No abstract

Catalytic fast pyrolysis (CFP) of beech wood chips was undertaken in a laboratory-scale fixed bed reactor equipped with a biomass semi-continuous dispenser. During pyrolysis, chars are retained on a quartz frit and the pyrolytic vapors are entrained through a fixed-bed catalyst to be converted. Several acidic catalysts such as zeolites H-Beta, zeolite HMFI and 5% Ni supported on HMFI were screened in this equipment. The Ni/HMFI catalyst was also tested in the presence of 1 vol.% of hydrogen in the feed stream. Mass and carbon balances were carefully checked and the gas, liquids and solids fractions were analyzed in-depth to evaluate the impact of the catalyst compared to thermal conversion. In the presence of a catalyst, with a low catalyst-to-biomass ratio of 0.1, a lower amount of bio-oil was formed but it contained less oxygen. The bio-oils were characterized by bidimensional GC (GCxGC) coupled with MS and FID detectors. The amount of gaseous products also increased in the presence of all catalysts. In addition of the deoxygenation, gel-permeation chromatography (GPC) showed a decrease of the highest molecular masses in the bio-oil after catalytic treatment, which confirms the conversion of some oligomers. The presence of Ni enhanced the deoxygenation reactions while the addition of H 2 is also beneficial to the bio-oil composition.