what is the maximum gas velocity in gas pipeline? 1

[HamzaHBA]

Hello,
I want to know how to determine the maximum velocity in gas pipeline. Currently, I'm working under a project of gas distribution network of low pressure (< 4 bar)...

thanks

 

[katmar]

With a low pressure, clean gas you will be more constrained by pressure drop than by velocity considerations.

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"An undefined problem has an infinite number of solutions"

 

[SNORGY]

Most companies that I know default to the API RP 14E correlation in the absence of other directions.

In Metric units, Vmax = [K/(rho)^0.5]

where K = 122, rho = density (kg/m^3), Vmax = velocity (m/s)

If you are carrying lots of sand or droplets consider K = 60.


Regards,

SNORGY.

 

[zdas04]

SNORGY,
That number is for liquids.

HamazaHBA,
Maximum velocity in gas pipelines is an economic discussion, not a physical one. Higher velocities imply higher friction pressure-drops, so that requires more hp to recover lost pressure. Each project must do the balancing act between bigger pipe and more compression.

A lot of people use 100 ft/sec (or some totally arbitrary number in that range) as the design max for natural gas lines.

Pressures under 4 bar create problems that are new to Oil & Gas operations. Virtually every rule of thumb that people use for these decisions are pretty valid above 10 bar(a), between 4 bar(a) and 10 bar(a) they get progressively less precise, and below 4 bar(a) they are mostly useless.

Also, at your pressures make sure that you are using the isothermal gas flow equation (which you have to iterate on friction factor) instead of one of the closed form equations--none of the closed form equations are very close below 4 bar(a). Using AGA Fully Turbulent or Panhandle A to get to velocities at these pressures will lead you astray.

David

 

[BigInch]

Gas transmission pipelines will normally hold below 60 fps and that might be too high as well. While 100 fps might be OK for short lengths through a connection when you have clean gas and spare pressure, too much pressure is lost at higher velocities to make any economic sense over long distances.

We are more connected to everyone in the world than we've ever been before, except to the person sitting next to us. Lisa Gansky

 

[zdas04]

I talked to a gas transmission company last month that uses 60 fps as their minimum velocity. I asked "why?" and they said that that is what was in their standard. I asked what the maximum velocity was and they didn't have one.

David

 

[ione]

You can alco glance at Norsok P-001

http://www.standard.no/PageFiles/1134/P-001e5.pdf

 

[BigInch]

Oh they have one, they just don't know they have it.

We are more connected to everyone in the world than we've ever been before, except to the person sitting next to us. Lisa Gansky

 

[C2it]

Last time I worked on the British national gas transmission system, the max velocity quoted was 20m/s.