Catalytic fast pyrolysis of biomass over microporous and hierarchical zeolites: characterization of heavy products

The conversion of lignocellulosic biomass by catalytic fast pyrolysis (CFP) is a promising route to produce green aromatics and sustainable biofuels. The zeolite catalysts present a high ability to produce light aromatics but also heavy products. In this work, these heavy products are monitor by a well-established petroleomic approach.. The selectivity towards the heavy bio-oil components of both a common HZSM-5 zeolite and a hierarchical zeolite was investigated. Part of molecular species from lignin derivatives is still present in the upgraded bio-oils. Deoxygenation and aromatization are the main modifications of the heavy compounds caused by zeolites especially for the sugaric derivatives. These effects are stronger for the hierarchical zeolite for which numerous heavy hydrocarbons (not oxygenated) are generated due to enhanced mass transfers within the crystallites. Moreover, this catalyst demonstrates a better stability upon an increase in the biomass-to-catalyst ratio.