THERMOCHEMICAL CONVERSION: AN INTRODUCTION TO FAST PYROLYSIS - Biomass as a Sustainable Energy Source for the Future - page 379

A short overview of the current status of processing pyrolysis oil in several appli-
cations to produce energy fuels and/or chemicals is given below (for more informa-
tion, see, e.g., Czernik and Bridgwater, 2004 or Bridgwater, 2012):
Boilers : Successful combustion tests of pyrolysis oil in boilers and furnaces for the
production of heat and power have been carried out. This is especially interesting
for replacement of fuel oil by pyrolysis oil for heating purposes.
Engines : Direct combustion of pyrolysis oil in standard diesel engines suffers
some difficulties in the ignition, corrosiveness, and coking. However, for larger
(e.g., ship) and stationary diesel engines, it is expected that these problems
can be overcome by engine modifications and blending the pyrolysis oil with
alcohols.
Gasification : Gasification of solid biomass is already a proven technology to
produce syngas. The advantages of the gasification of pyrolysis oil compared
to the gasification of solid biomass are the increased volumetric energy density
(transportation) and easier feeding. Using pyrolysis oil, high-temperature
gasification (entrained flow) tests have been successful, while low-temperature
gasification using a catalyst suffers from rapid catalyst deactivation.
Chemicals : Chemicals, including highly oxygenated ones, are currently almost
always produced from fossil fuels. It may be simpler and energetically attractive
to produce these chemicals from biomass. Chemicals such as acetic acid, acetol,
glucose (levoglucosan), and phenols can be produced via further processing of
the oil or its fractions or can be directly extracted from the oil. Separation tech-
nology will play a very important role in the production of chemicals from bio-
oils. Improving the selectivity toward compounds more readily suitable for the
production of fuels and chemicals would increase the value of the pyrolysis proc-
ess. An interesting process concept to increase the selectivity toward anhydro-
sugars is via demineralization of the biomass, which can be done using the acids
produced during the process, prior to pyrolysis (see Oudenhoven et al., 2013).
Pyrolysis might become one of the technologies linking thermochemistry and
biotechnology. More detailed studies of pyrolysis reactions using novel exper-
imental and theoretical tools are likely to result in a substantial increase of the
yield of anhydrosugars produced, which could make the production and fermen-
tation of these sugars technically viable. New and more efficient microorganisms
able to directly ferment anhydrosugars with higher resistance to bio-oil inhibitors
are expected to be developed (see Kersten and Garcia-Perez, 2013).
Cofeeding in existing refineries : Recently, many studies have been published on
cofeeding upgraded pyrolysis oil in crude oil refineries in selected processes
such as FCC, hydrodesulfurization (HDS) or hydrocracking. This route makes
use of available infrastructure and generates existing products such as gasoline
and diesel for existing markets. At small, microunit scale, it has been shown that
these upgraded oils can be corefined yielding fuels in the gasoline and diesel
range. Upgrading involves deoxygenation and stabilization of pyrolysis oil,
i.e., minimizing the tendency to form coke during refining (heating). This is