(592g) Catalytic Fast Pyrolysis of Isotopically Labeled Biomass and Plastic Blends

This study aims to address two problems important to agriculture, production of drop-in fuels from biomass and disposal of agricultural plastics via co-pyrolysis of both materials. Mixtures of biomass (cellulose and switchgrass) and polypropylene (PP) or polyethylene terephthalate (PET) were subjected to catalytic fast pyrolysis (CFP) at 650^oC in the presence of H-ZSM5 using a micro pyrolyzer coupled with GC/MS (py-GC/MS). Yields of the aromatic hydrocarbons, toluene, naphthalene and p-xylene, were enhanced for the CFP of mixtures of cellulose and plastic versus the CFP of biomass or plastic alone, suggesting a synergistic effect that enhanced the carbon efficiency of the CFP process.  To further probe this effect, CFP of uniformly labeled ¹³C biomass with non-labeled (¹²C) PP and PET in the presence of H-ZSM5 were co-pyrolyzed.  The resultant aromatic compounds had varying ¹³C_x¹²C_y compositions, proving that each reactant provides carbon to a pool from which aromatics are formed.  Further analysis allowed for a more detailed picture of the source of carbon for each individual product.  For example, it was found that for CFP of ¹³C biomass and PP pyrolysis, 69% of the toluene product was composed of at least four carbon atoms from PP. In this presentation the results of the catalytic co-pyrolysis of biomass and plastics and the isotopic labeling experiments will be discussed in detail in terms of yields of individual products, product selectivities and implications for the operative CFP mechanisms.