Equipment is the basis of production. Rotary kiln is the central equipment for cement production and one of the key points of equipment management. The rotary kiln is required to be round and straight, but it will be deformed due to various reasons during production, causing adverse effects such as heat of the tile and bricks, and also causing an increase in energy consumption. Now the cement plant manufacturer talks about the reasons and treatment of the deformation of the rotary kiln cylinder.
First, the way and reasons of deformation of rotary kiln
The deformation form of the rotary kiln can be divided into two categories, namely, circumferential deformation and axial deformation.
For rotary kiln, the circumferential deformation always exists, but it is required to be less than one thousandth of the kiln diameter, which is normal. Exceeding this range and producing plastic deformation is not normal. The reason for the use is in addition to design and manufacture. It mainly comes from two aspects. The first is the brick red kiln. After the red kiln, the temperature of the cylinder is very high, the strength of the cylinder is reduced, the part is elongated, and the cylinder is It will be convex or concave inward, and the circumferential deformation will occur. If the red kiln appears under the wheel, the cylinder will be recessed by the compression of the roller. The second is that the wheel gap is too large, and the reinforcing effect of the wheel belt on the cylinder is lost. The cylinder is inwardly convex under the action of the roller of the wheel.
There are many reasons for the axial deformation of the rotary kiln. The red kiln, temperature difference, improper operation, etc. can cause axial deformation. Specifically speaking, it can be divided into the following.
1. Improper heating operation
During the ignition temperature of the kiln, the temperature in the early stage is relatively low, generally intermittent kiln. When the temperature of the cylinder rises to a certain extent, the kiln is continuously and slowly turned. The first is to ensure the kiln lining is evenly heated. The second is to ensure that the kiln is not warmed by the cylinder. The effect of the difference and gravity produces an axial bend. If the kiln is not turned according to the procedure, the kiln will produce axial deformation.
2. Improper shutdown of the kiln
The operation of stopping the kiln is opposite to the temperature rise. At the beginning, due to the higher temperature of the cylinder, the temperature of the material in the kiln is higher, and the continuous kiln needs to be continuously turned. When the temperature of the cylinder is gradually decreased, the batch is turned to the kiln. If the operation is improper, such as continuous rotation After the kiln time is short and the temperature is lowered, the intermittent kiln is stopped. The kiln will bend under the action of the cylinder temperature difference and its own gravity, resulting in axial deformation.
3. During the period of stopping the kiln
During the long-term shutdown of the kiln, one side of the cylinder is exposed to sunlight, the temperature is higher, and the other side is lower due to the inability to illuminate. The side of the light will stretch more than the other side, and the kiln will bend. On the other hand, the kiln has a large self-weight, and it is inevitable to bend downwards. If it does not turn over for a long time, plastic deformation will occur, causing axial bending.
4. Kiln skin instability
The kiln skin is unstable, which will inevitably cause a local temperature to be high. The circumferential temperature difference of the cylinder is unavoidable, and then the kiln cylinder will return to the high temperature direction and cause axial deformation.
5. The wheel is off center
If the centerline of the roller does not coincide with the centerline of the kiln cylinder, the deviation is large, and the axial bending of the kiln is inevitable. Because the kiln has the characteristics of horizontal and vertical, it sinks first under the action of gravity, and then receives the roller. The limitations, the bends are produced, and so on.
Second, the damage of the cylinder deformation
The bending of the large kiln cylinder can have various negative effects, which can be enumerated below.
1. The deformation of the cylinder is not conducive to the masonry of the brick, especially the annular drum and the longitudinal drum.
2. It is easy to drop the brick red kiln and shorten the lining life.
3. The cylinder is bent and deformed, and the center line is misaligned, causing the neck to run and the power consumption is increased.
4. After the cylinder is bent, the operation will cause disturbance, and at the same time, the force of the roller will change, which will easily cause the bearing bush to heat up.
5. Deformation at the end of the kiln is likely to cause difficulty in sealing the head and tail, pollute the environment, and also affect the life of the seal. In severe cases, it will also endanger the kiln door cover and the smoke chamber.
Third, the prevention of cylinder deformation
As a rotary kiln for thermal equipment, deformation is unavoidable due to thermal instability, but it can be controlled by different means to ensure that it operates in a relatively good state. The specific measures can be as follows.
1. Ensure the stability of the raw materials, so as to achieve thermal stability, and achieve relatively stable kiln skin, so that the difference in cylinder temperature will be reduced, so as to ensure that the bending of the kiln is within a small range.
2. When the kiln falls off the brick red kiln or the local kiln lining is very thin, the kiln should be stopped to avoid plastic deformation of the cylinder.
3. The start-and-stop kiln must be intermittently or continuously rotated to the kiln according to the procedures or operation instructions to avoid deformation of the kiln caused by improper operation.
4. According to the situation, the center line of the calibration kiln is measured regularly and adjusted in real time to enable the kiln to operate under better basic conditions.
5. For the adjustment of the kiln, the foundation cannot be left, and the kiln cannot be operated under the condition of leaving the center line.
6. If the kiln head and tail jump is too large, it must be planned to avoid damage to the head and tail.
7. When the amount of wheel slip is found to be too large, the pad should be replaced or thickened. If no slip is found, the cold air should be blown into the pad gap to reduce the cylinder and the belt. The temperature difference is controlled below 180 °C. Wait.
In summary, there are many factors affecting the deformation of the rotary kiln cylinder, which causes the deformation of the cylinder to be more complicated, which is often caused by various reasons. Therefore, the reasons for the prevention measures are correct and the measures are appropriate.