid through a first turbine to form an exhaust gas stream and generate power;
producing liquid air in an electrically powered liquefaction process and storing the liquid air;
pressurizing the liquid air with a pump;
heating at least a portion of the pressurized liquid air to produce a second stream of gaseous air and heating the second stream of gaseous air, at least in part using heat from the exhaust gas stream from the first turbine in an air heater;
expanding the heated second stream of gaseous air through a second turbine to generate additional power; and
increasing the density of the first stream of gaseous air by heat exchange with the second stream of gaseous air or by momentum transfer from the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor.
2. The method of claim 1 , wherein comprising increasing the density of the first stream of gaseous air by cooling the first stream of gaseous air by heat exchange with the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor occurs before expanding the second stream of gaseous air through the second turbine.
3. The method of claim 1 , wherein increasing the density of the first stream of gaseous air by cooling the first stream of gaseous air by heat exchange with the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor occurs after expanding the second stream of gaseous air through the second turbine.
4. The method of claim 3 , comprising mixing at least a portion of the second stream of gaseous air with the first stream of gaseous air before or during compressing the first stream of gaseous air with the compressor and after expanding the second stream of gaseous air through the second turbine.
5. The method of claim 1 , comprising increasing the density of the first stream of air by momentum transfer with the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor.
6. The method of claim 5 , comprising mixing at least a portion of the second stream of gaseous air with the first stream of gaseous air before or during compressing the first stream of gaseous air with the compressor and after expanding the second stream of gaseous air through the second turbine, wherein:
the first stream of gaseous air has a pressure P 1 before compressing the first stream of gaseous air with the compressor; and
after expanding the second stream of gaseous air through the second turbine the second stream of air has a pressure P 2 greater than P 1 .
7. The method of claim 1 , comprising:
heating an organic working fluid to convert the organic working fluid from liquid to gaseous phase and then heating the gaseous phase organic working fluid, at least in part using heat from the exhaust gas stream from the first turbine in an organic working fluid heater;
expanding the heated gaseous organic working fluid through a third turbine to generate additional power; and
condensing in a condenser a first portion of the gaseous organic working fluid exhaust from the third turbine from gas phase to liquid phase by transferring heat from the gaseous organic working fluid exhaust to the liquid air or the second stream of gaseous air during heating of the pressurized liquid air or the second stream of gaseous air.
8. The method of claim 7 , wherein increasing the density of the first stream of gaseous air by cooling the first stream of gaseous air by heat exchange with the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor occurs before expanding the second stream of gaseous air through the second turbine.
9. The method of claim 7 , wherein increasing the density of the first stream of gaseous air by cooling the first stream of gaseous air by heat exchange with the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor occurs after expanding the second stream of gaseous air through the second turbine.
10. The method of claim 9 , comprising mixing at least a portion of the second stream of gaseous air with the first stream of gaseous air before or during compressing the first stream of gaseous air with the compressor and after expanding the second stream of gaseous air through the second turbine.
11. The method of claim 7 , comprising increasing the density of the first stream of air by momentum transfer with the second stream of gaseous air before or during compressing the first stream of gaseous air with the compressor.
12. A method of storing and recovering energy, the method comprising:
producing liquid air in an electrically powered liquefaction process and storing the liquid air;
pressurizing the liquid air with a pump;
heating at least a portion of the pressurized liquid air to produce gaseous air and then heating the gaseous air in an air heater;
expanding the heated gaseous air through a first turbine to generate power;
heating an organic working fluid to convert the organic working fluid from liquid to gaseous phase and then heating the gaseous phase organic working fluid in an organic working fluid heater;
expanding the heated gaseous organic working fluid through a second turbine to generate additional power;
condensing in a first condenser a first portion of the gaseous organic working fluid exhaust from the second turbine from gas phase to liquid phase by transferring heat from the first portion of gaseous organic working fluid exhaust from the second turbine to the liquid air or gaseous air during heating of the liquid air or the gaseous air;
expanding a second portion of the gaseous organic working fluid exhaust from the second turbine through a third turbine to generate additional power; and
condensing in a second condenser at least a first portion of the gaseous organic working fluid exhaust from the third turbine from gas phase to liquid phase by transferring heat from the first portion of gaseous organic working fluid exhaust from the third turbine to the liquid air or gaseous air during heating of the liquid air or the gaseous air;
wherein the first portion of the gaseous organic working fluid exhaust from the second turbine is condensed in the first condenser at a first pressure; and
the first portion of the gaseous organic working fluid exhaust from the third turbine is condensed in the second condenser at a second pressure lower than the first pressure.
13. The method of claim 12 , comprising pumping with a first pump the condensed first portion of the organic working fluid exhaust from the third turbine to the first pressure and combining it with the condensed first portion of the organic working fluid exhaust from the second turbine, then pumping with a second pump the combined condensed portions of organic working fluid to a third pressure higher than the first pressure.
14. The method of claim 13 , wherein:
the condensed first portion of the organic working fluid exhaust from the third turbine at the first pressure is a subcooled liquid; and
the condensed first portion of the organic working fluid exhaust from the second turbine is accompanied by gaseous organic working fluid exhaust from the second turbine that is condensed by contact with the subcooled condensed first portion of the organic working fluid exhaust from the third turbine when the condensed first portion of the organic working fluid exhaust from the third turbine and the condensed first portion of the organic working fluid exhaust from the second turbine are combined.
15. The method of claim 13 , wherein prior to being pumped to the third pressure the combined condensed first portion of the organic working fluid exhaust from the third turbine and condensed first portion of the organic working fluid exhaust from the second turbine is a subcooled liquid.
16. The method of claim 13 , comprising heating in a recuperator the condensed first portion of the organic working fluid exhaust from the third turbine by heat exchange with gaseous organic working fluid exhaust from the third turbine prior to combining the condensed first portion of the organic working fluid exhaust from the third turbine with the condensed first portion of the organic working fluid exhaust from the second turbine.
17. The method of claim 13 , wherein the third pressure is a super critical pressure.
18. The method of claim 12 , wherein heating the organic working fluid to convert it from liquid to gaseous phase and heating the gaseous phase organic working fluid comprises heating the organic working fluid with air exhausted from the first turbine.
19. The method of claim 12 , wherein heating the pressurized liquid air to produce gaseous air and heating the gaseous air in an air heater comprises heating with heat captured from the liquefaction process.
20. The method of claim 19 , wherein the heat captured from the liquefaction process is captured by chilling inlet air to the liquefaction process in an air cooler.