System and Method for Carbon Dioxide Capture and Sequestration

Abstract

A method for removing carbon dioxide directly from ambient air, using a sorbent under ambient conditions, to obtain relatively pure CO2. The CO2 is removed from the sorbent using process heat, preferably in the form of steam, at a temperature in the range of not greater than about 130° C., to capture the relatively pure CO2 and to regenerate the sorbent for repeated use. Increased efficiency can be achieved by admixing with the ambient air, prior to contacting the sorbent, a minor amount of a preferably pretreated effluent gas containing a higher concentration of carbon dioxide. The captured carbon dioxide can be stored for further use, or sequestered permanently. The above method provides purified carbon dioxide for further use in agriculture and chemical processes, or for permanent sequestration.

1 - 36 . (canceled) 
     
     
         37 . A system for cyclically removing carbon dioxide from a CO 2 -laden gas flow selected from ambient air or a blended mixture of a minor portion of carbon dioxide-containing effluent gases with a major portion of carbon dioxide laden ambient air, by adsorbing or binding the CO 2  on a sorbent for CO 2 , and capturing the CO 2  by stripping the CO 2  from the sorbent, the system comprising:
 a contact structure comprising a porous substrate with a surface area along which an amine sorbent is distributed that is capable of reversibly adsorbing, or binding to, carbon dioxide, an air conduit, open at one end to the ambient atmosphere and at a second end to a blending zone, an effluent gas conduit having an inlet and an outlet, the blending zone being also connected to the outlet from the effluent gas conduit, the inlet to the effluent gas conduit being connected to a source of effluent gases, the outlet from the blending zone emptying into the contact structure, the relative flow of effluent gases and ambient air into the blending zone being such as to result in a gas blend comprising not greater than 25% by volume of effluent gases and a blended temperature of not greater than 25° C. after blending;   the capture structure being movable between a first location where it receives the blended flow of carbon dioxide-laden ambient air and effluent gases, and a second location;   a sealable regeneration chamber located at the second location and capable of sealingly containing the capture structure;   a source of process heat steam for providing steam at a temperature of not greater than about 130° C.;   a hot fluid conduit connected to the source of process heat steam and to the sealable regeneration chamber for directing such process heat steam at the carbon dioxide-loaded sorbent on the capture structure in the regeneration chamber to strip carbon dioxide from the sorbent; and   a fluid conduit for carrying the stripped carbon dioxide away from the regeneration chamber.   
     
     
         38 . The system of  claim 37 , wherein said substrate comprises a porous monolith. 
     
     
         39 . The system of  claim 37 , wherein said effluent gas conduit is connected to the outlet from a gas scrubbing process whereby the effluent gases are pre-scrubbed to remove particulates and other toxic chemicals potentially detrimental to the porous substrate. 
     
     
         40 . The system of  claim 37 , wherein said steam is provided at a temperature of not greater than 100-120° C. 
     
     
         41 . The system of  claim 37  wherein the porous solid mass comprises a bed of highly porous silica particles, where each particle supports on their surfaces the sorbent. 
     
     
         42 . The system of  claim 37 , wherein the porous solid mass is in the form of a vertically oriented carbon capture structure, and further comprising a carriage for alternately moving the vertically oriented carbon capture structure between the capture chamber and the release chamber. 
     
     
         43 . The system of  claim 37 , wherein the hot fluid conduit carries saturated steam and further comprising exhaust means for removing residual air from the capture structure and the regeneration chamber after the capture structure is sealed into the regeneration chamber and before introducing the saturated steam into the regeneration chamber. 
     
     
         44 . The system of  claim 43 , wherein the hot fluid conduit carries saturated steam and further comprising exhaust means for removing residual steam and the stripped CO 2  from the capture structure and the regeneration chamber after the capture structure has been stripped of CO 2  by the saturated steam. 
     
     
         45 . A system for cyclically removing carbon dioxide from a CO 2 -laden gas flow selected from ambient air or a blended mixture of a minor portion of carbon dioxide-containing effluent gases with a major portion of carbon dioxide laden ambient air with a CO 2  adsorbent, the system comprising:
 a chamber at one location, including an automated system of block valves controlling various fluid flows, the fluid flows including a flow of the CO 2 -laden gas, a flow of process heat steam, and a flow of stripped CO 2 ;   a carbon dioxide contact structure within the chamber, the contact structure comprising a porous substrate with a surface area along which an amine sorbent is distributed, the amine sorbent being capable of reversibly adsorbing, or binding, carbon dioxide;   a CO 2 -laden gas flow conduit, open at one end to the CO 2 -laden gas flow and at a second end to the chamber containing the contact structure;   an automated block valve on the CO 2 -laden gas flow conduit for opening and closing the conduit to the CO 2 -laden gas flow into the chamber;   a hot fluid conduit for providing steam at a temperature of up to about 130° C. designed to be connected to a source of process heat steam and to the chamber for directing process heat steam at the carbon dioxide-loaded sorbent on the capture structure in the chamber to strip carbon dioxide from the sorbent;   an automated block valve on the hot fluid flow conduit for opening and closing the conduit to the hot fluid flow into the chamber;   a CO 2  conduit for carrying stripped carbon dioxide away from the chamber; and   an automated block valve on the CO 2  conduit for opening and closing the conduit to the flow out of the chamber of the stripped CO 2 ;   whereby the automated block valve system is designed and adapted to alternatively and successively pass carbon dioxide laden air to the carbon capture structure through the CO 2 -laden gas flow conduit and to pass process heat steam to the carbon capture structure, through the hot fluid conduit, to separate the carbon dioxide from the sorbent and regenerate the sorbent, and to allow the capture of the stripped CO 2  from the chamber.   
     
     
         46 . The system of  claim 45 , wherein said substrate comprises a porous monolith. 
     
     
         47 . The system of  claim 45 , wherein said effluent gas conduit is designed to be connected to the outlet from a gas scrubbing process whereby the effluent gases are pre-scrubbed to remove particulates and other toxic chemicals potentially detrimental to the porous substrate. 
     
     
         48 . The system of  claim 45 , wherein said steam is provided at a temperature of not greater than about 100-120° C. 
     
     
         49 . The system of  claim 45  wherein the porous solid mass comprises a bed of highly porous silica particles, where each particle supports on their surfaces the sorbent. 
     
     
         50 . The system of  claim 45 , wherein the porous solid mass is in the form of a vertically oriented carbon capture structure. 
     
     
         51 . The system of  claim 45 , wherein the hot fluid conduit is designed to carry saturated steam and further comprising an air exhaust conduit, an automated block valve on the exhaust conduit for opening and closing the conduit to the air exhaust conduit from the chamber and a pressure reducing means for removing residual air through the air exhaust conduit from the capture structure and the chamber after the CO 2 -laden gas flow is terminated and before opening the block valve in the hot fluid conduit to allow the saturated steam into the chamber. 
     
     
         52 . The system of  claim 51 , further comprising exhaust means for removing residual steam and the stripped CO 2  from the capture structure and the chamber after the capture structure has been stripped of CO 2  by the saturated steam. 
     
     
         53 . The system of  claim 52  further comprising a CO 2  measuring detector located, at the exit from the chamber to measure the CO 2  content of air after contacting the capture structure, so as to determine when to close the automated block valve on the CO 2 -laden gas flow conduit into the chamber, and a CO 2  measuring detector located at the exit from the regeneration chamber to determine when to open or close the automated block valve on the hot fluid flow conduit for starting and halting the flow of steam into the chamber and to close the automated block valve on the CO 2  conduit for opening and closing the conduit to the flow out of the chamber of the stripped CO 2 . 
     
     
         54 . The system of  claim 42  comprising a pair of vertically oriented carbon capture structures wherein the carriage moves each such vertically oriented carbon capture structure alternately and successively to the removal chamber and to the regeneration chamber while the other of the pair of vertically oriented carbon capture structures is being moved in the opposite direction, such that when one such vertically oriented carbon capture structure is being heated with process heat to separate the previously adsorbed carbon dioxide from the sorbent and regenerate the sorbent on the porous support, the other is in the removal chamber adsorbing CO 2  from the air.