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Causes and Prevention of Rotary Kiln Deformation

Date:2019-12-23 13:21     writer:admin     Views:

Equipment is the basis of production. Rotary kiln is the central equipment of cement production and one of the key points of equipment management. Rotary kiln is required to be round and straight, but it will be deformed due to various reasons during production, causing bad consequences such as tile heat and falling bricks. Now let's talk about your own opinion on the cause and treatment of the rotary kiln barrel deformation.
 

I. Ways and Causes of Rotary Kiln Deformation


Rotary kiln deformation can be divided into two major types, namely hoop deformation and axial deformation.

For the rotary kiln, the circumferential deformation always exists, but it is required to be less than one thousandth of the kiln diameter, which is normal. Beyond this range, plastic deformation is abnormal. The reasons for the use are in addition to the design and manufacture. They are mainly due to two aspects. The first is the brick-red kiln that is dropped. It will be convex outward or concave inward, and the circumferential deformation will occur. If the red kiln appears under the wheel belt, the cylinder will be recessed by the squeeze of the supporting wheel. The second is that the gap between the belts is too large, and the reinforcing effect of the belts on the barrel is lost. The barrels bulge inward under the action of the supporting rollers passing through the belts.

There are many reasons for the axial deformation of the rotary kiln. Red kiln, temperature difference, improper operation can cause axial deformation. Specifically, it can be divided into the following.

 

1. Improper heating operation
During the heating-up of the kiln, the initial temperature is low. Generally, it is intermittently turned to the kiln. When the temperature of the barrel rises to a certain level, it starts to rotate slowly. The first is to ensure that the kiln lining is uniformly heated. The effect of difference and gravity produces axial bending. If the kiln is not turned according to the regulations during the period, the kiln will have axial deformation.

2. Improper shutdown of the kiln
The operation of stopping the kiln is the opposite of heating. At the beginning, due to the high temperature of the cylinder and the high temperature of the material in the kiln, continuous slow kiln rotation is required. When the temperature of the cylinder gradually decreases, intermittent kiln rotation is performed. After the kiln has a short time and the temperature is reduced, the intermittent kiln is stopped, and the kiln will bend under the action of the temperature difference of the cylinder body and its own gravity, resulting in axial deformation.

3. During the kiln shutdown, do not turn over the kiln for a long time
During the long-term outage of the kiln, one side of the cylinder is exposed to sunlight and the temperature is high, while the other side is too low because it cannot be illuminated. The amount of elongation on one side of the light will be greater than the other, and the kiln will bend. On the other hand, the kiln has a large weight and downward bending is inevitable. If it is not turned over for a long time, plastic deformation will occur, resulting in axial bending.

4. Kiln skin is unstable
The kiln skin is unstable, which will inevitably cause high local temperature, and the circumferential temperature difference of the cylinder is unavoidable. Then, the kiln cylinder will bulge back in the direction of high temperature, causing axial deformation.

5. The idler is off-center
If the centerline of the supporting wheel does not coincide with the centerline of the kiln barrel, the deviation is large, and the axial bending of the kiln is unavoidable, because the kiln has the characteristics of horizontal rigidity and longitudinal flexibility. Restrictions, bending occurs and so on.

 

II. Hazard of barrel deformation


The bending of the large kiln barrel can have various negative effects, which can be listed as follows.
 

1. The deformation of the cylinder is not conducive to the masonry of the brick, especially the annular convex drum and the longitudinal convex drum.

2. It is easy to drop brick red kiln and shorten the life of kiln lining.

3. The tube is bent and deformed, and the center line is misaligned, which causes the neck to run and the power consumption increases.

4. After the cylinder is bent, the operation will cause disturbance, and at the same time, the load on the supporting wheel will change, which will easily cause the bearing shell to heat up.

5. Deformation at the end of the kiln can easily cause head and tail sealing difficulties, pollute the environment, and also affect the life of the seal. In severe cases, it will also endanger the kiln door cover and smoke chamber.

 


 

III. The prevention of barrel deformation


As a rotary kiln for thermal equipment, deformation is inevitable due to the influence of thermal instability. However, deformation 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 relative stability of the kiln skin, so that the difference in temperature of the barrel will be reduced, so as to ensure that the amount of bending of the kiln is within a small range.

2. When the brick red kiln is dropped or the local kiln lining is very thin, the kiln should be stopped to avoid plastic deformation of the cylinder.

3. Start or stop the kiln to perform intermittent or continuous slow-turning kiln according to regulations or operation instructions to avoid kiln deformation due to improper operation.

4. Regularly measure the centerline of the kiln and adjust it in real time according to the situation, so that the kiln can run 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 you find that the head and tail of the kiln are too big, you must plan to deal with it to avoid causing damage to the head and tail.

7. When the amount of slippage of the belt is found to be too large, it is necessary to replace or thicken the pad. If no slippage is found, cool air should be blown into the gap between the pads to reduce the temperature of the drum and the belt Temperature difference, control the temperature difference below 180 ℃.

 

There are many factors that affect the deformation of the rotary kiln barrel. The reasons for the deformation of the barrel are more complicated, often due to multiple reasons. Therefore, the cause should be identified in the preventive measures and the measures are appropriate.

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