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The formation of hydrates or sulphur crystallizations can have a major impact on the plant’s operability.

In the worst case scenario, these solid structures, which, in the case of hydrates resemble ice or wet snow, can clog the riser thereby leading to process interruption and expensive maintenance work.

In order to prevent their formation, hydrate inhibitors are injected into the wellbore. Piston pumps are usually used for injection, producing pulsating, highly dynamic flow under high pressure.

The non-invasive ultrsonic FLUXUS flow meter is the ideal solution for monitoring the dosing rate of the injected chemicals. Clamp-on ultrasonic flow measurement works independently of the pressure inside the pipe and is unaffected by pulsations in pressure and flow. Even if the injection flow rates are getting very low - down to several liters per hour - FLEXIM is accurately capturing these low flow rates with the FLUXUS XLF clamp-on low flow meter. With its sophisticated low flow hardware, superior signal processing and calibration it is the ideal solution - especially at small pipes with high injection pressures.

Application example at a sour gas exploration site:

Sour gas contains a high percentage (up to 25%) of hydrogen sulphide, which is extremely toxic and corrosive. Thus, the extraction and treatment of sour gas is subject to strict safety regulations. Pipelines and all equipment have to be constructed from special resistant steel and offer cathodic corrosion protection. Most parts of such facilities are thus declared as potentially explosive areas.

The admission pressure at the wellhead varies, depending on the degree of depletion of the field, between 25 and 80 bar. In order to avoid crystalline deposits of sulphur in the flow string, which reaches several thousand meters underground, ethylamine is injected into the pipe under high pressure.

FLEXIM's ultrasonic clamp-on flow metering works independent of such pressure levels. Due to the extraordinary turndown ratio of the system even pulsations with a working frequency between 2 - 4 Hz (due to the pumps) are not the slightest problem for the flow meter.

FLEXIM's non-invsive FLUXUS flow meter is an elegant solution for such underlying measurement characteristics. As the transducers are not getting into contact with the medium itself, they are not subject to wear and tear by the aggressive H2S. The installation of the system can be carried out under normal process conditions - a process shut-down is not necessary.


  • Reliable non-invasive flow measurement - no leakage risk of toxic media (H2S)
  • No extra cost due to high process pressures
  • Highly accurate and reliable flow measurement - even at very low flow rates down to several liters per hour
  • Non-intrusive measurement, therefore no NACE requirements