Alarms in the process are a normal part of life for plant operators. But, when improperly designed and implemented, they can be more of a nuisance, and potentially mask abnormal situations when they come flooding in.Emerson’s Marcelo Carugo shared an article with me that was published several years ago in Hydrocarbon Engineering magazine.
The article, No Cause for Alarm, highlights the journey of an Ergon refinery from too many alarms to a more optimized level.
The article opens noting the prior state before an initiative was undertaken to address the large number of alarms occurring regularly. These included:
- False alarms that did not indicate actual process problems.
- Alarm flooding upon process upsets.
- Excessive unresolved alarm issues.
- Alarm issues not prioritised.
- Lack of operator confidence in alarm information.
The refinery had multiple control systems with the newest one being a DeltaV distributed control system.
After an attempted to manage the alarms in a manual fashion analyzing them one-by-one, this approach proved to be:
…overwhelming for plant staff, so the next step was to investigate alarm management software that automated these tasks.
The refinery team identified their criteria for this alarm management software.
Minimising the time required for plant personnel to implement and operate the alarm management system would be a key to success, and these time requirements would be primarily dependent on two factors. First, the alarm management software had to be easy to install and operate. Second, the software had to integrate with existing automation system with minimal effort.
The team landed on the DeltaV Analyze software application which best fit their requirements. They shared several examples of how this software helped to reduce the quantity and improve the quality of the alarms.
…one transmitter was generating approximately 100 alarms per hour, flooding the operators with information. The problem found was not an actual alarm condition, but static in the connection between the transmitter and the automation system. The problem was quickly remedied, eliminating a significant source of nuisance alarms.
Through the alarm statistics provided by the DeltaV Analyze software, other issues found and fixed included wiring problems, improper loop tuning, and improper alarm limit settings.
The software also helped organize the alarms:
…grouping alarms with associated equipment or processes. As is common with many process plants, the main items of equipment, such as compressors and pumps, generated multiple alarms upon failure.
The alarm grouping function allowed group of these multiple alarms into one overall trouble alarm for a specific area, a procedure that is expected to greatly reduce alarm flooding.
Through the refinery staff’s efforts, they reduced the number of alarms by 40%. Reports also help uncover instrumentation problems earlier resulting in improved reliability. Continuous improvement is made possible through key performance indicators generated in these reports including:
…alarm volume, average time to acknowledge, and peak active alarm time. A summary report is also issued on a monthly basis to senior staff throughout the refinery.
The article’s author recaps their use of the DeltaV Analyze tool as:
…not just an alarm management system, but more importantly as a tool to improve operational performance. Evaluating the results achieved from an alarm management perspective alone greatly understates the software’s value, as including process improvements shows significantly improved return on investment.
Read the article for more about how the combination of technology, people and processes improved performance at this refinery.
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