Remote and cross-stack measurement of stack gas concentrations using a mobile FT-IR system

Abstract

The EPA remote optical sensing of emissions (ROSE) system consists of a commercial FT-IR system and associated components installed in a van. The ROSE system was recently used to make both single-ended measurements of the emission spectra of the gas plume exiting a cement plant smokestack and also cross-stack measurements of the absorption spectra of the stack gases. The stack gases were also analyzed by conventional extractive techniques. The species NO, CO, CO2, and NH3 were observed in emission and absorption at concentrations of the order of 400, 50, 120,000, and 10 ppm, respectively. The species HCl, H2CO, HF, and SO2 (typical concentrations of 20, 6, 0.5, and 40 ppm, respectively) were observed in absorption. Stack plume temperatures determined from the emission spectra agreed with in-stack temperature measurements to within ±10%; concentration measurements agreed to within about ±20%. This paper discusses the measurement and calibration procedures and shows the spectral signatures for the various species observed in the emission and absorption measurements.