4 replies to this topic

[Said Salim]

Hello,
I am aiming to calculate the flow of natural gas through the attached control valve datasheet. (Estimation of NG going to a flare)
Pressure drop across the valve is known (72.11 Bar) and the valve opening is 50% with linear characteristic. All fluid upstream downstream properties of the control valve are known.
Can anyone guide me how to perform the calculations? or can guide to any site that will serve my purpose.?

Attached Files

•  Control Valve datasheet1.pdf   1.38MB   35 downloads
•  Control Valve Datasheet2.pdf   1.44MB   23 downloads

[latexman]

Have you tried the website of the control valve vendor?  Maybe there is technical documents in the equipment files that has sizing methodology?  One of my "go to" websites on control valves is Fisher Controls.  Google it and drill down to their sizing documentation.

[raju.kct]

Hi Said,

The flow of gas through a system is a function of inlet and outlet boundary conditions and other components pressure drop of the system.

I assume, the control valve is one of the component, which alone will not decide the flow rate.

May refer any Fluid mechanics text book for pipe loss calculations.

[Elfaghi]

you can deal with it, as the gas flows through an orifice plate by assuming the ratio of opening valve is the hole of orifice plate, and do your calculations (it is an estimate method)

 

GOOD LUCK

 

Ashraf

Edited by Elfaghi, 22 December 2016 - 04:10 PM.

[ecas]

Use the following equation: W(kg/h) = 23.3[Valve Preesure Drop (bar) x Gas Density (kg/m³)]^0.5C_v

The valve flow coefficient C_v comes from your valve data sheet. As the valve characteristic is linear and your C_v with 100 % opening is 2.55, at 50 % opening the C_v = 0.5x2.55 = 1.275

Find in Google the Emerson/Fisher Valve Handbook, it's free.