Problem on seal gas system of the BCL-505

[smain06]

Hi every one
Happy new hear 2011
we have problem on seal gas system (DRY SEAL GAS)of the BCL-505
our seal gas system is tandem mechanical seal
We have a high delta P on the PDIT between enter seal gas and the balancing line now the delta P is 10barg but normaly is 3barg (the PDCV regulate 3 barg between both)
we had inspected the seal filters et we found one is colmated
All parameters on the system seal gas are good
The seal gas leakage primary is normaly for both tandem seal
can anyone help me to found the cause for this problem
I suspect that the problem is on the valve PDCV or on the the orifice by pass PDCV seal gas

if anyone have documentation about DRY GAS SEAL send it for me
ghzdjamel@gmail.com

regards

Smain

 

[flexibox]

If the Delta P is normally 3bar you would expect the pressure to drop as compressor Laby wears and not increase, therefore I would check the DPIT calibration, and PDCV and agree with your synopsis. Is the Gas generally Clean? I assume that you are circulating process gas to the primary seal not external gas.

 

[smain06]

Thank you for your response


In this moment the DELTA P of the compressor A is 10 barg but the primary leakage seal and pressure are low that that the delta P and pressure of the second compressor B
See scema attached
My opinion i have two point
1- Maybe the problem is located inside the sealing system there some dirty existing between stationay and rotating part for both seal don't allow the opening the 3 micro clearence for that the circulation primary vent increase a bit
2- There some dirty before Orifice on line supply seal gas why cuses high delta p

what do you thing about

C-701B/ THAT WE HAVE THE PROBLEM YOU CAN MAKE COMPARISON BETWEEN BOTH COMPRESSOR

djamel

 

[smain06]

ATTACHED
DIAGRAM SEALING GAS SYSTEM ON BCL-505 COMPRESSEUR NUOVO PIGNONE

 

[smain06]

ATTACHED SEALIG SYSTEM ON THE SECOND COMPRESSOR C-701A WITH DELTA P IS 3 BARG

 

[flexibox]

Point 1: If you had that situation you will most likely have face contact I dont agree I think the reason Primary Vent is low is due to seconday seal leakage. Can you check the secondary vent?
Point 2: If the orificae is blocked then the Filters are not doing their job, what is the Orifice size?

Is the needle valve upstream of the PDCV open? Check to see if it has been closed.

 

[smain06]

hi flixibox

Attached the trend for 4 days of the PDIT152 of seal gas filters, we have seeing some on the

Delta P disturbance.

We had inspected the cartridge filter, it seems a good

Maybe we have some freezing on the supply seal gas line before the orifices

What do you thing about my investigation

The Orifice size by pass seal gas filter is 2.62mm
The two Orifices size enter supply line seal gas are 4.13mm



Best regards

 

[flexibox]

I think that this needs a site visit from your seal supplier. I would put together the latest Gas Composition, P&ID and History, get you seal supplier in to have a look at your gas panel and site conditions.

Sorry about the delay, you may have seen the news about the Floods here in Australia.