7 replies to this topic

[patrick3579]

Hello,

 

What is a maximum velocity for LNG in a pipe?

 

Thank You in advance,

Patrick

[Art Montemayor]

Use a conservative, slow velocity to avoid friction losses and vaporization.  You are dealing with a saturated liquid that has no sub-cooling.  An average velocity of approximately 4-6 ft/sec should be OK.  Stay away from 10 or more ft/sec.

[patrick3579]

Thank You for fast answer!

[Bobby Strain]

I usually agree with Art. But LNG piping is expensive. So I believe if you look at LNG facility details you will find liquid velocities on the conservative side at 20 ft/sec and loading lines as high as 30 ft/sec. The longest lines, of course, are rundown to tankage and ship loading.

 

Bobby

[fallah]

Patrick,

 

In addition to what are rightly mentioned about LNG velocity limitation in relevant pipeline, it should also be limited due to more static electricity generation in higher velocity...

[patrick3579]

Hello,

 

I am using a equation as in attachment.

 

For DN25 and 0,5m3/s i get a velocity about 0,028m/s, so i think it's ok. (lower than 2m/s)

 

I am doing a calculation of small regasifitaion plant with Ambient Air Vaporizer.

 

Best regards

Patrick

Attached Files

•  Przechwytywanie222.PNG   2.71KB   10 downloads

[breizh]

http://www.wartsila-...ject_guide5.pdf

 

Hi ,

Consider this resource , LNG velocity < 3m/s for SS pipe.

 

Breizh

Edited by breizh, 20 August 2016 - 05:25 AM.

[Bobby Strain]

Capacity is quite relevant when designing piping systems. For your exercise it doesn't really matter because your project won't get built. But you can see by the responses to your query that you can get many different answers even from engineers with experience spanning several decades each. And you don't know whether any of us has experience in the area. Except Breizh has a large library for reference which he kindly shares. So, you should remember this later in your career. And, quite often, the most popular answer is not the best, or necessarily correct. And your query was not very well done. Pump inlet piping requires much lower velocity than pump discharge piping.

 

Bobby