System and method for generating power using a supercritical fluid

A method of generating shaft power in a system comprising an air cycle and supercritical fluid cycle, comprising the steps of:

• a) burning a fossil fuel in air so as to produce a combustion gas including a first portion of said combustion gas and a second portion of said combustion gas;
• b) expanding said combustion gas in at least a first turbine so as to produce an expanded combustion gas, said expansion of said combustion gas generating a first turbine shaft power;
• c) compressing a supercritical fluid in a first compressor;
• d) flowing at least a portion of said compressed supercritical fluid through a first cross cycle heat exchanger, and flowing said combustion gas through said first cross cycle heat exchanger so as to transfer heat from said combustion gas to said compressed supercritical fluid so as to produce a heated compressed supercritical fluid, wherein said first portion of said combustion gas flows through said first cross cycle heat exchanger before the step of expanding said combustion gas in said first turbine and said second portion of said combustion gas flows through said first cross cycle heat exchanger after the step of expanding said combustion gas in said first turbine;
• e) expanding at least a portion of said heated compressed supercritical fluid in a second turbine so as to produce an expanded supercritical fluid, said expansion of said supercritical fluid generating a second turbine shaft power;
• and
• f) flowing at least a portion of said expanded supercritical fluid through a second cross cycle heat exchanger, and flowing said air through said second cross cycle heat exchanger prior to burning said fossil fuel in said air so as to transfer heat from said expanded supercritical fluid to said air.

A method of generating shaft power in a system comprising an air cycle and supercritical fluid cycle, comprising the steps of:

• a) burning a fossil fuel in air so as to produce a combustion gas;
• b) expanding said combustion gas in at least a first turbine so as to produce an expanded combustion gas, said expansion of said combustion gas generating a first turbine shaft power;
• c) compressing a supercritical fluid in a first compressor;
• d) flowing at least a portion of said compressed supercritical fluid through a first cross cycle heat exchanger, and flowing said combustion gas through said first cross cycle heat exchanger so as to transfer heat from said combustion gas to said compressed supercritical fluid so as to produce a heated compressed supercritical fluid;
• e) expanding at least a portion of said heated compressed supercritical fluid in a second turbine so as to produce an expanded supercritical fluid, said expansion of said supercritical fluid generating a second turbine shaft power;
• and
• f) flowing at least a portion of said expanded supercritical fluid through a second cross cycle heat exchanger, and flowing said air through said second cross cycle heat exchanger prior to burning said fossil fuel in said air so as to transfer heat from said expanded supercritical fluid to said air, wherein sufficient heat is transferred from said expanded supercritical fluid to said air in said second cross cycle heat exchanger to cool said expanded supercritical fluid to approximately the critical temperature of said supercritical fluid.

A method of generating shaft power in a system comprising an air cycle and supercritical fluid cycle, comprising the steps of:

• a) burning a fossil fuel in air so as to produce a combustion gas;
• b) expanding said combustion gas in at least a first turbine so as to produce an expanded combustion gas, said expansion of said combustion gas generating a first turbine shaft power, wherein the first turbine drives a first turbine shaft;
• c) compressing a supercritical fluid in a first compressor;
• d) flowing at least a portion of said compressed supercritical fluid through a first cross cycle heat exchanger, and flowing said combustion gas through said first cross cycle heat exchanger so as to transfer heat from said combustion gas to said compressed supercritical fluid so as to produce a heated compressed supercritical fluid;
• e) expanding at least a portion of said heated compressed supercritical fluid in a second turbine so as to produce an expanded supercritical fluid, said expansion of said supercritical fluid generating a second turbine shaft power, wherein said second turbine drives a second turbine shaft;
• f) transmitting torque from said second turbine shaft to an output shaft without contact between said second turbine shaft and said output shaft;
• and
• g) flowing at least a portion of said expanded supercritical fluid through a second cross cycle heat exchanger, and flowing said air through said second cross cycle heat exchanger prior to burning said fossil fuel in said air so as to transfer heat from said expanded supercritical fluid to said air.

A method of generating shaft power in a system comprising an air cycle and supercritical fluid cycle, comprising the steps of:

• a) burning a fossil fuel in air so as to produce a combustion gas;
• b) expanding said combustion gas in at least a first turbine so as to produce an expanded combustion gas, said expansion of said combustion gas generating a first turbine shaft power;
• c) compressing a supercritical fluid in a first compressor;
• d) flowing at least a portion of said compressed supercritical fluid through a first cross cycle heat exchanger, and flowing said combustion gas through said first cross cycle heat exchanger so as to transfer heat from said combustion gas to said compressed supercritical fluid so as to produce a heated compressed supercritical fluid and cooled combustion gas;
• e) transferring heat from said cooled combustion gas to a flow of water so as to heat said flow of water;
• f) expanding at least a portion of said heated compressed supercritical fluid in a second turbine so as to produce an expanded supercritical fluid, said expansion of said supercritical fluid generating a second turbine shaft power;
• and
• g) flowing at least a portion of said expanded supercritical fluid through a second cross cycle heat exchanger, and flowing said air through said second cross cycle heat exchanger prior to burning said fossil fuel in said air so as to transfer heat from said expanded supercritical fluid to said air.