Investigation on flame characteristics of oxy-fuel combustion

Md Rafiqul Islam, University of Texas at El Paso

Abstract

Oxy-fuel combustion is currently being considered by the U.S. Department of Energy as a promising technology for efficient carbon capture. This technology could substantially reduce NOx and CO2 emissions. In addition, the implementation of oxy-fuel combustion technology in a power generation system could potentially reduce negative environmental impacts of fossil fuel use. It also encourages the use of reliable and domestic energy sources. The U.S. Department of Energy has made efforts to investigate the performance of a CO2 and H2O diluted oxy-fuel combustion system in a high-pressure combustor. In an effort to better understand and characterize the fundamental flame characteristics of oxy-fuel combustion, this thesis presents the flame length, stability of CH4-O 2/CH4-O2-CO2/ CH4-O 2-CO2-H2O flames, global flame radiation measurements, and flame temperature.^ Lengths of oxy-fuel flames mainly depend on fuel firing input and are affected, although less, by O2 concentration in the fuel-oxidizer mixture. In this study, the stability maps of CH4-O2 were plotted using six different tubular burner diameters, ranging from 1 to 6 mm. The flame from the 1 mm diameter burner tube tended to extinguish, even at lower mass flow rates due to a quenching effect. For larger burner diameters, 2 to 6 mm, the flames tended to flashback. It was also observed that the stability regime increased with an increase in CO2 and H2O concentration in the fuel mixtures. The radiative heat release rates of CH4-O2 flames were greater than CH4-air flames. The radiative heat release rate of CH4-O2 flame was almost constant for the lean flames, yielded F value 4.09%, 8.90% by using solar radiometer and Mark IV radiometer, respectively. Once the equivalence ratio reached more fuel rich conditions, the radiative factor increased as the equivalence ratio increased further. The radiative heat release rates also increased as the percentage of CO2 increased at a constant fuel firing input. The radiative heat release rates of 75%CH4-25%CO2 -O2 and CH4-O2 flames were almost similar at constant firing input. As the concentration of CO2 was increased in the oxidizer, the flame temperature decreased.^

Subject Area

Engineering, Mechanical|Energy

Recommended Citation

Islam, Md Rafiqul, "Investigation on flame characteristics of oxy-fuel combustion" (2011). ETD Collection for University of Texas, El Paso. AAI1503730.
http://digitalcommons.utep.edu/dissertations/AAI1503730

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