Simulation of waste tire gasification in bubbling fluidized bed by Aspen: Contribution ratio analysis

Waste tire gasification in a bubbling fluidized bed is a promising thermochemical conversion technology that not only utilize waste tire but also produce energy. To reveal the gasification performance of waste tire in a bubbling fluidized bed, two Aspen models were developed to simulate the effect of gasification agent types (such as air, steam, carbon dioxide and their mixtures), considering chemical reactions that reached thermodynamic equilibrium (CRTM) or were controlled by kinetics (CRK). The simulated gas compositions (H2, CO, CO2 and CH4) and lower heating value (LHV) were compared with experimental data under various operating conditions. The results showed that CRK model exhibited much better performance than the CRTM model. These two models were further utilized to analyze the effect of gasification agent type on gas composition and LHV. The contribution ratios of different chemical reactions were detailed analyzed, such as hydrogen combustion, carbon monoxide combustion, methane combustion, carbon combustion, steam gasification, water gas shift reaction and carbon dioxide gasification. The established Aspen model for waste tire gasification in a bubbling fluidized bed could be served as a guideline for selecting operation conditions to achieve high hydrogen composition, carbon conversion, and gas yield.