Gas analysers provide double safety assurance in subsea compression

Two of Michell’s gas analysers have been selected to ensure safety as part of a subsea process intervention system (SPIS).

The analysers will be installed as part of a reclaim tank system, used to collect hydrocarbon liquid residues and monoethylene glycol (MEG) for treatment as well as disposing of waste gases to the atmosphere. To avoid the risk of explosion, the tank is blanketed with nitrogen. Michell’s analysers will be used to monitor the N₂ blanket for signs of oxygen and methane and to provide a warning to operators if these are detected.

The customer aims to have a 100% atmosphere of nitrogen in the tank, so accuracy and the ability to detect low levels of the two gases is essential. The XTP601 oxygen analyser has an accuracy of 0.02% O₂ and is sensitive enough to detect oxygen from parts per million levels.

The XTC601 binary gas analyser uses thermal conductivity to measure one gas in the background of another - in this instance, methane in a background of nitrogen. Accurate to 2% of span, the analyser’s highly stable sensor means that it will perform reliably for long periods.

Both analysers use non-depleting technologies which have no moving parts. This not only keeps routine maintenance to a minimum but also increases reliability in the tough subsea conditions. They also carry worldwide hazardous area certifications including, ATEX, IECEx, TC TR Ex and CSA.