Pz. Sheng et Cav. Costa, MODIFIED LINEAR DRIVING-FORCE APPROXIMATIONS FOR CYCLIC ADSORPTION-DESORPTION PROCESSES, Chemical Engineering Science, 52(9), 1997, pp. 1493-1499
This work deals with linear driving force (LDF) approximations to the
intraparticle pore diffusion equation assuming linear equilibrium. Two
approaches are used to calculate global rate coefficients for the LDF
model: the usual way where the average intraparticle concentration is
calculated from the LDF model and a new one that uses the solution of
the diffusion equation. The cyclic steady-state solutions to various
cyclic perturbations are presented and compared for both methods. Also
the global rate coefficients for processes with half-cycles of differ
ent length subjected to square wave perturbations are presented. It is
shown that the two rate coefficients needed to represent a cycle are
practically equal. To avoid the difficulties associated with the non-u
niversality, i.e. dependence on the perturbation type, of the global r
ate coefficients, an instantaneous rate coefficient is presented, vali
d for perturbations smoother than the square wave. (C) 1997 Elsevier S
cience Ltd.