Before LNG/LPG can be used as an energy source or used in production for the chemical
or petrochemical industry
, it must be put through a whole series of process steps. These are to remove unwanted elements, such as sulfur and mercury, along with refining it to ensure the quality and calorific requirements are met; prior to compression, transport and subsequent use. Through all these process steps, reliable level measurements are critical for the safe and smooth operation of the plant.
There are physical properties of LNG/LPG which can also vary depending on the composition of the medium; this can be due to supplier, its origin, refined state, as well as variations on storage and ambient conditions. Due to this, many measuring principles struggle to deliver a reliable, precise measurement without recalibration. Mechanical measuring methods are known to be prone to malfunction and require a lot of maintenance. For these reasons, a contactless radar technology is clearly the measuring method of choice. However, LNG/LPG also has a low density and a very small dielectric constant (which affects its reflectivity to microwave-based radar measurement systems). In the past, this has meant special installations like stilling tubes and specific configurations of radar were required to function reliably. They also need to be able to deal with internal fittings, isolation valves, poor reflections and sometimes turbulent surfaces, and these have even presented some reliability problems for radar in the past.