Industrial processes rely on a specific combination of parameters and variables to ultimately deliver a quality product. The number of these factors and the intricacy of their connection to the final product varies depending on the size and complexity of the process. In all cases, however, a strong understanding of how the process and controls system respond to variations in these factors provides great benefits. An effective way to gather this information is through the use of process controls simulation.
Process controls simulation is available through a wide variety of techniques, primarily differing in the degree of specific detail they provide for the plant and process. How detailed and robust the simulation should be depends on the company's overall goals. Is comprehensive information regarding exactly how ambient temperature impacts a reaction needed? Or does the operator only need to understand what will display when alarms or interlocks are active without physically making them happen?
Simple simulations can provide simulated feedback from controlled devices (valves, motors, etc.) and simulated process variable changes in response to various triggers. Advanced, high-fidelity simulations can be tuned to mirror the process down to the smallest detail.
Process controls simulation can serve as a powerful and effective tool for operators in the following ways:
Operators are the heart of any industrial facility. Their understanding of how the plant functions and ability to react to various situations plays a vital role in keeping the facility operational. A primary benefit to process controls simulation lies in operator training.
Whether it be a newly developed facility, an expansion of an old one, or a restructuring of a controls system, process simulation provides a powerful tool in training the operators on how to manage the plant. Most simulated systems give the operators the ability to navigate and become familiar with graphics, alarm displays, and the tools available to them while operating a plant without downtime. More advanced simulations can provide dynamic information in-tune with the true detailed functionality of the facility. This is very useful when preparing operators for startups/shutdowns and how to respond to plant disturbances and emergencies.
Simulation at all levels allows for risk-free testing of the controls system. By simulating the process and controls system, the operator has the ability to thoroughly test the configuration and logic programmed for the plant without stroking a single valve. This provides the ability to test control strategies and identify potential design flaws that may lead to downtime and production loss. Speaking as an integrator, any degree of built in simulation allows for a more streamlined and effective factory acceptance testing (FAT).
For example, an increase in a tank's level after the simulated opening of the required valves adds a small detail that considerably aids in the customer's connection between the off-site program and their physical plant, and it allows them to identify any necessary changes before implementing the controls on a live system.
Process optimization, concept testing, and SOPs
Along with configuration testing, process controls simulation allows for development and validation of new standard operating procedures and experimenting on how to improve on existing ones. An improperly designed control system results in below optimal performance leading to premature wear on equipment, reduced throughput, increased energy consumption, and increased all around costs.
As the degree of sophistication increases, simulations can help locate process bottlenecks and deliver information on how modifying a feature of a process (such as an increase in cooling water flow or modifying the reflux ratio for a distillation column) impacts product yield or quality without physically making the change. Thus, high fidelity simulations also provide a means to validate new process designs or justify changing preexisting designs.
Safety, environmental, and economic
Safe operation of a facility is of upmost importance. Process controls simulation provides the ability to test both safety and process interlocks. Along with testing, simulating a process and controls system can lead to the discovery of interlocking conditions that might not have been thought of initially.
This provides a great deal of value from both a safety and economic aspect as it prevents downtime, production losses, equipment wear, and/or hazardous incidents. Fewer incidents also lead to fewer cases of associated environmental issues. In addition to preventing environmental hazards, more advanced simulations can also provide information on plant emissions to help determine methods to meet standards.
Simulations save lives
Understanding the interplay between the controls system and the process is critical to any industrial facility. Process controls simulation can aid in this development in a variety of ways. Training operators on an offline controls system can educate them and prepare them to manage the plant and disturbances. Simulation allows for thorough and efficient testing of the controls system configuration prior to implementation. It also provides a means for worry-free experimentation of operating procedures and optimization strategies.
Identifying undesirable or dangerous situations that could shut a plant down, damage equipment, and endanger people's lives is much safer on a simulated system than in a live facility. It's never too late to evaluate the benefits a simulated environment can provide.
Jeff Clark is a systems integration engineer at Cross Company Integrated Systems Group. This article originally appeared on Cross Company's blog. Cross Company Integrated Systems Group is a CFE Media content partner. Edited by Chris Vavra, production editor, CFE Media, cvavra(at)cfemedia.com.
Cross Company is a CSIA member as of 9/20/2016.
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