Numerical Simulation Of Municipal Solid Waste Combustion In A Fixed Bed

The combustion process of municipal solid waste (MSW) on the moving grate is studied and simulated it by CFD codes. The results of simulation and experiments are compared and analyzed. Detailed combustion process parameters of MSW, as the temperature during the combustion, the losing weight and the gas produced from the fuel, are measured and simulated. At last, the combustion processes at different primary air flow-rate are simulated and analyzed.In simulation, the drying process of MSW combustion is modeled by diffusion model. The separating out process from fuel for volatiles is modeled by one step reaction model. The char combustion is modeled by diffusion-kinetics model.From the results of simulation and experiments, the drying process occupies the most part of the whole combustion time of MSW. Due to the heat source at top of fuel, heat is transferred to top of fuel by radiation and to the bottom by conduction, heat convection and radiation. With this heat transfer process, fuel goes through the drying, pyrolysis, char combustion and burnout.Five primary air flow-rates are chosen as different experiment conditions and simulated. The results of simulations and experiments are compared and analyzed. Simulation and experiment results agreed with each other well at two experiment conditions. The results about CO is aborted, and the results about O₂,CO₂ only can give the trend on combustion.This thesis shows that the simulating model can model the combustion of MSW. The results from modeling can show the combustion process, and make us know how the heat transfers in the fuel and get the maximum temperature value. The simulation can predict the trend about combustion, but it is still some distance to tell the quantity of amount and time of gas yielding from fuel.