I am trying to model a Benzene recovery process by extractive distillation in Aspen plus. The calculation type chosen for the radfrac column is 'equilibrium' with the tray efficiency of 75%. i could obtain the desired results. I tried to change the tray efficieny to 30%, but there was no significant change in the overall results. Why is it so? Can someone please explain me why the effect of changing tray efficiency was not observed in the recovery of Benzene?