Michell Instruments OptiPEAK TDL600 moisture analyser for natural gas

Michell Instruments has announced its latest moisture analyser for natural gas - the OptiPEAK TDL600. Using tuneable diode laser spectroscopy (TDLAS) technology, the analyser offers high accuracy with a lower detection limit of less than 1 ppmV.

Because TDLAS moisture analysers measure the reaction of molecules to specific frequencies of light, changes in the background composition of the gas usually requires that the analyser is adjusted to maintain its accuracy. Michell scientists have developed the Dynamic Methane Compensation System (D-MET) to overcome this problem. With D-MET, the analyser is able to measure moisture in natural gas with varying compositions (such as blended gas from multiple fields or following bio-methane or re-gasified LNG injection) without the need for manual software correction factors to be made. With increasing statutory requirements in many regions for bio-methane to be added to gas distribution networks, the analyser already meets these parameters.

The company has developed a laser lock system which automatically monitors the optical profile of the gas absorption peaks to ensure the laser remains locked to the correct water absorption signal, maintaining a high integrity measurement at all times. In existing TDLAS models, laser drift results in a reduction of sensitivity.

The product provides a fast response because the optical measurement technology is non-contact. This means there are no wet-up or dry-down times - measurements can be made immediately. None of the sensing components are subjected to the gas stream, protecting them from aggressive compounds and harmful contamination. Calibrated traceable to NPL and NIST, the analyser also has worldwide hazardous area certification, including ATEX, IECEx, cMETus, TC TR Ex.

With an integrated sampling system and small footprint, the analyser can easily be retrofitted in to existing plant infrastructure. Due to the inherent stability of the instrument, regular field calibration is not required under normal operating conditions. The analyser will perform for many years with basic maintenance and housekeeping.