Ex-situ vapor-phase upgrading of pyrolysis vapors using layered double hydroxide catalysts
Greer, C. E., S. Acado, P. Kim, N. Labbe, and S. C. Chmely.  2014.  Abstract from scientific meeting.

Abstract:
As annual energy consumption continues to rise, energy resources such as fossil fuels continue to decline. Finding alternatives to petroleum for the production of fuels, products, and power is critical. Bio-oil, the liquid product of fast pyrolysis, is a promising substitute for petroleum because it can be produced from renewable resources such as switchgrass and hybrid poplar. However, bio-oil usually has a high water content, high viscosity, and high total acid number. These characteristics make bio-oil highly corrosive, difficult to homogenously mix with petroleum oil, and difficult to pump and transport. Deoxygenation of bio-oil alleviates many of these negative properties. Layered double hydroxides (LDHs) are part of a class of anionic clays formed by metal hydroxide layers with compensating anions and water molecules in the interlayer region. LDHs form mixed metal oxides by calcination, and basic metal oxides have been shown to be moderately effective at removing oxygenated species from bio-oil. We have conducted an investigation of the effects of basic catalyst materials synthesized from LDH precursors on the composition of biomass pyrolysis vapors using pyrolysis gas chromatography/mass spectrometry (py-GC/MS). This method proved useful in detecting changes in the composition of pyrolysis vapors. We will demonstrate that these catalyst species substantially decrease the amount of highly oxygenated compounds such as levoglucosan in pyrolysis vapors while simultaneously increasing the amount of furans such as HMF and dimethyl furan. We hypothesize that these changes will favorably affect the composition of the resulting bio-oil. Catalyst synthesis, characterization, and screening results will be presented.