The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process
The new process of flue gas recirculation, which reduces coke consumption and reducing NOx emissions, is now extensively used. Compared with traditional sintering, the characteristics of circulating flue gas and coke parameters significantly affect the combustion atmosphere and coke combustion effic...
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| Format: | Article |
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MDPI AG
2019-10-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/12/20/3828 |
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| author | Juntao Han Guofeng Lou Sizong Zhang Zhi Wen Xunliang Liu Jiada Liu |
| author_facet | Juntao Han Guofeng Lou Sizong Zhang Zhi Wen Xunliang Liu Jiada Liu |
| author_sort | Juntao Han |
| collection | DOAJ |
| description | The new process of flue gas recirculation, which reduces coke consumption and reducing NOx emissions, is now extensively used. Compared with traditional sintering, the characteristics of circulating flue gas and coke parameters significantly affect the combustion atmosphere and coke combustion efficiency. Based on the actual complex process of sintering machine, this study proposes a relatively comprehensive one-dimensional, unsteady mathematical model for flue gas recirculation research. The model encompasses NOx pollutant generation and reduction, as well as SO<sub>2</sub> generation and adsorption. We focus on the effects of cyclic flue gas characteristics on the sintering-bed temperature and NOx emissions, which are rarely studied, and provide a theoretical basis for NOx emission reduction. Simulation results show that during sintering, the fuel NOx is reduced by 50% and 10% when passing through the surface of coke particles and CO, respectively. During flue gas recirculation sintering, the increase in circulating gas O<sub>2</sub> content, temperature, and supply-gas volume cause increased combustion efficiency of coke, reducing atmosphere, and NOx content in the circulating area; the temperature of the material layer also increases significantly and the sintering endpoint advances. During cyclic sintering, the small coke size and increased coke content increase the char-N release rate while promoting sufficient contact of NOx with the coke surface. Consequently, the NOx reduction rate increases. Compared with the conventional sintering, the designed flue gas recirculation condition saves 3.75% of coke consumption, i.e., for 1.2 kg of solid fuel per ton of sinter, the amount of flue gas treatment is reduced by 21.64% and NOx emissions is reduced by 23.59%. Moreover, without changing the existing sintering equipment, sintering capacity increases by about 5.56%. |
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| id | doaj.art-f4b99182d4a04c778f2ddc445987b465 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-11T12:51:16Z |
| publishDate | 2019-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-f4b99182d4a04c778f2ddc445987b4652022-12-22T04:23:13ZengMDPI AGEnergies1996-10732019-10-011220382810.3390/en12203828en12203828The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering ProcessJuntao Han0Guofeng Lou1Sizong Zhang2Zhi Wen3Xunliang Liu4Jiada Liu5School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, ChinaSchool of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, ChinaSchool of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, ChinaSchool of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, ChinaSchool of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, ChinaSchool of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, ChinaThe new process of flue gas recirculation, which reduces coke consumption and reducing NOx emissions, is now extensively used. Compared with traditional sintering, the characteristics of circulating flue gas and coke parameters significantly affect the combustion atmosphere and coke combustion efficiency. Based on the actual complex process of sintering machine, this study proposes a relatively comprehensive one-dimensional, unsteady mathematical model for flue gas recirculation research. The model encompasses NOx pollutant generation and reduction, as well as SO<sub>2</sub> generation and adsorption. We focus on the effects of cyclic flue gas characteristics on the sintering-bed temperature and NOx emissions, which are rarely studied, and provide a theoretical basis for NOx emission reduction. Simulation results show that during sintering, the fuel NOx is reduced by 50% and 10% when passing through the surface of coke particles and CO, respectively. During flue gas recirculation sintering, the increase in circulating gas O<sub>2</sub> content, temperature, and supply-gas volume cause increased combustion efficiency of coke, reducing atmosphere, and NOx content in the circulating area; the temperature of the material layer also increases significantly and the sintering endpoint advances. During cyclic sintering, the small coke size and increased coke content increase the char-N release rate while promoting sufficient contact of NOx with the coke surface. Consequently, the NOx reduction rate increases. Compared with the conventional sintering, the designed flue gas recirculation condition saves 3.75% of coke consumption, i.e., for 1.2 kg of solid fuel per ton of sinter, the amount of flue gas treatment is reduced by 21.64% and NOx emissions is reduced by 23.59%. Moreover, without changing the existing sintering equipment, sintering capacity increases by about 5.56%.https://www.mdpi.com/1996-1073/12/20/3828numerical simulationflue gas recirculationcoke combustionnox emission |
| spellingShingle | Juntao Han Guofeng Lou Sizong Zhang Zhi Wen Xunliang Liu Jiada Liu The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process Energies numerical simulation flue gas recirculation coke combustion nox emission |
| title | The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process |
| title_full | The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process |
| title_fullStr | The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process |
| title_full_unstemmed | The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process |
| title_short | The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process |
| title_sort | effects of coke parameters and circulating flue gas characteristics on nox emission during flue gas recirculation sintering process |
| topic | numerical simulation flue gas recirculation coke combustion nox emission |
| url | https://www.mdpi.com/1996-1073/12/20/3828 |
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