In-situ measurement of pyrolysis and combustion gases from biomass burning using swept wavelength external cavity quantum cascade lasers

Abstract

Broadband high-speed absorption spectroscopy using swept-wavelength external cavity quantum cascade lasers (ECQCLs) is applied to measure multiple pyrolysis and combustion gases in biomass burning experiments. Two broadly-tunable swept-ECQCL systems were used, with the first tuned over a range of 2089-2262 cm⁻¹(4.42–4.79 µm) to measure spectra of CO₂, H₂O, and CO. The second was tuned over a range of 920-1150 cm⁻¹(8.70–10.9 µm) to measure spectra of ammonia (NH₃), ethene (C₂H₄), and methanol (MeOH). Absorption spectra were measured continuously at a 100 Hz rate throughout the burn process, including inhomogeneous flame regions, and analyzed to determine time-resolved gas concentrations and temperature. The results provide in-situ, dynamic information regarding gas-phase species as they are generated, close to the biomass fuel source.

Citation

Phillips, M. C.; Myers, T. L.; Johnson, T. J.; Weise, D. R. 2020. In-situ measurement of pyrolysis and combustion gases from biomass burning using swept wavelength external cavity quantum cascade lasers. Optics Express. 28(6): 8680-8700. https://doi.org/10.1364/OE.386072.