Leak at LPG storage inner tank
Leak at LPG storage inner tank
(OP)
Hi everybody,
In annular space of full containment LPG storage tank, the temperature is more or less equal to inner tank thats why we suppose that there is a leak.
my question is: What are the techniques to find leak on full containment inner tank full of LPG?
do we have to empty the inner tank for inspection?
Thank you for your help.
In annular space of full containment LPG storage tank, the temperature is more or less equal to inner tank thats why we suppose that there is a leak.
my question is: What are the techniques to find leak on full containment inner tank full of LPG?
do we have to empty the inner tank for inspection?
Thank you for your help.





RE: Leak at LPG storage inner tank
I always thought the annulus was kept at atmospheric pressure and any rise in pressure indicated a leak.
Can you safely vent the space to see if it pressrises back?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Leak at LPG storage inner tank
it's a new LPG tank and it's the first filling with LPG liquid.
The annular space temp of the tank is equal to inner tank temp.
The contractor proposed to perform one of the two techniques to confirm that there is or no leak on inner tank explained below:
1. to check the variation of liquid level inside inner tank during a period.
2. to empty the tank, for internal inspection.
which technique is better?
For time being I have no other infromation.
Thank's
RE: Leak at LPG storage inner tank
You need to find out where the temperature sensor is physically located (perhaps installed too close to the inner wall) and verify readings of other transmitters in the annular space.
Next, look at the drawings and see if there is any purge (usually N2) through the insulation between the two walls, and where this purge is routed (flare or vent), and get some samples for gas composition.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Leak at LPG storage inner tank
The whole point of a double skin vessel is that an leak in the inner tank is contained, but also that you are aware of it by means of pressurisation or other sensors within the annulus.
Both "techniques" you mention seem quite poor. There should be no guesswork about whether you have a leak or not.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Leak at LPG storage inner tank
I figure something like this might offer some insight.
http://www.amazon.com/Test-Instruments-CD100A-Comb...
claimed 50 ppm
http://www.aikencolon.com/e-instruments-7899-combu...
seems to claim 1 ppm
RE: Leak at LPG storage inner tank
1 seems insufficiently accurate to rule out a leak, and offers no information about the location if it does suggest that there is a leak.
RE: Leak at LPG storage inner tank
you can find herein attached two documents: one related to sensors position around the tank and second document is related to temperature readings from 20 may 2015 3:00 PM to 27 may 2015 12:54 PM.
RE: Leak at LPG storage inner tank
RE: Leak at LPG storage inner tank
Your sketch shows "LNG". Is it LNG or LPG in question? It makes a whole lot difference with regards to evaporation temperatures.
Secondly, what is the storage temperature? What is the temperature of the liquid phase inside the tank?
Moreover, is there any Nitrogen purge through the insulation between the walls?
Your Excel file shows that all 8 temperature sensors are showing the same value, and according to the sketch they are distributed inside the perimeter of the outer (concrete) tank wall, and closer to the outer wall. I don't think this indicates a leak.
Please reply with the requested information.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Leak at LPG storage inner tank