Spectral radiation analysis of premixed oxy-syngas and oxy-methane flames

Oxy-fuel combustion has potential to be an impeccable enhancement of current combustion techniques. For a hydrocarbon burning with oxygen the resulting exhaust stream is composed mainly of carbon dioxide and water vapor. This exhaust allows for easier carbon capture and sequestration since the water can be condensed out. Another advantage is the significant reduction of NOx since much of the nitrogen found in air-combustion systems is eliminated. These processes also provide a higher theoretical efficiency which is advantageous. Although beneficial many of the exhaust gas products radiative characteristics are unknown. Motivated by this, this paper focuses on the spectral radiation measurement of oxy-syngas and oxy-methane combustion. This is important for combustion system designers since radiating heat from the flame is the primary source of the heat flux going into the combustor walls. In this experimental study, spectral radiation of premixed oxy-syngas and oxy-methane data was collected from 1.2μm to 5μm wavelengths with varying firing inputs, equivalence ratios, and CO2 recirculation ratios. The study finds that oxy-fuel combustion flame displays 3 to 5 times stronger spectral intensity than a conventional air combustion flame. It is also found from this experimental study that spectral intensity increases 10 to 40 percent at carbon dioxide emission wavelength and 40 to 150 percent at water vapor emission wavelength for hydrogen content increment from 10 to 20 and 20 to 30 percent in syngas mixture. Furthermore, experimental data shows that spectral intensity increases almost 2 to 6 times as firing input increases from 500 W to 1000 W at 250 W intervals for both oxy-syngas and oxy-methane combustion.