Catalytic conversion of beech wood pyrolytic vapors

Alexandre Margeriat,Alissa Bouzeggane,Chantal Lorentz,Dorothée Laurenti,Nolven Guilhaume,Claude Mirodatos,Christophe Geantet,Yves Schuurman

doi:10.1016/j.jaap.2018.01.015

Alexandre Margeriat, Alissa Bouzeggane + Show 6 more

Open Access

https://doi.org/10.1016/j.jaap.2018.01.015

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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 bi-dimensional 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 H2 is also beneficial to the bio-oil composition.

Highlights

Rising energy demand requires new available energy sources that can be efficiently converted into fuels [1,2]
The catalytic reactor can be heated at a different temperature than the pyrolysis reactor and only the pyrolytic vapors are in contact with the catalyst which allow to decrease the catalyst-to-biomass ratio
Transmission electron microscopy in HAADF mode (Z contrast) reveals the presence of relatively well dispersed Ni nanoparticles in the 5%Ni/HMFI-90 catalyst (Fig. 2), but the Ni particle size distribution is broad as illustrated by the images taken at different magnifications

Summary

Introduction

Rising energy demand requires new available energy sources that can be efficiently converted into fuels [1,2]. Biomass fluidized catalytic cracking (BFCC) process was proposed with mesoporous or zeolitic catalysts [22,23,24,25] and later on industrialized by KiOR but tumbled into bankruptcy. The catalytic reactor can be heated at a different temperature than the pyrolysis reactor and only the pyrolytic vapors are in contact with the catalyst which allow to decrease the catalyst-to-biomass ratio. It has the advantage of preventing the interactions with ashes since filters can be introduced to separate these solids. This second configuration seemed to us very attractive since it allows to screen catalytic solids independently of the pyrolysis step, whereas the catalyst is never in contact with ashes, which can impair the catalyst activity

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Conclusion