Deactivation and Burning Regeneration of Coked Acid Catalysts in Catalytic Cracking Process of Biomass Tar

In order to study the activity regeneration of deactivating acid catalysts with carbon deposition, the catalytic cracking experiments on biomass tar were carried out in a fixed bed reactor with high-alumina brick as acid catalyst. The results show that the catalyst activity declines with the increase of reaction time, due to the carbon depositing on catalyst surface. The carbon depositing rate on catalyst surface becomes smooth after a period of work time, and the mode of coke deposition becomes multi-layer form monolayer. The quantities of the carbon depositing on the catalyst surface will be stable, when the coking rate is equal to the rate of coke consumption. The regeneration method of coke burning can effectively recover the activity of catalyst. But the activity of regenerated catalyst cannot be the same as that of fresh catalyst, because the acidic structure and active center on catalyst surface are destroyed in coke combustion process. In addition, the sintering or crystallization phenomenon will occur in catalysts regeneration process with coke burning, which may change the physical characteristics of catalyst, such as porosity, pore size distribution, specific surface area, and so on.