{"title":"添加NH3对C2H4热解过程中烟灰颗粒及气态前体形成的影响","authors":"Kai Zhang , Yishu Xu , Ronghao Yu , Jiahui Wu , Xiaobei Cheng","doi":"10.1016/j.combustflame.2025.114324","DOIUrl":null,"url":null,"abstract":"<div><div>The pyrolysis of C<sub>2</sub>H<sub>4</sub>/NH<sub>3</sub> mixtures was conducted in a plug flow reactor (PFR) in the temperature range of 973 K-1373 K. The pyrolysis products, including C<sub>2</sub>H<sub>4</sub>, NH<sub>3</sub>, C<sub>2</sub>H<sub>2</sub>, C<sub>6</sub>H<sub>6</sub> and HCN, were quantified using gas chromatography (GC) and Fourier transform infrared (FTIR) spectroscopy to elucidate the thermal decomposition behavior of C<sub>2</sub>H<sub>4</sub> and NH<sub>3</sub>, as well as the effects of NH<sub>3</sub> on the formation of gaseous soot precursors. The results indicate that both C<sub>2</sub>H<sub>4</sub> and NH<sub>3</sub> conversion increase during co-pyrolysis compared to their individual pyrolysis. Moreover, C<sub>2</sub>H<sub>4</sub> shows a more pronounced promoting effect on NH<sub>3</sub> decomposition. Kinetic analysis reveals that the reactions C<sub>2</sub>H<sub>4</sub> + NH<sub>2</sub> and NH<sub>3</sub> + CH<sub>3</sub> are primarily responsible for the increased conversion of C<sub>2</sub>H<sub>4</sub> and NH<sub>3</sub>, respectively. The effects of NH<sub>3</sub> on soot precursors formation (e.g., C<sub>2</sub>H<sub>2</sub> and C<sub>6</sub>H<sub>6</sub>) exhibit a non-monotonic trend with reaction temperature. Specifically, NH<sub>3</sub> addition promotes soot precursors formation below 1273 K but inhibits it above 1273 K. This trend is determined by the competition between NH<sub>3</sub>-induced enhancement of C<sub>2</sub>H<sub>4</sub> decomposition and the effects of C<img>N interactions. The former consistently promotes the formation of soot precursors, while the latter becomes significantly effective in inhibiting their formation only above 1273 K by removing C atoms from participating in soot precursors formation. This finding is supported by FTIR measurements with a significant increase of HCN being formed at temperature at 1273 K. It should be noted that as the temperature further increases, the concentration of HCN decreases due to its involvement in the formation of N-containing polycyclic aromatic hydrocarbons (NPAHs). Meaningfully, the molecular structure of NPAHs were identified using gas chromatography-mass spectrometry (GC–MS). Notably, existing kinetic mechanisms are unable to satisfactorily predict the quantitative trends of the experimental results, highlighting the need for further mechanism improvement and refinement.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"279 ","pages":"Article 114324"},"PeriodicalIF":5.8000,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Effects of NH3 addition on soot particles and gaseous precursors formation in C2H4 pyrolysis\",\"authors\":\"Kai Zhang , Yishu Xu , Ronghao Yu , Jiahui Wu , Xiaobei Cheng\",\"doi\":\"10.1016/j.combustflame.2025.114324\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The pyrolysis of C<sub>2</sub>H<sub>4</sub>/NH<sub>3</sub> mixtures was conducted in a plug flow reactor (PFR) in the temperature range of 973 K-1373 K. The pyrolysis products, including C<sub>2</sub>H<sub>4</sub>, NH<sub>3</sub>, C<sub>2</sub>H<sub>2</sub>, C<sub>6</sub>H<sub>6</sub> and HCN, were quantified using gas chromatography (GC) and Fourier transform infrared (FTIR) spectroscopy to elucidate the thermal decomposition behavior of C<sub>2</sub>H<sub>4</sub> and NH<sub>3</sub>, as well as the effects of NH<sub>3</sub> on the formation of gaseous soot precursors. The results indicate that both C<sub>2</sub>H<sub>4</sub> and NH<sub>3</sub> conversion increase during co-pyrolysis compared to their individual pyrolysis. Moreover, C<sub>2</sub>H<sub>4</sub> shows a more pronounced promoting effect on NH<sub>3</sub> decomposition. Kinetic analysis reveals that the reactions C<sub>2</sub>H<sub>4</sub> + NH<sub>2</sub> and NH<sub>3</sub> + CH<sub>3</sub> are primarily responsible for the increased conversion of C<sub>2</sub>H<sub>4</sub> and NH<sub>3</sub>, respectively. The effects of NH<sub>3</sub> on soot precursors formation (e.g., C<sub>2</sub>H<sub>2</sub> and C<sub>6</sub>H<sub>6</sub>) exhibit a non-monotonic trend with reaction temperature. Specifically, NH<sub>3</sub> addition promotes soot precursors formation below 1273 K but inhibits it above 1273 K. This trend is determined by the competition between NH<sub>3</sub>-induced enhancement of C<sub>2</sub>H<sub>4</sub> decomposition and the effects of C<img>N interactions. The former consistently promotes the formation of soot precursors, while the latter becomes significantly effective in inhibiting their formation only above 1273 K by removing C atoms from participating in soot precursors formation. This finding is supported by FTIR measurements with a significant increase of HCN being formed at temperature at 1273 K. It should be noted that as the temperature further increases, the concentration of HCN decreases due to its involvement in the formation of N-containing polycyclic aromatic hydrocarbons (NPAHs). Meaningfully, the molecular structure of NPAHs were identified using gas chromatography-mass spectrometry (GC–MS). Notably, existing kinetic mechanisms are unable to satisfactorily predict the quantitative trends of the experimental results, highlighting the need for further mechanism improvement and refinement.</div></div>\",\"PeriodicalId\":280,\"journal\":{\"name\":\"Combustion and Flame\",\"volume\":\"279 \",\"pages\":\"Article 114324\"},\"PeriodicalIF\":5.8000,\"publicationDate\":\"2025-07-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Combustion and Flame\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0010218025003621\",\"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":"Combustion and Flame","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0010218025003621","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}
Effects of NH3 addition on soot particles and gaseous precursors formation in C2H4 pyrolysis
The pyrolysis of C2H4/NH3 mixtures was conducted in a plug flow reactor (PFR) in the temperature range of 973 K-1373 K. The pyrolysis products, including C2H4, NH3, C2H2, C6H6 and HCN, were quantified using gas chromatography (GC) and Fourier transform infrared (FTIR) spectroscopy to elucidate the thermal decomposition behavior of C2H4 and NH3, as well as the effects of NH3 on the formation of gaseous soot precursors. The results indicate that both C2H4 and NH3 conversion increase during co-pyrolysis compared to their individual pyrolysis. Moreover, C2H4 shows a more pronounced promoting effect on NH3 decomposition. Kinetic analysis reveals that the reactions C2H4 + NH2 and NH3 + CH3 are primarily responsible for the increased conversion of C2H4 and NH3, respectively. The effects of NH3 on soot precursors formation (e.g., C2H2 and C6H6) exhibit a non-monotonic trend with reaction temperature. Specifically, NH3 addition promotes soot precursors formation below 1273 K but inhibits it above 1273 K. This trend is determined by the competition between NH3-induced enhancement of C2H4 decomposition and the effects of CN interactions. The former consistently promotes the formation of soot precursors, while the latter becomes significantly effective in inhibiting their formation only above 1273 K by removing C atoms from participating in soot precursors formation. This finding is supported by FTIR measurements with a significant increase of HCN being formed at temperature at 1273 K. It should be noted that as the temperature further increases, the concentration of HCN decreases due to its involvement in the formation of N-containing polycyclic aromatic hydrocarbons (NPAHs). Meaningfully, the molecular structure of NPAHs were identified using gas chromatography-mass spectrometry (GC–MS). Notably, existing kinetic mechanisms are unable to satisfactorily predict the quantitative trends of the experimental results, highlighting the need for further mechanism improvement and refinement.
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