Heat and Electricity Production from Poultry Litter Waste: Downdraft Gasification of Biowaste based on Validated Computational Simulations

Underutilised fuel sources such as wastes, and by-products are currently being investigated for their potential to displace fossil fuels in multiple industries. The Northern Irish poultry industry has the potential to benefit from using the waste generated on-site as a fuel source, significantly reducing the amount of CO2 produced annually. The results can be achieved through downdraft gasification of poultry-litter, that can be converted into a producer gas for running a combined heat and power or organic Rankine cycle unit. The study was carried out through feedstock analysis, modelling of the process using ECLIPSE simulation software, and experimental analysis of materials in a pilot scale fixed-bed downdraft gasifier. Anaerobic digestate and miscanthus were also investigated for comparing the gasification potential of poultry litter. Models validated through experimental analysis were then applied to a case study based of a typical rural poultry farm in Northern Ireland. Results show that enough poultry waste is generated on site to produce the required heat and electricity for each shed. The choice of using an internal combustion engine or an organic Rankine cycle unit depends on the electricity demand of the farm. A techno-economic analysis of the system was also carried out to understand potential payback period for the system. Downdraft gasification coupled with CHP could have a payback of 10 years given the correct conditions, while downdraft ORC would be around 11 years.