JPH06102162B2 - Coal-water slurry production equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coal-water slurry manufacturing apparatus, and particularly to a lower ring rotatably installed and an upper ring arranged above the lower ring. The present invention relates to a coal-water slurry producing apparatus suitable for this, which reduces the crushing power of coal in a ring roller mill in which a ball is disposed between the rings and the ball and the coal is compression-milled under wet conditions.

[Conventional technology]

Development of a coal-water slurry is underway to improve the handling of coal, which is a solid fuel. The coal-water slurry is composed of coal, water and a trace amount of a surfactant, and as a manufacturing method thereof, a method of pulverizing coal using a wet mill is generally used.

As a coal-water slurry production apparatus, a wet tube mill has been already proposed, but the present inventors have a feature that the power required for pulverizing coal and the amount of water required to have a predetermined fluidity as a slurry are small. We proposed a coal-water slurry production system using a ring roller mill with a slab (Japanese Patent Application No. 59-
No. 203761 and others). However, since it is difficult to control the residence time of the coal particles in the crushing section in the mill in the coal-water slurry manufacturing apparatus using the ring roller mill, a part of the slurry coming out of the mill is passed through the distributor to the mill. Need to bring back.

FIG. 3 is a system diagram of a conventional coal-water slurry manufacturing apparatus using a ring roller mill. In FIG. 3, the bunker 1
Coal A inside passes through feeder 2 and from coal feed pipe 4 at the top of wet type ring roller mill 3, water B, and surfactant liquid C.
And the pH adjusting agent liquid D are injected into the mill from the tanks 5, 6 and 7 by the respective pumps 8, 9 and 10 through the coal feeding pipe 4. The mixture of coal, water and additives crushed in the ring roller mill 3 is sent from a discharge port 11 at the bottom of the mill to a slurry distributor 13 by a slurry pump 12, part of which is fed from a coal feed pipe 4 of the mill into the mill. Circulated. The remaining slurry distributed by the distributor 13 is sent to the coarse particle separator 14 installed above the mill, and the separated coarse particles are recirculated from the coal feeding pipe 4 of the mill into the mill 3 by gravity. .
The coal-water slurry that has passed through the coarse particle separator 14 is stored in the slurry tank 15 as a product.

FIG. 4 is a sectional view of the ring roller mill in FIG. In FIG. 4, the crushing unit includes a crushing table 17, an upper fixed ring (upper ring) 19 to which a pressing force is applied by a pressure device 18, and a crushing table rotated by a drive device 20.
A lower roller (lower ring) 21 installed at the end of 17 and a plurality of grinding balls 22 arranged between the upper ring 19 and the lower ring 21 and rolling as the lower ring 21 rotates.
And a scraping bar 23 for cleaning the inside of the coal feeding pipe installed eccentrically from the center of the crushing table 17. Coal A to be wet-milled includes circulating slurry from a distributor 13 (see FIG. 3), coarse slurry from a coarse grain separator 14 (see FIG. 3),
Grinder main body together with water, surfactant liquid and pH adjuster liquid
It is supplied to 16 coal feeding pipes 4. The mixture of coal, water and additives supplied to the coal feeding pipe 4 falls inside the coal feeding pipe 4, but the mixture adhering to the inner surface of the coal feeding pipe 4 is scratched by a cleaning scraping bar 23 which rotates together with the grinding table 17. Captured and dispersed on the crushing table 17. The mixture of coal, water and additives dispersed on the crushing table 17 is moved to the crushing ball arrangement portion by the centrifugal force generated by the rotation of the crushing table 17,
Compressed and ground between the ball 22 and the lower ring 21. The crushed coal flows down from the space between the end of the lower ring 21 and the crusher body 16 into the slurry weir 24 under the crushing table 17, while being mixed by the mixing paddle 25 installed at the bottom of the rotating crushing table 17. It is discharged from the discharge port 11.

[Problems to be solved by the invention]

In the above-mentioned coal-water slurry production apparatus, the ratio of the weight of the slurry returned to the ring roller mill 3 to the amount of slurry entering the distributor 13 (hereinafter referred to as the distribution ratio) is 0.90, although it depends on the coal and the grinding conditions. ~ 0.99,
The amount of slurry circulated to the mill is 10 to 100 times the amount of slurry sent to the coarse-grain separator 14. Therefore, there is a problem that the distributor 13 becomes large in size, the size of the circulation pump for circulating the slurry between the distributor 13 and the ring roller mill 3 becomes large, and the pump power increases.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, the residence time of the coal particles in the mill can be controlled without increasing the grinding power, and the distributor, the circulation pump, etc. can be downsized coal-water. It is to provide a slurry manufacturing apparatus.

[Problems to be solved by the invention]

The above-mentioned object is to arrange a ball between a lower ring rotatably installed and an upper ring installed above the lower ring, and to perform compression grinding between the ring and the ball under wet condition of coal. This is accomplished by providing the upper ring in the ring roller mill rotatably in the opposite direction to the lower ring.

[Action]

The coal particles in the slurry are compression ground between the balls and the lower ring. The slurry dropped on the crushing table moves to the lower ring by the centrifugal force accompanying the rotation of the crushing table. The moving speed of the slurry moving to the lower ring side varies depending on the rotation speed of the lower ring, and the residence time in the crushing section can be controlled by this rotation speed. However, if the rotation speed of the lower ring is reduced, the moving speed of the balls also decreases, and the crushing capacity decreases. At this time, when the upper ring is rotated in the direction opposite to the rotating direction of the lower ring, the residence time of the coal particles in the crushing section can be maintained for a predetermined time, and at the same time, reduction of the crushing capacity is prevented.

Example of Invention

Embodiments of the present invention will be described below with reference to the drawings. First
FIG. 1 is a sectional view of a ring roller mill provided in the coal-water slurry manufacturing apparatus according to the present invention, and FIG. 2 is a system diagram of a coal-water slurry manufacturing apparatus having the ring roller mill shown in FIG.

1 and 2 are different from the conventional device shown in FIGS. 3 and 4 in that the upper ring 19 is replaced by the lower ring.
Drive device 26 for rotating in a direction opposite to the rotating direction of 21
Is installed, and a slurry flow meter 28a is installed in the middle of the line for circulating the slurry from the mill 3 to the distributor 3. Coal from the bunker 1, water from the pumps 5, 6 and 7, surfactant liquid and pH. Conditioner liquid, slurry from distributor 13, coarse-grain separator 14
A mixing tank 27 for mixing and storing the slurry from
That is, a slurry flow meter 28b is installed in the middle of a line for introducing the mixed slurry from the mixing tank 27 into the coal feeding pipe 4 of the mill 3. Slurry flow meter 28a and slurry flow meter 2
The detection signal from 8b is input to a controller (not shown), and based on the control signal from this controller, the lower ring
The number of rotations of the drive device 20 that rotates the 21 is controlled. The distributor 13 may be, for example, a branch pipe having a flow rate adjusting valve installed therein, but may be of any type as long as it can distribute coal particles as they are without classifying them. . The coarse particle separator 14 may be of any type, such as a strainer, a wet screen, a sieve bend, etc., as long as it can separate particles of about 300 to 1000 μm or more in the slurry.

In FIG. 1 and FIG. 2, constituent parts other than the above-mentioned constituent parts are the same as those in FIG. 3 and FIG.

Next, the operation of the coal-water slurry manufacturing apparatus configured as described above will be described.

The upper ring 19 is rotated by the drive device 26 in the opposite direction to the lower ring 21. The slurry (mixture of coal, water, surfactant, circulating slurry and coarse-grained slurry) dropped from the coal feeding pipe 4 onto the powder table 17 is moved to the lower ring 21 by the centrifugal force generated by the rotation of the crushing table 17. , Between the balls 22 and the lower ring 21 is compression ground. The slurry containing the crushed coal falls from the space between the end of the lower ring 21 and the crushing body 16 into the slurry weir 24 under the crushing table 17, and mixes by the mixing paddle 25 installed at the bottom of the rotating crushing table 17. While being discharged, it is discharged from the discharge port 11.

During compression grinding of such coal, the lower ring 21
If the number of revolutions of the coal is reduced, the residence time of the coal particles in the crushing section becomes longer, and the degree of crushing when passing once through the crushing section (for example, 20
0 mesh passing amount increase) becomes large. However, if the rotation speed of the lower ring 21 is too low, the slurry is not smoothly discharged to the outside of the mill, the crushing capacity is reduced, and the inside of the mill may be blocked.

In this embodiment, the slurry flow meter 28b measures the flow rate S ₁ of the slurry supplied from the mixing tank 27 to the coal feeding pipe 4 of the mill 3, while the flow rate S ₂ of the slurry discharged from the mill 3 is measured. The slurry flow meter 28a measures the slurry hold-up amount in the mill 3 from the difference between the flow rate S ₁ and the flow rate S _2, and the lower ring 21 of the lower ring 21 is adjusted so that the slurry hold-up amount does not exceed a predetermined value. The rotation speed is controlled.

Next, the effect of the present invention will be shown by a specific operation example.

Operation Example 1 A charcoal (HG150) was manufactured under the following conditions using a mill having a rotary table having a diameter of 165 mm and having a structure as shown in FIG.

(Condition) Coal feed amount to the mill: 20kg / h (dry coal standard) Surfactant amount: 0.5% (relative to coal) Coal concentration in the mill: 72% Upper ring rotation speed: 120rpm Lower ring rotation speed: 60rpm Operation Example 2 A slurry of B charcoal (HG136) was produced in the same manner as in Operation Example 1. However, the amount of coal feed to the mill is 10 kg / h,
The coal concentration in the mill was 68%.

Operation examples 3 and 4 (for comparison) Using the conventional coal-water slurry producing apparatus shown in FIGS. 3 and 4, slurry was produced under the same conditions as in operation examples 1 and 2 for coal A and coal B, respectively. However, the rotation speed of the lower ring at that time was 180 rpm.

Performance results according to Operation Examples 1 to 4 The distribution ratio in the distributor 13 in Operation Examples 1 and 2 is 0.
80 and 0.76. On the other hand, the distribution ratios of Examples 3 and 4 were 0.95 and 0.92, respectively. Comparing this with the amount of slurry supplied to the distributor 13, the operating example 1 is about 140 kg / h, while the operating example 3 is about 560 kg / h, which is about 4 kg in the operating example 1.
Double. Comparing the operation example 2 and the operation example 4, the operation example 4 is tripled. That is, the size of the distributor 13 and the circulation pump 12 is 1/4 to 1/3 and the pump power is also 1/4 to 1/3 by the device of the present invention.

〔The invention's effect〕

As described above, according to the present invention, the residence time of coal particles in the ring roller mill can be controlled, and the pulverization power of coal particles is improved, so that devices such as a distributor and a slurry circulation pump can be downsized, and the pump power is remarkably increased. It can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a ring roller mill provided in a coal-water slurry manufacturing device according to the present invention, FIG. 2 is a system diagram of a coal-water slurry manufacturing device provided with the ring roller mill of FIG. 1, and FIG. System diagram of conventional coal-water slurry production equipment,
FIG. 4 is a cross-sectional view of the ring roller mill in the coal-water slurry manufacturing apparatus of FIG. 1 …… Bunker, 2 …… Feeder, 3 …… Mill, 4 …… Coal supply pipe,
5,6,7 …… Tank, 13 …… Distributor, 14 …… Coarse grain separator, 15…
… Slurry tank, 17 …… Grinding table, 18 …… Pressurizing device, 1
9 …… Upper ring, 20 …… Drive unit, 21 …… Lower ring, 22
…… Ball, 26 …… Drive device.

Claims (2)

[Claims] 1. A ball is arranged between a lower ring rotatably installed and an upper ring installed above the lower ring, and coal is compressed and abraded under wet conditions between the ring and the ball. A coal-water slurry manufacturing apparatus provided with a ring roller mill for crushing, wherein the upper ring is rotatably provided in a direction opposite to a rotating direction of the lower ring. 2. Coal introduced into the ring roller mill
A means for controlling the number of rotations of the lower ring is provided based on the amount of slurry holdup in the ring roller mill calculated from the difference between the flow rate of water slurry and the amount of coal-water slurry discharged from the ring roller mill. The coal-water slurry manufacturing apparatus according to claim (1).