Ex-situ catalytic fast pyrolysis of Beetle-killed lodgepole pine in a novel ablative reactor

Abstract Biomass fast pyrolysis involving the rapid thermal degradation of organic materials in the absence of oxygen is one of the most promising process for the sustainable production of alternative liquid fuels. However, it typically requires a relatively small particle size of dry biomass and the products need to be upgraded due to their high oxygen content. In this work, we employed a novel ablative fast pyrolysis reactor to convert as-received chips of Beetle killed lodgepole pine into vapors, and subsequently turned the vapors into aromatic hydrocarbons by ex-situ catalytic upgrade in a one pot synthesis system. We used pelletized HZSM-5 zeolite in a packed bed for the upgrade reaction and thoroughly characterized both fresh and spent catalysts by nitrogen sorption and electron microscopy. Our results revealed that a catalyst-to-biomass ratio of 4:1 and an upgrade temperature of 550 °C produced the lowest yield of coke (9.4 wt%) and the highest yield of aromatic hydrocarbons (3.5 wt%) with very high selectivity (94%) to benzene, toluene and xylene (BTX). We also analyzed the non-condensable gases to elucidate the deoxygenation mechanisms. This ablative reactor could be converted into a portable unit to produce alternative fuels without the need for biomass pre-treatment (i.e. grinding and drying) and transportation, creating a more sustainable and economically viable process for generating alternative fuels and specialty chemicals.