Seal on wax feed pump

[wessim12]

hello

recently we have upgraded mechanical seal on a wax feed pump from API plan 02/62 to 02/53B/61 after 3 days we have faced leakage of barrier fluid on the outboard seal almost we top up frequency is almost every 3 hours. after opening we have discovered cock on the atmospherique side of the seal.

but all process data are within the limit , we have not see any rise on the barrier temeprature , we have well vented the loop during commissioning , cooling water also is fine we do not understand how it happen ? any suggestion

 

[Chpal1984]

So I believe most oils you need to reduce the temperature to below 120 degC prevent coking. Obviously you would expect your quench to solve the issue, I would look again at its installation to make sure its set up correctly

 

[wessim12]

we have checked everything , vibration, bearing temperature ,cooling water in / out barrier in / out pump flow, Steam temperature for plan 2 , the barrier oil is between 65 to 80 deg we could not find any thing that could leak to cock

 

[1gibson]

Are you hydraulically solid in the reservoir? What is your top up procedure, are you sure the bladder is inflated?

 

[wessim12]

we have pre-charged at 4.5 Barg and we filled the oil @ 12 barg it was just 3 days , Top up is every 25 Days alarm @ 6.5 Barg

 

[1gibson]

That's not a procedure, that's a vague enough description to let someone accomplish the work as described, and do it wrong without knowing.

 

[wessim12]

Actually , since the system was set up we have never top up only when leak started we top up to maintain the plant in a runing condition , nowe we decided to revert back to the old configuration for one pump and try to solve the issue on the other pump as we are facing the same Problems on both. we have collected all process data and send it to our seal manufacturer to check again the heat soak on the outboard seal at the same time the new seal does not have a pumping ring, we have micropump that are given flow to both DE and NDE , also we have an interlock on the DCS if the micro pump stop main pump will stop.

in conclusion , we do not understand the problem

 

[wessim12]

Any Suggestion ?

 

[wessim12]

Today , we discover that the Wax has reached 250 Deg C and drop to normal at 170 within 3h could it be the cause of faillure