An industrial experience with product quality control in semi-batch processes

Two practical approaches to the control of final product quality in semi-batch reactors are illustrated with an industrial experience. The first is an orthodox approach to the control of final quality which is achieved through a high degree of automation of all the reactor charging operations, good temperature and pressure control, and sequence of steps implemented throughout the course of the batch. The second approach to the control of final quality is to use mid-course correction policies. Both approaches to the control of final quality are illustrated with an industrial example. Through our experience with this example, the first approach, although very basic, is shown to be very important to reduce the variability in the final product quality. The second approach is useful to compensate for the new disturbances that are affecting the batch being run at the current time. Good practice is that mid-point control policies should be used after this basic automation step has been implemented as efficiently as possible.