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Trace Moisture Measurement with Aluminum Oxide Sensor

Trace Moisture Measurement with Aluminum Oxide Sensor
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Trace Moisture Measurement with Aluminum Oxide Sensor - 1

Application Note Trace Moisture Measurement with Aluminum Oxide Sensor in X-STREAM Process Gas Analyzers With an Aluminum Oxide sensor, the X-STREAM Process Gas Analyzer family is capable of measuring trace moisture in many challenging applications. Key features include: ■■ ■■ ■■ ■■ -100 °C (-148 °F) to -10 °C (14 °F) dew point In combination with other measurements in one housing Factory calibrated / no field calibration needed Cryogenic Gases, Natural Gas (LNG), Utility Power Generators, Heat Treating The sensor measures water in the range from -100 °C (-148 °F) to -10 °C (14 °F) dew point with an accuracy of +/-2 °C. A ppm sensor is also available with corresponding water concentrations of 0–100 ... 3000 ppm. Each sensor comes with a factory calibration. Trace Moisture Measurement range Measurement accuracy Repeatability Response time (t95) Operating humidity Sensor operating temperature Temperature coefficient Operating pressure Flow rate X-STREAM Process Gas Analyzers The moisture sensor can be combined with any other X-STREAM Analyzer technology, including: non-dispersive infrared, ultraviolet, and visible photometry (NDIR/UV/VIS), paramagnetic and electrochemical oxygen (pO2 / eO2), thermal conductivity (TCD) sensor and trace oxygen (tO2). If combined with other measurements in series, the moisture sensor is always first in the series and completely tubed with stainless steel to avoid any diffusion of ambient air moisture to the sensor. A calibration exchange program (annual interval) is available. The sensor can be used in various background gases such as CO, CO2 and natural gas. Trace Moisture (tH2O) -100 to -10 °C dew point (0–100 ... 3000 ppm) ±2 °C dew point 0.5 °C dew point 5 min (dry to wet) 0 to 100 % r.h. -40 to +60 °C Temperature compensated across operating temperature range Depending on sequential measurement system, see analyzer specification (1) max. 1500 hPa abs / 7 psig Depending on sequential measurement system, see analyzer specification (1) 0.2 to 1.5 l/min *NOTE: 1psi = 68.95 hPa (1) If installed in series to another measurement system, e. g. IR channel

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Trace Moisture Measurement with Aluminum Oxide Sensor - 2

Natural Gas Production/Transmission Natural gas is found in vast underground wells and is often a petroleum byproduct. Ethylene Glycol (anti-freeze) dehydrators are used to dry the gas. In some special applications, molecular sieve may be used. The gas industry uses a particular terminology when measuring water vapor in the gas stream. It is specified in lbs/mmft3 (pounds of H2O/million cubic foot of gas) at 15.5 °C (60 °F). This is an absolute measurement such as dew point or ppm. The normal transfer specification is 7 lbs/mmft3. This is equivalent to -38.5 °C dew point, -37 °F dew point...

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Trace Moisture Measurement with Aluminum Oxide Sensor - 3

Utility Power Transmission Heat Treating Furnaces Utility transformers are periodically taken out of service for maintenance. These transformers are filled with an insulating oil, then topped off with a pressurized nitrogen blanket. Prior to refilling, the transformers must be purged with dry nitrogen for a period of time, until the moisture inside the transformer windings has been removed. The nitrogen source must be verified as dry, then the transformer exhaust must be monitored until a certain dryness has been achieved. Heat treating furnaces may be found in numerous industries. They are...

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Trace Moisture Measurement with Aluminum Oxide Sensor - 4

Hopper Desiccant Dryers Used for drying hygroscopic and non-hygroscopic plastic resins, twin tower hopper dryers operate in the following way: a fan circulates dry air through the hopper containing plastic resins at slightly above atmospheric pressures. The moisture laden air is then sent through a desiccant bed where the moisture is absorbed from the air stream by the desiccant. An external heater then takes the -40 °C (-40 °F) dry air and raises the temperature as high as 230 °C (450 °F). This air is sent back through the hopper of resin to remove additional moisture in a closed loop....

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