Applications of high-order approximate models for unsteady-state diffusion and reaction in a catalyst

作者：Cho Wonhui; Lee Jietae^*

来源：Korean Journal of Chemical Engineering, 2013, 30(3): 580-586.

DOI：10.1007/s11814-012-0188-8

• Adsorption Dynamics
• Pore Diffusion Model
• Fractional Order System
• Linear Driving Force Model
• Convolution

The partial differential equation for unsteady-state diffusion, adsorption and a first-order reaction in a catalyst is often approximated to ordinary differential equations for reduced computational loads. Very high-order models obtained by the continued fraction expansion method are accurate for a wide range of the Thiele modulus and the changing frequency of surface concentration. In addition, they are numerically well-conditioned. However, due to their high dimensionalities, they will not have merits over other low-order models. Here, high-order models based on the continued fraction expansion method are shown to be used to obtain various practical models. With the Taylor series obtained from high-order models, Pade approximations are easily obtained regardless of the Thiele modulus and the shape of catalyst. Low-order models by applying the balanced truncation method to a high-order model can also be obtained, providing better approximations than the well-known Pade models.

• 出版日期2013-3