KR910009382B1 - Aqueous slurry of solid fuel and a process for the production thereof - Google Patents

Abstract

A coal/water mixed fuel is composed of 0.1-1 wt.% naphthalene sulfonic formaldehyde condensate ammonium salt as a dispersing agent (A), 0.1-1 wt.% ammonia water as a pH controlling agent (B), 1- 5 wt.% ash, 60-70 wt.% pulverized coal and the residual water. The producing method comprises crude-grinding the coal, floating it, fine-grinding it, adding the agent (A) and the agent (B) to it, and homogenizing the mixture.

Description

Low ash coal-water mixed fuel and continuous production method thereof

1 is a schematic manufacturing process diagram of a mixed fuel according to the present invention.

The present invention relates to a low ash coal-water mixed fuel and a continuous production method thereof. The present invention relates to advantages such as ease of transportation and combustion, and a large amount of ash (ASH) contained in coal, compared to coal slurization in the prior art. And a low ash coal-water mixed fuel having a further advantage such as eliminating sulfur powder (SULFUR) and eliminating environmental problems and direct combustion into a modified oil boiler, and a continuous production method thereof.

Various methods of producing coal-water mixed fuels are already known.

Italy, in particular, No. 21885A, 20261A (Korean Patent No. 20837), relates to a water-soluble coal suspension prepared by pulverizing coal into two groups of different sizes and mixing a polymer electrolyte and a stabilizer. Disadvantages of crushing into two groups of different sizes and adding a dispersant after pulverization have low grinding effect and high grinding cost. As a suspension without ashing process, it is possible to burn directly in oil boiler due to ash disturbance. The problem is that excessive sulfur dioxide that is not removed causes excessive sulfurous acid gas (SOx) in combustion, which causes pollution problems. The same stability can be achieved by injecting the polymer electrolyte and stabilizer together. There is a disadvantage that the manufacturing cost is more expensive than the present invention.

Thus, the present inventors have conducted a number of experiments and studies, and as a result, coarse grinding is divided into fine grinding, and a series of processes are introduced by inserting a tanning process between the coarse grinding and fine grinding, thereby providing a significant amount of ash and sulfur powder. In order to complete the present invention, the present invention can be solved significantly by solving the above-mentioned disadvantages of the conventional water-soluble suspension suspension by removing the, and injecting the dispersing agent and the PH adjusting agent in the fine grinding process and modifying the dispersing agent of the existing process. It became.

Accordingly, an object of the present invention is to provide an improved low ash coal-water mixed fuel containing low ash pulverized coal and a known dispersant, which can solve the problems of the conventional water-soluble coal suspension. The present invention provides a method for continuously producing low ash coal-water mixed fuel.

Low ash coal-water mixed fuel according to the present invention is a dispersant, containing 0.1 to 1% by weight of naphthalenesulfonic acid formalin condensate ammonium salt having a molecular weight of at least 3000 or more, and 0.1 to 1% by weight of ammonia water. On the basis of coal, 1 to 5% by weight of ash and at least 80% contain pulverized coal having a particle size distribution of -200 mesh to 65 to 75% by weight of the total fuel and the remainder consists of water.

Preferably, as the dispersant, a monovalent anion salt having a molecular weight of 6,000 to 10,000 is preferable, and even more preferably, a compound known under the trademark of Highcoal N250AS of Dai-Ichi Kogyo Seiyaku of Japan has a molecular weight of about 8,000. much better.

The amount of dispersant in the fuel is preferably 0.3 to 0.5% by weight, in particular 0.4% by weight, on a coal basis.

Method for producing a low ash coal-water mixed fuel according to the present invention,

(A) Process of pulverizing so that at least 98% of coal is -50 mesh or less (ball mill No. 1)

(B) Coking process to make ash content 1 to 5% by weight based on coal

(C) A process of pulverizing (ball mill NO.2) so that at least 80% of coal is -200 mesh, and simultaneously injecting dispersant and PH modifier.

(D) It consists of a high speed agitation process for homogenizing the low ash coal-water mixed fuel produced.

In addition, the manufacturing method of the present invention may include a magnetic separator to remove impurities such as iron after each grinding process.

The flotation process of (b) is suitable for the Float Flotation process, which generates a large number of fine bubbles in the mineral liquid suspended in the crushed ore particulates, and the rising bubbles are hydrophobic minerals on the surface. Is a buoyancy of bubbles, which is suspended to the surface of water (in the form of group of mineralized bubbles), and is a method of recovering mineral particles, which have a large relationship with the particle size. The smaller the particle size, the higher the ash removal rate and the coal recovery rate. If the particle size is too small for the production of water mixed fuel, the coal concentration cannot be increased, so it can only be crushed to a certain particle size, and considering the possibility of adjusting the particle size distribution of the final product, the particle size of the coarse grinding process is 98%- It should be no more than 50 mesh, and the particle size of the pulverization process is at least 80% -200 mesh to achieve the desired effect of the present invention.

In addition, by injecting the dispersant and ammonia water in the fine grinding process, it prevents the aggregation phenomenon between the particles to be pulverized and smooth the flow in the pulverizer to improve the crushing efficiency and reduce the power cost for the crushing.

In this case, the dispersant to be injected may include a monovalent anion of naphthalenesulfonic acid. In the known prior art, dispersants have a molecular weight of about 2,000 to obtain only a dispersing force due to electrical repulsive force between particles. On the contrary, in the present invention, various dispersants having a molecular weight of 3,000 to 10,000 are used. The dispersant having a high molecular weight is not only an electrical repulsive force between particles, but also a steric effect (the effect of a nonionic surfactant) It does not require the addition of stabilizer by igniting the dispersing force by Steric Effect and fundamentally preventing the aggregation phenomenon between particles.

In addition, the PH modifier was added to neutralize the acidic product in this process, thereby increasing the dispersing effect by removing polyvalent cations (iron ions, calcium ions) by precipitation. COOH), the carboxyl group is negatively charged to increase the dispersion effect.

Low ash coal-water mixed fuel according to the present invention has a viscosity of 800 ~ 1,300P (88 Sec ^-1 , Haake Viscometer RV II) and a stability of 1 month or more, unlike the Italian Patent No. 21885A, 20261A Injecting dispersant and ammonia water in the oil boiler can be directly modified and applied directly, and it is not necessary to inject other expensive stabilizers by injecting a high molecular weight known dispersant and ammonia water. I can do it.

In addition, the final product may be homogenized by introducing a high-speed stirring process in the final step, and in some cases, a pulverized iron powder may be removed by installing a magnetic separator after each grinding process to improve the quality of the final product. There is a number.

Hereinafter, the specific manufacturing method and its effect of the present invention through the test and examples will be described. However, the following tests and examples do not limit the scope of the present invention.

1. The characteristics of the coal tested in the present invention are shown in Table 1.

TABLE 1

2. The coal experiments were conducted for each of the coals used in the present invention, and the results are shown in Table 2 below.

TABLE 2

3. The dispersant was injected as described in Table 3 below. As a result, the fuel was measured by Haake Viscometer RV II, 88 Sec _-1 (the lower the better), and 1% of the low ash coal-water mixed fuel settled down to a hard form. The time taken to solidify was measured and the results are shown in Table 3.

TABLE 3

4. The dispersant and ammonia injection effects were tested in the grinding process and the results are shown in Table 4.

TABLE 4

5. The stability effect by the high speed agitation was tested and the results are shown in Table 5 below.

TABLE 5

EXAMPLE

The coal mill A of Table 1 having a particle size of 6 mm or less and 100% or less of ash content of 8.67 wt% based on coal is injected into 3.248T / H at the ball mill No.1 input of FIG. After that, the ash content was reduced to 4.50% by weight based on coal, and then injected into the vacuum filter at 3.051T / H, and the coal concentration increased from 7.5% to 75% by weight in a ball mill at 3.279T / H. Inject No.2 at 3.032T / H and at the same time disperse Highcoal N 250AS with a molecular weight of 8,000 and ammonia water at 32.48Kg / H and 25.47Kg / H, respectively. %, A low ash coal-water mixed fuel having a viscosity of 1,028 CP was prepared and injected into a high-speed stirrer at 3.032T / H, and the coal concentration was 64.1% by weight and the ash content was 4.50% by weight based on coal. Low ash coal / water mixture with 933CP and 25 days of stability with particle size of 200 mesh or less and 81.5% Fuel was prepared.

Claims (11)

It contains 0.1 to 1% by weight of naphthalene sulfonic acid formalin condensate ammonium salt having a molecular weight of 3,000 to 10,000 as a dispersant, 0.1 to 1% by weight of ammonia water, and 1 to 5% by weight of ash based on coal. Low ash coal-water mixed fuel comprising at least 80% by weight of pulverized coal having a particle size distribution of -200 mesh, based on 60 to 75% by weight of the total fuel, with the remainder being water. The low ash coal-water mixed fuel according to claim 1, wherein the amount of dispersant is 0.3 to 5% by weight based on coal. The low ash coal-water mixed fuel according to claim 2, wherein the amount of dispersant is 0.4% by weight based on coal. The low ash coal-water mixed fuel according to claim 1, wherein the amount of ammonia water used as the pH adjuster is 0.3 to 0.5% by weight based on coal. The low ash coal-water mixed fuel according to claim 1 or 4, wherein the amount of ammonia water to be used as the pH adjuster is 0.4% by weight based on coal. A method for producing a continuous low ash coal-water mixed fuel, comprising the following steps: (A) Coarse grinding so that at least 98% of coal is -50 mesh or less. (B) Coking process for the ash content to be 1 to 5% by weight based on coal. (C) A process of pulverizing at least 80% of coal to -200 mesh and simultaneously injecting a dispersant and ammonia water. (D) A high speed agitation process for homogenizing the produced low ash coal-water mixed fuel. The method for producing a continuous low ash coal-water mixed fuel according to claim 6, wherein the step (b) is a flotation step. The method for producing a continuous low ash coal-water mixed fuel according to claim 6, wherein a magnetic separator is provided after step (a) or (c). The method for producing a continuous low ash coal-water mixed fuel according to claim 6, wherein the dispersant is a naphthalene sulfonic acid formalin condensate ammonium salt having a molecular weight of 3000 to 10,000. The method for producing a continuous low ash coal-water mixed fuel according to claim 6 or 9, wherein the dispersant is injected in an amount of 0.1 to 1% by weight based on coal. The method for producing a continuous low ash coal-water mixed fuel according to claim 6, wherein 0.1 to 1% by weight of ammonia water is injected on a coal basis.

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