Effect of feed concentration in equilibrium parametric pumps

The effect of high initial feed concentration in batch equilibrium parametric pumping was experimentally investigated at different bed temperatures and cycle times. The system studied was benzene-n-hexane over a silica gel bed. It was observed that the initial feed concentration which leads to the best separation is dictated by the shape of the equilibrium isotherms of the system. An increase in the temperature difference between hot and cold cycles was shown to improve the separation because it led to a more favorable equilibrium relationship. Experiments also indicated that a long enough cycle time must be selected for true equilibrium to be established within the system, otherwise maximum separation cannot be obtained. In mathematical modeling studies the effect of nonlinearity of equilibrium isotherms at high feed concentrations was shown to be very effective for predictions of the model.