The oxygen-methane diffusion flame taking place in a gas turbine reactor was investigated experimentally with emphasis on flame stability. The oxidizer is a mixture of O-2 and CO2 and the oxycombustion process was studied at different equivalence ratios ranging from Phi = 0.5 to 1.0 and different O-2/CO2 mixture composition (100/0, 80/20, 60/40, 50/50, 40/60, 30/70 and 25/75). The flame blowout condition was achieved through the reduction of oxygen percentage in the oxidizer mixture. Measurements were obtained for the flue gas temperature and concentration as well as flame visualization. It was found that the flame is very stable at the equivalence ratio of 0.65. At this ratio, the flame blows out at an O-2/CO2 blending ratio of 22/78 for the case of fuel flow rate of 6L/min and at a blending ratio of 21/79 for the case of fuel flow rate of 9 L/min. Attempts for operating the burner with less than 21% O-2 were unsuccessful at all ranges of the operating parameters and resulted in unstable operation and blowout. Moreover, it was observed that the stabilization behavior did not change significantly with the variation of the fuel volume flow rate. It was also found that both flame and flue gas temperatures are reduced with the increase of the equivalence ratio. (C) 2015 Elsevier Ltd. All rights reserved.