The Integration of Control and Optimization in Process Control

Okko Bosgra

In modern chemical process industries, global competition requires to produce chemical products satisfying tight customer-specified quality properties. This requires a production management where one continuous plant is used to produce many different products or product grades. Frequent grade changes are a consequence and hence there is an economic incentive in finding economically-optimal production schedules and grade change policies. Here the role of control engineering becomes of paramount importance. Only under tight feedback control it is safe to have frequent grade changes. An economic performance criterion for realizing a grade change within equipment-specified constraints under normal plant disturbances is the control challenge. The talk will discuss these issues and will show how a flexible scheduling implementation can be combined with real-time integrated feed forward and feedback control performing an economically optimal operation of the plant under grade changes in continuous production. Some aspects of control solutions will be shown for a high-density polymerization plant.