CFD Investigation on Air-Staged Combustion Characteristics of Deep Peak Shaving Wall-Fired Burner Boilers

In alignment with China's ambitious goals of reaching peak carbon emissions and achieving carbon neutrality, stringent load peak regulations are being enforced for coal-fired power generation. This underlines the significance of deploying deep load peaking strategies in coal-fired units. The current research focus is on wall-fired boilers operating under ultra-low loads of 600 MWe. It delves into the flow dynamics, combustion characteristics, component concentration field, and NOx emission characteristics under varying air coefficients in the primary combustion zones (alpha). The findings suggest the formation of a consistently high-temperature region in the primary combustion zone, where temperatures surpass 1500 K. The middle burner exhibits superior combustion stability compared to the bottom burner. As alpha diminishes, several changes occur. The flow field intensity in the primary combustion zone lessens, the ignition distance contracts, and the O2 concentration in this area drops. This engenders a reducing atmosphere characterized by low O2 and high CO levels, which hampers the formation of NOx. At alpha = 0.95, the NO concentration peaks, with the primary generation mechanism being temperature-driven. At this juncture, the NO concentration at the furnace flue gas outlet is 287.36 mg/m3.