Updraft gasification of poultry litter at farm-scale – A case study

•A critical evaluation of an on-farm, auto-thermal gasification unit is proposed.•The low ash melting behaviour of the feedstock demanded low temperature operation.•The cold gas efficiency was low (0.26) compared to wood fed gasification.•The tar/water emulsion had a pH of 9.6 and nitrogen content of 9.2wt.%db.•Zn and Cu exceeded the concentration limits for biochar certification. Farm and animal wastes are increasingly being investigated for thermochemical conversion, such as gasification, due to the urgent necessity of finding new waste treatment options. We report on an investigation of the use of a farm-scale, auto-thermal gasification system for the production of a heating gas using poultry litter (PL) as a feedstock. The gasification process was robust and reliable. The PL’s ash melting temperature was 639°C, therefore the reactor temperature was kept around this value. As a result of the low reactor temperature the process performance parameters were low, with a cold gas efficiency (CGE) of 0.26 and a carbon conversion efficiency (CCE) of 0.44. The calorific value of the clean product gas was 3.39MJm−3N (LHV). The tar was collected as an emulsion containing 87wt.% water and the extracted organic compounds were identified. The residual char exceeds thresholds for Zn and Cu to obtain European biochar certification; however, has potential to be classified as a pyrogenic carbonaceous material (PCM), which resembles a high nutrient biochar.