The main issue is the strongly exot

The main issue is the strongly exothermic process during reaction which leads to carbon particle formation on the surface of catalysts5. And the catalytic activity and stability will be significantly affected due to the increasing of temperature6. Hence, the removal of reaction heat is the key point of methanation reactor. Hanaa et al.7 pointed out that the increase of temperature can be controlled by fluidized bed reactor. Liu et al.8 found that fluidized bed reactor gave a higher CH4 production and lower bed temperature than fixed bed reactor due to the massive heat transfer coefficient. Xu et al.