Digital-based protocols, such as those used by fieldbus technology, are finding their way into a wider range of plant automation technologies. Read about the Fieldbus Foundation and how its technology can be implemented at your plant.
It has been nearly a decade since the Instrumentation, Systems and Automation Society (ISA) introduced S88, its first standard for batch control systems. Its still integral in optimizing operations today.
Install a flow meter in the recycle, cascade the flow set point with a pressure control loop. With proper tuning, the valve characteristics are lost in the flow control loop, which should be tuned fast with PI.