(35f) Core-Shell Structured ZSM-5/MCM-41 Catalysts for Catalytic Fast Pyrolysis of Biomass

Core-shell
structured ZSM-5/MCM-41 catalysts for catalytic fast pyrolysis of biomass

Lei
Yu ^a, Oluwole Ajumobi ^b, Vijay John ^b, Julia
Valla ^a

^a Department of
Chemical and Biomolecular Engineering, University of Connecticut, Storrs 191
Auditorium Road, Unit 3222, Storrs, CT 06269-4602, United States

^b
Department
of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA
70118-5674, United States

Biomass
is considered as a sustainable and renewable resource for energy and fuel production.
Biomass pyrolysis is a thermochemical process that converts the biomass
building blocks (cellulose, hemicellulose and lignin) into organic monomers,
the bio-oil, which can potentially substitute the traditional transportation
fuels. However, bio-oil generated from biomass has undesired properties, such
as high concentration of oxygenates, high viscosity and low heating value.
Hence, bio-oil has to be upgraded before its use. Catalytic fast pyrolysis
(CFP) is a promising technology that can be used to directly convert biomass
into upgraded bio-oil. ZSM-5 is considered as one of the best catalyst in CFP
process due to its shape selective pore structure. However, coke formation and
fast deactivation of ZSM-5 hamper the commercialization of this technology.
Therefore, the modification of ZSM-5 to prolong the life time of catalyst is of
high interests. In this study, novel core-shell structured catalysts using
ZSM-5 as active cores and MCM-41 as shell were prepared. The prepared catalysts
were characterized by N₂ sorption-desorption, X-ray powder
diffraction (XRD), scanning electron microscope (SEM), transmission electron
microscopy (TEM) and pyridine adsorption. Catalytic experiments were conducted in
situ with different catalyst to biomass (miscanthus × giganteus) ratio. The
solid products after pyrolysis were analyzed by TGA to measure the amount of
coke. Ex situ regeneration experiments were also performed to evaluate
the regeneration ability of synthesized catalysts. It was concluded that the
core-shell structured catalysts could effectively reduce the formation of
indenes and naphthalenes and therefore decrease the amount of coke. The
oxygenate yields were also lowered. Most importantly our experimentas results
demonstrated that our novel core shell catalysts had a better regeneration
performance than pure ZSM-5, allowing for multiple pyrolysis/regeneration
cycles without significant loss in activity. Our study suggested that our novel
core-shell structures can be promising catalysts for the catalytic pyrolysis of
biomass to fuels.