A method of controlling a distillation column having control valves to control both reflux and the vapor rate within the column. In accordance with the present invention, a temperature sensed in a top section of the column is magnified and utilized within the model predictive controller so that control is more aggressive as temperatures increase beyond a threshold temperature. Additionally, in the distillation column, or in fact in any other system in which two or more manipulated variables control two or more common controlled variables, special modeling techniques are utilized to make controller tuning easier to accomplish. In such modeling techniques, each manipulated variable is assumed to be able to have an effect on a controlled variable by a single step response model and other step response models are utilized so that the other manipulated variable(s) that also would have an effect on the same controlled variable are taken into account by the controller as feed forward variables.