Non-Catalytic And Catalytic Fast Pyrolysis Of Lignocellulosic Biomass Into Bio-Oil Over Aluminosilicate-Based Catalysts
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Date
2018-11-01
Authors
Tan, Yee Ling
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
Depletion of fossil resources and increasing motivation to develop renewable
liquid fuels and chemicals have generated interest in the study of biomass conversion.
This study aims to study the product yield and quality obtained from thermal and
catalytic fast pyrolysis of durian shell, rattan and karanj shell in two-stage fixed-bed
reactor over silica-alumina catalyst with different silica/alumina ratios, calcium- or
iron-modified silica-alumina, and industrial waste-derived aluminosilicate catalysts.
Effects of particle size (up to 5 mm) and pyrolysis temperature (250-650 'C) were
investigated in thermal fast pyrolysis while the effects of catalytic temperature,
catalyst/feedstock ratio, types of feedstock, and catalyst regeneration were
determined in catalytic fast pyrolysis. The best temperature for liquid production for
durian shell, rattan and karanj shell was 650 'C, 550 'C and 550 'C, respectively.
Silica-alumina catalyst with microporous characteristic was synthesized using co-precipitation method. The bio-oil produced from durian shell over silica-alumina
catalyst with silica/alumina ratio of 5.1 (SA-5.1) at 600 'C has deoxygenation degree of 93.61% with 75.45% aromatics content. The addition of calcium reduced coke
deposition on SA-5.1 while iron promoted the yield of aromatics and hydrocarbons.
Electric-arc-furnace-slag-derived catalyst (AS-EAF) produced 50.21 wt% bio-oil
with deoxygenation degree of 85.49% and 72.82% hydrocarbons content at 500 'C. SA-5.1 promoted the formation of esters in catalytic fast pyrolysis of rattan and the
formation of aromatics and hydrocarbons in catalytic fast pyrolysis of karanj shell.
AS-EAF promoted the yield of esters and hydrocarbon in bio-oil produced from
rattan, and the yield of aromatics in bio-oil produced from karanj shell. The coke
deposited on SA-5.1 and AS-EAF in catalytic fast pyrolysis of durian shell is 12.68
wt% and 1.95 wt%, respectively. SA-5.1 has better performance after regeneration in
catalytic fast pyrolysis of karanj shell at 500 'C, which the deoyxgenation degree
increased from 35.15% to 57.13% and the coke deposition decreased from 15.71 wt%
to 11.42 wt%. Although deoxygenation degree of bio-oil produced from karanj shell
over AS-EAF reduced after five cycles, the coke deposition was 3.91 wt% after used,
which is lower than that of SA-5.1. The kinetic parameters were calculated using
Coats-Redfern method. The reaction models of thermal and catalytic pyrolysis of
durian shell in Phase II are accounted for one-way diffusion model while the Phase
III of thermal and catalytic pyrolysis follows second or third-order reaction models.
Catalytic pyrolysis with SA-5.1 exhibited lower activation energy of 115.55 kJ/mol
than thermal pyrolysis with activation energy of 170.84 kJ/mol in Phase III, indicates
SA-5.1 promoted lignin decomposition.