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BIOENERGY TECHNOLOGIES OFFICE
Gaseous Intermediate Technology
Thermochemical
Conversion
The elevated temperatures of thermo-
chemical conversion (300°C to 1,000°C)
expand the range of biomass feedstocks
that can be used by the bioindustry. The
ability to use a broad range of feedstocks
Gaseous intermediates are produced by
heating the biomass with less oxygen
than is required for complete combustion.
This approach may involve subjecting the
biomass to high temperatures to produce
a mixture of gases (gasification). These
gases can then be converted to fuels
and chemicals using catalysts or other
biological processes.
(see back page) helps to ensure an
adequate biomass supply across seasons
and spreads the economic and energy
security benefits across regions.
BETO is exploring the pathway for
upgrading one of these gaseous mixtures,
known as synthesis gas (or syngas), to
methanol. This pathway leverages ongoing
work in gasification and syngas cleanup
and offers opportunities to both improve
catalyst performance (enabling higher
yields) and intensify processing steps
Despite these advantages to using diverse
feedstocks, researchers recognize that
conversion technologies and supporting
processes are sensitive to variations
in feedstock characteristics (moisture
content, contaminants, etc.). BETO
works with industry and other partners
to explore ways to pretreat and blend
various types of biomass into uniform
formats with consistent properties. The
aim is to create commodities with pre-
dictable properties that meet established
criteria for efficient conversion.
(enabling their use in smaller facilities).
Pacific Northwest National Laboratory
has developed a multi-stage
hydrotreating process that can stabilize
the biocrude or produce a finished
hydrocarbon blend stock tailored for
end use or for input to a refinery.
Photo: PNNL
R&D Challenges for Gaseous
Intermediates
•
Demonstrate reliable reactor operation
•
Refine efficient gas-cleaning
technologies
Thermochemical conversion involves
deconstructing biomass and upgrading
the resulting intermediates into a range
of fuels and other products. Research in
thermochemical conversion focuses on
the production of either gaseous interme-
diates or liquid bio-oil intermediates and
their subsequent upgrading into fuels and
other products.
a finished fuel. Alternatively, the bio-oil
may be upgraded to an intermediate prod-
uct for further processing in a traditional
petroleum refinery. BETO research on
bio-oil intermediates currently focuses on
five pathways (three pyrolysis and two
liquefaction processes):
•
Develop improved catalysts for liquid
fuel production.
Bio-Oil Intermediate Technology
Biomass can be heated in the absence
of oxygen to ultimately produce a liquid
intermediate or bio-oil. The biomass
first undergoes either a pyrolysis or
liquefaction process to produce a vapor
mixture, liquids, and solids. Condensing
the vapor mixture yields a liquid with
bio-oil and aqueous layers (as oil and
water do not mix). The bio-oil can be
put through hydroprocessing, separation,
and fractionation steps to upgrade it into
•
•
Fast pyrolysis
Catalytic fast pyrolysis (ex-situ and
in-situ)
• Hydropyrolysis
•
•
Hydrothermal liquefaction
Solvent liquefaction.
R&D projects are improving thermochemical conversion routes for cellulosic and algal biomass.
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