- Time:Sep 05, 2023
1. Solutions to high temperature effects
①Optimize the gas flow in the kiln: change the gas flow distribution or install deflectors and other measures to better discharge and disperse the high-temperature gas near the transition zone.
② Control the materials entering the kiln: By adjusting the feed amount, feed speed and proportion in the kiln, the materials are fully sintered before entering the transition zone.
③ Strengthen the protective measures of the kiln lining: select the kiln lining material with high refractory performance, and carry out appropriate thickness design to enhance its ability to resist high temperature erosion.
2. Coping strategies affected by chemical attack
① Choose refractory materials with good corrosion resistance: choose refractory materials with strong chemical stability and corrosion resistance to reduce the degree of corrosion by chemical substances.
② Control the atmosphere in the kiln: adjust the oxygen content, atmosphere composition and combustion temperature in the kiln, control the generation and concentration of harmful gases, and reduce the erosion of refractory bricks.
③Regularly clean up the accumulated slag and residues in the kiln to reduce its erosion on refractory materials. At the same time, carry out regular inspection and maintenance, repair damaged parts in time, and prolong the service life of refractory materials.
④ Through real-time monitoring of parameters such as temperature, atmosphere and chemical composition, timely adjust the operating conditions of the kiln, maintain a stable combustion and production environment, and reduce the risk of chemical erosion.
3. Solutions for coal injection pipe and fuel change
① Use high-quality coal, reduce the content of sulfur and other harmful components, ash content less than 27%, volatile matter greater than 25%, calorific value greater than 21MJ/kg (greater than 5000 kcal/kg)/, total sulfur less than 3% high-quality coking coal, Gas coal, weakly caking coal, non-caking coal, etc.
② Control the adjustment of the internal and external wind of the coal injection pipe, and monitor the flame shape and length of the coal injection pipe.
It is ideal that the coal injection pipe protrudes 1~1.5 meters beyond the discharge port. In this range, the wind and coal are mixed, the flame is complete, the kiln is clear and easy to see, the operation is easy to control, and the position of the front ring of the knot is also easy to burn.
4. Solutions to the influence of mechanical force
① Use materials with high strength and good thermal expansion resistance to reduce the problems caused by different expansions caused by temperature differences.
② Adjust the gap between the tires to the appropriate width. During the operation of the kiln, regularly check and maintain the tugboat assembly to ensure the coaxiality and stable operation of each set of tugboats.
To sum up, among the methods to reduce the damage of refractory materials in the transition zone, the methods that can be solved through manual intervention include optimizing gas flow, controlling the atmosphere in the kiln, cleaning slag regularly, using high-quality coal, controlling the indicators of materials entering the kiln, and controlling Matching of wind, coal and materials. For those phenomena that are difficult to control in production, adjusting the kiln body refractories in the transition zone is a crucial step to solve the problem.
Considering the poor thermal stability, severe chemical erosion, and the special working conditions in the transition zone of the cement kiln, which are easily affected by fuel and coal injection pipes, a commonly used basic refractory material is magnesium-aluminum spinel refractory bricks.
By optimizing the structure of the refractory material, the magnesia-alumina spinel brick reduces the SiO2 and Fe2O3 that affect the stability to a reasonable range, and improves the corrosion resistance. In addition, during the high-temperature sintering process, spinel can be generated in situ in the brick, and the micro-cracks generated during the reaction process can be used to improve its thermal shock stability and compression resistance. By adjusting the matrix and particles of raw materials, the problem of low soft temperature under original load of ordinary magnesia-alumina bricks is fundamentally solved.
The safe service life of magnesia-aluminum spinel bricks produced by Zhenjin in Huaxin 6500T/D kiln reaches 456 days. Since then, more than 14 Huaxin 5000T/D large kiln transition zones have all been made of zhenjin magnesia-alumina spinel bricks, and the operating cycle has exceeded 12 months. This allows the kiln linings in the transition zone and the firing zone to keep running synchronously.
Each cement kiln is a unique system. To find out the root cause of the problem and solve it sometimes requires the cooperation of multiple parties, so as to achieve twice the result with half the effort in a more efficient way.
