Systems and methods for co2 capture

Abstract

The present disclosure relates to the separation of CO 2 from a gas mixture. The CO 2 may be removed by cooling the gas mixture such that the CO 2 can be removed as a solid or liquid. In various embodiments the gas mixture from which the CO 2 is removed may include exhaust gases generated as part of a combustion process, such as may be employed in a power generation process, though the gas mixture may be any gas mixture that includes CO 2 .

1 . A power-generating system comprising:
 a boiler suitable for combusting air and fuel to provide heat to a steam cycle interfaced with the boiler, wherein an exhaust gas containing CO 2  is generated when air and fuel are combusted;   a first cooling stage configured to receive the exhaust gas from the boiler and to cool the exhaust gas such that some or all of the water or other impurities is removed from the exhaust gas;   a second cooling stage configured to receive the exhaust gas after the exhaust gas leaves the first cooling stage and to cool the exhaust gas;   a first expansion component configured to expand the exhaust gas after the exhaust gas leaves the second cooling stage so that the exhaust gas is sufficiently reduced in temperature that CO 2  drops out of the gas mixture as a liquid or solid; and   a CO 2  separation stage configured to separate the solid or liquid phase CO 2  to generate a CO 2  lean gas mixture.   
     
     
         2 . The power-generating system of  claim 1 , wherein the boiler operates with combustion gasses at high pressure. 
     
     
         3 . The power-generating system of  claim 1 , comprising a first compressor component configured to compress air entering the boiler. 
     
     
         4 . The power-generating system of  claim 1 , comprising a second compressor component configured to compress exhaust gas between the first cooling stage and the second cooling stage. 
     
     
         5 . The power-generating system of  claim 1 , comprising a third cooling stage configured to receive the exhaust gas after the exhaust gas leaves the second cooling stage and to cool the exhaust gas prior to the exhaust gas entering the first expansion component. 
     
     
         6 . The power-generating system of  claim 1 , wherein one or more of the cooling stages comprise a heat exchanger. 
     
     
         7 . The power-generating system of  claim 1 , wherein the CO 2  separation stage comprises one or more of a vapor-solid separator or a vapor-liquid separator. 
     
     
         8 . The power-generating system of  claim 1 , comprising a liquefying component configured to apply pressure and heat to the separated CO 2  to convert the CO 2  to a liquid phase if not already in a liquid phase. 
     
     
         9 . The power-generating system of  claim 8 , wherein the liquefying component comprises one or more of a posimetric pump or a solid compressor. 
     
     
         10 . The power-generating system of  claim 8  wherein the application of pressure and heat to the separated CO 2  is thermally integrated with the cooling of the exhaust gas. 
     
     
         11 . The power-generating system of  claim 1 , comprising a second expansion component configured to receive and expand the CO 2  lean gas mixture after the CO 2  lean gas mixture is heated by one or both of a heat exchanger associated with the steam cycle or the boiler. 
     
     
         12 . A power-generating system comprising:
 a turbine engine configured to combust air and fuel and to generate an exhaust gas containing CO 2  when the air and fuel are combusted;   one or more heat exchangers configured to receive the exhaust gas generated by the turbine engine and to cool the exhaust gas;   an expansion component configured to expand the exhaust gas after the exhaust gas leaves at least one of the first heat exchangers such that the temperature of the exhaust gas is reduced; and   a CO 2  separation stage configured to separate solid or liquid phase CO 2  from the exhaust gas to generate a CO 2  lean gas mixture.   
     
     
         13 . The power-generating system of  claim 12 , wherein at least one of the heat exchangers comprise a heat recovery steam generator. 
     
     
         14 . The power-generating system of  claim 12 , wherein some or all of the water or other impurities is removed from the exhaust gas upon the exhaust gas being cooled by the one or more heat exchangers. 
     
     
         15 . The power-generating system of  claim 12 , wherein the turbine engine comprises a gas turbine engine. 
     
     
         16 . The power generating system of  claim 12 , wherein at least one of the one or more heat exchangers comprises an intercooler. 
     
     
         17 . The power generating system of  claim 12 , wherein the CO 2  lean gas mixture is provided as an input to the turbine engine. 
     
     
         18 . The power generating system of  claim 12 , wherein the CO 2  lean gas mixture is used to cool one or more inlets, heat exchangers or intercoolers of the power-generating system. 
     
     
         19 . The power generating system of  claim 12 , comprising:
 a compressor disposed between a first heat exchanger and a second heat exchanger, wherein the compressor is configured to receive the exhaust gas from the first heat exchanger and to compress the exhaust gas prior to entering second heat exchanger.   
     
     
         20 . The power generating system of  claim 12 , comprising:
 at least one air drying system configured to dry air entering the turbine engine or configured to dry the exhaust gas entering the expansion component.   
     
     
         21 . The power generating system of  claim 12 , comprising:
 an inlet heat exchanger configured to cool air entering the turbine engine.   
     
     
         22 . The power generating system of  claim 12 , wherein at least one heat exchanger is configured to receive the exhaust gas at a pressure of about 1.1 bar to about 10 bar and to cool the exhaust gas prior to the exhaust gas entering a downstream heat exchanger. 
     
     
         23 . The power generating system of  claim 12 , comprising:
 a natural gas circuit positioned to cool at least one heat exchanger, wherein natural gas approaches the heat exchanger to be cooled in a liquefied state and moves away from the heat exchanger in a gasified state.   
     
     
         24 . The power-generating system of  claim 12 , comprising a liquefying component configured to apply pressure and heat to the separated CO 2  to convert the CO 2  to a liquid phase if not already in a liquid phase. 
     
     
         25 . The power-generating system of  claim 24 , wherein the liquefying component comprises one or more of a posimetric pump or a solid compressor. 
     
     
         26 . The power-generating system of  claim 12  wherein the application of pressure and heat to the separated CO 2  is thermally integrated with the cooling of the exhaust gas. 
     
     
         27 . A cooling system comprising:
 a CO 2  separation system configured to remove some or all of the CO 2  from an exhaust gas stream generated by a combustion process to generate a CO 2  lean gas stream;   one or more conduits positioned to route the CO 2  lean gas stream to one or more components of a system or machine, wherein the one or more components are at a temperature greater than the CO 2  lean gas stream such that the one or more components are cooled by the CO 2  lean gas stream.   
     
     
         28 . The cooling system of  claim 27 , wherein the one or more components comprise heat exchangers for removing heat from the exhaust gas stream. 
     
     
         29 . The cooling system of  claim 27 , wherein the one or more components comprise heat exchangers or air inlets for reducing the temperature of air entering a turbine engine that generates the exhaust gas stream.