Process Analysers Moisture Sensing Technology forProcess Gases and Liquids Applications Natural Gas Applications

Michell’s Advanced Ceramic Sensor technology provides ruggedand reliable measurement of the water dew point and moisture content in both gases and liquids throughout natural gas and petrochemical industries. Our sensors are resilient to chemical attack and will not fail even when subjected to the most severe pressure shock. The Ceramic Sensor works by adsorbing water vapour in equilibrium with the fluid being measured into its porous active layer, sandwiched between two conductive plates. High sensitivity even at ultra low trace moisture levels is achieved by use of semiconductor techniques to achieve an extremely thin active layer, protected by a micro-porous metallic surface coating. Therefore the sensor responds rapidly to changes in applied moisture, both when being dried (on process start-up) and when called into action if there is moisture ingress into a process. All Michell Ceramic Moisture sensors provide up to 1 o C accuracy and excellent long-term stability in processapplications. The unique Michell Calibration Exchange Service enables all our customers worldwide to maintain traceable certified calibration of our process moisture analysers at modest cost with minimal spares stock and down time.

Hydrocarbon Dew Point for Natural Gas

Michell's hydrocarbon dew point technology utilises the patented Dark Spot optical principle, a technique radically different from that of any other cooled mirror system. Sensitivity of the order of 5 mgm -3 of condensate enables theanalyser to detect the almost invisible industrial films of condensate which are characteristic of hydrocarbon gases at dew point, due to their low surface tension and colourless appearance. The optical surface is the key element of the sensor cell andcomprises an acid etched, semi-matt surface with a central conical shaped depression. A collimated beam of visible red light is focussed onto the central region of the optical surface to form an annulus ring of light. Optical detection is made of light dispersed. As the sensor is cooled during measurement cycle, hydrocarbon condensates form on the optical surface and 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. This highly sensitive secondary effect is used to determine the hydrocarbon dew point. •Gas quality measurements to ensure compliance to transmission pipeline tariff specifications•Avoiding hydrate formation and corrosion by monitoring glycol dehydration plant•Gas heater “Superheat” control of fuel gas to turbine power plant•Protect turbo expanders and pipeline industrial compressors from liquid impact damage

Petrochemical Applications

•Monitoring recycle gases during catalytic processes to maximise catalyst life and productivity•HDPE and LDPE process gases and liquids – ethylene, hexane, butane,… •LNG/LPG production and product checking •Liquid benzene in styrene manufacture •Diesel and aero - fuels to avoid liquid water phase separation