The flexibility of this automation system allows Synthomer engineers to easily accommodate process changes and even institute improvements between batches if necessary. Everything begins with reliable digital data received from fieldbus devices. The reactor instrumentation includes magnetic flow transmitters, vortex flow transmitters, pressure and temperature transmitters, mass flow meters, fieldbus-to-current converters, radar level transmitters, multivariable temperature transmitters and digital valve controllers. These smart devices, made by a variety of vendors, transmit highly accurate readings that enable faster response by automated controls.
The fieldbus instruments also generate useful diagnostic data on their own condition and that of the process, aiding in the troubleshooting of suspected problems in two ways:
1. Operators quickly recognize if a given device is OK — no one has to go to check it out;
2. Any problem that exists is immediately pinpointed — so the maintenance technician can be told exactly what to look for and what tools and supplies to take.
The field-generated information allows us to optimize the control system over time to improve jacket heat-up time. We now can reach the temperature set point faster so the batch gets started sooner. This has reduced dead time for recharging a reactor, even when switching products to satisfy an order.
Quality remains consistently high due to excellent batch-to-batch reproducibility with the DeltaV system. Reliable data from the fieldbus instrumentation have resulted in better flow control, affording more accurate batch charge quantities. Improved reactor temperature control further contributes to consistency. In addition, we can make changes in-house to phase logic and equipment modules for greater reliability and reproducibility across reactors.
No one wants to abort an expensive batch but if control is lost due to excessive deviation from the ideal temperature profile such action may be inevitable. Improved temperature control — a direct result of digital temperature measurement and transmission — reduces this problem. Better flow control stemming from improved instrumentation leads to more accurate additions to the reactor and quicker reactions, further decreasing the probability of an aborted batch because of inaccurate addition of ingredients.
Data from the fieldbus devices also are used in report generation, instilling confidence in managers making operational decisions.
Another beneficial technology employed from the beginning is Emerson’s AMS Suite: Intelligent Device Manager, which seamlessly integrates with the DeltaV system. This predictive maintenance software works in concert with PlantWeb architecture and fieldbus communications protocol, capturing diagnostic data generated by fieldbus devices, maintaining a device database and raising alerts to potential problems.
AMS Device Manager is always on, capturing diagnostics and keeping operators and technicians continuously informed of potentially serious conditions.
We’ve received status alerts such as “reverse flow detected,” “low cut-off active,” valve “travel out of range,” and “device needs maintenance soon.” These alerts occur frequently on the reactors, our most critical process units. Each is fieldbus-intensive, with a number of flow meters (Figure 1) and control valves. Status alerts help keep us ahead of unforeseen issues, reducing the potential for “work-offs.”
The alerts instantly bring emerging concerns to the attention of plant personnel, enabling them to obtain detailed information from devices or valves. With knowledge of what’s happening on a real-time basis, staff normally can prevent unexpected upsets and implement predictive maintenance to extend the life of the field devices.