Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion
Ammonia (NH3) reactivity in a micro flow reactor with a controlled temperature profile (MFR) is reexamined through species measurements utilizing two heating sources in the MFR: an H2/air flat flame and an electric heater. The maximum wall temperatures (Tw,max) formed in the reactor vary in a range...
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Elsevier
2024-12-01
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| Series: | Fuel Communications |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666052024000256 |
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| author | Kenta Tamaoki Yoshito Ishida Takuya Tezuka Hisashi Nakamura |
| author_facet | Kenta Tamaoki Yoshito Ishida Takuya Tezuka Hisashi Nakamura |
| author_sort | Kenta Tamaoki |
| collection | DOAJ |
| description | Ammonia (NH3) reactivity in a micro flow reactor with a controlled temperature profile (MFR) is reexamined through species measurements utilizing two heating sources in the MFR: an H2/air flat flame and an electric heater. The maximum wall temperatures (Tw,max) formed in the reactor vary in a range of Tw,max = 1100–1400 K. A stoichiometric NH3/air mixture is tested, and exhaust NH3 is detected by a quadrupole mass spectrometer (QMS). Unexpectedly, NH3 is completely consumed at temperatures at least 100 K lower in the H2/air flat flame case compared to the electric furnace case, despite nearly identical conditions of a MFR characteristic residence time estimated by the wall temperature profiles and the convective flow velocity. Considering the non-thermal characteristics of the two heating sources that the H2/air flat flame emits ultraviolet light, whereas infrared light as thermal radiation is emitted within the electric furnace, the possibility of NH3 photolysis in the H2/air flat flame case is discussed based on literature regarding emissions from the H2/air flames, the transmittance of the quartz tube, and the photodissociation of NH3 in the ultraviolet region. When ultraviolet light emitted from the H2/air flat flame passes through the quartz tube and decomposes NH3 into NH2 and H radicals, these produced radicals enhance the growth of OH radicals, resulting in increased NH3 reactivity. These findings suggest the possibility of photolysis-assisted ammonia combustion, which could be an additional method to overcome the low reactivity of NH3. |
| format | Article |
| id | doaj-art-1bcda9540a4041c0be284bcc7e9e398a |
| institution | OA Journals |
| issn | 2666-0520 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
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| series | Fuel Communications |
| spelling | doaj-art-1bcda9540a4041c0be284bcc7e9e398a2025-08-20T01:58:22ZengElsevierFuel Communications2666-05202024-12-012110013010.1016/j.jfueco.2024.100130Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustionKenta Tamaoki0Yoshito Ishida1Takuya Tezuka2Hisashi Nakamura3Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577, Japan; Department of Mechanical Systems Engineering, Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba, Sendai, Miyagi 980-8579, JapanInstitute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577, Japan; Department of Mechanical Systems Engineering, Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba, Sendai, Miyagi 980-8579, JapanInstitute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577, JapanInstitute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577, Japan; Corresponding author.Ammonia (NH3) reactivity in a micro flow reactor with a controlled temperature profile (MFR) is reexamined through species measurements utilizing two heating sources in the MFR: an H2/air flat flame and an electric heater. The maximum wall temperatures (Tw,max) formed in the reactor vary in a range of Tw,max = 1100–1400 K. A stoichiometric NH3/air mixture is tested, and exhaust NH3 is detected by a quadrupole mass spectrometer (QMS). Unexpectedly, NH3 is completely consumed at temperatures at least 100 K lower in the H2/air flat flame case compared to the electric furnace case, despite nearly identical conditions of a MFR characteristic residence time estimated by the wall temperature profiles and the convective flow velocity. Considering the non-thermal characteristics of the two heating sources that the H2/air flat flame emits ultraviolet light, whereas infrared light as thermal radiation is emitted within the electric furnace, the possibility of NH3 photolysis in the H2/air flat flame case is discussed based on literature regarding emissions from the H2/air flames, the transmittance of the quartz tube, and the photodissociation of NH3 in the ultraviolet region. When ultraviolet light emitted from the H2/air flat flame passes through the quartz tube and decomposes NH3 into NH2 and H radicals, these produced radicals enhance the growth of OH radicals, resulting in increased NH3 reactivity. These findings suggest the possibility of photolysis-assisted ammonia combustion, which could be an additional method to overcome the low reactivity of NH3.http://www.sciencedirect.com/science/article/pii/S2666052024000256AmmoniaMicrocombustionCarbon-free fuelPhotolysis |
| spellingShingle | Kenta Tamaoki Yoshito Ishida Takuya Tezuka Hisashi Nakamura Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion Fuel Communications Ammonia Microcombustion Carbon-free fuel Photolysis |
| title | Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion |
| title_full | Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion |
| title_fullStr | Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion |
| title_full_unstemmed | Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion |
| title_short | Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion |
| title_sort | effects of difference in heating sources on ammonia reactivity possibility for photolysis assisted ammonia combustion |
| topic | Ammonia Microcombustion Carbon-free fuel Photolysis |
| url | http://www.sciencedirect.com/science/article/pii/S2666052024000256 |
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