Local overheating-a factor affecting the thermoeconomy and reliability of coal-fired utility boilers and its some improvement countermeasures

摘要

In modern high-capacity utility boilers,superheaters and reheaters are the key components.A tube panel of superheater or reheater consists of a number of tube loops.The reliability of boiler operation relies on the wall metallic temperature of these tube loops.Many factors result in the outlet steam temperature of some tube loops greatly overstepping the mean temperature.This often leads the metallic temperature of these tubes exceeds their safety limit.Recently,not only in domestic high-capacity boilers but also in imported boilers,the overheating accidents frequently take place in China,and some powr plants are forced to operate in low parameter.