{"title":"富氧燃烧下重焦油中氮元素转化途径的 ReaxFF 模拟","authors":"","doi":"10.1016/j.joei.2024.101837","DOIUrl":null,"url":null,"abstract":"<div><p>Heavy tar is a crucial intermediate product during coal combustion. To explore the transformation pathway of N atoms in heavy tar under oxy-coal combustion, a comprehensive molecular model of heavy tar with typical N-containing functional groups was constructed. Different temperatures and chemical equivalence ratios were set for the oxy-coal combustion. The ReaxFF was employed to study various products' distribution and molecular numbers. The reaction network among different precursors and NO<em>x</em> was extracted, and the NO to N<sub>2</sub> conversion mechanism was summarized. The results indicated that, like char combustion, the proportion of heavy tar gradually declined, the proportion of light tar and organic gas first rose and then gradually declined, and the proportion of inorganic gas continuously rose during heavy tar combustion. As the temperature increased, the proportion of cyanide precursors decreased, while the proportion of amine precursors and NO<em>x</em> increased. The oxidation of N-containing intermediates became more intense as the O<sub>2</sub> content rose, but this oxidation effect was inhibited, and the NO<em>x</em> generation was reduced as the O<sub>2</sub> content further increased. NO could bond with NH<sub><em>i</em></sub>, HNO, CN, and activate NO, decomposing to produce N<sub>2</sub>O, and N<sub>2</sub>O reacted with H radical to produce N<sub>2</sub>.</p></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":null,"pages":null},"PeriodicalIF":5.6000,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"ReaxFF simulations on the transformation pathway of nitrogen elements in the heavy tar under oxy-coal combustion\",\"authors\":\"\",\"doi\":\"10.1016/j.joei.2024.101837\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Heavy tar is a crucial intermediate product during coal combustion. To explore the transformation pathway of N atoms in heavy tar under oxy-coal combustion, a comprehensive molecular model of heavy tar with typical N-containing functional groups was constructed. Different temperatures and chemical equivalence ratios were set for the oxy-coal combustion. The ReaxFF was employed to study various products' distribution and molecular numbers. The reaction network among different precursors and NO<em>x</em> was extracted, and the NO to N<sub>2</sub> conversion mechanism was summarized. The results indicated that, like char combustion, the proportion of heavy tar gradually declined, the proportion of light tar and organic gas first rose and then gradually declined, and the proportion of inorganic gas continuously rose during heavy tar combustion. As the temperature increased, the proportion of cyanide precursors decreased, while the proportion of amine precursors and NO<em>x</em> increased. The oxidation of N-containing intermediates became more intense as the O<sub>2</sub> content rose, but this oxidation effect was inhibited, and the NO<em>x</em> generation was reduced as the O<sub>2</sub> content further increased. NO could bond with NH<sub><em>i</em></sub>, HNO, CN, and activate NO, decomposing to produce N<sub>2</sub>O, and N<sub>2</sub>O reacted with H radical to produce N<sub>2</sub>.</p></div>\",\"PeriodicalId\":17287,\"journal\":{\"name\":\"Journal of The Energy Institute\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.6000,\"publicationDate\":\"2024-09-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of The Energy Institute\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1743967124003155\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of The Energy Institute","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1743967124003155","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
摘要
重焦油是煤炭燃烧过程中的重要中间产物。为了探索煤炭富氧燃烧时重焦油中 N 原子的转化途径,我们构建了一个具有典型含 N 官能团的重焦油综合分子模型。设定了富氧燃烧的不同温度和化学当量比。利用 ReaxFF 研究了各种产物的分布和分子数。提取了不同前驱物与 NOx 之间的反应网络,并总结了 NO 到 N2 的转化机理。结果表明,与焦炭燃烧一样,在重焦油燃烧过程中,重焦油的比例逐渐下降,轻焦油和有机气体的比例先上升后逐渐下降,无机气体的比例持续上升。随着温度的升高,氰化物前驱体的比例下降,而胺前驱体和氮氧化物的比例上升。随着 O2 含量的增加,含 N 中间体的氧化作用更加强烈,但随着 O2 含量的进一步增加,这种氧化作用受到抑制,NOx 的生成量减少。NO 可以与 NHi、HNO、CN 和活化 NO 结合,分解生成 N2O,N2O 与 H 自由基反应生成 N2。
ReaxFF simulations on the transformation pathway of nitrogen elements in the heavy tar under oxy-coal combustion
Heavy tar is a crucial intermediate product during coal combustion. To explore the transformation pathway of N atoms in heavy tar under oxy-coal combustion, a comprehensive molecular model of heavy tar with typical N-containing functional groups was constructed. Different temperatures and chemical equivalence ratios were set for the oxy-coal combustion. The ReaxFF was employed to study various products' distribution and molecular numbers. The reaction network among different precursors and NOx was extracted, and the NO to N2 conversion mechanism was summarized. The results indicated that, like char combustion, the proportion of heavy tar gradually declined, the proportion of light tar and organic gas first rose and then gradually declined, and the proportion of inorganic gas continuously rose during heavy tar combustion. As the temperature increased, the proportion of cyanide precursors decreased, while the proportion of amine precursors and NOx increased. The oxidation of N-containing intermediates became more intense as the O2 content rose, but this oxidation effect was inhibited, and the NOx generation was reduced as the O2 content further increased. NO could bond with NHi, HNO, CN, and activate NO, decomposing to produce N2O, and N2O reacted with H radical to produce N2.
期刊介绍:
The Journal of the Energy Institute provides peer reviewed coverage of original high quality research on energy, engineering and technology.The coverage is broad and the main areas of interest include:
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The journal''s coverage reflects changes in energy technology that result from the transition to more efficient energy production and end use together with reduced carbon emission.