JPS60156797A - Manufacture of highly concentrated coal-water slurry - Google Patents

Abstract

PURPOSE:To attempt to improve in the productivity per unit time of the titled slurry as well as obtaining said high-quality slurry at low cost, by crushing the dehydrated cake prepared by dehydration of a coal-water slurry formed by low- concentration wet process followed by mixing agitation of the resulting crushed cake together with water and additive. CONSTITUTION:First, coal is subjected to wet-pulverization in water using mill 3 to prepare a low-concentration coal-water slurry. Next, said slurry is dehydrated by dehydrator 5 into dehydrated cake, which is then crushed using crusher 8 followed by introduction into mixing agitator 10 to carry out mixing agitation together with water and additive fed through respective pipelines 11 and 12, thus obtaining the objective slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly concentrated coal water slurry with good slurry properties.

High-concentration coal water slurry (hereinafter referred to as high-concentration slurry) is a mixture of 60-90% by weight of finely pulverized coal and 40-10% by weight of water, with some additives added, and can be left as is without dehydration. It is a fluid fuel that can be combusted in boilers, etc., and its range of use can be dramatically expanded by turning solid fuel coal into a fluid.

Conventionally, methods for producing high concentration slurry can be roughly divided into three types: dry method, high concentration wet method, and low concentration wet method.

The dry method uses a mill to pulverize coal in the air, and then mixes and stirs this with water and additives to form a highly concentrated slurry.

In addition, the high concentration wet method uses coal in a tube mill.

Water and additives are added at the same time, and pulverization, mixing, and stirring are performed at the same time.

Furthermore, in the low concentration wet method, coal and water are put into a tube mill and pulverized at a low concentration to form a coal low concentration water slurry, which is then dehydrated in a dehydrator to form a dehydrated cake, which is then transferred to a stirring tank. A small amount of water and additives are again mixed and stirred in the container to form a highly concentrated slurry.The present invention eliminates the drawbacks of the conventional method of making a highly concentrated slurry using this low concentration wet method. .

What is illustrated in FIG. 1 is a flow chart 1 related to a conventional method for producing a high concentration slurry using a low concentration wet method.

In Figure 1, a is the water supply line, b is the coal supply line, C is the mill, and d is the coal content 2 obtained in mill C.
Transport line for 0 to 50% by weight coal low concentration water slurry (hereinafter referred to as low concentration slurry), e is a dehydrator;
This method dehydrates a low concentration slurry to form a dehydrated cake. f is a dehydration circulation line for recirculating the water obtained by dehydration in the dehydrator e to the water supply line a.

Water and coal are supplied to mill C through respective supply lines a and b, and are pulverized at a low concentration to form a low concentration slurry of 20 to 50% by weight. This low concentration slurry is supplied to the dehydrator e through a low concentration slurry transport line d. In the dehydrator e, the low concentration slurry is dehydrated, and the dehydrated water is recirculated to the water supply line a through the dehydration circulation line f, and the dehydrated slurry is sent as a dehydrated cake to the mixing agitator via the dehydrated cake transport line g. supply In this mixer, water and additives supplied from the water supply line i and additive supply line j are mixed and stirred into the supplied dehydrated cake to prepare a high concentration slurry with low viscosity. The concentrated slurry is transported from the concentrated slurry transport line k to a boiler combustion means (not shown) or the like.

In such a conventional low-concentration wet process high-concentration slurry manufacturing method, the dehydrated cake supplied to the mixer 11 via the dehydrated cake transport line g is plate-shaped or in large chunks, so the water is removed by the mixer and stirrer. When preparing a high concentration slurry with low viscosity by mixing and stirring the powder and additives together to form a slurry, it was difficult to atomize the particles. Therefore, in order to obtain uniform mixing, it is necessary to operate the mixer agitator 11 for a long time, resulting in high power costs and poor productivity per unit time to obtain a high-quality, high-concentration slurry.

The present invention solves the drawbacks of the conventional low-concentration wet method for producing high-concentration slurry as described in 1. It aims to produce high-quality high-concentration slurry at a low cost and with a high production output per unit time. It was submitted as a purpose.

That is, in the first aspect of the present invention, 2 coal is wet-pulverized in water to prepare a low-concentration slurry.

Then, a dehydrated cake obtained by dehydrating the low concentration slurry is crushed in a crusher and then introduced into a mixing agitator, and water and additives are supplied to the mixing agitator and mixed and agitated. This is a method for producing a highly concentrated slurry.

Hereinafter, two preferred embodiments of the first aspect of the present invention will be described in detail with reference to the embodiment illustrated in FIG.

The embodiment shown in FIG. 2 is flow chart 1 of the embodiment according to the first invention of the present invention.

In Figure 2, 1 is the water supply line, 2 is the coal supply line, 3 is the mill, and 4 is the coal content 2 obtained in the mill 3.
A transport line 5 for low concentration slurry of 0 to 50% by weight is a dehydrator, and the dehydrator 5 dehydrates the low concentration slurry to form a dehydrated cake. 6 is a dehydration circulation line for recirculating the water obtained by dehydration in the dehydrator 5 to the water supply line 1. 7 is a transportation line for the dehydrated cake, 8 is a crushing device, 9 is a transportation line for the small lump-like dehydrated cake crushed by the crusher 8, 10 is a mixing agitator, 11 and ]2in, 1
3 is a transportation line for high concentration slurry.

In Flow Sea-1, water and coal are supplied to the mill 3 from respective supply lines 1 and 2, and are pulverized at a low concentration to form a low concentration slurry of 20 to 50% by weight.

This low concentration slurry is supplied to a dehydrator 5 via a low concentration slurry transport line 4. The dehydrator 5 dehydrates the low concentration slurry, and the dehydrated water is recirculated to the water supply line 1 through the dehydration circulation line 6.

The dehydrated slurry is supplied as a dehydrated cake to a crushing device 8 via a dehydrated cake transport line 7. This agglomeration device 8 agglomerates the supplied plate-shaped or block-shaped dehydrated cake into small or micro-agglomerates. The dehydrated cake in the form of small lumps or minute lumps (hereinafter abbreviated as small lumps) is supplied to a mixing agitator 10 via a transport line 9 for small dehydrated cakes.

Next, the mixer 10 mixes and stirs the water and additives supplied from the water supply line 11 and the additive supply line 12 to the supplied small block dehydrated cake to form a uniform high concentration slurry with low viscosity. as described in detail based on flow chart 1 of the boiler combustion means (not shown) from the high-concentration slurry transport line 13.

The present invention wet-pulverizes coal in water to prepare a low-concentration slurry, then dehydrates the low-concentration slurry, crushes the resulting dehydrated cake in a crusher, and then introduces it into a mixing agitator. Since water and additives are supplied to a stirrer and mixed and stirred to obtain a highly concentrated slurry, the following effects can be obtained.

1) In order to supply the dehydrated cake to the mixing agitator by crushing it into small pieces, the water and additives for preparing the slurry supplied to the mixing agitator can be mixed and stirred smoothly and with good quality and uniformity. A highly concentrated slurry can be obtained.

2)-! Ta. Since homogeneous mixing can be achieved smoothly, the amount of highly concentrated slurry produced per unit time is significantly increased, and productivity is therefore improved.

Next, the second invention of the present invention is as described below.
This invention was provided in order to solve the problems of the invention and to obtain a higher quality, highly concentrated slurry.

That is, in the production process shown in FIG. 2, two coals are ground in water at a low concentration, so only a small amount of ultrafine coal particles are produced. Therefore, since only a small amount of ultrafine coal particles are contained in the finished high concentration slurry, the rheological properties of the high concentration slurry are dilatant, resulting in poor storage stability. In addition, even if ultrafine coal particles are generated in the mill by some method to make the rheological properties pseudoplastic and improve storage stability, if a large amount of ultrafine coal particles are contained in the low concentration slurry. The dewatering performance of the dehydrator will be significantly reduced, and the moisture content in the dehydrated cake will increase.
There was a drawback that the concentration of the resulting high-concentration slurry was reduced.

The second invention of the present invention improves this low-concentration wet high-concentration slurry production method, and supplies ultra-fine coal slurry obtained by pulverizing a part of the low-concentration slurry with an ultra-fine mill to a mixing and stirring tank. The purpose of this method is to mix and stir the dehydrated cake, water, and additives, and the purpose is to have pseudoplastic rheological properties and excellent storage stability while not reducing the concentration of the finished high-concentration slurry. The purpose of the present invention is to provide a method for producing a highly concentrated slurry in which the grinding capacity is large in a mill of the same size and the power required for grinding is small, which is an advantage of the concentrated wet method.

That is, the second invention of the present invention wet-pulverizes coal in water to prepare a low concentration slurry.

Next, the dehydrated cake obtained by dehydrating the low concentration slurry is crushed in a crusher and introduced into a mixing agitator, and at the same time, a part of the low concentration slurry is crushed in an ultrafine mill to the mixing agitator. This is a method for producing a highly concentrated slurry, which is characterized by supplying an ultrafine coal slurry, water, and an additive, and mixing and stirring the slurry.

Hereinafter, two preferred embodiments of the second invention will be described based on the embodiments shown in FIGS. 3 and 4.

In Fig. 3, 1 is a water supply line, 2 is a coal supply line, 3 is a main mill, 4 is a transportation line for a low concentration slurry with a coal content of 20 to 50% by weight obtained in the main mill 3, and 5
is in a dehydrator.

The dehydrator 5 dehydrates the low concentration slurry to form a dehydrated cake. 6 is a dehydration circulation line for recirculating the water obtained by dehydration in the dehydrator 5 to the water supply line 1;
8 is a transportation line for the dehydrated cake obtained by the dehydrator 5, 8 is a crushing device, 9 is a transportation line for the small lump dehydrated cake crushed by the crusher 8, and 10 is a mixing agitator.

11 and 12 are supply lines for water and additives such as surfactants, which are supplied to prepare a highly concentrated slurry;
13 is a transportation line for high concentration slurry, 14 is a low concentration slurry branch transportation line for branching and transporting the low concentration slurry of low concentration slurry transportation line 4, and 15 is an ultrafine grinding mill, such as a normal tube mill, ball mill, or high-speed shearing mill. Use a force-based grinding mill, etc. 16 is a transport line for ultra-fine coal slurry.

In the embodiment configured in this manner, water and coal are supplied to the main mill 3 from the water supply line 1 and the coal supply line 2 for pulverization.

A low concentration slurry of 20-50% by weight is made. One part of this low concentration slurry is branched and transported from the low concentration slurry transport line 4 to a low concentration slurry branch transport line 14, and the rest is supplied to the dehydrator 5. The dehydrator 5 dehydrates the low concentration slurry.

The dehydrated water is recirculated to the water supply line 1 via the dewatering circulation line 6, and the dewatered slurry is fed as a dehydrated cake to the crushing device 8 via the dehydrated cake transport line 7.

This agglomeration device 8 agglomerates the supplied plate-shaped or block-shaped dehydrated cake into small agglomerates.

This small block dehydrated cake is transferred to the small block dehydrated cake transport line 9.
The mixture is fed to the mixing agitator 10 via the .

On the other hand, a portion of the low concentration slurry branched to the low concentration slurry branch transportation line 14 is supplied to the ultrafine grinding mill 15 . In the ultrafine grinding mill 15, the supplied low concentration slurry is
Grind so that the amount of particles with a particle size of 0μ or less is about 50% by weight or more. In other words, the particle size of ultrafine coal slurry is
The weight ratio of particles of 10μ or less in the highly concentrated slurry is 2.
5% or more.

The ultrafine coal slurry IJ- thus obtained is supplied to the mixing agitator 10 via the ultrafine coal slurry transport line 16. [Mixing Stirrer] 0 mixes and stirs the supplied small lump dehydrated cake and ultrafine coal slurry with the water and additives supplied from the water supply line 11 and the additive supply line 12, to reduce the viscosity. A low-concentration slurry is prepared and transported from the high-concentration slurry transport line 13 to a boiler combustion means (not shown) or the like.

FIG. 4 shows the flow chart-1 of the second embodiment according to the second invention.
・In the first embodiment shown in FIG. 3, the dehydrator 5
A part of the dehydrated water obtained in the above is branched and connected to the water supply line 11 of the first embodiment via a branch pipe 17, thereby reducing the supply of water from outside the system.

As described above in detail based on the flowchart 1 of FIGS. 3 and 4, which are embodiments of the second invention, the second invention of the present invention produces a low-concentration slurry by wet-pulverizing coal in water. Prepare.

Next, the dehydrated cake obtained by dehydrating the gamete concentration slurry was crushed in a lump crusher and then introduced into a mixing agitator, and at the same time, a part of the gamete concentration slurry was crushed in an ultrafine mill. The ultrafine coal slurry obtained by pulverization, water, and additives are supplied and mixed and stirred to obtain a highly concentrated slurry, so in addition to the effects described in the first invention, the following effects can be obtained. It will be done.

1) In the main mill, low concentration (coal 2
Since pulverization is carried out at a concentration of 0 to 50% by weight, it is possible to operate at the point where the pulverizing power is minimal.

2) High dehydration efficiency is possible because dehydration is performed under conditions with few ultrafine coal particles.

3) Addition of ultrafine coal particles makes the rheological properties of the highly concentrated slurry pseudoplastic, improving storage stability.

Furthermore, the third aspect of the present invention is provided to obtain a high-concentration slurry of even better quality.

That is, in the third aspect of the present invention, two coals are wet-pulverized in water to prepare a low concentration slurry.

- A low-concentration slurry obtained by removing coarse particles from the gamete concentration slurry using a classifier (hereinafter referred to as coarse-grain cut low-concentration slurry) and a low-concentration slurry containing coarse particles (hereinafter referred to as coarse-grain-containing low-concentration slurry) The dehydrated cake obtained by dehydrating the coarse grain cut low concentration slurry described above is crushed in a crusher and then introduced into a mixing agitator. This method of producing a highly concentrated slurry is characterized by supplying an ultrafine coal slurry obtained by pulverizing the concentrated slurry in an ultrafine mill, water, and an additive, and mixing and stirring the slurry.

Hereinafter, two preferred embodiments of the third aspect of the present invention will be described based on the embodiments illustrated in FIGS. 5 and 6.

In FIG. 5, ■ is a water supply line, 2 is a coal supply line, 3 is the main mill, and 4 is a transportation line for the low concentration slurry with a coal content of 20 to 50% by weight obtained in the main mill 3.]
, lj: a classifier that separates coarse grains in the supplied low concentration slurry and classifies them into coarse grain cut low concentration slurry and coarse grain containing low concentration slurry, 1QFi classifier 18 classifies coarse grain cut low concentration slurry; The concentration slurry transport line 5 is a dehydrator, and the dehydrator 5 dehydrates the coarse cut low concentration slurry to form a dehydrated cake. 6 is a dehydration circulation line for recirculating the water obtained by dehydration in the dehydrator 5 to the water supply line 1; 20 is a coarse cut dehydrated cake obtained in the dehydrator 5 (hereinafter referred to as coarse cut cake); 8 is an agglomeration device; 21 is a transportation line for small coarsely cut dehydrated cakes crushed by the agglomeration device 8;

10 is a mixing agitator, and 11 and 12 are supply lines for water and additives such as surfactants, which are supplied to prepare a highly concentrated slurry.

22 is a transport line for the coarse particle-containing low concentration slurry classified by the classifier 18, and 15 is a line for transporting coarse coal and pulverized coal in the coarse particle-containing low concentration slurry that has been transported from the coarse particle-containing low concentration slurry transport line. As a mill for ultrafine pulverization, for example, a normal tube mill, ball mill, or grinding type mill using high-speed shearing force is used. 16 is a transport line for the ultrafine coal slurry obtained by the ultrafine grinding mill 15, and 13 is a line for transporting the highly concentrated slurry obtained by mixing and stirring the coarse cut dehydrated cake, water, additives, and the ultrafine coal slurry using the mixing agitator 10. It is a transportation line.

In the embodiment configured in this manner, water and coal are supplied to the main mill 3 from the water supply line 1 and the coal supply line 2 for pulverization.

A low concentration slurry of 20-50% by weight is made. This low concentration slurry is transferred from the low concentration slurry transport line 4 to the classifier 18.
The slurry is divided into coarse grain cut low concentration slurry and coarse grain containing low concentration slurry. The coarse grain cut low concentration slurry is supplied to the dehydrator 5 from a transport line 19.

The dehydrator 5 dehydrates the coarse cut low concentration slurry, and the dehydrated water is recirculated to the water supply line 1 via the dehydration circulation line 6.

Further, the slurry dehydrated by the dehydrator 5 is supplied to the crushing device 8 as a coarse cut dehydrated cake via a coarse cut dehydrated cake transport line 20.

This agglomeration device 8 agglomerates the supplied plate-shaped or lump-like coarse cut dehydrated cake into small agglomerates. The coarse cut small block dehydrated cake is supplied to the mixer 10 via the coarse cut I/small block dehydrated cake transport line 21.

On the other hand, the coarse grain-containing low concentration slurry obtained by classification by the five classifier 18 is supplied to the ultrafine grinding mill 15 from the transport line 22. The ultra-fine grinding mill 15 grinds the coarse coal and pulverized coal in the supplied coarse grain-containing low concentration slurry so that the amount of coal under 10 μm is approximately 50% by weight or more. That is, the particle size of the ultrafine charcoal slurry is set to a particle size necessary to make the weight ratio of particles of 10 μm or less in the finished high-concentration slurry to 25% or more.

The ultrafine coal slurry thus obtained is supplied to the mixing agitator 10 via the transport line 16. The mixer 10 mixes and stirs the supplied dehydrated cake in the form of coarse cut small blocks and the ultrafine pulverized coal slurry with the water and additives supplied from the water supply line 11 and the additive supply line 12. A high-concentration slurry with low viscosity is prepared and transported from a high-concentration slurry transport line 13 to a boiler combustion means (not shown) or the like.

FIG. 6 shows the flow sheet I of the second embodiment according to the third invention.
・In the first embodiment shown in FIG. 5, the dehydrator 5
A part of the dehydrated water obtained in the above is branched and connected to the water supply line 11 of the first embodiment via a branch pipe 17, thereby reducing the supply of water from outside the system.

Figures 5 and 6 which are embodiments of the third invention
As described in detail based on flow chart 1 of the figure, the third invention of the present invention wet-pulverizes coal in water to prepare a low-concentration slurry.

Next, the above-mentioned low concentration water slurry is classified into coarse cut low concentration slurry and coarse particle containing low concentration slurry using a classifier, and the coarse cut dehydrated cake obtained by dehydrating the above coarse cut low concentration slurry is crushed. After being crushed in a device, it is introduced into a mixer and agitator, and at the same time, the ultrafine pulverized coal slurry obtained by pulverizing the coarse grain-containing low concentration slurry described in "2" in an ultrafine mill, as well as water and additives, are supplied to the mixer and agitator. Since a highly concentrated slurry is obtained by mixing and stirring, the following effects can be obtained in addition to the effects described in the first and second inventions.

1) Take out the coarse grains with a classifier, and crush the coarse grains and fine grains contained in the low concentration slurry containing the coarse grains with an ultra-fine grinding mill until they become ultra-fine coal particles. Since the slurry is supplied to a concentrated slurry to produce a highly concentrated slurry, the highly concentrated slurry does not contain coarse particles. Therefore, when the high-concentration slurry obtained by the present invention is combusted in a boiler or the like, the unburned carbon content is reduced, and the combustion efficiency can be significantly increased compared to conventional high-concentration slurries.

[Brief explanation of the drawing]

FIG. 1 shows flow chart 1 of a conventional high concentration slurry production method using a low concentration wet method, and FIGS. 2 to 6 show flow chart 1 of an embodiment of the present invention. 1...Water supply line, 2...Coal supply line, 3.
・・Main mill, 4・Low concentration slurry transport line, 5・
... Dehydrator, 6. Dehydration circulation line, 7. Dehydration cake transport line. 8... Clumping device, 9... Small lump dehydrated cake transport line, 10... Mixing agitator. 11...Water supply line, 12...Additive supply line, 13...High concentration slurry transport line, 14...Low concentration slurry branch transport line, 15---Ultra fine grinding mill, 16°1 Ultra-fine coal slurry transportation line, 17...
Branch pipe, 18... Classifier,] 9... Coarse cut low concentration slurry transport line, 20... Coarse cut dehydrated cake transport line, 21... Coarse cut small block dehydrated cake transport line . 22...Low concentration sura IJ containing coarse grains- Calyx 1 figure $2 figure 3 Calyx

Claims (1)

[Claims] 1) Coal is wet-pulverized in water to prepare a low-concentration coal water slurry, and then the dehydrated cake obtained by dehydrating the above-mentioned low-concentration coal water slurry is crushed in a crushing device and then mixed. A method for producing a high-concentration coal water slurry, which comprises introducing the slurry into a stirrer, and supplying water and additives to the mixing agitator for mixing and stirring. 2) Wet-pulverize coal in water to prepare a low-concentration coal water slurry, then dehydrate the above-mentioned low-concentration coal water slurry, and crush the obtained dehydrated cake with a crusher, and then introduce it into a mixing agitator, A superfine coal slurry obtained by pulverizing a part of the low-concentration coal water slurry in an ultrafine mill, water, and additives are supplied to the mixing agitator and mixed and agitated. A method for producing highly concentrated water slurry. 3) Wet-pulverize coal in water to prepare a low-concentration coal water slurry, and then use a classifier to remove coarse particles from the low-concentration coal water slurry described in -1-, which contains the low-concentration coal water slurry and coarse particles. The dehydrated cake obtained by dehydrating the coal low concentration water slurry from which the coarse particles have been removed is crushed by a crushing device, and then introduced into a mixing agitator, and the mixture is mixed. A highly concentrated coal characterized by supplying an ultrafine coal slurry obtained by pulverizing a low concentration coal water slurry containing coarse particles in an ultrafine mill, water, and additives to a stirrer and mixing and stirring them. Method for producing water slurry.