8 replies to this topic

[August]

For unloading LNG from the truck, a liquid return line is required. It says the liquid return is to balance the unloading flow. Normally I only add the vapor return line from tank to truck. How does the liquid return line work? How to specify the return flow?

Thanks

[IGC]

All of your posts seem quite similar... have you just started working at AGA or someone? haha.

 

You would probably have a recycle line on your pump for you to return liquid when priming the pump, but I've never seen a liquid return line before.

[Bobby Strain]

I never heard of such. Where did you find such requirement?

 

Bobby

[farid.k]

Agreed with bobby

[breizh]

August ,

A sketch to clear our doubts !

 

Breizh

[August]

All of your posts seem quite similar... have you just started working at AGA or someone? haha.

 

You would probably have a recycle line on your pump for you to return liquid when priming the pump, but I've never seen a liquid return line before.

 

I am recently assigned to a project which is excuting by a very small engineering office.

There are full of very strange stuff in there work and nobody could explain to me why, like the liquid return line, like using TRV release gas, using Aspen to calculate pressure drop in the line and give heat loss to a fully insulated line, size RV's without failure case study, and the back pressure of all the RV's is atm. Then size vent flare system separately.....

 

I am not very often involved in the detail engineering. There can be something that I don't know.

All my discussions with the process engineer ends up with silence or quote" we have been Always doing in this way, take the example from the old projects, it was done by the previous engineer and it is approved by the authority"

 

I am so frustrated recently. Luckily, I can still get some advices here.

[Art Montemayor]

Hilary:

 

Your use of English is very convoluted and difficult to understand.  Our members are obviously finding it hard to interpret what you mean by such terms as "return liquid line".  If you are unloading LNG (liquefied natural gas) you would normally employ a Return VAPOR Line - not a liquid return line.  As Breizh has recommended, an engineering sketch would greatly facilitate everyone in understanding the application and the problem.

 

Your personal data lists you as in Belgium.  Perhaps you can use French - or even Flemish to describe your problem.  In any event, a drawing and/or graph are universal language tools and assist greatly in conveying an accurate message between engineers.

 

Our members can certainly you in a lot of the areas you list, but you must assist them in describing your query accurately and in detail.  We are all here to help when we can.

[IGC]

 

 

Ah, good luck.  As Art mentioned - you are in Belgium?  Antwerpen?

 

Personally, I don't know why you would have a liquid return line.  Could it possibly be an overflow line to protect the vessel?  Is there an alarm on the line, maybe related to a flow transmitter?  

Edited by IGC, 19 July 2017 - 02:47 AM.

[August]

Thanks for all the replies.  I've found the answer.

 

They simply copied the PID from the previous project.  In that project, a pump was installed in the filling station.