Feasibility Study of Remote Monitoring of Gas Pollutant Emissions by Raman Spectroscopy.

摘要

The feasibility of using laser Raman scattering to remotely monitor the emission of NO and SO2from large stationary sources such as electric power plants was studied. Since no previous experimental measurement of the Raman scattering cross-sections was known to have been made for either NO or SO2,these cross-sections were measured in the laboratory using a 3371 A pulsed nitrogen laser as the Raman exciting source. Using N2as a normalizing standard,the results are best fit by a NO to N2Raman cross-section ratio of 0.5 + 0.1and a SO2to N2Raman cross-section ratio of 2.4plus or minus 0.3. In addition to the cross-section measurements, a field study was carried out with a laser Raman spectrometer utilizing a 3371 A pulsed nitrogen laser installed in a van at the site of large electric power plant. Raman spectra of N2, O2, H2O and CO2were obtained from the power plant stack plume at a slant range of 625feet without interference and detailed field procedures have been developed which permit quantitative profiles of the concentration of these molecules in the plume to be routinely obtained. However,NO and SO2were not observed in the field study,due primarily to the insufficient stray light rejection ratio of the monchrometer used in the present system. (Author)