Effect of secondary air on NO emission in a 440 t/h circulating fluidized bed boiler based on CPFD method--颗粒学报PARTICUOLOGY

Liu, H., Sun, H., Bi, Y., Jia, C., Zhang, L., Li, Y., . . . Wang, Q. (2023). Effect of secondary air on NO emission in a 440 t/h circulating fluidized bed boiler based on CPFD method. Particuology, 83, 18-31. https://doi.org/10.1016/j.partic.2023.02.002

Effect of secondary air on NO emission in a 440 t/h circulating fluidized bed boiler based on CPFD method

Hongpeng Liu ^a, Haiwen Sun ^a, Ye Bi ^a, Chunxia Jia ^a *, Lei Zhang ^b, Yanlong Li ^c, Hong Qin ^a, Qing Wang ^a

a Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, School of Energy and Power Engineering, Northeast Electric Power University, Jilin, 132012, China
b Department of Chemical & Biological Engineering, University of British Columbia, Vancouver, V6T1Z3, Canada
c Northeast Branch of Huadian Electric Power Research Institute Co., Ltd, Shenyang, 110000, China

10.1016/j.partic.2023.02.002

Volume 83, December 2023, Pages 18-31

Received 22 October 2022, Revised 25 January 2023, Accepted 6 February 2023, Available online 17 February 2023, Version of Record 11 March 2023.

E-mail: jiachunxia_215@neepu.edu.cn

Highlights

• Field experiment were restored by Computational Particle Fluid Dynamics numerical simulation.

• The combustion and NO_x formation in the furnace under the operating conditions were analyzed.

• The effect of the secondary air ratio on combustion and NO_x generation were predicted.

• Combined use of air classification and central air distribution can improve combustion stability and inhibit NO generation.

Abstract

The 440 t/h circulating fluidized bed boiler was numerically simulated by the Computational Particle Fluid Dynamics (CPFD) method. The combustion characteristics of circulating fluidized bed boiler and the effect of secondary air on NO emission were investigated. The full-scale three-dimensional model of a 440 t/h circulating fluidized bed boiler was established. The rationality of the grid was validated by the experimental data of material layer resistance. The accuracy of the simulation was validated by measuring the temperature of each measuring point in the dense phase area. The combustion conditions in the furnace under different setting modes were simulated. The effects of secondary air rates on NO formation in fluidized bed were predicted. The results show that when the secondary air rate increases to 27%, the proper secondary air rate has a positive effect on the inhibition of NO generation, and the proper strengthening of the central air supply will improve the permeability of the secondary air and make the combustion more uniform and stable. When the secondary air rate increases to 33%, excessive improvement of air classification and central air distribution will affect the stability of circulating fluidized bed operation. Therefore, air classification and strengthening of central air supply can be used together to inhibit the generation of NO.

Graphical abstract

Keywords

Circulating fluidized bed; Low nitrogen combustion; Computational particle fluid dynamics (CPFD); Numerical simulation; Secondary air

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