A pressure–temperature swing process for the methanation of carbon oxides using fluorinated hydriding alloys

Abstract A catalytic reaction process called the Pressure–Temperature Swing Process (P–T Swing Process) was developed in this laboratory for recovering carbon oxides by using fluorinated hydriding alloys. The process is based on the extreme reactivity of the monatomic hydrogen stored in the crystalline structure of the fluorinated metal hydride which exhibits high affinity with hydrogen and a strong resistance against impurities. The hydrogenation of carbon oxides takes place near the surface of the fluoride layer and produces methane and water while molecular hydrogen leaves the fluoride layer to the gas phase as the temperature and pressure is increased. The aim of this paper is to demonstrate the validity of the proposed process through experimental studies on 1000 ppm, 5% and 8% CO 2 -containing H 2 gas mixtures during temperature switching between 2 isothermal conditions at 30 °C and 150 °C. The adsorbed CO 2 is found to be converted easily to CH 4 and water by the P–T swing process. The roles of the fluoride layer during hydriding and dehydriding reactions are as yet unknown and should be subjected to further detailed studies.