SCR催化剂内流动与反应过程的研究

Investigation of flow and reaction coupled process in SCR catalyst

针对V2 O5／TiO2催化剂建立了三维单孔道模型，基于Eley－Rideal动力学机制，模拟了单孔道内的流动及NOx 在催化剂表面的反应情况．经模拟结果与实验结果对比，证明了模型的合理性．研究表明：随着Re的增大脱硝效率逐渐降低；模拟温度在523～723 K时，反应物NO的转化率随温度先升高后降低；根据NO的转化率及NH3的逃逸率综合考虑NH3／NO摩尔比应该控制在0.9～1.2之间；在温度为598 K， Re 为600， NH3／NO 摩尔比为1时， NO 的转化率最高可达到97．18％；反应物的浓度沿孔道方向先快速下降后平缓下降，在单孔道长度为1000 mm的模型中，在离入口处600 mm时NO脱除率可达到总脱除率的91.2％．模拟结果可为SCR催化剂的运行优化提供重要依据．

Based on Eley-Rideal kinetic mechanism, a 3D single channel mathematical model for honeycomb catalyst （ V2 O5/TiO2 ） was established.Flow and reaction coupled process in the catalyst was investigated.The simulation results coincide with the experimental results in literatures, which proves the reliability of the model. The simulation results show that with the increase of Re number, the efficiency of de-NOx gradually decreases. Between 523~723 K, NO conversion rates rise firstly, and then drop.Considering the conversion rates of NO and the escape rates of NH3 , the NH3/NO ratio should be controlled between 0.9~1.2 .According to the calcu-lation results, the de-NOx efficiency can reach 97.18%at 598 K, a Re number of 600 and a NH3/NO molar rati-o of 1.The concentrations of reactants along the axial direction decline sharply and then level off.At a distance of 600 mm from the entrance, the NO removal rate reached 91%of the total one in the 1000 mm length model. The simulation results can provide an important basis for the operation optimization of SCR catalysts.