Dealing with shutdown trips is no picnic for any process application, but they’re even more of a pain when your facilities are spread over 465 miles. This was the reality faced by Canadian potash producer Nutrien at its mining sites extending northwest from Saskatoon, Saskatchewan.
The company presently uses Emerson’s AMS Device Manager to coordinate its maintenance and reliability activities, including AMS Device Manager Wireless SNAP-ON and Alert Monitor SNAP-ON applications, Fisher ValveLink and ValveLink Solo applications, as well as Emerson’s AMS Trex Device Communicators. These advanced tools let Nutrien’s staff use tuning practices and control philosophies to maximize efficiencies and immediately identify savings.
However, despite these advantages, the company didn’t have a way to use AMS Device Manager and ValveLink to proactively identify failing assets at their mining facilities. More specifically, the challenges confronting Nutrien included:
- No formal, shared, site-based tracking system and database to record maintenance for more than 3,000 instrumentation assets from multiple manufacturers.
- Limited available site personnel at each potash mine.
- Insufficient training on newly installed equipment.
“Depending on the run, a failure could cost $75,000 to $100,000 USD per hour,” said Ryley Blyth, instrument asset specialist at Spartan Controls, an Emerson Impact Partner that assisted Nutrien with its project to create better visibility into pending equipment failures. “The company’s first goal was to monitor its assets to identify weak links before they could break—and even catch problems before operators could see them.”
Remote access reveals needed repairs
Blyth reported that Nutrien and Spartan started by analyzing about 300 control valve assemblies during outages at its Allan, Saskatchewan, pilot site. This included monitoring transmitters and positioners to identify device failures, and using a proactive approach to repair issues identified during testing.
“The big picture goal was to work our way up to Nutrien’s Rocanville facility because it's the largest producing mine,” said Blyth. “However, the biggest initial roadblock was the travel required to each site, involving many kilometers and many hours of travel time.” Nutrien could realize big cost savings with remote access and monitoring by an instrument asset specialist (IAS), who could correctly set device alerts in the AMS Device Manager alert Monitor SNAP-ON to focus on the most important ones, and work with onsite technicians to decide what to do with them, Blyth explained.
To establish the necessary links for remote monitoring, the partners initially implemented SpartanPRO Connect software on about 218 valves and measurement devices at Nutrien’s pilot facility, which let them access staff at the Spartan Controls Automation Centre in Calgary, Alberta, and Iris cloud-based analysis and documentation services. This enabled reports for supervisors and technicians, approval and work execution orders, and established a feedback loop with SpartanPRO for subsequent updates.
“Any special finds or gotchas can be shared among the instrument groups at each site,” explained Blyth. “This allows best practices for setting up instruments, and spreads valve assembly set up and tuning standards across all sites. Likewise, nuisance or irrelevant alerts can be eliminated by using cross-site sharing.”
Common detectable deficiencies in the valves included:
- Poor tuning,
- Friction or torque,
- Trim erosion,
- Actuator or accessory leaks,
- Low air supply pressure or volume,
- Plugging,
- Positioner or travel feedback failure,
- Incorrect bench set,
- Insufficient seat load, and
- Improper travel.
Common detectable deficiencies in the measurement devices included:
- Electronics failure,
- Sensor failure or degradation,
- Low or high temperatures,
- Sensor over-range,
- Grounding issues, and
- Process out of limits conditions.
“Using the diagnostics in ValveLink during outages or turnarounds makes it easier to predict future valve failures. The most common issue in potash mining is torque increases that can be seen in the signatures of rotary valves,” explained Blyth. “After testing and analysis, new trim can be ordered ahead of a scheduled outage and installed during planned downtime. Catching these issues early prevents problems from propagating into process controls.”
Andrew Galambos, journeyman instrument technician at Nutrien, added, “We usually have planned downtime for a day every two weeks. During that time, we can usually examine 90 to 140 valves. However, our log files were previously in Microsoft Word with entries that were typed in manually.”
More benefits, fewer shutdowns
Beyond turning up physical issues and required fixes, remote access and monitoring also enabled Nutrien’s mentorship efforts. These occurred in several onsite areas, including system maintenance, device-specific training, device configuration, alert interpretation and setup best practices. The company was also able to offer formal, in-person training in Saskatoon, which was less costly than traveling to Edmonton, Alberta.
Thanks to the success of its remote monitoring pilot, Nutrien also expanded its alert monitoring program from its initial 218 devices to more than 3,500 devices that handle temperature, pressure, flow density, level and valve control.
Remote monitoring also helped Nutrien prevent a shutdown of the alcohol injection process that keeps the natural gas control at its Rocanville site from freezing during the winter. Located between the digital valve controller (DVC) and the actuator for natural gas, the injection assembly consists of a remote-mount travel feedback isolated from the harsh, ambient environment.
“This is arguably the most critical valve at the Rocanville mine because its failure would cause a complete plant shutdown and halt all potash production,” added Blyth. “Initial diagnostics in 2019-20 showed this injection valve assembly was healthy and performing well, but diagnostics in 2021 showed signs it was leaking instrument air somewhere between the DVC and the actuator. The injector unit was disassembled, and a leak was found in its fittings, which were replaced before reassembly. Further testing showed that the leak issue was resolved and the valve was operating normally.”
Likewise, testing indicated that a brine addition assembly at Nutrien’s Allan mine had a repeatable travel shift in its performance signature, and a field inspection showed that its feedback assembly was seized and cracked. A failure like this could cut production by 459 tonnes per hour.
Riley added that remote valve monitoring has allowed many of these tasks to be digitalized, which allows Nutrien to save more time. “The operators and technicians can go through their alerts and pre-plan maintenance more quickly,” he added. “Over about six years, remote monitoring enabled Nutrien to prevent significant downtime and production losses. In fact, tracked by Iris data analytics, the company has saved about $7.6 million or 15,000 tonnes.”
