The direct rotary calcining kiln
rotary kiln is a steel thin-walled cylinder with a 1%---6% slope mounted on the support. Due to the inclined installation of the cylinder, the material in the kiln moves in the axial direction while being turned in the circumferential direction. Therefore, it slowly flows through the entire cylinder, and undergoes complicated physical and chemical changes to complete the dehydration and decarburization processes. It is discharged from its lower end (also known as the kiln end) and enters the cooling system. The fuel is injected from the low end into the high temperature zone of the kiln. Under the natural or mechanical ventilation of the kiln head, the hot flue gas and the material flow backward through the whole kiln, and finally the dust is discharged into the atmosphere by the chimney. . The technical performance and operation of the rotary kiln largely determine the quality, production and production cost of the calcined kaolin.
Rotary kiln structure composition
1. Rotary kiln structureof
The specificationrotary kiln is expressed by the inner diameter and length of the cylinder. For example, ∮ 2.5m × 38m, it means that the inner diameter of the cylinder is 2.5m and the length of the kiln is 38m.
B, wheel belt
C, roller bearing device
α angle - the angle between the belt and the center of the roller and the vertical line increases with the increase of the angle α. If α is too large, both the reaction force and the contact stress rise. The horizontal thrust of the bearing housing is also increased. If the angle α is too small, the stability of the kiln body is poor when it is rotated. In actual use, α = 30 ° -35 °, usually α = 35 °, in order to increase the friction α can be increased to 45 ° -50 °.
Adjustment of the supporting wheel
From the aspect of maintenance and use, one of the keys to ensuring long-term safe operation of the rotary kiln equipment is to properly adjust the supporting roller.
Purpose: 1. Make the kiln body can normally reciprocate along the axial direction.
2. Maintain the linearity of the axis of the rotary kiln.
3. Thecan beby the load balance of the kiln body
axial movement of the kiln bodycontrolled.
(1)oil adjustment method is
If theto make the kiln body squat, add oil with higher viscosity to increase the friction coefficient. To promote the kiln body; otherwise, add a thinner lubricant.
The contact surface of the wheel or the supporting wheel is bright, indicating that the force is large; the hair is small, and the force of the rust is small.
Main parameters of therotary kiln
slantingkiln slope The degree of kiln slope refers to the inclination of the kiln cylinder relative to the horizontal plane, which is usually expressed by the sine value of this angle. It has a close relationship with the filling rate of the materials in the kiln and the rotation speed of the kiln. However, there is no universally applicable criterion for the appropriate slope, and it is impossible to accurately calculate the factors by considering a mathematical expression comprehensively. Generally, the rotary kiln has a slope of 1% to 6%, and most kiln is 2% to 4%. In the initial period, the rotary kiln has a large slope and a small rotation speed of about 0.5 r/min to 0.75 r/min. It is now preferred to use a smaller slope and a higher rotational speed so that the material in the kiln is better mixed and the heat exchange with the hot gas stream is more uniform and sufficient. And the smaller slope can make the bearing of the roller bearing reasonable, the total speed ratio of the transmission system is reduced, and the higher filling rate is allowed. Practical experience shows that the matching of the rotary kiln slope and filling rate in Table 1-9 is suitable.
The information is as follows (Table 1-10) The correspondence between the diameter and the slope of the rotary kiln is appropriate.
Table 1-9 Correspondence between slope and filling rate of
Table 1-10 Rotary kiln diameter and slope Corresponding relationship