低尘SCR系统单孔催化剂模拟研究

Simulation on Single Channel Catalyst in Low-dust SCR System

在Eley-Rideal化学反应动力学机理基础上,建立了SCR催化剂孔道表面一维模型,重点分析了低尘布置方式下不同参数(催化剂尺寸、反应温度、反应物浓度等)对催化剂脱硝效率的影响。结果表明:随着催化剂沿程长度增加,反应物浓度降低,化学反应速率下降。在孔内流速为4.5m/s、反应湿度为610K时,脱硝效率最大约为75%,温度过高或过低均会降低催化剂脱硝性能。在入口NO浓度为500mg/m^3时,要满足脱硝效率达78%以上,需要氨氮摩尔比大于1.1。适当地降低烟气流速有利于提高脱硝效率,但会增加SO_2氧化,因此在追求较高脱硝效率同时应考虑对SO_2氧化的影响。

One-dimensional model of the selective catalytic reduction(SCR)reactor were established based on Eley-Rideal kinetic mechanism and it was used to analyze the influences of different parameters such as size of catalyst、reaction temperature and concentration of reactants on denitration efficiency in low-dust condition.The results show that the concentration of reactants and the chemical reaction rate decline along the reactor axis direction.The best temperature is about 610 K when the gas velocity is 4.5 m/s.Either the temperature is too high or too low has an adverse effect on denitration.To realize the denitration efficiency of 78%,the ammonia nitrogen molar ratio needs to be set at least at 1.1 when the inlet NO x concentration is 500 mg/m 3.Reducing the flow rate appropriately is conductive to improve the denitration efficiency.However,the lower the flow rate is set,the easier SO 2 is oxidized.Therefore,the oxidation of SO 2 should be controlled while persuing higher denitration efficiency.