(135g) Direct Coupled Catalytic Upgrading of Switchgrass Pyrolysis Bio-Oil Vapors

Direct coupled catalytic upgrading of complete bio-oil vapor from switchgrass pyrolysis was investigated over a Ce0.5Zr0.5O2 mixed oxide to produce higher carbon chain molecules from short aldehydes and carboxylic acids found in the bio-oil. The experiments were carried out in a single two-stage process where the vapor phase products from the pyrolysis reaction were fed directly to a fixed catalyst bed in a coupled reactor in series with the pyrolysis reactor. The final products were condensed to the liquid phase and collected for analysis. GC by GC analysis of products shows evidence of catalytic activity. Acetic acid and propanoic acid found in the bio-oil (from non-catalytic experiments) were converted to acetone and 3-pentanone, respectively, among other products, when reacted over the catalyst. This is consistent with our work on model compounds that short aldehydes and carboxylic acids are converted to higher chain aldehydes and ketones by way of aldol condensation and ketonization over mixed oxides catalyst. Reacting over the mixed oxide catalyst resulted in lower liquid yields when compared to experiments without a catalyst. The char yields remained the same while the gas yields, by difference, appear to have increased under these conditions. Deactivation and regeneration have been studied.