PID Tuning For Polymer Plants
PiControl has developed an advanced process control suite comprising of several proprietary advanced control schemes for polymer processes ranging from polyethylene, polypropylene, elastomers, polyester to styrene. These proven solutions have been packaged and ready to be tailored to your plant needs. Find out how we can help with 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:
- Polymer Property Online Predictive Models
PiControl™’s PiConX control software product, calculates properties – Melt Index, Density and/or MFR. The calculations run every minute and are displayed on the DCS screen. They can also be trended for displaying historical values. As soon as new lab values are detected, the model predictions get auto-updated to account for the error between the lab and the model values corresponding to the time of lab sample collection. PiControl applies powerful automation and programming internally to provide the best, most user-friendly operator interface.
- Steady State Polymer Property Control
By using the predictive models for MI, density and/or MFR, PiControl implements powerful closed-loop controllers for controlling MI, density and/or MFR by automatically manipulating the appropriate raw material feeds. Control action is smooth and optimized for tight and stable control.
- Transition Sequence Control
PiControl uses its revolutionary BLAST technology (Ballistic Loop Anchored Sequence Trajectory) to provide powerful automatic controls for product transitions. The operator just specifies the new grade number or name and PiControls PiConX control software product automatically transitions from the current MI, density and/or MFR to the new targets. PiControls technology is totally unique and completely unparalleled and unprecedented in terms of simplicity, ease of operator use, understanding, maintenance and intervention.
- 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
PiControl uses PitopsOPC (Process Identification and Controller Tuning Optimizer Simulator), to 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
PiControl software optimally tunes all the primary and secondary loops required for closed-loop composition control using the PitopsOPC. 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 uses Tadpole control software product to 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. Unlike competitor software, PiControl uses its proprietary TAD (True Amplitude Detection) algorithm to unambiguously and precisely detect real oscillations without ever getting confused by noisy squiggles that make other technologies far less reliable and usable. This distinguishing control technology allows PiControl 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 uses TurboMax online optimization software to determine 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. TurboMax is a general purpose non-linear constrained reduced gradient optimizer and may be used for any other optimization applications specific to any plants or process needs.
- Online Dew-Point and Enthalpy Calculations
PiControl provides software for online dewpoint calculations, enthalpy calculations, heat-balance-or-mass-balance-based production rate calculations or any thermodynamic and kinetic calculations as needed by the plant or process.
- Finishing/Compounding Train Advanced Control
PiControl provides consulting services and also OPC or DCS resident control software to provide online rate maximizing and constraint pushing type advanced control on the finishing/compounding trains. This section of the plant is full of mechanical equipment – transfer line blowers, solids transfer, extrusion equipment, pelletizers, cutters etc. PiControl carefully examines the whole process and comes up with a custom design to stabilize, optimize the operation along with train throughput maximization.
- Reactor to Extruder Throughput Integration
The upstream polymer reactor and the downstream extruder train are like two different plants. Matching the production rate from the reactor and the extruders can be challenging and if not done well, can result in lower efficiency (lost production). PiControl provides integration between the reactor and extruder train which improves operational efficiency which in turn translates to higher profits.
- Laboratory Information Management System
PiControl’s PiLims OPC-based software product allows the laboratory technician to enter lab data onto a Server-type computer and then the data gets automatically transferred to the DCS using OPC protocol.
The PiLims system provides label printing option, comments/notes recording to enter any useful operator/technician notes highlighting the laboratory samples. The lab data can also be trended to allow inspection of historical data. This feature is useful for laboratory data analysis, management and process troubleshooting.
- Daily Controller Quality Performance Monitoring and Reporting
PiControl™ 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.
- Advanced Plant-Wide Data Trending Historian
PiControl installs a plant-wide historical data trending software product. This provides data trending of historical data that can be saved for several years. Engineers, operators, supervisors and managers can examine past data on any tag. Access is both local and remote; thus plant personnel can access data trends from home, hotel or remote location while not at the plant. The package also provides capability to develop user-friendly screens with bars, charts, customized displays with and without animations and live online change of shapes or colors to alert process status. DCS graphics can also be mimicked on the computer display created by PiControls historian package.
- Fast Data Monitoring and Shutdown Debugging
Using the PiLogger OPC-based software product, PiControl provides debugging and root-cause investigation of equipment shutdowns and plant/process operating problems. The PiLogger product can scan tags at the rate of milliseconds and keep a recent history of data on critical tags. The most recent 2-3 days of data is always saved in history in the form of a circular file. After an incident has occurred, fast-scanned data with 2-3 days of history provides invaluable insights into trying to analyze the problem. PiLogger also helps to identify the first-out which tells the first and foremost event that caused the process problem or equipment shutdown.
- Process Engineering Online Analysis Tools
Many process engineers, operations experts and research engineers develop and implement various Excel-based spreadsheets to calculate important process calculations. PiControl provides consulting services to convert all custom applications into online OPC-based software that reads live data directly from any DCS/PLC or external server using OPC. All calculations, rigorous, complex, iterative etc. can be implemented on a server. Calculations can be displayed on the server or may be displayed on a DCS screen or a PLC-PC HMI screen.
- Expert System Operator Advisory
Many new plants are being built today. Many new and inexperienced technicians, operators and engineers enter the control rooms and plants every year. PiControl specializes in capturing technical knowledge and wisdom from experienced personnel and then programming a custom Expert System Rule-Based Advisory called PiConX. PiConX can be programmed with sophisticated and smart rules that will display special alerts to the operator when the conditions triggering that rule are satisfied. A sample alert is as follows: Compresor A125 outlet temperature is high for over 15 min while ambient temperature is low, rate is low; check compressor local gauges. Any complex/smart message needing timers, multiple nested logic and backward logic propagation can be implemented. PiConX helps to capture the knowledge, wisdom and skills of experienced operators, technicians and engineers and then save it permanently for online use and benefits of new personnel. Loss of people through retirement and promotions does not lead to a total loss of skills and knowledge of those individuals.
- Onsite Operator, Technician and Control Engineer Training
PiControl engineers are skilled in the area of process control, advanced process control, process engineering, plant startup, troubleshooting and possess years of hands-on industry and software experience. PiControl conducts world-class renowned technical training on process control and other technical topics. Training is conducted on a regular basis in several countries and also can be conducted for clients at their plant sites or office locations.
- Remote Technical Process Control Support
PiControl can assist any client in any country remotely on any process control, DCS, startup problem. PiControl can access remote clients plant/process data through its remote monitoring and support system architecture. The plant has the option of showing all data to PiControl for help and troubleshooting. Or, if the plant does not want to allow outside personnel access to raw data, PiControls Apromon product provides the capability for displaying only the performance criteria on critical controllers. In other words, PiControl support engineers will not have access to the plants raw data but only see the criteria and diagnostics for each and every controller at the plant. With this information, PiControl can provide skilled troubleshooting guidance and help to the plant engineers. For example, the PiControl engineers will not know that the temperature setpoint is (say) 195°C but will just know that the control valve is sticking or the tuning is too aggressive, or there is some other problem. This methodology is a unique PiControl development and is a first of a kind in the whole world.
NOVOLEN Process (PP)