In situ performance of various metal doped catalysts in micro-pyrolysis and continuous fast pyrolysis

Abstract

Catalytic fast pyrolysis (CFP) of biomass is a promising route for the production of deoxygenated liquids suitable for further conversion to fuels and/or chemicals. In this work, CFP of pine wood in a micro-pyrolysis setup and a continuously operated bench-scale fast pyrolysis unit was performed to investigate the effect of catalyst type and reactor type on the products. In total, eight zeolite catalysts (metal doped acidic, basic, and γ-alumina catalysts and their parent counterparts) were tested. In the bench-scale unit, the distribution of products including liquid organics (i.e. CFP-oil), water, char, coke, and non-condensable gases (NCGs) were measured, as well as the compositions of the CFP-oil and NCGs. CFP gives rise to the production of additional water, coke, and NCGs at the expense of CFP-oil. However, the quality of the obtained CFP-oil was altered significantly depending on the catalyst type. For all catalysts, the acidity of CFP-oils remarkably decreased with an increased deoxygenation. The best performance was obtained with the lower redox-metal containing acidic catalyst and freshly calcined metal doped basic mixed-metal oxide catalysts. Py-GC/MS results obtained with the same catalysts were found to be only partially indicative for the performance of a catalyst in CFP of biomass.