Multi-Utilization of Swine Manure as a Bioenergy Feedstock: Carbonization and Combustion

The use of animal manure and other organic-based waste products as bioenergy feedstocks is gaining interest for waste-to-bioenergy conversion processes. While thermochemical conversion of animal manure via combustion, pyrolysis, and gasification is becoming a new frontier of manure treatment; there is relatively little known about its behavior when subjected to these high-temperature energy-conversion processes. In this study, the pyrolytic and oxidation behaviors of three different swine manures (flushed, separated solids, and lagoon sludge) were examined by thermal analyses using simultaneous thermogravimetry (TG) and differential thermal analysis (DTA). Pyrolysis and oxidation occurred in distinct stages of weight loss that initiated at similar temperatures. Within manures, pyrolysis and primary oxidation initiated at similar temperatures yet had distinctly different activation energies. Oxidation of the manures had lower associated activation energies. Both degradation processes had high reaction orders that suggest that devolatilization was complex.