300MW机组锅炉再热器和水冷壁频繁爆漏原因分析及其对策

CAUSE ANALYSIS OF FREQUENT BURST-LEAKAGE OCCURRED ON REHEATER AND WATER-WALL OF 300 MW UTILITY BOILER

针对某发电厂近几年锅炉水冷壁和屏式再热器频繁爆漏事故,分析了造成爆漏的主要原因,认为屏式再热器爆漏主要由超温引起的高温氧化失效而致。经在运行中采取控制煤粉细度、提高管材等级和实施管子外表面喷涂抗高温氧化涂层等措施,减少了爆漏事故的发生次数。水冷壁的管壁减薄则为高温腐蚀所致,采取LF7涂层防护、燃烧器改造和加强壁温监视等措施,防止了事故的发生。

Directing against the troubles of frequent burst -leakage occurred in recent years on water- wall and platen reheater of boilers in one power plant, the main causes resulting in burst-leakage have been analysed. It is believed from analysis that the burst - leakage of platen reheater is mainly due to high - temperature oxidation failure resulted from over - temperature. Through adopting measures in operation, such as controlling the fineness of pulverized coal, heigtening the grade of tube material, applying spray coatings on outer surface of tubes for preventing high - temperature oxidation etc. , the number of occurred burst - leakage troubles has been reduced. The thickness - reducing of water- wall tubes is due to high - temperature corrosion, after taking measures, such as protection by using LF7 coating, retrofitting burners, strengthening wall- temperature monitoring, etc. , occurrence of troubles has been prevented.