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Microexplosions in the Upgrading of Biomass-Derived Pyrolysis Oils and the Effects of Simple Fuel Processing
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posted on 2016-02-19, 20:20 authored by Andrew
R. Teixeira, Richard J. Hermann, Jacob S. Kruger, Wieslaw J. Suszynski, Lanny D. Schmidt, David P. Schmidt, Paul J. DauenhauerThe development of biofuels produced from biomass-derived
pyrolysis
oils (bio-oil) requires a deeper understanding of the bio-oil vaporization
required for catalytic hydrodeoxygenation, reforming and combustion
processes. Through the use of high-speed photography, bio-oil droplets
on a 500 °C alumina disk in nitrogen gas were observed to undergo
violent microexplosions capable of rapidly dispersing the fuel. High
speed photography of the entire droplet lifetime was used to determine
explosion times, frequency and evaporation rates of the bio-oil samples
that have been preprocessed by filtering or addition of methanol.
Filtration of the oil prior to evaporation significantly reduced the
fraction of droplets that explode from 50% to below 5%. Addition of
methanol to bio-oil led to uniform vaporization while also increasing
the fraction of droplets that exploded. Experiments support the necessity
of dissolvable solids for the formation of a volatile core and heavy
shell which ruptures and rapidly expands to produce a violent bio-oil
microexplosion.