计算大Thiele模数催化剂有效因子的近似方法

Approximate Method for Determining Efficiency Factors of Catalyst Particle with Large Value Thiele Modulus

应用带大参数微分方程理论,对具有大Thiele模数多孔催化剂颗粒内的非线性扩散-反应边值问题作了近似处理,提出了计算催化剂有效因子的近似表达式。针对冪函数型和Langmuir-Hinshelwood型动力学方程,用近似表达式计算了片形、圆柱形、球形3种不同形状催化剂颗粒的有效因子。将近似表达式的计算结果与用正交配置法计算的结果比较,二者在较宽的参数范围内十分吻合。通过计算还表明,利用近似表达式计算催化剂颗粒的有效因子,具有使用简便、计算快速的优点。

Approximate treatment of nonlinear diffusion-reaction boundary value problems is concerning porous catalyst particles with large value. Thiele modulus was carried out by applying theory of ordinary differential equation with large parameter. Approximate expression for calculating efficiency factors of porous catalysts was derived. Efficiency factors of three types of catalyst particles were calculated by means of approximate expression with power law type kinetic expressions and Langmuir-Hinshelwood kinetic expressions. Results obtained by approximate expression were compared with those by orthogonal collocation method. Agreement between was satisfactory in quite a wide parameter range. Moreover, the presented method for evaluating efficiency factor was simple, rapid and effective.