Development of a sensor to measure gas temperature and carbon monoxide and water concentrations using a 1.58 micron tunable diode laser

A near-infrared laser operating in the wavelength region between 1577 and 1582 nm was developed to perform in-situ measurements of gas temperature and carbon monoxide and water concentration in the exhaust gas region of an electric arc furnace.{09}In order to further the development of the calibration relations necessary to relate spectroscopic data to gas temperature and concentration data, laboratory tests were completed. It was found that the gas temperature relationship was improved and can be used to predict the gas temperature within ±30 K. It was found that the carbon monoxide concentration relationship was improved by eliminating any water dependence from the relation and the equation can be used to predict carbon monoxide mole fraction within ±0.40 cm mol/tot mol. It was also found that the water concentration relationship was improved by reducing the equation to a linear relationship and the equation can be used to predict water mole fraction within ±0.88 cm mol/tot mol. Calibration issues were considered in order to define if differences in hardware between individual units may be a concern with the wide-scale use of the sensor. The sensor was tested at full-scale and it was determined that the two most important obstacles to the viability of the sensor are background infrared emissions and laser light attenuation due to dust particles in the measurement region.