Modelling dynamic feeding in cyclic separation

Modelling of cyclic separations is extended to account for a non-instantaneous liquid feeding period succeeding the liquid flow period in established models. The inclusion of variable holdup infers inter-tray variations and time-variant behaviour. For a linear case of ammonia stripping, we employ solution methods involving state-transition matrices derived using a Peano–Baker series expansion to retain linear solution methods for determining the pseudo-steady-states. The expanded model is then utilised to evaluate the impact of prolonged feeding relative to prolonged liquid flow periods on separation performance for established simultaneous and sequential draining strategies. Accounting for the non-instantaneous behaviour showed improved agreement with experimental results and illuminated that prolonged feeding can significantly reduce the overall column separation performance. • Extend the mathematical model for cyclically operated strippers/absorbers with a dynamic feed period. • Leverage the Peano–Baker Series expansion to linearise the time-variant ode system. • Illustrate the feeding flow rate effects on the average operating point efficiency.