Co-gasification of biomass and polyethylene: a simulation study by considering tar formation

Energy recovery from biomass gasification has attracted increasing attention. However, carbon content in biomass is low relative to plastics and fossil fuels, causing a significant reduction in the calorific value of the produced syngas. The addition of a high-carbon fuel (e.g., coal and polyethylene) to biomass can improve the quality of the syngas. In this study, a comprehensive process model was developed for co-gasification of rice husk (RH) and polyethylene (PE) using Aspen Plus simulator under steady-state condition. The model is first validated by comparing with experimental data collected from a fluidized bed co-gasification system. Subsequently, the effects of gasification temperature, steam-to-fuel ratio (STF) and PE ratio (PR) on the produced gas composition, syngas yield, producer gas caloric value, tar content in the producer gas, H-2/CO, H-2 yield and gasification efficiencies are studied. The results showed that, increasing PR could improve the gas yield, H-2/CO and the higher heating value (HHV) of the syngas. Higher PR also enhanced the production of H-2 and tar conversion. However, as STF increased, the HHV of the syngas, and gasification performance reduced. Higher temperature was beneficial for H-2 production, tar conversion, and gas yield, but reduced H-2/CO.