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Boiler tube rupture refers to the situation in which, during operation, the water wall tubes, convection tubes, and economizer tubes in a boiler develop cracks due to a combination of factors such as overheating, wear, and corrosion. This leads to the leakage of hot boiler water, preventing the boiler from functioning properly. Through years of theoretical research and extensive field experience, we have identified fourteen main causes of boiler pipeline ruptures. 01 Issues related to water supply quality and treatment methods: Poor quality of boiler feed water, lack of water treatment or incorrect treatment methods, as well as failure to carry out proper drainage according to relevant regulations, can lead to scaling or corrosion on the inner walls of the pipelines. The main reason for this is that some boiler water comes from underground sources, with a hardness level as high as 5 mmol/L; it is therefore high-hardness water. Additionally, it contains high levels of sulfur and iron. If the water is not treated properly, pipe explosions can easily occur, forcing the shutdown of the boiler for repairs, which has a significant impact on production and daily activities. 02 Defects in pipeline manufacturing, installation, and maintenance: During the manufacturing, installation, and maintenance of boilers, stress concentration and a decline in mechanical properties occur at the welds. Pipeline ruptures can happen at these areas where stress concentration and mechanical weakness exist, which in turn can cause failures in the boiler and make it difficult to meet the needs of production and daily life. 03 Blockage inside the pipes: During installation or maintenance of the boiler, impurities fall into the pipes, causing blockages that result in poor water circulation or even a complete disruption of it. 04 Scale detachment affects water circulation. When scale on the inner walls of pipes detaches, it forms bridges that disrupt the normal flow of water. 05 Low water level: If the water level is too low while the boiler is in operation, poor water circulation occurs. This situation can lead to excessively high temperatures in certain sections of the pipes, causing them to deform or even burst. 06 Nozzle angle issue: In oil boilers, gas boilers, or coal boilers, improper adjustment of the nozzle angle during design and installation can also lead to overheating in some of the boiler pipelines. 07 Improper operation of starting up and shutting down the furnace: Incorrect procedures for starting up and shutting down the furnace can expose the furnace tubes to cold air currents, as well as cause rapid or frequent thermal expansion and contraction of the tubes, resulting in harmful stresses. 08 Flue and combustion chamber failures: Damage to the fire barriers in the flue and combustion chamber allows smoke to flow in a short circuit, resulting in concentrated heat on certain sections of the furnace tubes and their subsequent damage. 09 Corrosion and Aging Corrosion-induced pipe failure and equipment aging-induced pipe failure. It generally occurs in the economizer tubes on the heated side at the tail, due to acidic corrosion caused by excessively low flue gas temperatures or low feedwater temperatures. 10 Abnormal local flue gas velocity: The local flue gas velocity is too high. During the installation and maintenance of the heating surface tubes, the spacing between these tubes, as well as the distance between the tube arrays and the furnace wall, do not meet the design specifications. This results in the formation of local flue gas channels between tube arrays or between tube arrays and the furnace wall, or it causes some tubes to deviate from their proper position, leading to dust accumulation and the formation of bridges among the tubes. As a result, the local flue gas velocity increases, thereby increasing wear and overheating of the tubes in those areas. 11 Poor sealing of the furnace wall: Due to careless construction, the sealing areas of the furnace wall were not properly sealed as required, which resulted in vortices forming at the leakage points. This can lead to localized overheating of the pipelines or uneven heating. Additionally, the air leakage increases the flow rate of the smoke gases downstream, posing a threat to the heating surfaces at the rear end. 12 High-temperature operation: The operation of pipes at high temperatures is also a significant cause of boiler tube failures. Tube failure due to overheating occurs when the mechanical properties of the pipes decline under excessive temperature conditions; under pressure, the pipes undergo plastic deformation, resulting in creep cracks that ultimately lead to tube failure. 13 Impact of operating environment: The conditions of the operating environment can also cause the furnace tubes to crack. Factors such as frequent starting and stopping of the boiler, sharp changes in load, improper adjustment of the flame’s position, erosion of the water-cooled wall tubes by primary and secondary air currents, and the effects of rapid cooling during shutdown all pose risks of tube failure in the boiler. 14 Pipeline Corrosion: Carbon dioxide corrosion or oxygen corrosion may occur in the pipelines of boiler heating systems or steam condensation systems. When both oxygen and carbon dioxide are present in the boiler return water system, it accelerates the corrosion of the steel components in these pipelines. Carbon dioxide renders the water slightly acidic, thereby destroying the protective layer on the pipes. An increase in oxygen content leads to the formation of ulcers of varying sizes in the carbon steel equipment and pipelines of heating systems, further accelerating corrosion. As a result, the return water or condensate takes on a yellow, red, or even soy sauce-colored appearance; the iron ion concentration increases, and the steel pipes may develop holes. This is the reason for the common corrosion, perforation, and leakage in steam pipes and condensate pipes. This is also why the service life of carbon steel pipes in some newly installed boilers is only 4-5 years, which means that the condensate pipelines need to be replaced every 4-5 years. Excessive iron content in the boiler return water not only causes the \"red water\" phenomenon in the boiler water but also leads to corrosion beneath the iron oxide scale. It also leads to the rapid formation of phosphatic scale in the boiler. Iron oxide scale has very poor thermal conductivity, and the heat transfer efficiency of this scale layer is significantly different from that of the boiler tubes, which severely hinders heat transfer. This results in excessively high local temperatures on the heat transfer surfaces, leading to a decrease in metal strength and posing a threat to the safety of the boiler. It can also cause the boiler tubes to deform, resulting in tube failures.