2 replies to this topic

[gorilliot]

Hello everybody,

Based on my previous experiences on several onshore LNG receiving terminal projects, I have noted that BOG recondensers are more and more complex. These SS drums are now provided with plenty of split ranges, ratio controls, spill over valves, make-up gas inejction, pressure and level controls, etc. leading to potential risks of bad design and finally mal-operation during start-up (this is my REX !).
KBR, Saipem, Sofregaz, Sener, Tractebel designs are very fine but isn't possible to make the job more simply?
Finally, I am just wondering why don't se use an in-line static mixer installed on the LPP send out header (followed by a surge drum if required)?
Is there any scheme like this?

Best regards,

[Zauberberg]

Is the question here about vapor quench drums, or condensers of LNG boil-off gas? The design will be obviously different because the application is different. If you can post a general sketch of the system you are referring to, it would be helpful.

Vapor quench drums are something that becomes common for LNG plants, because there is incentive to capture and either compress or reliquefy the BOG that has been sold once already as LNG cargo. There are different technologies as you say, and each case is different as it depends on the actual compression/processing capacity of the plant (no point to quench if you there is no spare compression capacity), and on the Return On Investment in case you go for a full re-liquefaction of BOG.

Design of a BOG condenser will largely depend on where the processed stream is recycled to (pressure, temperature, vapor/liquid or pure liquid). The design I have encountered most often so far is a packaged unit consisting of a closed N2 expander refrigeration loop and heat recovery pre-exchangers). They didn't look very complicated to me but again, maybe you are referring to something else and that is why a sketch is welcome.

[Ajay Patil]

Dear Ankur,

 

OK for the control valves.

What about the instrument air consumption for I/P converter?

This instrument is also to be covered under instrument air consumption calculations.

 

Please give me information on air consumption in I/P converter. It is always bleeding some air.

As per my information it is about 5 lits/min.