The expected commercialization of coal gasification technology in the US and world-wide will create a need for advanced gas purification and separation processes capable of operating at higher temperatures and in more hostile environments than is common today. For example, a high-temperature, high-pressure process capable of separating CO{sub 2} from coal-derived gas may find application in purifying synthesis gas for H{sub 2}, NH{sub 3}, or CH{sub 3}OH production. High temperature CO{sub 2} removal has the potential for significantly improving the operating efficiency of integrated gasification-molten carbonate fuel cells for electric power generation. This study proved the technical feasibility of a CO{sub 2}-separation process based upon the regenerable noncatalytic gas-solid reaction between CaO and CO{sub 2} to form CaCO{sub 3}. Such a process operating at 650{degree}C and 15 atm with 15% CO{sub 2}, in the feed gas has the potential for removing in excess of 99% of the CO{sub 2} fed. Selection of a sorbent precursor which, upon calcination, produces high-porosity CaO is important for achieving rapid and complete reaction. The addition of magnesium to the sorbent appears to improve the multicycle durability at a cost of reduced CO{sub 2} capacity per unit mass of sorbent. When CO and H{sub 2}O were present in the feed gas, the water gas shift and carbonation reactions occurred simultaneously, thus providing a potential alternate route for the production of H{sub 2} from coal-derived gas. Material and energy balances based on an Aspen simulation were conducted by METC personnel. This phase of the study identified process related problems which must be addressed before the combined shift-carbonation process could become commercial. Other applications of the combined shift-carbonation process, in addition to the production of high purity H{sub 2}, have been suggested.