Producing Hydrogen-Rich Gases by Steam Reforming of Syngas Tar over CaO/MgO/NiO Catalysts

Abstract

The objective of this study was to develop nanosized CaO, MgO, and NiO catalysts for tar removal in biomass gasification, significantly enhancing the quality of the produced gases. Catalysts were tested in a fixed-bed reactor for biomass tar steam reforming. Toluene was chosen as a model syngas tar compound. For this purpose, pure Ca(OH)2, Mg(OH)2, and Ni(OH)2 precursors were successfully synthesized via a facile solvothermal method. Subsequent calcination of the metal hydroxide precursor at 450 °C resulted in nanosized CaO, MgO, and NiO. Different analytical techniques such as XRD, TEM, SEM, and BET were used to characterize the synthesized nanomaterials. Bulk NiO, CaO, and MgO nanomaterials and a physical mixture of CaO/MgO/NiO (equal NiO/CaO/MgO ratio) were used as catalysts for the steam gasification of toluene. Research showed higher toluene conversions, which resulted in increases in H2 yield as well as CO and CO2 selectivity. Mixed metal oxide CaO/MgO/NiO catalyst exhibited higher performance on toluene conversion, resulting in higher H2 yield and CO2 selectivity.