Catalytic Gasification Of Biomass For Hydrogen In External Circulating Radial Flow Moving Bed Reactor System

In this thesis, a novel process of catalytic gasification of biomass for hydrogen-rich gas with solid heat carrier is proposed, which is mainly based on the external circulating radial flow moving bed (ECRMB) reactor and catalytic hot gas cleaning.Biomass gasification experiments were carried out in a lab-scale ECRMB biomass gasification facility. The effects of reaction conditions, including gasification temperature and steam/biomass mass ratio (S/B), system stability, and catalyst regenerability were investigated using Nickel-based, Ferrum-based, and AER (Absorption Enhanced Reforming) catalysts as bed material. The results show that gasification temperature and S/B are important factors for the gasification process. In the ECCMB biomass gasification system, the Nickel-based catalyst shows a high activity for tar decomposition and methane reforming. The tar content of0.13g/Nm3and methane content of less than0.6vol.%can be obtained at the gasification temperature of650℃and S/B=1.2with Nickel-based catalyst. As for the Ferrum-based catalyst, it presents a lower activity for methane reforming, and its activity for tar decomposition is higher than calcined olivine but lower than Nickel-based catalyst. Using AER catalyst as bed material, an effective AER result can be formed which improves the yield of H2and the conversion of water, while at the same time, decreases the yield of tar and CO2. According to the characteristic of each catalyst, a coupling utility was carried out in the process of biomass gasfication. The hydrogen-rich gas with low CO2and tar content was obtained at the low reaction temperature, and the content of H2was higher than80vol.%.The results verified that this new concept of biomass gasification for hydrogen-rich gas is feasible. The combination of ECRMB gasification system with effective catalyst is a good solution to enhance the efficiency of the process and decrease the tar yield.