Leveraging Technology For Maintenance Excellence

© 2014 Cairn India Limited

Leveraging Technology For Maintenance ExcellenceLeveraging Technology For Maintenance ExcellenceLeveraging Technology For Maintenance ExcellenceLeveraging Technology For Maintenance ExcellenceCase study at Mangala Processing Terminal Rajasthan Operation

Cairn India Ltd

© 2014 Cairn India Limited 2

Maintenance Strategy : a genuine Maintenance Strategy : a genuine Maintenance Strategy : a genuine Maintenance Strategy : a genuine mix of orchestration mix of orchestration mix of orchestration mix of orchestration and prioritizationand prioritizationand prioritizationand prioritization


What does these pics convey?What does these pics convey?What does these pics convey?What does these pics convey?•Time bound

repair/maintenance

• Defined role for excellent performance of

each pit staff

• Excellent skills

• Super co-ordination required.

• Timely refueling so as to win the RACE against

time.

It’s just an intro. . . at the end, we will be able to comprehend how these are linked to us. . .


Maintenance Excellence:

Technology and Planning

Maintenance Excellence

Effort in Maintenance

Activities

a

b

(Maintenance Excellence) X a = (Effort in Maintenance Activities) X b

Hence, (Maintenance Excellence) = (Effort in Maintenance Activities) X (b/a)

For achieving Maintenance Excellence, (b/a) > 1

i.e. Technology and Planning are stimulating agent which enhances Maintenance Excellence when it is close to it.

Technology and Planning promoted in PPT :

• Vibration and Temperature Monitoring – SYSTEM 1

• Process Flow/Pressure/Temperature trends – BABEL FISH

• Internal inspection – Boroscope Inspection

• Basic tool of quality control - Fish bone diagram

• Activity schedule charting technique - Gantt Chart

• Basic motion element study - Therbligs

• Oil analysis –Tribology


POWER FLUI

D PUMP

Power fluid pumps P 417A/B/C/D/E


P 417 C Turbine Driven-Power Fluid Pump :


Parameters Monitoring/Augmenting Reliability

FLOW/PR./TEMP.

TRENDS

VIBRATION/TEMP.

TRENDS


Underperformance :

155

160

165

170

175

Discharge pressure (bar)Discharge pressure (bar)Discharge pressure (bar)Discharge pressure (bar)

Discharge pressure(bar)

3800

3900

2ndJune

23rdJune

20thJuly

12thAugust

RPM

Pump performance comparison for turbine driven power fluid pumps.

Decrease in discharge pressure observed at same RPM


Comparing Trends in Babel fish :

Normal Trend

Before Inspection

Trend showing abnormality

Normal trend after corrective maintenance

Corrective repair job being carried out


Data Analysis through System 1:

Normal Trend Before InspectionIncreasing trend showing abnormality

Normal trend after Maiaintenance

PANEL OBS. : Decrease in throughput and discharge pressure


Culprit fixation through Orbit plot :

Distortion in orbit indicating restriction in shaft movement due to improper fluid dynamics( bearing oil or process flu id)

Normal plot

Turbine Plot Before Turbine Plot After

Pump Plot Before Pump Plot After


Problem Eradication Confirmation Through Waterfall plot :

Sub-harmonics observed before inspection showing abnormalities Plot showing pump in healthy condition


Fish Bone Diagram ApproachFish Bone Diagram ApproachFish Bone Diagram ApproachFish Bone Diagram Approach


Gantt Chart/Multiple Activity Chart :


Optimizing the PLAN:

Ineffective therbligs

Effective therbligs

Day-wise activity planning along with responsible department.

INEFFECTIVEEFFECTIVE


Implementing the work study (dismantling):

Spacer Removed

Bearing top housing removed

Barrel cover removedSplit Casing taken out of barrel


Implementing the work study(inspection):

RETAINING RING LOCATION

FLOW SPLITTER BEND 8TH STAGE

Balancing line detached at NDE side Balancing line expelled out at DE side


Implementing the work study(assembling):

Welding done with additional sleeve of duplex S31803 material.

Pump impeller shaft placed back into bottom casing

Casing box up job

Casing inserted back into the barrel


TAGTAGTAGTAG NO. NO. NO. NO. STG ZSTG ZSTG ZSTG Z----950/960/970/980950/960/970/980950/960/970/980950/960/970/980

NAME Steam Turbine Generator

MAKE Triveni Turbines Limited

TYPE Multi stage condensing turbine

NO. OF STAGES 9

MODEL SCG-3

LOAD 12 MW

INLET PRESSURE 4035 KPa

INLET TEMPERATURE 370 ̊ C

LUBE OIL Turbinol 46

DRIVENDRIVENDRIVENDRIVEN EQUIPMENT : ALTERNATOREQUIPMENT : ALTERNATOREQUIPMENT : ALTERNATOREQUIPMENT : ALTERNATOR

MAKE Weg

POWER RATING 12 MVA

VOLTAGE 11 KV

STEAM TURBINE GENERATORSTEAM TURBINE GENERATORSTEAM TURBINE GENERATORSTEAM TURBINE GENERATOR

STG Z-950/960/970/980/

990


Sectional arrangement of Turbine

TURBINE

GEAR

BOX

Problematic area :Thrust bearing

Active thrust padNon Active thrust pad


Thrust Bearing ArrangementThrust Bearing ArrangementThrust Bearing ArrangementThrust Bearing Arrangement


Observations:Observations:Observations:Observations:

� It was found that Z-950 Active thrust bearing temperature started increasing rapidly.

� Heavy slicing was observed on the trailing edge of active side thrust bearing.

� Variation in thrust bearing worn out pattern of STG Z-950.

Thrust collar

50% wear out of surge pads


History of thrust pad failure

STG No. of failure in thrust bearing Remarks

Z-980 01 50% erosion of pad.

Z-970 01 50% erosion of pad.

Z-960 0 NA

Z-950 05 Varying erosion of pad.

S.No. Equip.Tag Failure description Date of failure ST G put back to operation on

1 Z-980 Main Rotor Thrust Bearing since commissioning 21-10-2011

2 Z-970 Main Thrust Bearing failed 18.07.2012 19.07.2012

3 Z-950 Main Rotor Thrust Bearing 11.05.2012 12.05.2012

4 Z-950 Main Thrust bearing failed. 29.08.2012 30.08.2012




Note : The frequency of thrust pad failure increased in Z-950


Fish Bone Diagram :Fish Bone Diagram :Fish Bone Diagram :Fish Bone Diagram :

OUTCOME:

1. Lube oil flow was ensured at 5 locations so as to ensure that there is no oil starvation.

2. Lube oil pressure was appended by increasing the inlet oil hole diameter on each tilting pad.

3. Boroscopy was done and found no choking on blades due to any scaling.

4. Non uniform contact of thrust pads with thrust collar was ruled out by checking thrust collar run out and blue matching.

5. Concerns about manufacturing defect were communicated with M/s Michelle Bearing, found no abnormality.

6. Inadequate float setting.


Probable Causes of failure:� Localized heating of pads due to oil starvation/oil flow restriction.� Wrong Bearing fitment� Non-uniform contact and wear pattern due to thrust collar run-out. � Choking of blades due to scaling� Difference in DBSE and coupling length� Poor quality of oil� Bearing housing centering/alignment condition causing the lube oil flow restriction at lower operating

clearance areas.

Thrust collar run-out checked

Ensuring lube oil flow at 5 locations


Remedial Actions taken #1� Bearing oil inlet hole diameter increased from 2.2mm to 3.0mm.� The thrust pad failure problem solved in STG Z-970/980 after increasing the bearing oil

inlet hole diameter. Problem still persisted STG Z-950. � Increasing bearing oil inlet hole diameter idea didn’t work� Blue match of the tilting pads with thrust collar confirmed to ensure proper bearing fitment.� Lube oil analysis was verified with 2 different labs and properties of oil were found within

acceptable range.� Boroscope inspection did not revealed any abnormality.

Oil inlet hole diameter in each pad increased from 2.2 mm to 3 mm

Boroscopy for internal inspection


Remedial action taken #2

� Increase in oil inlet diameter didn’t solve the problem in STG-950.Hence we tried to reduce the axial thrust on active thrust pads by–

� Inserting shim of 1.5mm between High Speed coupling and coupling hub, thus increasing the coupling length.

� It was done to counter act/eliminate the undue axial force acting on active thrust pads.


Trend in ZTrend in ZTrend in ZTrend in Z----950950950950

0

20

40

60

80

100

120

ROTOR THRUSTNONACT

ROTOR THRUSTACTIVE

Max. temp on Active side : 51° C

BEFORE AFTER


Summary :Summary :Summary :Summary :

� Hence, the technological advancement for maintenance excellence :

• Should continuously innovate to suit to the demands operational requirement.

• Offer a reasonable and sound value proposition for its customer.

• Aim to be smart always from discovery to deliver by associating, questioning, observing , networking and experimenting.

• Provides increased component operational life and availability.

• Allows for preemptive corrective actions.

• Results in decrease in equipment and/or process downtime

• Lowers costs for parts and labor

• Provides better product quality

• Improves worker and environmental safety

• Raises worker morale

• Increases energy savings


THANK YOU

Reducing downtime through Maintenance & reliability excellence, the game of true Operational excellence can be materialized by learning the game, gaining the game and reinventing the game.

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Leveraging Technology For Maintenance Excellence