Catalytic Hydrodeoxygenation of Biomass Pyrolysis Vapor Model Compounds over Molybdenum Sulfide Catalysts: Influence of Support, H₂S and Water

Conventional fast pyrolysis of biomass produces a high yield of bio-oil through well-established technologies1. The produced bio-oil must be further processed in order to decrease the content of oxygen(from 15-30 wt% down to <1 wt%) and thereby enhance important fuel properties such as heating value,acidity and stability1-2. Upgrading of condensed pyrolysis oil is challenged by severe polymerization andcoking upon heating. Instead, it is proposed to perform pyrolysis in the presence of hydrogen and an HDOcatalyst for immediate stabilization and upgrading of reactive pyrolysis products. Downstream deep HDO potentially ensures removal of oxygen down to <1 wt%. A schematic diagram for such a process is shown inFigure 1. A simplified bench scale setup is being constructed at DTU Chemical Engineering with a plannedcommissioning in Spring 2016. With a capacity of 100 g/h solid biomass, the aim is to provide a proof-ofconceptfor the continuous conversion of solid biomass to low oxygen, fuel-grade bio-oil.In this contribution, a combined experimental, characterization and theoretical study of catalytic hydrodeoxygenationof biomass pyrolysis vapor model compounds over molybdenum sulfide catalysts ispresented. The influence of support, H2S and water on activity, selectivity and deactivation is investigated.