Ultraviolet-visible chemiluminescent emission features in laboratory-scale flames have been shown by several researchers to correlate well with the flame's equivalence ratio, and it has been suggested that this relation could be used to actively control flames. This study investigated the feasibility of extending this knowledge to the industrial setting. Radiative emissions from basic oxygen furnace (BOF) and thermal generating station burner flames were mainly characterized by thermally-induced greybody spectra; emissions from electronically excited species of OH*, OH*, and CO2* were generally weak and did not offer any unique information that could be used as part of a flame diagnostic system. A sub-study which assessed the impact of biomass cofiring demonstrated that emissions of SO2, NOx, and fossil-CO2 could be reduced with direct fuel replacement. The sensor system could be used as a pyrometer, and as part of a burner balancing strategy to counter increased CO emissions and decreased efficiency.

Ultraviolet-visible chemiluminescent emission features in laboratory-scale flames have been shown by several researchers to correlate well with the flame's equivalence ratio, and it has been suggested that this relation could be used to actively control flames. This study investigated the feasibility of extending this knowledge to the industrial setting. Radiative emissions from basic oxygen furnace (BOF) and thermal generating station burner flames were mainly characterized by thermally-induced greybody spectra; emissions from electronically excited species of OH*, OH*, and CO2* were generally weak and did not offer any unique information that could be used as part of a flame diagnostic system. A sub-study which assessed the impact of biomass cofiring demonstrated that emissions of SO2, NOx, and fossil-CO2 could be reduced with direct fuel replacement. The sensor system could be used as a pyrometer, and as part of a burner balancing strategy to counter increased CO emissions and decreased efficiency.

Les variations de la composition des gaz naturels nécessitent un system de réglage automatique de la richesse de flamme pour des chaudières domestiques à gaz. Dans ce travail,deux solutions potentielles sont étudiées, à savoir la chimiluminescence de flamme et le courant d’ionisation. Des indicateurs de richesse sont déduits des signaux de chimiluminescence obtenus expérimentalement. L’impact de l’échange de chaleur entre la flamme et le brûleur sur des signaux de chimiluminescence est ensuite étudié. Une analyse est également faite des principaux facteurs pouvant perturber la caractérisation du signal de chimiluminescence. Le courant d’ionisation est ensuite étudié sur une flamme conique pour comprendre l’évolution de son intensité avec la position de sonde et avec les conditions de flamme. Il est montré ensuite que ces évolutions sont corrélées avec le changement de la distance entre la flamme et le brûleur. Enfin, une boucle de contrôle est développée pour démontrer la faisabilité d’un réglage automatique de richesse en exploitant le signal de chimiluminescence. / The variations of natural gas composition call for an automatic equivalence ratio regulation system for domestic gas boilers. Two potential techniques for this purpose are investigated, i.e. the flame chemiluminescence and ionization current. Equivalence ratio indicators are inferred from the chemiluminescence signal based on the experiments. The investigation proceeds by examining effects of the flameburner heat exchange on the chemiluminescence signal. The interference of several disturbing factors for the chemiluminescence signal characterization is also analyzed. The flame ionization current is investigated on a conical flame to understand the evolution of its intensity with the probe position and flame conditions. These changes are then attributed to modifications of the distance between the flame base and the burner rim. Finally a control loop is developed to demonstrate the feasibility of equivalence ratio self-regulation with the chemiluminescence signal.