Effect of dispersion degree of iron on catalytic hydrogasification of coal char

The effect of dispersibility of Fe on coal chars with different specific surface areas on the catalytic hydrogasification performance was studied in a pressurized fixed bed reactor. The chars and catalysts were characterized by XRD, BET, H₂-TPR, FT-IR, TEM and Raman spectroscopy. The results show that the active site and graphitization degree of coal char are not the only factors affecting the catalytic gasification reaction, but the dispersion of catalyst has a greater impact on the reaction. The larger the specific surface area of coal char is, the more uniform the Fe catalyst disperses on the surface of coal char and the smaller the average grain size of the active component of catalyst is, which can promote the formation of the catalytically hydrogenated mesophase product Fe₃C and methane yield. For 900-char with higher specific surface area, the methane yield can reach 53% when the hydrogen pressure is 2 MPa, the temperature is 750℃ and the Fe loading is 5%. The effect of Fe catalyst loading on the catalytic hydrogasification was investigated with 900-char. It is found that the methane yield increases first and then decreases, and the Fe loading has a saturation point.