Hello guys,
We have some lean amine(a solution of lean amine) pumps with a very short MTBF of their mechanical seals (tandem seals with api plan 52). Generally in all of our centrifugal pump a light lube oil is used as barrier fluid. As we use to have problems with the amine pumps, I've thinking about to change the barrier fluid as the lube oil does not dissolve the amine and could lead to cristallyzaztion problems.

Could you help me in order to choose a suitable barrier fluid based on your experience? (I've thinking about using just clean water)

Thank you so much in advance,
Marc

Sinectica
Barrier fluid is a term used for dual pressurized seals plan 53A,B or C. Buffer fluid is used for Plan 52 arrangements. Just terminology.
I have used Royal Purple oil on lean amine applications. I think you need to explain what type of problems you are experiencing. Do you have a cross section of the seal? Is your piping plan 11 & 52 ? What is your MTBF? Is the pump operating without vibration or cavitation?

Provide some more information on what you see with the seal, you may have wrong materials. What elastomers are you using?

Our preferred seal for lean amine is a dry gas seal. If a Plan 52 is used, we prefer 50/50 ethylene glycol and water. As you noted, this will dissolve the amine that crosses the faces.

Johnny Pellin

Hello JJPellin and flexibox, many thanks for your replies.

Sorry for the mismatch between the term barrier fluid and buffer fluid, in my case is buffer fluid as we work with an API PLAN 52.

My question is focused in general considerations about sealing amine solutions.

* I feel that light oil could not be a good buffer fluid for an API PLAN 52. As JJPellin said it would be better to work with water in order to dissolve the amine that crosses the faces. My question was in order to confirm this fact with your experience and knowledge.

* We have amine pumps working with API plan 11-52, and even with single seals and API PLAN 31/61. This last case applies to three high speed pumps (sundyne) and the MTBF with less than 10 months. I would like to know if there could be a better API PLAN for these pumps with a single seal or the only way to suceed with them is to install a tandem or double seal.

Thank you so much in advance, I appreciate so much your replies

We have a few high speed Sundyne pumps in lean Amine service. The ones I am most familiar with use single seals with an API Plan 13.
These particular pumps have very high suction pressure. I also like the self-venting property of the Plan 13 for a vertical pump in Amine. We are considering a Plan 23 for some of our Sundyne pumps in Amine.

Johnny Pellin

So is it the term Barrier fluid and Lube oil same? Why I am asking is for Plan 54 the vendor has supplied a drawing with the heading Lube oil system but it is the same tank and pump supplying Royal purple to the double seal