BOILER FEED PUMP ERECTION AND COMMISSIONING PART-IV ABC OF THERMAL POWER PLANT

Acid cleaning and oil flushing of LUBRICATION oil line of BFP

OBJECTIVE:-  To obtain clean lubrication oil and dirt free lubrication  oil tank at Hydraulic coupling.

The pipelines shall be disassembled from flange joints after initial layout and welding completion.

Each pipeline shall be acid cleaned by soaking method.

After neutralization and passivation of each pipeline, the pipelines shall be reassembled for oil

Flushing .

Oil flushing for working oil and lub. oil circuits shall be done separately. Necessary temporary

connections shall be done for this purpose. Necessary temporary connection can be done during

erection stage and after flushing temporary connection can be removed and can be used in other

units.

During oil flushing of lub. oil circuit bearings shall be initially kept bypassed using temporary loops.

Subsequently bearings shall also be included in the flushing circuit.

After completion of oil flushing the oil used for flushing shall be drained. Bearings shall be inspected

and cleaned.

Recommended fresh oil shall be topped up in the tank as per OEM manual.

Following inputs required for acid cleaning and subsequent oil flushing.

Availability of DM Water and Service Water.

Availability of following chemicals:

Hydrochloric Acid 30% Min ( IS : 265 : 1993 )

Rodine 213 SPL as inhibitor

Sodium Nitrite

Liquor Ammonia 25% ( IS : 799 – 1990 )

Lime Powder ( IS : 1540 : 1990 -Part II )

Availability of adequate number of wooden plugs

Availability of Service Air

Availability of required grade and quantity of lub. oil

Availability of L.T. Power Supply

Availability of Lab service for efficiency test of inhibitor and for testing of Moisture & Mechanical

impurities in oil .

Availability of adequate lighting and telephone facility in lub oil flushing area

Availability of manpower with tools and consumables like cloth etc

Availability of portable centrifuge / Electrostatic Oil Filtration unit.

Precaution to be taken for fire safety .

Requirement of cooling water if thermal shock  is necessary.

ACID CLEANING ( Soaking method ) -BHEL

The dissembled pipeline pieces are filled with DM water and flushed few times. It is ensured that

there is no leakage through the wooden plug provided at one end of the pipe.

5% Hydrochloric acid with 0.2% inhibitor ( Rodine 213 SPL ) is filled in the pipes. Efficiency test of

the inhibitor is done prior to its use as per NACE procedure.

The solution is allowed to soak in the pipes for 4 (four) hours and then drained in a safe place and

neutralized. This is then disposed of with plenty of service water.

The pipes are flushed with DM water for 5 to 10 minutes.

The pipes are again filled with 2.0% Sodium Nitrite & 5.0% liquor ammonia solution. The solution is 

allowed to soak for 30 minutes and then drained.

The pipe is rinsed with DM water till pH of discharged water is between 6.5 and 7.5.

The internal surface of the pipes is dried with dry compressed air.

The lines are filled with lub. oil and uniform oil film is achieved through out the internal surface of

the pipe. The ends of the pipes are kept properly capped till the pipes are reassembled.

XXX- All the operation is done at water treatment plant because acid handling facilities will be better

There. If that facilities are not there then temporary facility to be developed at site as acid mixture

Cannot be discharged in the drain.

continued to part -v


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