Synergistic Effects of Biomass-polyethylene Co-gasification: A Simulation Approach

A parametric study on syngas production from the co-gasification of biomass and plastic waste using oxygen as the gasifying agent was conducted using an Aspen Plus simulation. The study examined the effect of plastic content and its synergistic interaction with biomass. Key operating parameters, including equivalence ratio (ER) and blend ratios were varied to assess their impact on hydrogen and carbon monoxide concentrations, the H2/CO ratio, lower heating value (LHV), gas yield (GY), and cold gas efficiency (CGE). Increasing plastic content enhanced H2 concentration but reduced CO levels. At ER of 0.1, a 75% polyethylene and 25% biomass mixture achieved 56% H2 while pure biomass yielded 56.4% CO. The highest CO content in the blended feedstock (54.2%) was obtained at ER of 0.22 with 25% PE and 75% biomass. The H2/CO ratio of 2, ideal for synthetic fuel applications, was achieved at an ER value below 0.4 for 50% and 75% PE mixtures. While the co-gasification improved H2 production, LHV showed no enhancement, indicating no additional energy benefits from co-gasification. However, the GY exhibited synergy, as co-gasification produced more syngas as ER increased, CGE improved due to synergy, particularly at ER values below 0.4 demonstrating enhanced feedstock conversion efficiency. These findings suggest that co-gasification enhances syngas production and overall quality, making it a highly viable process for improving the efficiency of waste-to-energy technologies. In addition, biomass-polyethylene co-gasification shows potential in improving syngas quality, addressing challenges like low H2/CO ratios and low LHV, which are common issues in conventional biomass gasification.