JPH0329273B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is applicable to water slurry containing a high concentration of carbonaceous solids such as coal, oil coke, and petroleum pitch, which have excellent combustibility and storage stability (hereinafter referred to as high concentration coal/water slurry). ). [Prior Art] In recent years, due to the instability of petroleum supply, the development of technology for effectively utilizing carbonaceous solids such as coal, oil coke, and petroleum-based pitch has been progressing. 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 kilns. However, in these various utilization technologies, carbonaceous solids are difficult to handle because they are solid at room temperature, and there is a risk of pollution due to dust scattering and dust explosions, making it difficult to use carbonaceous solids. It's summery. Therefore, it is desirable to convert these carbonaceous solids into a fluid to facilitate handling and prevent pollution and danger. On the other hand, in order to reduce the cost of transporting carbonaceous solids, it is effective to transport them in the form of a fluid. For the above purposes, it is effective to make a slurry as a method of fluidizing carbonaceous solids, but this slurry can be pyrolyzed, gasified, combusted, blown into a blast furnace, or used as fuel for a cement kiln. In order to use the slurry for such purposes, 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, as shown in Fig. 4, coal, water, a dispersant, and a stabilizer are supplied to a wet pulverizer 1 and then pulverized and mixed to obtain a stable slurry, or a wet pulverizer consisting of two or more chambers is used. A method of obtaining a stable slurry using the above method is known. [Problems to be Solved by the Invention] However, the above-mentioned conventional techniques all involve adding a dispersant and a stabilizer 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 the downstream classifier, increasing the coarse particle content of the product slurry. This causes problems such as poor flammability and storage stability. The present invention was made to solve the above-mentioned problems, and aims to provide a method for economically producing a highly concentrated coal/water slurry having excellent combustibility and storage stability. [Means and effects for solving the problems] The method for producing a highly concentrated coal/water slurry of the present invention is a method for producing a highly concentrated coal/water slurry by mixing coal, water, a dispersant, and a stabilizer. The method is characterized in that coal, water, and a dispersant are supplied to the front part of the wet pulverizer, and a stabilizer is supplied to the rear half of the length of the wet pulverizer. A detailed description will be given below based on the drawings. FIG. 1 is a flow sheet showing an example of the present invention. Raw coal is placed at the inlet 2 of a wet crusher 1 such as a ball mill.
Water and a dispersant are supplied, and a stabilizing agent is supplied to the rear half of the length of the wet crusher 1. 3 is the exit. If the stabilizer is supplied to the front half (inlet side) of the wet crusher 1 in the length direction, the viscosity increases and the crushing power increases, which is uneconomical. Therefore, in the present invention, the position of adding the stabilizer is
Rear part (outlet side) of 1/2 of the length of wet crusher 1
It is limited to. FIG. 2 shows another example of the invention. That is, a porous partition plate 4 is provided in the wet crusher 1 so that coal slurry having a certain particle size or less moves to the rear. The other configurations are the same as in the case of FIG. Further, as shown in FIG. 3, a wet crusher may be used in which a plurality of porous partition plates 4 are provided to form multiple chambers. As shown in Figures 2 and 3, even when using a wet pulverizer consisting of two or more chambers, the stabilizing agent should be added to a chamber at the rear of the 1/2 length of the wet pulverizer. do it like this. 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 salts,
Higher alcohol sulfate salts, nonionic ether sulfate salts, olefin sulfate salts,
Alkylaryl sulfonate, dibasic acid ester sulfonate, dialkyl sulfosuccinate, acyl sarcosinate, alkylbenzene sulfonate, alkyl sulfate ester salt, polyoxyethylene alkyl (alkylphenol) sulfate ester salt, alkyl phosphoric acid Ester salt, dialkyl sulfosuccinate ester salt, acrylic acid or/
and maleic anhydride copolymers, polycyclic aromatic sulfonates, or formalin compounds, etc. As cationic surfactants, alkyl amine salts, quaternary amine salts, etc. are used, and nonionic surfactants Examples include polyoxyalkyl ether, polyoxyethylene alkyl phenol ether, oxyethylene/oxypropylene block polymer, polyoxyethylene alkylamine, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, alkyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride. , alkylpyridinium salts, polyoxyethylene fatty acid esters, aliphatic 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 sodium naphthalene sulfonate, its formalin condensate, and sodium dicyclopentadiene sulfonate are used. A copolymer of salt and sodium acetate is used, and the amount is 0.001 to 5% by weight, preferably 0.05 to 5% by weight based on the carbonaceous solid.
Added at 1.5% by weight. In addition, the stabilizers used in the present invention include alkali metal salts of carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), alkali metal salts of polyacrylic acid, polyvinyl alcohol, starch, karaya gum,
Mixtures of karaya gum and polyacrylamide, polysaccharides modified with polyacrylates, alkali metal salts of alginic acid, bentonite, gums such as arabic gum, guar gum, loin cast bean gum, tragacanth gum, British gum, Senegal gum, crystal gum, etc. are used. 0.0001 to 5.0% by weight based on carbonaceous solids, preferably
It is added in an amount of 0.001 to 1.5% by weight. [Example] Examples and comparative examples are listed below. Example A wet ball mill with an inner diameter of 480 mm and a length of 960 mm was used as a wet crusher, and according to the flow shown in Figure 1, a stabilizer was injected at a position 640 mm from the ball mill entrance, and coal with an HGI of 50 was injected at a high concentration. It was pulverized to produce a highly concentrated coal/water slurry with a product slurry concentration of 66% and a 200 mesh passing rate of 80%. In addition, 0.8% by weight of sodium salt of naphthalene sulfonic acid formamide condensate was added as a dispersant based on coal.
As a stabilizer, sodium salt of carboxymethyl cellulose was added in an amount of 0.005% by weight based on coal.
The results were as shown in the following table. Comparative Example Using the same wet ball mill as in the example, a highly concentrated coal/water slurry having the same concentration and particle size as in the example 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 the following table.

〔Effect of the invention〕

As explained above, in the method of the present invention, the stabilizing agent and the dispersing agent are not simultaneously supplied to the inlet of the wet pulverizer, but the stabilizer is added at the rear part of the wet pulverizer from 1/2 of the length. Therefore, compared to the conventional method, the crushing power is small and economical, and the mixing effect in the crusher is improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one example of the method of the present invention, FIGS. 2 and 3 are explanatory diagrams showing other examples of the method of the present invention, and FIG. 4 is an explanatory diagram showing a conventional method. 1... Wet crusher, 2... Inlet, 3... Outlet, 4... Porous partition plate.

Claims (1)

[Claims] 1. A method for producing a highly concentrated coal/water slurry by mixing coal, water, a dispersant, and a stabilizer, the method comprising: supplying coal, water, and a dispersant to the front of a wet pulverizer; A method for producing a highly concentrated coal/water slurry, characterized by supplying a stabilizer to the rear half of the length of a wet crusher. 2. A method for producing a highly concentrated coal/water slurry according to claim 1, which uses a wet pulverizer having two or more chambers.