Currently,
there are two types of hydroprocessing catalysts available for converting
vegetable oils to diesel range hydrocarbons; supported noble metal catalysts (Pd
or Pt) and sulfide bimetallic catalysts (usually Mo- or W-based sulfide promoted
with Ni or Co). Disadvantages arise
however using these catalysts, as their limited availability and high price
makes the process not economically viable.
Noble metal catalysts are also very sensitive to catalyst poisons and
contaminants found in feedstock which can cause deactivation of the catalysts,
leading to the necessity of removing impurities from the feedstocks. The base metals in these hydrotreating
catalysts need to be maintained in their sulfide form in order to be active at
process conditions, therefore requiring a sulfurization co-feed to be added to
the feedstock. Furthermore, the
products obtained using these catalysts are essentially n-paraffins, solidifying
at subzero temperatures making them unsuitable for high quality diesel fuels,
kerosene, and gasoline compounds.
Wayne
State University researchers have developed a novel series of catalysts for
hydrotreating of fats and oils to be used for the production of biofuels,
especially green diesel. These
catalysts are prepared through impregnation method followed by carburization of
metal oxide precursors through temperature-programmed reaction (TPR) conducted
in a reactant gas stream. These are
bimetal carbide catalysts and provide the potential to convert all kinds of oil
feedstocks into green diesel fuels.
This
new technology utilizes the carbides of early transition metals which can
exhibit high activity, similar to the noble metals. These catalysts exhibit excellent
activity and selectivity for hydrodeoxygenation of triglycerides and free fatty
acids. The application of the technology also eliminates the need to add a
sulfur compound to a biomass-derived feedstock.
Commercial
Applications:
·
Convert
fresh and unrefined waste oils into green diesel
Technological
Advantages:
·
Substantially reduce
the production costs of biodiesel
o
Reduced production
complexity
o
Lower operating
costs
o
Convert unrefined or
waste oils into green diesel
·High yield-
o
Approximately 95%
yield of green diesel was obtained by hydroprocessing of soybean
oil
o
Yield of green diesel
is 80% greater than commercially available hydrocracking
catalysts
·
Long Catalyst Life-
nearly double the active lifetime of existing catalysts (850hrs+ vs. 450hrs with
current hydroprocessing techniques)
·
Reduce the
engineering and environmental problems caused by sulfurization reagents in the
traditional hydroprocessing reaction.
Patent
Status:
Provisional
patent on file