Product yields from the slow pyrolysis process of poultry litter

Thermochemical conversion provides an economical and environmentally sound route to dispose animal waste. This conversion process is particularly attractive for the disposal of poultry litter, allowing both biomass valorisation for energy production and safe disposal of the waste material. In the present study, different experimental and analytical techniques were used to investigate the slow pyrolysis process of poultry litter. Experimental runs to simulate a slow pyrolysis process were performed in a fixed bed reactor at constant temperature (400-800 °C) under nitrogen flow. Products obtained were investigated both quantitatively and qualitatively using analytical methods. On-line FTIR techniques showed that the most significant compounds in the produced gas are carbon dioxide, carbon monoxide and methane. Elemental analysis revealed the elemental composition of poultry litter and of pyrolysis products, which contain significant amount of nitrogen and sulphur. The fate of these elements during the pyrolysis process was clarified. GC-MS results uncovered the compounds present in the bio-oil and help to investigate bio-oil potential use as a biofuel. Altogether, this study allows a better understanding of the slow pyrolysis behaviour and its potential in waste-to-energy applications.