Comparison of In-Situ and Ex-Situ Catalytic Fast Pyrolysis of Pinewood and Phragmites Australis

One of the routes to provide sustainable chemicals and fuels from renewable sources that is receiving considerable attention is the catalytic pyrolysis of lignocellulosic biomass , such as pinewood and Phragmites Australis. Comparison of traditional in-situ catalysis , where the catalyst is directly in contact with the biomass at 500°C , to ex-situ catalysis where conditions are milder for catalytic upgrading of pyrolyzed vapors before condensation. These pyrolysis studies will be conducted in two reactors; CDS micropyrolyzer (µg scale) connected to a GC/MS and a bench scale tubular furnace (g scale). Both have an external fixed bed catalytic reactor downstream from the pyrolysis reactor. This study analyses the effect of various acidified amorphous silica based catalysts on the products formed from catalytic cracking during fast pyrolysis both in-situ and ex-situ for the two pyrolysis reactor systems. The preliminary results from the in-situ catalytic pyrolysis of pinewood at 500°C shows that mesoporous SBA-15 silica-based catalyst acidified with 75% monolayer coverage of sulfuric acid exhibits unusual behavior. The lignin derived phenolics are completely absent and the main condensable products are furfural and levoglucosenone (LGO). In contrast , under the same pyrolysis conditions and acid loading , an amorphous silica catalyst , having a larger porosity and a higher pore volume , gives a much broader distribution of products which includes alcohols and phenolics in addition to LGO and furfural. Based on these preliminary findings , additional work is underway to explore the structural and compositional features of silica based catalysts that are contributing to the high selectivity to LGO as well as looking at how the catalytic pyrolysis conditions and reactor configuration influence the product distribution. Resent results from these studies will be presented.