Towards enhanced catalytic reactivity in CO2-assisted gasification of polypropylene

Abstract The role of catalyst (Ni/Al2O3) position on improved gasification of polypropylene (PP) in CO2 atmosphere using a fixed bed reactor at 900 °C was examined and the results compared with non-catalytic gasification. The catalytic gasification included in-situ and quasi-in-situ (with feedstock located close to but not directly in contact with the catalyst) configuration. Results are reported on the evolutionary behavior and yield of carbon monoxide (CO), hydrogen (H2), hydrocarbons (CmHn) and total syngas. Compared to non-catalytic gasification, in-situ, and quasi-in-situ catalytic gasification produced higher H2 by 120.5% and 137.1%, higher CO by 38.2% and 24.0%, higher CmHn by 57.1% and 98.2%, and higher total syngas by 44.1% and 43.8%, respectively. CO2-assisted gasification of PP with Ni/Al2O3 catalyst significantly enhanced the gases evolution rate and improved the syngas yield. Results revealed better catalytic activity with quasi-in-situ configuration in the thermal decomposition of PP into H2 and CmHn than in-situ catalytic configuration. However, in-situ catalytic configuration provided more CO under similar gasification conditions. Approximately 0.8, 1.1 and 1.0 kg of CO2 could be consumed per kg of PP feedstock to generate syngas energy yield of 27.5, 43.1 and 48.1 MJ with non-catalytic, in-situ and quasi-in-situ catalytic configuration, respectively, suggesting efficient utilization of both CO2 and PP waste for clean and efficient energy production.