Lube oil compressor go to Seal oil 2

[yevzil]

Our Hydrogen Recycle compressor for Platforming (pressure suction : 17kg/cm2g, and discharge :21 kg/cm2g), which is using lube base as seal oil and lube oil as lubricant. we have been problem with system in seal oil and lube oil because seal oil reservoir level has been going up +/-70 litre/hour and equivalent with lube oil reservoir level has been going down. I supoose lube oil go to seal oil, anyone could help me to clarify these problem?

Thank you
A Yevzil

 

[zdas04]

What kind of compressor are you talking about?

David

 

[yevzil]

David, we using centrifugal compressor. Thanks.

 

[flexibox]

Bushing seals are possibly being used in conjunction with buffered oil, and the oil pressure must be maintained above the sealing pressure. The amount of oil leakage depends on shaft size and sealing pressure.. The leakage will increase as the clearance between the bushing and shaft increases, due to the radial contact. Process oil contamination and degassing the contaminated oil are major concerns, so you need to provide some more information such as cross sectional drawings and P&ID.
I am sure if you did that you will receive more responses.

Other option is to change to a Dry Gas Seal.

 

[chief]

Check your vent arrangement on your lubricating system. May be pressuring the reservoir and causing leakage into the seal area.

Offshore Engineering&Design

 

[JJPellin]

I have only seen this problem one time and the situation was very unusual. In our system, the seal oil and lube oil system were side by side. They both used the same product. The seal oil system included a large overhead tank that served as the head tank to provide the necessary differential pressure for the iso-sleeve seals. It also served as a run-down tank to provide seal oil for coast down in case both seal oil pumps were lost. Since the run-down tank was quite large, a cross over line existed to allow the operators to transfer oil from the seal oil tank to the lube oil tank to keep it from overflowing on shut down. This cross-over line had a valve that was leaking by. Since the seal oil reservoir was maintained at a level lower than the lube oil reservoir, oil was migrating from lube oil into seal oil. I recognize that this is probably an obscure example and may not be relevant to your situation. I would still check your P&ID and do a field walk-down to check for cross over lines.

Otherwise, a restricted drain line on the lube oil return could cause oil to back-up and cross over through the separation seal into the clean seal-oil return line. A plugged breather vent could cause poor drainage on the lube oil drain. A plugged breather on the seal oil drain cavity could cause this cavity to pull a slight vacuum and draw lube oil across the separation seal.

If work was done recently, I would verify that all lube oil supply orifices were correctly reinstalled. A missing orifice could cause excessive lube oil flow which might overwhelm the drain. I would verify that the lube oil supply pressure is still set correctly. A malfunctioning pressure controller could result in excessive lube oil flow.

As already noted, more information would likely result in more useful responses.


Johnny Pellin