differential pressure level measurement lpg spherical tank 2

[garciaf]

Here is my issued.

There are 3 spherical tanks of lpg, with two system level. The first one is guided wave radar level measurement, the other one is differential pressure level measurement.
Both the guided wave radar and differential pressure level measurement were not working properly at the first time we received lpg, we had a indication level in DCS (control room), but this measurement was not correct.
also in pipe tubings for differential pressure had leaks, so the measurement was going to get an error.
These leaks were corrected, but we fill the spherical to a cetain level and later we sold the product and the spherical tank stay a residuary.

we sold the product, and the tank had a residuary, later we corrected the leaks of union tubings of the diffrential pressure level, but a person adjust the zero to this new level. This for me is not possible because I have a level in the spherical tank, I need to calculate this level (according to the differential pressure measure), but I dont know if it is required to have a minimum level in the sperical tank.

Help me, please. How I can calculate this level; P=pgh, the product is lpg. I need to do a compensaton due to the colum of vapor in the sperical tanks, what would be my level minimum and why?.
If I am not being clear with this explanation, my appologizes.
Thank you for your time.

 

[roydm]

Never having had to measure LPG in a spherical tank I can imagine it might be a challenge, a huge change in temperature from empty to filled I would think.

Do you have the software for the radar that will allow you to view the echo, that must be fairly defined.
Can you describe the differential pressure installation.

What is the temperature of the transmitter HP flange, is it a direct mounted seal or remote with capillary?
Is the top connection dry?

I'm sure there are others on here with LPG experience, I will be interested to learn.
Is the liquid surface well defined or is there a turbulent layer.