EXTENSION OF THE LINEAR DRIVING-FORCE DUSTY GAS-MODEL APPROXIMATION TO INCLUDE SURFACE OR MICROPORE DIFFUSION

This paper presents linear driving force approximations for the dusty gas model in a bisolute system obeying linear or Langmuir isotherms, i n two situations: when there is a non-negligible surface flux in paral lel with the diffusive and convective fluxes; and when there is a micr opore resistance to mass transfer in series. The approximations were d eveloped using a semi-empirical procedure that starts with the particl e response to a square wave perturbation considering a simple diffusio n/convection mechanism, and proceeds by consecutive corrections to thi s basic result. These corrections are obtained using superposition, si milarity and pattern recognition. The approximations are good (average quadratic error less than or equal to 10%) when representing the syst em cyclic steady state, whether the perturbations are sharp or smooth. Copyright (C) 1996 Elsevier Science Ltd