Separation of gas mixtures by pressure swing adsorption: Hierarchy of mathematical models

A hierarchy of mathematical models for the separation of a gas mixture by pressure-swing adsorption is discussed. A new method of constructing the mathematical model in which the adsorption and hydraulic calculations of the plant are accomplished concurrently is proposed. This method is based on the equation of pressure dynamics derived from the material balance for the whole adsorbent bed, which can be used to determine the time dependence of the mixture pressure in the adsorber. The method is illustrated with reference to the equilibrium and nonequilibrium isothermal model for the separation of a binary gas mixture. An algorithm of numerical calculation for the mathematical model of separation in a separate adsorber is created. The algorithm includes four possible types of flow-velocity distributions over the length of the adsorbent bed.