Reconstruction of spatially resolved gas phase parameters from single line-of-sight TDLAS measurements of oxy-fuel biomass combustion in a semi-industrial combustion chamber

Combustion of biomass is a promising approach to reduce greenhouse gas emissions, particularly when combined with carbon capture and storage. The development of future combustors as well as the retrofitting of existing infrastructure require a profound understanding of the underlying processes. Comprehensive experimental investigations, however, are hindered by the limited accessibility of industrial combustors, preventing the application of advanced diagnostics. This article demonstrates that spatially resolved information on the gas phase composition (H 2 O, CO 2 , CO, CH 4 ) and temperature can be inferred from single line-of-sight tunable diode laser absorption spectroscopy (TDLAS) measurements, circumventing the need for extensive optical access. Inferring spatially resolved information in the gas phase from path-integrated transmission spectra renders an ill-posed inverse problem, which is solved in a Bayesian approach that incorporates available prior information. To demonstrate the developed technique, it is employed to a semi-industrial 1 MW th combustion chamber. The obtained results using the developed non-invasive approach are found to compare well to those of an extractive gas sampling analyzer. The developed method enables a detailed characterization of the combustion process and offers insights into the effects of flue gas-recirculation. It enables comprehensive investigations of industrial systems with minimal optical access. In addition, it has the potential to eliminate the time-consuming traversing and calibration required by extractive systems and to be used for routine monitoring.