Pump performance

[TechnicalServices]

In a plant a condensate pump is not performing upto the desired ( also designed) performance.

The NPSH required for the pump is 1 meter where as the available is 3 meter. ( The condensate temp is 96 degree centigrate and the tank is open to atmosphare.).

The duty point mentioned on the data sheet says follwing:

Capacity : 1.5 m3/hr
Head :20.7 meter
Condensate Temp : 85 degree centrigrate.

I wanted to know that if the condensate temperature increases from 85 to 96 degree celcius the pump shall not delever duty point parameters though the NPSH available is more than required even at 96 degree celcius.

 

[TD2K]

What is the pump delivering for flow and head and how does it compare to the pump curve?
Have you checked the inlet piping for pressure drop to ensure you have at least 1 m available head?
Is there a suction strainer in the line that could be partially plugged and taking a larger than normal pressure drop?
Are you confident in your data, for example, the flow rate through the pump?
Is the available NPSH of 3m off the data sheet or is it a calculated value based on 96 deg C condensate?

 

[235zzzo]

Hello TS
AS TD2K says, you have to identify and to calculate all the pressure losses in suction/inlet system and to balance it with the pump required NSPH, expressed in the pump data-sheet. See any common Hidraulic manual, how to perform that basic calculation. Be aware of the temperature effect, which is related with the respective vapour-pressure it means, as higher is the condensate temperature, lesser the difference [required NSPH - installation NSPH]. Better always to consider a positive (+) margin for security reasons 20 ~ 50 %, shall we say.
Good comissionning!
zzzo

 

[saidsaz]

always start with the easiest part

do you have a meter at pump discharge ? how much it reads ?have u taken pressure measurements ? collect data do simple calculations and check on the curve where pump is operating and why ?

cheers!