Stability analysis of a pressure swing adsorption process

Hydrodynamic stability during advection combined with diffusion and adsorpt ion of a binary gas mixture in porous media is considered in this work. The general framework is that of pressure swing adsorption (PSA) on beds of ze olite beads. The dispersion/adsorption problem is studied at Darcy's scale on a 1D porous column from a numerical point of view while complete time-pe riodic cycles are considered. The regular solution of the problem is first sought using a finite volume scheme and stability analysis is performed on this time-dependent solution. While instability evidence is shown on a dire ct 2D numerical simulation of the problem with pressure and concentration d isturbances at the entrance of the column, the stability analysis is carrie d out in 1D by making use of the linear amplitude equation method. Results clearly show the stability conditions which are quite different depending o n whether pressure or concentration disturbances are considered as initial conditions or maintained as boundary conditions at column entrance. (C) 200 1 Elsevier Science Ltd. All rights reserved.