How to protect and maintain cement kiln coating

      The kiln coating of cement rotary kiln is formed by clinker or dust from liquid phase or semi-liquid phase to solid. It is the main component structure of cement rotary kiln and plays an irreplaceable role in cement production. Cement rotary kiln kiln coating The falling off will greatly reduce the overall performance of the cement rotary kiln equipment. Therefore, maintaining the cement kiln coating is the most important thing.

    1. Hang the kiln coating

    Under normal circumstances, it takes a long time to hang the kiln coating. During the process of hanging the kiln coating, the kiln coating is required to gradually thicken, and the speed should not be too fast, so as not to hang loose kiln coating. When hanging the kiln coating, it is required that the kiln body is regular and intact, the ellipticity is normal, the kiln operation is stable, and the number of times of starting and stopping the kiln should be minimized.

     When hanging the kiln coating, it is required that the composition of raw material and pulverized coal should be stable and appropriate, adapt to the kiln temperature, and the flame position and temperature field should be kept stable, so as to form a stable melt with appropriate quantity and viscosity. It is required that the kiln material and the tree bricks are compatible with each other, which is beneficial for the kiln material to adhere to the brick surface and penetrate into the brick moderately, so that the kiln coating exists stably on the brick body.

      When starting to hang the kiln coating, the feeding rate is 65%~70% of the normal, and the kiln speed is appropriately slowed down. When the kiln material is close to the burning zone, the wind and coal should be increased appropriately to make the surface of the refractory brick "sweat", but not "burn". After the kiln material reaches the firing zone, it is necessary to ensure that it is cooked, but it must not be burned in a large fire, and the grain size should be controlled to be small and uniform. The clinker is as large as a walnut, and as small as a peanut, and the small particles account for more than 80% of the clinker, which can be rolled flexibly. Gradually increase the feeding in the future, and it will be completely volatilized and normal by the 9th shift.

      If the kiln coating cannot be hung according to normal operation, it is necessary to find out the cause of the problem and take targeted measures to solve it. From the perspective of refractory materials, the lower limit of the temperature range of hanging kiln coating is the "sweating" temperature of refractory bricks, and the upper limit of the temperature is the "burning flow" temperature of dense skin. From the perspective of cement clinker, the lower limit of the hanging kiln coating temperature range is the temperature at which the kiln material starts to granulate, and the upper limit of the temperature is the temperature at which the kiln material granules are obviously coarse. The intersection of the two intervals (the part that overlaps with each other) is the temperature range of the hanging kiln coating.

      In general, the reason why the kiln coating cannot be hung is that the temperature range of the kiln coating is too narrow or the temperature range does not exist. Therefore, if the sweating temperature of the refractory material is too high, it is necessary to add substances that are conducive to clinker adhesion when making bricks. For example, phosphate bricks rely on the addition of clay to obtain kiln-hanging properties similar to clay bricks. If the clinker granulation temperature is too low, it is necessary to increase the aluminum rate or silicon rate. For example, when changing from phosphate bricks to magnesia bricks, increasing the aluminum rate of clinker solves the problem of hanging kiln coating. If the problem has already occurred, it is impossible to replace the refractory material, and it is too late to adjust the value of the clinker ratio, and the operation needs to be changed. For example, if necessary, the method of forced cooling of the kiln body by blowing air can be adopted, and the kiln coating can be hung by gradually increasing the cooling air volume. If timely measures are taken, a longer service life can still be obtained after the kiln coating is hung.

      2. Maintenance of kiln coating

      Hanging up the kiln coating is only the first step in long-term safe operation. More importantly, it is to protect the coating and create conditions for high-quality, high-yield, and long-term safe operation. The measures to maintain the kiln coating are:

      (1) Stable hot work system, keep the fast turn rate above 85%.

      (2) Control the shape of the flame so that it does not brush the kiln coating.

      (3) Avoid large fires and top fires, and strictly prohibit burning or yellowing of materials to ensure that the clinker particles are fine and uniform, with small particles of 5-20 mm accounting for more than 80%, tumbling flexibly, and slight dust rising into the cooling machine.

      (4) If it is found that the kiln coating is not good, it should be repaired in time.

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