Hot oil seal plan selection

[DieguitoI]

Good morning,
I got an offer for a centrifugal pump for hot oil service. Operating temperature 300°C. Vendor propose seal plan API 01 with single mechanical seal. In my experience this service requires double seal with buffer fluid circulating through an air or water cooler for remove heat from seals. I suspect Vendor has no experience in this service and is just trying to get the order. Anyone can share its experience in seal pan selection for hot oil pumping service?

 

[JJPellin]

The absolute temperature is not as important as knowing the vapor pressure margin. Is this temperature very close to the boiling point of the liquid at operating pressure in the seal chamber? We have pumps that operate hotter than this with Plan 11, 13, 54, 32 and others. As long as the seal is a high temperature bellows design and it has an adequate vapor pressure margin, it might be possible to operate with a Plan 01. If the product is at or close to auto-ignition temperature, then it would be wise to drop the temperature of the fluid in the seal chamber or install a dual seal. I would not normally consider a Plan 21 for service this hot. I would not normally consider Plan 52 or 53 with a cooler for these sorts of high temperatures. One of our most critical charge pumps operates at this temperature with a Plan 02 and has had excellent reliability in heavy gas oil service.

Johnny Pellin

 

[Rputvin]

I usually ask the vendor why they made a selection if it doesn't fit my expectations. It usually results in one of 3 things;

1. There was miscommunication or misunderstanding and the right equipment is selected/quoted
2. I realize the vendor is not correct for my needs
3. I learn something from the expert I'm asking to make a selection

 

[DieguitoI]

@Johnny Pellin
Thanks for your reply. Liquid is far away from boiling point, however is above flash point. Would you explain why no considers plan 52 or 53 for this service?

 

[JJPellin]

Oil this hot would not be in our LDAR (leak detection and repair) program and so it would not be monitored for VOC emissions. There would not be an environmental driver for a dual seal. Selecting a barrier fluid for temperatures this high could be tricky. We have good reliability in hot oil with single seals with steam quench. Why spend the higher cost for dual seals if they are not needed?

Johnny Pellin

 

[pierreick]

Hi,
You should talk to big name like Burgmann or flowserve to support your work.
Take a look at the doc attached.
note : did you consider Sealless pump ? my experience is with Hermetic pump for hot oil due to safety issue .
Pierre