JP2678726B2 - Production method of high concentration coal / water slurry - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is how to produce a high concentration coal-water slurry suitable for use as a fuel, by details, reduced calorie up and additive addition rate due to the increase in coal concentration value It relates to the production how a high concentration coal-water slurry which can reduce costs.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a high-concentration coal / water slurry, for example, as disclosed in Japanese Patent Publication No. 61-49356, coal and water are added to a slurry discharged from a first-stage wet pulverizer. Alternatively, a method is known in which coal, water and a dispersant are added and introduced into a second stage wet pulverizer to adjust the particle size of the coal.

Further, Japanese Patent Laid-Open No. 60-8393 discloses that
In a method for producing a coal / water slurry by wet-milling coal, the coal is first pulverized in the presence of a high concentration of coal, and then water is added to the obtained high concentration of the coal / water slurry to reduce the amount of coal. A method of forming a thickened coal / water slurry is described.

Japanese Patent Publication No. 2-54397 discloses that
The ball mill is divided by a porous partition plate so that the diameter of the balls stored in each chamber gradually changes from the first chamber on the mill inlet side to a small one, and coal, water and a dispersant are added to the first chamber of the ball mill. Of the above, and a method of pulverizing by supplying the remaining amount of the dispersant to at least one chamber after the second chamber.

Further, in Japanese Patent Application Laid-Open No. 60-58491, the yield value of the slurry is raised by stirring the coal / water slurry to give a shearing force, so that the yield value is 0.1 to 20 dyne / Stabilization methods are described that adjust to be in the cm ² .

[0006]

The methods described in the above publications do not satisfy both the requirements of significantly lowering the viscosity of the slurry and increasing the ultimate concentration, and
The addition rate of the additive cannot be reduced. It should be noted that the above publication does not disclose any technical idea of adding water and additives to a wet-milled coal / water slurry and kneading the mixture. In order to solve the above-mentioned problems, the present inventors have conducted various experiments and researches, and as a result, added kneading treatment after adding water or water and an additive to the slurry discharged from the wet pulverizer. It has been found that by carrying out the method, the viscosity of the product slurry can be significantly reduced, the ultimate concentration can be increased, and the addition rate of the additive can be reduced.

The present invention has been made based on the above findings, and an object of the present invention is to increase the calorie by increasing the coal concentration value and reduce the cost by decreasing the additive addition rate in the production of high-concentration coal / water slurry. is to provide a manufacturing how a high concentration coal-water slurry which can be achieved. The "reaching concentration" means the coal concentration when the coal / water slurry has a typical viscosity of 10 poise.

[0008]

In order to achieve the above object, in the method for producing a high-concentration coal / water slurry of the present invention, wet pulverization was performed at a concentration higher than the target product slurry concentration in advance. After that, water and additives are added to the slurry discharged from the wet pulverizer, and the mixture is kneaded to adjust the coal concentration to the target product slurry concentration, thereby lowering the slurry viscosity and increasing the reached concentration. Moreover, the additive addition rate is suppressed. Usually the additives are
In order to stabilize the slurry property variation during wet pulverization, the additive aqueous solution is added in an amount slightly above the minimum addition rate, but in the method of the present invention, the excess additive aqueous solution is wet pulverized and then discharged from the wet pulverizer. By adding to the prepared slurry, the ultimate concentration can be increased and the addition rate can be reduced.

Next, the structure of an apparatus for carrying out the method of the present invention will be described with reference to the drawings. The apparatus for carrying out the method of the present invention comprises, as shown in FIGS. 2 and 3 , a wet crusher 12 for wet crushing coal, water and additives to prepare a coal / water slurry. The kneader 16 is connected to the wet crusher 12 and performs a kneading process by adding water and additives to the coal / water slurry. In addition, in FIG. 1, only water is added to the kneading machine 16.
Add to adjust coal concentration to target product slurry concentration
At the same time, it lowers the slurry viscosity and raises the final concentration.
In the method of the present invention, a kneading treatment is shown.
By adding water and additives in the process,
It is possible to reduce the viscosity of the slurry and increase the reached concentration.
Wear. In addition, it is possible to further reduce the addition rate of additives.
it can.

The apparatus for carrying out the method of the present invention may be constructed by adding the coarse crusher 10 and the coarse particle classifier 14 to the above apparatus. That is, in this case, the
As shown in FIGS. 2 and 3 , the apparatus for carrying out the method includes a coarse crusher 10 for coarsely crushing coal, and a coarse crusher 10 connected to the coarse crusher 10 for wet crushing coarsely crushed coal, water and additives. coal·
Wet pulverizer 12 for preparing water slurry, coarse grain classifier 14 connected to this wet pulverizer 12, and coarse grain classifier 14 are connected to coal / water slurry by adding water and additives. The kneading machine 16 performs a kneading process.

A hammer crusher or the like is used as the coarse crusher 10, a wet ball mill, a wet rod mill or the like is used as the wet crusher 12, and an auto strainer, a vibrating screen or the like is used as the coarse particle classifier 14, and kneading is performed. As the machine 16, a line mixer, a vertical mixer, a horizontal mixer, or the like is used.

The additive is preferably supplied as an aqueous solution of the additive, but it is also possible to supply the additive and water separately. Although FIG. 1 shows the case where only water is supplied to the kneading treatment step, this water may be added directly to the kneader 16 or may be added to the slurry entering the kneader 16. FIG. 2 shows a case where an additive aqueous solution is added to the kneading step, and FIG. 3 shows a case where an additive aqueous solution and water are added to the kneading step. Also in this case, the additive aqueous solution,
Alternatively, the aqueous additive solution and water may be added directly to the kneader 16 or may be added to the slurry entering the kneader 16. Further, instead of the aqueous additive solution, the additive and water may be separately supplied.

Using the apparatus shown in FIG . 1, high-concentration coal / water
The process of manufacturing a rally is as follows (a),
(B) That is, (a) a step of wet-milling coal, water and an additive to prepare a coal / water slurry, and (b) a step of adding water to the coal / water slurry and kneading the mixture. ing. In this case, when water is added to the coal / water slurry from the wet crushing step, the concentration decrease due to water addition is in the range of 0.20 to 3.0% by weight, preferably 0.5 to 1.5% by weight. It is preferable. When the concentration decrease is less than 0.20% by weight, there is an inconvenience that the effect of decreasing the viscosity of the slurry and the effect of reducing the addition rate of the additive are hardly seen, while when it exceeds 3.0% by weight, wet grinding is performed. Since the coal concentration and viscosity at that time become high, there is a disadvantage that the power required for crushing increases significantly.

In order to achieve the above-mentioned object , the present invention
As shown in FIGS. 2 and 3, the method for producing a high-concentration coal / water slurry is as follows: (a) a step of wet pulverizing coal, water, and an additive to prepare a coal / water slurry; A process of adding water and additives to a water slurry and kneading the mixture. In the method of the present invention, as described above, it is preferable to add at least a part of water and the additive as an additive aqueous solution.

In the method of the present invention, the concentration of the additive aqueous solution is 2.0 to 50% by weight, preferably 5.0 to 30.
It is preferable to set the weight%. If it is less than 2.0% by weight, the amount of water added together with the additive becomes too large,
On the other hand, there is a disadvantage that the slurry concentration is too low. On the other hand, when it exceeds 50% by weight, the viscosity of the aqueous additive solution becomes too high, which makes it difficult to supply the additive.

Further, the weight ratio of the additive addition ratio before and after the wet pulverization step is preferably front: back = 20: 1 to 1: 1 and more preferably 10: 1 to 2: 1. 2
If it exceeds 0: 1, the effect of lowering the viscosity due to divided addition,
There is an inconvenience that the effect of reducing the additive addition ratio is hardly seen. On the other hand, when it is less than 1: 1, the amount of the additive added during the wet pulverization becomes too small, and the slurry viscosity in the pulverizer increases, As a result, there is an inconvenience that the power required for pulverization is significantly increased.

As shown in FIGS. 2 and 3, coarse crushed coal from the coarse crusher 10 is used as the coal, or coarse coal in the coal / water slurry is used between the wet pulverization step and the kneading treatment step. It is preferable to provide a classification step for separating the particles. The coarse particles separated by the coarse particle classifier 14 are 0.3 to 2 m.
It is preferable that it is m. In actual operation, it is set to 0.8 mm or more as an example. As the additive, a dispersant, a stabilizer, or both are used.

As the dispersant, sodium lignin sulfonate, formalin condensate of sodium naphthalene sulfonate, sodium polystyrene sulfonate, sodium poly (meth) acrylate, sodium polyisoprene sulfonate, polyethylene glycol nonylphenyl ether formalin condensate are used. Preference is given to using. Among the above dispersants, polyethylene glycol nonylphenyl ether formalin condensate is a nonionic type,
Others are anionic.

Bentonite, carboxymethyl cellulose (CMC), polysaccharides (polysaccharides such as xanthan gum and guar gum), attapulgite clay and goethite are preferably used as the stabilizer.

[0020]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention may be practiced by appropriately changing the gist of the invention. Is possible. Test Example 1 This test example is based on the two-stage water addition method shown in FIG. First, the test coal having the properties shown in Table 1 was crushed with a hammer crusher to a grain size of 3 mm or less and 90% to obtain coarsely crushed carbon.

[0021]

[Table 1]

Then, coarse pulverized coal, water, and an aqueous dispersant solution (20% by weight sodium polystyrene sulfonate solution) were introduced into a wet ball mill so that a predetermined coal concentration and a predetermined dispersant addition rate were obtained, and a coal particle size of 200 mesh pass was applied.
After crushing to 80-82%, the slurry was discharged from the ball mill. A high concentration coal / slurry was prepared by adding water to the discharged slurry in an amount such that the concentration becomes 1% by weight, and then kneading the mixture through a line mixer. The results are shown in Table 2.

[0023]

[Table 2]

Example 1 This example is based on the two-stage addition method of the additive (dispersant in this case) shown in FIG.
First, the test coal having the properties shown in Table 1 was crushed with a hammer crusher to a grain size of 3 mm or less and 90% to obtain coarsely crushed carbon. Then, coarse pulverized coal, water, and a dispersant aqueous solution (20% by weight sodium polystyrene sulfonate aqueous solution) were introduced into a wet ball mill so that a predetermined coal concentration and a predetermined dispersant addition rate were obtained, and a particle size of 200 mesh pass 80 to 82 was obtained.
After crushing to 100%, the slurry was discharged from the ball mill. A predetermined amount of a dispersant aqueous solution (sodium polystyrene sulfonate 20% by weight aqueous solution) was added to the discharged slurry to adjust the coal concentration, and the mixture was kneaded through a line mixer to prepare a high-concentration coal / water slurry.
The results are shown in Table 3.

[0025]

[Table 3]

COMPARATIVE EXAMPLE 1 (Conventional method) Sample coal having the properties shown in Table 1 was used for 3 times with a hammer crusher.
It was crushed to a grain size of 90% or less and 90% to obtain coarsely crushed carbon. Then, coarse crushed coal, water, and a dispersant aqueous solution (20% by weight sodium polystyrene sulfonate aqueous solution) were introduced into a wet ball mill so that a predetermined coal concentration and a predetermined dispersant addition rate were obtained, and a coal particle size of 200 mesh pass 80 to 82% was obtained. After crushing, it was discharged from the ball mill. The discharged slurry was passed through a line mixer and kneaded to prepare a high-concentration coal / water slurry. The results are shown in Table 4.

[0027]

[Table 4]

The coal concentration in Test Example 1, was prepared by the method shown in Example 1, the ratio Comparative Examples 1 slurry, dispersant additive ratio, shown typical viscosity values in Tables 2, 3 and 4. Further, based on these values, the relationship between the coal concentration and the representative viscosity is shown in FIG. 4, and the relationship between the dispersant addition rate and the ultimate concentration is shown in FIG.
In addition, FIG. 4 shows a dispersant addition rate: 0.50 wt% vsC
(Wt% relative to the weight of coal in the coal / water slurry), trial
Density reduction by two-stage addition of water in our case 1: 1 wt
%, Dispersant Addition Ratio in Example 1 Before: After = 4: 1
Is the case. Further, FIG. 5 shows the case where the concentration decrease due to the two-stage addition of water in Test Example 1 is 1 wt%, and the dispersant addition ratio ratio in Example 1 is front: back = 4: 1.

The "representative viscosity" is defined as follows. Coal / water slurry viscosity is 25 ° C, using a rotational viscometer, the shear rate by the rotor is 0-150s
It is measured while gradually increasing to ec ⁻¹ , and then 15
The measurement is made while gradually decreasing from ⁰ to 0 sec ^-1, and the shear rate is 100 when the shear rate is reduced.
The apparent viscosity at sec ⁻¹ is defined as the representative viscosity.

From FIG. 4, the conventional method (Comparative Example 1), Test Example 1
In the two-stage addition kneading method of water shown in Fig. 1 and the two-stage addition kneading method of the dispersant shown in Example 1 , the concentration values reaching the representative viscosities are 68.3, 70.8 and 72.0 wt%, respectively. Law (Comparative example 1) two-step addition-kneading method of water compared to the (test example
In the case of 1) , it increased by about 2.5 wt%, and in the case of the two-stage addition and kneading method of the dispersant (Example 1) , it further increased by about 3.7 wt%. On the other hand, from FIG. 5, the required dispersant addition rate to the ultimate concentration of 69 wt% is 0.7 wt% in the conventional method (Comparative Example 1) , while it is approximately 0 in the two-stage water addition method (Test Example 1). .32
It can be seen that in the case of the two-step addition method of the dispersant (Example 1) , it is further reduced to 0.27 wt%.

[0031]

As described above, the present invention has the following effects. (1) coal, water and additives in a high concentration coal-water slurry obtained by wet grinding, by the addition of water and additives to kneading treatment to further greatly reduce the viscosity of the slurry, reaching It is possible to increase the concentration and reduce the addition rate of the additive. (2) Since the coal / water slurry concentration value obtained by the kneading process is increased, calories can be increased as a fuel, and the cost can be reduced by reducing the additive addition rate.

[Brief description of the drawings]

[1] One apparatus for carrying out the method of producing a high concentration coal-water slurry to be added is only water in the kneading step
It is a block diagram showing an example .

FIG. 2 shows a method for producing a high-concentration coal / water slurry according to the present invention.
FIG. 3 is a block diagram showing a second embodiment of an apparatus to be implemented.

FIG. 3 is a block diagram showing another embodiment of the device of the present invention.

FIG. 4 is a graph showing the relationship between coal concentration and representative viscosity.

FIG. 5 is a graph showing the relationship between the dispersant addition rate and the ultimate concentration.

[Explanation of symbols]

 10 Coarse crusher 12 Wet crusher 14 Coarse grain classifier 16 Kneader

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshitaka Imori 1-1 Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi Plant (72) Hironori Ozaki 1780 Uetakano, Yachiyo-shi, Chiba Shigeru Kawasaki Industry Co., Ltd. Yachiyo Factory (56) References JP-A-4-372691 (JP, A) JP-A-60-8393 (JP, A)

Claims (7)

(57) [Claims] 1. A step of (a) wet-milling coal, water and an additive to prepare a coal / water slurry, and (b) a step of adding water and an additive to the coal / water slurry and kneading the mixture. A method for producing a high-concentration coal / water slurry, which comprises: Wherein at least a portion and additives that be added as an additive solution 請 Motomeko 1 method for producing a high concentration coal-water slurry according water. 3. The concentration of the additive aqueous solution is 2.0 to 50% by weight.
Der Ru請 Motomeko 2 high concentration method for producing a coal-water slurry according. Wherein the weight ratio of the additive addition rate that is added before and after the wet grinding process, prior: rear = 20: 1 to 1: 1 der Ru請 <br/> Motomeko 1, 2 or 3, wherein High-concentration coal / water slurry manufacturing method. 5. A method for producing a high concentration coal-water slurry according to any one coal is coarsely pulverized coal der Ru請 Motomeko 1-4. 6. Between the wet pulverization step and the kneading treatment step,
Provided classification step of separating coarse coal-water slurry
Method of producing a high concentration coal-water slurry according to any one of 請 Motomeko 1-5. As 7. additive, dispersant or stabilizer, or method of producing a high concentration coal-water slurry according to any one of 請 Motomeko 1-6 Ru with both.