What is the kiln skin of a rotary kiln?
Rotary kiln is the main equipment for cement production. The cement rotary kiln is a sloping rotating cylinder placed on several pairs of supporting wheels through several belts, and its inner wall is inlaid with refractory bricks. Raw meal powder is fed into the kiln barrel from the lower end of the kiln tail barrel. Due to the inclination and slow rotation of the kiln barrel, the material produces a tumbling along the circumferential direction and from high temperature to low along the axial direction In the compound movement of the end movement, the raw meal is preheated, decomposed, and fired in the kiln. After firing the cement clinker, it is discharged from the bottom end of the kiln barrel and enters the cooling machine. Fuel is injected from the kiln head and burned in the kiln. The heat emitted heats the raw meal to make the raw meal calcined into clinker. The hot air formed during the exchange with the material enters the kiln system from the kiln feed end The chimney is discharged into the atmosphere. Rotary kiln is mainly composed of kiln barrel, transmission device, support device, wheel block device, kiln head sealing device, kiln tail sealing device, kiln head cover, etc. The cylinder of the cement rotary kiln is a cylinder made of steel plate. In order to protect the cylinder of the rotary kiln, a layer of refractory brick is inlaid on the inside as a kiln lining.
Rotary kiln is a device that integrates fuel combustion, heat exchange, high temperature chemical reaction and conveying material flow. Because the temperature of the gas in the kiln is much higher than the temperature of the material, the high temperature of 1450 ° C is often maintained in the container. Every revolution, the surface of the kiln lining is subjected to periodic thermal shock, the temperature change range is 150-250 ℃, and thermal stress is generated in the range of 10-20mm surface of the kiln lining; the kiln lining also withstands the alternating brickwork caused by rotation Varying axial and radial mechanical stresses, as well as erosion wear of the calcined material; due to the erosion of the silicate melt to the refractory material at the same time, it will cause the refractory material to fall off and make the surface temperature of the kiln body too high Or "Red Kiln". The refractory brick has limited refractoriness and thickness, and it cannot withstand the long-term high-temperature attack and the corrosion of the chemical reaction of the material. The upper layer of clinker, see the firework to call it "kiln skin".
What is the principle of hanging the kiln skin of the rotary kiln incinerator?
The kiln skin is hung according to the characteristics that the material has the adhesive properties when it is calcined in the rotary kiln incinerator and the surface melted refractory brick. The liquid phase appears after the material enters the firing zone, and the liquid phase increases as the temperature rises. When the surface of the refractory bricks of the rotary kiln incinerator melts slightly, with the rotation of the kiln, the clinker with a certain adhesiveness presses the refractory bricks underneath, and absorbs a certain amount of heat from the refractory bricks to make them stick together. A chemical reaction takes place and the first layer of kiln skin is formed as the temperature drops. The kiln skin becomes thicker and thicker as the kiln operating time increases, and the surface temperature of the kiln skin becomes higher and higher. The number of kiln skins adhered and dropped is equal. After smelting, the kiln skin is firm and dense.
