SCR催化器热失活数值仿真

Numerical Simulation on SCR Catalyst Thermal Inactivation

分析SCR催化器的老化形式,从催化剂颗粒直径和反应速率变化的角度对催化剂热失活特性进行研究.基于反应动力学模型,考虑SCR催化剂相对活性的降低,建立了SCR催化器热失活动力学模型.采用Fluent耦合CHEMKIN的技术路线,结合SCR催化器快速老化试验循环进行100,h的热失活模拟,建立SCR催化器二维流动模型,模拟载体入口处的温度变化,并以载体不同径向处的温度为单孔道的初始条件计算催化剂的平均粒径和相对活性变化.热失活前后催化剂的性能指标变化情况表明:NO转化效率随老化时间降低,起燃特性随老化过程明显恶化.

The aging form of SCR catalytic convertor was analyzed.Thermal inactivation characteristics were studied based on the variation of catalyst particle diameter and reaction rate.On the basis of reaction kinetic model and considering the decrease of SCR catalyst relative activity,the thermal inactivation kinetic model of SCR catalytic converter was established.Fluent coupling CHEMKIN was used to analyze the heterogeneous catalytic reactions within the channel.Combined with the thermal inactivation simulation on SCR catalytic convertr fast aging test cycle for 100,h,a two-dimensional flow model of SCR catalytic converter was established.Temperature change at the entrance was simulated,and the temperatures at different radial positions were selected as initial conditions of single channel to calculate average particle diameter and relative activity of the catalyst.Thermal inactivation before and after the change of the performance of the catalysts showed that NO conversion efficiency with the aging time was decreased,and the light-off characteristics get significantly worse with the aging process.