Modeling fixed-bed adsorption columns through orthogonal collocations on moving finite elements

An orthogonal collocation method based on moving finite elements has been developed for simulating fixed-bed adsorbers. The movement of the grid is calculated explicitly before starting the integration of the discretized equations, using the results of the Equilibrium Theory for wave transitions and the shock layer theory for shock transitions. The performance of the developed moving grid technique has been extensively compared with that of the corresponding techniques based on a fixed discretization grid. Substantial improvements both in computational time as well as in accuracy of the obtained solutions have been found in all cases. (C) 1997 Elsevier Science Ltd.