Liquid gas levels – measured with electronic differential pressure

Process data

Medium

Liquid gas (LPG)

Container

Spherical storage tank

Measuring height

21 m

Tank pressure

300 mbar

Medium temperature

-10 ... 0° C

Ambient temperature

-20 ... +40° C

Application

The application Liquid gas, which is typically a mixture of propane and butane, is a by-product of petroleum refining. With its high energy content, it is an ideal fuel for cars (LPG) and for heating. It is usually stored in spherical tanks in refineries. Level measurement in these storage tanks is a real challenge. Liquid gas has physical properties that are not conducive to measurement, so only a few measuring methods are suitable for use. For safety reasons, two redundant measurement setups and a separate overfill protection system are always required. All measuring systems must be SIL2 qualified. Differential pressure transmitters with capillary systems are often used to measure the liquid levels. Due to the huge dimensions of the spherical tanks, extremely long capillary tubes are required. These tubes are exposed to outdoor temperatures, which influence the measured values significantly.

Recommended products

VEGABAR 82

The solution

The ideal solution for this measurement task is electronic differential pressure measurement with VEGABAR 82 and 86. In this master/slave system, the capillary tubes are replaced by an electrical connection. The existing wiring can still be used.In contrast to capillary systems, this measurement is affected neither by the medium temperature nor the ambient temperature. Even small level changes are recognized immediately. The user thus gets accurate and reliable measurements at all times. Since there are no capillaries, mechanical protection and maintenance of those components are no longer necessary.

The sensors deliver the medium temperature and the static pressure as measured values simultaneously. That means fewer tank fittings, simpler installation and the elimination of separate measuring systems.

User benefits

High operational reliability through reliable, accurate readings
Cost-effective instrumentation without capillaries and protective covers
Output of medium temperature and static pressure: fewer tank fittings, simpler installation, elimination of superfluous measuring points

Measuring range - Distance

Measuring range - Pressure

-1 ... 100 bar

Process temperature

-40 ... 150 °C

VEGABAR 86

Measuring range - Pressure

0 ... 25 bar

Process temperature

-20 ... 100 °C

Process pressure

0 ... 25 bar

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