INVESTIGATION OF OZONE STIMULATED COMBUSTION IN THE SGT-800 BURNER AT ATMOSPHERIC CONDITIONS

The effect of ozone (O-3) in a turbulent, swirl-stabilized natural gas/air flame was experimentally investigated at atmospheric pressure conditions using planar laser-induced fluorescence imaging of formaldehyde (CH2O PLIF) and dynamic pressure monitoring. The experiment was performed using a dry low emission (DLE) gas turbine burner used in both SGT-700 and SGT-800 industrial gas turbines from Siemens. The burner was mounted in an atmospheric combustion test rig at Siemens with optical access in the flame region. CH2O PLIF imaging was carried out for four different seeding gas compositions and seeding injection channel configurations. Two seeding injection channels were located around the burner tip while the other two were located along the center axis of the burner at different distances upstream the burner outlet. Four different seeding gas compositions were used: nitrogen (N-2), oxygen (O-2) and two ozone/oxygen (O-3/O-2) mixtures with different O-3 concentration. The results show that the O-3 clearly affects the combustion chemistry. The natural gas/air mixture is preheated before combustion which is shown to kick-start the cold combustion chemistry where O-3 is highly involved. The CH2O PLIF signal increases with O-3 seeded into the flame which indicates that the pre-combustion activity increases and that the cold chemistry starts to develop fur ther upstream. The small increase of the pressure drop over the burner shows that the flame moves upstream when O-3 is seeded into the flame, which confirms the increase in pre-combustion activity.