Methods for handling abnormal issues in rotary kilns
As an important equipment in many industrial productions, rotary kilns may encounter various abnormal problems during operation. Timely and accurate handling of these issues is crucial for ensuring normal production, improving product quality, and reducing equipment wear and tear. The following will provide a detailed introduction to two common abnormal problems and their solutions in rotary kilns.
1、 Ring formation of rotary kiln
Ring formation is one of the common problems in the operation of rotary kilns, usually forming a hard ring in a specific part of the kiln. （1） Reasons for the formation of circles
The content of harmful components in raw materials is too high, such as potassium, sodium, chlorine, etc. These components evaporate at high temperatures and circulate and accumulate in the kiln, which can easily lead to the formation of rings.
For example, some ores contain high levels of potassium feldspar or sodium feldspar, which will produce low melting point compounds during the calcination process, gradually adhering to the kiln wall and forming rings.
Improper operation is also an important reason for the formation of loops. If the temperature control inside the kiln is unstable and the local temperature is too high, the material is prone to sintering and forming rings in the high-temperature zone. In addition, an unreasonable ratio of coal to air and poor ventilation can also cause coal ash to accumulate in the kiln, promoting the growth of rings.
（2） Methods for handling loops
Hot burning method
When the agglomeration is not too severe, the temperature inside the kiln can be appropriately increased to soften and detach the agglomerates at high temperatures. The specific operation is to increase the fuel supply and raise the flame temperature, but attention should be paid to controlling the heating rate to avoid causing excessive thermal shock to the kiln lining. At the same time, strengthen the ventilation inside the kiln to timely remove the detached agglomerates from outside the kiln.
For example, when dealing with mild ring formation in a rotary kiln of a cement plant, by increasing the kiln head temperature by 50 ℃ and maintaining it stable for 4 hours, the ring formation was successfully softened and detached, and normal production was restored. Mechanical cleaning method
For more severe knots, mechanical cleaning is more effective. Special tools such as scrapers and spray guns can be used to insert from the kiln head or tail into the kiln to remove or crush the agglomerates. When performing mechanical cleaning, it is necessary to stop the operation of the kiln and take safety precautions.
The rotary kiln of a certain steel plant once experienced severe ring formation. Mechanical cleaning method was used to stop feeding and fuel supply first. After the kiln body cooled down, the operator entered from the kiln head and gradually removed the ring formation using an air pick. After a day of hard work, the ring formation problem was successfully solved.
2、 Rotary kiln Red kiln
Red kiln refers to the phenomenon of local high temperature or even redness on the surface of the rotary kiln body, which is a very dangerous situation.
（1） The reasons for the emergence of the Red Kiln
Damaged kiln lining
Long term high temperature, chemical erosion, and mechanical wear may cause the kiln lining to become thinner and fall off, exposing the kiln body directly to high temperature environments, resulting in red kilns. For example, if the kiln lining has been used for too long, exceeding its design life, or if it is subjected to strong impact and friction from materials during the operation of the kiln body, resulting in damage to the kiln lining.
Deformation of kiln body
Due to improper installation, uneven settlement of the foundation, or long-term high temperature effects, the kiln body may deform, resulting in uneven stress on the kiln lining, which can easily cause local damage and lead to red kiln.
（2） The treatment method of Red Kiln
Emergency kiln shutdown
Once the red kiln phenomenon is discovered, the operation of the rotary kiln should be stopped immediately to avoid further damage to the kiln body. At the same time, quickly cut off the fuel supply and reduce heat input.
If a ceramic factory discovers a red kiln in the rotary kiln during the production process, the on duty operator decisively takes emergency measures to stop the kiln, avoiding the escalation of the accident.
Cooling treatment
After stopping the kiln, the red kiln should be promptly cooled by spraying water to reduce the temperature of the kiln body. But it is important to control the water spray speed and volume to avoid cracking of the kiln body due to sudden temperature drops. During the cooling process, it is necessary to closely monitor the temperature changes of the kiln body to ensure the cooling effect.
After a red kiln occurred in the rotary kiln of a certain lime plant, the method of uniform water spray cooling was adopted. After 8 hours of continuous cooling, the temperature of the kiln body returned to normal.
For abnormal issues with rotary kilns, operators need to closely monitor the equipment's operating status, promptly identify problems, and take correct and effective measures according to specific situations. At the same time, it is necessary to strengthen the daily maintenance and management of equipment, regularly inspect the condition of kiln lining, kiln body and other components, optimize operating processes, prevent abnormal problems from occurring, and ensure the long-term stable operation of the rotary kiln.
