Carbon Deposition on Nickel-based Catalyst during Bio-syngas Methanation in a Fluidized Bed Reactor

Abstract

Carbon deposition on the nickel-based catalyst is a common phenomenon during the bio-syngas methanation process. A nickel-based catalyst supported on y-AkO3 was prepared with impregnation method. Carbon deposition tests were carried out in a fluidized bed reactor to explore the carbon deposition phenomenon and the spent catalysts were collected for TG and gas sorption analysis. The TG analysis showed that the weight of the deposited carbon occupied about 1.90wt% of the total spent catalyst. The nitrogen sorption analysis presented that the BET surface area of the spent catalyst was much less than that of the raw catalyst and pore volume and width were also less than those of the raw catalyst. This is because during the methanation process, some kinds of stable carbon are formed besides active carbon and they accumulate on the catalyst surface, which can cause the encapsulation of the active site and block the tiny porous channels on the catalyst surface. All of these may explain the textural properties changes between raw catalyst and spent catalyst. These findings also help to furtherly improve and design the highly carbon-resistant catalysts.