Gas Sensing System Employing Raman Scattering

The detection and characterization of molecular gases in a sample is a relatively difficult challenge. Usually, this task is relegated to expensive and time-consuming processes like mass spectrometry and gas chromatography. Furthermore, numerous industrial applications require such gas-phase analysis for pollution and process control; for example, in large, natural-gas-fired turbine electricity generators, large quantities of natural gas are mixed with air and burned. Because natural gas comes from a variety of sources, the composition of the gas changes often. If the composition of natural gas were known a-priori, turbine efficiency could be improved by adjusting the fuel/air mixture and other operating parameters. This control capability requires measurement of the components of the natural gas to better than 0.1% accuracy, with the measurement being performed at least once every second. There is currently no commercially available sensor or sensing system that can measure all of the natural-gas components in one second.