On-Line Hydrocarbon Dew-Point Analyzer

Automatic, on-line measurement of hydrocarbon and water dew point in natural gas

Michell Instruments offers the Condumax II On-Line, a fully self-contained hydrocarbon dew point analyzer, using the proven “Dark Spot” hydrocarbon dew point measurement principle from the highly successful Condumax instrument. Combining a hydrocarbon dew point cell and water dew point measurement in the same compact and lightweight EExd enclosure, Condumax II On-Line requires nothing more than mains power to operate.

The Dark Spot™ Measurement Principle

Condumax II On-Line uses a patented chilled mirror optical measurement technique that is radically different to that of any other instrument. Sensitivity of better than 1 ppm molar (1mg/m3) of condensed hydrocarbons enables the analyzer to detect the almost invisible fi lms of condensate that are characteristic of hydrocarbon gases at dew point, due to their low surface tension and colorless appearance. The result is a breakthrough in accuracy and repeatability.

The optical sensor comprises an acid etched, semi-matt stainless steel “mirror” surface with a central conical-shaped depression, which is chilled during a measurement cycle. Collimated visible red light is focused onto the central region of the optical surface. In the dry condition, the incident light beam is dispersed by the matt surface providing a base signal to the optical detector.

During a measurement cycle, hydrocarbon condensate is formed on the optical surface and it becomes reflective due to the low surface tension of the condensate. An annular ring of light forms around the detector and there is a dramatic reduction in the scattered light intensity within the central Dark Spot™ region.


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