Simulation of automotive NH3 oxidation catalysts based on pre-computed rate data from mechanistic surface kinetics
Simulation of automotive NH3 oxidation catalysts based on pre-computed rate data from mechanistic surface kinetics
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DOI：
10.1016/j.cattod.2010.01.018
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发表时间：
2010-06
期刊：
影响因子：
5.3
通讯作者：
M. Votsmeier;A. Scheuer;A. Drochner;H. Vogel;J. Gieshoff
中科院分区：
文献类型：
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作者：
M. Votsmeier;A. Scheuer;A. Drochner;H. Vogel;J. Gieshoff
本文演示了如何使用预先计算的速率数据来实现汽车氨滑移催化剂反应器模型中机械动力学的数值有效实现。在预处理步骤中，气体种类的源项被映射为气体成分和温度的函数。从这个地图（80000个数据点），构造一个样条插值函数。样条函数近似于动力学模型的数值稳态解，平均误差小于1%。速率映射程序的应用使速度提高了大约两个数量级。样条近似是实现在一个二维模型的整体反应器通道，包括扩散在清洗层。根据通道直径和涂层厚度的不同，开放通道和涂层中的扩散限制会对nh3转化产生显著影响。令人惊讶的是，产物N2， N2O和NO的选择性对气相或大衣中的扩散效应不敏感。
This paper demonstrates how pre-computed rate data can be used to enable the numerically efficient implementation of mechanistic kinetics in a reactor model for an automotive ammonia slip catalyst. In a pre-processing step the source terms for the gas species are mapped as a function of gas composition and temperature. From this map (80,000 data points), a spline interpolation function is constructed. The spline function approximates the numerical steady state solution of the kinetic model with an average error of less than 1%. Application of the rate mapping procedure results in a speedup of about two orders of magnitude. The spline approximation is implemented in a 2-dimensional model of a monolith reactor channel that includes diffusion in the washcoat layer. Depending on the channel diameter and the washcoat thickness, diffusion limitations in the open channel and in the washcoat can have a significant influence on the NH3conversion. Surprisingly, the selectivity for the products N2, N2O and NO is not sensitive to diffusion effects in the gas phase or in the washcoat.