Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures
Ammonia is an ideal renewable, carbon-free fuel and hydrogen carrier, which produces nitrogen and water after complete combustion in the presence of oxygen. However, ammonia has low reactivity, slow flame-propagation speed, and carries risks of high nitrogen oxide (NO<i><sub>x</sub>...
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MDPI AG
2023-10-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/13/21/11847 |
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| author | Yongbo Du Siyu Zong Chang’an Wang Yongguan Wang Qiang Lyu Yaodong Da Defu Che |
| author_facet | Yongbo Du Siyu Zong Chang’an Wang Yongguan Wang Qiang Lyu Yaodong Da Defu Che |
| author_sort | Yongbo Du |
| collection | DOAJ |
| description | Ammonia is an ideal renewable, carbon-free fuel and hydrogen carrier, which produces nitrogen and water after complete combustion in the presence of oxygen. However, ammonia has low reactivity, slow flame-propagation speed, and carries risks of high nitrogen oxide (NO<i><sub>x</sub></i>) emissions. Co-firing ammonia with an industrial by-product gas (with CH<sub>4</sub> and CO being the main combustible materials) is a cost-effective and convenient method of improving the combustion characteristics of ammonia, but attention still needs to be paid to the NO<i><sub>x</sub></i> generation. Currently, the research on NO<i><sub>x</sub></i> formation during co-firing of ammonia with other fuel gases is still insufficient. In this study, a high-temperature furnace reaction system was used to investigate the NO<i><sub>x</sub></i> formation and inhibition mechanisms during the combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO mixtures. By varying the ammonia blending ratio, excess air coefficient (<i>α</i>), temperature, residence time, and fuel concentration, the key factors influencing NO<i><sub>x</sub></i> generation and inhibition were further analyzed. The results showed that when <i>α</i> was no less than 1, the production of NO<i><sub>x</sub></i> initially increased and then decreased with an increasing proportion of ammonia in the fuel gas. Within the temperature range of 900 °C to 1500 °C, the amount of NO<i><sub>x</sub></i> generated during the combustion of the mixed gas gradually decreased with the increase in temperature. Under the conditions of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO, the emissions of NO<i><sub>x</sub></i> were higher than those during pure ammonia combustion. |
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| language | English |
| last_indexed | 2024-03-11T11:33:55Z |
| publishDate | 2023-10-01 |
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| series | Applied Sciences |
| spelling | doaj.art-b1023bf398964be7a2025bab268abadf2023-11-10T14:58:56ZengMDPI AGApplied Sciences2076-34172023-10-0113211184710.3390/app132111847Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO MixturesYongbo Du0Siyu Zong1Chang’an Wang2Yongguan Wang3Qiang Lyu4Yaodong Da5Defu Che6School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaChina Special Equipment Inspection and Research Institute, Beijing 100029, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaAmmonia is an ideal renewable, carbon-free fuel and hydrogen carrier, which produces nitrogen and water after complete combustion in the presence of oxygen. However, ammonia has low reactivity, slow flame-propagation speed, and carries risks of high nitrogen oxide (NO<i><sub>x</sub></i>) emissions. Co-firing ammonia with an industrial by-product gas (with CH<sub>4</sub> and CO being the main combustible materials) is a cost-effective and convenient method of improving the combustion characteristics of ammonia, but attention still needs to be paid to the NO<i><sub>x</sub></i> generation. Currently, the research on NO<i><sub>x</sub></i> formation during co-firing of ammonia with other fuel gases is still insufficient. In this study, a high-temperature furnace reaction system was used to investigate the NO<i><sub>x</sub></i> formation and inhibition mechanisms during the combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO mixtures. By varying the ammonia blending ratio, excess air coefficient (<i>α</i>), temperature, residence time, and fuel concentration, the key factors influencing NO<i><sub>x</sub></i> generation and inhibition were further analyzed. The results showed that when <i>α</i> was no less than 1, the production of NO<i><sub>x</sub></i> initially increased and then decreased with an increasing proportion of ammonia in the fuel gas. Within the temperature range of 900 °C to 1500 °C, the amount of NO<i><sub>x</sub></i> generated during the combustion of the mixed gas gradually decreased with the increase in temperature. Under the conditions of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO, the emissions of NO<i><sub>x</sub></i> were higher than those during pure ammonia combustion.https://www.mdpi.com/2076-3417/13/21/11847ammonianitrogen oxideblending combustionformation mechanism |
| spellingShingle | Yongbo Du Siyu Zong Chang’an Wang Yongguan Wang Qiang Lyu Yaodong Da Defu Che Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures Applied Sciences ammonia nitrogen oxide blending combustion formation mechanism |
| title | Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures |
| title_full | Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures |
| title_fullStr | Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures |
| title_full_unstemmed | Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures |
| title_short | Study on Mechanisms of NO<i><sub>x</sub></i> Formation and Inhibition during the Combustion of NH<sub>3</sub>/CH<sub>4</sub> and NH<sub>3</sub>/CO Mixtures |
| title_sort | study on mechanisms of no i sub x sub i formation and inhibition during the combustion of nh sub 3 sub ch sub 4 sub and nh sub 3 sub co mixtures |
| topic | ammonia nitrogen oxide blending combustion formation mechanism |
| url | https://www.mdpi.com/2076-3417/13/21/11847 |
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