seal oil flushing

7/31/2019 Seal Oil Flushing

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Station: NTPC-Vindhyachal BHEL Ref No. PS-DC-186-500-0006NTPC Ref No. VIN/1/TS/2/005

Sheet 1 of 20

Plant area : TURBINE

PROCEDURE FOR HYDRAULIC TEST AND OIL FLUSHING OF GENERATORSEAL OIL SYSTEM

Sl. No.

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

PLANT DETAILS

OBJECTIVE

PROPOSALS

SERVICES REQUIRED

SAFETY PRECAUTIONS

EMERGENCY PROCEDURE

STATE OF THE PLANT

METHOD

COMPLETION CRITERIA

APPENDICES

a) Drawing

b) Log Sheets


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Station: NTPC-Vindhyachal BHEL Ref No. PS-DC-186-500-0006

NTPC Ref No. VIN/1/TS/2/005Sheet 2 of 20



Sl. No.

1.0

1.1

1.2

1.3

1.4

1.5

PLANT DETAILS

Generators cooled by H2 are provided with sealoil system for preventing the leakage of H2 toatmosphere for the formation of explosive mixtureand to reduce the consumption of H2.

This system consists of tank, pumps, (Both A.C.and D.C) coolers, filters and pressure regulatorsto maintain the oil pressure at the seal body ofgenerator. Turbine oil is used for this purpose.

DC pump is meant to supply oil to the sealsduring the failure of AC power supply duringemergency conditions.

For Technical Specifications, the respective O & Mmanuals are to be referred.

The drawings enclosed at section 10.0 are

a) Schematic for oil flushing of Seal Oil Piping.Drg.No. 4:PS:TSX:0063:00

b) Control Value rack of Seal Oil System.Drg.No.4:PS:TSX:0064:00

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Signatures

NTPC BHEL


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Station:NTPCVindhyachal

BHEL Ref No. PS-DC-186-500-0006




Sl. No.

2.0 OBJECTIVE

The objective of this oil flushing is to ensure thecleanliness of seal oil piping before connecting itto the various racks of seal oil system.

STATUS

Signatures

NTPC BHEL


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Station:NTPC-Vindhyachal BHEL Ref No. PS-DC-186-500-0006



PROCEDURE FOR HYDRAULIC TEST AND OIL FLUSHING OF GENERATOR

SEAL OIL SYSTEM

Sl. No.

3.0

3.1

3.2

TESTING PROPOSAL

The oil flushing of Seal Oil System is proposedto be carried out in two stages.

Stage I Oil Flushing of Seal Oil Piping (Seal Oilrack excluded)

The oil flushing is carried out by taking the lub oilfrom lub oil supply line near bearing No.4 asshown in enclosed circuit.

The oil flushing is carried out in two parts.

PART I : includes seal oil air side supply pipeline and ring relief supply pipe lines.

PART II : includes the seal oil H2 side supplypipe line.

Stage II Oil Flushing of Seal Oil Systemincluding the various components of Seal Oilrack and the system piping.

During flushing thermal shocks on seal oil isgiven Refer Procedure for Hydraulic test andflushing of Turbine lub-oil and Jacking OilSystem. BHEL Ref.No.PS-DC-186-500-0004(NTPC.Ref.No. SIM/1/TS/2/001)

All weld joints should be hammered toremove any loose weld slag.

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NTPC BHEL


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SEAL OIL SYSTEM

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4.0

4.1

4.2

4.3

4.4

4.5

4.6

4.7

SERVICES REQUIRED

Availability of Electrical heating arrangement for heating theCW to turbine oil cooler for thermal shock operation duringoil flushing.

Availability of laboratory facility for analysis of oil sample.

Availability of service air and thinner/petrol for filtercleaning.

Availability of sufficient skilled manpower for supervision /execution of the process.

Availability of required quantity of Turbine oil

Availability of portable fire extinguisher at oil flushing area.

Availability of proper lighting and communication facility.

STATUS

Signatures

NTPC BHEL


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Station: NTPCVindhyachal BHEL Ref No. PS-DC-186-500-0006




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5.0

5.1

5.2

5.3

5.4

5.5

5.6

5.7

5.8

5.9

5.10

5.11

5.12

SAFETY PRECAUTIONS:

Readiness of stair cases, platforms, hand rails for Seal OilTank and required approaches as decided at site are madeavailable.

Safety and protection equipments like hand gloves, helmet etc

are available during the process.

Precautions taken to avoid spillage of oil and contamination ofoil.

Service water source available near the activity area.

Ensure the availability of first aid kit near the process area.

Buckets containing sand are available at process area.

Welding/cutting shall not be carried out in lub-oil flushingareas, once oil has been filled in Seal Oil Tank.

Load on Pumps shall not exceed full load current of the motor.

Provision for emergency stopping of oil pumps from local/UCBhas to be made.

Cordoning of lub-oil flushing area wherever required.

Display of caution sign boards, danger tags are provided atlocations in the test area.

Round the clock monitoring of oil flushing activity.

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NTPC BHEL


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6.0

6.1

6.2

6.3

6.4

6.5

EMERGENCY PROCEDURES:

The teams for this operation shall be aware ofthe procedure of oil flushing and act at the timeof any emergency.

They shall be aware of operation of fireextinguishers.

They shall be aware of how to act in case of anypersonal injuries.

They shall know to stop the pumps quickly incase of any leakage and then inform theconcerned higher official.

They shall be aware of re-establishing theoperation in case of system stoppage due tofailure of power supply.

STATUS

Signatures

NTPC BHEL


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Sl. No.

7.0

7.1

7.1.1

7.1.2

7.1.3

7.1.4

7.1.5

STATE OF THE PLANT

Before starting the flushing, the completion offollowing jobs should be ensured.

Erection of interconnected piping is completed.

Provide temporary connection wherever requiredas per enclosed circuit.

The temporary pipes should be acid cleaned andneutralized before installation.

Ensure that flange joints are tightened withgasket in position.

The pressure regulating valve MKW 73 AA 011and MKW 73 AA 021 have been removed and

spool pieces have been placed.

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NTPC BHEL


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Sl. No.

7.1.6

7.1.7

7.1.8

7.1.9

7.1.10

Erection of seal oil pump unit, seal oil unit, seal oilvalve rack, measuring instrument rack, seal oilstorage tank and interconnected piping iscompleted.

Physical cleaning of seal oil storage tank and sealoil tank.

Availability of power and control supply for motorsand starting panels.

Trial run of following motors and coupled withrespective pumps.

a. Air side seal oil pump motor (AC) 2 nos.

b. Emergency airside sealoil pumps motor (DC) 1 no.

c. H2 side seal oil pump motor (AC) 1 no.

Disconnect airside seal oil inlet pipes at the sealbody on both sides of generator and connect it tobearing drains by a temporary piping.

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NTPC BHEL


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Plant area: TURBINE


SEAL OIL SYSTEM

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7.1.12

7.1.13

7.1.14

7.1.15

7.1.16

7.1.17

7.1.18

Disconnect H2 side seal oil inlet and outlet pipesat seal body on both sides of generator andinterconnect it by a temporary piping.

Disconnect ring relief oil inlet pipe at seal body onboth sides of generator and interconnect by a

temporary piping into air side seal oil drain pipes.

Take out both float valves from seal oil tank. MKW03BB001.

Keep the springs of regulating valves A1, A2 andC at completely released condition.

Make necessary arrangement for heating seal oil

unto 65 70

o

C during oil flushing process.

Fire fighting system of TG Lub-oil and generator Sealoil system made available before commencement offlushing.

Acid cleaning of pipeline normally not envisaged.However, if traces of pitting observed in any of the pipeline, acid cleaning of the pipe line to be carried out(Refer Procedure No.PS-DC-186-500-0013B/NTPCRef.No.SIM/1/TS/2/001 for acid cleaning)

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NTPC BHEL


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Sl. No.

8.0 METHOD

Seal oil system is filled with oil by taking the oilsupply from seal oil storage tank. To ensure oillevel in seal oil storage tank, lub oil pump shouldbe kept running during this process or oil shouldbe filled manually in this tank. Seal oil system isfilled up in two stages as follows (ensure that allshut off and gate valves are closed).

STATUS

Signatures

NTPC BHEL


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Station: NTPC- Vindhyachal BHEL Ref No. PS-DC-186-500-0006



PROCEDURE FOR HYDRAULIC TEST AND OIL FLUSHING OF GENERATOR SEAL

OIL SYSTEM

Sl. No.

8.1

8.1.1

FILLING OF AIR SIDE SEAL OIL CIRCUIT

Open following shut off and gate valves in airside oil circuit.

MKW 01 AA 503 At seal oil storage tank

MKW 11 AA 501 before seal oil pump (1).

MKW 21 AA 501 before seal oil pump (2)

MKW 31 AA 501 before stand by sealoil pump (3)

MKW 21 AA 001 after seal oil pump (1)

MKW 21 AA 002 after seal oil pump (2)

MKW 31 AA 003 after stand by sealoil pump (1)

MKW 11 AA 504 before A1 valve

MKW 11 AA 505 after A1 valve

MKW 31 AA 504 before A2 valveMKW 31 AA 505 after A2 valve

MKW 11 AA 004 after seal oil pumps (1) & (2)

MKW 31 AA 004 after stand by seal oil pumps(3)

MKW 03 AA 502 before float valve, oil inlet

MKW 03 AA 501 after float valve, oil drains (4)

MKW 03 AA 505} for oil level gauge

MKW 03 AA 506}

MKW 71 BP 501 adjustable orifice

MKW 76 AA 513} seal ring relief oil

MKW 76 AA 523}

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NTPC BHEL


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PROCEDURE FOR HYDRAULIC TEST AND OIL FLUSHING OF GENERATOR SEALOIL SYSTEM

Sl. No.

8.1.2

8.1.3

8.1.4

8.1.5

Charge the seal oil coolers on oil side with rotarytransfer valve assembly in centre position. Whenthe coolers are filled with seal oil, turn rotarytransfer valve on one side i.e. Right hand or lefthand side to bring one cooler in service andother on standby.

Charge both seal oil filters as done in case ofcoolers and keep one seal oil filter in service bykeeping rotary transfer valve on one side.

Start and stop seal oil pump 1 for a short time tobleed air from piping until pressure gauges MKW71 CP 511 and CP 521 indicate a constantpressure.

Set three way valves MKW 71 AA 511 and AA

521 and MKW 76 AA 511 and AA 521 to positionwhere no oil passes through the volume flowindicator.

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NTPC BHEL


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Sl. No.

8.2

8.2.1

8.2.2

FILLING OF H2 SIDE SEAL OIL CIRCUIT

During filling of the air side circuit, the seal oiltank is simultaneously filled with seal oil by valveMKW03 AA 502. Oil level in this tank willcontinue to rise above the sight glass till itreaches the level of seal oil storage tank and willget drained through siphon action.

Open following shut off and gate valves of H2side seal oil circuit.

MKW13 AA 501 before H2 side seal oil pump

MKW13 AA 003 before H2 side seal oil pump

MKW13 AA 510 before C valve

MKW13 AA 503

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NTPC BHEL


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Sl. No.

8.2.3

8.2.4

8.2.5

8.2.6

8.2.7

Charge both seal oil coolers on oil side withrotary transfer valve assembly in its centerposition. When both cooler are filled with sealoil, turn rotary transfer valve on one side i.e.Right or Left hand to bring one cooler in service.

Charge both seal oil filters as done in case of

coolers and keep one filter in service.

Loosen the adjusting nut of pressure equalizingvalve MKW73 AA 021.

Start and stop H2 side seal oil pump to bleed theair from piping until the pressure gaugesMKW73 CP 511 and CP 521 indicates aconstant reading. Set three way valves MKW73AA 511 and AA 521 to position, where no oil

passes through volume flow indicator.

Hydraulic test of the seal oil piping (excludingrack) shall be carried out at a pressure of 12kg./cm2.

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NTPC BHEL


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8.4.0

8.4.1

OIL FLUSHING OF SYSTEM

Oil flushing of seal oil circuit is carried out inthree different stages.

i. Flushing of air side circuit

ii. Flushing of H2 side circuitiii. Flushing of oil impulse lines

Flushing of Air Side Seal Oil Circuit. Flushing ofair side seal oil circuit is carried out by one of theAC seal oil pumps provided in the system.During this process, oil flow is maintainedthrough seal oil cooler, filter, valve A1, A2, inletseal oil pipes: bearing drain pipes to seal oilstorage tank. Parallel to this, inlet ring relief oilpipes are also flushed in this circuit.

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NTPC BHEL


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8.4.2

8.4.3

8.4.4

8.4.5

8.4.6

8.4.7

Flushing of H2 side Seal Oil Circuit. Flushing ofthis circuit is carried out by H2 side seal oil pumpprovided in the system. During this process, oilflow is maintained through H2 side seal oil cooler,filter, valve C, Inlet H2 side seal oil pipes, H2side drain pipes, prechambers, seal oil tank.

Flushing of Oil Impulse Lines

Flushing of all oil impulse lines provided in thesystem for various pressure gauges, pressureregulators should be done by opening their rootvalves and then flushing through their isolatingvalves opened to vent. Oil should be collected inthe bucket at the root of isolating valves.

During flushing ensure that there is no oil leak inthe system. If leaks are observed stop flushing

and attend to the leaks.

Maintain oil temperature around 65-700C.

Give thermal stocks as done in Turbine lub oilsystem flushing. (Refer Procedure PS-DC_186-500-0004/NTPC Ref No. SIM/1/TS/2/001)

Changeover the filter after every one hour andclear. Cleaning of filter to be carried out byfollowing steps.

a) Clean the filter element in Kerosene /

Diesel Oil.b) Then clean the filter element with clean

marking cloth.

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NTPC BHEL


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8.4.8

8.4.9

8.5.0

8.5.1

8.5.2

8.5.3

8.5.4

8.5.5

8.5.6

c) Clean and dry the filter with compressed air.(Air pressure to be reduced sufficiently for airblowing filter)

Take sample of return oil and analyses if for thepresence of moisture & mechanical impurities.

Hydraulic test of the lines (excluding seal oilrack) shall be carried out at a pressure of 12kg/cm2 along with lub-oil system.

Restoration of Seal Oil System

On completion of oil flushing:

Drain the entire system.

Remove the temporary piping and restoreoriginal connections.

Remove the blanks provided, if any.

Connect back the impulse lines.

Reassemble the float valves MKWO3 AA 001and AA 002 in seal oil tank.

Clean both the filters and reassemble.

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NTPC BHEL


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Sl. No.

9.0 COMPLETION CRITERIA

Oil flushing for each stage may be declaredcompleted on the following basis.

No foreign particle and material present at

the filtering elements after 24 hours offlushing.

Moisture content in return oil should be lessthan 0.01% (100 ppm) and mech. Impuritiesshould be less than 0.01% (100 ppm). Forlab analysis of oil samples for mechanicalimpurities, filter of size 0.45 micron shall beused.

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Signatures

NTPC BHEL


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Sheet 20 of 20

SEAL OIL PUMP NO. 1 / 2

Oil temperature

Sl.No Date/Time Pump Dis.Pr. Bef.

Cooler

After

Cooler

Thermal

ShockRemarks

Signatures

NTPC BHEL


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seal oil flushing

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