Online condition monitoring also is an important consideration. “It depends on the equipment. If you are going to buy a $13-million compressor then you will use online monitoring. If it’s a $500,000 pump, you probably won’t. You would put this on an inspection route and get it checked three or four times a year by the four-man inspection team that does routine monitoring around the plant. The point here is that the online monitoring has to be able to pay for itself,” he notes.
As Oberbeek suggests, the push is on for suppliers to produce ever more versatile, cost-effective tools for maintenance engineers.
One example is the Spi-VR hand-held data collector from AV Technology (AVT), Stockport, England, that was originally developed as a vibration analysis tool. Its ability was highlighted in December when a European petrochemical plant developed a problem with one of two pumps supplying lube and control oil to a high-speed turbine-driven compressor. The compressor is monitored every five weeks as part of the site’s vibration-based condition-monitoring regime. Using the Spi-VR, personnel noted a step change, about three times the usual amplitude, at the pump’s drive end. By entering this information together with bearing make and model details into the condition-monitoring software program, it was possible to identify the problem as being with the bearing. The pump was taken out of service and dismantled; although the bearing didn’t feel particularly rough, when it was split deep pitting was found in the inner race.
Early detection of the pump’s developing bearing problem resulted in the need to replace only the bearing itself and a quick turnaround. If it hadn’t been detected, more serious damage would have occurred, with increased repair costs and extended machine downtime.
Figure 3 -- Broader capabilities:
Now the Spi-VR has been expanded to handle additional condition-monitoring critical data such as oil analysis, acoustic emissions and thermography information (Figure 3). The company hopes to lauch the device on the U.S. market later this year.
Another company helping plants tackle LCA and LCC is Emerson Process Management, Austin, Texas, which has already clocked up two notable successes in France in the early months of 2009.
The first is at Solvay’s largest plant at Tavaux. The productivity of its maintenance department has risen by 10% to15% following the installation of Emerson’s AMS Suite predictive maintenance software to better manage field devices. Plant staff were looking for ways to capitalize on diagnostics as the total number of devices at the plant increased to near 15,000 — more that 20% of which are complex instruments.
“During the start up of the Epicerol production unit, the process to produce Epichlorohydrin from glycerine, Emerson AMS Device Manager ensured the complete automation system, including DeltaV, was configured right the first time, allowing us to save valuable time during setup. AMS Suite is our daily tool for identifying, standardizing, configuring instruments and saving reference values,” says Giacomo D'Andrea, service manager of automation/instrumentation and electricity.
Chlorine service forms a critical part of the plant and Solvay is using Emerson AMS Valvelink, a snap-on application to AMS Device Manager, to monitor control valves. These valves are fitted with Fisher Fieldvue DVC6000 digital valve controllers, which enable a partial-stroke test to be performed every month without shutting down the plant or bypassing the valve. Partial-stroke testing enables higher reliability of the valve and reduces the need for full testing. The procedure already has successfully detected an anomaly on a valve that is critical for the unit, allowing plant personnel to address the issue before plant upsets occur.