System and method for waste heat utilization in carbon dioxide capture systems in power plants

Abstract

Disclosed herein is a system comprising an absorber; the absorber permitting contact between a flue gas stream that comprises carbon dioxide and a solvent to produce a carbon dioxide rich solvent; a regenerator disposed downstream of the absorber; the regenerator being operative to dissociate the carbon dioxide from the solvent; and a compression system disposed downstream of the regenerator comprising a plurality of compression stages; where each compression stage comprises a compressor that is operative to pressurize the carbon dioxide that is dissociated from the solvent; and where at least some of the compression stages comprise a knockout tank disposed upstream of the compressor and an intercooling heat exchanger disposed downstream of the compressor; where the knockout tank is operative to remove liquid present in the carbon dioxide and where the intercooling heat exchanger is operative to remove heat generated during the pressurizing of the carbon.

What is claimed is: 
     
         1 . A system comprising:
 an absorber; the absorber permitting contact between a flue gas stream that comprises carbon dioxide and a solvent to produce a carbon dioxide rich solvent;   a regenerator disposed downstream of the absorber; the regenerator being operative to dissociate the carbon dioxide from the solvent; and   a compression system disposed downstream of the regenerator comprising:   a plurality of compression stages; where each compression stage comprises a compressor that is operative to pressurize the carbon dioxide that is dissociated from the solvent; and where at least some of the compression stages comprise a knockout tank disposed upstream of the compressor and an intercooling heat exchanger disposed downstream of the compressor; where the knockout tank is operative to remove liquid present in the carbon dioxide and where the intercooling heat exchanger is operative to remove heat generated during the pressurizing of the carbon dioxide.   
     
     
         2 . The system of  claim 1 , where each compression stage comprises the knockout tank and the intercooling heat exchanger. 
     
     
         3 . The system of  claim 2 , where the compression system comprises at least two compression stages that comprise the knockout tank and the intercooling heat exchanger. 
     
     
         4 . The system of  claim 2 , where the compression system comprises at least four compression stages that comprise the knockout tank and the intercooling heat exchanger. 
     
     
         5 . The system of  claim 2 , where the compression system further comprises a heat exchanger disposed downstream of the compressor and upstream of the intercooling heat exchanger. 
     
     
         6 . The system of  claim 1 , where the intercooling heat exchanger lies downstream of a first compressor and upstream of a second compressor. 
     
     
         7 . The system of  claim 1 , where at least one compression stage comprises an after-cooling heat exchanger; where the after-cooling heat exchanger lies downstream of a final compressor. 
     
     
         8 . The system of  claim 1 , where cooling water from a plurality of intercooling heat exchangers is discharged to a mixer prior to being discharged to a heat exchanger. 
     
     
         9 . The system of  claim 1 , where at least one compression stage comprises an absorber containing a desiccant. 
     
     
         10 . The system of  claim 5 , where a heat transferring fluid from the heat exchanger is discharged to the regenerator; where the heat transferring fluid has received heat from the pressurized carbon dioxide. 
     
     
         11 . A method comprising:
 discharging a carbon dioxide stream into a compression system;   pressurizing the carbon dioxide stream in the compression system; where the compression system comprises:   a plurality of compression stages; where each compression stage comprises a compressor that is operative to pressurize the carbon dioxide that is dissociated from the solvent; and where at least some of the compression stages comprise a knockout tank disposed upstream of the compressor and an intercooling heat exchanger disposed downstream of the compressor; where the knockout tank is operative to remove liquid present in the carbon dioxide and where the intercooling heat exchanger is operative to remove heat generated during the pressurizing of the carbon dioxide;   removing residual liquid in the knockout tank;   cooling compressed carbon dioxide in the intercooling heat exchanger with water; and   discharging the pressurized carbon dioxide to a sequestration station.   
     
     
         12 . The method of  claim 11 , further comprising additionally cooling the compressed carbon dioxide in a heat exchanger disposed downstream of the compressor and upstream of the intercooling heat exchanger. 
     
     
         13 . The method of  claim 12 , where the additional cooling occurs in a plurality of heat exchangers each of which is disposed downstream of a compressor and upstream of an intercooling heat exchanger. 
     
     
         14 . The method of  claim 12 , where the heat exchanger is cooled with solvent that is used in a regenerator. 
     
     
         15 . The method of  claim 11 , where a heat transferring fluid used in the intercooling heat exchanger is discharged to a mixer and then discharged to a heat exchanger.