Our technicians have addressed the question of the impact of low-NOx burners on boiler operation. The main influencing factors are boiler design and coal quality. Through combustion adjustments, secondary air ratios, and SOFA air ratios, steam temperature parameters in some plants have essentially reached design values, and fly ash combustibles have been significantly reduced. After retrofitting with low-NOx burners, changes in the furnace temperature field will significantly impact the flue gas and steam temperature characteristics at the furnace outlet. This is primarily manifested in the following two aspects:
1. From a combustion perspective, retrofitting boilers with air-staged low-NOx combustion technology results in delayed combustion, upward shifting of the flame center, increased furnace outlet flue gas temperature, and increased boiler superheat and reheat steam temperatures.
2. Retrofitting boilers with air-staged low-NOx combustion technology results in a significant temperature drop in the main combustion zone, resulting in a more uniform temperature distribution within the furnace. Water-wall fouling and slagging are significantly improved, heat absorption by the water-walls is enhanced, and furnace outlet flue gas temperature decreases, leading to lower superheat and reheat steam temperatures. The changes in steam temperature characteristics after boiler low-NOx combustion retrofits are primarily influenced by the two factors mentioned above, with the dominant influence primarily dependent on the boiler design and the coal quality used. Operating conditions of air-staged low-NOx burners at various plants show that, using the designed coal type, increasing the separated overfire air (SOFA) volume reduces the excess air coefficient in the main combustion zone, leading to significant increases in both superheater and reheater temperature rises.
Our technicians have addressed the question of the impact of low-NOx burners on boiler operation. The main influencing factors are boiler design and coal quality. Through combustion adjustments, secondary air ratios, and SOFA air ratios, steam temperature parameters in some plants have essentially reached design values, and fly ash combustibles have been significantly reduced. After retrofitting with low-NOx burners, changes in the furnace temperature field will significantly impact the flue gas and steam temperature characteristics at the furnace outlet. This is primarily manifested in the following two aspects:
1. From a combustion perspective, retrofitting boilers with air-staged low-NOx combustion technology results in delayed combustion, upward shifting of the flame center, increased furnace outlet flue gas temperature, and increased boiler superheat and reheat steam temperatures.
2. Retrofitting boilers with air-staged low-NOx combustion technology results in a significant temperature drop in the main combustion zone, resulting in a more uniform temperature distribution within the furnace. Water-wall fouling and slagging are significantly improved, heat absorption by the water-walls is enhanced, and furnace outlet flue gas temperature decreases, leading to lower superheat and reheat steam temperatures. The changes in steam temperature characteristics after boiler low-NOx combustion retrofits are primarily influenced by the two factors mentioned above, with the dominant influence primarily dependent on the boiler design and the coal quality used. Operating conditions of air-staged low-NOx burners at various plants show that, using the designed coal type, increasing the separated overfire air (SOFA) volume reduces the excess air coefficient in the main combustion zone, leading to significant increases in both superheater and reheater temperature rises.