Catalytic fast pyrolysis is an efficient method to produce upgraded liquids for production of drop-in transportation fuels. Zeolite catalysts can be used to deoxygenate pyrolysis vapors either by in situ catalytic pyrolysis with pyrolysis and upgrading taking place in the same reactor or by ex situ catalytic pyrolysis with vapors from the pyrolysis reactor upgraded in a second catalytic reactor. We evaluated catalyst deactivation for these two configurations for catalytic pyrolysis of pine over HZSM-5 in a tandem microreactor. The catalyst and biomass were either placed in the same cup and rapidly heated (in situ), or the catalyst was placed in a separate reactor (ex situ). We monitored the changes in vapor composition as either the catalyst-to-biomass ratio was decreased or the amount of biomass passed over the catalyst bed was increased.Significant differences in the vapor concentrations and the catalyst deactivation behavior were measured, including distribution between oxygenates and hydrocarbons, type of oxygenates, and the degree of alkylation in the hydrocarbons. Light aldehydes and ketones were initially the most prevalent oxygenated compounds in both configurations, followed by the formation of furans and phenols. The yields of oxygenated compounds increased more rapidly for in situ than ex situ catalytic pyrolysis in these experiments, indicating more rapid deactivation for in situ catalytic pyrolysis.

Catalyst deactivation in ex situ and in situ catalytic fast pyrolysis of biomass

248th National Meeting (2014)

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