Characteristics and flame appearance of oxy-fuel combustion using flue gas recirculation

The pollutant emissions resulting from combustion devices are considered one of the main concerns of many researchers due to their impact on the environment and people. Emissions of nitrogen oxides (NOx) and carbon dioxide (CO2) are considered two of the most important pollutant emissions. The present study is an experimental study to investigate the effect of flue gas recirculation (FGR) on non-premixed combustion for NOx reduction and CO2 capture and storage (CCS) using oxygen mixed with recycled flue gas as an oxidizer instead of fresh air. Flame stability, flame appearance, two-dimensional flame temperature, and exhaust gas analysis were investigated with different FGR percentages. The results show that the flame is stable up to 40% recycled flue gas, but the flame temperature is reduced by about 25%, and there is a reduction of NOx from 90 ppm to 5 ppm. By using oxy-fuel combustion, the flame exhibits the same general appearance for different FGR% and has the main characteristics of air combustion without FGR.