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 - 44 . (canceled) 
     
     
         45 . A system for cyclically removing carbon dioxide from a CO 2 -laden gas flow, selected from the group consisting of ambient air and a blended mixture of a major portion of ambient air with a minor portion of a high concentration carbon dioxide-containing effluent gases, with a CO 2  adsorbent, the system comprising:
 a chamber at one location, a plurality of conduits connected between the chamber and sources of a plurality of various fluids to be brought into and out from the chamber;   an automated system of a plurality of block valves for controlling the plurality of fluid flows passing through the plurality of conduits into and out from the chamber, the fluid flows including a flow of the CO 2 -laden gas and 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 organic amine sorbent is distributed, the amine sorbent being impregnated within the pores of the substrate and being capable of reversibly adsorbing, or binding, carbon dioxide;   the plurality of conduits comprising:   a CO 2 -laden gas flow conduit, open at one end to a CO 2 -laden gas flow source and at a second end to the chamber containing the contact structure, and 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 steam and to the chamber for directing 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 conduit for opening and closing the conduit to the flow of steam 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 ambient air to the carbon capture structure through the CO 2 -laden gas flow conduit and to pass 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 porous substrate comprises a ceramic porous monolith. 
     
     
         47 . The system of  claim 45 -wherein said CO 2 -laden gas flow conduit comprises an inlet which is designed to be connected to a blender chamber designed to blend ambient air with a minor amount of effluent gas. 
     
     
         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_substrate 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_substrate 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 steam and the system 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 designed 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 steam into the chamber. 
     
     
         52 . The system of  claim 51 , further comprising a CO 2  exit conduit for removing residual steam and the stripped CO 2  from the chamber after the capture structure has been stripped of CO 2  by the steam. 
     
     
         53 . The system of  claim 52  further comprising a CO 2  measuring detector located at the CO 2 exit conduit from the chamber to measure the CO 2  content of air in the chamber after contacting the capture structure, intended to determine when to close the automated block valve on the CO 2 -laden gas flow conduit into the chamber, and 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 open or 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 . 
     
     
         55 . The system of  claim 47 , wherein the blender chamber is designed to blend ambient air with up to 25% by volume of effluent gas, and further comprises a conduit designed to be connected to the outlet from a gas blender scrubbing process whereby the effluent gases are pre-scrubbed to remove particulates and other toxic chemicals potentially detrimental to the porous substrate.