(558c) Effect of the H2 On the CO2 Adsorption Properties of Organic-Inorganic Hybrid Amine-Based Adsorbents
Separation of CO2 from other light gases has been a subject of research focusing on natural gas purification as well as carbon capture from flue gas associated with the combustion of fossil fuels. Among several possible strategies to remove anthropogenic CO2 from flue gas, adsorption by solid sorbents has been widely studied. Current and future coal plants offer two types of CO2 separation challenges. For post-combustion CO2 capture, the separation must be made from a mixture of CO2, nitrogen, water, oxygen, sulfur oxides, and nitrogen oxides. Amine-based sorbents have been widely studied in this application. The second type of CO2 separation arises in an integrated gasification combined cycle (IGCC) power plant, whereby the fuel is gasified, shifted and then the CO2 is removed from a stream comprised mostly of hydrogen, prior to combustion of the purified hydrogen stream. Whereas post-combustion CO2 capture is normally carried out between 45¢ªC and 125¢ªC near ambient pressure, pre-combustion CO2 capture is normally carried out at more elevated temperatures and pressures. Because amine-based organic-inorganic hybrid sorbents operate near ambient conditions, all reported studies of CO2 capture with sorbents of this type have focused on post-combustion capture. Here, we report the first known study of CO2 from a hydrogen stream using amine-based organic-inorganic hybrid sorbents. A series of inorganic-organic hybrid sorbents prepared by incorporating mono-, di-, and tri-aminosilane species on porous silica substrates such as MCM-48 and SBA-15, are studied as model sorbents. The adsorption properties of these materials are characterized using a simulated mixture gas of CO2 and H2, while being compared with the results obtained from a diluted stream of pure CO2. The effect of several experimental variables, including the operating temperature, pore structure of the supports, and presence of moisture in the target gases, is also evaluated, with an overall aim of identifying and quantifying the changes of CO2 adsorption capacities and kinetics in pre-combustion vs. post-combustion applications.