EFFECT OF FLUE GAS RECIRCULATION ON BURNER PERFORMANCE AND EMISSIONS

Flue gas recirculation (FGR) is an effective applicable way to reduce emissions. In the present study, external FGR was employed in non-premixed combustion using kerosene as liquid fuel to investigate its effect on flame stability, appearance and emissions. Flame stability can be attained through a reasonable range of recycling ratios up to 40%. Flame appearance exhibits shorter flame with increasing FGR% due to the increased turbulent mixing. Flame temperature was reduced because of dilution effect and increased specific heat of FGR. The flame luminosity decreased and bluish flame increased by increasing FGR%. As a result of the flame temperature decrease, an obvious reduction of NO emissions can be achieved. The NO can be dropped from about 90 ppm to a single digit number. Emissions of CO and UHC increased at high recycling ratios near to flame blow-off and more increase took place at leaner conditions i.e. lowest flame temperature.