Affected by changes in the coal market

maintaining stable combustion and low pollutant emissions under inferior coal combustion conditions has become an urgent key technical issue for power generation companies.. This paper takes a 1 000 MW ultra-supercritical boiler as the research object

and constructs the combustion organization of inferior coal based on Airejet burners and XCL burners. Numerical simulation studies indicate that

compared to the design coal

when actually firing low-quality coal with an ash content of 26% and a calorific value of 17.5 MJ/kg

NOx emissions at the furnace outlet increased significantly by approximately 15%. For suppressing NOx formation in the main combustion zone

the excess air coefficient at the burner nozzles is successively reduced to 0.9

0.85

0.8

and 0.75. While this creates a progressively stronger reducing atmosphere that curtails NOx generation

it hinders the ignition and combustion stability of the low-quality coal. Results from refined air distribution adjustments demonstrate that appropriately increasing the oxygen content at the bottom-layer XCL burners while lowering the excess air coefficients at the middle- and top-layer Airejet burners can maintain low NOx emission concentrations at the furnace outlet

while ensuring stable and efficient combustion of the low-quality coal. In summary

refined air distribution adjustments for the 1 000 MW ultra-supercritical boiler can simultaneously enhance combustion stability and reduce NOx emissions when firing low-quality coal.