1. The combustion is not properly adjusted, so that the flame stretches or deflects, causing long-term over-temperature at local of superheater and reheater.
2. The harmful elements in fuel make the flue gas side of the superheater and reheater produce high temperature corrosion , so the tubes are damaged.
3. Chemically supervision is not strict, the water supply quality is not qualified , the steam-water separating unit is poor, so the tube of the superheater scales and is damaged.
4. During start and stop of the boiler, the tube wall temperature is not sufficiently monitored and not adjusted properly, so the tube is over heated.
5. The repairing is not proper, for example, the welding quality is not qualified, the low-quality metal materials are misapplied, thus causing the welding not to withstand the high temperature and the tube to explode.
6. The soot blowing device was not properly installed and operated, so the tube was damaged by blowing.
7. The superheater and reheater have been operated under super temperature and are damaged by flying soot
8. The soot is blocked at the superheater and reheater, so that the local temperature rises.