JPH0645015B2 - Method for adjusting particle size distribution of high-concentration coal water slurry - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for adjusting the particle size distribution of highly concentrated coal water slurry.

[Problems to be solved by conventional technology and invention] In the present situation in Japan, it is difficult to use a certain brand of coal for a long period of time, and many types of overseas coal and domestic coal are used. . Coal properties will differ not only when the brand changes but also when the same brand has different collection locations. When the coal properties are changed as described above, the following problems occur when the coal is crushed under the same conditions.

(1) Coal that is easily pulverized has a too fine particle size distribution and increases the specific surface area of the particles, which requires many additives and is uneconomical.

(2) On the contrary, for coal that is difficult to be crushed, the particle size distribution becomes coarse and the stability of the high-concentration coal water slurry becomes poor. In some cases, the water slurry must be disposed of.

It is considered that these drawbacks are due to the fact that the conventional methods did not constantly monitor the particle size distribution of the product high concentration coal water slurry and did not have the function of adjusting the particle size distribution.

[Means for Solving the Problems] In order to solve the above problems, the present invention uses a plurality of ultra-fine grinding mills driven according to the output of a particle size distribution monitor, and the particle size distribution of coal to be processed. Is constantly measured by the monitor, and when the particle size distribution is coarser than the predetermined one, the number of operating units of the ultrafine grinding mill is increased according to the output signal of the monitor, and when the particle size distribution is fine, the ultrafine particle This is a method for adjusting the particle size distribution of a high-concentration coal water slurry, in which the number of operating mills is reduced according to the output signal of the monitor.

[Operation] The particle size distribution adjusting method for a high-concentration coal water slurry according to the present invention links the particle size distribution monitor for coal and the ultrafine grinding mill to determine the number of operating ultrafine grinding mills according to the particle size distribution of coal. By adjusting the addition ratio of the ultrafine particle slurry to the product high concentration slurry, and also adjusting the particle size distribution of the ultrafine particle slurry, adjusting the ultrafine particle content rate, the particle size distribution of the product high concentration slurry Is always constant.

Thus, the method of the present invention can be applied to the apparatus for producing a high-concentration coal water slurry as shown in FIGS. 3 to 6. The apparatus for producing high-concentration coal water slurry shown in FIG. 3 supplies the coal in the storage tank 1 to the coarse crushing mill 6 through the lines 2 and 4 to supply the coarse crushing mill feed water from the tank 3 to the crushing process at a low concentration. It is designed to make a low concentration slurry of 20 to 60% by weight of the coal. This low-concentration slurry is sent to a classifier 8 through a line 7 and separated into a coarse-particle-cut low-concentration slurry and a coarse-particle-containing low-concentration slurry, and the coarse-particle-containing low-concentration slurry is returned to a mill 6 by a line 10 for re-grinding. It is like this. The coarse-grain-cut low-concentration slurry is sent to the dehydrator 11 through the line 9 and dehydrated.
From the dehydration water distributor 13 to the reuse line 14, 1
It is sent to 5, 16 for reuse. On the other hand, the dehydrated cake is sent to the slurry adjustment tank 26 via the line 25.
And the product is prepared by stirring with the adjusted water sent from the adjusted water tank 18 through the line 22 and the additive sent from the additive tank 20 through the line 24 to adjust the water concentration. It is designed to make highly concentrated slurries. This product high-concentration slurry is distributed via line 27 to a slurry for ultrafine grinding mill and storage slurry by a distributor 28, and the storage slurry is sent to a product high-concentration slurry storage tank 33 via line 29. It is designed to be stored. Further, the slurry for the ultra-fine crushing mill is sent to the fine crushing mill 31 through the line 30 to be subjected to the ultra-fine crushing, and the obtained ultra-fine crushing slurry is added to the tank 26 through the line 32. . At the inlet of the mill 31, adjusted water is supplied from the adjusted water tank 17 via the line 21 and the additive sent from the additive tank 19 via the line 23 to adjust the water concentration. It is like this. In this way, by adding an appropriate amount of the ultrafine particle slurry obtained by the ultrafine crushing mill 31, it is possible to obtain a good product high-concentration slurry adjusted to a predetermined particle size distribution.

The high-concentration coal water slurry manufacturing apparatus shown in FIG.
The outlet slurry of the coarse crushing mill 6 is used as the inlet slurry of the ultrafine crushing mill 31 via the line 7a. The high-concentration coal water slurry manufacturing apparatus shown in FIG.
The coarse-grain-cut side slurry is passed through the distributor 34 to the line 9a.
It is then sent to the ultra-fine crushing mill 31. The apparatus for producing high-concentration coal water slurry shown in FIG. 6 converts coal before crushing into slurry in a mixing vessel 35 and sends it to the ultrafine crushing mill 31 through a line 36. It should be noted that all of the high-concentration coal water slurry production apparatuses shown in FIGS. 4 to 6 differ from the high-concentration coal water slurry production apparatus shown in FIG. 3 only in the inlet slurry of the ultrafine grinding mill 31. The other configurations are the same as those of the high-concentration coal water slurry manufacturing apparatus shown in FIG.

EFFECTS OF THE INVENTION According to the method for adjusting the particle size distribution of high-concentration coal water slurry according to the present invention, the particle size distribution is quickly measured in the transportation line of the product high-concentration slurry, and the addition amount of the ultrafine particle slurry is adjusted. Since it does so, it has the following effects.

(1) The amount of so-called malicious product high-concentration slurry having a coarse particle size distribution can be significantly reduced.

(2) The amount of uneconomical product high-concentration slurry that requires a large amount of so-called additives with a fine particle size distribution can be significantly reduced.

As a result, it is possible to constantly produce an economical product high-concentration slurry having a uniform particle size distribution even when the coal properties change.

[Examples] FIG. 1 is an explanatory view showing a configuration of a main part of a device for producing a high-concentration coal water slurry that applies the method of the present invention. A small amount of the product high-concentration coal water slurry is collected through the sampling line 41 in the middle of the line 29 (may be in the middle of the line 27), and the particle size distribution measuring device 40 measures the particle size distribution of the coal particles. . This particle size distribution measurement time is, for example, 3 to 5 when a laser particle size distribution measuring instrument is used.
Minutes. In this embodiment, when three ultrafine grinding mills are installed, usually two mills 31a and 31b are operated, and when the above-mentioned particle size distribution measurement result is coarser than the set particle size distribution, the line 43 is used. A signal is sent to the flowmeter 41 so as to increase the flow rate through the line 30, and the distributors 28a and 2
The slurry flow rate is increased to a predetermined flow rate by 8b, and at the same time, the opening / closing valves 37c and 38c are opened and the mill 31c is also started to operate.

As a result, the amount of the ultrafine powder slurry sent to the tank 26 through the line 32 increases, and the coarse particle size distribution of the product high-concentration slurry is restored to the predetermined particle size distribution. When the particle size distribution is smaller than the set particle size distribution, the opposite effect occurs. At the same time as the flow rate is reduced, the on-off valves 37b and 38b are closed and the mill 31b is stopped, and only one mill 31a is operated, and the product high-concentration slurry is too fine. The particle size distribution is restored to a predetermined particle size distribution.

FIG. 2 shows another embodiment in which ultrafine grinding mills are arranged in series, and the operation is exactly the same as that of the embodiment shown in FIG.

The method of adjusting the particle size distribution of the product high-concentration slurry by adjusting the addition rate of the ultrafine-grained slurry, that is, the amount of slurry supplied to the ultrafine-mill, was described. The goal can be achieved even if the value is constant. That is, when the particle size distribution of the product high-concentration slurry becomes coarse,
The amount of slurry supplied to the line 30 is constant and the mills 31a, 31
If all three b, 31c, and 3 units are operated, the grinding time in each mill will increase, and as a result, the ultrafine particles slurry supplied from the line 32 can be made into ultrafine particles, and the particle size distribution of the product high-concentration slurry will be increased. Can be restored to a predetermined particle size distribution. When the particle size distribution of the product high-concentration slurry is fine, conversely, the number of operating ultrafine grinding mills should be reduced.

[Brief description of drawings]

FIG. 1 and FIG. 2 are explanatory views showing the configuration of the main part of a high-concentration coal water slurry production apparatus to which the method of the present invention is applied, and FIGS. It is explanatory drawing which shows schematic structure of the manufacturing apparatus of a coal water slurry. 1, 1a ... Coal supply reservoir, 2, 2a ... Coal supply line, 3 ... Coarse crushing mill supply water tank, 4 ... Coarse crushing mill supply water supply line, 5 ... Replenishment water supply line, 6 ... Coarse Grinding mill, 7 ... Low-concentration slurry transportation line, 8 ... Classifier,
9 ... Transport line for coarse-grain-cut low-concentration slurry 10 ... Return circulation line for coarse-grain-containing low-concentration slurry, 11 ... Dehydrator, 12
… Dehydration water drain line, 13… Dehydration water distributor, 14,
15, 16, 16a ... Dehydration water reuse line, 17, 1
8, 18a ... Adjusted water tank, 19, 20 ... Additive tank 21, 21, 22a ... Adjusted water supply line, 2
3, 24 ... Additive supply line, 25 ... Coarse grain cut dehydrated cake transportation line, 26 ... Slurry adjusting tank, 27 ... Product high-concentration slurry discharge line, 28 ... Product high-concentration slurry distributor, 29 ... Product high-concentration slurry Transportation line, 30 ... Supply line of ultra-fine grinding mill for product high-concentration slurry, 31 ... Agitation-type ultra-fine grinding mill, 32 ... Ultra-fine grain slurry transportation line, 33
... Product high-concentration slurry storage tank, 7a ... Supply line of low-concentration slurry to ultrafine grinding mill, 9a ... Supply line of coarse-grain cutting low-concentration slurry to ultrafine-milling machine, 34 ... Coarse-grain cutting low-concentration slurry Distributor, 35 ... Mixing tank of coal and water before crushing, 36 ... Supply line to slurry ultrafine crushing mill of coal and water before crushing, 28a, 28b ... Distributor, 30a, 39
b, 30c ... Supply line of product high-concentration slurry to ultrafine grinding mill, 31a, 31b, 31c ... Ultrafine grinding mill, 39
... Transportation pump for product high-concentration slurry, 40 ... Particle size distribution measuring device, 41 ... Flowmeter, 37a, 37b, 37c, 38a,
38b, 38c ... On-off valve, 42 ... Slurry sampling line, 43, 44, 45, 46 ... Signal line, 47,
47a, 47b, 47c ... Ultra fine grain sly transportation line.

Claims (1)

[Claims] 1. When a plurality of ultra-fine grinding mills driven according to the output of a particle size distribution monitor are used and the particle size distribution of coal to be treated is constantly measured by the monitor, and the particle size distribution is coarser than a predetermined particle size distribution. To increase the operating number of the ultra-fine grinding mill according to the output signal of the monitor, and when the particle size distribution is fine, decrease the operating number of the ultra-fine grinding mill according to the output signal of the monitor. A method for adjusting the particle size distribution of a high-concentration coal water slurry, which comprises: