Remote sensing of hydrogen gas concentration distribution by Raman lidar

Abstract

Hydrogen is expected to become an energy source in the next generation. Although hydrogen gas is a combustible gas with a large explosion concentration range, leakage is presently monitored by contact type gas sensors. The technology for locating a leak and remote sensing of gas concentration distribution is required in case of hydrogen gas leaks. In this study, remote sensing technology of hydrogen gas concentration distribution using a Raman lidar was developed. The lidar system consisted of a pulsed Nd:YAG laser of wavelength 354.7 nm and a Galilean telescope of aperture 170 mm. The system could detect hydrogen gas by vibrational Raman scattering. In this method, hydrogen gas concentration could be measured based on the ratio of the Raman scattering signals from hydrogen gas and from atmospheric nitrogen, which were simultaneously measured. In this manner, the geometrical form factor of the biaxial lidar and the instrumental function were canceled. Hydrogen gas concentration of 0.6-100% could be measured at a distance 13m using this system.