SEMIANALYTICAL SOLUTION FOR MULTICOMPONENT PRESSURE SWING ADSORPTION

A theoretical study of multicomponent pressure swing adsorption (PSA) in which the system is considered to be one-dimensional, isothermal, l ocally at equilibrium with linear adsorption isotherms, and is conside red to have negligible diffusion effects and axial total pressure vari ation is presented in this paper. The resulting mathematical model for multicomponent PSA is a set of first-order quasilinear hyperbolic par tial differential equations. The similarities between this model and t he model for multicomponent elution chromatography are used to define regions of constant state in the physical plane of time and distance a nd to obtain the solution in these regions semianalyticaly. Simple rel ations in terms of algebraic and ordinary differential equations which provide quick and simple estimation of the maximum product purity, ma ximum productivity, and maximum feed and purge times for PSA processes with an arbitrary number of components are derived. The application o f the theory is illustrated by the construction of solutions for a fou r-step PSA process. (C) 1998 Elsevier Science Ltd. All rights reserved .