How to increase NPSH of a pump?
How to increase NPSH of a pump?
(OP)
I want to increase the rates for a propane system that uses a bullet for storage at ambient temperature in equilibrium (the bullet pressure floats with ambient conditions). The increased rates will require more NPSHa than I have with the current system for a single pump according to the curves. Is there an inexpensive way to increase the NPSHa without making major piping or vessel modifications?
One idea was to put a fuel gas pad on the bullet to increase the vessel pressure for additional NPSHa. Would this work or is the system just going to find a new equilibrium at the higher vessel pressure?
I have heard of vessels put under a Nitrogen pad or other inert gas to gain NPSHa, but this depends on whether the system is compatible with the inert gas.
Is increasing the vessel pressure with a pad even an option? If so what type of pad could I use for a propane system?
Thanks
One idea was to put a fuel gas pad on the bullet to increase the vessel pressure for additional NPSHa. Would this work or is the system just going to find a new equilibrium at the higher vessel pressure?
I have heard of vessels put under a Nitrogen pad or other inert gas to gain NPSHa, but this depends on whether the system is compatible with the inert gas.
Is increasing the vessel pressure with a pad even an option? If so what type of pad could I use for a propane system?
Thanks





RE: How to increase NPSH of a pump?
RE: How to increase NPSH of a pump?
Your fuel gas would most vertainly "contaminate" you propane (unless of course its pure propane).
But the rate that this will happen in may not be high?
Then theres the N2 suggestion.While a little N2 will mix with the propane i dont think that will be much. Worth examening closer.
Another suggestion could be to increase the elevation of the vessel=increased hydrostatic pressure.
Best regards
Morten
RE: How to increase NPSH of a pump?
A tank pressure increase is a bad idea.......
Your propane tank (bullet)has very little margin for any increase in pressure. (Especially if the tank was made in the USA). Propane tanks are built for sale in a very competitive market. You are almost at 250 psig if the tank is out in the sun on a hot afternoon
Find the manufacturer's plate on the tank and see if the design pressure is 250 psig.
Consider a new pump designed for propane service.... Its not that expensive.
Where are you located..?
-MJC
RE: How to increase NPSH of a pump?
A little contamination of methane / nitrogen would be acceptable at the pump suction assuming it doesn't impact the fluids vapor pressure to the point of cavitation.
I need another 5-7 feet of head / elevation to make this work - I will look into increasing the elevation of the bullets.
I was just wondering if anyone had experience with a fuel gas or nitrogen pad for a propane system to increase NPSHa. Looking for any problems that I should avoid with this option.
RE: How to increase NPSH of a pump?
Few pump systems I have ever seen were designed to aid in reducing npsh.
rmw
RE: How to increase NPSH of a pump?
RE: How to increase NPSH of a pump?