Predictions of NOx/N2O emissions from an ultra-supercritical CFB boiler using a 2-D comprehensive CFD combustion model--颗粒学报PARTICUOLOGY

Ji, J., Cheng, L., Wei, Y., Wang, J., Gao, X., Fang, M., & Wang, Q. (2020). Predictions of NOx/N2O emissions from an ultra-supercritical CFB boiler using a 2-D comprehensive CFD combustion model. Particuology, 49, 77-87. https://doi.org/10.1016/j.partic.2019.04.003

Predictions of NO_x/N₂O emissions from an ultra-supercritical CFB boiler using a 2-D comprehensive CFD combustion model

Jieqiang Ji ^a, Leming Cheng ^a *, Yangjun Wei ^a, Junfeng Wang ^b, Xinyu Gao ^b, Mengxiang Fang a, Qinhui Wang ^a

a State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
b Harbin Boiler Co., Ltd., Harbin 150040, China

10.1016/j.partic.2019.04.003

Volume 49, April 2020, Pages 77-87

Received 24 April 2018, Accepted 17 April 2019, Available online 26 June 2019, Version of Record 26 February 2020.

E-mail: lemingc@zju.edu.cn

Highlights

• A 2-D CFD combustion model was developed for an ultra-supercritical CFB boiler.

• An NO_x/N₂O sub-model was introduced to predict NO_x/N₂O emissions.

• The effects of excess air and secondary air ratio and height were assessed.

Abstract

NO_x and N₂O emissions from an ultra-supercritical circulating fluidized bed (CFB) boiler were predicted using a two dimensional (2-D) comprehensive computational fluid dynamics (CFD) combustion model. This model was developed from a three dimensional model for a supercritical CFB boiler previously constructed by our group. Based on an analysis of the NO_x and N₂O conversion processes in a CFB boiler, the primary formation and destruction reactions were introduced into the 2-D model and coupled. The resulting model was validated using data from the Baima 600 MW supercritical CFB boiler, and then applied to a 660 MW ultra-supercritical CFB boiler. The effects of excess air, the secondary air (SA) to (primary air (PA) plus SA) ratio and the SA injection height on NO_x and N₂O emissions were investigated. The results show that a higher excess air volume increases both NO_x and N₂O emissions, while increasing the SA/(PA + SA) ratio somewhat reduces both the NO_x and N₂O concentrations. On the basis of the results of this work, optimal locations for SA injection ports so as to lower NO_x and N₂O emissions are recommended.

Graphical abstract

Keywords

NO_x/N₂O emissions; 2-D comprehensive combustion model; Circulating fluidized bed; Ultra-supercritical

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