Syngas production from fast pyrolysis and steam gasification of mixed food waste

Food waste generation is a worldwide phenomenon and disposing off it in an environmentally benign way has been a challenge. Thermochemical processes have the potential for not only processing mixed food waste effectively from an environmental point of view but also producing bioenergy in all three forms: solid (biochar), liquid (bio-oil) and gas (syngas). In this study, two thermochemical processes - fast pyrolysis and steam gasification - aimed for producing syngas as main product were carried out at three different temperatures: 600 degrees C, 700 degrees C and 800 degrees C, and resulting syngas was characterised and compared for syngas yield, syngas composition, hydrogen yield and high heating value (HHV). The steam flow rate (SFR) was maintained at 0.625 mL min(-1) for all gasification experiments. The syngas yield obtained from steam gasification was higher (1.2 m(3) kg(-1)) than the syngas yield from fast pyrolysis (0.81 m(3) kg(-1)). In addition, the hydrogen fraction was much higher in syngas from steam gasification (63.58%) than that from fast pyrolysis (45.03%). Furthermore, carbon conversion efficiency (CCE) and apparent thermal efficiency (ATE) were determined to compare the performance of these two processes. CCE was higher (63.6%) for steam gasification than that for pyrolysis (52.3%) which suggested that steam gasification was much more effective than fast pyrolysis to produce syngas of higher quality.