CO在成型催化剂上脱除NO_(x)的反应动力学模型

Kinetic model of NO_(x) removal by CO onto forming catalysts

采用实验和模拟相结合的方法研究了NO_(x)在固定床反应器中的吸附还原过程。选取商业常用的堇青石和TiO_(2)为主要的成型催化剂基体材料,以铜铁铈复合型金属氧化物为活性成分,制备了蜂窝成型催化剂,对蜂窝催化剂的吸附性能和脱硝还原活性进行测定。建立了固定床反应器中CO脱除NO_(x)的反应动力学模型,由于CO法脱硝反应的解耦分解,脱硝反应模型也由吸附模型和还原模型组成。吸附模型由固相和气相的微分质量平衡方程建立,还原模型由一组微分方程组成。通过固定床NO_(x)吸附曲线和不同温度下NO_(x)的转化率对模型中的关键参数进行了拟合,得到了CO在成型催化剂上脱除NO_(x)的反应动力学模型,该模型与实验数据吻合较好。在此基础上,模拟了其他条件下吸附过程的穿透曲线和还原反应的转化率。此模型能较好地揭示CO在蜂窝催化剂上还原NO_(x)的反应动力学,为CO法成型催化剂脱除NO_(x)的实验或者工程提供理论指导。

The adsorption and reduction process of NO_(x) in a fixed bed reactor was studied by combining experiment and simulation.Commercial cordierite and TiO_(2) were selected as the main forming catalyst matrix materials,and copper,iron,cerium compound metal oxide was used as the active component to prepare the honeycomb forming catalyst.The adsorption performance and reduction activity of the honeycomb catalyst were measured.The reaction kinetics model of NO_(x) removal by CO in fixed bed reactor was established.Due to the decoupling decomposition of CO reduction,the reaction model of removal was also composed of adsorption model and reduction model.The adsorption model is established by the differential mass balance equation of solid and gas phases,and the reduction model is composed of a set of differential equations.The key parameters of the model were fitted by the NO_(x) adsorption curves of fixed bed and the conversion rates of NO_(x) at different temperatures.The reaction kinetics model of CO removal of NO_(x) on the forming catalyst was obtained.The model was in good agreement with the experimental data.On this basis,the penetration curve of adsorption process and the conversion rate of reduction reaction under other conditions were simulated.This model can better reveal the reaction kinetics of NO_(x) reduction by CO on honeycomb catalyst,and provide theoretical guidance for experiments or engineering.