Gas chromatograph

The Sitrans CV process gas chromatograph based on micro-technology rapidly and precisely determines the calorific value of natural gas. The main use of Sitrans CV is for custody transfer of natural gas. Examples are pipeline monitoring, gas transfer and distribution stations, as well as gas liquefaction and regasification of LNG terminals. The device has a rugged and explosion-proof housing, is compact and is suitable for use in extreme conditions from -20 to +55°C. Sitrans CV can be mounted directly next to natural-gas pipelines and delivers measuring results in fewer than 3 mins.

The Sitrans CV process gas chromatograph determines all the necessary information on the quality of natural gas, such as its calorific value, Wobbe index and density in accordance with ISO 6976. The accuracy of the measurement is independent of the pressure of the sample and the ambient temperature. A display on the device shows the measuring results. The device uses miniaturised detectors and valves made with MEMS (micro-electromechanical systems) technology.

The detectors are highly linear so that only one calibration gas is needed. Due to automatic optimisation of the measuring parameters every time calibration is carried out, the device is also highly reliable.

Measurement components are methane up to nonane, nitrogen and carbon dioxide. Due to an internal sample switch function, up to four sample streams can be measured successively. The measuring accuracy is better than 0.1% and the repeatability better than 0.01%. The detection limit for pentane and higher hydrocarbons is between 10 and 50 ppm.