Systems and methods for treating carbon dioxide

Abstract

A heat exchange assembly for treating carbon dioxide (CO 2 ) is described. The heat exchange assembly includes a housing that includes an inlet, an outlet, and an inner surface that defines a cavity extending between the inlet and the outlet. The housing is configured to receive solid CO 2 through the inlet. At least one heat exchange tube extends through the housing. The heat exchange tube is oriented to contact solid CO 2 to facilitate transferring heat from solid CO 2 to a heat exchanger fluid being channeled through the heat exchange tube to facilitate converting at least a portion of solid CO 2 into liquid CO 2 . The heat exchange assembly is configured to recover a refrigeration value from the solid CO 2 and transfer at least a portion of the recovered refrigeration value to a flue gas.

What is claimed is: 
     
         1 . A heat exchange assembly for treating carbon dioxide (CO 2 ), said heat exchange assembly comprising:
 a housing comprising an inlet, an outlet, and an inner surface that defines a cavity extending between said inlet and said outlet, said housing configured to receive solid CO 2  through said inlet; and   at least one heat exchange tube extending through said housing, said heat exchange tube oriented to contact solid CO 2  to facilitate transferring heat from solid CO 2  to a heat exchange fluid being channeled through said heat exchange tube to facilitate converting at least a portion of solid CO 2  into liquid CO 2 , said heat exchange assembly configured to recover a refrigeration value from the solid CO 2  and transfer at least a portion of the recovered refrigeration value to a flue gas.   
     
     
         2 . A heat exchange assembly in accordance with  claim 1 , wherein said housing is configured to maintain said cavity within a predefined range of pressures to prevent re-sublimation of solid CO 2  to gaseous CO 2 . 
     
     
         3 . A heat exchange assembly in accordance with  claim 1 , wherein said housing inner surface extends between an upper portion and a lower portion extending below said upper portion, said lower portion configured to contain liquid CO 2  therein. 
     
     
         4 . A heat exchange assembly in accordance with  claim 3 , wherein said at least one tube includes an outer surface and a plurality of fins extending outwardly from said tube outer surface, each fin of said plurality of fins is oriented to support solid CO 2  within said upper portion. 
     
     
         5 . A heat exchange assembly in accordance with  claim 4 , wherein each fin of said plurality of fins is at least partially submerged within liquid CO 2 . 
     
     
         6 . A heat exchange assembly in accordance with  claim 4 , wherein adjacent fins are oriented such that a plurality of openings are defined between adjacent fins, each opening is sized to channel liquid CO 2  from said upper portion to said lower portion. 
     
     
         7 . A heat exchange assembly in accordance with  claim 1 , further comprising a lockhopper assembly coupled to said housing inlet for channeling solid CO 2  into said housing cavity through said inlet. 
     
     
         8 . A heat exchange assembly in accordance with  claim 7 , wherein said lockhopper assembly is configured to enable solid CO 2  to be gravity fed into said housing cavity. 
     
     
         9 . A gas treatment system for use in treating carbon dioxide (CO 2 ) in a flue gas, said gas treatment system comprising:
 a cooling system coupled to a source of flue gas and configured to receive a flow of flue gas from the source, said cooling system configured to cool CO 2  within the flue gas to form solid CO 2 ; and   a heat exchange assembly coupled to said cooling system for receiving a flow of solid CO 2  from said cooling system, wherein said heat exchange assembly is configured to recover a refrigeration value from the solid CO 2  and transfer at least a portion of the recovered refrigeration value to the flue gas, said heat exchange assembly comprising:
 a housing comprising an inlet, an outlet, and an inner surface that defines a cavity extending between said inlet and said outlet, said housing configured to receive solid CO 2  through said inlet; and 
 at least one heat exchange tube extending through said housing, said heat exchange tube oriented to contact solid CO 2  to facilitate transferring of heat from solid CO 2  to a heat exchange fluid being channeled through said heat exchange tube to facilitate converting at least a portion of solid CO 2  into liquid CO 2 . 
   
     
     
         10 . A gas treatment system in accordance with  claim 9 , wherein said housing is configured to maintain said cavity within a predefined range of pressures to prevent re-sublimation of solid CO 2  to gaseous CO 2 . 
     
     
         11 . A gas treatment system in accordance with  claim 9 , wherein said housing inner surface extends between an upper portion and a lower portion extending below said upper portion, said lower portion configured to contain liquid CO 2  therein. 
     
     
         12 . A gas treatment system in accordance with  claim 11 , wherein said at least one tube includes an outer surface and a plurality of fins extending outwardly from said tube outer surface, each fin of said plurality of fins is configured to support solid CO 2  within said upper portion. 
     
     
         13 . A gas treatment system in accordance with  claim 12 , wherein each fin of said plurality of fins is at least partially submerged within liquid CO 2 . 
     
     
         14 . A gas treatment system in accordance with  claim 12 , wherein adjacent fins are oriented such that a plurality of openings are defined between adjacent fins, each opening is sized to channel liquid CO 2  from said upper portion to said lower portion. 
     
     
         15 . A gas treatment system in accordance with  claim 9 , further comprising a lockhopper assembly coupled between said cooling system and said heat exchange assembly for receiving solid CO 2  from said cooling system, said lockhopper assembly configured to enable solid CO 2  to be gravity fed into said housing cavity. 
     
     
         16 . A gas treatment system in accordance with  claim 9 , further comprising a CO 2  sequestration system coupled to said heat exchange assembly for receiving a flow of liquid CO 2  from said heat exchange assembly. 
     
     
         17 . A method of treating carbon dioxide (CO 2 ), said method comprising:
 channeling a flue gas containing CO 2  to a cooling system to cool the flue gas to form solid CO 2 ;   channeling the solid CO 2  to a heat exchange assembly, wherein the heat exchange assembly includes a housing configured to receive solid CO 2  therein, and at least one heat exchange tube extending through the housing;   adjusting a pressure within the housing to maintain the housing pressure within a predefined range of pressures to prevent re-sublimation of solid CO 2 ;   channeling a flow of heat exchange fluid through the at least one heat exchange tube to facilitate a transfer of heat from solid CO 2  to the heat exchange fluid to convert at least a portion of solid CO 2  into liquid CO 2  and to recover a refrigeration value from the CO 2 ; and   transferring at least a portion of the recovered refrigeration value to the flue gas to facilitate cooling the flue gas.   
     
     
         18 . A method in accordance with  claim 17 , further comprising channeling the heat exchange fluid to a pre-cooling system to facilitate transferring the recovered refrigeration value to the flue gas to facilitate cooling the flue gas. 
     
     
         19 . A method in accordance with  claim 17 , further comprising channeling solid CO 2  from a lockhopper assembly to the heat exchange assembly, wherein the lockhopper assembly is configured to enable solid CO 2  to be gravity fed into the housing cavity. 
     
     
         20 . A method in accordance with  claim 17 , further comprising channeling liquid CO 2  from the heat exchange assembly to a CO 2  sequestration system.