Implementation of advanced control in the process industry without the use of MPC

In process industry, such as chemical, pulp and paper or petrochemical industry there are plenty of processes that require multivariable control. Classical control structures that handle this, for example cascade control, feedforward, ratio control, and parallel control have been used at least since the 1930s. Today, much focus in academia is on model predictive control (MPC). In this paper we discuss the comparative advantages and disadvantages of classical control structures and MPC. We also briefly discuss some related topics in plant-wide control.