Determining High Liquid Level (HLL) for LPG Tank

hii ......

while determining level or measuring it you can either have a meauring device for hp head (pr gauage ) .. and you can calibrate accordingly .. multiplying volume by 90% will not do beacause higher the dia for same volume more stealy will be the rise in level with volume

• It needs to be set lower than any overflow connection, so as to give a warning that, unattended to, an overflow may happen
• It needs to be set lower than any level that is likely to be encountered at the top of the temperature range for this particular liquid, so as to allow for its thermal expansion. Do allow for the thermal expansion of the tank materials as well.

That's it.

If it causes process problems, in that high level is hit before the process volume has been added to the tank, then the tank is too small.

Thanks friends..

But i just want to design the HLL for my horizontal-ellipsoidal head vessel.

According to Wikipedia-LPG, LPG storage are filled only within range of 80-85%.

So how to determine the max liquid level inside the tank? Is there any reference about it?

Thank you..

Why is it required to know the liquid level.

If you have a 1000Lt tank fill it with 850 Lt there you will have 15% for liquid expansion which is required, as for the level it will vary with temperature, also unless you have factored in the temperature when you fill the tank you will not know the exact number of litres with which to fill your tank in the first place to arrive at 85%. As such you must calculate the expansion factor and fill more or less than 850Lt.

So the liquid level is irrelevant as you should be working with volumes or weight of LPG.

I am not good at attaching graphics,so I will try to convey in words.

If the tank is horizontal and has a 2:1 Elleptical head ,then when the liquid in the vessell is h,(from the bottom of the tank)then the volume of liquid at that position is

V=3.14159*h*h(1.5D-h)/12

where D is the diameter

These formula can be found in any pressure vessell handbook.

There are other formulae for different kind of head.

Well thanks srini..

Anyways, In what book can i find that formula? I had checked my Eugene's Pressure Vessel Handbook, but i still can not find it, except (almost) similar formula in page 418 "Partial volumes in horizontal cylinder", but i think that formula still can not solve my question.

Thank you very much for the info.

Cheers..

the maximum fill on an LPG tank is a function of outside temperature. At 100 degrees F, they should not be filled over 90%. At 110 F, 85% Below 100 F, 95% is maximum.

In case people don't know, LPG tanks will not over flow, the pressure will increase and the PSV will open and dump the LPG until the TEMPERATURE drops and the pressure drops.

I've seen LPG tanks overfilled at 60% full because some "non condensables" got into the system.. The relief valve goes off to vent those gases.

I do not think the poster of this question appreciates the temperature requirement as it relates to the level of LPG in the tank as someone has given me a negative for off topic. Perhaps that person would care to prove me wrong if they can?