Nova Chemicals’ Corunna site in Ontario, Canada is a refinery and petrochemical complex that supplies 30 to 40 percent of Canada’s total requirements for petrochemicals. The company initially purchased Emerson Process Management’s AMS Device Manager software to manage 100 tags in its control system in 1999. Over the years, the number of tags managed by AMS has increased to 4,000. According to Ralph Whitney, head of instrument/electrical reliability at Nova Chemicals, this tag count will soon increase to 5,000.
Recounting Nova’s progressive use of the AMS Device Manager, Whitney says the project started with the Rosemount 848T temperature transmitter connected to DeltaV via Foundation Fieldbus to AMS Device Manager to diagnose thermocouple issues and increase the reliability of a key compressor. In 2005, AMS was integrated with the plant’s DCS via a HART multiplexer. That’s when the tag count really exploded—and so did the alerts.
“We wanted AMS to deal with all the nuisance alarms operators had to deal with when the system was expanded to 3,000 tags,” said Whitney, who added that you have to set alerts on devices correctly to mitigate this issue. “You can't just turn them on in default mode or you’ll be overloaded with alarms.”
Emerson Process Management Implementation Services helped Nova Chemicals address the abundance of alarms using AMS to categorize the alarms A, B, C and D alarms range from “critical and requiring intervention” to information-only alerts.
“Each device has its own template in AMS and we choose which alerts we need to use for each device,” said Blair Fraser, lead process automation specialist for lifecycle services for Lakeside Process Controls, the Emerson Process Management Services provider for Nova Chemicals.
Before Nova Chemicals addressed the issue, the 3,000 devices on the system were creating 20,000 alerts. “With AMS Device Manager, we now just monitor around 50 alerts from these 3,000 devices,” said Whitney. “We narrowed it down to just get notifications on alerts that can cause failure, and that require a technician’s response.”
Whitney added that, beyond alarm management, AMS has been critical to Nova Chemicals’ plant turnaround planning and execution process because it can “tell us what instruments or valves need attention. The alert monitor in AMS is used to identify devices that need repair,” he said.
“As part of the most recent turnaround, we scanned for valve signatures and identified that 84 of 88 did not require removal. This saved $107,000,” Whitney said. “We used to take all the valves out to assess them as part of our turnaround process every five years.”
Beyond the man-hour and direct cost savings delivered by the AMS valve assessment, the AMS Device Manager is also used by Nova Chemicals to verify and simulate signals to its DCS and PLCs, troubleshoot guided wave radar devices, and verify temperature transmitter failures on interlocks.
