Auto-Thermal Oxy-Steam Co-Gasification of Multi-Layer Plastic Packaging Waste and Diverse Biomass for Hydrogen-rich Syngas: A Simulation-Based Screening Study

Abstract

The non-recyclability of multi-layer plastic waste (MLP) and the underutilization of biomass present significant environmental challenges. This study developed and validated an Aspen Plus model for auto-thermal oxy-steam co-gasification of biomass-plastic mixture to produce hydrogen-rich syngas in a downdraft gasifier. Five different biomass-plastic mixtures involving MLP and five locally available biomass [Sawdust (SD), Rice Husk (RH), Palm Kernel Shell (PKS), Lemmon Grass (LG), Sugarcane Bagasse (SB)] were formulated and compared for feedstock selection using hydrogen yield under different MLP concentrations. Using the optimal feedstock, a parametric analysis was conducted to determine the ranges of Equivalent Ratio (ER) and Steam to Feedstock Ratio (SFR) that maximize hydrogen yield while maintaining thermal self-sufficiency. Among the fuel mixtures, the most promising was MLP-LG. The results showed that hydrogen yield increases with higher MLP concentration and SFR, but decreases when the ER exceeds 0.15. The optimum operating ranges for co-gasification of LG-MLP were determined to be 2.6 to 3.0 for SFR and 0.1 to 0.2 for ER, corresponding to a hydrogen yield of 133.57 to 133.73 g/kg feed. This study offers a practical approach to screening various plastic-biomass mixtures for their hydrogen-production potential prior to laboratory testing and industrial applications.