Gas velocity in pipe

[God1knows]

Does anyone know where I can find any information in relation to the max velocity in gas pipes/ pipe is steel, delta P=12MPa, Dia 100mm. I have a reference of kinetic energy of 20,000kg/ms^2, which looks like it should be 200,000kg/ms^2!!
The line is a by pass line around a 900mm ball valve.

 

[SNORGY]

That looks like a "rho-vee-squared" criterion, derived from API-14E. (vmax = C/(sqrt(rho)). If so, 20,000 is probably closer to being correct than 200,000. I have seen C = 122 for metric units commonly used.

API (and others) have since published other limits, contingent upon other factors such as dryness, solids entrained, etc. For clean, dry gas the "C" value might indeed be higher than 122, but I rarely see C = 447.

Regards,

SNORGY.

 

[God1knows]

I looked at API 14E which relates to the errosion in relation to velocity, but is not 100% suitable to my situation. Also found this NORSOK standard which mentions 200,000kg/ms^2. What do you think? I'm not too interested in the long term process, just the equalisation around the 900mm valve.

 

[SNORGY]

The NORSOK standard seems specific to flare lines. For those lines, Mach Number criteria appear to be used instead of API 14E.

For an intermittently used bypass around a block valve, I would be inclined not to even worry too much about a velocity limit, unless you are laden with solids.

Regards,

SNORGY.

 

[ukd]

If pressure drop is not critical, velocity will be the limiting factor and apart from erosion,vibration and noise have to be considered.

As far I know,NORSOK P-001 states V=K(1/density)^0.43, K-175, d-gas density in kg/m3 and velocity in m/s or 60 m/s whichever is lowest.

API and NORSOK is conservative..

If your application is intermittent,you can even exceed 60 m/s provided you have taken care of vibration/noise issues..

Regards
UKD