"Evaluation of available technologies for chicken manure energy conversion and techno-economic assessment of a case study in Italy"

Chicken manure used as a natural fertilizer, given its high Nitrogen content, requires key actions in odor control that are often difficult to carry out resulting in an image loss for the company. Manure land-filling however is costly as well as incineration and this latter does still require odor control. Energy conversion from chicken manure may turn the cost into an earning that could payback both the investment and the image loss for odorous emissions. In this optic the paper analyses the different technologies that are available for energy conversion from chicken manure namely incineration, gasification, pyrolysis and anaerobic digestion with application to a real case. A large scale egg selling company in central Italy, with three production sites, was selected and its mass and energy flow balance assessed with particular reference to manure production and electricity consumption and expense. Five different technologies were then considered for energy conversion from chicken manure both for a single production site (microscale) and for the three (small scale). Grate incineration with steam production from exhaust gases was considered and discarded because of the too small scale. BTG gasification technology and IPRP pyrolysis technology presented by the authors, were evaluated and the techno-economic assessment showed interesting pay back time with medium to high investment costs and medium efficiencies. Pyrolysis technology with gas-steam combined cycle was considered but the economics show a very high pay back for the investment due to the small scale. Finally anaerobic digestion was evaluated showing the lowest investment cost and efficiency but an interesting payback period also considering that no public financing was considered. This latter solution has been presented to the company that will decide whether to finance the project.