Heterogeneous catalysts for advanced bio-fuel production through catalytic biomass pyrolysis vapor upgrading: a review

Nowadays concerns regarding fossil fuel resources depletion as well as environmental issues attributed to CO2 accumulation in the atmosphere force communities toward utilizing biomass as a substitute fuel source which is environmentally secure and renewable. Pyrolysis bio-oil from biomass comprises varieties of undesirable oxygenate and heavy compounds and has to be treated before feeding to biorefineries. Catalytic biomass pyrolysis vapor upgrading presently seems to be a techno-economical process toward production of fuel-like components. However, selection of stable and productive catalyst(s) to yield desirable chemicals with low coke formation is a great challenge. The three most important classes of catalysts comprising microporous zeolites, mesoporous catalysts and metal based catalysts are utilized for vapor phase bio-oil upgrading. This study offers a comprehensive review on catalytic biomass pyrolysis vapor upgrading by emphasizing particularly on catalyst types and properties, coke formation over catalysts and catalytic process conditions.