As. Serbezov et Sv. Sotirchos, MATHEMATICAL-MODELING OF THE ADSORPTIVE SEPARATION OF MULTICOMPONENT GASEOUS-MIXTURES, Chemical Engineering Science, 52(1), 1997, pp. 79-91
A general dynamic model describing the adsorptive separation of multic
omponent gaseous mixtures is developed in this study. The dusty-gas mo
del and D'Arcy's law are used to describe the diffusive and viscous ma
ss transport in the adsorbing bed, respectively, and the local equilib
rium assumption or the linear driving force approximation are used for
the uptake rate. The versatility of the developed model is demonstrat
ed by applying it to separation of binary, ternary and quaternary mixt
ures by pressure swing adsorption (PSA). The relative importance of th
e diffusive (bulk and Knudsen) and viscous mass transport and the effe
cts of the different uptake rate representations are also investigated
. For the PSA process, it is found that viscous transport dominates in
the adsorbing bed and the inclusion of other modes of transport in th
e model equations has practically no effect on the solution. However,
for dynamic processes occurring in porous media of smaller pore sizes
(macroporous membranes, for instance) both the viscous and the diffusi
ve modes of transport must be included in the overall model to predict
the system behavior correctly. The model with only viscous transport
in bed and the linear driving force approximation for the uptake rate
is the recommended option for modeling PSA operations, provided that t
he LDF approximation is applicable, since it is easier to handle numer
ically and reduces to the equilibrium model in the limiting case of la
rge adsorption rate constants. Copyright (C) 1996 Elsevier Science Ltd