An Infrared Laser Fault Detection Method for Hazardous Waste Incineration

We have conducted an evaluation of optical methods for the detection of upset conditions in the incineration of hazardous waste. Online detection of upsets is extremely important to avoid sending untreated waste out the stack piume and to avoid the formation of hazardous PICs (e.g., dioxins). The analysis was conducted by running numerical simulations of hazardous waste combustion using detailed elementary chemical kinetic mechanisms. The results of the simulations were examined to select the components that had strong correlations with poor combustion. It was found that small hydrocarbons are the strongest candidates for in situ monitoring of combustion efficiency. The optical method that comes closest to meeting the requirements for an ideal process monitor is infrared absorption using tunable diode lasers (TDLs). This paper demonstrates the tunable diode laser detection of methane and carbon monoxide in laminar premixed and diffusion laboratory flames and discusses the transfer of this technology from the laboratory to the field.