Advanced controller design for a distillation column

Abstract

This paper considers the design of an advanced (relative to conventionally tuned multiloop PI control) control scheme for an industrial Cj-splitter column using a range of recently proposed analytic tools. Due to product specifications, this column must be kept under tight control despite the effects of large disturbances and slow system response. Model predictive control was shown to provide a substantial improvement over a conventionally tuned multiloop controller but required a level of computation beyond that possible in a basic distributed control system. Controlled column behaviour comparable with that possible with model predictive control was shown to be achievable using a multiloop controller specifically tuned so as to incorporate disturbance rejection capabilities. The value of such controller design tools and their ready implementation within commercial software (here Matlab) should see their more widespread acceptance and use by the industrial control community.