Solvolysis and Mild Hydrogenolysis of Lignin Pyrolysis Bio-Oils for Bunker Fuel Blends

The projected depletion of fossil resources has initiated research on new and sustainable
fuels which can be utilized in combination with conventional fuels. Lignocellulosic biomass,
and more specifically lignin, can be depolymerized towards phenolic and aromatic bio-oils
which can be converted downstream into bunker fuel blending components. Within this
study, solvolysis under critical ethanol conditions and mild catalytic hydrotreatment were
applied to heavy fractions of lignin pyrolysis bio-oils with the aim of recovering bio-oils
with improved properties, such as a lower viscosity, that would allow their use as bunker
fuel blending components. The mild reaction conditions, i.e., low temperature (250 ◦C),
short reaction time (1 h) and low hydrogen pressure (30–50 bar), led to up 65 wt.% recovery
of upgraded bio-oil, which exhibited a high carbon content (63–73 wt.%), similar to that of
the parent bio-oil (68.9 wt.%), but a lower oxygen content and viscosity, which decreased
from ~298,000 cP in the parent lignin pyrolysis oil to 526 cP in the hydrotreated oil, with a
10%Ni/Beta catalyst in methanol, and which was also sulfur-free. ... mehrThese properties permit
the potential utilization of the oils as blending components in conventional bunker fuels.