(369d) Production and Analysis of Pyrolysis Oils from the Fluidized-Bed Co-Pyrolysis of Agricultural Plastic Waste and Biomass Mixtures

Mullen, C. A., USDA Agricultural Research Service
Dorado, C., Agricultural Research Service, USDA
Boateng, A. A., USDA-ARS

Pyrolysis of biomass produces bio-oils that are highly oxygenated and acidic. Along with high water content and low higher heating values (HHV), these bio-oils are also unstable. Catalytic pyrolysis can alleviate these issues by producing bio-oils that consist of more desirable aromatic hydrocarbons. However, the low H/C nature of biomass leads to inefficient biomass carbon conversion and produces a great deal of CO, CO2 and coke that eventually causes catalyst deactivation. The incorporation of a co-feedstock with a higher H/C ratio could address these issues. The catalytic co-pyrolysis of biomass and plastic has been shown to produce products that incorporate C from both feedstocks and increases the production of desirable aromatic hydrocarbons. The use of agricultural plastics as a co-feed for the pyrolysis of biomass has the added benefit of providing a method for disposal of this waste. Switchgrass and used hay bale covers composed of polyethylene (PE) were mixed and subjected to catalytic pyrolysis in the presence of HZSM5 in a bench-scale fluidized-bed system. The catalytic pyrolysis oils were analyzed and compared to oils produced via regular pyrolysis and pyrolysis using a tail-gas reactive pyrolysis (TGRP) method. Yields were tracked on a mass and carbon basis. Complete chemical and physical property analysis including CHNS/O composition, energy content, and acidity were conducted. Chemical compositions of the pyrolysis oils were determined and compared with those produced from biomass alone.