Model Predictive Control of Batch Temperature

Overview:

Control modules used for critical phases of reactor operation such as heating, cooling and reacting can be optimized using advanced process control technology to reduce batch cycle time. Temperature control of batch reactors is difficult for conventional proportional-Integral-Derivative (PID) controllers due to the open loop instability of these processes coupled with the long time delays and large time constants. These dynamics are present on various reactor designs involving heating or cooling with jackets, internal coils, or recirculation loops through external heat exchangers. Model Predictive Control (MPC) provides an alternative to PID for use in these control modules to dramatically improve temperature set point tracking, improve product consistency, and reduce batch cycle time. This paper describes the design of an MPC controller that is built to specifically handle the dynamics found on batch reactors as well as the large process disturbances that occur due to exothermic reactions. The results of an application example will be discussed.