(633a) Upcycling Plastic and Coal Wastes into Syngas By Steam Gasification

Plastic waste is primarily disposed of in landfills due to difficulties in recycling and a lack of economic incentives. A promising approach to address this issue is steam gasification which thermally converts plastic waste into fuels and value-added chemicals, such as hydrogen and syngas. In this study, low-density polyethylene (LDPE) and coal refuse (CR) from thickener underflow were pelletized together at varying weight contents to create a coal-like feedstock. The steam gasification of this mixture was investigated in a drop tube reactor system equipped with an on-line mass spectrometer and a tar-collecting apparatus. The effects of reaction temperature, blending ratio, and catalyst composition on conversion, product distribution, syngas quality, and tar reforming efficiency were examined. Our results showed that the carbon conversion and product distribution were strongly influenced by the reaction temperature (800-1000 °C), with higher temperatures promoting hydrogen and carbon oxides formation and suppressing tar formation. A decrease in LDPE content in the feedstock increased syngas yield but decreased syngas quality, suggesting a synergistic interaction between LDPE and CR. Moreover, incorporating Fe₂O₃ during steam gasification significantly improved tar reforming efficiency. Other catalytic systems from natural and waste sources are being explored to further enhance syngas formation and allow control of hydrocarbon products. We have demonstrated that the co-utilization of plastic and coal wastes is a viable solution to reducing waste and producing useful products, thereby providing a pathway to a circular economy.