1 reply to this topic

[pmunishankar]

Dear All,

 

I am searching for any pipe line sizing criteria (for gases) for sizing the meter run.

 

As per API 14 E the maximum velocity for single phase gas lines is to be considered as 60 ft/s. However this limit can be exceeded if there is no noise problem. Most companies put cap on the maximum design / operating velocities in gas lines to be under 60 ft/s. 

 

What about the meter run piping sizing? I have a problem at hand - the natural gas pipeline is 14" and it is reduced to 8" for meter run. After meter run it is increased to 10" and then further increased to 16".

 

If I want to suggest what is the maximum flow rate load the pipeline system can handle, should I check for the maximum flow rate at which velocity in 8" segment approaches 60 ft/s? or is there any relaxation for meter run piping??

Are there any guidelines??

Please do share with me.

 

Thanks and Regards,

Muni Shankar

[mansari]

Considering the maximum anticipated flow rates, orifice plates are sometime sized smaller than the normal pipe size, (to keep the beta ratio in a reasonable limit). Therefore a small pipe segment (satisfying the minimum run length of straight pipe upstream and downstream of the orifice) replaces the main pipe for this length.

 

This is a very small portion and does not have any significant impact on overall pressure drop. Gas being a compressible fluid, can pass through this "restriction" without any problem, since pressure in the gas pipelines are high.

 

For your sizing calculations, you should take the size of the main line, 14" in this case. 60 ft/s is a good value, however noise issue should not become a real problem as long as velocity remains < 80 ft/s