Comparison of green waste gasification performance in updraft and downdraft fixed bed gasifiers

This study aimed to investigate the gasification potential of municipal green waste in different fixed-bed gasifier configurations as updraft and downdraft. Both reactor systems were constructed from stainless-steel with a cyclone separator to increase synthesis gas yield and reduce tar production. Green waste collected from parks and gardens by Manisa Metropolitan Municipality, Turkey, was used in the experiments. After full-characterization of green waste, gasification experiments were performed above 700 ? to produce syngas with more than 40% (volumetric) H-2 and heating value around 12.54 MJ/ Nm(3). Dry air (DA) and pure oxygen (PO) were used as gasification agents. DA was applied with the flow-rates ranged between 0.4 and 0.05 L/min while the flow-rate of PO was 0.01 L/min. The maximum H-2 production as 45 vol% was obtained in downdraft reactor while it was about 51 vol% in updraft system. CH4 production was obtained as higher value (app. 19 vol%) in downdraft reactor than that (13 vol%) in the updraft one. In the experiments with DA above 700 ?, the H-2/CO ratio varied between 1 and 3, and in the experiments with PO, it increased up to a maximum value of 4. The study has found a suitable set of gasification process parameters for two reactor systems. Therefore, the findings have been compared and discussed in detail. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved