With the electrical network model and object-oriented programming technique, a pressure swing adsorption (PSA) system may be decomposed to four objects: adsorbent column, tank, pressure source, and pipeline. Various flowsheets and operating patterns of PSA may be constructed with different combinations of objects and their topology. The objects are represented by class inheritance and encapsulation. The classes encapsulate the methods of setting up and solving the state equations according to the topological constraints and elemental constraints of resistor, capacitor, inductor and voltage and current sources. A PSA flowsheet may be represented with a heterogeneous list that creates the instances of the classes. The state equations are solved numerically on the basis of the polymorphic mechanism via virtual member functions in C + +. A four-bed PSA process, consisting of four adsorbent columns, eight tanks, two constant pressure sources, four variable pressure sources and 30 pipelines, are simulated with the electrical network model. The simulated results agree well with the experimental data, and only 7-20 outer cyclic iterations are required to reach the cyclic steady state. The effect of the dead volume and fluid resistances in pipelines on operating results is examined. Optimal searching for the valve coefficients and operating time can suggest the corresponding suitable values to increase the experimental recovery. (c) 2005 Elsevier Ltd. All rights reserved.