Alleviating gas/particle flow deflection and asymmetric combustion in a 600 MWe supercritical down-fired boiler by expanding its furnace throat space

• Published in: Applied thermal engineering Vol. 123; p. 1201
• Main Authors: Wei, Yanhui, Kuang, Min, Zhu, Qunyi, Ling, Zhongqian, Ti, Shuguang, Li, Zhengqi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier BV 01.08.2017
• Subjects: Asymmetry; Boiler furnaces; Coal-fired power plants; Cold flow; Combustion; Computer simulation; Flow deflection; Furnaces; Gas flow; Mathematical models; Nitrogen oxides; Numerical analysis; Studies
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2017.05.113

Cold-modeling gas/particle flow experiments and numerical simulations on coal combustion were performed for evaluating the furnace throat effect on the flow-field deflection and asymmetric combustion in a 600 MWe supercritical down-fired boiler. At the furnace design setting (CW = 0.529), a severely deflected gas/particle flow field appears, corresponding to a badly asymmetric combustion pattern with poor burnout and high NOx emissions. Shrinking the furnace throat from CW = 0.529 to CW = 0.500 apparently aggravates both the experimental and simulated flow-field deflection and meanwhile deteriorates asymmetric combustion. In contrast, expanding the furnace throat space to CW = 0.558 improves greatly the above problems and the flow-field symmetries are generally acceptable, accompanied by improved burnout rate and lowered NOx emissions. Findings in this work suggest that new down-fired boiler designs should be equipped with a larger furnace throat space under the circumstances with a short upper furnace aggravating the asymmetric upper furnace configuration effect.