Abstract: In the commissioning stage of the 600-MW supercritical CFB boiler, the startup burner upper duct burnout may occur due to the overheating of the startup burner upper duct and, the damage of the refractory layer lined in the duct inner surface. Aiming at this phenomenon, the root cause of the fault is analyzed and the corresponding methods for improvement are proposed, such as optimizing the structure of the duct, lengthening and strengthening the inner cylinder of the burner, increasing the strength of the duct and improving the refractory material performance. The implementation of these methods has effectively prevented the occurrence of the fault, which ensures the ignition and startup of the boiler and can provide reference for the startup burner design of subsequent supercritical CFB boilers and the retroffing of the existing CFB boiler.

Key words: 600 MW, supercritical CFB boiler, ignition duct, improvement