These factors can cause the humidifier tower to burst
Date：2019-07-23 15:55 Source：未知Views:
As a static equipment, the humidifying tower is not affected by the alternating stress, and only bears the compressive stress caused by its own weight on the whole, so it is difficult to crack under general circumstances, but it will burst under special circumstances.
1. The flow wall of atomized water causes the explosion of the humidifying tower
Humidifying tower is the preheater (other places also have use) of high temperature exhaust gas conditioning and cooling thermal technology equipment, has a steel plate welding and become, in high temperature gas, have heat preservation, outside can approximate thought are compared.in the same as the gas temperature, gas conditioning tower is in commonly 300 ° or so, but when the gas spray cooling, wall temperature and the gas temperature decrease at the same time.As a relatively independent equipment, the humidifying tower is fixed with anchor bolts on the lower part and equipped with expansion joints on the upper air inlet pipe, which can freely expand and contract according to different temperatures, including axial and radial directions. The thermal stress can be completely released, so it will not crack itself.However, when the atomization effect of atomized water is poor, and the nozzle direction and position error is large, atomized water will be sprayed to a certain part of the cylinder, and some bad effects will be generated, such as the range of gas temperature reduction decreases, and the cylinder temperature increases;The humidifier tower will wet the bottom, etc.However, the worse situation is the emergence of flow wall phenomenon, which sharply reduces the temperature of the cylinder body at this point, causing its sharp contraction, generating huge tensile stress on the periphery, and cracking will occur in the peripheral weak links such as welding seams, accompanied by a huge brittle sound.The author has encountered several such accidents and began to suspect that it was the quality of welding. However, no abnormality was found in the inspection of the fracture. In the inspection of other aspects, it was found that atomized water wall and spray to the cylinder wall were found, and wet bottom and soup pulp were also found in the humidifying tower.
In order to prevent the occurrence of similar accidents, the following aspects should be solved:
Firstly, ensure the atomization effect of sprinkler head, ensure the appropriate pressure and air pressure of sprinkler head (according to the form of sprinkler head of each unit), ensure the correct installation position and direction, and ensure that water mist can be evenly sprayed in the airflow to avoid the flow wall.Second, the atomization effect of the nozzle should be checked frequently, including the diffusion Angle, the size of fog droplets, and check whether the water vapor pressure in operation is normal;Also often check the external insulation situation, once off, timely repair, reduce due to local tube temperature increase additional stress;The operator should also judge whether the system is normal according to the variation of water consumption and exhaust gas temperature, so as to eliminate the hidden danger of accidents in time.
2. Cracking of humidifying tower caused by local explosion
By gas from the preheater of the gas conditioning tower, or when the stove decomposition furnace combustion of pulverized coal is not sufficient, a large amount of carbon monoxide will flock to the humidifying tower, the combustible gas once exposed to air, and reaches a certain proportion can produce burning explosion, the tremendous impact of the resulting directly impact are compared.in addition, caused a huge to wall shear stress, at this time are compared.in the weld heat affected zone or its weak link will be made, in which the crack.Second, due to the low wind speed in the humidifying tower, if there is no combustion of pulverized coal, it is easy to separate deposition in this (especially during the ignition and heating of the large kiln), once the conditions are mature, it will produce rapid combustion explosion, which also causes the cylinder of the humidifying tower to burst.
In terms of preventive measures, the following are recommended:
Firstly, eliminate deflagration conditions, carefully avoid incomplete combustion of pulverized coal, make ventilation conditions sufficient, and avoid carbon monoxide generation and accumulation;Secondly, eliminate dead Angle, eliminate agglomeration conditions of pulverized coal;Thirdly, do a good job of sealing, such as the nozzle connection, ash discharge mouth of the seal, when found that there are cracks in the humidifier tower, to be timely treatment, reduce or put an end to air access, do not create conditions for defldeflation.
3, other forms of cracking
For humidifiers, there are other forms of cracking, but unlike cracking, they are two concepts.For example, in the manufacturing and installation of the humidifying tower, there are many radial dispositions at the interface, and the welding is not tight and the defects are serious. The shear stress generated by the weight of the humidifying tower and the additional load caused by vibration will cut the welding seam.In addition, there are excessive corrosion caused by cracking, to avoid the way is to ensure that the butt wrong side is not out of tolerance, to ensure the quality of welding.Another case is corrosive cracking, because in the exhaust gas of kiln tail, the material contains alkali and acid oxides in the gas, once in contact with water, stay at a certain corner of the humidifying tower, it will corroded the cylinder, and the steel plate will become thinner and even appear holes, some wind and grass will crack.The way to avoid is to deal with dead space, avoid deposition;Ensure atomization effect and avoid wet bottom flow wall.
The reasons for cracking of humidifying tower are not comprehensive, just for reference.At the same time, it also reminds readers that the carbon monoxide content of kiln tail should be controlled at about 0.5%.In addition, the growth rate of carbon monoxide in kiln tail is generally about 0.1%/min. If it is too fast, it is abnormal and must be analyzed and treated.In addition, the explosion point of carbon monoxide is 11%, which is generally not reached. However, the accumulation of carbon monoxide in a certain place and the air leakage there can promote the formation of explosion conditions, which should be concerned.