“…Under the minimum turndown ratio, the CO emission also increased drastically because of the poor turbulent intensity. By decreasing the turndown ratio, the NO emission level gradually increased, because the residence time at the hot combustion zone is increased by decreasing the fuel and oxidizer velocity. − At the minimum and maximum turndown ratios, the measured NO emission levels are 106 and 88 ppm, respectively. 11 NO emission level versus turndown ratio for the 0.03 MW oxy−fuel combustor.…”
Section: Resultsmentioning
confidence: 99%
“…Ditaranto et al − showed that oxy−fuel combustion increases thermal efficiency and has potential for NO x emission reduction. They also showed that flame length and NO x emission are sensitive to air leaks into the combustion chamber.…”
Emission characteristics of the 0.03 MW oxy−fuel combustor have been experimentally investigated under
a wide operating range of velocity and quarl angle. To simulate the NO emission characteristics of industrial
oxy−fuel furnaces, we mixed 3% nitrogen by supplied oxygen with pure oxygen. When a quarl is not fitted,
the flame length decreased with increasing inlet fuel or oxidizer velocity, mainly because of the increase in
turbulent intensity. In the case of the high-speed injection of fuel or oxidizer without a quarl, NO emission
levels decrease because high-speed injection enhances the entrainment of product gas to the flame zone as
well as decreases the overall combustion residence time. When a quarl is fitted, the flame length increases
with expanding quarl angle because of the decrease in turbulent intensity. The NO emission level increases
with expanding quarl angle because both the entrainment of product gas is prevented and the overall combustion
residence time is increased with the installation of a quarl.
“…Under the minimum turndown ratio, the CO emission also increased drastically because of the poor turbulent intensity. By decreasing the turndown ratio, the NO emission level gradually increased, because the residence time at the hot combustion zone is increased by decreasing the fuel and oxidizer velocity. − At the minimum and maximum turndown ratios, the measured NO emission levels are 106 and 88 ppm, respectively. 11 NO emission level versus turndown ratio for the 0.03 MW oxy−fuel combustor.…”
Section: Resultsmentioning
confidence: 99%
“…Ditaranto et al − showed that oxy−fuel combustion increases thermal efficiency and has potential for NO x emission reduction. They also showed that flame length and NO x emission are sensitive to air leaks into the combustion chamber.…”
Emission characteristics of the 0.03 MW oxy−fuel combustor have been experimentally investigated under
a wide operating range of velocity and quarl angle. To simulate the NO emission characteristics of industrial
oxy−fuel furnaces, we mixed 3% nitrogen by supplied oxygen with pure oxygen. When a quarl is not fitted,
the flame length decreased with increasing inlet fuel or oxidizer velocity, mainly because of the increase in
turbulent intensity. In the case of the high-speed injection of fuel or oxidizer without a quarl, NO emission
levels decrease because high-speed injection enhances the entrainment of product gas to the flame zone as
well as decreases the overall combustion residence time. When a quarl is fitted, the flame length increases
with expanding quarl angle because of the decrease in turbulent intensity. The NO emission level increases
with expanding quarl angle because both the entrainment of product gas is prevented and the overall combustion
residence time is increased with the installation of a quarl.
“…An advantage of this technology is its potential to reduce nitric oxides (NO x ) emissions. Ditaranto et al [4][5][6] investigated NO x emissions from oxy-fuel flames without CO 2 dilution, as it is used in glass melting industry for instance. The authors observed that NO x emissions are especially influenced by air leaks and residual N 2 present in either natural gas or oxygen stream.…”
An experimental study on turbulent non-premixed jet flames is presented with focus on CO 2 -diluted oxy-fuel combustion using a coflow burner. Measurements of local temperatures and concentrations of the main species CO 2 , O 2 , CO, N 2 , CH 4 , H 2 O and H 2 were achieved using the simultaneous line-imaged Raman/Rayleigh laser diagnostics setup at Sandia National Laboratories. Two series of flames burning mixtures of methane and hydrogen were investigated. In the first series, the hydrogen molar fraction in the fuel was varied from 37 to 55 %, with a constant jet exit Reynolds number Re Fuel of 15,000. In the second series the jet exit Reynolds number was varied from 12,000 to 18,000, while keeping 55 % H 2 molar fraction in the fuel. Besides local temperatures and concentrations, the results revealed insights on the behaviour of localized extinction in the near-field. It was observed that the degree of extinction increased as the hydrogen content in fuel was decreased and as the jet Reynolds number was increased. Based on the distribution of the temperature, a fully burning probability index able to quantify the degree of extinction along the streamwise coordinate was defined and applied to the present flame measurements. A comparison of measured conditional mean of mass fractions and laminar flame calculations underlined the significant level of differential diffusion in the near-field that tended to decrease farther downstream. The results also showed high local CO levels induced by the high content of CO 2 in the oxidizer and flame products. A shift of maximum flame temperature was observed toward the rich side of the mixture fraction space, most likely as a consequence of reduced heat release in the presence of product dissociation. Main characteristics of laser Raman scattering measurements in CO 2 -diluted oxy-fuel conditions compared to air-diluted conditions are also highlighted. Most data, including scalar fluctuations and conditional statistics are available upon request.
“…[15,16] Sautet et al measured turbulent flow field velocities in laboratory-scale oxy-fuel flames using the laser Doppler anemometry technique. [17] The Raman/Rayleigh technique was applied successfully for temperature measurement in an oxy-fuel laboratory-scale flame. [18] However, in industrially relevant oxyfuel combustion, these measurement techniques are facing further challenges that are limiting their application.…”
Section: Introductionmentioning
confidence: 99%
“…In principle, non‐invasive laser‐based measurement techniques like Rayleigh, Raman, coherent anti‐Stokes Raman scattering (CARS), laser Doppler anemometry and laser‐induced fluorescence techniques are basically qualified for such measurement problems . Sautet et al measured turbulent flow field velocities in laboratory‐scale oxy‐fuel flames using the laser Doppler anemometry technique . The Raman/Rayleigh technique was applied successfully for temperature measurement in an oxy‐fuel laboratory‐scale flame .…”
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