NO reduction in 0.03-0.2 MW oxy-fuel combustor using flue gas recirculation technology

Abstract

In the present study, the NO emission characteristics have been experimentally investigated for the oxy-fuel combustors using flue gas recirculation (FGR) technology. In order to find the optimal inlet arrangement and operating conditions of the FGR oxy-fuel combustor, the flame stability tests have been carried out for various oxy-fuel combustor. The oxy-fuel combustor with two separate oxidizer nozzles yields the most stable flames in a wide range Of CO2 ratios. The NO emission characteristics are also experimentally analyzed for the various operating conditions of 0.03 and 0.2 MW FGR oxy-fuel combustors. Based on experimental results, the detailed discussions have been made for the effects Of CO2 ratio, FGR ratio, and oxygen flow-rate ratio on the NO emission. When the 0.03 MW oxy-fuel combustor is operated at the 40% FGR ratio, the NO emission level is below 30 ppm and the reduction ratio of NO emission is approximately 93%. In the 0.2 MW FGR oxy-fuel combustors operated at the 40% FGR ratio, the NO emission level is below 150 ppm and the reduction ratio of NO emission is approximately 85%. Experimental results clearly indicate that the present FGR technology is quite effective for reducing the NO emission in the oxy-fuel combustor.