Robust PID control for an industrial distillation column

State-space controllers are difficult to implement in a distributed control system. Therefore a control design based on the common PID control structures is desirable. This article presents the μ-optimal tuning of advanced PID control structures as well as a simple feedforward control design for an industrial binary high purity distillation column. The design is based on an optimization approach. The resulting controllers ensure stability and a high performance for the entire operating range of the distillation column. A summary of the practical experiences complements the theoretical results.