(1) Design of grinding table speed and grinding roller size of vertical roller mill
The material falling to the center of the grinding table is moved by the centrifugal force to the edge of the grinding table under the action of the rotation of the grinding table. In the process, the grinding roller uniformly distributed in the circumferential direction of the grinding table is pulverized by multiple forces.
The speed at which the material moves toward the edge of the table determines the number of times the material is subjected to the grinding roller; the number of times the force is applied greatly determines the fineness of the finished product.
The speed at which the material moves toward the edge of the table also determines the amount of material that passes through the table per unit time, affecting the production time of the vertical mill
. The physical properties of the material will affect its speed of movement on the table.
The rotational speed of the grinding table greatly affects the moving speed of the material on the grinding table. Therefore, the rotation speed of the grinding table should be combined with the characteristics of the material to balance the fineness and output of the finished product.
Vertical grinding of high-fine limestone powder, first of all to ensure the fineness of limestone powder, under this premise, consider the grinding efficiency, vertical roller mill output, stabilize the bed, and run smoothly. The grinding wheel speed and the size of the matching grinding rolls are determined around these core design issues.The high-fine limestone powder has a lower grinding speed and a larger grinding roller size.
(2) Adjust wind speed control in different parts
After different materials are ground, the particle size is different, the weight of the particles is different, and the concentration of gas-solid two-phase flow is different. To achieve the transportation of particles with a certain particle size, the vertical grinding chamber needs sufficient wind speed for each part, but it is too high. The wind speed will increase the internal friction and affect the energy consumption of the system fan.
Moreover, because there is no external heat source to provide hot air, and the natural wind is passed through the vertical mill, the factors of low ventilation temperature should be fully considered, the key position structure inside the mill should be adjusted to control the wind speed, and the flow field design should be optimized by computer using two-phase flow calculation technology.
(3) Optimize the structure of the classifier
In view of the high fineness of limestone powder, the matching powder separator optimizes the control of particle motion, limits the irregular motion in the vertical roller mill, optimizes the distance between the rotor and the guide vane, the rotor speed, the number of moving and static blades, and the geometric size. Powder screening efficiency.