Steam reforming of tar compounds over Ni/olivine catalysts doped with CeO2

Abstract

Biomass gasification is gaining attention as a route for biomass energy production. Producer gas from this process usually contains unacceptable levels of tar. Tar can cause operational problems in downstream processes by blocking gas coolers, filter elements and engine suction channels. Most producer gas applications require removal of at least part of the dust and tar before the gas can be used. In this study, olivine was used as a substrate for various catalyst formulations designed to steam reform tar to gas. Three catalysts were prepared by wet impregnation, yielding the following compositions: 3.0% NiO/olivine, 3.0% NiO/olivine doped with 1.0% CeO2 and 6.0% NiO/olivine. Benzene and toluene were selected as model compounds of biomass tar. Catalytic steam reforming of these compounds was performed in a bench scale fixed bed reactor at temperatures between 700 and 830 C using a molar ratio of steam/carbon (S/ C) equal to 5. The effect of catalyst composition on tar conversion and yields of various product gases were determined. Coking tendencies of the catalysts were determined, and characterization by XRD and SEM was performed. 3.0% NiO/olivine doped with 1.0% CeO2 was the most promising catalyst based on catalytic activity and its resistance to coking. 2006 Elsevier Ltd. All rights reserved.