Design Of Flow Field And Research Of Optimization On Ammonia Injection For Selective Catalytic Reduction System In Coal-Fired Unit

Selective catalytic reduction?SCR? technology has high efficiency and good reliability. It is a widely used technology of flue gas nitrogen oxide control in coal fired power plant. The analysis of the flow field of the SCR system and the reasonable optimization strategy for the injection of ammonia have important theoretical value and engineering significance to ensure the efficient, safe and economic operation of SCR. In this paper a 330 MW unit SCR de denitration reaction system as the research object, the theoretical simulation and experimental method to optimize the flow field of the SCR system research and design, and in the analysis of velocity field and concentration field based, put forward rational spraying ammonia optimization strategy and ensure the efficient operation of the economic system.The initial flow field of the SCR reactor was simulated to find the defect by the Fluent. Then, design the structure, size and position of gate leafs, in order to obtain satisfied velocity and concentration distribution at the entrance of catalyst layers. Besides, some other parameters such as temperature, pressure were considered. The results show that: the diversion components inside the flue can significantly improve the uniformity of velocity and concentration distribution.According to principle of similitude, a physical model was built to test and verify the result of numerical simulation. In this experiment, ammonia was substituted by Carbon dioxide; catalyst layers were substituted by porous plate; The pressure loss of the catalyst layer is controlled by the drilling rate. Then measure the distribution of velocity and concentration, incident angel and the pressure loss of the system. Based on these experiments, optimize the numerical modeling result.Based on the numerical simulation and physical model experiment, the distribution of gas flow field and NH₃ concentration field are found out, in order to obtain a better mixing effect, the results of the analysis and put forward the optimization measures for the injection of ammonia in the district. Control the injection volume of each area, the partition ammonia injection mode by analyzing the flow field nonuniformity can further optimize the uniformity of NH3 concentration distribution and can significantly guide the power plant debugging.