Trends of the Flow-Field Deflection and Asymmetric Combustion in a 600 MWe Supercritical Down-Fired Boiler with Respect to the Furnace Arch’s Burner Span

The asymmetric upper furnace configuration effect (mainly relied on the short upper furnace) and unreasonable burner designs (mainly related to the burner location and burner span on furnace arches) are taken as potential major factors favoring the asymmetric combustion formation in down-fired boilers. To confirm the burner span’s role in this aspect, numerical simulations on coal combustion in a 600 MWe supercritical down-fired boiler that suffered from severe flow-field deflection and asymmetric combustion were carried out at three burner span settings (i.e., CS = 0.387, 0.441, and 0.495), plus full-load industrial-size measurements at the boiler’s design setup CS = 0.441. The boiler’s design setup shows a badly asymmetric combustion performance with poor burnout and high NOx emissions, corresponding to its severely deflected gas/particle flow field. Shortening the burner span to CS = 0.387 greatly improves the flow-field deflection and asymmetric combustion, resulting in a burnout increase and NOx redu...