Co2 power cycle with adiabatic compression

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, which can be heated and expanded to produce additional power and to provide additional heating to the power production cycle.

1 . A power production cycle comprising:
 combusting a hydrocarbon fuel stream with oxygen to produce combustion products;   combining the combustion products with a preheated circulating pressurized CO 2  stream to form a mixture; and   feeding the mixture to a power turbine to create a discharge, the discharge then being fed into a recuperative heat exchanger to preheat the circulating pressurized CO 2  stream;   wherein an adiabatic compression system is used to adiabatically compress the circulating pressurized CO 2  stream and the oxygen from a lesser pressure to a greater inlet pressure of the power turbine and to heat the circulating pressurized CO 2  stream and the oxygen;   wherein the circulating pressurized CO 2  stream and the oxygen leaving the adiabatic compression system enter the recuperative heat exchanger where they are further heated against the discharge from the power turbine; and   wherein the discharge from the power turbine leaving the recuperative heat exchanger enters a second heat exchanger that heats one or more fluid streams supplied from one or more external sources.   
     
     
         2 . The power production cycle according to  claim 1 , wherein the one or more fluid streams heated in the second heat exchanger comprise one or both of boiler feed-water and process steam delivered from a steam-based power cycle. 
     
     
         3 . The power production cycle according to  claim 1 , wherein the one or more fluid streams heated in the second heat exchanger comprises a pressurized water flow. 
     
     
         4 . The power production cycle according to  claim 1 , wherein the adiabatic compression system comprises a CO 2  compressor and a compressor for a mixture of the oxygen and CO 2 . 
     
     
         5 . The power production cycle according to  claim 4 , wherein a separate stream of CO 2  is taken from the discharge of the CO 2  compressor and introduced into the power turbine as a cooling fluid. 
     
     
         6 . The power production cycle according to  claim 4 , wherein the mixture comprises about 15% to about 60% molar oxygen. 
     
     
         7 . The power production cycle according to  claim 1 , wherein the discharge from the power turbine leaving the second heat exchanger is cooled to near ambient temperature by ambient cooling means, and wherein net product water and CO 2  are removed before entering the adiabatic compression system. 
     
     
         8 . The power production cycle according to  claim 1 , further comprising preheating the hydrocarbon fuel stream in the second heat exchanger and then heating the hydrocarbon fuel stream in the recuperative heat exchanger before combusting the hydrocarbon fuel stream. 
     
     
         9 . The power production cycle according to  claim 1 , wherein the hydrocarbon fuel stream comprises natural gas that has been compressed to the inlet pressure of the power turbine. 
     
     
         10 . The power production cycle according to  claim 1 , wherein an inlet pressure of the adiabatic compression system is in a range of about 4 bar (0.4 MPa) to about 40 bar (4 MPa). 
     
     
         11 . The power production cycle according to  claim 1 , wherein an inlet temperature of the power producing turbine is in a range of about 1000° C. to about 1600° C. 
     
     
         12 . The power production cycle according to  claim 1 , wherein the inlet pressure of the power producing turbine is in a range of about 200 bar (20 MPa) to about 500 bar (50 MPa). 
     
     
         13 . The power production cycle according to  claim 1 , wherein a pressure ratio of the power turbine is in a range of about 15 to about 40. 
     
     
         14 . The power production cycle according to  claim 1 , wherein substantially all of the circulating pressurized CO 2  stream is adiabatically compressed from the lesser pressure to the greater inlet pressure of the power turbine. 
     
     
         15 . The power production cycle according to  claim 1 , wherein near 100% of carbon in the hydrocarbon fuel stream that is combusted is captured. 
     
     
         16 . The power production cycle according to  claim 1 , wherein the mixture of the combustion products and the preheated circulating pressurized CO 2  stream comprises about 0.1% to about 4.0% molar oxygen. 
     
     
         17 . The power production cycle according to  claim 1 , wherein the hydrocarbon fuel stream comprises natural gas. 
     
     
         18 . The power production cycle according to  claim 1 , wherein the hydrocarbon fuel stream comprises syngas. 
     
     
         19 . A power production cycle comprising:
 combusting a hydrocarbon fuel stream with oxygen to produce combustion products;   combining the combustion products with a preheated circulating pressurized CO 2  stream to form a mixture; and   feeding the mixture to a power turbine to create a discharge, the discharge then being fed into a recuperative heat exchanger to preheat the circulating pressurized CO 2  stream;   wherein an adiabatic compression system is used to adiabatically compress substantially all of the circulating pressurized CO 2  stream and the oxygen from a lesser pressure to a greater inlet pressure of the power turbine and to heat substantially all of the circulating pressurized CO 2  stream and the oxygen, the adiabatic compression system comprising a CO 2  compressor and a compressor for a mixture of the oxygen and CO 2 , and the inlet pressure of the power turbine being in a range of about 200 bar (20 MPa) to about 500 bar (50 MPa);   
       wherein the circulating pressurized CO 2  stream and the oxygen leaving the adiabatic compression system enter the recuperative heat exchanger where they are further heated against the discharge from the power turbine; and
 wherein the discharge from the power turbine leaving the recuperative heat exchanger enters a second heat exchanger that heats one or more fluid streams supplied from one or more external sources.