Tar In-situ Conversion for Biomass Gasification via Mixing-simulation with Rice Husk Char-supported Catalysts

Abstract

This paper initially proposed a catalytic pyrolysis technology for tar conversion using the rice husk char (RHC) and rice husk ash (RHA) supported nickel-iron catalyst during biomass pyrolysis/gasification. Biomass tar could be in-situ transformed effectively in the gasifer by co-pyrolysis with the RHC/RHA supported catalysts at 800 oC, simplifying the follow-up tar elimination process. Under the optimized conditions, the tar conversion efficiency can reach about 92.3% using the Ni-Fe char (namely RHC Ni-Fe, without calcination), which exhibited more advantages of convenient and energy-saving. Significantly, the partial metal oxides (e.g., NiO) in char matrix could be in-situ deoxidized by reducing gases (e.g., H2, CO) or carbon atoms into the metallic status (e.g., Ni0), enhancing the catalytic performance of tar conversion. In addition, mixing with other solid particles (e.g., sand, RHC/RHA supported catalysts) can improve biomass (e.g., RH) fluidization behavior by optimizing the operation parameters (e.g., particle size, mass fraction) in the mode of fluidized bed gasifier (FBG). After the solid-solid mixing simulation, the RH mass fraction of 0.5 and the particle diameter of 0.5mm can be employed in the binary mixture of RH and RHC/RHA.