Characteristics of Combustion and NOx Emission in a 600 MWe Wall-Fired Boiler Under Varying Coal Mill and Burner Damper Configurations

To accelerate China's transition toward providing capacity support and prioritizing electricity generation, detailed research is necessary regarding the continuous peak output of coal-fired boilers during peak periods. However, high-load operation of coal-fired boilers may lead to issues such as NOx emission and increased flue gas temperature. This study conducted industrial experiments on a 600 MWe wall-fired boiler operating under peak conditions (500 MWe), using different pulverized coal mill operating modes. The boiler was optimized by adjusting the damper openings of the burners. Experimental results showed coal powder ignited within 0.2 m of burner outlets, indicating good performance. With the reduction in the damper openings of the burners, the concentration of NOx decreased, and the flue gas temperature gradually dropped, with the maximum temperature differential being 179 degrees C. The ABCEF pulverized coal mill case had high water consumption and flue gas loss, unfavorably affecting economic operation. The ABDEF case delayed temperatures by 100 degrees C, with the lowest NOx concentration at 277 ppm, enhancing environmental friendliness. In addition, the ABCDE case exhibited optimal coal burnout, with 0.838% fly ash carbon content, and the lowest flue gas temperature at 111.49 degrees C, reducing flue gas loss by 5.9% compared to the ABDEF case, showing good economic performance.