|A petrochemical plant.|
Founded in 1945, the International Society of Automation is a leading global non-profit that helps more than 30,000 worldwide members as well as other professionals solve difficult technical problems, while enhancing their leadership and personal career capabilities. It also publishes the bimonthly InTech, a benefit of ISA membership available digitally, or by mail. The journal takes a practical approach to explore and discuss industry challenges, new technologies, and fundamentals.
The November/December 2011 issue featured a special section on asset management, including "Utilizing asset data for predictive asset management," written by three maintenance and engineering veterans, Alexandre Augusto da Silva, Geraldo Luiz Bellotti, and Heitor Hiroshi Chaya. Bellotti and de Silva are senior staff of Braskem SA, the top producer of thermoplastic resins in the western hemisphere. Three dozen Braskem plants in Brazil, the United States, and Germany produce over 16 million tons of resins and other petrochemicals per year. Chaya, and electrical engineer with 15 years in industrial automation, runs his own consulting firm, Chaya Automação, in San Paulo, Brazil, where Braskem maintains its corporate headquarters.
"Asset management is enabling Braskem...to move toward predictive maintenance and away from costly preventive and reactive maintenance. The key is learning what assets need special attention as their performance begins to degrade....Making repairs or replacements at the optimum time limits costs and downtime. There is also less risk of an unexpected failure shutting down...before a repair can be completed."
"One of the plants [in Brazil] has experienced a rapid return on its investment in asset management while maintaining high safety standards for people and equipment. In fact, by identifying just one previously unrecognized control valve leak, Braskem saved nearly $300,000 per year..."
The story is simple--given the complexity of Braskem's asset-management system architecture, as is capably summarized in the six-page article--but that six-figure bottom line is a guaranteed attention getter. Furthermore, the savings came not from heading off a maintenance problem at the end of the valve's service, but from detecting an entirely unrecognized problem that had been introduced at the start of its service life:
"While performing valve signature tests [intended to verify that it can function as required, from fully opened to fully closed], Braskem discovered a problem with one pressure control valve on a propylene storage tank that had to remain 100 percent closed under normal conditions. The test showed the valve to be partially open. In fact, it remained three percent open even though the control panel indicated it was closed.
"This small opening was allowing about 20 kilograms of pressurized propylene to escape every hour--a loss valued at $297,500 per year. It was later determined that the problem was caused by a calibration error at commissioning. The solution was to perform a valve-travel calibration...The air supply pressure was also increased from 32 psig to 40 psig [pound-force per square inch gauge, a unit of pressure relative to the surrounding atmosphere]. This critical valve now closes fully, and the loss has been eliminated."
Still, it's called asset management for a reason. Sometimes the optimal choice is not at all obvious, and relies on a professional placing of a calculated wager as to which of multiple possible outcomes will provide the most advantageous for the company:
"Braskem technicians...identified excessive vibration in an axial pump on a loop reactor. In fact, they were even able to identify a specific bearing as the cause an recommended shutting down the process as soon as possible. However, the ploant was producing a specific product grade and needed to continue operating for another 15 days to fulfill its commitment to a customer."
"The pump's operation was carefully scrutinized over the next 14 days using continuous on-line monitoring along with frequent visual checks at the pump....Although the bearing ceased functioning before the14-day period was up, the pump kept working."
"Staying in production over that 14-day period met customer commitment and produced sales revenue of about $29 million that might have been lost to a competitor it the process had been interrupted."
When the pump was opened up, only the bearing had to be replaced, which was completed in two days. If an emergency shutdown had been necessary due to an unexpected failure, five days would have been needed to identify the problem and make emergency repairs, custing the company more than $6 million in lost revenue."
Clearly, the old gambler's mantra about the importance of knowing when to fold and when to hold 'em has a powerful place in today's predictive maintenance toolkit.
Photo by Stopgo (Own work) [Public domain], via Wikimedia Commons.