Case Study

Natural Gas Processing Plant Improves Safety, Production by Eliminating Nuisance Alarms and Capturing Critical Data

Advanced alarm-management system improves alarm responses and operational decision-making

Challenge

An antiquated alarm system frequently triggered nuisance alarms, and operators lacked documentation to determine how to accurately respond to them

Solutions

FactoryTalk® View SE - HMI software provides comprehensive visualization of plant operations, and more control over alarms and process variables
FactoryTalk AssetCentre software - Centralizes managing, versioning, tracking and reporting of asset information for enterprise-level insight into plant-level operations

Results

The new system gives operators information necessary to precisely respond to alarms and process abnormalities
Enterprisewide historical insight allows corporate engineers to track operating trends and identify opportunities for improvement

Nuisance alarms are more than just a pain in the ear. For process industries, they’re a leading cause of unplanned downtime. They also pose major safety risks.

That’s because operators must instantly decide how to respond. The failure to correctly address the most critical automation alarms can have catastrophic consequences, as evidenced by high-profile accidents that have heightened public attention on industrial operations worldwide.

One major North American energy-infrastructure company is investing in highly advanced alarm-management systems as part of its commitment to reduce incidents across its extensive natural gas network.

The company delivers “dry” natural gas to utility customers in several high-populated states. Its operations stretch the land and seas of North America, and include midstream gathering, processing plants and tens of thousands of miles of cross-country pipelines.

Overwhelmed by Alarms

At one of the company’s processing plants, water, impurities and nonmethane hydrocarbons are removed from the natural gas, making it safe for pipelines.

When the plant’s antiquated alarm system was installed, the “more-is-better” approach was the industry norm.

“One software application could have any number of alarms for no extra money,” explained a control specialist at the company. “At this plant, there were 1,500 alarms, many of which weren’t needed or were low priority. Plus, there was no clear documentation to help operators find the cause of alarm, often leading to guesswork.”

For instance, a pump alarm might mean gas flow was being obstructed – or maybe the sensor was just malfunctioning. Without accurate information about the true source of the problem, operators and maintenance staff had to spend precious time troubleshooting the situation.

The company wanted more real-time insight into the plant’s complex control systems to allow operators to quickly and precisely adjust critical variables, as well as improve preventive maintenance.

“Flow levels, pressure, temperature – too much of anything is not good,” the control specialist said. “Operators must be able to accurately manipulate the process to stop any abnormality. We can’t afford to rupture a pipe or crater a compressor.”

The lack of a single source for historical data prevented operators from seeing previous changes to the system that may have triggered an alarm or event.

The absence of a central repository also hampered enterprise-level access to information about the plant’s operational efficiency, and what gas-processing equipment or process changes could help increase production and safety.

Finally, clear and verifiable hindsight would be crucial in the case of a serious event.

“Any company that’s not gathering historical data in today’s high-scrutiny environment is putting themselves in a position where they can get hurt,” the control specialist said. “If an event happens, we need documentation to prove what triggered it and the sequence of events. We must be able to show we are running our plant properly, and protecting people and the environment.”

Capturing Operations Data

The company turned to Rockwell Automation to help design, engineer and deploy an alarm-management system for the processing plant to meet its goals.

“The plant already had an installed base of Rockwell Automation controls, creating the opportunity for seamless integration,” the control specialist explained. “Total cost of ownership and long-term support were also big plusses that made Rockwell Automation the best choice for the upgrade.”

The first step in the alarm-system upgrade was a comprehensive assessment of the plant’s system, including identifying all current alarms. Then a team of corporate engineers, plant control operators, IT staff and Rockwell Automation specialists turned to the rationalization phase. This involved reviewing each alarm to determine if it was necessary and assigning priorities for those that would remain in place.

“In some cases, we took alarms out, sometimes put them in,” the control specialist said. “But the absolute goal was making sure the right alarm is delivered to the operator at the right time and with the right information needed for a correct response.”

That goal was met with the installation of a new Allen-Bradley^® ControlLogix^® programmable automation controller (PAC) paired with the FactoryTalk^® View SE HMI software from Rockwell Automation. The highly available supervisory-level HMI software provides comprehensive visualization of the plant’s operations.

To capture vital historical data, the company chose the FactoryTalk AssetCentre change-management software from Rockwell Automation. The software is a centralized tool for securing, managing, versioning, tracking and reporting automation-related asset information across the entire operation. With this software, the plant now can track users’ actions in detail to review any previous process changes. Equally important, the software connects to the enterprise network, providing executive insight into the operations on a macro level.

Informing Better Decisions

The plant team is still in the process of fully implementing the new system. Meanwhile, the number of alarms at the plant has been reduced from 1,500 to around 1,000.

The plant already is reaping the benefits of getting the right information to the right person at the right time.

“We’ve eliminated the bursts of nuisance alarms that were so distracting to operators,” the control specialist said. “The new system also gives us all the information we need to determine whether an alarm is critical or lower priority."

Production has improved because operators have a more precise view of processes across the plant. Now, they can quickly and easily adjust gas-processing equipment and parameters for optimum efficiency and safety.

“If we have two pumps running and we only need one, based on the current flow of gas, we can turn the other one off and save money,” the control specialist explained. “If operators see a high-level alarm on a scrubber, they can control the variables needed to normalize production.”

With historical information at their fingertips, operators can also see the sequence of events before an alarm occurred to help understand the cause. Corporate engineers can also access that historical data to make better long-term decisions.

“They can use that data to see how the facility was running six months ago compared to today, and answer questions like, ‘Why aren’t we making as much money?’,” the control specialist said.

“The cost savings can be counted in pennies,” he added. “But our business is about pennies – lots of pennies.”

The results mentioned above are specific to this company’s use of Rockwell Automation products and services in conjunction with other products. Specific results may vary for other customers.

Allen-Bradley, ControlLogix, and FactoryTalk, are trademarks of Rockwell Automation Inc.

Published October 7, 2015

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