Hydrocarbon Dew-Point Dark Spot Principle


Hydrocarbon Dew-Point Dark Spot Principle The Dark Spot optical principle utilized by Michell's Condumax hydrocarbon dew-point analyzer is radically different from that of any other cooled mirror instrument. Sensitivity of the order of 1ppm (molar) of condensate enables the analyzer to detect the almost invisible films of condensate which are characteristic of hydrocarbon gases at dew point, due to their low surface tension. The optical surface is the key element of the sensor cell and comprises an acid etched, semi-matt surface with a central conical shaped depression. A well collimated beam of visible red light is focused onto the central region of the optical surface. In the dry condition most of the incident light beam is reflected from the optical surface to form an annulus ring of light. Optical detection is made of light dispersed.


Condumax II On-Line Condumax II On-Line
Condumax II On-Line is a fully self-contained hydrocarbon dew-point analyzer that uses the proven "Dark...

As hydrocarbon condensates form on the optical surface during a measurement cycle its optical properties are modified – the reflected light intensity of the annulus ring increases and there is a dramatic reduction in the scattered light intensity within the dark spot region. It is this secondary effect which is monitored and interpreted. Michell's hydrocarbon dew-point analyzer, Condumax, and advanced process moisture analyzer, Promet, can be combined to form a complete solution for natural gas dew-point quality measurement.