Knowledge-based control structuring of a distillation plant start-up

Abstract A process-knowledge-based control structuring method for process start-up is presented. The methodology leads to a definition of tracking tasks. The tasks contain properties to describe some sub-procedures in the whole start-up procedure. Operational safety aspects are included into the task properties. By combining the tasks, a complete procedure for closed loop start-up can be described. This method is able to handle process constraints, operational safety aspects and time-varying process characteristics. For the practical solution of this challenging set of control problems the start-up methodology is implemented using fuzzy-logic control. Experimental investigation of the closed-loop start-up of an energy integrated distillation plant revealed a significantly facilitated start-up for the operator. The start-up also demonstrated more than 25% reduction in energy expenditure and time compared to a manual implementation of the same procedure.