I put four controllers in a distillation column at the beginning they all work pretty well, however, after setting another controller, the control was getting worse (increasing IAE values).
For a control design of certain process you need to evaluate the degree of freedom (DOF) of the system after enlisting independent / dependent variables and then finalizing manipulated variable.
If you are performing a process simulation I recommend you to check the book Distillation Design and Control Using Aspen Simulation by William L. Luyben.