Removal of tar from biomass gasification process by steam reforming over nickel catalysts

Abstract

Tar is a major problem in a biomass gasification process, causing blocking, fouling, corrosion, erosion and abrasion of process equipments. Tar steam reforming is a very attractive technique for tar removal. It converts high molecular weight hydrocarbons of tar into smaller gas products including H₂, CH₄, CO and CO₂. Preliminary research focuses on simulation of tar steam reforming. It was assumed to be at thermodynamic equilibrium and the calculations were performed using Aspen plus. The simulation results help understand the effect of operating condition and identify suitable operating conditions (reaction temperature, S/C ratio) for the experimental tar steam reforming. Representative tar consisted of toluene, naphthalene, phenol and pyrene whose compositions varied with temperatures of biomass gasification (700-900℃). The experimental study of the tar steam reforming reaction were carried out at different temperatures (450-650 ๐C), S/C ratios (1-5), type of supports (Al₂O₃, CaO, MgO) and %metal loading of a nickel catalyst. The experimental results follow the trends observed from the simulations that the reaction at high temperature and S/C ratio produce more hydrogen content. 20%Ni/Al₂O₃ was reported as a suitable catalyst which offered stable and efficiency activity for tar steam reforming.