Characterization of forest fuels in a Mass Loss Calorimeter by short open-path FTIR spectroscopy

A FTIR spectroradiometer working in a short open-path configuration has been implemented coupled to a Mass Loss Calorimeter to measure in situ and simultaneously the concentrations of the main gaseous carbon-related by-products from the combustion of forest fuels. A proper methodology to retrieve accurate values of CO and CO2 concentrations has been developed. This methodology includes the determination of the true optical path of the exhaust gases by using an infrared camera imaging at 4.4 μm. Average factors have been calculated to correct the effect of the temperature in the retrieval procedure. The determination of temporal evolution of CO and CO2 concentrations has allowed the characterization of the combustion dynamics of the samples. These results open the door to further extensions of the method to the measurement and characterization of forest fuels in a field-scale fire.

Research Highlights► FTIR spectroradiometer coupled to a Mass Loss Calorimeter to characterize forest fuels. ► The system measure in situ and simultaneously CO and CO2 actual concentrations. ► Methodology developed to manage the inhomogeneous optical path including temperature effects. ► The use of an IR camera has allowed the experimental determination of the plume path. ► Emission ratio CO/CO2 has been experimentally measured for Cistus laurifolius