In this study, two packed bed hydrotreating
reactors are modelled with
the purpose of estimating the kinetic
parameters of deoxygenation and denitrogenation
for a two-stage upgrading
of biocrude produced from hydrothermal
liquefaction (HTL). In order to
simplify the many reactions happening
during the process, the oxygen
and nitrogen are lumped into a single
compound each (O,N), whose concentration
is equal to the concentration
of O,N in the biocrude. Although
the model showed good results up to
370oC, more severe conditions showed
considerable errors for the N concentration.
So, an optimization was performed,
where the nitrogen was divided
in two compounds, as "high"
and "low" reactivity. Moreover, the
study commenced with experimental
work on hydrotreating of HTL miscanthus
biocrude, under different temperatures,
250oC, 300oC and 350oC.
This biocrude showed high instability,
leading to the experiment at 350oC
where coking reactions were predominant,
encouraging the two-stage hydrotreating
investigation.