Using a digital twin enables process optimisation, better control room operator and field operator learning and retention for greater safety, reduced energy consumption, better plant and skid design, prediction of equipment failure, and root cause analysis. Just imagine what this can do for operational excellence in your plant.
By Jonas Berge, Senior Director, Emerson Automation Solutions, Singapore.
THE term digital twin is new, but the underlying concept is not. A digital twin is a digital model of a physical thing (eg: a whole plant, pump, or reservoir), and the data associated with it. There can be up to four parts to a digital twin.
All are not new and have existed individually for decades. What’s new is that the parts are now combined and used together, and the synthesis brings new exciting results. The increasing use of digitally networked sensors (fieldbus and wireless) for digital transformation and the Industrial Internet of Things (IIoT) feeds live data into the digital twin in ways not practical with 4-20 mA and on-off signals.
2D and 3D CAD drawings of the shape and form of plant structures and process equipment have been used for engineering for decades to detect pipe clashes, but are now being used in new innovative ways.
Digital Field Operator Learning
Industrial virtual reality (VR) learning is putting 3D CAD models to new use digitising learning to ensure competency and operational readiness. The 3D CAD model is imported into the 3D VR environment and enhanced with textures and actual plant equipment shapes rather than symbolic representations. Manual procedure steps are also engineered into the VR system. Thanks to the immense computing power of gaming graphic processing cards, the plant environment is rendered with a high degree of realism including depth perception, shadows and a first-person perspective that changes as you turn your head or squat down, creating a very immersive experience.
A user puts on the VR goggles and it is like walking into the real plant as it has been engineered to be a digital replica of the plant. He can practice manual tasks and various scenarios in the virtual environment until they get it right every time.
Some plants are already using VR for training. The VR environment rendered from the 3D CAD drawing can be integrated with the process simulation model. The combination of the form (plant design) model and functional (process) model together provides a highly realistic learning experience where actions like starting and stopping pumps or opening and closing valves changes the flows and pressures, just like in a real plant.
If your plant is old, designed without 3D CAD, the virtual environment for VR learning can still be created by other means. The VR environment can even be integrated with control room operator training simulators (OTS) such that a combined team of field operators and control room operators can work together just like they do in real-life. This can also form the basis of a Multi-Purpose Dynamic Simulator (MPDS).
Digital Control Room Operator Learning & Energy Management
Dynamic process simulation has also been used for control room OTS systems for years to practice and improve the competency of certain operator tasks like startups, shutdowns or recovering from plant upsets. The teacher sets up the scenario and monitors to see if the operator responds correctly and is able to handle the situation, very much like a flight simulator.
A new exciting development is that control room operator learning is now combined with field operator learning by integrating the OTS and VR systems such that control room student and field operator student can work together on tasks where such collaboration is required.
Energy management software also uses dynamic process simulation models for digital transformation of energy management practices to dynamically predict what the energy consumption should be for each energy stream, such as water, air, gas, electricity and steam or any other based on the current production rate. This is in turn used as a dynamic target for energy consumption, and an alarm is generated in real time on overconsumption – if the actual measured consumption rate exceeds the predicted value.
Digital Field Operator Rounds: Equipment Condition Monitoring
First principle models of how equipment work, along with failure mode and effect analysis-based models, embedded in easy-to-deploy and intuitive easy-to-use analytics software that predicts problems early in equipment like pumps, compressors, cooling towers, air cooled heat exchangers, blowers, and heat exchangers. By providing early and actionable information, maintenance can be scheduled before equipment fails avoiding downtime. At the same time, unnecessarily frequent routine inspections are avoided.
Equipment performance monitoring software uses ASME performance test code-compliant first principle thermodynamic models, equipment curves, and design data to determine the energy efficiency of equipment like pumps, compressors, and heat exchangers. An alarm is triggered when equipment is underperforming. This makes it possible to determine when the equipment should be overhauled to reinstate the performance of underperforming equipment, including when to clean a heat exchanger.
For instance, a pump digital twin tells you which of two pumps in an A-B standby arrangement runs more efficiently so you can use it while the other is overhauled. The use of digital networking protocols allows more sensors to be deployed such that the measurements required for performance monitoring can easily be brought in, further enabling digital transformation of maintenance practices.
Data from the entire lifecycle of each piece of equipment, starting from the factory, possibly including a “birth certificate” such as the original valve signature in the case of a control valve, followed by maintenance history and operation (usage) history records until the end of life, can be recorded in a database. This may include an event log and audit trail of calibration and configuration changes performed, depending on the type of equipment or device. That is, the historical records grow continuously. Digital maintenance logs and audit trails are further examples of how digital transformation has enhanced record keeping.
The digital maintenance history and operation (usage) history records along with event logs and audit trails of calibration, configuration changes performed, may be used for root cause investigation to understand the events that led up to some problem with the equipment, be it related to maintenance, operation, or perhaps configuration or something else, in order to change practices so that it doesn’t happen again.
Records like maintenance history from a computerised maintenance management software can be made easily accessible by combining it with RFID tags to associate the equipment with its maintenance records based on its unique ID.
Bits vs Atoms
The future is digital and increasingly wireless. A digital twin uses digital bits to mimic the physical world. The digital model and digital documentation concept of digital twins are not new, but the pieces of information are now being used together in new ways. Thanks to digital networking, richer data, validated by digital twins, is being generated by new innovative sensors with new functionality. Digital twins are an important part of plant modernisations geared toward digital transformation and enabling IIoT, and for new plants being built.
To learn more, visit the Emerson booth at the Industrial Transformation ASIA-PACIFIC (ITAP) exhibition at the Singapore EXPO Convention and Exhibition Centre in Singapore, October 16-18, 2018.