Pump NPSHa

[C26M13]

Hi all,

I want to determine the NPSHa for a pump (amine charge pump) with a flow rate of 350 m3/h.
I want to do HYSYS simulation to find the some data required for manual calculation. With HYSYS I want to calculate fitting and friction loss, vapour pressure of liquid at pump and velocity at pump entry.

Can you please assist me on how to simulate HYSYS to find the data required?

Thank you,

 

[EdStainless]

NPSHa is part of the pump spec, get it from the data sheet for the pump.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[georgeverghese]

If small amounts of hydrocarbons could also be dissolved in the lean amine, would be safer to use the minimum static pressure in the feed vessel as the vapor pressure of the lean amine.

 

[micalbrch]

NPSHA calculation is not complicated. Use Google or search here in the forum for "NPSHA calculation". You will easily find the formula. You do not get NPSHA from the pump manufacturer but only NPSHR. NPSHA is a system value. You definitely need the vapor pressure. Without you cannot do the calculation.

 

[C26M13]

Thanks all for your inputs.

I am actually doing the NPSHa calculation for the pump. Some data for my calculation I will take from HYSYS.
As per my post above, the three data required will be extracted from HYSYS. I still blur with the simulation.

 

[micalbrch]

Can HYSYS calculate the vapor pressure of the fluid?

 

[C26M13]

Yes... I use HYSYS to calculate the vapour pressure at high pressure that pump can handle.

What is the term of Static Head for NPSHA calculation for centrifugal, is it just the delta elevation or is the elevation plus the delta pressure head?

I would appreciate it, if someone could give an explanation of this term and NPSHA calculation for centrifugal pump

Thank you

 

[C26M13]

With this data:

Vap pressure = 201.3 kPa
Head loss = 1.891 kPa
Elevation = 1.55 m
Velocity = 2.173 m/s
Abs pressure at tank = 101.3 kPa
g = 9.81 m/s
rho = 965 kg/m3
Pump is located below the tank

what is the NPSHA?

 

[micalbrch]

Vapor pressure is about twice as high as the abs. pressure in the tank? Think about what that would mean.

 

[C26M13]

Thank you all for your comments.

I have recalculated and have got the answer.