Amm. Mendes et al., LINEAR DRIVING-FORCE APPROXIMATION FOR ISOTHERMAL NON-ISOBARIC DIFFUSION CONVECTION WITH BINARY LANGMUIR ADSORPTION/, Gas separation & purification, 9(4), 1995, pp. 259-270
This paper presents several reduced models for the intraparticle diffu
sion/convection mechanisms in spherical homoporous particles under iso
thermal conditions. These semiempirical linear driving force approxima
tions were developed for the cyclic steady state that is attained when
a cyclic concentration and/or total pressure perturbation is imposed
at the particle surface. The models are applicable to linear systems o
r those obeying bicomponent Langmuir isotherms. The linear driving for
ce approximations have two or three parameters for each component and
are presented for the following cases: Knudsen diffusion, molecular di
ffusion, molecular plus Knudsen diffusion in series, viscous flow, and
also for both diffusion mechanisms in series, in parallel with the co
nvective flow, as in the dusty gas model. Comparison between the resul
ts obtained with these approximations and with the complete models sho
ws that on average the relative quadratic error is approximate to 10%
for non-smooth and 5% for smoother perturbations.