Fiber optic hydrogen sensor for a continuously monitoring of the partial hydrogen pressure in the natural gas grid

The development of reliable hydrogen sensors will facilitate the introduction of hydrogen to the natural gas infrastructure. One of the most promising configurations for such a device is a thin film based fiber optic sensor. We demonstrate that with such a device not only the measurement of a specific threshold partial pressure is possible, but also allows for a quantitative determination of the partial hydrogen pressure measured real-time and in-situ in the gas stream. The changing hydrogen pressure, up to 200 mbar partial pressure, can be measured optically using a Pd-Au alloy thin film. However for the daily use of the sensor in the natural gas infrastructure it is important to determine the hydrogen sensing abilities under non-ideal conditions i.e. in gas mixtures containing high concentrations of CH4, C2H6, and C3H8. It is found that, the type of carrier gas (i.e. Ar (clean-conditions), CH4, C2H6, and C3H8) has hardly any influence on the measured hydrogen concentration and switching kinetics of the sensor. The sensor response times (hydrogenation kinetics) are comparable to those for clean H-2 flows. (C) 2014 Elsevier B.V. All rights reserved.