Hydraulic System Curve

[RefineryRR]

Hi, All

I've done numerous system curves but the impact of control valves always gives me hassles.

When developing a system curve, how do you incorporate the consideration/impact of a control valve? To me, the head loss across a control valve is a function of both % plug extension/travel and flow rate. But does anyone have an equation/formula for determining the control valve head loss.

What I would like to do is develop my system curve to have the control valve at 40% extension, and the operating point at BEP at that control valve extension.

Any thoughts?

 

[EmmanuelTop]

See if the attached article helps.


Dejan IVANOVIC
Process Engineer, MSChE

 

[bimr]

Start upstream of the valve at a point where the pressure is known (for example a pump where the pressure can be determined from the head curve) and subtract the pressure loss in each of the fixed segments until you arrive at the control valve. That will give you the maximum pressure at the control valve.

Working backwards from the endpoint of the system, add the pressure loss in each of the fixed segments until you arrive at the control valve. That will give you the minimum pressure at the control valve.

The control valve should operate between these maximum and minimum pressure points.

See the attachment.