Emerson Exchange 365

Oman India Fertiliser Company S.A.O.G (OMIFCO) is a joint-venture business established to operate a state-of-the-art two-train ammonia urea fertilizer manufacturing facility in the Sultanate of Oman. Plant capacity is 1,750 tons per day of anhydrous ammonia and 2,530 tpd of granular urea. All production is shipped to India to support that country’s growing agriculture industry.

Ali Al Siyabi, Inspection Manager for Oman Indian Fertilizer Company, explained that the utility area of the plant produces steam for use in processing ammonia and urea fertilizer. The plant has four KP KPW heavy-duty boiler feedwater pumps. One of the two turbine-driven pumps must be in service at all times to assure full production of steam. There are also two motor driven backup pumps.

The two turbine-driven pumps, which are critically important in providing steam at the rate necessary to maintain fertilizer production, had a history of thrust bearing problems. Even though casing vibration checks were carried out fortnightly, and proximity and RTD monitoring were done continuously online, OMIFCO maintenance personnel were never able to detect emerging problems in time to prevent sudden thrust bearing failures. This happened every year or two, causing damage in the journal bearing area.

“During the last failure, a turbine rotor was damaged as well,” said Ali Al Siyabi. “The boiler had to be taken out of service, resulting in substantial production losses. The vibration data collection system in use ignored high frequency data and did not recognise the warning signs of imminent bearing failure.”

In October 2012, OMIFCO began using Emerson’s CSI 2130 Machinery Health Analyzer to gather vibration data from these machines every two weeks. This portable analyser quickly and accurately identified developing faults in rotating machinery and helped get to the root cause of the problem. Data collected by the CSI 2130 can be uploaded to AMS Suite where detailed analysis takes place. This includes advanced detection of bearing and gear faults using Emerson’s patented PeakVue technology.

With this vibration technology, OMIFCO technicians quickly identified a potential problem in a turbine thrust bearing. The impacting faults were readily visible in PeakVue waveform long before any significant increase in overall vibration was noticed. As a result, OMIFCO engineers began to carefully monitor that machine. In February 2013, a sudden 50 per cent increase in PeakVue spectrum and waveform was observed, followed a few days later by another large increase. At this time, a slight increase in turbine horizontal vibration velocity was evident for the first time.

At this point, the machine was taken out of service to check the thrust bearing, which was found to be severely damaged with large pitting in the inner race and additional small pitting in the balls. After the thrust bearing was replaced and the machine put back into service, all of the vibration readings returned to normal levels.

Emerson’s Asad Malik then explained that PeakVue is a unique analysis technique for detecting early impacting in bearings and gears in high frequency ranges. “PeakVue is used in addition to the normal route vibration measurements that will detect lower frequency faults,” he said. “PeakVue separates very high frequency, short duration stress waves from regular vibration data. Stress waves accompany metal-to-metal impacting, fatigue and scuffing/wear. By analysing the data the true amplitude and frequency of the impacting can be captured.”

OMIFCO prevented unexpected breakdowns through early identification of defective turbine thrust bearing through the use of PeakVue technology, and initiated route cause analysis to avoid failures in the future. Using the old vibration system this condition would not have been detected. As a result of using PeakVue Technology, OMIFCO saved critical machine and production downtime.