JPH0576991B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing highly concentrated coal-water slurry, and particularly to a method for improving the properties of the slurry by employing a deashing system. It is something.

[Conventional technology]

High concentration coal water slurry is finely ground coal 60~
It is a mixture of 90% by weight and 10-40% by weight of water with some additives, and is a fluid fuel that can be burned as is in a boiler etc. without dehydration, and it converts coal, which is a solid fuel, into a fluid. This dramatically expands the scope of use. In addition, the coal water slurry will be simply abbreviated as slurry below.

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.

In the dry method, coal is pulverized in air using a mill, and then mixed and stirred (hereinafter referred to as mixing and stirring) with water and additives to form a highly concentrated slurry.

Further, in the high concentration wet method, coal, water and additives are simultaneously charged into a tube mill, and pulverization and mixing and stirring are performed at the same time.

Furthermore, coal and water are put into a low concentration wet process tube mill and finely pulverized at a low concentration.
After forming a low-concentration slurry of ~60% by weight and 40-80% by weight of water, this is dehydrated in a dehydrator to form a dehydrated cake, which is then mixed and stirred again with a small amount of adjusted water and additives in the mixer. to make a high concentration slurry.

What is illustrated in FIG. 11 is a flow sheet relating to a conventional method for producing a low-concentration wet high-concentration slurry.

In FIG. 11, a is a storage tank for supplying coal;
b is a coal supply line, c is a tank for milk supply water, d is a supply line for mill supply water, e is a wet mill, f is a transport line for the low concentration slurry obtained in wet mill e, and g is a dehydrator. , h is the discharge line of the dehydrated water obtained by dehydrating with dehydrator g, and i is the slurry obtained by dehydrating with dehydrator g (hereinafter referred to as dehydrated cake).
j is a mixing agitator, k is a tank for conditioning water that supplies conditioning water to the mixing agitator j via a conditioning water supply line l, m is a line n that supplies additives to the mixing agitator j. a tank for additives supplied through the tank, o is a transport line for the highly concentrated slurry that is the product,
p is a combustion means (hereinafter referred to as a product slurry tank) such as a storage tank or a boiler for the highly concentrated slurry that is the product.

In such a flow sheet, the storage tank a
Coal and mill supply water are supplied from tank c to wet mill e through lines b and d, and coarsely pulverized at a low concentration to produce a low concentration slurry. This low concentration slurry is supplied to the dehydrator g via line f. In the dehydrator g, the low concentration slurry is dehydrated, the dehydrated water is drained from the line h, and the dehydrated cake is supplied to the mixer j through the line i. This mixer j mixes and stirs the supplied dehydrated cake with the conditioning water and additives supplied from tanks k and m via lines l and n to form a highly concentrated slurry with low viscosity. The slurry is supplied from the high concentration slurry line o to the product slurry tank p.

[Problem that the invention seeks to solve]

In such a conventional low-concentration wet method for producing high-concentration slurry, a line o is
The highly concentrated slurry that comes out as a product is prepared by coarsely pulverizing and dehydrating coal in a wet mill and then supplying conditioning water and additives, which causes the following problems. Ta.

(b) Since the additives were still being mixed and stirred, the additives were not evenly dispersed in the product slurry, and the quality of the product slurry was uneven.

(b) The highly concentrated slurry that comes out as a product from the mixer j through the line o is obtained by only coarsely pulverizing the coal in the wet mill e, so the shape of the coal particles is angular. When mixed with the additive and stirred, the additive was not well dispersed. For this reason, the effects of the additives could not be fully exhibited, and a highly concentrated slurry with low viscosity could not be obtained.

(c) High concentration slurry contains minute free ash (hereinafter referred to as ash) generated during crushing, so the calorific value per unit weight of slurry is small.

In addition, the ash content caused clogging in the burner during combustion in the boiler, which sometimes hindered the stable supply of high-concentration slurry. Furthermore, a large amount of ash is generated after combustion due to the ash content, and in particular, in combustion in a boiler, ash processing equipment has become large in order to process the large amount of ash content, and a large amount of work is required for processing.

As described above, in the conventional low-concentration wet method for producing high-concentration slurry, there is a problem in that the high-concentration slurry that comes out as a product from mixer j through line o has variations, that is, uniformity in quality. As a result, when used in a boiler or the like, there was a possibility that the combustion state would be inconsistent.

The present invention solves the problems of the conventional low-concentration wet high-concentration slurry manufacturing method described above, and removes the ash contained in coal before combustion to produce a fuel with a large calorific value per unit weight of slurry. The purpose of this product is to eliminate the need to dispose of a large amount of ash, which was caused by combustion in a boiler, and to eliminate problems caused by ash adhesion, and to obtain a high-quality, highly concentrated slurry with low viscosity and uniformity. be.

[Means for solving problems]

The first aspect of the present invention is to coarsely pulverize coal in water to create a low-concentration coal slurry, then deash and dehydrate the low-concentration slurry, and introduce the resulting deashed and dehydrated cake to a mixer and stirrer. The adjusted water, additives, and demineralized dehydrated cake supplied by the mixing agitator are mixed and stirred with the returned adjusted demineralized slurry to produce a kneaded high-concentration demineralized slurry, and then the kneaded high-concentration demineralized slurry is further mixed with the above-mentioned kneaded high-concentration demineralized slurry. is introduced into a dispersion machine, and the above-mentioned additive is uniformly dispersed in the above-mentioned kneaded high-concentration demineralized slurry by the same dispersion machine, and the obtained dispersed high-concentration demineralized slurry is further adjusted in a slurry adjustment tank and supplied as a product. and a method for producing a high concentration slurry, characterized in that a part of the adjusted high concentration demineralized slurry is returned and circulated as it is to the mixing agitator.

[Effect]

Coal and water are supplied to a coarse grinding mill for coarse grinding to produce a low concentration slurry with a high moisture content. This low-concentration slurry contains a lot of ash and moisture generated during coarse grinding, which will have a negative impact on the combustion efficiency in boilers, etc., and in order to equalize the moisture concentration of the slurry obtained with a mixing agitator, it is deashed. Dehydrate later. The deashed and dehydrated cake obtained by deashing and dehydrating is introduced into a mixing agitator. The mixing agitator has
Adjusted water for adjusting the water concentration of the slurry, additives, and the above-described decalcified dehydrated cake are mixed and stirred together with the returned adjusted decalcified slurry to obtain a highly concentrated decalcified slurry.

This kneaded high-concentration demineralized slurry is fed into a dispersing machine and subjected to high-speed shearing to uniformly disperse the additives in the kneaded high-concentration demineralized slurry. Next, this dispersed high-concentration demineralized slurry is sent to a slurry conditioning tank and adjusted to obtain a high-quality adjusted high-concentration demineralized slurry with low viscosity and uniformity. While this adjusted high concentration demineralized slurry is supplied as a product, a portion of it is returned as is to the mixing agitator and then returned to the agitator again to produce a high quality product with less ash content and more uniformity.

〔Example〕

A preferred embodiment of the first aspect of the present invention will be described in detail in the embodiment illustrated in FIG.

The embodiment illustrated in FIG. 1 is a flow sheet of the embodiment according to the first invention.

In Figure 1, 1 is a coal supply storage tank, 2 is a coal supply line, 3 is a tank for coarse grinding wet mill supply water, and 4 is coarse grinding wet mill supply water (hereinafter referred to as coarse grinding mill supply water). 5 is a coarse grinding wet mill (hereinafter referred to as coarse grinding mill); 6 is a transport line for the low concentration slurry obtained in the coarse grinding mill 5;
8 is a deashing device that performs a deashing operation by flotation separation with microbubbles mixed in, 8 is a discharge line for the ash obtained in the deashing device 7, and 9 is a low concentration deashing slurry obtained in the deashing device 7. transportation line, 10 is a dehydrator, 1
1 is a discharge line for dehydrated water obtained from the dehydrator 10;
12 is a transport line for the deashed and dehydrated cake obtained by the dehydrator 10, 13 is a mixer and agitator, and 14 is water supplied to adjust the moisture concentration of the deashed slurry in the mixer and agitator 13 (hereinafter referred to as adjustment water). 15 is a supply line for the regulated water, 16 is a tank for storing additives such as surfactants (hereinafter referred to as additives) to be supplied to the mixing agitator 13 (hereinafter referred to as additive tank). ), 17 is an additive supply line,
18 is a transportation line for the kneaded high-concentration demineralized slurry mixed and kneaded by the mixer 13, 19 is a dispersion machine such as a line mixer, and 20 is a dispersion machine 19 where the slurry in the machine is subjected to high-speed shearing. A transportation line for the dispersed high concentration demineralized slurry obtained by uniformly dispersing, 21 a slurry adjustment tank, 22 a transportation line for the adjusted high concentration demineralization slurry whose concentration is further made uniform in the slurry adjustment tank 21, 23 is a mixer 13 in which a part of the adjusted high concentration demineralized slurry is directly mixed.
24 is a transportation line for high-quality high-concentration demineralized slurry (hereinafter referred to as product high-concentration demineralized slurry) to be supplied as a product or to the next process, 25 is a return circulation line for returning it as a product or to the next process This tank stores the product high concentration demineralized slurry to be supplied (hereinafter referred to as the tank for product high concentration demineralized slurry). Note that the line 24 may be directly connected to a combustion means such as a boiler (not shown), but a description of this will be omitted since it is the same below. Note that necessary transport pumps and the like are omitted in this flow sheet.

In such an embodiment illustrated in FIG.
The coal in the coal storage tank 1 and the coarse grinding mill feed water in the feed water tank 3 are supplied to the coarse grinding mill 5 via lines 2 and 4, and coarsely ground at a low concentration to produce a low concentration of coal of 20 to 60% by weight. Make slurry. This low concentration slurry is supplied to a deashing device 7 through a line 6, and the ash obtained by deashing is discharged through a line 8, while the low concentration deashing slurry is supplied to a dehydrator 10 through a line 9. . The dehydrated water produced by dehydration in the dehydrator 10 is discharged from a line 11, while the deashed and dehydrated cake is supplied to a mixing agitator 13 via a line 12. In the mixing agitator 13, a tank 14 for adjusting water is used to adjust the water concentration of the deashed and dehydrated cake and slurry.
While mixing and stirring together the adjusted water supplied from the additive tank 16 through the line 15, the additives supplied from the additive tank 16 through the line 17, and the returned adjusted demineralized slurry returned from the return circulation line 23. Adjust the concentration so that it is appropriate.
The kneaded high-concentration demineralized slurry obtained by mixing and agitating with the mixer 13 is fed through a line 18 to a dispersing machine 19 and high-speed shear is applied to uniformly disperse the additives in the kneaded high-concentration demineralized slurry.

Next, this dispersed high-concentration demineralized slurry is fed into a slurry adjustment tank 21 and adjusted to obtain a high-quality adjusted high-concentration demineralized slurry with low viscosity and uniformity. The adjusted high concentration demineralized slurry obtained from the slurry adjustment tank 21 is sent to the line 22, and one part of the adjusted high concentration demineralized slurry is sent to the mixing agitator 1 via the return circulation line 23.
3 for return circulation.

As mentioned above, the dehydrated cake is mixed with the mixer 13,
By mixing and stirring together with adjustment water and additives, a kneaded high-concentration demineralized slurry of good quality with low ash content, low viscosity, and uniformity is obtained. This high-quality kneaded high-concentration demineralized slurry is dispersed in the disperser 19 and adjusted in the slurry adjustment tank 21 as described above.
part is returned via line 23, and the other adjusted high concentration demineralized slurry is returned to line 24 as product high concentration demineralized slurry.
From there, the product is transported to a tank 25 for high-concentration demineralized slurry and stored there.

As described above in detail based on the flow sheet of FIG. 1 showing the embodiment according to the first invention, the following effects can be obtained by the first invention.

〔Effect of the invention〕

(1) Since the coarse grinding mill performs grinding at a low concentration (20 to 60% by weight of coal) where the grinding power is minimum, it can be operated at the point where the grinding power is minimum.

(2) Since the coal is coarsely crushed in a coarse crushing mill and then deashed, the ash produced by the coarse crushing is removed. Therefore, since the ash content has been removed from the highly concentrated demineralized slurry product, the calorific value per unit weight of the slurry increases. Moreover, deashing eliminates the need for clogging due to ash in the burner during combustion, and highly concentrated deashing slurry is stably supplied to the burner nozzle. Furthermore, since a large amount of ash produced conventionally after combustion is removed during combustion, there is no need to increase the size of ash processing equipment, and a large amount of ash processing work is omitted.

(3) Since the ash contained in the low-concentration slurry obtained by coarsely pulverizing coal in a coarse pulverizing mill is deashed and then dehydrated, the dehydration process is carried out smoothly and efficiently.

(4) The kneaded high-concentration demineralized slurry obtained with the mixing agitator is dispersed in the dispersion machine and then adjusted in the slurry adjustment tank (hereinafter abbreviated as "kneading → dispersion → adjustment"), so that the additives are uniformly distributed in the slurry. Moreover, since the concentration is extremely uniform, it is possible to obtain a high-concentration demineralized slurry of high quality and homogenized.

(5) A portion of the high-quality, homogenized, high-concentration demineralized slurry that has been “kneaded → dispersed → adjusted” is returned to the mixer and circulated, resulting in an even product. Moreover, when the plant is started up, it is possible to quickly obtain a highly concentrated product demineralized slurry having a predetermined quality.

(6) Coal is coarsely pulverized in a coarse pulverizing mill, deashed and then dehydrated, so the dehydration performance of the dehydrator is significantly improved, and the water content in the deashed and dehydrated cake is reduced, making it possible to perform subsequent high-concentration dehydration. The moisture content of the ash slurry can be kept low. Further, the adjusted concentration of water can be selected from a wide range.

Next, broken lines and dashed-dotted lines will be explained as additions to the flosheat of the first embodiment of the present invention.

A broken line 26 is a line for returning the dehydrated water discharged from the line 11 obtained by the dehydrator 10 to be used as water to be supplied to the coarse grinding mill 5. In addition, a dashed line 27 indicates a tank 14 for conditioned water so that the dehydrated water obtained by the dehydrator 10 and discharged from the line is used as conditioned water to be supplied to the mixing agitator 13.
This is the line that is fed to.

These lines 26 and 27 can be set to only line 26, only line 27, or line 2 as necessary.
6. Both of the lines 27 may be used at the same time, or, although not shown, the lines may be connected to the dispersion machine 19, the slurry adjustment tank 21, etc. to effectively utilize the dehydrated water.

The following effects can be obtained by the embodiment in which the lines 26 and/or the lines 27 are provided in this manner.

Since the dehydrated water contains colloidal ultrafine coal particles, these are fed to the coarse grinding mill 5 and coarsely ground together with the supplied coal and water.
The high concentration demineralized slurry product has higher pseudoplasticity and better storage stability.

Since the dehydrated water contains colloidal ultrafine coal particles, this is supplied to the mixing agitator 13 and mixed and stirred together with the contents in the mixing agitator 13, so that the rheologin properties become even more pseudoplastic, making it extremely difficult to store. It is possible to obtain highly concentrated demineralized slurry with good stability.

Note that the functions and effects of lines 26 and 27 are similar in the following embodiments, so explanations regarding each embodiment will be omitted.

Next, the second invention of the present invention has been submitted to further improve the first invention.

That is, the feature of the second invention is that in the first invention, the deashed and dehydrated cake obtained from the dehydrator is crushed into fine deashed and dehydrated cakes using a crushing device before being led to the mixing agitator.

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

The embodiment illustrated in FIG. 2 is a flow sheet of the embodiment according to the second invention.

In the embodiment shown in FIG. 2, reference numerals 1 to 27 are equivalent to reference numerals 1 to 27 in the embodiment shown in FIG. 1, so their explanation will be omitted. Reference numeral 28 denotes a crushing device, which crushes the plate-shaped or block-shaped deashing and dewatering cake supplied via the line 12 into small blocks or minute blocks. 28 is this small block or micro block demineralized dehydrated cake (hereinafter referred to as small block demineralized dehydrated cake)
It is a line that transports

In the embodiment shown in FIG. 2, in the case of the embodiment shown in FIG. Alternatively, the demineralized and dehydrated cake in the form of a lump is crushed into small lumps or micro lumps to form a small lump demineralized and dehydrated cake, which is then supplied to the mixing agitator 13 via the small lump demineralized and dehydrated cake line 29. be.

As described above in detail based on the flow sheet of FIG. 2 showing the embodiment according to the second invention, the second invention
The invention provides the following effects in addition to the effects described in (1) to (6) above obtained with the first invention.

(7) In order to supply the demineralized and dehydrated cake to the mixing agitator by crushing it into small pieces, the slurry is supplied to the mixing agitator, which contains adjustment water, additives, and returned ultrafine particles for mixing and agitating the slurry. Uniform mixing and stirring with the adjusted demineralized slurry and adjustment can be carried out smoothly, and a high-quality, uniform, high-concentration demineralized slurry can be obtained.

(8) Furthermore, since homogeneous mixing can be performed smoothly, the production amount of high-concentration demineralized slurry product per unit time is significantly increased, and productivity is therefore improved.

Next, a third invention of the present invention is provided to further improve the first invention.

That is, the feature of the third invention is that in the first invention, the low concentration slurry obtained from the coarse grinding mill is classified into coarse particle-containing low concentration slurry and coarse particle cut low concentration slurry by a classifier before being led to the deashing device. The main purpose of this method is to introduce only coarse cut, low-concentration slurry to the deashing device.

Hereinafter, a preferred embodiment of the third aspect of the present invention will be described in detail with reference to the embodiment illustrated in FIGS. 3 and 4.

The embodiments illustrated in FIGS. 3 and 4 are flow sheets of the first embodiment and the second embodiment according to the third invention.

In the embodiment illustrated in FIGS. 3 and 4,
The same reference numerals among the reference numerals 1 to 27 are equivalent to the same reference numerals among the reference numerals 1 to 27 in the embodiment shown in FIG. 1, so the explanation thereof will be omitted. Reference numeral 9a is a transport line for the coarse cut and low concentration demineralized slurry, 12a is a transport line for the coarse cut and demineralized cake, and 30 is a line for separating the coarse grains in the low concentration slurry supplied from line 6. A classifier for classifying low concentration slurry containing coarse particles and coarse cut low concentration slurry; 31 is a discharge line for the low concentration slurry containing coarse particles classified by the classifier 30; 32 is a line for discharging the low concentration slurry containing coarse particles classified by the classifier 30; This is a transportation line for concentrated slurry.

Such an embodiment as shown in FIG. 3 is similar to the case of the embodiment shown in FIG.
The low concentration slurry obtained in step 1 is supplied to a classifier 30 via line 6 to be classified into coarse particle-containing low concentration slurry and coarse cut low concentration slurry, and only the coarse cut low concentration slurry is deashed through line 32. It is characterized in that it is supplied to the device 7.

As described above in detail based on the flow sheet of FIG. 3 showing the first embodiment according to the third invention,
The invention provides the following effects in addition to the effects described in (1) to (8) above obtained with the first invention.

(9) Since only coarse grain cut low concentration demineralized slurry is classified with a classifier and supplied to the product manufacturing line, there are very few coarse grains in the product high concentration demineralized slurry, resulting in fine or ultrafine coal. As the grain size increases, the rheological properties of the high-concentration demineralized slurry become pseudoplastic, improving storage stability.

(10) Since the product is classified using classified products, the maximum diameter of coarse particles in the highly concentrated demineralized slurry can be arbitrarily selected.
Therefore, it becomes easy to obtain a highly concentrated product demineralized slurry with a desired particle size distribution.

(11) Since the product is classified using a classifier and only the coarse cut, low-concentration demineralized slurry is supplied to the product production line, the amount of coarse particles in the product high-concentration demineralized slurry is extremely small. Therefore, when the coal is combusted in a combustion means such as a boiler, the amount of unburned coal is extremely reduced, there is almost no residue in the boiler, and the combustion efficiency is improved.

Further, FIG. 4 shows a second embodiment of the third invention,
The coarse particle-containing low concentration slurry obtained in the classifier 30 is returned to the coarse grinding mill 5 via the coarse particle containing low concentration slurry return circulation line 31a, and the contained coarse particles are further passed through the coarse grinding mill 5 into fine or fine particles. It is used to crush coal into minute coal particles.

In this way, the second invention of the third invention illustrated in FIG.
In the embodiment, the following effects can be further obtained.

Since the coarse particle-containing low concentration slurry is again coarsely pulverized by the coarse grinding mill 5, the coarse particles in the product high concentration demineralized slurry become even smaller, while the fine and ultra-fine coal particles increase, resulting in a product The rheological properties of the highly concentrated demineralized slurry become very pseudoplastic and the storage stability is improved.

Since the coarse particle-containing low concentration slurry is classified by the classifier 30 and is crushed again by the coarse grinding mill 5, the maximum diameter of the coarse particles in the product high concentration demineralized slurry can be selected very arbitrarily. Therefore, it becomes extremely easy to obtain a highly concentrated product demineralized slurry with a desired particle size distribution.

Since the low concentration slurry containing coarse particles is classified by the classifier 30 and is crushed again by the coarse grinding mill 5, the amount of coarse particles in the product high concentration demineralized slurry is extremely reduced. Therefore, when the coal is combusted in a combustion means such as a boiler, the amount of unburned coal is significantly reduced, the amount of residue in the boiler is also significantly reduced, and the combustion efficiency is further improved.

Next, the fourth invention of the present invention is provided for the purpose of achieving a synergistic effect of the effects of the second and third inventions of the present invention to obtain a high-concentration demineralized slurry of even better quality.

In other words, the feature of the fourth invention is the second invention and the third invention.
In the invention, before introducing the low concentration slurry obtained from the coarse grinding mill to the deashing device, it is classified into coarse particle-containing low concentration slurry and coarse particle cut low concentration slurry using a classifier,
Only the low-concentration coarse cut slurry is led to the deashing device and then to the dehydrator, and the coarse cut cut dehydrated cake obtained from the dehydrator is finely deashed in the agglomeration device before being led to the mixer. The purpose is to crush dehydrated cake into chunks.

Hereinafter, a preferred embodiment of the fourth aspect of the present invention will be described in detail with reference to the embodiment illustrated in FIGS. 5 and 6.

The embodiments illustrated in FIGS. 5 and 6 are flow sheets of the first embodiment and the second embodiment according to the fourth invention.

In the embodiment illustrated in FIGS. 5 and 6,
Those with the same numbers among numerals 1 to 31 are numerals 1 and 3 in the embodiments illustrated in FIGS. 1 to 4.
Since it is equivalent to the item with the same symbol in 1, the explanation will be omitted. Note that 9a is a transportation line for the coarse cut low-concentration demineralized slurry, 12a is a transportation line for the coarse cut demineralized dehydrated cake, and 29a is a transportation line for the small-sized coarse cut demineralized dehydrated cake.

Such an embodiment illustrated in FIG. 5 differs from the embodiment illustrated in FIGS. The slurry is divided into low concentration slurry containing coarse particles and low concentration coarse cut slurry, and only the coarse cut low concentration slurry is supplied to the deashing device 7 from the line 32, and the coarse cut cuts obtained in the dehydrator 10 are deashed. The dehydrated ash cake is supplied to the agglomeration device 28 through the line 12a, and the plate-like or lump-like deashed dehydrated cake is crushed into small or micro-sized dehydrated cakes, which are then passed through the line 36a. It is characterized in that it is supplied to the mixer agitator 13 through.

As described above in detail based on the flow sheet of FIG. 5 showing the embodiment according to the fourth invention, the fourth invention achieves the above (1) and above obtained by the first invention to the third invention.
In addition to the effects described in (11), the following effects can be obtained.

(12) Before deashing and dewatering, classify, dehydrate only the coarse cut low concentration demineralized slurry, and further crush the plate-shaped or lump-like coarse cut cut demineralized dehydrated cake into small lumps using a crusher. Since the slurry is crushed and fed to the mixing agitator, the highly concentrated demineralized slurry is constantly returned and circulated in the mixing agitator, and the slurry is mixed and agitated together to create a good kneading state, resulting in a synergistic effect between these two methods. By this method, a highly concentrated demineralized slurry of extremely high quality can be obtained.

FIG. 6 shows a second embodiment of the fourth invention, and the first embodiment of the fourth invention illustrated in FIG.
By adding the structure and operation described in the flow sheet of FIG. 4 illustrating the second aspect of the third invention, the following effects are aimed at in addition to the effects described in the above to.

Before deashing and dewatering, the low concentration slurry containing coarse particles is classified and sent back to the coarse grinding mill 5 to be crushed again, and only the coarse cut low concentration slurry is deashed and dehydrated. In order to crush the grain cut demineralized dehydrated cake into small pieces in the agglomeration device 35 and supply it to the mixing agitator 13, the mixing agitator 1 is also used.
In step 3, the high concentration demineralized slurry adjusted in the slurry adjustment tank 21 is always returned and mixed and stirred together to form a good kneading state, so the synergistic effect of these produces extremely high quality products with high concentration. Demineralized slurry can be easily obtained.

Next, the fifth invention of the present invention is a further improvement of the third invention of the present invention.

That is, the feature of the fifth invention is that in the third invention, the low concentration slurry obtained from the coarse grinding mill is diluted with dilution water before being led to the classified product, and then this diluted low concentration slurry is led to the classifier. .

Hereinafter, a preferred embodiment of the fifth aspect of the present invention will be described with reference to the embodiment illustrated in FIGS. 7 and 6.

The embodiments illustrated in FIGS. 7 and 8 are flow sheets of the first embodiment and the second embodiment according to the fifth invention.

In the embodiment illustrated in FIGS. 7 and 8,
The same numbers among the reference numerals 1 to 32 are the reference numerals 1 to 32 in the embodiments shown in FIGS. 1 and 7.
Since these are equivalent to those with the same reference numerals, their explanation will be omitted. 9b is a transport line for the coarse cut diluted low concentration demineralized slurry, 12a is a transport line for the coarse cut deashed dehydrated cake, 31b is a discharge line for the diluted low concentration slurry containing coarse grains, and 32a is the coarse cut diluted low concentration slurry. Concentration slurry transport line 33 is a dilution tank that dilutes the low concentration slurry supplied via line 6 to a concentration that is easy to classify with dilution water;
4 is a tank for dilution water, 35 is a dilution water tank 33
A dilution water supply line 35 supplies dilution water for coal 15 to 35 obtained by diluting it in a dilution tank 33.
40% by weight, water 60-85% by weight low concentration slurry (hereinafter referred to as
This line transports diluted low concentration slurry).

Such an embodiment as illustrated in FIG. 7 is similar to the case of the embodiment illustrated in FIG.
The low concentration slurry obtained is led to a dilution tank 33 through a line 6, and is diluted in this dilution tank 33 with dilution water supplied from a tank 34 through a line 35 to a concentration that is easy to classify. That is, it is made into a diluted low concentration slurry containing 15 to 40% by weight of coal. This diluted concentration slurry is passed through a line 36 to a classifier 30.
The slurry is divided into a diluted low-concentration slurry containing coarse particles and a diluted low-concentration slurry containing coarse particles. A feature is that this coarse cut diluted low concentration slurry is supplied to the deashing device 7 from the line 32a.

Further, FIG. 8 shows a second embodiment of the fifth invention,
Return circulation line 3 for the diluted low concentration slurry containing coarse particles obtained in the classifier 30
It is returned to the coarse pulverizing mill 5 via 1c, and the contained coarse particles are further pulverized into fine or fine coal particles by the coarse pulverizing mill 5.

As described above in detail based on the flow sheets of FIGS. 7 and 8 showing the embodiments of the fifth invention, the fifth invention is the above (1) to (12) obtained in the first invention and the third invention. In addition to the effects described in ), the following effects can be obtained.

(13) Before classification with a classifier, the low concentration slurry of 20 to 60% by weight of coal is diluted to a thin diluted low concentration slurry of 15 to 40% by weight of coal, so the classification efficiency in the classifier is improved. It is possible to mass produce highly concentrated demineralized slurry.

Next, the sixth invention of the present invention is a further improvement of the first invention to the fifth invention.

That is, the feature of the sixth invention is that in the fifth invention, the coarse cut demineralized and dehydrated cake obtained from the dehydrator is crushed into fine deashed and dehydrated cakes by the crushing device before being led to the mixing agitator. .

Hereinafter, a preferred embodiment of the sixth aspect of the present invention will be explained in detail with reference to the embodiment illustrated in FIGS. 9 and 10.

The embodiment illustrated in FIG. 9 and FIG.
1 is a flow sheet of a first embodiment and a second embodiment of the invention.

In the embodiments shown in FIGS. 9 and 10, those with the same numbers from 1 to 36 and 9a, 12a, 29a, 31b, 31c, 32a
1 to 36 in the embodiment shown in FIGS. 7 and 8, and 9a,
Since they are equivalent to 12a, 29a, 31b, 31c, and 32a, their explanation will be omitted.

In the embodiment shown in FIG. 9, the coarse cut, deashed and dewatered cake obtained in the dehydrator 10 is fed to the crushing device 28 via the line 12a in the case of the embodiment shown in FIG. The deashing and dewatering cake in the form of a shape or a lump is crushed into a small lump or a fine lump to form a small cut coarse cut deashing and dewatering cake, which is then supplied to the mixer agitator 13 via the line 29a.

As described above in detail based on the flow sheet of FIG. 9 showing the embodiment according to the sixth invention, the sixth invention achieves the above (1) and above obtained by the first invention to the fifth invention.
In addition to the effects described in (13), the following effects can be obtained.

(14) Dilute to make it easier to classify before classification, cut coarse grains by classification, demineralize only the low concentration slurry diluted with coarse grain cuts, and then dehydrate.
In addition, the plate-shaped or lump-like coarse cut deashing dewatering cake of the dehydrator is crushed into small pieces by a crushing device and fed to the mixer, and the mixer is constantly returning the adjusted high-concentration deashing slurry. are returned and circulated and are mixed and stirred together to form a good kneading state, so the synergistic effect of these makes it possible to obtain a high-concentration demineralized slurry of extremely high quality.

Moreover, FIG. 10 is a second embodiment of the sixth invention, and the first embodiment of the sixth invention illustrated in FIG.
By adding the configuration and operation described in the flow sheet of FIG. 8 illustrating the second embodiment of the fifth invention,
In addition to the effects described above, the following effects are aimed at.

Before classification, it is diluted to make it easier to classify, and the coarse particles are cut by classification, and the diluted low concentration slurry containing coarse particles is returned to the coarse particle crushing mill 5 and crushed again. After deashing only the low-concentration slurry, it is dehydrated, and then the dehydrated plate-like or lump-like coarse cut deashing and dewatering cake is crushed into small pieces by a crusher 28 and supplied to the mixer agitator 13. In addition, in the mixing agitator 13, the high-concentration demineralized slurry is constantly returned and circulated and mixed and stirred together to form a good kneading state, so the synergistic effect of these makes it possible to produce extremely high-quality slurry with a low ash content. A highly concentrated demineralized slurry can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of the first embodiment according to the first invention of the present invention, FIG. 2 is a flow sheet of the first embodiment according to the second invention, and FIG. 3 is a flow sheet of the first embodiment according to the third invention. , FIG. 4 is a flow sheet of the second embodiment according to the third invention, FIG. 5 is a flow sheet of the first embodiment according to the fourth invention, and FIG.
The figure is a flow sheet of the second embodiment according to the fourth invention, FIG. 7 is the flow sheet of the first embodiment according to the fifth invention, FIG. 8 is the flow sheet of the second embodiment according to the fifth invention, and FIG. 9 is the flow sheet of the second embodiment according to the fifth invention. FIG. 10 is a flow sheet for the first embodiment according to the sixth invention, FIG. 10 is a flow sheet for the second embodiment according to the sixth invention, and FIG. 11 is a flow sheet for a conventional method for manufacturing low concentration wet high concentration slurry. DESCRIPTION OF SYMBOLS 1...Coal supply storage tank, 2...Coal supply line, 3...Coarse grinding mill supply water tank, 4...Coarse grinding mill supply water supply line, 5...Coarse grinding mill, 6...
Transport line for low concentration slurry, 7... Deashing device, 8...
Ash discharge line, 9...Transportation line for low concentration demineralized slurry, 9a...Transportation line for coarse cut low concentration demineralized slurry, 9b...Transportation line for coarse cut diluted low concentration demineralized slurry, 10...Dehydrator, 11...Discharge line for dehydrated water, 12...Transportation line for deashed and dehydrated cake, 12a...Transportation line for coarse cut deashed and dehydrated cake, 13...Mixing agitator, 14...tank for adjustment water, 15...supply of adjustment water Line, 16... Additive tank, 17... Additive supply line, 18... Transport line for kneading high concentration demineralized slurry, 19... Dispersion machine,
20...Transportation line for dispersed high concentration demineralized slurry, 21
...Slurry adjustment tank, 22...Transportation line for adjusted high concentration demineralized slurry, 23...Return circulation line for returned adjusted high concentration demineralized slurry, 24...Transportation line for product high concentration demineralized slurry, 25...Product high concentration demineralization Slurry tank, 26...Dehydrated water return circulation line, 27...Dehydrated water supply line, 28...Clumping device, 29...Transportation line for small lumpy demineralized dehydrated cake, 29a...Small cut coarse cut demineralized dehydrated cake 30... Classifier, 31... Discharge line for low concentration slurry containing coarse particles, 31a... Return circulation line for low concentration slurry containing coarse particles, 31b... Discharge line for diluted low concentration slurry containing coarse particles, 31c... Discharge line for low concentration slurry containing coarse particles. Return circulation line for grain-containing diluted low-concentration slurry, 32... Transport line for coarse-grain cut low-concentration slurry, 32a... Transport line for coarse-grain cut diluted low-concentration slurry, 33... Tank for dilution, 34...
Dilution water tank, 35... Dilution water supply line, 3
6...Transportation line for diluted low concentration slurry.

Claims (1)

[Claims] 1 Coarsely pulverized coal in water to create a low-concentration coal-water slurry, then the low-concentration coal-water slurry is deashed and then dehydrated, the resulting deashed and dehydrated cake is led to a mixing agitator, and fed by the same mixing agitator. The adjusted water, additives, and the above-described decalcified dehydrated cake are mixed and stirred with the returned adjusted decalcified coal-water slurry to produce a kneaded high-concentration decalcified coal-water slurry, and then the above-mentioned kneaded high-concentration decalcified coal is mixed and stirred. The water slurry is led to a dispersion machine, and the above-mentioned additives are uniformly dispersed in the kneaded high-concentration deashed coal-water slurry using the same dispersion machine, and the obtained dispersed high-concentration deashed coal-water slurry is further adjusted in a slurry adjustment tank. A method for producing a high-concentration coal-water slurry, characterized in that a part of the adjusted high-concentration deashed coal-water slurry is returned and circulated as it is to the mixing agitator.