Investigating the Chronic High Temperature Reading on the Lube Oil System of Water Injection Pumps

Abstract

Abstract Background: Almost all water injection pumps in our area are experiencing high temperature reading on lube oil feeding line to the bearings of disposal water injection pumps and motors especially during the summer season where it reaches 71.11 °C ESD Trip Point. The objective was to determine the root cause of this chronic problem and resolve the issue in order to avoid equipment trips as well as increasing the equipment availability. Method: Two methods were being conducted which are observing the lube oil temperature of leaving all bearings and analyze the lube temperature of each bearing outlet individually. The other method is by comparing temperatures measurements that were collected in the locations right after the (Temperature Control Valve) TCV and 1 meter away from the TCV every hour during the day time during summer season. Result: Statistics reveals that the temperature of the oil coming to the bearing is much less than 68.33 °C since some of the oil temperatures reading of oil leaving the bearings are less than 68.33 °C. Likewise, comparing temperatures measurements that were collected right after the TCV to reading collected 1 meter away from the TCV show approximately 10 °C difference in reading whereas the collected reading 1 meter away from the TCV is lower. Conclusion: the temperature sensors (one for the Hi switch, one for the Hi-Hi ESD switch and one for the TCV) are currently installed right after the (TCV). In this location, the liquid is still hot and heat transfer process between both hot and cold liquids is at the beginning phase and not completed yet. Therefore, above temperature sensors will always read the temperature of the hot lube oil especially during summer season from (11:00 a.m. to 3:00 p.m.), Hi-Hi Temperature ESD switch will be activated to trip the pump. This investigation concludes that the temperature sensors shall be re-relocated from the current location to downstream in order to provide time for the hot and cold liquids mix together. Benefits: The equipment availability will be increased as the unnecessary trips and unplanned downtime of the equipment are being avoided. Hence, it increases equipment MTBF. It also reduces number of warning alarms in control room which makes operators to focus in other issues. And most importantly that the reducing maintenance time and cost (approximately, USD 10,000 cost and five days’ work were avoided per each equipment). Example work that has been avoided to resolve the high temperature issue includes checking instrumentation healthiness, cleaning heat exchanger internally and externally, checking the fin-fan conditions, inpecting and testing TCV functionality, and inpecting lube oil tank as well as the piping which incudes the whole system.