The Effects of Coke Parameters and Circulating Flue Gas Characteristics on NOx Emission during Flue Gas Recirculation Sintering Process

Juntao Han, Guofeng Lou, Sizong Zhang, Zhi Wen, Xunliang Liu and Jiada Liu
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Juntao Han: School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, China
Guofeng Lou: School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, China
Sizong Zhang: School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, China
Zhi Wen: School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, China
Xunliang Liu: School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, China
Jiada Liu: School of Energy and Enviromental Engineering, University of Science & Technology Beijing, Beijing 100083, China

Energies, 2019, vol. 12, issue 20, 1-20

Abstract: 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 2 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 2 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%.

Keywords: numerical simulation; flue gas recirculation; coke combustion; NOx emission (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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