Just about all plants have a few “blind spots” where instrumentation has not been installed due to cost, installation difficulty, or other hurdle. ModelingAndControl.com’s Greg McMillan is giving an AIChE virtual local section presentation, Wireless Measurement and Control-Opportunities for Diagnostics, Process Metrics, Inferential Measurements, and Eliminating Oscillations on August 25th at 10am EDT/ 14:00 UTC.
The abstract for this WebEx presentation is [hyperlink added]:
Wireless measurements reduce wiring installation and maintenance costs and eliminate electrical noise and ground loops. The portability of wireless transmitters offers opportunities to troubleshoot locations in the process with abnormal operations and to demonstrate process control improvements and online process and equipment metrics such as yield, reaction rate, energy use, and fouling. The PIDPlus in DeltaV v11 has enhancements that deliver the following benefits in control applications:
- Inherent prevention of process oscillations from update delay, sensitivity limits, and failures that are observed when a traditional PID is used for wireless measurements, analyzers, and sticky valves.
- Reduction of the integrated absolute error (total error) and peak error (maximum error) for unmeasured load disturbances when the update time is significant compared to the process response time. For set point changes, the overshoot, rise time (time to reach setpoint), and settling time are decreased.
- Standard tuning for maximum load rejection may be applied independent of the measurement update time whereas the traditional PID requires special detuning to stabilize the loop for large update times.
Greg was kind enough to send me a preview of his presentation. Here are a few highlights I gleaned. Opportunities for wireless temperature measurement include:
- Finding a distillation column control point with the largest and most symmetrical change in temperature with reflux/feed or steam/feed ratio
- Heat transfer coefficient metrics (fouling and frosting)
- Combined with differential pressure measurement for packed absorber and distillation column hot spot and flow distribution analysis and control
- Combined with flow measurement for control of reaction rate and crystallization rate from heat transfer (BTU/hr measurement and control)
- Combined with differential pressures for fluidized bed reactor hot spot and flow distribution analysis and control
- Combined with flow measurement to debottleneck coolant systems
He shares additional opportunities with wireless pressure measurement, pH, and conductivity measurement. The presentation is filled with examples where these wireless measurements have been applied and how the advanced PID responds to input from wireless devices.