Controller design for the heating system of a semibatch distillation column

For the operation of distillation columns a controller for the heat supply to the re-boiler is needed. Based upon a model a linear multi-input multi-output (MIMO) controller for the heating system of a pilot plant column is designed which provides good set-point tracking and disturbance rejection as well as robustness to plant model mismatch. A nonlinear model was used to investigate the fundamental system behaviour while a linear model with two inputs and two outputs was used for control design purposes. Due to the different dynamics of the subsystems two single input single output (SISO) controllers are sequentially designed. The closed-loop behaviour is investigated for both the nonlinear model and the real pilot plant.