Some of my favorite posts are ones that come out of a string of problem-solving email messages. And so it is with today’s post.Emerson’s Mark Coughran was recently at biopharmaceutical facility that was having temperature control issues on a reactor vessel. The temperature process variable was overshooting far past the setpoint with the control loop output failing to reverse this overshoot in a timely way.
When it did finally reverse the process variable, the loop would enter into large, slow oscillations. The loop was not properly tuned for this type of integrating process.
When Mark visited the site, he used the Entech Toolkit to better understand the jacket loop process dynamic. Working with the facility staff, they discovered a problem with a steam valve that stopped at 80 degrees rotation even when the DeltaV distributed control system was giving a 100% signal to open. They also checked the responses of the other jacket valves around the reactor.
Mark and team also discovered a glycol supply pump running incorrectly. After the fixes were made to the valve and glycol system and the reactor vessel refilled, the reactor master temperature loop was tuned. The large overshoot and slow oscillations were fixed.
Mark and the Control Performance Consulting team provide this type of help at many stages in the lifecycle of a plant including factory acceptance testing (FAT), site acceptance testing (SAT), in running brownfield plants, and even on high-fidelity simulators early in the design of a project. They will even work remotely with data provided by the local business partners working with the site.
Mark also provided several recommendations on ways to improve the control strategy and with the use of higher performance control valves.
If you’ll be joining us in Denver for the October 12-16 Emerson Exchange conference, make sure to catch Mark’s presentation, Solving Pressure Control Loop Problems in Hydrocarbons Processing Plants. If you can’t be with us, make sure to join the live experts’ session on process control & optimization and get your questions in early!