Simulation And Optimization Of Pre-Oxidation Device Of Multi-Pollutant In Coal-Fired Power Plants

This study is part of the 863 project "research and demonstration of desulfurization and mercury removal integration technology using circulating fluidized bed and multi-pollutant collaborative controlling technology of coal-fired flue gas". The research object is the pre-oxidation device for the circulating fluidized bed desulfurization tower of flue gas. The structure of the pre-oxidation device is optimized according to the results of numerical simulation. The effect of mix is simulated through the distribution of oxidant concentration at the exit of flue gas.After structural optimization, mixing effect of oxidant and flue gas is improved a lot.The optimized pre-oxidation device can blend the flue gas and oxidant well and provide condition for the oxidation reaction before the circulating fluidized bed desulfurization tower, which can improve the pollutant removal rate and the system stability.The introduction part mainly introduced the development of China's electric power industry, the present situation of air pollution control, brife introduction of integration technology of desulfurization and denitration and the development of multi-pollutant collaborative controlling technology. As the requirement of air pollutant emission of electric power industry is becoming more and more strict,multi-pollutant collaborative controlling technology will become one of the important developing direction of pollution control technology due to its unique advantages. In the second chapter, a 1:1 model is established using Solid Works and was pretreated.The meshing type is determined as the core hexahedral grid. In the third chapter, the structure of the pre-oxidation device is optimized through the analysis of the results of flow field simulation. The shape of the entrance, the diameter of the cylinder, the depth of the exhaust pipe and the half cone angle of the cone part is optimized. The inner flow field, effect of mixing and pressure loss are considered. After optimization,the aspect ratio is 1:1.5, the cylinder diameter is 14 m, the depth of the exhaust pipe is6 m, the half cone angle is 25 °. The optimized model solved the problem of the "short circuit" of flue gas effectively and reasonably, though the internal and outside cyclone is not so perfect. In the fourth chapter, the mix effect of flue gas and oxidant was simulated using transmission model of component. The oxidant concentration distribution of the outlet of flue gas in the optimized model is relatively uniform, the effect of blending of flue gas and the oxidant is greatly improved.