JPH04244247A - Operation of roller mill - Google Patents

Abstract

PURPOSE:To perform safe operation by reducing vibration even when the supply amount of an object to be ground is little and to enhance the response of the amount of a product at the time of a sudden change in the supply amount. CONSTITUTION:The object 2 to be ground supplied to a table 9 is dried by the hot air blown up around the table 9 rotating around a drive shaft and finely ground by the table 9 and a plurality of the rollers 10 rotating while pressing the upper surface of the table 9 and, if the supply amount of the object 2 to be ground is little when the finely ground object 2 is guided to the outside of a roller mill from the outlet provided to the upper part of the roller mill by hot air, outlet temp. 8 is lowered and the moisture of the object 2 to be ground on the table 9 is increased to lower the grinding properties of the object 2 to be ground and the layer of the object 2 to be ground between the rollers 10 and the table 9 is made thick not only to reduce vibration but also to increase the holding amount in the mill. When the supply amount of the object to be ground is much, the outlet temp. is made high and the grinding properties of the object to be ground is improved to reduce the holding amount in the mill and the change of the holding amounts in the mill at the times when the supply amount is little and much is reduced to enhance the response of product quantity to the change of the supply amount.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller mill that is applied to roller mills for crushing coal in pulverized coal-fired boilers, clinker in the cement industry, roller mills for crushing blast furnace slag, and the like.

0002

[Prior Art] In conventional roller mills, the outlet temperature of the roller mill is not changed depending on the amount of material to be crushed.
It is simply controlled to a constant value (usually about 80° C.) (see the solid line in FIG. 6).

0003

Conventionally, as described above, the outlet temperature of the roller mill was kept at a constant value, but the following problem occurred. That is, (1) As shown by the solid line in Figures 4 and 5, when the supply amount of the material to be crushed decreases, the layer of material to be crushed between the roller and the table becomes thinner, the cushioning effect becomes smaller, and the mill Vibrations will increase, making safe driving impossible. (2) When changing the amount of the product (finely pulverized material to be ground), there is a problem that even if the amount of material to be ground is changed, the amount held in the mill changes greatly, resulting in a large response delay time. Ta.

The present invention has been proposed in view of the above-mentioned problems, and its purpose is to reduce vibration and enable safe operation even when the amount of material to be crushed is small. Another object of the present invention is to provide a method of operating a roller mill that can improve the responsiveness of the product amount when the supply amount suddenly changes.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the method of operating a roller mill of the present invention is such that hot air is supplied onto the table rotating around a drive shaft by hot air blown up around the table. While drying the material to be crushed,
The table and a plurality of rollers that rotate while pressing the top surface of the table crush and pulverize the material on the table, and the pulverized material is transferred to the outlet above the roller mill by the hot air. It is characterized in that the temperature at the outlet is changed in accordance with the amount of supplied material to be crushed when the material is guided from the roller mill to the outside of the roller mill.

[0006]

[Operation] As described above, the method of operating the roller mill of the present invention is to dry the material to be crushed that is supplied onto the table by the hot air blown up around the table that rotates around the drive shaft, and to The material to be crushed on the table is crushed and pulverized by multiple rollers that rotate while pressing the top surface of the table, and the pulverized material is guided out of the roller mill from the outlet above the roller mill by hot air. When the supply amount is small, the outlet temperature is lowered,
Increase the moisture content of the material to be crushed on the table, making it harder to grind, and thickening the layer of material between the rollers and the table to reduce vibration and increase the amount of coal held in the mill. . ■If the supply amount is large, the outlet temperature will be raised to improve the pulverization of the material to be crushed, and the amount of coal held in the Miku will be reduced, reducing the change in the amount of coal held when the supply amount is low and high. This improves the responsiveness of product volume to changes in supply volume.

[0007]

[Example] Next, the method of operating the roller mill of the present invention will be explained using an embodiment shown in FIG. , 6 is a flow meter, and 7 is an inlet temperature. FIG. 2 is an explanatory diagram showing a mill outlet temperature program, and FIG. 3 is an explanatory diagram showing an outline of the roller mill 1. In FIG. 3, 8 is the outlet temperature, 9 is the table, 10 is the roller, and 11 is the hot air.

[0008] Also, it is an explanatory diagram showing the relationship between the supply amount and the amount held in the Miku (layer of material to be crushed on the table). Material to be crushed 2
In particular, for materials to be crushed 2 that contain moisture, such as coal (about 10% total moisture), the crushability changes depending on the moisture content. If there is too much, the crushability will be poor. On the other hand, when the outlet temperature 8 of the roller mill 1 changes, the drying performance of the material 2 to be dried in the mill also changes, and as the outlet temperature 8 becomes lower, the moisture content of the material 2 to be crushed increases. Therefore, (1) when the supply amount is small, lower the outlet temperature 8,
The water content of the object 2 to be crushed on the table 9 is increased to worsen the crushability. As a result, the two layers of the material to be crushed between the rollers 10 and the table 9 become thicker, vibrations are reduced, and the amount of coal retained in the mill increases. (2) When the supply amount is large, the outlet temperature 8 is increased to improve the crushability of the material to be crushed 2 and to reduce the amount of coal held in the mixer. As a result, the change in the amount of coal held between when the supply amount is low and when it is high is reduced, and the responsiveness of the product amount to changes in the supply amount is improved.

The object 2 to be crushed is transferred to the roller mill 1
The relationship between the supply amount and the outlet temperature is set, for example, as shown by the broken line in FIG. Then, as shown in FIG. 1, the amount of the material to be crushed 2 supplied to the roller mill 1 is measured, and based on the measurement results, the opening degrees of the hot air damper 4 and the cold air damper 5 are controlled to Temperature 8 is maintained at a predetermined value. If the outlet temperature 8 itself is used as the control input for the opening degree of the dampers 4 and 5 at this time, when the supply amount of the material to be crushed 2 suddenly changes,
Because the heat capacity of the roller mill 1 body is large, the outlet temperature is 8.
response is slow and fluctuations are large. Therefore, the inlet temperature 7 corresponding to the outlet temperature 8 is predicted and controlled by the inlet temperature 7.

0010

Effects of the Invention As described above, the method of operating the roller mill of the present invention uses the hot air blown up around the table that rotates around the drive shaft to dry the material to be crushed that is supplied onto the table. The material to be crushed on the same table is crushed and pulverized by a plurality of rollers that rotate while pressing the top surface of the table, and the pulverized material is transferred to the roller mill from the outlet above the roller mill by the hot air. When introducing the material to the outside, the temperature at the outlet is changed depending on the amount of the material to be crushed. In other words, ■ When the supply amount is small, the outlet temperature is lowered, the moisture content of the material on the table increases, and the grindability becomes worse, thereby thickening the layer of the material between the rollers and the table. . Therefore,
Vibration can be reduced (see Figure 5), and
The amount of coal held in the mill can be increased. ■When the supply amount is large, the outlet temperature is increased to improve the crushability of the material to be crushed and reduce the amount of coal held in the mixer. Therefore, the change in the amount of coal held between when the supply amount is low and when it is high can be reduced (see FIG. 4), and the responsiveness of the product amount to changes in the supply amount can be improved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of the configuration of an apparatus used to carry out the method of operating a roller mill of the present invention.

FIG. 2 is an explanatory diagram showing a mill outlet temperature program.

FIG. 3 is a longitudinal side view schematically showing a roller mill.

FIG. 4 is an explanatory diagram showing the relationship between the supply amount and the amount held in Miku (layer of material to be crushed on the table).

FIG. 5 is an explanatory diagram showing the relationship between supply amount and mill vibration.

FIG. 6 is an explanatory diagram showing mill outlet temperature.

[Explanation of symbols]

1 Roller mill 2 Object to be crushed 3. Product 4 Hot air damper 5 Cold air damper 6 Flow meter 7 Inlet temperature 8 Outlet temperature 9 Table 10 Roller 11 Hot air

Claims (1)

[Claims] Claim 1: A plurality of rotary plates that rotate while pressing the table and the top surface of the table, which dry the material to be crushed that is supplied onto the table by hot air blowing up around the table that rotates around the drive shaft. The material to be ground on the same table is pulverized and pulverized by the rollers, and when the pulverized material is guided to the outside of the roller mill from the outlet above the roller mill by the hot air, the temperature at the outlet is increased. A method of operating a roller mill characterized by changing the amount of supplied pulverized material.