JPH09302364A - Highly concentrated coal-water mixed fuel and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly concentrated coal-water mixed fuel with high fluidity even if raised in concentration. SOLUTION: This highly concentrated coal-water mixed fuel such as CWM is obtained by mixing water and a dispersant with pulverized coal prepared by grinding coal so as to result in a specified particle size distribution. This mixed fuel also contains such hydrophilic colloid as to afford the pulverized coal with protective effect. The amount of the hydrophilic colloid to be added is as small as possible but enough to exhibit the protective effect on the pulverized coal as hydrophobic colloid particles through adsorption of the hydrophilic colloid to the pulverized coal so as to make its surface hydrophilic, being pref. <1wt.% of the water in this mixed fuel but more than such an amount as to develop mutual coagulation with the pulverized coal, more pref. 10-<4> ppt to 1ppm of the above water (i.e., at levels from ppm order to 10-<4> ppt order), the most pref. 1ppt to 1ppb of the above water (i.e., at levels from ppt order to ppb order).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal / water mixed fuel prepared by mixing coal and water and a method for producing the same. More specifically, the present invention relates to a high-concentration coal / water mixed fuel having good fluidity even at a high concentration and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, as one of the utilization methods of coal, it has been proposed that the coal be pulverized into fine powder and mixed with a small amount of water to form a high-concentration slurry or paste, which can be transported by a pipeline. There is. This is high-concentration coal / water slurry (hereinafter abbreviated as CWM) or high-concentration coal /
It is called a water paste (hereinafter abbreviated as CWP).

In the case of CWM, the particle size distribution of coal is adjusted to increase the concentration to 65 to 70 wt% to provide fluidity, and the coal is burned as it is in an ordinary boiler without being dehydrated. On the other hand, in the case of CWP, the particle size of coal is adjusted to be 6 mm or less, which is slightly larger than the particle size of CWM,
It is kneaded with water together with a desulfurizing agent to have fluidity at a concentration of 70 to 80 wt%. Then, the CWP is extruded from the pipeline into the pressurized fluidized bed boiler by a pump and burned as it is. Because of these, CWM and CW
In P, the water concentration is lowered to 30 to 35 wt% and further sufficient fluidity is required.

The production of these CWMs and CWPs has already been commercialized in a wet production method by wet pulverization. However, a large amount of pulverization power is required for wet pulverization, which increases the production cost. Development of a dry manufacturing method by small dry crushing is desired. Further, in the dry manufacturing method, since pulverized coal is dried at the time of pulverization, it exhibits strong water repellency, and it is difficult to form a slurry. Therefore, in the conventional production of CWM or CWP, when a pulverized coal having a strong water repellency is slurried to facilitate the flow in a pipeline, a CWM having a high concentration, for example, 65 to 70%, is to be obtained. , 0.1 to 1 wt% in the case of a general surfactant-based dispersant, depending on the performance of the surfactant
It is necessary to add some. This improves the wettability of the pulverized coal and prevents the pulverized coal from aggregating in water. Of course, also in the wet manufacturing method, it is necessary to add a large amount of a surfactant in order to improve the wettability of the pulverized coal and prevent the aggregation of the pulverized coal.

[0005]

However, since the cost per unit amount of the dispersant is relatively high in the above-mentioned CWM and CWP, the cost of the dispersant of about 0.1 to 1 wt% is the cost of the CWM and CWP. Approximately 20 to 40% will be occupied.

Various dispersants have been proposed to reduce the dispersant cost. For example, although a dispersant having high performance and capable of reducing the amount added has been developed, the unit price of this dispersant becomes high. In addition, although a dispersant having a low unit price has been developed, it is necessary to add a large amount of this dispersant. For this reason, it is difficult to reduce the cost of the dispersant, and thus the cost of CWM and CWP cannot be reduced.

In the present specification, CWM and CWP are collectively referred to as high-concentration coal / water mixed fuel. Unless otherwise specified, high-concentration coal / water mixed fuel includes high-concentration coal / water slurry. Contains high-concentration coal / water paste.

Therefore, an object of the present invention is to obtain a high-concentration coal-water mixed fuel having good fluidity even if the concentration is increased.
More specifically, it is an object of the present invention to provide a high-concentration coal-water mixed fuel that can reduce dispersant cost and a method for producing the same.

[0009]

As a result of various studies aimed at achieving such an object, the present inventor has found that the high-concentration coal-water mixed fuel is one in which coal particles are dispersed in water.
Since many particles with a size of μm or less occupy, we paid attention to the transition region from colloidal dispersion system or coarse dispersion system to colloidal dispersion system. Therefore, in order to keep the colloid stable, it is sufficient to prevent dispersed particles from binding to each other.
As one of the methods, the present inventor utilizes the affinity between a dispersion medium and a dispersoid to allow a hydrophilic colloid to be adsorbed on the surface of a coal particle, which is a hydrophobic colloid particle, so that it has a property as if it were a hydrocolloid. It was shown to utilize the so-called colloidal protective action which increases stability. However, the slurry of pulverized coal produced by mixing pulverized coal, water and hydrocolloid has an increased viscosity and deteriorated in fluidity. However, by mixing a smaller amount of dispersant than the dispersant normally added to this slurry,
It was found that the viscosity was reduced and a slurry with good fluidity was obtained. This phenomenon is considered to occur due to the following reasons.

(1) By gelation and sol formation with protective colloid Hydrophilic colloid is adsorbed on the surface of pulverized coal particles which are hydrophobic colloid particles, and the surface of pulverized coal particles is wrapped with hydrophilic colloid to be made hydrophilic. Thereby, the hydrocolloid acts as a protective colloid for pulverized coal. Then, the particles of the pulverized coal adsorbing the protective colloid are secondary-bonded by an ionic bond or the like through polyvalent ions such as metal ions eluted from the pulverized coal particles to generate a reversible pulverized coal gel. . It is estimated that this increases the viscosity of the slurry and deteriorates the fluidity.

By mixing the slurry with a dispersant, the secondary bond between the pulverized coals is broken and the pulverized coal gel is returned to the sol. Therefore, the pulverized coal particles are stable without being aggregated in a hydrophilic state by the protective action of the protective colloid. As a result, it is estimated that a high-concentration coal-water mixed fuel with sufficient fluidity can be obtained.

In this case, the amount of the dispersant added is sufficient to break the secondary bonds of the pulverized coal particles, so that the dispersant alone does not add a hydrocolloid and thus the pulverized coal particles are prevented from aggregating. The addition amount of the dispersant can be reduced.

(2) Agglomeration of fine particles by an electrolyte and dispersion due to antagonism of ions Since pulverized coal is a fine particle and has an electric charge, ions of opposite sign (counterion) are attracted to its surroundings to cause electricity. It has a double structure called a double layer and is usually dispersed in a colloidal form due to electric repulsion between counterions. But,
When an electrolyte is added, such as by adding a hydrocolloid, counterions are pushed to the particle surface, reducing the thickness of the microelectric double layer. Then, it can be estimated that the pulverized coal particles enter and collide with each other due to the smaller interparticle distance.

Then, by mixing the slurry with a dispersant, an electrolyte of a type different from the above-mentioned charge material is added. For this reason, two or more kinds of electrolytes are added to the pulverized coal particles, and the cohesive force of the pulverized coal particles is suppressed by the ion antagonistic action. As a result, it is estimated that a high-concentration coal-water mixed fuel with sufficient fluidity can be obtained.

In this case, the amount of the dispersant added is sufficient to cause the pulverized coal particles to have an antagonism of ions, so that compared with the case where the dispersant alone is used to prevent the aggregation of the pulverized coal particles without adding the hydrocolloid. The amount of dispersant added can be reduced.

(3) Agglomeration of fine particles by a polymeric substance and dispersion by bilayer adsorption of a dispersant Since a hydrocolloid is a water-soluble polymeric substance and has a large number of hydrogen bonding groups, electricity and ions Adsorbs to pulverized coal particles by hydrogen bonding groups regardless of When a small amount of polymer is adsorbed on the pulverized coal particles, it is not adsorbed on the entire particle surface but is adsorbed sparsely. Therefore, a part of the polymer adsorbed on the other particles is adsorbed on the vacant portion of the particle surface, and one polymer is bonded to two or more particles. From this, it can be estimated that the pulverized coal particles are aggregated. This is a phenomenon called "crosslinking aggregation".

When the dispersant is mixed with this slurry, the dispersant ions are adsorbed in a bilayer on the vacant portions of the particle surface. Therefore, the pulverized coal particles have an electric charge as a whole and are dispersed. This allows
It is estimated that a high concentration coal-water mixed fuel with sufficient fluidity can be obtained.

Further, by mixing the dispersant with the pulverized coal particles that have undergone cross-linking aggregation, the polymer that is joined to one pulverized coal particle is also joined to the vacant portion of the surface of the same particle. Then, a large number of macromolecules are entwined intricately around each particle to form a thread-like macromolecule, which covers the entire surface of the pulverized coal particles. Therefore, the polymer that bonds the particles to each other is reduced, and the particles repel each other. As a result, it is estimated that a high-concentration coal-water mixed fuel with sufficient fluidity can be obtained.

In this case, the dispersant is sufficient to fill the empty portions of the pulverized coal particles with the dispersant itself or the thread-like polymer, so that the dispersant alone is used without adding the hydrocolloid. The amount of the dispersant added can be reduced as compared with the case of preventing the aggregation of.

It should be noted that each of the above-mentioned phenomena occurs not only when any one of them occurs, but also when the phenomena occur simultaneously and in association with each other, or even when the addition of the dispersant is significantly reduced for other reasons. It is considered that liquidity may have been obtained.

The present invention has been made based on such knowledge, and the high concentration coal-water mixed fuel according to claim 1 is
A high-concentration coal / water mixed fuel prepared by mixing pulverized coal obtained by pulverizing coal into a predetermined particle size distribution, water, and a dispersant contains a hydrocolloid that has a protective effect on the pulverized coal. In the method for producing a high-concentration coal / water mixed fuel according to claim 5, a high-concentration coal / water mixed fuel is produced by mixing pulverized coal obtained by pulverizing coal into a predetermined particle size distribution, water and a dispersant. In the method, a hydrocolloid that produces a protective effect on pulverized coal is added and mixed.

Here, the addition amount of the hydrocolloid can be slightly decreased when the hydrocolloid having a protective effect on the pulverized coal and the surfactant are added at the same time. It was not as effective as above. Further, when the protective colloid was added first with the surfactant, the amount of the surfactant used did not decrease.

Therefore, in the method for producing a high-concentration coal / water mixed fuel according to claim 6, the hydrocolloid is added to the mixture of pulverized coal and water, and then the dispersant is added. Therefore, by adding and mixing the hydrocolloid to the mixture of pulverized coal and water, a gel-like pulverized coal slurry is generated. By adding and mixing a dispersant to this slurry, the pulverized coal slurry becomes a sol. The reason why this phenomenon occurs is as described above. This allows
A high-concentration coal-water mixed fuel with a smaller amount of dispersant added will be produced. For example, as is clear from the actual measurement data of FIG. 14, for example, 0.4 wt.
% To obtain a high concentration coal-water mixture fuel with the same fluidity as the conventional high concentration coal-water mixture fuel with 1% dispersant added.
By adding ppm hydrocolloid prior to the dispersant, the addition amount of the dispersant is 1/2 to 1 / of the conventional addition amount.
It can be reduced to 4.

The addition amount of the hydrocolloid is an amount sufficient to exert a protective effect of adsorbing on the coal fine particles which are the hydrophobic colloid particles and hydrophilizing the surface thereof, and the amount thereof is preferably as small as possible. An amount of less than 1 wt% of the water content of the high-concentration coal-water mixed fuel, as in 2 and 8, and an amount greater than the amount that causes mutual coagulation with pulverized coal, more preferably a high-concentration coal as in claims 3 and 9. -Amount of water mixed fuel of 1 ppm or less and 10 ^-4 ppt or more (that is, p
pm order to 10 ^-4 ppt order), most preferably 1 ppb or less and 1 ppt or more of the water content of the high-concentration coal-water mixed fuel according to claims 4 and 10 (that is, the amount of ppt order to ppb order). Is to

When the addition amount of the hydrocolloid is increased, the binding between the pulverized coals becomes strong due to the strong gelation. Therefore, the addition amount of the dispersant must be increased in order to break this bond, and Reduction effect diminishes. On the other hand, if the amount is too small, the hydrophobic colloid, on the contrary, causes a sensitizing action that makes it unstable. Specifically, as is clear from the actual measurement data of FIG. 13, in the case of obtaining a CWM of 70% concentration, if the amount of colloid added to water exceeds 10 ppm, the fluidity starts to deteriorate. Addition amount of hydrocolloid is 10 ^-4 pp
If it is less than t and too small, the fluidity is deteriorated.

Further, in the method for producing a high-concentration coal-water mixed fuel according to claim 7, the pulverized coal is finely pulverized by further grinding the pulverized coal obtained by dry pulverization so that the pulverized coal is pressed against each other and rubbed against each other. It is assumed that the corners of the charcoal were scraped to make them spherical and ultrafine particles were generated. As a result, high-concentration coal / water fuel with higher fluidity and concentration is produced.

Pulverized coal obtained by pulverizing coal with a mill is fine particles having a predetermined particle size or less and mostly 100 μm or less. The shape is as shown in FIGS.
As shown in, it is a square polyhedron of irregular shape,
The particles are relatively large for high-concentration coal / water mixed fuel. Further, the particle size distribution (based on mass) is, as shown by a circle in FIG. 12, about 100% or less is about 93%, 10 μm or less is about 15%, and 1 μm or less is less than 1%. The fine particle component of 10 μm or less is insufficient.

However, the pulverized coal is rubbed and pressed against each other,
The pulverized coals are rubbed against each other to be ground, and as shown in FIGS. 5 (B) and 7, the pulverized coals are rounded to be spherical and have a small surface area. In addition, the cut corners become ultrafine particles having a size of 1 μm or less. Therefore, the particle size distribution (based on mass) is 100 μm as shown by the ● mark in FIG.
m or less is about 100%, 10 μm or less is about 45%, 1 μm
The following is about 17%, which satisfies the value required for CWM. Then, it is possible to obtain the CWM in a state where the gaps between the pulverized coals that have been made spherical are filled with the ultrafine particles. The spheroidizing of the pulverized coal of the present invention can also be applied to COM production.

That is, since the pulverized coal is rounded and spherical to reduce the surface area, the amount of ultrafine particles required to fill the gaps between the pulverized coals is reduced. Moreover, since the easily shaving areas are scraped off, the main particles are spheroidized, but the initial particle diameter does not become extremely small, and ultrafine particles can be generated. On the other hand, the scraped corners become ultrafine particles, which are filled in the gaps between the pulverized coal particles. Therefore, a sufficient amount of ultrafine particles is filled in the gap between the pulverized coals. As a result, high-concentration coal
Wide particle size distribution required for the water-mixed fuel to gain fluidity,
That is, spheroidized relatively large particles to extremely fine particles can be easily generated by spheroidizing pulverized coal to adjust the particle size distribution suitable for high-concentration coal and water mixed fuel. Then, moisture is expelled from the gaps between the pulverized coals, and a high-concentration CWM or CWP can be obtained. Further, since the surface of the pulverized coal is adhered so that the ultrafine particles cover the pulverized coal to cause a lubricating effect, it is possible to obtain a CWM or CWP having high fluidity. As shown in the actual measurement data of FIG. 15, the CWM that has been spheroidized (marked with ▲) is the CWM that is not used (marked with Δ).
It is clear that it is more liquid than. Moreover, since it is not necessary to prepare and mix a large amount of ultrafine particles, C
Manufacturing of the WM or CWP is simplified, and the manufacturing cost can be reduced.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on the best mode shown in the drawings.

FIG. 1 shows an example in which the high-concentration coal-water mixed fuel of the present invention is CWM. A dry manufacturing system for manufacturing this CWM includes a mill 3 that grinds coal 1 into pulverized coal 2, a mixed water jet pump 5 that moisturizes pulverized coal 2 to form wet pulverized coal 4, and wet pulverized coal. Spheroidizing device 6 for mixing 4 with hydrocolloid 7 to produce pulverized coal gel 8
And a stirrer 11 that mixes the pulverized coal gel 8 with the dispersant 9 to produce the CWM 10. That is, the present invention provides a high-concentration coal-water mixed fuel such as CWM, which is obtained by mixing pulverized coal 2 obtained by pulverizing coal 1 into a predetermined particle size distribution, water and a dispersant 9, and pulverized coal 2 Hydrocolloid 7, which produces a protective effect, is added.

The mill 3 is usually called a dry type mill and is generally used for producing pulverized coal for coal boilers such as coal-fired power plants. Pulverized coal 2 is obtained by pulverization by the mill 3. Mixed water jet pump 5
The high pressure water and air through the orifice 21 to the nozzle 22
The pulverized coal 2 is sucked into the wet pulverized coal 4 by being agitated by vigorous stirring with strong jet water.

The wet pulverized coal 4 is continuously and smoothly fed into the spheroidizing device 6 together with water and the hydrocolloid 7. As shown in FIG. 4, the spheroidizing device 6 is a disk-shaped rotating disk 24 as a first member that is rotated by a drive source such as a motor, and a rotating disk 24 of substantially the same size and shape as the rotating disk 24. A fixed disk 25 as two members and a funnel 26 attached to the central portion of the fixed disk 25 are provided. The respective facing surfaces of the rotating disk 24 and the fixed disk 25 are faced in parallel with each other with a slight gap. A through hole is formed in the central portion of the fixed disk 25. A small diameter portion of the funnel 26 is attached to the opening of the through hole.

Then, with the rotating disk 24 rotated, the wet pulverized coal 4 together with water and the hydrocolloid 7 are funnels 2.
Pour into 6. As a result, the wet pulverized coal 4 is fixed to the fixed disk 2
It passes through the through hole 5 and is sandwiched between the facing surfaces of the rotary disk 24 and the fixed disk 25, and is moved to the outer peripheral side by centrifugal force while being rubbed, pressed and rubbed by rotation. At this time, since the particles of the wet pulverized coal 4 contact and rub against each other,
As shown in FIG. 5 (B), the corners of the particles are scraped to be spherical and ultrafine particles are generated. Then, the water added at the same time causes the ultrafine particles to enter the gap between the large particles,
A CWM is generated. Here, as shown in FIG. 7, the CWM has particles whose corners are spheroidized,
It has a sufficient amount of ultrafine particles. Further, in the present embodiment, water is added in the spheroidizing device 6, but it does not have to be added.

Although the facing surfaces are flat in this embodiment, they may be shaped to have irregularities such as grooves and protrusions. According to this structure, the wet pulverized coal 4 is rubbed and pressed in a complicated manner, and the spheroidization and the generation of ultrafine particles are more reliably performed.

Further, in the spheroidizing device 6, the hydrocolloid 7 is mixed with the particles of the wet pulverized coal 4, so that the particles of the pulverized coal 4 are secondary-bonded to each other, or the pulverized coal 4 is agglomerated due to the attractive force between the particles, Cross-linking aggregation of molecules occurs. For this reason, the wet pulverized coal 4 is gelated, so that the jelly-like pulverized coal gel 8 is generated.

Here, the addition amount of the hydrocolloid 7 may be an amount sufficient to cause a gelling action, but if it is too much, gelation proceeds and a large amount of the dispersant 9 is added to form a sol. I need it. This makes it impossible to reduce the cost of the CWM 10 and the like by reducing the use of the dispersant 9. For example, as shown in FIG. 13, a density of 70.6%
The amount of surfactant as a dispersant in CWM of
When it is set to 0.2 wt% of / 2, if the addition amount of the hydrocolloid exceeds 10 ppm of CWM, the fluidity deteriorates, and it becomes necessary to add a large amount of dispersant 9, which is the same as the conventional addition amount. come. Also, hydrocolloid 7
The lower limit of the addition amount of is larger than the amount that causes mutual coagulation with pulverized coal. If the amount of the hydrocolloid added is smaller than this, a sensitizing effect occurs. For example, as shown in FIG.
When the amount is less than 10 ^-4 ppt in a CWM having a concentration of 70.6%, the fluidity is deteriorated, so the amount is preferably more than 10 ^-3 ppt order. Therefore, the addition amount of the hydrocolloid 7 is preferably 1 wt% with respect to the water added to the CWM when, for example, a CWM having a concentration of 70% is obtained.
% And more than the amount that causes mutual coalescence of pulverized coal, more preferably from ppm order to ppt order, for example, 1 ppm to 10 ^-3 ppt, most preferably ppt.
Order to ppb order, for example 1ppt to 1pp
b. In this case, the amount of the surfactant used can be reduced as compared with the conventional one, and in particular, when it is added in the range of 1 ppt to 1 ppb, about 1/3 of the conventional surfactant is sufficient. The suitable addition amount of the hydrocolloid 7 is slightly different depending on the CWM concentration, but if it is set from the ppt order to the ppb order, the use of the dispersant is almost independent of the CWM concentration. At least 1/2 the amount of conventional
It can be about 1/4.

Further, when an extremely inexpensive ion neutralizing agent having a low surface active effect is used as the dispersant 9, even if about 1 wt% of the hydrocolloid 7 is added, a large amount of the ion neutralizing agent can be used to form a sol at a low cost. . However, when an expensive surfactant having a high surface-active effect, which has been conventionally used, is used as the dispersant 9, the addition amount of the hydrocolloid 7 is 10
0 ppm or less. As a result, the amount of the surfactant used can be reduced to 1/2 to 1/4 of the conventional amount, and the amount of the hydrocolloid 7 itself is 100 ppm or less, so that the addition amount can be extremely reduced.

As the hydrocolloid 7, those exemplified in Table 1, Table 2 and Table 3 can be used. Then, typically, gelatin, gum arabic, casein, glue, tragacanth, albumin, dextrin, starch, hydroxyethyl cellulose, polyvinyl alcohol, methyl cellulose and the like are preferably used. However, the present invention is not limited to these, and other kinds of hydrocolloids 7 may be used as long as they have a protective action on the wet pulverized coal 4 which is a hydrophobic colloid particle. Furthermore, hydrocolloid 7 to be added
Is not limited to a single type, and a plurality of types of hydrocolloids 7 may be added simultaneously or separately.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

Further, the pulverized coal gel 8 is continuously and smoothly fed into the stirrer 11. The dispersant 9 is put into the stirrer 11 and sufficiently stirred and mixed with the pulverized coal gel 8. Then, the secondary bond between the particles of the pulverized coal gel 8 is broken, the antagonism of the ions occurs in the pulverized coal particles, the dispersant 9 itself or the thread-like polymer fills the empty portions of the pulverized coal particles. The pulverized coal is turned into a sol. Then, the pulverized coal particles are stable in the sol state without agglomeration. Accordingly, it is possible to obtain the CWM 10 having the fluidity suitable for transportation by the pipeline.

As the dispersant 9, a surfactant is generally used, but the dispersant is not limited to this, and a chelating agent that incorporates polyvalent ions mainly composed of metal ions eluted from the pulverized coal particles and the above-mentioned polyvalent ions can be used. An ionic neutralizing agent, etc., which is hydrated to prevent ionic bond with the protective colloid, and which shows a so-called sol-forming action of returning the reversible gel-like pulverized coal particles to the sol again. Other dispersion stabilizing substances may be used. As the chelating agent, for example, ethylenediaminetetraacetic acid (EDTA) or the like can be used. Further, as the dispersant 9, a shielding agent that prevents ionic bonds between the pulverized coal particles may be used.

According to the CWM manufacturing system configured as described above, the pulverized coal 2 is first pulverized by the mill 3.
Get. Next, the pulverized coal 2 is mixed with the mixed water jet pump 5
Is added to obtain wet pulverized coal 4 in a short time. Then, a hydrocolloid 7 and water are added to the wet pulverized coal 4 and the particles are rubbed together by a spheroidizing device 6 to achieve secondary bonding and agglomeration of the pulverized coal particles and to spheroidize them to obtain a pulverized coal gel 8. A dispersant 9 is added to the pulverized coal gel 8 and mixed by a stirrer 11 to break the secondary bonds and agglomerations of the pulverized coal particles, and thus the CWM.
Get 10. The CWM can be adjusted by adjusting the amount of water added by the mixed water jet pump 5 and the spheroidizing device 6.
Ten density adjustments can be made.

According to this embodiment, since the hydrocolloid 7 is added to the wet pulverized coal 4 and then mixed with the dispersant 9,
The mixing amount of the dispersant 9 can be significantly reduced as compared with the case where the hydrocolloid 7 is not added. Specifically, FIG.
The CWM concentration of 70.6 wt% (Plot ○ ●), as shown in (Plot ○ ●), the hydrocolloid 7 was not added and only the dispersant 9 was added.
The same viscosity as when about 4% was obtained by adding about 1 ppm of the hydrocolloid 7 in the above-mentioned manufacturing system, and the addition amount of the dispersant 9 at that time was 1/2.
It was possible to reduce to ~ 1/4. Therefore, by reducing the amount of dispersant 9 used and reducing the cost, C
The cost of the WM 10 can be reduced.

Further, according to this embodiment, the spheroidizing device 6 is used.
Since the pulverized coal particles are spheroidized, water easily enters between the particles of the pulverized coal. Therefore, since the hydrocolloid 7 and the dispersant 9 are efficiently dispersed around the pulverized coal particles, the formation of the protective colloid and the gelation of the pulverized coal due to the secondary binding / aggregation and its sol formation action are promoted, The addition amounts of the hydrocolloid 7 and the dispersant 9 can be further reduced. At the same time, the pulverized coal particles are spheroidized to adhere to the surface of the pulverized coal so as to be covered with the ultrafine particles to generate a lubricating effect, so that the fluidity of the CWM can be improved. Specifically, as shown by the triangle mark in FIG. 15, the CWM (marked with spheroidization) is higher in fluidity than the CWM without the sphere (marked with triangle).

Further, according to this embodiment, since the CWM is manufactured by the dry manufacturing method, the manufacturing time is shortened to 1/2 to 1/5 as compared with the case of the wet manufacturing method, and the driving power is 1%. It can be reduced to about / 3. Moreover, as shown by ▲ □ in FIG. 15, C produced by the dry manufacturing method is used.
Even a WM can have the same fluidity as a CWM produced by a wet manufacturing method if it is spheroidized.

By the way, in the present embodiment, water is added to the pulverized coal 2 to form the wet pulverized coal 4, and further water is added by the spheroidizing device 6 to form the CWM. As long as a CWM having a predetermined concentration is finally obtained, water may be added only once or divided into two times. Further, the pulverized coal 2 obtained by the mill 3 can be poured into the spheroidizing device 6 together with water. In this case, the air-fuel mixture jet pump 5 becomes unnecessary, and the equipment can be reduced.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

For example, in the present embodiment, the case where the present invention is mainly applied to the dry CWM production is explained. However, regarding the technique for improving the fluidization of the high concentration coal / water mixed fuel by adding the hydrocolloid, the wet production is explained. It can also be applied to the law. Further, the improvement of the fluidity of the pulverized coal slurry by spheroidizing the pulverized coal can be applied to COM.

Although the disk on which the funnel 26 of the spheroidizing device 6 is attached is the fixed disk 25, it may be a rotating disk and the other disk may be a fixed disk. Further, both discs may be rotated. If both discs are rotated in opposite directions, the relative speed between the discs will be higher than in the case where only one disc is rotated, so that spheroidization can be performed more reliably. Further, the rotating disk may be rotated while being eccentric, or may be slid without rotating.

As shown in FIG. 8, the rotating disk 24 'and the fixed disk 25' of the spheroidizing device 6 are installed so that their facing surfaces are substantially vertical, and the screw is inserted into the through hole of the fixed disk 25 '. The feeder 27 may be attached. Then, by rotating the screw of the screw feeder 27, the wet pulverized coal 4 is fed between the rotating disk 24 'and the fixed disk 25'. Also, the rotating disk 2
A water supply pipe 28 is installed between the 4'and the fixed disk 25 '. The water supply port of the water supply pipe 28 is located at the center of the facing surface. As a result, the rotating disk 24 'and the fixed disk 2 are
Water is supplied to and mixed with the wet pulverized coal 4 sandwiched between 5 '.

Further, as shown in FIG. 9, the spheroidizing device 6
May have a structure including two flat plates 31 and 32 as a first member and a second member facing each other with a slight distance therebetween. In this structure, one flat plate 31 is fixed and the other flat plate 32 is slid in the direction parallel to the facing surface, or the flat plates 31 and 32 are moved in the sliding direction. Then, the wet pulverized coal 4 is supplied from above the spheroidizing device 6 and sandwiched between the flat plates 31 and 32. Next, the flat plates 31 and 32 are slid relative to each other, whereby spheroidization and generation of ultrafine particles can be performed.

Further, as shown in FIG. 10, the spheroidizing device 6 includes a cylindrical member 34 as a first member, and the cylindrical member 3
The shaft 35 as the second member which is penetrated by the gap fitting 4
It may have a shape including and. In this structure, one or both of the cylindrical member 34 and the shaft 35 are rotated or slid in the axial direction. And the cylindrical member 3
By sandwiching the wet pulverized coal 4 between the shaft 4 and the shaft 35 and relatively moving them, spheroidization and generation of ultrafine particles can be performed. It is also possible to form a concave portion or a convex portion along the axial direction or the circumferential direction on the inner peripheral surface of the cylindrical member 34 and the outer peripheral surface of the shaft 35, or to form a spiral concave portion or a convex portion.
Further, when the wet pulverized coal 4 is made to flow inside the cylindrical member 34, it is forced to flow from one of the gaps, or one of the cylindrical member 34 and the shaft 35 is made larger in diameter than the other to provide a taper. This can be done more easily.

Further, as shown in FIG. 11, a member as a second member having a columnar member 36 as a first member and a recess 37a for accommodating the outer peripheral surface of the columnar member 36 with a slight gap. 37 may be used as the shape. In this structure, the column member 36 and the member 37 having the recess 37a are provided.
One or both are rotated relative to each other or moved to slide axially. Then, by sandwiching the wet pulverized coal 4 between the recess 37a and the columnar member 36 and relatively moving them, spheroidization and generation of ultrafine particles can be performed.

In the structures shown in FIGS. 9, 10, and 11, the opposing surfaces are made smooth, but they may have a shape in which irregularities such as grooves and protrusions are formed. Further, a shape in which a plurality of protrusions scattered on a straight line at predetermined intervals may be arranged in parallel. According to these shapes, the wet pulverized coal 4 is rubbed in a complicated manner, and the spheroidization and the generation of ultrafine particles are performed more reliably.

In the present embodiment, the distance between the facing surfaces is constant, but the distance may be changed. In this case, the moist pulverized coal 4 can be pressed by slightly reducing the interval.

On the other hand, in the present embodiment, the CWM is manufactured by a dry method, but in the case of wet crushing, for example, as shown in FIG. 2, a rotary wet crusher 12 is provided with coal 1, water and hydrocolloid 7. Add and grind to produce pulverized coal gel 8.
Then, the dispersant 9 is added to the pulverized coal gel 8 and the stirrer 1 is added.
Mix at 1. Also according to this manufacturing method, the hydrocolloid 7 is added to the pulverized coal to produce the pulverized coal gel 8, and the pulverized coal gel 8 is sol-ized with the dispersant 9 to obtain the CWM 10. Therefore, the amount of the dispersant 9 added Can be reduced.

Further, although the CWM is manufactured in each of the above-described embodiments, the CWP is not limited to this, and the CWP can be manufactured. The manufacturing system in this case is as shown in FIG.
Coarse crusher 13 for crushing coal 1, sieve 15 for selecting pulverized coal 14 having a predetermined particle size or less, kneader for kneading pulverized coal 14, water, desulfurizing agent and hydrocolloid 7 to produce CWP 16. 17 and a tank 18 for storing the CWP 16,
A CWP pump 19 that discharges the CWP 16 is provided. In this manufacturing system, the dispersant 9 is added in the middle of the kneading machine 17. That is, the pulverized coal 14, water, the desulfurizing agent, and the hydrocolloid 7 are put into the kneader 17 and kneaded, and the pulverized coal gel is generated in the upstream portion of the kneader 17. Then, the pulverized coal gel is mixed with the dispersant 9 to form a sol, and the CWP 16 is manufactured. According to this manufacturing system as well, the hydrocolloid 7 is added to the pulverized coal 14 to produce the pulverized coal gel, and the pulverized coal gel is solized with the dispersant 9 to obtain CWP16. Can be reduced. Furthermore, the pulverization technique of pulverized coal can be applied to the production of COM.

(Example 1) Experiment for confirming generation of ultrafine particles and particle size distribution by spheroidizing pulverized coal using a mill 3, an air-mixed water jet pump 5 and a sphering device 6 shown in FIG. I went.

Pulverized coal 2 was obtained by a dry type rigid mill 3. Next, this pulverized coal 2 was mixed with water by a mixed water jet pump 5 to obtain a wet pulverized coal 4. The shape of the particles of the wet pulverized coal 4 at this time is shown in the SEM photograph of FIG. As shown in the figure, the particles were angular polyhedra composed of irregular shapes and were relatively large. Further, the particle size distribution was in the state of ◯ mark in FIG.

Hydrophilic colloid was added to the wet pulverized coal 4 and rubbed with a spheronizer 6 to form a pulverized coal gel, and a dispersant was mixed with this to obtain a CWM. The shape of the particles of this CWM is shown in the SEM photograph of FIG. 7. As shown in the same figure, the corners of the pulverized coal 2 were shaved and spheroidized to reduce the surface area. The particle size distribution (based on mass) was in the state of ● in FIG. That is, as is clear from the figure, 100 μm
The following values were about 100%, about 45% for 10 μm or less and about 17% for 1 μm or less, which satisfied the particle size distribution required for CWM.

Example 2 A CWM manufacturing experiment using a protective colloid was conducted using the mill 3, the mixed water jet pump 5, and the spheroidizing device 6 shown in FIG.

First, in order to investigate the effect of the protective colloid, the wettability of the pulverized coal was confirmed by comparing about 30% of water obtained by adding a small amount of the hydrocolloid 7 to ordinary pulverized coal, and not adding the hydrocolloid. did. According to this, when not added, the pulverized coal initially feels like repelling water, and does not easily resemble water even after kneading. However, in the case of adding the hydrocolloid, the feeling of repelling water at the beginning was weak, and the kneading state was relatively easy. In this way, after confirming that the hydrocolloid improves the wettability of pulverized coal, a CWM production experiment using a protective colloid was conducted.

As shown in FIG. 13, 70% CWM
In producing the above, as the hydrocolloid 7, hydroxyethyl cellulose (HEC), polyvinyl alcohol, methyl cellulose, tragacanth, casein and gelatin were used and added to the water supplied by the spheroidizing device 6. The addition amount was reduced from% order to ppm and ppt order with respect to water, the effect of the protective colloid was confirmed, and an appropriate amount was found. The specific addition amount of the hydrocolloid 7 is 1 wt% with respect to water, 10 ppm, 1 ppm, 1 ppb,
1 ppt, 10 ^-3 ppt, 10 ^-6 ppt, 10 ^-9 ppt
And The coal used was Hunter Valley (Australia), the dispersant 9 was a surfactant, the amount added was 0.2 wt% with respect to CWM, and the CWM concentration was 70%.
wt%. Then, the viscosity of the manufactured CWM was measured at a temperature of 25 ° C., and the relationship with the addition concentration of the hydrocolloid was investigated. As a viscometer, a rotational viscometer Rheomat 1
Using 15 (manufactured by Contrabass, Switzerland), the number of revolutions was raised by a program and kept constant, and then lowered to perform automatic measurement. The result is shown in FIG. Similar results were obtained when the coal was changed to another type.

As a result, as shown in the figure, the fluidity is good when the addition amount of the hydrocolloid is in the range of 10 ⁻⁴ ppt to 10 ppm with respect to water, and particularly the fluidity is the best in the range of 1 ppt to 1 ppb. was. Also, less than 10 ^-4 ppt or 1
In the range of more than 0 ppm, the fluidity deteriorated and the viscosity measurement result became unstable. The addition amount of the hydrocolloid is shown with respect to the water of CWM, but the addition effect is pp.
CWM as it is demonstrated on m-order and ppt-order
There is no difference in effect even if the same amount is added to the whole.

(Embodiment 3) When a CWM is manufactured using the mill 3, the mixed water jet pump 5 and the spheroidizing device 6 shown in FIG. 1, with and without addition of the hydrocolloid 7. About the change that the added amount of dispersant gives to viscosity CWM
Experiments were carried out for each concentration.

In the experiment, Hunter Valley (produced in Australia) was used as coal, and HEC was 1 pp as hydrocolloid 7.
m was added and the viscosity was measured at 25 ° C. Then, the relationship between the viscosity and the added amount of the dispersant 9 was examined for the manufactured CWM. The result is shown in FIG. The CWM concentration is 6
In the case of 9.3 wt%, only the case where the hydrocolloid 7 was added was carried out, and therefore, it is shown as a reference. Also, in the figure,
The unit of the added amount of the dispersant 9 is wt% with respect to the CWM.

As is clear from the figure, the CWM concentration is 7
When 0.6% does not use hydrocolloid 7 which has a protective effect on pulverized coal and the current addition amount is 0.4%, the viscosity is 1200 mPa · s, and the addition amount is 0.3% and 0.2%. When reduced to%, the viscosities show 1600 and about 4500 mPa · s, respectively. On the other hand, in the case of using the protective colloid, the viscosity is 1200 mPa · s, which is a substantially constant value even if the amount of the surfactant added is reduced from 0.4 to 0.3, 0.2 and 0.16%. Has become. Also,
At a CWM concentration of 67.1%, no hydrocolloid was added, and a viscosity of 450 mPas when the amount of surfactant added was 0.4%.
・ S, similarly, it becomes 600 mPa · s at 0.2% and about 2800 mPa · s at 0.1%. On the other hand, in the case of adding the hydrocolloid, even if the addition amount is reduced to 0.13%, the viscosity becomes almost constant value of 400 mPa · s, and the CW
900 mPa · s (± 300 mP) which is the standard value of M viscosity
The addition amount of a.s) is less than 0.1%.

As described above, it is possible to reduce the amount of the surfactant by using the hydrocolloid which has the protective effect on the pulverized coal. The reduction ratio is about 1 / 2.5 to obtain the viscosity when not used, and the CWM concentration is 7
If it is sufficient to clear the reference viscosity value in the case of 0.0% or less, it can be set to 1/3 or less.

(Example 4) When the CWM is produced using the pulverized coal obtained by the mill 3 shown in FIG. 1, only the spheroidizing device 6 is used, and the mixed water jet shown in FIG. The effect of spheroidizing of pulverized coal on the fluidity and viscosity was examined by using only the pump 5 and by using the wet manufacturing method.

In this experiment, Hunter Valley charcoal (Australia) was used to perform spheroidizing treatment using a spheroidizing device 6, and then a sodium polystyrene sulfonate-based surfactant as a dispersant 9 was added to a CWM of 0. The one manufactured by adding 0.4 wt% and the other one manufactured by adding 0.2 wt% of the half thereof were manufactured. Then, the addition amount of the dispersant 9 is 0.2 wt.
In the case of%, 1 ppm of hydrocolloid 7 was added in advance. In addition, in the case where only the mixed water jet pump 5 is used and the spheroidizing device 6 is not used and the case where the wet manufacturing method is used, the addition amount of the dispersant 9 is set to 0.4 wt% of the current C
A WM was manufactured. Workworth (Australia) was used as the coal at these times. Then, the viscosity of the manufactured CWM was measured, and the relationship with the coal concentration was investigated. The result is shown in FIG. The measurement temperature is 25 ° C.
And

As shown in the figure, when only the spheroidizing device 6 is used, the CW in which the amount of the dispersant 9 added is halved.
Even with M (-), addition of 1 ppm of Hydrocolloid 7 gave fluidity equivalent to that of CWM (-) with the current amount of dispersant added. In addition, the current amount of CWM added dispersant
Comparing the two, the CWM spheroidized by the spheronizer 6
(▲ mark) was higher in fluidity than CWM (Δ mark) which was not spheroidized using only the mixed water jet pump 5. Moreover, the CWM (marked with ▲) using only the spheroidizing device 6 is
The fluidity was equivalent to that of CWM (square mark) produced by the wet manufacturing method. From these facts, it is possible to manufacture a CWM having good fluidity by spheroidizing pulverized coal.

[0075]

As is apparent from the above description, the high-concentration coal / water mixed fuel according to claim 1 is formed by mixing pulverized coal obtained by pulverizing coal into a predetermined particle size distribution, water, and a dispersant. The high-concentration coal-water mixed fuel comprises a hydrocolloid that has a protective effect on pulverized coal, and the method for producing a high-concentration coal-water mixed fuel according to claim 5 pulverizes coal into a predetermined particle size distribution. In the method of producing a high-concentration coal / water mixed fuel by mixing the pulverized coal, water and a dispersant, a hydrocolloid that produces a protective effect on the pulverized coal is added and mixed. The amount of the agent added is such that the secondary bond between the pulverized coals is destroyed, or the amount of antagonism of ions is caused in the pulverized coal particles, or the pulverized coal particles by the dispersant itself or the thread-like polymer. Just fill in the empty space Since suffice, it is possible to significantly reduce the amount of dispersing agent as compared with the case to prevent aggregation of a conventional pulverized coal particles only dispersant as. For example, 70
In the case of producing CWM having a concentration of%, as is clear from the actual measurement data shown in FIG. 14, the fluidity of CWM was not impaired even when the amount of surfactant used was about 1/3 of the conventional amount. . Further, as is clear from the actual measurement data shown in FIG. 6, even if the amount of the dispersant added is reduced to 1/2 by adding the hydrocolloid, the CWM having the almost same relationship between the coal concentration and the viscosity is produced. We were able to.

Therefore, the cost of the high-concentration coal / water mixed fuel can be reduced by reducing the dispersant cost by reducing the amount of the dispersant added while maintaining the fluidity of the CWM to be equal.

Since only the hydrocolloid is added, the existing high-concentration coal / water mixed fuel production facility can be used as it is, and it is almost unnecessary to add the facility.

Further, in the method for producing a high-concentration coal-water mixed fuel according to claim 6, since the hydrocolloid is added to the mixture of pulverized coal and water, and then the dispersant is added, the pulverized coal is added. By adding a hydrocolloid to a mixture of water and water and mixing, a gelled pulverized coal slurry is produced. By adding and mixing a dispersant to this slurry, the pulverized coal slurry becomes a sol. As a result, it is possible to manufacture a high-concentration coal / water mixed fuel in which the amount of the dispersant added is further reduced. For example, as is clear from the actual measurement data of FIG. 14, a high-concentration coal having the same fluidity as that of a conventional high-concentration coal-water mixed fuel in which a hydrocolloid is not added and a dispersant of, for example, 0.4 wt% is added. In order to obtain a water-mixed fuel, 1 ppm of hydrocolloid is added prior to the dispersant so that the addition amount of the dispersant is 1% of the conventional addition amount.
It can be reduced to / 2-1 / 4.

The amount of the hydrocolloid added is the same as the hydrophobic colloid.
Adsorbs to coal particles, which are id particles, to make the surface hydrophilic
A sufficient amount to exert a protective effect and as little as possible
The amount is preferably, and preferably high concentration as in claims 2 and 8.
The amount of water is less than 1 wt% of the coal / water mixed fuel
More than the amount that causes mutual coagulation with pulverized coal, more preferably
Is the water of high concentration coal-water mixed fuel as claimed in claims 3 and 9.
1 ppm or less 10 ^-FourAn amount greater than or equal to ppt (ie, p
10 from pm order^-Fourquantity in ppt order), most preferred
More preferably, high-concentration coal / water mixture as claimed in claims 4 and 10
Amount of fuel moisture below 1 ppb and above 1 ppt
The amount from the ppt order to the ppb order)
And Specifically, it is clear from the measured data in FIG.
Therefore, in order to obtain a CWM of 70% concentration,
The amount of colloid to be added from the ppt order to ppb
The highest concentration of coal with the highest fluidity
・ Water mixed fuel can be obtained.

Further, in the method for producing a high-concentration coal-water mixed fuel according to claim 7, the pulverized coal is finely pulverized by further grinding the pulverized coal obtained by dry pulverization so that the pulverized coal is pressed against each other and rubbed against each other. Since it is assumed that the corners of the charcoal are scraped and made spherical and ultrafine particles are generated,
Further, it is possible to produce high-concentration coal / water fuel having high fluidity and high concentration.

That is, since the pulverized coal is rounded and spherical to reduce the surface area, the amount of ultrafine particles required to fill the gaps between the pulverized coals is reduced. Moreover, since the easily shaving areas are scraped off, the main particles are spheroidized, but the initial particle diameter does not become extremely small, and ultrafine particles can be generated. On the other hand, the scraped corners become ultrafine particles, which are filled in the gaps between the pulverized coal particles. Therefore, a sufficient amount of ultrafine particles is filled in the gap between the pulverized coals. As a result, high-concentration coal
Wide particle size distribution required for the water-mixed fuel to gain fluidity,
That is, spheroidized relatively large particles to extremely fine particles can be easily generated by spheroidizing pulverized coal to adjust the particle size distribution suitable for high-concentration coal and water mixed fuel. Then, moisture is expelled from the gaps between the pulverized coals, and a high-concentration CWM or CWP can be obtained. Further, since the surface of the pulverized coal is adhered so that the ultrafine particles cover the pulverized coal to cause a lubricating effect, it is possible to obtain a CWM or CWP having high fluidity.

As shown in the actual measurement data of FIG. 15, the CWM with spherical shape (marked with ▲) is the CWM not marked with sphere (marked with Δ).
It is clear that it is more liquid than. Moreover, since it is not necessary to mix a large amount of ultrafine particles, the production of CWM or CWP can be simplified and the production cost can be reduced. Further, according to the present invention, since the crushing power is further reduced, the existing manufacturing equipment can be used as it is, and it is almost unnecessary to add the equipment.

[Brief description of drawings]

FIG. 1 is a principle view showing an example of a system for manufacturing a CWM according to the present invention.

FIG. 2 is a principle view showing an example of another system for manufacturing the CWM of the present invention.

FIG. 3 is a principle view showing an example of a system for manufacturing a CWP of the present invention.

FIG. 4 is a schematic perspective view showing an embodiment of a spheronizing device.

FIG. 5 is a schematic diagram showing a spheroidizing state of pulverized coal, (A)
Shows before spheroidization, and (B) shows after spheroidization.

FIG. 6 is a micrograph showing the particle structure of pulverized coal before spheroidization.

FIG. 7 is a micrograph showing a particle structure of pulverized coal spheroidized by a spheronizer.

FIG. 8 is a schematic perspective view showing a modified example of the embodiment of the spheroidizing device.

FIG. 9 is a schematic perspective view showing another embodiment of the spheroidizing device.

FIG. 10 is a schematic perspective view showing another embodiment of a spheronizing device.

FIG. 11 is a schematic perspective view showing still another embodiment of a spheroidizing device.

FIG. 12: Wet pulverized coal and CW in the production method of the present invention
It is a particle size distribution diagram (mass standard) of M.

FIG. 13 is a graph showing the relationship between the concentration of hydrocolloid added and the viscosity of CWM.

FIG. 14 is a graph showing the relationship between the amount of dispersant added and the viscosity of CWM.

FIG. 15 is a graph showing the relationship between CWM coal concentration and viscosity.

[Explanation of symbols]

 1 Coal 2 Pulverized coal 7 Hydrocolloid 9 Dispersant 10 CWM (High concentration coal / water mixed fuel)

Claims (10)

[Claims] 1. A high-concentration coal-water mixed fuel prepared by mixing pulverized coal obtained by pulverizing coal into a predetermined particle size distribution, water, and a dispersant, wherein a hydrocolloid that produces a protective effect on the pulverized coal is produced. A high-concentration coal-water mixed fuel characterized by containing. 2. The amount of the hydrocolloid is less than 1 wt% of the water content of the high-concentration coal-water mixed fuel, and is more than the amount that causes mutual coagulation with the pulverized coal. High-concentration coal / water mixed fuel described. 3. The high concentration coal / water mixed fuel according to claim 1, wherein the hydrocolloid is 1 ppm or less and 10 ⁻⁴ ppt or more of the water content of the high concentration coal / water mixed fuel. 4. The high-concentration coal / water mixed fuel according to claim 1, wherein the hydrocolloid is 1 ppb or less and 1 ppt or more of the water content of the high-concentration coal / water mixed fuel. 5. A method for producing a high-concentration coal / water mixed fuel by mixing pulverized coal obtained by pulverizing coal into a predetermined particle size distribution, water and a dispersant, and producing a protective effect on the pulverized coal. A method for producing a high-concentration coal / water mixed fuel, which comprises adding and mixing a hydrocolloid. 6. The method for producing a high-concentration coal-water mixed fuel according to claim 5, wherein the hydrocolloid is added to a mixture of the pulverized coal and the water, and then the dispersant is added. . 7. The pulverized coal is obtained by dry pulverization and further pulverized so that the pulverized coal is crushed by pressing and rubbing each other, whereby the pulverized coal is chamfered to have a spherical shape and ultrafine particles. It is what was produced | generated, The manufacturing method of the high concentration coal-water mixed fuel of Claim 5 or 6 characterized by the above-mentioned. 8. The amount of the hydrocolloid is less than 1 wt% of the water content of the high-concentration coal-water mixed fuel, and is more than the amount that causes mutual coagulation with the pulverized coal. A method for producing a high-concentration coal-water mixed fuel as described. 9. The method for producing a high-concentration coal / water mixed fuel according to claim 5, wherein the hydrocolloid is 1 ppm or less and 10 ⁻⁴ ppt or more of the water content of the high-concentration coal / water mixed fuel. 10. The method for producing a high-concentration coal / water mixed fuel according to claim 5, wherein the hydrocolloid is 1 ppb or less and 1 ppt or more of the water content of the high-concentration coal / water mixed fuel.