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Remotely measuring the hydrogen gas by using portable Raman lidar system

Choi In Young, Baik Sung Hoon, Choi Young Soo

Optica Applicata

2021

Vol. 51, nr 1

37--49

A Raman lidar system is able to detect the range of gas distribution and measure the hydrogen gas concentration remotely. This paper discusses the development of a photon counting Raman lidar system for remotely measuring the hydrogen gas concentration. To verify the developed photon counting Raman lidar system, experiments were carried out in outdoor conditions. As the results indicate, the developed photon counting Raman lidar system is possible to measure 0.66 to 100 vol% hydrogen gas concentrations at a distance of 30 m. In addition, the measuring average error measured 0.54% and the standard deviation is 2.42% at a distance of 30 m.

Hydrogen Permeation Characteristics of PET Liners Used for Type IV High Pressure Hydrogen Tanks

Nardin P., Chapelle D., Perreux D., Thiébaud F.

Machine Dynamics Research

2013

Vol. 37, No. 1

85-97

The hydrogen gas permeation through polymer materials is due to two different mechanisms : molecular and atomic diffusion. Indeed, this overall gas diffusion is strongly affected by the microstructural composition of the material, the production process, and also the experimental conditions. Consequently, the hydrogen permeation parameters, when available in the literature, are changing and unreliable. The need of an accurate knowledge of these parameters for a specific polymer, after complete process, leads us to design an experimental apparatus based on the manometric method and its corresponding numerical model. From initial approximate values roughly deduced from a first experiment, the numerical model implemented in Matlab language, allows a refining of the parameters, by fitting the simulated values to the experimental ones on successive experiments. These experiments are carried out on a sample with increasing upstream pressures from 25 bar up to 150 bar. Because of the high pressure values, the beginning of permeation experiments are affected by the gas flow disturbance due to the sharp pressure rising. Considering this delay time induced by the pressure increase, the permeation parameters are evaluated more accurately. In fact, with a single experiment the phenomenon cannot be readily separated from the so-called time-lag parameter occurring in gas diffusion through a material.

Światłowodowe czujniki z interferencyjnymi strukturami sensorowymi do pomiarów koncentracji gazów toksycznych i przemysłowych

Maciak E., Pustelny T., Opilski Z., Bednorz M., Urbańczyk M.

Pomiary, Automatyka, Komputery w Gospodarce i Ochronie Środowiska

2008

nr 1

14-16

W pracy podjęto problem optycznej detekcji gazów H2 i NH3 czujnikiem światłowodowym. Czujnik wykorzystuje warstwową strukturę sensorową, wykonaną na włóknie światłowodowym, pozwalającą wykrywać i mierzyć stężenie gazowego wodoru i amoniaku. Do detekcji H2 wykorzystano struktury Pd/TMO (TMO ang. Transition Metal Oxide) obejmujące warstwę wykonaną z tlenku metalu przejściowego (TMO) pokrytą katalityczną warstwą palladu. Warstwa TMO jest warstwą chemochromiczną, której działanie polega na zmianie jej parametrów optycznych pod wpływem absorpcji atomowego wodoru. Kataliza wodoru cząsteczkowego na atomowy następuje w warstwie palladu. Do detekcji NH3 wykorzystano struktury interferencyjne wykonane z Nafionu. Nafion wskutek oddziaływania z NH3 zmienia swoje parametry optyczne zmieniając tym samym warunki interferencji światła. Struktury sensorowe wykorzystane w czujnikach światłowodowych są warstwowymi strukturami interferencyjnymi Fabry-Perot.

The paper presents an optical-fiber hydrogen sensor and ammonia sensor. The H2 and NH3 sensor utilises a layered Fabry-Perot interferometer and includes chemical active the resonance cavity. In the present paper the authors suggest the idea of a gasochromic hydrogen sensor based on the structure of a layered Fabry-Perot interferometer located at the end of the standard multi-mode fiber. The resonance cavity is a layer of metal oxides (e.g. NiO, WO3) coated on a thin film of palladium (Pd). The sensor permits to detect and to measure the concentration of hydrogen in a gaseous medium. The idea of presented optical ammonia sensor is based on variations of reflected light spectra result from interactions of ammonia with sensing layer. The sensor head consists of Nafion layer as a resonance cavity, deposited on the face of the fibre. The optical ammonia gas sensor display a very fast response time and a fast regeneration time at room temperature.