Dependence of diffusive permeation rates and selectivities on upstream and downstream pressures : IV. Computer simulation of nonideal systems

In previous papers we have shown that a semi-empirical thermodynamic—diffusive model appears to duplicate the behavior of the hexane/heptane/polyethylene system with regard to the effect of upstream and downstream pressure on rate and separation. In the present paper we present a numerical method for dealing with our model equations, which allows us to treat nonideal systems, and to make use of more general expressions describing the concentration dependence of diffusivity. This method is discussed in detail, and several typical simulation results are presented.