Field Experience of a Continous Real Time In-Situ SO3/SO2 Monitor
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In an effort to provide real timein situ concentration measurements of SO3 and SO2 in the flue gas of a coal-fired boiler, a continuous analyzer for SO3 and SO2 using a quantum cascade laser (QCL) spectrometer was demonstrated.

This data is very useful for controlling dry sorbent injection (DSI), monitoring acid dew point, and potential for ammonia bisulfate (ABS) formation. In situ measurements are potentially more accurate than extractive measurements in that they are not subject to biasing reactions that can occur during the transport of a flue gas sample in an extractive measurement monitor. The QCL monitor was designed by IMACC for maximum energy throughput and unattended operation in an industrial setting. After testing and generation of quantitative SO3/SO2 spectral references in the lab, the monitor was deployed to the field. The monitor has been trialed on multiple coal-fired units ranging from 480 MW to 900 MW burning a variety of coals. The SO3 concentrations reported by the QCL monitor have been verified by comparison sampling using wet test methods. The monitor has been primarily deployed upstream of the air heater in high temperature and high dust locations. The utilities also operated a variety of DSI systems at the time of the measurements. These trials have been performed both in the U.S. and overseas with both attended and unattended operation. Testing experience and operational data such as spectral resolutions, quantitative results and detection limits will be shared in this paper.

Publication Summary

  • Geosyntec Authors: Gregory Coleman
  • All Authors: Dr. Curtis Laush, Gregory Coleman
  • Title: Field Experience of a Continous Real Time In-Situ SO3/SO2 Monitor
  • Event or Publication: Air Quality 9
  • Practice Areas: Air Quality Permitting, Compliance and Optimization
  • Date: 2013
  • Location: Arlington VA