Raw material vertical mills are key grinding equipment in cemento production. Their operational stability directly impacts production efficiency and product quality. However, many enterprises often face air leakage issues in the vertical mill system. This not only increases energy consumption but may also lead to equipment failures, affecting the continuity and reliability of production lines. This article analyzes the causes of air leakage in raw material vertical mills and proposes corresponding solutions.
I. Impact of Air Leakage in Vertical Mills
1.Increased Energy Consumption: Air leakage in the vertical mill system causes heat loss. The internal temperature of the mill decreases. To maintain the required temperature, additional hot air supply is necessary, leading to increased energy consumption.
2.Decreased Output: Air leakage results in the loss of some materials. This reduction in material inside the mill lowers the load, which subsequently decreases production output.
3.Equipment Failures: Prolonged air leakage accelerates the wear of internal components, especially seals and pipes. This shortens equipment lifespan and increases maintenance costs.
4.Decline in Product Quality: Air leakage affects the grinding efficiency of materials, leading to either overly fine or coarse products, which compromises product quality.
II. Causes of Air Leakage in Vertical Mills
1.Aging or Damaged Seals: Seals, such as roller seals and feeder seals, can age or break after long-term operation, causing air leakage.
2.Loose Pipe Connections: If the ventilation pipes between the vertical mill and the dust collector are installed loosely or improperly connected, air leakage may occur.
3.Unreasonable Design of Locking Feeders: Traditional locking feeders, such as segmented wheels with blades, may cause air leakage if their gaps are too large or too small.
4.Inefficient Roller Seal Structure: The current roller seal design is simple and has poor sealing effectiveness. This is especially true for lower seals, where space is limited, making it difficult to ensure effective sealing.
5.Defective Slag Discharge Design: The direct chute from the slag discharge port to the belt conveyor is a major leakage point. The single flap valve used in the original design can easily become jammed by large materials, causing the mill to stop.
III. Solutions for Air Leakage in Vertical Mills
1.Replace Aging Seals: Regularly check and replace aging or damaged seals to ensure effective sealing.
2.Strengthen Pipe Connections: Conduct a thorough inspection of the ventilation pipes to ensure connections are secure and tight, and reinforce any loose connections.
3.Optimize Locking Feeder Design: Implement a material seal at the mill head. Adjust the gaps in the segmented wheels to avoid excessive or insufficient spacing that leads to air leakage.
4.Improve Roller Seal Structure: Change the roller seal to a circular silicone wave seal. This design offers better elasticity and sealing effectiveness, effectively reducing air leakage.
5.Redesign the Slag Discharge Port: Modify the discharge port to a non-powered flap locking valve. This design combines a valve body with a material curtain, using system negative pressure to create a sealed structure, effectively addressing the air leakage issue.
IV. Case Study
In a cement enterprise with a 4500 t/d clinker production line, the raw material system is equipped with a TRM53.4 raw material vertical mill. Due to severe air leakage, the oxygen content at the kiln tail reached 10.3%, and the electrical consumption for the raw material process was 16.5 kWh/t. The electrical consumption for the circulating fan was as high as 8.6 kWh/t, and the output temperature was low, only 45–55°C.
This severely limited the energy-saving needs of the raw material mill. After addressing the air leakage and improving fan efficiency, the enterprise implemented measures such as replacing the locking feeder, upgrading the roller seals, and redesigning the discharge port.
As a result, air leakage significantly decreased, electrical consumption dropped by 3.8 kWh/t, the output temperature increased, and hourly production improved. After these upgrades, the enterprise saved approximately 2.58 million yuan in energy costs annually, achieving significant economic benefits.
V. Conclusion
Air leakage in raw material vertical mills is a complex and critical issue. Enterprises should address this from multiple angles, including design, installation, and maintenance. By optimizing equipment design, enhancing maintenance, and improving sealing effectiveness, companies can effectively reduce air leakage, increase the operational stability of vertical mills, and enhance production efficiency. If you have any questions about improving equipment performance, please feel free to Contacto. Darko is here to provide you with professional solutions and support.
