The clinker calcining ring of rotary kiln is divided into front ring and back ring. So how to prevent the rotary kiln ring?
1. Optimize the ingredients scheme
When ring formation often occurs in rotary kiln, the raw material mixing scheme should be optimized or changed. Proper increase of KH or n rate and decrease of solvent mineral content are beneficial to prevent ring formation.
2. Reduce harmful ingredients brought into the original fuel
In the process of clinker calcination, the harmful components in raw materials are decomposed, vaporized and volatilized successively. They condense and adhere to the surface of raw materials at the end of kiln with low temperature, and enter the kiln together with raw materials. In this way, the alkali-sulfur ring is easily formed at the back of the kiln.
According to the production experience, when the clinker MgO > 4.8%, the clinker liquid phase volume can be greatly increased, the liquid phase viscosity decreases, the firing range becomes narrow, the kiln skin increases, and the floating kiln skin thickens.
Sometimes, although the MgO in clinker is less than 4.0%, due to the fusing effect of R2O, the liquid phase volume of clinker suddenly increases greatly at a certain temperature or a certain position in the kiln, and the viscosity decreases greatly. As a result, the clinker will quickly bond in the temperature region or a certain position in the kiln to form a clinker ring.
3. Control fineness of pulverized coal to ensure full combustion of pulverized coal
Pulverized coal with high ash content, coarse fineness and large moisture content has high ignition temperature, slow combustion speed, long black head, easy to produce incomplete combustion, relatively concentrated coal ash subsidence, and easy to form clinker ring.
Therefore, it is necessary to control the fineness and moisture of pulverized coal as far as possible, improve the ignition temperature of pulverized coal, and ensure the full combustion of pulverized coal to prevent the formation of clinker ring. In addition, the unstable feeding amount of coal makes the temperature in the kiln rise and fall, which is also easy to produce ring formation.
4. Control the shape of the flame to ensure that the wind and coal are evenly mixed
In the process of clinker calcination, it is necessary to move the coal injection pipe often, change the position of the ignition point, adjust the burner, so as to control the shape of the flame, to ensure that the wind and coal mix evenly and have a certain flame length.
5. Improve the fast rotation rate of kiln
Under the premise of ensuring uniform feeding and coal feeding and strengthening material pre-firing, the kiln speed should be accelerated as far as possible. The thin block firing and long flame firing system should be adopted to improve the quick rotation rate of the kiln and prevent the kiln from forming rings. In addition, the three teams should unify the operation methods and stabilize the thermal system of the firing system.
