3 Ways Choosing the Right Simulation Fidelity Boosts Plant Performance
By Alejandro Elizondo
When a simulation project is in its initial stages, it's vital to identify the specific problems it's expected to solve. After these objectives have been identified, the next crucial step is selecting the right fidelity for the project. The overall cost and potential benefits of the simulation depend heavily on this choice.
Some may believe that high-fidelity solutions are the best choice for all plants and needs, but that’s not always the case. Many project requirements can be met with solutions that are both faster and more cost-effective.
So, how does one choose the right simulation fidelity to meet project needs and boost plant performance? There are numerous ways to benefit from the right model, but we will focus on three key areas:
Making FAT (Factory Acceptance Testing) more robust and comprehensive
Improving efficiency during SAT (Site Acceptance Testing)
Reducing the learning curve for operators
Making FAT More Robust and Comprehensive
The Factory Acceptance Test is a critical phase in a process control project, where the final user verifies that everything is configured as expected. A simulated environment can make an FAT significantly more robust. For instance, a medium-fidelity model can be used to test a sequence where a tank recirculates its contents with a pump. If the sequence starts the pump, opens a valve but fails to set the pump speed, the simulation would immediately show that no flow is returning, revealing a missed step that might not be caught until the plant is live.
For these cases, it's important to have models with at least medium fidelity or above, as they incorporate flows, pressures, and mass conservation. This doesn't mean that a low-fidelity or tiebacks-only simulation is useless for an FAT. It can still be very helpful for checking simple interlocks and verifying that loops are configured correctly.
While a simulated environment with process modeling might increase the time required to perform an FAT, this is not a major issue. The cost of an hour spent on an FAT is significantly less than an hour of downtime during the SAT.
Improving Efficiency During SAT
As mentioned, using simulations helps uncover minor configuration errors that would otherwise only appear once the system is set up in the actual plant, complicating the startup process. The SAT involves a great deal of people, teams, and work, so every hour saved or spent has a major financial impact.
Essentially, a simulated environment’s greatest contribution to the SAT is helping to find minor errors that only a live plant, or in this case, a simulation, can reveal. However, it's important to remember that there will always be issues that can only be found once the physical plant is running, as no simulation can ever match the real plant with 100% accuracy.
Reducing the Learning Curve for Operators
Regardless of the chosen fidelity, a simulation can be a valuable tool for operators. It’s easy to forget that not everyone is familiar with a system’s interface and how objects are represented graphically. A system with just tiebacks can be useful for introducing operators to the controls, allowing them to navigate and interact with the plant's graphics.
However, if the simulated system is developed as a full-fledged Operator Training System (OTS), it can drastically reduce the time needed for an operator to learn how to manage the plant. This includes performing specific procedures, understanding what can cause a plant trip, and learning how to avoid or recover from a shutdown event. Such training can help prevent accidents and production losses.
Conclusion
Choosing the right fidelity for a simulated environment is a critical step that will significantly impact the project's profitability. It’s crucial to have a clear understanding of the priorities that the simulation needs to cover. When the core needs are clearly identified, it becomes easier to see and take advantage of all the extra benefits a well-designed simulation can provide.