Mlulti-functional Industrial Combustion Process Monitoring with Tunable Diode Lasers

摘要

Industrial combustion space monitoring using conventional extractive techniques experience frequent maintenance issues due to calibration drift and probe plugging from the presence of particulate matter, commonly found in industrial processes. These techniques also exhibit long sample delays attributed to both slow analyzer response times and the shear length of the sampling liens themselves. The drawback is particularly problematic on dynamic processes where the combustion space is undergoing rapid composition changes in fuel and oxidizer. The cumulative effect of the issues associated with extractive sampling results in greater difficulty and limitations for incorporating process control and optimization procedures on the process. To address the inherent issues with extractive sampling, Air Liquide and PSI are collaborating on the development of an insitu multi-functional near-IR tunable diode laser system. The system is specifically targeted for application in harsh combustion enviornments with flue gas temperatures > 1600 deg C and high particle densities. The multiplexing capability of the diode laser system allows near simultaneous detection of CO, O_2, and H_2O. These are essential species in characterizing the combustion state of the process, i.e., fuel-rich or fule-lean, and the flue gas temperature. Sensor development and testing are conducted on a 700 kW oxy-fuel pilot furnace to evaluate the performance under simulated industrial conditions. here we present pilot test results for dynamic stoichiometry changes, effect of particle entrainment, and air infiltration monitoring.