Oil Problem on Screw Compressor

[satrio91]

Hello all..
I have some troubles with screw compressor at my plant.
FYI, spesification of the compressor :
Gea screw compressor
Type : ZR-Z48S-28
I have problem with oil system. When I turn the compressor on, the oil level always going down until 0 level and it never come back to the oil tank.
And when the operator have checked the economizer, they could drained at about 200 lt of oil which means that the oil come together with NH3 to the system. Then, I checked the coalescer and it is clean (I also attach photo).
I want to ask how can this happen?
What should I do to finish this problem?
Thank You..

 

[bcs5274]

have you checked to see if your coalescor has a hole in it allowing the oil to carry over, also check to see if the return line is open that takes oil from the filter housing back to the compressor inlet

 

[NWH]

Oil carry over past the coalesced could be caused by damage to the coalescing elements or mounting, high process gas temperatures, or due to design issues with the separator vessel. We inspect coalescing elements on regular basis, with unit TA, to verify condition.

Has this compressor train successfully run in the past? Did some event occur that corresponds to the change in oil carry over?

 

[satrio91]

NWH (Mechanical)19 Apr 17 13:09 Oil carry over past the coalesced could be caused by damage to the coalescing elements or mounting, high process gas temperatures, or due to design issues with the separator vessel. We inspect coalescing elements on regular basis, with unit TA, to verify condition. Has this compressor train successfully run in the past? Did some event occur that corresponds to the change in oil carry over?]

If I take a look by the physical appearance, there are nothing wrong with the coalescing elements. It never successfully run in the past, this problem still occur since the project has finished last year. Should I pull out the coalescing elements and inspect it to verify condition?

 

[NWH]

I would review the application with the vendor, to ensure proper selection and design, and plan to inspect at next opportunity.

We identified cause for recent oil carry over on flooded screw machine train was resolved after finding coalescing element damage and separation allowing oil to bypass the element.

 

[georgeverghese]

Check the lube oil recirculation circuit :

a) Is there a recycle PRV on a lube oil pump that is set too low or maybe malfunctioning ?
b) The type of lube oil used should be immiscible with NH3