PID TUNING FOR POLYMER PLANTS
Application of PiControl Solutions technology to polymer plants will improve plant-wide key performance indicators and accrue the following tangible and monetary benefits:
- Production Rate Control and Maximization
PiControl software can be used to control production tightly at a given target. The technology also provides the capability to automatically maximize the production rate subject to any process, economic or equipment constraint. The technology includes methodology for identifying closed loop dynamics between the catalyst feed with production rate and all relevant important constraints that need to be considered. The controller determines the optimal path to move as fast (but in a stable manner) to the desired (target) production rate while satisfying the constraints. PiControl also provides specialized control software product for handling process non-linearity. The internal controller parameters are automatically adjusted based on process non-linearity, completely transparent to the operator.
- Optimal Temperature and Pressure Control
Pitops (Process Identification and Controller Tuning Optimizer Simulator) can identify multivariable closed-loop process dynamics and then determines the optimal tuning parameters to control the reactor temperature and pressure optimally with minimal oscillations. Use of this technology has resulted in truly spectacular and totally unprecedented results, proven in large commercial polymer plants.
- Optimal Composition Cascade Control
Pitops software optimally tunes all the primary and secondary loops required for closed-loop composition control. Stability and improvement in the control quality of these loops in turn improves the control quality of other loops – temperature, pressure and quality and has a beneficial impact on the overall process which in turn improves overall plant profits.
- Online Oscillation Detection and Adaptive Control PiControl software can detect oscillations in a real-time online manner. Detecting oscillations in chemical processes is often rendered difficult because of varying levels of random noise and process drift. The proprietary TAD (True Amplitude Detection) algorithm unambiguously and precisely detects real oscillations without ever getting confused by noisy squiggles that make other technologies far less reliable and usable. This distinguishing control technology allows us to provide genuine adaptive control automatically and reliably and helps to reduce or dampen oscillations that can easily develop in many polymer processes.
- Pressure Setpoint Optimization
PiControl online optimization software determines the optimal component partial pressures for key components in gas phase polymer reactors. This enables the plant to optimize raw material losses in the flare/recovery systems while improving catalyst consumption efficiency.
- Daily Controller Quality Performance Monitoring and Reporting
Apromon (Advanced Process Monitoring) software product monitors all of the important PID controllers, cascade PIDs, constraint override type PIDs, low/high selector type PIDs and also certain model-based, custom or advanced controllers. Every day, Apromon generates a report on all the controllers showing 25 different control criteria.
In addition to these criteria, inside the report, every controller tag is assigned a grade from 0 (worst performance) to 100 (best performance). There is also a custom diagnostic message generated for all controller tags. A sample message is: TC101: Master controller is too aggressive and slave tuning is sluggish on proportional, excessive control valve movement. The grade, diagnostic, and message assists the plants control engineer or technician to focus on the malfunctioning controllers in the whole plant. The end result is improved control quality and timely proactive fixing of control problems.