JPS6270490A - Production of high-concentration coal-water slurry - Google Patents

Abstract

PURPOSE:To obtain the titled slurry having excellent combustibility and storage stability with small pulverizing power, by feeding coal, water and dispersant in a wet pulverizer and pulverizing the mixture, removing coarse particles from the pulverization product with a classifier, and mixing the pulverization product with a stabilizer in a mixer. CONSTITUTION:Raw coal is fed into a coarse pulverizer 1, to be coarsely pulverized therein and fed into a wet pulverizer 2 together with water and a dispersant (e.g., salt of sulfate of a higher alcohol) to pulverize the mixture. Coarse particles are removed from the pulverization product with a classifier 3. The pulverization product is then fed into a mixer 4. A stabilizer (e.g., alkali metal salt of carboxymethylcellulose) is fed into the mixer and mixed with the pulverization product through stirring to obtain an intended high-concn. coal-water slurry. In the above process, the stabilizer is not fed into the wet pulverizer 2 together with the dispersant but is added after treatment with the classifier 3. This reduces the pulverization power as well as enables easy separation of coarse particles in the classifier 3, thus leading to reduction in the coarse particle contact of the slurry product.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to a water slurry (hereinafter referred to as This relates to a method for producing highly concentrated coal/water slurry.

[Conventional technology]

In recent years, due to the instability of oil supplies, technological development has been underway to effectively utilize carbonaceous solids such as coal, oil coke, and petroleum pitch. For example, various techniques for effectively utilizing these carbonaceous solids include pyrolysis, gasification, combustion, alternative fuels for blast furnace-injected heavy oil in the steel industry, and alternative fuels for heavy oil in cement giraffes. However, in these various utilization technologies, carbonaceous solids are difficult to handle because they are solid at room temperature.
It has disadvantages such as the risk of pollution caused by dust R dispersion and the risk of dust explosion, making it difficult to use.

Therefore, it is desirable to convert these carbonaceous solids into fluids to facilitate handling and prevent pollution and danger. On the other hand, in order to reduce the transport boost of carbonaceous solids, it is effective to transport them in the form of a fluid.

For the purpose mentioned above, it is effective to make a slurry as a method of fluidizing carbonaceous solids, but this slurry can be thermally decomposed, gasified, combusted, or blown into a blast furnace.
In order to use the slurry as a fuel for cement giraffes, it is necessary to make the slurry highly concentrated and to prevent solid particles suspended in the slurry from settling and causing solid-liquid separation.

Conventionally, coal, water, dispersant, and stabilizer are fed into a wet pulverizer and then ground and mixed to obtain a stable slurry, or coarse particles are removed by a classifier and then returned to the wet pulverizer inlet. etc. are known.

For example, as shown in FIG. 5, raw coal is introduced into a coarse pulverizer 1 and coarsely pulverized, and then introduced into a wet pulverizer 2 together with water, a dispersant, and a stabilizer to be finely pulverized. The slurry discharged from is introduced into the classifier 6 to remove coarse particles,
A method is known in which this slurry containing coarse particles is returned to the inlet of the wet grinder 2.

[Problem that the invention seeks to solve]

However, in all of the above-mentioned conventional techniques, a dispersant and a stabilizer are added at the same time. Adding stabilizers to slurry usually increases the viscosity, which increases the grinding power and makes it difficult to separate coarse particles in a classifier, increasing the coarse particle content of the product slurry and increasing flammability. Also, there arises a problem of poor storage stability.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a method for producing a highly concentrated coal/water slurry having excellent combustibility and storage stability.

[Means and effects for solving the problem] No. 1 of the present application
The method for producing a highly concentrated coal/water slurry according to the invention includes coal,
In the method of producing a highly concentrated coal/water slurry by mixing water, a dispersant, and a stabilizer, coal is introduced into a wet pulverizer together with water and a dispersant to be finely pulverized, and then introduced into a classifier to coarsely grind the coal. After removing the grains, a stabilizer is added and mixed using a mixer.

Further, the method for producing a highly concentrated coal/water slurry according to the second invention of the present application includes dry pulverizing a part of the raw material coal, separating it into fine powder and fine powder using a classifier, and coarsely pulverizing the remainder of the raw material coal. This coarsely pulverized coal and the fine powder are introduced into a wet pulverizer together with water and a dispersant to be finely pulverized, then introduced into a classifier to remove coarse particles, and then introduced into a mixer together with the fine powder and stabilized by a stabilizing agent. It is characterized by adding and stirring to mix.

A detailed description will be given below based on the drawings. FIG. 1 is a flow sheet showing an example of the first invention of the present application. Raw coal is first introduced into a coarse pulverizer 1 and coarsely pulverized, then the coarsely pulverized coal is introduced into a wet pulverizer 2 together with water and a dispersant and pulverized, and the slurry discharged from the wet pulverizer 2 is passed through a classifier. After introducing the slurry into B and removing coarse particles, a stabilizer is added and mixed with stirring in the mixer 4 to obtain a water slurry with excellent combustibility and storage stability. The coarse particle-containing slurry separated by the classifier 6 is circulated to the inlet of the wet crusher 2.

Further, FIG. 2 shows an example of the second invention.

In FIG. 2, a part of raw coal is introduced into a dry pulverizer 5 to be dry pulverized, and a classifier 6 separates it into fine powder and fine powder (for example, 150 μm or less). On the other hand, the remainder of the raw coal is introduced into the coarse pulverizer 1 and coarsely pulverized, and the coarsely pulverized coal and fine powder from the classifier 6 are introduced together with water and a dispersant into the wet pulverizer 2 and pulverized. After introducing it into the classifier B to remove coarse particles, it is introduced into the mixer 4 along with the fine powder from the classifier 6, and a stabilizer is added and mixed with stirring, resulting in a water slurry with excellent combustibility and storage stability. get. The coarse particle-containing slurry separated by the classifier 6 is circulated to the inlet of the wet crusher 2.

As the dispersant used in the present invention, anionic, cationic, nonionic surfactants, etc. may be used alone or in combination, and are appropriately selected depending on the type of coal. Specifically, anionic surfactants include fatty oil sulfate ester salts, higher alcohol sulfate ester salts, nonionic ether sulfate ester salts, olefin sulfate ester salts, alkylaryl sulfonates, and dibasic acid ester sulfonates. , dialkyl sulfosuccinate, acyl sarcosinate, alkylbenzene sulfonate, alkyl sulfate ester salt, polyoxyethylene alkyl (alkylphenol) sulfate Nisder salt, alkyl phosphate ester salt, dialkyl sulfosuccinate ester salt, acrylic acid or/and Maleic anhydride copolymers, polycyclic aromatic sulfonates, formalin compounds, etc. are used, cationic surfactants include argylamine salts, quaternary amine salts, etc., and nonionic surfactants include , polyoxyalkyl ether, polyoxyethylene argylphenol ether, oxyethylene oxypropylene block polymer, polyoxyethylene alkylamine, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, alkyltrimethylammonium chloride, alkyldimethylbenzyl Ammonium chloride, alkylpyridinium salts, polyoxyethylene fatty acid esters, fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, polyhydric alcohol fatty acid esters, fatty acid ethanolamides, etc. are used, and as amphoteric surfactants, Alkyl betaines, etc. are used, and amine compounds such as 1, 2, 3 monoamines and diamines, higher alkyl amino acids, etc. are used, and preferably sulfur and lithium naphthalene sulfonates, their formalin condensates, and dicyclopentadiene are used. A copolymer of a sodium salt of a sulfonate and sodium acetate is used, and the
It is added in an amount of 0.05 to 1.5% by weight, preferably 0.05 to 1.5% by weight.

In addition, the stabilizers used in the present invention include alkali metal salts of carboxymethyl cellulose (OMC),
bitroxyethyl cellulose (HKO), alkali metal salts of polyacrylic acid, polyvinyl alcohol, starch, karaya gum, mixture of karaya gum and polyacrylamide, polysaccharides modified with polyacrylates, alkali metal salts of alginic acid, bentonite, gum arabic, guar gum, Locust bean gum, tragacanth gum, British gum, Senegalese gum, crystal gano＼
Gums such as are used, and 0.0% to carbonaceous solid.
0001 to 5.0% by weight, preferably 0.001 to 1.0% by weight.
5% by weight is added.

〔Example〕

Examples and comparative examples are given below.

Example 1 A wet ball mill with an inner diameter of 480 m and a length of 960 m was used as a wet crusher, and a vibrating sieve equipped with a wire mesh with an opening of 500 μm was used as a classifier. A highly concentrated coal/water slurry with a slurry concentration of 66% and a 200-mesh passing rate of 80% was produced using this as a raw material. As a dispersant, 0.8% by weight of naphthalene sulfonic acid formamide condensate (IJium salt) was added per coal, and as a stabilizer, 0.8% by weight of carboxymethylcellulose sodium salt was added per coal. [
]05% by weight was added. The results were as shown in Table 1 and Figure 3.

Comparative Example 1 Using the same wet crusher as in Example 1, and using a vibrating sieve equipped with a wire mesh with an opening of 500 μm as a classifier,
A highly concentrated coal/water slurry having the same concentration and particle size as in Example 1 was produced according to the flow shown in FIG. The types and addition rates of raw coal, dispersant, and stabilizer were the same as in Example 1. The results were as shown in Table 1 and Figure 3.

Table 1 The slurry viscosity in Table 1 is the value measured using a Saleh rheometer at a sliding speed of 1005 ec and 1.25° C. on the descending curve of the flow curve of the slurry.

From Table 1 and Figure 5, according to the method of the present invention, the power consumption rate is reduced by about 9% compared to the conventional method, the coarse particle content of the product slurry is reduced, and the combustibility and storage stability are improved. It can be seen that a highly concentrated coal/water slurry with excellent properties was obtained.

Example 2 A wet ball mill with an inner diameter of 489 u and a length of 9601% was used as a wet crusher bowl, and a vibrating sieve equipped with a wire mesh with an opening of 500 μm was used as a classifier. Using coal as a raw material, a highly concentrated coal/water slurry with a slurry concentration of 66% and a 200-mesh passing rate of 80% was produced. As a dispersant, 0.8% by weight of naphthalene sulfonic acid formamide condensate (IJium salt) is added per coal, and as a stabilizer, 0.8% by weight of carboxymethylcellulose sodium salt is added per coal.
0.005% by weight was added. In addition, pulverized coal is less than 1508m1
The slurry concentration at the outlet of the wet pulverizer was 60%.

The results were as shown in Table 2 and Figure 4.

Comparative Example 2 Using the same wet crusher as in Example 2, and using a vibrating sieve equipped with a wire mesh with an opening of 500/1 m as a classifier, the same concentration and particle size as in Example 2 was prepared according to the flow shown in Figure 6. A highly concentrated coal/water slurry was produced. The types and addition rates of raw coal, dispersant, and stabilizer were the same as in Example 1. The results were as shown in Table 2 and Figure 4.

Note that the slurry viscosity in Table 2 is the same measured value as in Table 1.

From Table 2 and Figure 4, it can be seen that according to the method of the present invention, the power consumption rate is reduced by about 6% compared to the conventional method, the coarse particle content of the product slurry is reduced, and the combustibility and storage stability are improved. It can be seen that a highly concentrated coal/water slurry with excellent properties was obtained.

〔Effect of the invention〕

As explained above, in the method of the present invention, the stabilizing agent is not introduced into the wet crusher at the same time as the dispersant, but is added downstream of the classifier, so the crushing power is smaller and more economical than in the conventional method. and it is easy to separate coarse particles with a classifier,
That is, the classification diameter can be reduced, the coarse particle content of the product slurry can be reduced, and a highly concentrated coal/water slurry with excellent combustibility and storage stability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing an example of the first invention of the present application;
FIG. 2 is a flow sheet showing an example of the second invention, FIG. 5 is a particle size distribution diagram of slurry in Example 1 and Comparative Example 1, and FIG. 4 is a particle size distribution diagram of slurry in Example 2 and Comparative Example 2. , FIG. 5 is a flow sheet showing the conventional method, and FIG. 6 is a flow sheet for Comparative Example 2.

Claims (1)

[Claims] 1. A method for producing a highly concentrated coal/water slurry by mixing coal, water, a dispersant, and a stabilizer, in which coal is introduced into a wet pulverizer together with water and a dispersant and pulverized. A method for producing a highly concentrated coal/water slurry, which is characterized in that the slurry is then introduced into a classifier to remove coarse particles, a stabilizer is added, and the slurry is stirred and mixed in a mixer. 2. In a method of producing a highly concentrated coal/water slurry by mixing coal, water, a dispersant, and a stabilizer, a portion of the raw material coal is dry-pulverized, separated into fine powder and fine powder by a classifier, and the raw material The remainder of the coal is coarsely pulverized, and the coarsely pulverized coal and the fine powder are introduced into a wet pulverizer together with water and a dispersant to be finely pulverized, and then introduced into a classifier to remove coarse particles, and then mixed with the fine powder. A method for producing a highly concentrated coal/water slurry, which is characterized by introducing the slurry into a mixer, adding a stabilizer, and stirring and mixing.