pumping of Propylene

[esdee]

hello!

i have a problem with pumping of propylene from a vessel drum.the drum is under nitrogen blanket. when the level of the drum is less than 40% , the delivery of the pump reduces until it is almost zero.
i think it might be because of propylene's volatility. Is that so? any solution to that?
thanx

 

[Montemayor]

esdee:

You haven't revealed the thermal conditions of the liquid Propylene. This is important, and I have to presume it is saturated. You also haven't told us the type of pump and the NPSHa of your system and the NPSHr of your pump.

The "pumpability" of liquid Propylene has little to do with its volatility (whatever the phrase means). It has a lot to do with the type of pump (& its characteristics), the NPSHa of your system, and the NPSHr of your pump. Even if the liquid Propylene is saturated, the ability to pump it successfully should be no problem if designed and operated correctly. If you are losing prime on your pump - as your symptoms reveal - it points directly to a NPSH flaw either in design or in operation. You should calculate your NPSHa and compare this with your pump's characteristics and its NPSHr.