The monothermal NH3-H-2 chemical exchange process, operating at low temperature and high pressures, is simulated by considering nonideal behavior of both phases and multicomponent mass transfer at the gas-liquid interface. The hydrodynamics of special ejector tube tray is incorporated in the simulation and validated against actual operating plant data. The column operation is simulated with respect to process parameters to determine the optimum operating window for the column. A higher temperature operation near 270K has been suggested for better performance of the column. The multicomponent effect is not prominent in the first tower operated at 248 K and 20 MPa but is significant in the second tower operated at 270K and 10MPa. In the overall operation, the multicomponent effect cannot be neglected. (c) 2007 Published by Elsevier Ltd.