Accident Handling 42: What are the causes of tube failure in the superheater of a circulating fluidized bed boiler?
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What are the causes of tube failure in the superheater of a circulating fluidized bed boiler?
1. Wear causes the superheater tube walls to thin out. 2. The quality of the steam is substandard, which causes scaling inside the pipes and ultimately leads to local bulging and cracking. 3. Over-temperature causes creep deformation of the tube wall, leading to tube rupture. 4. Tube rupture due to substandard tube material.
There are two reasons for tube failure in superheaters: 1. Tube failure due to prolonged overheating. When the superheater tubes are exposed to elevated temperatures over an extended period, the mechanical strength of the metal material decreases, and the creep rate increases; as a result, the tubes expand and eventually rupture. 2. Short-term overheating and pipe rupture: Due to foreign objects blocking the pipes, unstable boiler combustion, and other reasons, heat transfer within the pipes deteriorates, causing local temperatures to rise sharply. The temperature increase exceeds the maximum allowable limit for metal materials, which leads to the pipes rupturing from overheating.
Reasons such as overheating, corrosion, and wear – the specific situation needs to be analyzed!
I. Over-temperature； II. The soda parameters are not up to standard, with scaling occurring; a typical example is an excess level of SiO2.