(738e) Microwave Assisted Fast Catalytic Pyrolysis and Gasification for Solid Wastes Conversion and Utilization

Authors: 
Ruan, R., University of Minnesota
Various solid wastes, e.g., as crop residues, processing byproducts, food wastes, municipal solid wastes, and waste plastics and used tires are potential feedstock for production of renewable energy, chemicals and materials.  Gasification and pyrolysis are efficient ways for conversion and utilization of these solid wastes. Fluidized bed processes are the most common methods employed in fast pyrolysis and gasification. Major issues with the fluidized bed processes include complex and expensive system and process, high ash particles in products due to violent agitation, low energy density of syngas due to the dilution by carrying gases, etc. In this presentation, we will present our improvement and new development of a fast microwave assisted downdraft catalytic pyrolysis and gasification processes using novel microwave heating mechanism in which microwave absorbents and catalysts are used to significantly improve the heating characteristics, and the yield and quality of the desirable products. Solid feedstocks are directly dropped on to the hot microwave absorbents efficiently maintained at desirable temperatures, resulting in higher temperature rise of the feedstock and therefore much more efficient absorption of the microwave energy also, and in turn instant gasification and pyrolysis. A separated packed-bed catalysis for the volatiles was also developed to improve the quality and yield of the pyrolytic and gasification products. Results and discussion on the effects of key process variables such as microwave absorbent type, particle size, and loading, microwave power input and control, feedstock loading method, raw material and catalyst temperatures, and ratio of raw material and catalyst loading on product yields and quality, and energy consumption will be presented.