Measurement of unburned methane emissions in laboratory flames using mid-infrared hyperspectral imaging

Abstract

In this study, we present a novel method for measuring unburned methane (CH${}_4$) emissions in laboratory flames using mid-infrared hyperspectral imaging. Given the environmental significance of methane’s global warming potential, accurately quantifying emissions from combustion processes is critical. Our approach integrates an extended-area blackbody as the infrared source and a bandpass interference filter to mitigate issues of noise, low signal levels and detector saturation. This setup enabled high-resolution spectral analysis, capturing detailed concentration and temperature maps of methane around the flame. We tracked the dynamics of methane pockets escaping the flame using the hyperspectral imaging system in high-speed camera mode, providing insights into the behavior of unburned gases, such as the velocity of methane pockets. The study demonstrates the feasibility of this technique for assessing combustion efficiency by quantifying the flow of unburned methane through a control surface. Our findings suggest that mid-infrared hyperspectral imaging is a robust tool for remote sensing of methane emissions, offering significant advancements in the accurate measurement and analysis of combustion processes, and providing a benchmarking platform for measurement approaches intended for field applications.