Biasanya LO function test diadakan sebelum sebelum shaft rolling dan sesudah LO flushing dinyatakan accepted (maunya NAS berapa? 6, 7 atau 8 ?). Lube Oil – tidak lazim diadakan function test secara regular / priodic since the lubricating system is always in service, sebelum started (rolling the shaft) sampai shutdown…bahkan setelah shaft tsb full stop…..lube oil tetap in service, untuk menjaga oil film tetap melapisi bearing surface, kecuali ada oil mist system (itupun hanya untuk maintenance need).

Tanya – Alda Adrina

Dear all,

As a matter of fact, the lube oil system is a critical part in turbo machinery. We must make sure that this system works well. For that reason, do we need to do function test regularly? If so, is there any standard that regulates the frequency of lube oil system function test? Thanks before.

Tanggapan 1 – teuku adamsyah

Dear Alda,

Sorry for using bahasa Indonesia since I am not expert cas cis cus in other languages.
Oke, langsung ke hal yang ada hubungan dengan LO (baik pre lube, operation maupun post lube).

1. Biasanya LO function test diadakan sebelum sebelum shaft rolling dan sesudah LO flushing dinyatakan accepted (maunya NAS berapa? 6, 7 atau 8 ?).

2. Lube Oil – tidak lazim diadakan function test secara regular / priodic since the lubricating system is always in service, sebelum started (rolling the shaft) sampai shutdown…bahkan setelah shaft tsb full stop…..lube oil tetap in service, untuk menjaga oil film tetap melapisi bearing surface, kecuali ada oil mist system (itupun hanya untuk maintenance need).

3. Dalam waktu tertentu, shaft yang panjang (biasanya steam turbine) harus diputar 90, 180 dan 270…untuk menghindari deflection dari shaft tersebut, LO tetap inservice…tapi mungkin sudah menggunakan AC driver (boleh jadi turning gear oil pump) bukannya shaft driver lagi.

4. Lube Oil (begitu pentingmya), maka ada back-up system, biasanya pump motornya ada yang AC, DC dan shaft driven (operating condition).

5. Perhatikan sebelum LO started, pastikan buffer air udah inservice, biar LO nya enggak kelayapan ke seal gas. Untuk Compressor jika belum ada buffer air buat ngeseal itu LO(biasanya 5 – 10 PsiG dari working gas), boleh pakai Nitrogen….yang penting dijaga jangan sampe LO rembes ke dalam seal gas. Tau sendirikan gimana kalau oil bercampur gas di tekan dalam pressure dan temperature tertentu…jadinya apa??

6. LO function test biasanya hanya untuk package yang baru (setelah LO flushing)..atau package tersebut udah lama nganggur..itu aja, jadi karena keterbatasan saya, sampai sekarang ini belum pernah lihat ada standarisasi buat melaksanakan LO function test secara periodik untuk turbo machineries.

Terima kasih,

Tanggapan 2 – Alda Adrina

Dear Teuku,

Thanks a lot for the explanation. I think i did not make the question clear.
In our turbo machinery, there is a periodic running test of auxiliary lube oil pump. Just to make sure that the aux pump will run when the LO pressure drops or the main pump trips. Operator periodically tests the aux pump once (1x) a week. Is there any regulation about this? What shall the test frequency be? Thank you.

Tanggapan 3 – teuku adamsyah

Dear Alda,

Well, picture is clear, than I may have the answer.

1. Yes, you are correct – aux. pump is energized to pick-up the load (overlapping) soon when his get signal / indication showing the shaft driven pump discharge press. below the minimum set point – this is an automatically test.

Normally, function test of pre-lube /post-lube (AC driven) backup lube system (DC driven) performed automatically once a week and once every 24 hours for DC driven – or refer to your O & M Manual. Also these can applied for the packages with 2 LO systems (MLO and SLO – for Jet Engine or Aeroderivative type).

2. And your operator can also manually perform a function test by manipulate PLC to force the logic to run AC pump or DC pump without interupt the operation.

What shall the test frequency be? you just refer to O & M Manual…I am sorry I am not able to answer this question.

Terima kasih, bye

Tanggapan 4 – Ismail Hanafiah@qatargas

Can you provide how many Lube oil pumps are available in your system and what are the driven?

Tanggapan 5 – Alda Adrina

Dear Ismail,

I don’t know for sure, but there are more than 10 LO console, the pump is motor driven.
Any suggestion?

Tanggapan 6 – Ismail Hanafiah@qatargas

Dear Alda,

Thanks for the clarification about the turbo machinery in your plant i.e, GE steam turbine but I still do not have enough information about your system for example the frame size and the services.

In general to ensure high reliability on the critical components of turbo machinery auxiliary system, such as lubricating systems:

The lube oil system provided with the auxiliary lube oil pump driven by an AC motor for use when the main pump fails. A secondary emergency pump driven by a DC motor provides oil to the bearing when coast down in situations where the ac power is not available or the auxiliary pump fails when machine coast down by any reason such as emergency shutdown.

I have no experience with GE steam turbine but for GE gas turbine units there is a recommendation to perform weekly checks on DC emergency lube oil pump. You can refer to Technical information letter (TIL) 1469-2R1.

You can request GE to put you on the distribution list for technical information letter.

Please let me know if you require the above TIL.

Currently GE proposed to increase reliability by converting a shaft driven pump to a modern all- motor pumping system and including the full flow filter system.

Does your system support this recommendation?

Just additional information, the current trend to drive the schedule inspection for GE machines have been shifted from time base to condition base.

Thanks and Regards,

Tanggapan 7 – roeddy setiawan

Dear Alda,

I am surprised that you had to do a test on aux pump that frequent

but your turbine manual should have that recommendation in place, just browse thru the manual you will found it there.

just curious what was the maker of the turbine in question .

I dont remeber if any general recomm has been in public domain, but i may obsolete. but i dont want to touch my turbine until next scheduled inspection which bit varies from place to place.
but 8000 hr was generaly accepted for inspection purpose.

Tanggapan 8 – Alda Adrina

Dear Roeddy,

I’ll take your recommendation, thank you. It might be explained well there in the manual.
It’s a GE steam turbine anyway, Roeddy. Thanks again.

Tanggapan 9 – Budhi, Swastioko (Singgar Mulia)

Kebetulan nih… Milis Migas Indonesia sedang membuat rencana untuk mengadakan lubes clinic. Jadi segala permasalahan mengenai minyak pelumas akan dibahas tuntas pada workshop lubes clinics. Persiapannya akan dilakukan pada 29 Juni 2008 bertepatan dengan Ulang Tahun Ke-7 Milis Migas Indonesia yang jatuh pada hari ini 25 Agustus 2008 (tapi syukurannya tanggal 29 Agustus 2008). Jadi Alda jangan melewatkan kesempatan kopi darat tanggal 29 Agustus 2008 yah.

Tanggapan 10 – Sulistiyono

Typo ya 29 Juni 2008 ?