- Time:Jun 27, 2022
The life of the rotary kiln lining is a problem that every plant will pay attention to, and the main factors affecting its life include: the working environment and conditions of the kiln lining, the production conditions, the stability of the production process and equipment, the selection and matching of refractory materials and The correct use of kiln lining or not. Therefore, in order to prolong the life of the rotary kiln lining, we must pay attention to the following key points. 1. The s...
The life of the rotary kiln lining is a problem that every plant will pay attention to, and the main factors affecting its life include: the working environment and conditions of the kiln lining, the production conditions, the stability of the production process and equipment, the selection and matching of refractory materials and The correct use of kiln lining or not.
Therefore, in order to prolong the life of the rotary kiln lining, we must pay attention to the following key points.
1. The sticking and protection of kiln skin
Whether the kiln skin on the brick lining of the firing zone and the transition zone on both sides is stable is a decisive condition affecting the service life of the kiln lining. The kiln skin is a clinker protective layer formed by adhering to the surface of the bricks in the kiln firing zone and part of the transition zone. Its normal thickness is about 150-230mm, and its composition is basically the same as that of clinker. Stable and high-quality kiln skin is a prerequisite for extending the service life of refractory bricks.
(1) First of all, it is necessary to control the quality of the raw meal to ensure that the chemical composition of the raw meal entering the kiln is stable and appropriate, and the fineness is qualified.
The usual practice is to use the normal production raw meal or the raw meal with a slightly higher saturation ratio to hang the kiln skin to ensure that there is a suitable liquid phase amount, and the standard control is "difficult to burn but not divergent, easy to burn but not to block".
(2) Secondly, it is necessary to stabilize the operation of the kiln and control the maturity of the clinker.
Neither under-burning or running raw meal, nor over-sintering large pieces, should keep the clinker fine and uniform. During the kiln hanging period, the output is maintained at 70% of the load, and the kiln speed is slightly slower than normal.
(3) In addition, during the initial feeding operation, the operation rhythm should be controlled.
After a long time of drying the kiln, the enrichment of coal ash in the system will affect the clinker composition. Starting with a large amount of material and a fast kiln speed can prevent the material (mixed with more coal ash) from over-sintering or agglomerating. In normal production, the working conditions should be kept stable, the kiln skin should be protected, and the system should be avoided frequently. In addition, it is necessary to frequently observe whether the kiln skin is normal, and strictly monitor the surface temperature of the kiln body in the firing zone and transition zone.
If it is found that the kiln skin is too thin, even exposed bricks, and the surface temperature of the kiln body is too high, the kiln skin must be repaired to achieve normal. In order to ensure the smooth operation of the kiln skin during the supplementary hanging, the feeding of raw meal should be appropriately reduced when necessary, and the hourly output and shift output during the supplementary hanging period should not be assessed.
2. Improve the operation rate of the kiln system
The frequent failures of the kiln system in the production process will make the kiln start and stop more frequent, the kiln temperature will converge, and the cold and heat will alternate, which will often cause the kiln skin to fall off, the kiln bricks to crack or peel off a layer. The more times it happens, the more easily the kiln bricks are damaged. When the kiln skin falls off, such as the kiln brick masonry is not strong or the brick is thin, it is easy to be taken down together, resulting in a red kiln accident. The higher the continuous operation rate of the kiln, the longer the life.
In the event of abnormal failures such as blockage of the preheater, the surface temperature of the lining of the kiln will drop from about 1400 °C to 100 to 200 °C in more than 10 hours; If the heat is repeated repeatedly, the structure of the kiln brick will be damaged, and it will be easy to burst and peel, which will affect its service life.
To reduce the number of unplanned kiln shutdowns, the following suggested actions may be considered:
(1) Strengthen the maintenance of mechanical and electrical equipment, and strengthen the inspection of posts.
Especially during the replacement of refractory bricks, all equipment, process systems, process pipes, etc. must be thoroughly inspected. If problems are found, they must be dealt with immediately to provide the best guarantee for the stable operation of the kiln system in the next operation cycle.
(2) Pay attention to the quality of maintenance, and each sub-item in the maintenance project has a person in charge.
After the project is overhauled, a stand-alone test run is carried out first, so that when problems are found, they can be dealt with in a timely manner. At the same time, there are strict checks on the quality of incoming accessories and materials to ensure the operation rate and integrity rate of the equipment.
3. Stabilize the thermal system of the rotary kiln
When the rotary kiln is running, if the thermal system is unstable, it will cause the lining of the kiln to be hot and cold, and the kiln skin will collapse for a long time.
Therefore, the following corresponding measures must be taken:
(1) "Five stability guarantees one stability": that is, the composition of the raw meal entering the kiln is stable, the feeding amount into the kiln is stable, the fuel composition is stable, the fuel feeding amount is stable and the equipment operation is stable. Only by realizing the "five stability" can we ensure the stability of the thermal system of the kiln system.
(2) The reasonable matching of wind, coal, material and kiln speed, the four are mutually linked and mutually restrained, in order to ensure the stability of the thermal system.
The coordination between air, coal, material and kiln speed should not only be reasonable in quantity, but also pay attention to the quality of the mixture, so that the pulverized coal burns quickly, the material absorbs heat quickly, and the kiln speed is the most appropriate, so that it can be fully utilized. Advantages of precalciner kilns.
(3) The multi-channel coal injection pipe must be adjusted reasonably and dynamically according to different coal qualities and different kiln conditions.
On the premise of ensuring the good clinker sintering condition, depending on the clinker granulation, flame shape, cylinder temperature, kiln tail temperature and pressure, etc., adjust the air ratio of axial flow and swirling air to ensure the shape and length of the flame. Appropriate, smooth and powerful, so that the kiln skin is stable and not washed. Always pay attention to the change in the quality of coal powder entering the kiln and its impact on the shape of the flame. If the moisture content of the coal is high and the black burner becomes longer, the coal injection pipe should be withdrawn a little, the secondary air temperature should be increased, the burning speed should be increased, and the kiln skin should be protected to the maximum extent.
(4) Reasonably adjust the operation of the grate cooler to ensure stable secondary and tertiary air temperatures, and at the same time take into account the synchronous operation with the rotary kiln to achieve the purpose of stabilizing the thermal system.
