EMISSIONS OF CO AND NO FROM A TWO STAGE POROUS MEDIA BURNER

ABSTRACT

In this paper, we present measurements of CO and NO emissions and the fraction of the heat of reaction emitted as radiation for a two stage burner. The fuel-air mixtures of different equivalence ratios were burned in two separate porous ceramic sections. The primary radiating surface in this burner is the outer cylindrical surface of the porous media. We compared the two stage results to those obtained by burning the entire mixture in a single stage. The emissions of NO and CO from the two stage burner were lower than those from the single stage burner. In addition, the emissions of the two stage burner could be minimized by proper choice of the equivalence ratios in the two stages without significantly affecting the radiant fraction. Typical values of NO and CO emissions from the two stage burner were l7-30 ppm and 10-75 ppm (corrected to 0% O₂), respectively, for an overall equivalence ratio of 0.75-0.95. Typical radiant fractions were 35-45% for an energy input of 3.9-7.1 kW. For the two stage burner, the emissions and radiant fractions were relatively constant for a broad range of energy inputs.

Key Words:

• Radiant burner
• porous media
• emissions