Using a manganese ore as catalyst for upgrading biomass derived gas

Secondary catalytic tar cleaning has been evidenced as a promising technology for upgrading gas derived from biomass gasification. When applying this technology downstream a biomass gasifier, the tar fraction in the raw gas can be reduced and the content of hydrogen can be increased. In this work, experiments have been conducted in a Chemical-Looping-Reforming (CLR) reactor. The present reactor system features a circulating fluidized bed as the reformer section, which offers a higher gas-solids contact time than a bubbling bed configuration previously tested. All experiments were performed using raw gas from the Chalmers 2-4 MWth biomass gasifier as feedstock to the reactor system. The catalyst inventory consisted of a natural manganese ore and its activity was evaluated at three different temperature levels - 800oC, 850oC and 880oC - and with an oxygen content of 2.2%, corresponding to a theoretical air-to-fuel ratio of 0.06. Experimental results showed that the manganese ore exhibits catalytic activity with respect to tar conversion and a tar reduction of as much as 72% was achieved at 880oC. Moreover, this material showed high activity towards hydrogen production