MEASURING CHLORINATED HYDROCARBONS IN COMBUSTION BY USE OF FOURIER-TRANSFORM INFRARED-SPECTROSCOPY

The quantitative measurement of products of incineration of chlorinated hydrocarbons using Fourier transform infrared (FTIR) spectrometery was evaluated during a study of the fundamental processes of toxic waste incineration. Combustion products were sampled from a turbulent flow reactor into which chlorinated hydrocarbons were injected. Chlorinated species were detected mainly in the C-Cl stretching region, away from H2O and CO2 interferences. Absorbances of species having rotational lines narrower than the instrument resolution, such as CO, CO2, and HCl, were nonlinear under most conditions. The measured absorbance of these species was very sensitive to total pressure, increasing with an increase in total pressure; at very low optical densities, however, absorbance became independent of total pressure. Thus, while FTIR spectroscopy has many features that make it attractive for measuring combustion species, care must be taken to ensure the accuracy of quantitative measurements.