Liquid gas level measurement

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Thread Starter

Engineer92

Dear All,

We have one close tank contains R152(HFC) liquefied gas which is being used as blowing agent/foaming agent for the extruded polystyrene. We want to measure its level. Could you please suggest which type of instrument should we use?

Waiting for your comments.
 
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>Can you give us a few details?
>Pressure, temperature, specific gravity

Pressure varies from 5 Bar to 18 Bar. When level is 15%, pressure will be almost 5 bar...when level is 90%, pressure will be almost 18 bar. Temperature is normal. Specific gravity is unknown. Before we are using bypass level gauges but display is not correct.

Waiting for your comments
 
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One would think a simple DP level transmitter should work, do you have top and bottom connections available?
How do you currently verify the level?
Others that come to mind
Guided Wave Radar with a bit of messing around
Paramagnetic, very accurate.

I would need to know more about the properties

Roy
 
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From the MDSS

APPEARANCE: Clear, colorless liquid and vapor
PHYSICAL STATE: Gas at ambient temperatures
ODOR: Faint ethereal odor
SOLUBILITY IN WATER (weight %): 0.28 WT% @ 25C (77F) (87 psia)
BOILING POINT: -25°C (-13°F)
VAPOR PRESSURE: 87 psia @ 25 deg. C (77°F)
VAPOR DENSITY (air = 1.0): 2.4
% VOLATILES: 100 WT%
DENSITY: 0.90 g/cc at 25 deg. C (77 deg. F) - Liquid

That looks pretty easy
Roy
 
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we were also thinking of using DP type level transmitter, top & bottom connections are also available. But we noticed that when tank level is 15%, pressure is around 5 bar & when level is 50%, that time pressure is 7 or 8 bar only. But when level is 80%, pressure immediately increases to around 15~18 Bar. In this case, whether DP will be a good/accurate choice? And can we use guided radar level instrument also?
 
> But we noticed that when tank level is 15%, pressure is around 5 bar & when level is 50%, that time pressure is 7 or 8 bar only. But when level is 80%, pressure immediately increases to around 15~18 Bar. <

Check out how a DP pressure transmitter works (DP = high side minus low side)
(there should be 3 columns below, but the spacing get stripped off, so imagine 3 columns separated by colons)<pre>
level : pressure : high side (level plus pressure)
minus low side (pressure)
15% : 5 bar : (15% + 5 bar) minus 5 bar = 15%
50% : 8 bar : (50% + 8 bar) minus 8 bar = 50%
80% : 18 bar : (80% + 18 bar) minus 18 bar = 80%</pre>
 
The instrument to use in a application like this is a DP with capillaries and chemical seals with the diaphragms made from the correct material for your product. Any change in process process pressure will have no influence on your measurement.

Your unknown sg of your product can also be measure by making use of a normal DP Transmitter and a piece of tubing. Just make sure you calibrate the DP Transmitter for normal clean water first.
 
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