Comparative study of fluidized-bed and fixed-bed reactor for syngas methanation over Ni-W/TiO2-SiO2 catalyst

In this work, syngas methanation over Ni-W/TiO2-SiO2 catalyst was studied in a fluidized-bed reactor (FBR) and its performance was compared with a fixed-bed reactor (FIXBR). The effects of main operating variables including feedstock gases space velocity, coke content, bed temperature and sulfur-tolerant stability of 100 h life were investigated. The structure of the catalysts was characterized by XRD, N-2 adsorption-desorption and TEM. It is found that under same space velocity from 5000 h(-1) to 25000 h(-1) FBR gave a higher CH4 yield, lower coke content, and lower bed temperature than those obtained in FIXBR. Ni-W/TiO2-SiO2 catalyst possessed excellent sulfur-tolerant stability on the feedstock gases less than 500 ppm H2S in FBR. The carbon deposits formed on the spent catalyst were in the form of carbon fibers in FBR, while in the form of dense accumulation distribution appearance in FIXBR.