TITLE:
Hydrothermal Liquefaction of Water Hyacinth: Effect of Process Conditions and Magnetite Nanoparticles on Biocrude Yield and Composition
AUTHORS:
Dan Egesa, Patrick Mulindwa, Edward Mubiru, Hilda Dinah Kyomuhimbo, Godwin Aturagaba
KEYWORDS:
Hydrothermal Liquefaction, Water Hyacinth, Magnetite Nanoparticles, Biocrude Oil
JOURNAL NAME:
Journal of Sustainable Bioenergy Systems,
Vol.11 No.4,
October
15,
2021
ABSTRACT: In this work, an efficient way of converting the
water hyacinth to biocrude oil using
magnetite nanoparticles (MNPs) as potential catalysts was demonstrated
for the first time. MNPs were synthesised by co-precipitation and used in the
hydrothermal liquefaction (HTL) of water hyacinth at different reaction conditions
(temperature, reaction time, MNPs to biomass ratio and biomass to water ratio).
The best reaction conditions were as follows: temperature— 320, reaction time—60 minutes, MNPs to biomass ratio – 0.2 g/g and
biomass to water ratio – 0.06 g/g. HTL in
presence of MNPs gave higher biocrude yields compared to HTL in absence
of MNPs. The highest biocrude yield was 58.3 wt% compared to 52.3 wt% in
absence of MNPs at similar reaction conditions. The composition of biocrude oil
was analysed using GC-MS and elemental analysis. GC-MS results revealed that
HTL in presence of MNPs led to an increase in the percentage area corresponding
to hydrocarbons and a reduction in the percentage area corresponding to oxygenated
compounds, nitrogenated compounds and sulphur compounds. Elemental analysis
revealed an increase in the hydrogen and carbon content and a reduction in the
nitrogen, oxygen and sulphur content of the biocrude when HTL was done in
presence of MNPs compared to HTL in absence of MNPs. The nanoparticles were
recovered from the biochar by sonication and magnetic separation and recycled.
The recycled MNPs were still efficient as HTL catalysts and were recycled five times. The application of MNPs in the HTL of
water hyacinth increases the yield of biocrude oil, improves the quality of
biocrude through removal of hetero atoms, oxygen and sulphur compounds and is a
potentially economical alternative to the traditional petroleum catalysts since
MNPs are cheaper, widely available and can be easily recovered magnetically and
recycled. This will potentially lead to an economical, environmentally friendly
and sustainable way of producing biofuels from biomass.