How to define the discharge pressure setpoint
How to define the discharge pressure setpoint
(OP)
Dears,
I have the following pump details:
Capacity, Normal: 170 m3/h; Rated: 187 m3/h.
Suction: 1.8 barA.
Discharge: 10.1 barA.
Dif: 8.3 barA.
Service: Flash drum pump, produced water.
I would like to know how i can set up the suction/discharge trip setpoint.
Which criteria do i have to consider?
Best Regards,
ML.
I have the following pump details:
Capacity, Normal: 170 m3/h; Rated: 187 m3/h.
Suction: 1.8 barA.
Discharge: 10.1 barA.
Dif: 8.3 barA.
Service: Flash drum pump, produced water.
I would like to know how i can set up the suction/discharge trip setpoint.
Which criteria do i have to consider?
Best Regards,
ML.





RE: How to define the discharge pressure setpoint
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: How to define the discharge pressure setpoint
I have the pump system curve, it might help us. Nowdays, our setpoint is 5 bar. is it correct?; if we change it to 4 bar, is still correct? is there any relationship/percentage between discharge setpoint and discharge pressure?
System works with produced water, S.g: 1.12
Thanks for your help and support;
ML.
RE: How to define the discharge pressure setpoint
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: How to define the discharge pressure setpoint
RE: How to define the discharge pressure setpoint
we are trying to protect the pump.
RE: How to define the discharge pressure setpoint
To determine the proper set-points for these substitute trip set-points, you would need to know the full range of possible suction conditions and the pump curve. If the pressure in the flash drum is constant and stable, then suction pressure at the pump would represent drum pressure plus head pressure. If the drum pressure did not change, then any change would represent a change in level. The discharge pressure of the pump could be correlated to flow by assuming a given suction pressure and using the pump curve.
Depending on the variability of your suction pressure, this could be a very poor way to protect the pump. You could substitute a low amp trip based on field testing at low flow. A low amp trip might also provide protection for loss of suction level. Depending on the characteristics of the pump, this might not provide good protection, either.
Johnny Pellin
RE: How to define the discharge pressure setpoint
If you need to protect the pump from dry running or cavitation due to low suction level,a combination of suction pressure and level monitoring will be more appropriate. You will need to take into consideration the vapour pressure of the liquid in the determining the set point and also the NPSHR curve of the pump.Baiscally you have to work out the worse suction condition that will cause the pump to cavitate.