Structural Optimization Design Of SCR Denitrification System With Double Inlets And Outlets And Performance Research Of Flow Deflectors Erosion

The coal-fired power plant occupies the dominant position in the NO_x emission sources,the flue gas denitrification has become an unavoidable problem air pollution control in our country. The selective catalytic reduction technology is the most widely used denitration method at home and abroad. In order to ensure the flow field and concentration field distribution to meet the process requirements, it is very important to optimize the structure of denitration system. In the engineering application,usually by adding and changing the layout of flow deflectors to optimize the denitrification system. At present, there are very few reports about the flow deflectors erosion caused by fly ash particle erode.Aim at the denitrification system of a coal-fired thermal power plant, the internal flow field and concentration field in the denitrification system are studied by using the method of computational fluid dynamics in this paper. The flow field and concentration field distribution are optimized by change the arrangement of flow deflectors. At the same time, the flow deflectors erosion under different particle size and flow rate conditions are simulated by using the erosion equation. The conclusions are as follows:(1) The structure optimization schemes of denitrification system are proposed in this paper. By installing the flow deflectors and changing the flue structure, the relative standard deviation of velocity and ammonia concentration at the first catalyst layer has been significantly decreased.Respectively from 18.15% ?13.83% down to 6.24%?4.62%, the denitration process requirement has been satisfied.(2) Caused by effect of the narrow and variable cross-section of flue structure, the ammonia concentration at the first catalyst layer are serious uneven. The simulation results show that ammonia concentrationdistribution has been improved significantly after added the vertical flow deflectors.(3) By numerical calculation of the erosion wear of flow deflectors,The wear parts have be predicted. Among which, In the fly ash particle size is between 0.3-200 microns, the erosion wear rate first decreases and then increases with the increase of particle size. Under the condition of different flue gas flow rate, the erosion on the guide vane location basically remain unchanged, but as the velocity increases, the erosion rate also increases accordingly.