Emerson Exchange 365

Harvest season is always the busiest time of year for Tereos Group. As one of Europe's largest producers of sugar, starch and bioethanol, the French cooperative processes more than 22,000 tons of sugar beets at its flagship Connantre plant every day of its four-month production campaign. Because the factory is only active those four months out of the year, even a few hours of downtime can have a significant impact on the season's yield.

For years, valve maintenance at the Connantre facility had been performed at the end of the production run. All critical control valves and those that had malfunctioned during the run were systematically removed for inspection and repair by Tereos' staff technicians.

"This process wasn't terribly expensive when we used in-house technicians, but it was quite time consuming. The system often suffered from leakage at restart because of the continual disassembly and reassembly of so many valves," says Alain Barre, process control maintenance manager at Tereos, who presented a case study on selective valve repair this week at the 2014 Emerson Global Users Exchange in Stuttgart, Germany.

"But then the retirement of many of our maintenance staff forced us to outsource valve repairs to an external vendor, which drove costs up sharply," said Barre. "We needed to find a way to improve the reliability and performance of our control valves that wasn't such a drain on resources and plant uptime."

Tereos partnered with Emerson Process Management to devise a solution based on the FlowScannerTM 6000 portable diagnostic system, which evaluates the performance of control valves under process conditions without the need to remove or disassemble the valves being tested. Using an array of pneumatic, voltage, and digital inputs, the system is able to isolate the individual valve components that require service, minimizing downtime and improving the efficiency of maintenance operations.

Tereos used several FlowScanner modules connected to standard PC laptops to measure the signature and step response for each of the 900 control valves throughout the Connantre plant. "This allowed our technicians to identify not only failed valves, but also valves and sensors that needed tuning to optimize performance prior to startup," Barre said.

"After testing was completed, individual and global diagnostic reports were compiled along with comments specifying the various corrective actions to be taken for each valve," Barre continued. "The results showed that 16 percent of the tested units required major repairs or replacement; 44 percent needed minor work; and 39 percent required no action of any kind. "This has drastically cut down on the number of valves tagged for removal each season."

"We now routinely test a third of our valves with FlowScanner on a rotating basis just after the end of every production run. We use only those spare parts that are necessary, we've reduced our plant restart time by several days, and we've solved our flange leakage problem."

"Overall, we calculate that we've reduced our maintenance costs by about 20 percent since implementing the FlowScanner system," Barre concluded. "It's an excellent tool that allows our technicians to get to the heart of the problem with little wasted time or effort."