Abstract:

In China, the combustion of municipal solid waste （MSW） in the incinerator is unstable due to the high moisture, low heat value and various compositions of the waste. In order to solve this problem, the method of computational fluid dynamics （CFD） is adopted to optimize the incineration of MSW with invariable composition. At a constant flow ratio of the primary air to the secondary air, a diffusion model for the packed bed and a transportation model for the components are established by adjusting the feeding ratio of the primary air in each air chamber. The two models are then used in different air distribution conditions to calculate the components and temperature of the gas on the bed surface as well as the temperature distribution in the furnace over the bed. Calculated results show that the variation of flow ratios in different air chambers greatly affects the gas combustion, furnace temperature and flow field in the incinerator, but slightly affects the burn-out performance of coke. Moreover, at a flow ratio of 1.4： 2. 8： 2.8： 2： 1, the furnace temperature in the incinerator reaches 1085.7K and the content of unburned carbon in the ash is up to 3.19 %. The calculated results accord well with the measured ones.

Key words: incinerator, combustion optimization, numerical simulation, municipal solid waste