Equipment No.: K-21201BService:: Blower FDF for F-21201Equipment type: Centrifugal FanRotating Equipment Failure Analysis Report

Maint. Order/ Notification No.:96480741Problems detected via:

X

Routine findings.Request/Notification.Area.:2

PROBLEM DESCRIPTION

-Lube oil leak at blower DE bearing on 19/2/2014

BACKGROUND

The Equipment

Equipment Tag No: K-21201BEquipment Criticality: 1Service: Blower FDF for F-21201Equipment Type: Centrifugal FanRunning Philosophy: 1 running 1 standby (N+1)Fan Manufacturer : ZurnDriver : Steam Turbine (160kW)Rated Speed : 1500 RPMRated Flow : 140883 kg/hLast Maintenance: 10th Feb 2014 Last PM: 27th January 2014 (Coupling )Maintenance Cost : RM 37,261ULPO : No

Sequence of Event

DATA /FINDINGS:

1. Maintenance / PM history

2. Verification at sitea. CBM refer to DiagRep K-21201B_1902

3. Pi Trendinga. Trending & observation (5/2/2014 -19/2/2014)

b. Correlation of Pi observation with Fan performance curve

A-B is the region the fan was operated during the period of 7/2/2014 to 10/2/2014 . C is the average point where the Fan was normally operated . It was observed that the during the period of 7/2/2014 to 10/2/2014 the fan was forced to operated in stall region of the performance curve.

4. Vibration analysis

As overall, the fan axial displacement (pk-pk) , DE bearing temperature and Gs amplitude increased based on the data collected on the 7/2/2014 . The axial & Gs amplitude value was observed decrease after online tightening of the plunger screw (on 10/2/2014). However, the temperature shown increasing pattern. Impacting pattern of the DEs sleeve bearing was visible & these pattern still observed even after the online plunger screw tightening. The increased of the temperature taken at the DEs bearing & the visible high impacting sign on the time waveform indicating possible damage on the DEs sleeve bearing.

5. CRG Inspection (Refer to CRGs QCP dated xxx)

a. Inspected component Item : DE Pedestal BearingManufacturer : DodgeLubrication : Oil bath with oil slingerBearing Type : Sleeve bearing

b. Damaged component

The scuffing mark at the sleeve bearing indicated metal to metal rubbing which in this case the rubbing of the shaft & the sleeve bearings babbit.Its probably due to the losses of thin oil film that was separating the shaft & the sleeve bearings babbits. The insufficient of the oil level probably due to the leaking of the lubricating oil from the rubber grommet to the atmosphere.This was supported by the fact that the bearing temperature at the DE increased & reached >600C just before the blower was stopped for rectification. It was also observed that the scuffing area was badly at the side toward the gearbox compared to the side toward NDE bearing. This indicating that possibly the fan shaft was misalign/unbalancely rotating as per illustrated below at some stage of duty ;

FAILURE ANALYSIS

1.Failure analysis based on the reported problem

2.Further failure analysis on dislodged oil seal (grommet)

POSSIBLE CAUSES

Based on the collected & available evidence it can be concluded that the possible failure was due to the following ;1. Increased in system resistance due to throttling at 21FC082.pv & 21FC087.pv (refer to pi trending on 7/2/2014 to 10/2/2014 ) forcing the centrifugal fan to run in the stall region eventually making the centrifugal fan running with unpredictable flow characteristic i.e unstable.These instability possibly causing the increase in axial & DEs bearing vibration (Evidence based on vibration data taken on 7/2/2014) which eventually causing the bearing stopper to vibrate & dislodge the oil seal(grommet). Hence, oil leaked. 2. The scuffing of the DEs bearing babbits was aftermath effect. Losing protective oil film thickness due to the loss of oil lubrication (due to oil leakage) amplified by the vibration transmitted from the unbalance fan .

Failure componentFailure ModeFailure Cause

Oil Seal (grommet)Oil leak1. Bearing stopper vibrate & dislodge the oil seal(grommet)due to amplified vibration transmitted from the fan side (Fan running at stall region)

DEs sleeve bearingBearing High temperature1. Losing protective oil film thickness due to the loss of oil lubrication (due to oil leakage) amplified by the vibration transmitted from the fan

Failure Cause CategoryOperationalMaintenanceManufacturing DefectUnintended service conditionEnd of design life

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RECOMMENDATIONS:

No.Recommended Action for improvementAction byRemarks

1To operate the fan to the right side of the curve avoiding the stall region i.e >80000Nm3/h.OperatorAlternatively, if operation wish to run the fan at < 70000Nm3/h they shall require to reduce the dampener opening to ~ 40%.

2To ensure the shaft not sitting on one side during installationCRG

*Please mention in the remarks whether or not notification has been raised to appropriate parties who carry out the recommended actions.

PREPARED BYNAME : Muhammad Fadzlee SamsubahaDATE : 11/3/2014 APPROVED BY (TP)NAME : DATE :

ATTACHMENTATT:1 Diagnostic report : DiagRep K-21201B_1902ATT:2 CRGs QCP report : XXX