Pyrogasification of Blended Animal Manures to Produce combustable gas and blochar

摘要

The objective of this study is to evaluate the efficiency of a skid-mounted pyrogasificaiton system for producing combustible gas from from animal manures: chicken litter; swine solids; and swine solids blended with rye grass. The skid-mounted pyrolysis system by the US Innovation Group, Inc. (USIG, Indianapolis, IN) is a pilot-scale, proprietary thermochemical conversion system that can produce combustible gases from various carbon wastes such as auto shredder residuals (ASM), sewage sludge, municipal solid wastes (MSW), etc. Eight to 19 L of dried swine solids, chicken litter, and blended swine solids (29% rye and 79% swine solids, w/w) were pyrolyzed in the reactor at 620°C (893K) for two hours. Swine solids produced gas with the highest higherheating value (HHV), slightly below that of natural gas, followed by the blend and chicken litter. Relatively high S-containing gases were produced; dimethyl sulfide and methyl mercaptan concentrations were higher than the OSHA PEL limits. While the HHVof the chicken litter biochar was slightly below that of low rank coals, both swine-based biochars had HHVs in between high and low rank coals. Approximately 50% of the feedstock energy was retained in biochar, 25% in produced gases, and 25% in oil/tar.Manure biochars contained higher concentrations of P and K compared to that of original manure feedstocks; consequently, these have potential use as a low-grade fertilizer to improve soil fertility and crop yields.