14 reasons for boiler steel pipe burst and preventive measures

14 reasons for boiler steel pipe burst and preventive measures Boiler steel pipe burst refers to the situation where the water-cooled wall tubes, convection tubes, and economizer tubes in the heat exchange surface of the boiler during operation burst under the combined effect of various reasons such as overheating, wear and corrosion, and high-temperature boiler water leaks, causing the boiler to fail to operate normally. Through years of theoretical accumulation and field practice, it is found that boiler pipeline bursts are mainly caused by fourteen reasons. First: The quality of boiler feed water is poor, there is no water treatment the water treatment method is incorrect, and the sewage treatment is not carried out according to relevant regulations, causing scaling or corrosion on the inner wall of the pipeline. The main reason for this situation is that some boiler water is taken from underground, which is high-hardness water, and contains high sulfur and iron. Once the water is improperly treated, it is easy to burst the pipe, resulting in forced shutdown and emergency repairs, which has a great impact on production and life. Second: During the manufacturing, installation, and maintenance of boiler pipelines, stress concentration and mechanical performance degradation will occur at the welds. Pipeline bursts will occur at these key parts of stress concentration and mechanical degradation, which will also cause boiler failures and make it difficult to supply production and life needs. Third: impurities fall into the steel pipe during installation or maintenance of the boiler, causing blockage in the steel pipe, resulting in poor water circulation or destruction. Fourth: the scale falls off the inner wall of the steel pipe, “bridging” the water circulation to a bad state. Fifth: if the water level is too low during the operation of the boiler, the water circulation will also be poor. When this happens, the local temperature of the pipeline will be too high, deforming, and even bursting. Sixth: oil boilers, gas boilers, or coal boilers, due to the incorrect adjustment of the nozzle angle during design and installation, some boiler pipelines will also overheat. Seventh: incorrect ignition and shutdown operations, the furnace tubes are blown by the cold wind, the steel tubes expand and contract too quickly or too frequently, and harmful stress is generated. Eighth: the smoke duct and the firewall of the combustion chamber are damaged, causing the flue gas to short-circuit and cause the heat concentration of the local furnace tubes to burn the furnace tubes. Ninth: corrosion and aging of equipment usually occur in the economizer tubes on the tail heating surface. The reason is acid corrosion caused by too low exhaust temperature or too low feed water temperature. Tenth: The local smoke velocity is too fast. When installing and repairing the heating surface pipes, the pitch of the heating surface steel pipes and the distance between the heating surface pipes and the furnace wall do not meet the design requirements, forming a local smoke corridor between the pipes or between the pipes and the furnace wall, or the local steel pipes are out of the row, causing the heating surface steel pipes to accumulate ash and bridge, causing the local smoke velocity to be too high, thereby increasing the wear and overheating of the steel pipes in this part. Eleventh: Due to careless construction, the furnace wall seal is not strictly sealed according to the construction requirements, so that vortices are formed at the air leakage. In this case, the pipeline will be locally overheated, or the heating will be uneven, and the air leakage will also increase the flue gas flow rate behind, which will harm the tail heating surface. Twelfth: High-temperature operation of steel pipes is also an important reason for boiler pipe bursting. Overheating and over-temperature pipe bursting are due to the decrease in mechanical properties of steel pipes under overheating, and plastic deformation, namely creep cracking, occurs under the action of pressure, resulting in pipe bursting. Thirteenth: The influence of the operating environment can also cause the furnace tube to rupture, such as frequent boiler start and stop, drastic changes in load, improper adjustment of the center of the flame, primary and secondary air scouring of the water-cooled wall tube, rapid cooling of the shutdown, etc., all of which leave hidden dangers for boiler tube explosion. Fourteenth: The boiler heating system pipe network, or the steam condensate pipe network has carbon dioxide corrosion or oxygen corrosion. When oxygen and carbon dioxide are present in the boiler return water system at the same time, the corrosion of the system pipe network steel will be more serious. Carbon dioxide makes the water slightly acidic and destroys the protective film of the pipe. As the oxygen content increases, the carbon steel equipment and pipe network of the heating system will have a large or small ulcer state, which will accelerate the corrosion. As a result, the return water or condensate water will be yellowish, reddish, or even soy sauce-colored, with a high iron ion content and steel pipe perforation. Common steam pipe and condensate pipe corrosion, perforation, and leakage are caused by this reason. This is also the reason why the service life of some newly built boiler carbon steel pipes is only 4-5 years. Six measures to prevent boiler steel pipe explosion To reduce and eliminate the occurrence of pipe explosions and ensure the needs of production and life, the six measures to prevent boiler pipe explosions are as follows: First: Strengthen the management of water treatment and water quality monitoring, add deoxidation and iron removal equipment, and change from primary softening to secondary softening, so that the boiler water meets the national standard and ensures the safe and economical operation of the boiler. Second: Make full use of the maintenance time after the shutdown, and ask the municipal boiler inspection institute and other authoritative institutions to conduct comprehensive internal and external inspections of the boiler, find and deal with problems in time, and ensure the healthy operation of the boiler. Third: Strengthen the management during operation, organize reasonable combustion conditions and appropriate flame centers, eliminate cold wind-blowing furnace tubes, improve measures to prevent wear and corrosion, and carry out reasonable sewage discharge. Fourth: Descale and smoke pipe cleaning in time after shutdown, and do a good job of maintenance. Fifth: Appropriately increase the exhaust temperature (recommended 150-170 degrees Celsius), taking into account safety and energy saving, eliminating energy waste, and avoiding the generation of tail condensate. Sixth: Add highly effective boiler anti-corrosion and anti-scaling agent BF-30a to prevent scale from depositing on the boiler metal surface in water with higher hardness. Post time: Oct-21-2024