| A near-infrared laser operating in the wavelength region between 1556 and 1561 nm was developed to perform in-situ measurements of CO (1559.56 nm), H2O (1559.5 nm and 1559.7 nm) and gas temperature in the exhaust gas region' above a laboratory burner. In order to relate spectroscopic data to gas temperature and concentration data, laboratory tests were completed. The applicable range of conditions tested is representative of those found in a commercial electric arc furnace and include temperatures from 1250K to 1650K, CO concentration from 0∼10%, and H2O concentration from 8∼30%. Two-tone frequency modulation was used to increase the detection sensitivity. The method has been optimized and the measurement error has also been determined. Based on the results of the error analysis of the regression equations, the minimum accuracy of the technique has been estimated as 30 K for temperature, 0.76% for CO, 2.6% for H2O for all 277-test data points. This accuracy is sufficient for electric arc furnace control. Full-scale trials are underway to further assess the impacts of excessive Mie scattering from particles on the attenuation of laser power by dust present in the off-gas. |
