Process Fluid Leakage

[YoYo2000]

In general, what could be the potential causes for the process fluid contaminating the barrier fluid regardless of how high the barrier pressure differential. The seal chamber pressure is monitored and does not vary much, the barrier pressure is always maintained higher, but when the barrier fluid is inspected, it is always contaminated!

Anybody experience this too?

 

[flexibox]

This may happen during the topping up procedure of a plan 53A If the pump is still running, the operator drains the N2 from the pot and seal sees reverse pressure allowing process fluid to contaminate the barrier fluid. What type of system do you have and can yo send a P&ID so we can help further.

Trust this helps, as this is all I can see causing it.

 

[YoYo2000]

This is for a buddy of mine, I will try to get more details..but it is a plan 53A..could you explain this in more detail please..what is topping up? Thank you for your help

 

[flexibox]

This is a common problem. When the liquid level drops the operator isolates the N2 vents the pot whilst the pumps are in operation. In this mode the seal is in reverse pressure and without knowing what the seal arrangement is the pressure in the seal chamber is higher than the barrier fluid which is zero during the top up procedure. This is when the operator adds barrier fluid into the pot/vessel. After he tops up the pot with barrier fluid he charges it with N2 and pressurises the seal again but it's too late because its been subjected to reverse pressure allowing the process fluid to contaminate the barrier fluid.
There are seals that can handle reverse pressure however this will not solve the problem. Sounds like you need operator training on how to operate a Plan 53A system.
Trust this helps

 

[CHoff07]

Are you sure the barrier fluid is getting contaminated and not breaking down due to the high temperatures. API Plan 53's generate a lot of heat and the higher you raise the barrier fluid pressure, the hotter everything runs, especially the outboard seal which has the highest differential pressure.

Are you using a synthetic barrier fluid?
Synthetic fluids are better at the higher temperatures and you should be using a true barrier fluid (not a lubricating oil) but if you are running a clean product fluid as your barrier – it may be breaking down due to the temperatures.

Do you have cooling water hooked up to the seal pot?
If not you should. If there is no cooling water available, you could install an air cooler to the barrier fluid.
I suggest taking an oil sample and confirming the fluid is contaminated.