TY - JOUR
T1 - Simultaneously achieving flame stability enhancement and nitric oxide emission reduction in a small-scale burner using rare-earth composite oxide catalytic coatings
AU - Li, Fan
AU - Ren, Shoujun
AU - Xu, Junchao
AU - Jiang, Liqiao
AU - Yang, Haolin
AU - Wang, Xiaohan
AU - Chu, Huaqiang
N1 - Publisher Copyright:
© 2026 The Combustion Institute. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
PY - 2026/11
Y1 - 2026/11
N2 - Achieving low nitrogen oxide emissions in high-efficiency fuel conversion is a crucial objective in combustion science. This study systematically investigates the effects of inert Al2O3 and catalytic Y2O3-BaO-ZrO2 coatings on the combustion stability and pollutant emission characteristics of premixed methane/air flames confined within a narrow channel. Experimental measurements, including flame extinction limits, spatially resolved OH chemiluminescence intensities, axial flame temperature profiles, and CO/NO concentrations in exhaust gases, were conducted across a wide operating range. Results demonstrated that the quenching distance of bare stainless-steel wall exhibited a pronounced nonlinear dependence on wall temperature. In contrast, the quenching date for Y2O3-BaO-ZrO2 catalytic coating were reduced linearly by up to 71.8% and 85.4% as wall temperature increasing to 1073 K at stoichiometric and fuel-lean conditions. Although Al2O3-coated wall yielded the higher peak OH chemiluminescence intensity in flame cores across all equivalence ratio than the case of Y2O3-BaO-ZrO2, the latter promoted significantly higher peak flame temperature and markedly extended high-temperature reaction zones, strongly confirming superior combustion enhancement by wall modification with rare-earth composite oxide catalytic coatings. Crucially, the Y2O3-BaO-ZrO2 coating enabled synergistic control of pollutant emissions: at a-4 mm channel width, catalytic CO conversion exceeded 95% on average, while NO emissions were suppressed to near-zero levels under fuel-rich conditions. In situ diffuse reflectance infrared Fourier transform spectroscopy further revealed accelerated CH4 oxidation and NO decomposition over the Y2O3-BaO-ZrO2 surface, suggesting the possible involvement of a Mars-Van-Krevelen-type redox pathway driven by lattice oxygen mobility and surface oxygen vacancy regeneration.
AB - Achieving low nitrogen oxide emissions in high-efficiency fuel conversion is a crucial objective in combustion science. This study systematically investigates the effects of inert Al2O3 and catalytic Y2O3-BaO-ZrO2 coatings on the combustion stability and pollutant emission characteristics of premixed methane/air flames confined within a narrow channel. Experimental measurements, including flame extinction limits, spatially resolved OH chemiluminescence intensities, axial flame temperature profiles, and CO/NO concentrations in exhaust gases, were conducted across a wide operating range. Results demonstrated that the quenching distance of bare stainless-steel wall exhibited a pronounced nonlinear dependence on wall temperature. In contrast, the quenching date for Y2O3-BaO-ZrO2 catalytic coating were reduced linearly by up to 71.8% and 85.4% as wall temperature increasing to 1073 K at stoichiometric and fuel-lean conditions. Although Al2O3-coated wall yielded the higher peak OH chemiluminescence intensity in flame cores across all equivalence ratio than the case of Y2O3-BaO-ZrO2, the latter promoted significantly higher peak flame temperature and markedly extended high-temperature reaction zones, strongly confirming superior combustion enhancement by wall modification with rare-earth composite oxide catalytic coatings. Crucially, the Y2O3-BaO-ZrO2 coating enabled synergistic control of pollutant emissions: at a-4 mm channel width, catalytic CO conversion exceeded 95% on average, while NO emissions were suppressed to near-zero levels under fuel-rich conditions. In situ diffuse reflectance infrared Fourier transform spectroscopy further revealed accelerated CH4 oxidation and NO decomposition over the Y2O3-BaO-ZrO2 surface, suggesting the possible involvement of a Mars-Van-Krevelen-type redox pathway driven by lattice oxygen mobility and surface oxygen vacancy regeneration.
KW - CO/NO emission control
KW - Catalytic coating
KW - Flame-wall interaction
KW - Natural gas combustion
KW - Quenching distance
UR - https://www.scopus.com/pages/publications/105047835797
U2 - 10.1016/j.combustflame.2026.115245
DO - 10.1016/j.combustflame.2026.115245
M3 - Article
AN - SCOPUS:105047835797
SN - 0010-2180
VL - 293
JO - Combustion and Flame
JF - Combustion and Flame
M1 - 115245
ER -