Low NOx combustion and SCR flow field optimization in a low volatile coal fired boiler. (15th August 2018)

• Record Type: Journal Article
• Authors: Liu, Xing; Tan, Houzhang; Wang, Yibin; Yang, Fuxin; Mikulčić, Hrvoje; Vujanović, Milan; Duić, Neven
• Is Part Of: Journal of environmental management. Volume 220(2018)
• Page Start: 30
• Page End: 35
• Publication Date: 2018-08-15
• Subjects: NOx -- Burner -- Coal combustion -- Air staging -- Low volatile coal -- Flow field optimization; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2018.05.009
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Low NO x burner redesign and deep air staging have been carried out to optimize the poor ignition and reduce the NO x emissions in a low volatile coal fired 330 MWe boiler. Residual swirling flow in the tangentially-fired furnace caused flue gas velocity deviations at furnace exit, leading to flow field unevenness in the SCR (selective catalytic reduction) system and poor denitrification efficiency. Numerical simulations on the velocity field in the SCR system were carried out to determine the optimal flow deflector arrangement to improve flow field uniformity of SCR system. Full-scale experiment was performed to investigate the effect of low NO x combustion and SCR flow field optimization. Compared with the results before the optimization, the NO x emissions at furnace exit decreased from 550 to 650 mg/Nm³ to 330–430 mg/Nm³. The sample standard deviation of the NO x emissions at the outlet section of SCR decreased from 34.8 mg/Nm³ to 7.8 mg/Nm³. The consumption of liquid ammonia reduced from 150 to 200 kg/h to 100–150 kg/h after optimization. Highlights: Denitrification applied on a tangentially fired boiler burning low volatile coal. Deep air staging, burner redesign and SCR flow field optimization were combined. NO x at furnace exit decreased to 330–430 mg/Nm³ burning low volatile coal. SCR Velocity profiles were smoothed and optimized based on numerical simulations.