Whole process simulation of MSW gasification and melting system based on Aspen Plus

The gasification and melting process of municipal solid waste (MSW) can reduce the formation of dioxins and melt heavy metals, which is a clean and efficient solid waste treatment method. At present, most of the research is on the pyrolysis characteristics of MSW and the generation and emission of pollutants, while the research on the influence between the modules of the gasification and melting process system and the linkage change process of material flow and energy flow between each reactor is insufficient. The whole process simulation of MSW gasification and melting process was carried out by using Aspen Plus simulation platform based on Gibbs free energy minimization principle. The effects of waste drying temperature, waste moisture content, gasification temperature, gasification medium and ash melting point on the process node parameters, material flow and energy flow were analyzed, and the optimized process flow and operation parameters were proposed. The results showed that when the moisture content of garbage was 9%, the simulation of garbage pyrolysis could achieve energy self-sufficiency through flue gas circulation. Under the same conditions, different gasification agent media had the highest gasification efficiency using water vapor as the gasification medium, and the optimal process was achieved at a gasification temperature of 850 ℃ and a water vapor equivalence ratio of 50%. When the char produced after gasification was burned in the melting furnace to meet the ash melting point temperature, the increase of ash melting point made the proportion of gasification agent, the effective gas molar flow of gasification gas and the carbon conversion rate decreased continuously. The changes of material flow and energy flow under different working conditions has guiding significance for practical engineering.