2 replies to this topic

[rifkaaisyah]

Hi all,

 

Currently I am working on small scale LNG receiving and regasification facility FEED project. I keep wondering about recirculation line facility, which is a line that is provided to maintain LNG transfer line in cryogenic condition during holding mode (no unloading LNG from ship to onshore LNG storage tanks). I wonder if that line is necessary in small scale LNG receiving facility. Does anyone have experience in that matter? 

 

I have discussed with two clients and they have two different perspectives:

 

1. Recirculation line is needed to avoid rising temperature in LNG transfer line

 

2. Recirculation line is not needed because LNG transfer activity is usually conducted every 4-7 days for small scale LNG receiving facility. Recirculating LNG will cause boil-off gas production to increase. Recirculation line is needed for large facility where LNG unloading activity is often. For small scale LNG receiving facility, recirculation line will be cooled by the time LNG ship arrives by using boil-off gas or LNG from ship.

 

I don't have any practical experience nor detail engineering design experience regarding this matter. Could anyone share about this matter?

 

Thank you in advance.

 

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https://missrifka.com

[Bobby Strain]

You need to be careful where you get advice. You got two different answers. Now you want a tie-breaker? Surely there is someone in your organization who can provide guidance to you. That's where I would start.

 

Bobby

[Pilesar]

Whether or not to keep the transfer line cold is an economics issue. If this line is a long one, you will have a lot of surface area for unwanted heat transfer from the environment. Sometimes it is economical to build this line with vacuum insulated pipe to minimize heat transfer. Calculate the boil off for each configuration and compare the capital and operating costs. For tanker unloading to an non-recirc'd line, you will likely need to start the cooldown a day or more in advance of ship arrival to be able to handle the boiloff volume.