Resistance to sulfur poisoning of hot gas cleaning catalysts for the removal of tar from the pyrolysis of cedar wood

In the partial oxidation of tar derived from the pyrolysis of cedar wood, the effect of H2S addition was investigated over non-catalyst, steam reforming Ni catalyst, and Rh/CeO2/SiO2 using a fluidized bed reactor. In the non-catalytic gasification, the product distribution was not influenced by the presence of H2S. Steam reforming Ni catalyst was effective for the tar removal without H2S addition, however, the addition of H2S deactivated drastically. In contrast, Rh/CeO2/SiO2 exhibited higher and more stable activity than the Ni catalyst even under the presence of high concentration of H2S (280 ppm). On the Ni catalyst, the adsorption of sulfur was observed by XPS and Ni species was oxidized during the partial oxidation of tar. In the case of Rh/CeO2/SiO2, the adsorption of sulfur was below the detection limit of XPS. This can be related to the self-cleaning of catalyst surface during the circulation in the fluidized bed reactor for the partial oxidation of tar derived from cedar pyrolysis.