气候变化领域集成服务门户(CCPortal): Formation and Reduction of NO2in Fixed Bed Combustion of Coal Char under Oxy-Fuel Conditions: Experimental and Density Functional Theory Analysis

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DOI	10.1021/acs.energyfuels.0c00244
	Formation and Reduction of NO2in Fixed Bed Combustion of Coal Char under Oxy-Fuel Conditions: Experimental and Density Functional Theory Analysis
	Yue S.; Wang C.; Xu Z.; Si T.; Zou C.; Anthony E.J.
发表日期	2020
ISSN	8870624
起始页码	6326
结束页码	6337
卷号	34 期号:5
英文摘要	Nitrogen dioxide (NO2) has been attracting a lot of attention because of its toxicity and potential in contaminating land, air, and water. However, research on NO2 release behavior under oxy-fuel conditions is still insufficient. This paper aims to explore the formation and reduction mechanisms of NO2 during oxy-fuel combustion of char by using both experimental and density functional theory (DFT) methods. Results showed that with the increase of temperature, the energy barrier of the NO oxidation reaction increases, while that of the NO2 reduction reaction decreases. These facts lead to a higher peak concentration of NO and lower NO2 emissions. Because of a larger effect of temperature on the rate constant of the NO2 reduction reaction than that of the NO oxidation reaction, the NO2 concentration decreases dramatically and rapidly even if the temperature increases only slightly. As the temperature increases to above 1273 K, the equilibrium constant of the NO oxidation reaction falls to below 105. That is, the oxidation of NO to NO2 is incomplete and reversible over the temperature range of 1273-1673 K. By contrast, the reduction of NO2 to NO is complete and irreversible over this temperature range. As a result, almost no NO2 is observed at high temperatures. In the presence of H2O, DFT calculations show that the water-gas-shift reaction is less important in contrast to the H2O-carbon reaction, which is consistent with previous research. In this case, NOx emissions under an O2/CO2/H2O atmosphere are lower than those under an O2/CO2 atmosphere. Overall, combined experiments with DFT calculations offer a new approach to study the microcosmic mechanisms of NO2 formation and reduction under oxy-fuel conditions during isothermal combustion of char. Copyright © 2020 American Chemical Society.
scopus关键词	Chemical shift; Coal combustion; Equilibrium constants; Fuels; Nitrogen oxides; Oxidation; Rate constants; Reduction; Water gas shift; Density functional theory methods; Effect of temperature; Fixed-bed combustion; Isothermal combustion; Microcosmic mechanism; Reduction mechanisms; Temperature increase; Water gas shift (WGS) reaction; Density functional theory
来源期刊	Energy and Fuels
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/176908
作者单位	Department of Energy Power and Mechanical Engineering, North China Electric Power University, Baoding, 071003, China; Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
推荐引用方式 GB/T 7714	Yue S.,Wang C.,Xu Z.,et al. Formation and Reduction of NO2in Fixed Bed Combustion of Coal Char under Oxy-Fuel Conditions: Experimental and Density Functional Theory Analysis[J],2020,34(5).
APA	Yue S.,Wang C.,Xu Z.,Si T.,Zou C.,&Anthony E.J..(2020).Formation and Reduction of NO2in Fixed Bed Combustion of Coal Char under Oxy-Fuel Conditions: Experimental and Density Functional Theory Analysis.Energy and Fuels,34(5).
MLA	Yue S.,et al."Formation and Reduction of NO2in Fixed Bed Combustion of Coal Char under Oxy-Fuel Conditions: Experimental and Density Functional Theory Analysis".Energy and Fuels 34.5(2020).