Line Sizing

[dhproeng]

Can anybody provide me good material regarding line sizing.

[ibrahim]

If you can elaborate further what type of help you require. Any how following is the basic principles for Line Sizing;

- The basic principle to determine the line sizes shall be based on economical aspects, i.e., minimizing the sum of operational costs and investment costs.
- However, line sizes should be checked for following limitations also;
- Erosional Velocity
- Sonic Velocity
- Noise Velocity
- Minimum Velocity (for suspended solids or slurry)
- Flow Pattern (for two phase flows)
- In some instances, the process requirements will override the economical aspects; for example, in the case of pump suction lines where the NPSH is the main concern.
- In revamping or modification projects of existing plant, fluid velocity is more likely to be increased than in new installation projects.

Hope this may help your concern. Anyhow if you can share your details, I may help further.

[dhproeng]

I just want to desin line at given flow rate and for certain pressure drop. The process fluid is natural gas. I just need to calculate the dia. of line.

[ibrahim]

As per GPSA, Section 10, for estimating pressure drop in short runs of gas piping, Darcy-Weisbach formula can be used, assuming pressure drop through the line is not more than 10% of the total pressure.
ΔP = s.f.(L/D).(1/2).ρ.V²
where as;
ΔP = Frictional pressure drop (kgf/cm2)
f = Moody's friction factor (-)
L = Equivalent length (m)
s = Unit conversion factor 0.0000101972

a chart is attached for moody's friction factor.

[dhproeng]

Thanks Friend,
But pls tell me V is for velocity or volume.
What are the units of V and ρ.

[ibrahim]

V is the velocity in the pipeline in m/s, whereas ρ is density in Kg/m3.

for further information you can check GPSA section 17.