JPH0132876B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for improving the fluidity of coal/water slurry, and more specifically, the present invention relates to a method for improving the fluidity of coal/water slurry. It also relates to a method of making slurry. In recent years, coal has been reconsidered as an alternative energy source to petroleum, despite the deterioration of the oil supply situation, as it is rich in resources, has vast reserves, and is distributed throughout the world. However, coal is a bulk material and has various problems in terms of handling. In particular, unlike petroleum, which is a liquid, transporting it requires enormous capital investment, power, and labor, and in the case of coal powder, it is also necessary to take measures to prevent deterioration of the working environment due to dust generation and spontaneous combustion. Liquefaction and gasification of coal have been considered for a long time as a solution to these problems, but it is said that it will take a considerable amount of time to put them into practical use. As a link or as a method of supplying raw materials during liquefaction or gasification, fluidization by dispersing coal powder in a liquid such as water, petroleum, or methanol is considered. Among these methods, the method of dispersing coal powder in water to form a slurry has various advantages because the medium is water, and has already been put into practical use for long-distance overland pipeline transportation of coal from the base of a mountain. However, increasing the coal concentration in the slurry significantly deteriorates the fluidity of the slurry, so currently it is carried out at a coal concentration of 45 to 60% by weight.
Therefore, at present, there are problems in terms of transportation efficiency, dewatering efficiency, wastewater treatment cost, combustion efficiency in the case of direct combustion in a boiler, etc., and it has not become widely used. In order to increase the coal concentration in this coal powder/water slurry as much as possible, various methods have been proposed, such as adjusting the particle size of the coal powder and reducing the viscosity of the slurry by adding a dispersant. For example, JP-A-53-581 discloses a method for obtaining a highly concentrated coal/water slurry by adding organic sulfonate or lignin sulfonate together with ammonium hydroxide; Although the slurry viscosity decreases considerably,
The reality is that it is not used industrially because it is not completely satisfactory. In order to utilize lignin, which is a renewable resource, in this field, the present inventors have conducted various studies on the interaction between coal powder and lignin derivatives. The inventors have discovered that a reaction product of a lignin sulfonate, formaldehyde or glyoxal, and an aminosulfonic acid or a salt thereof is superior to the so-called lignin sulfonate as a dispersant for coal/water slurry, and has thus arrived at the present invention. The above-mentioned reactant used as a dispersant in the present invention is disclosed in Japanese Patent No. 533042 entitled "Sulfite pulp effluent modified product and method for producing the same" [Applicant: Sanyo Pulp Co., Ltd.
Sanyo Kokusaku Pulp Co., Ltd.], and the reactant may be used as it is, or only high molecular weight fractions may be separated from the reactant and used. That is, as aminosulfonic acid or its salt, n in NH ₂ (CH ₂ )nSO ₃
=0 to 2, X=H, or any of an alkali metal and an alkaline earth metal. The reaction is alkaline and usually carried out at a temperature of 70°C or higher. The above ratio is the composition of the reactants.
It is preferably 5 to 50 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight. The amount of the above reactant added is 100% of the absolute dry weight of coal powder.
It is 0.2 to 2 parts by weight. If it is less than 0.2 parts by weight, the improvement effect on fluidity will be small;
Moreover, even if the amount is more than 2 parts by weight, hardly any additional effect can be expected, or on the contrary, it becomes worse. The addition time may be at the time of preparing the coal powder/water slurry or at the time of coal pulverization. Although the method of the present invention is effective regardless of the coal concentration in the slurry, it is particularly significant in high-concentration slurries with a coal concentration of 60% by weight or more. In addition, in the method of the present invention, polyoxyalkylene alkyl phenyl ether, alkylbenzene sulfonate, (alkyl) naphthalene sulfonate or its formalin condensate, carboxymethyl cellulose, polyacrylate, condensed phosphate, etc. are further used as fluidity improvers. It is also possible to use known additives such as. The present invention will be further explained below with reference to Examples.
The present invention is not limited to these examples. Although the details of the dispersion mechanism of the product of the present invention are unknown, it is generally said that when a surfactant is adsorbed to the interface between coal particles and water, the coal particles are broken up and prevented from coagulating with each other. , the reactants of the present invention are considered to have excellent surface activity. Example 1 Product name Sunextract 252 (product of Sanyo Kokusaku Pulp Co., Ltd.)
Main ingredient, sodium ligninsulfonate, concentration 43
10% by weight of glyoxal and 20% by weight of sulfanilic acid based on the solid content (wt%) were added and mixed with stirring, and 40% NaOH was added to this mixture to adjust the pH to 8.2.
After that, the reaction product (ALS-1) obtained by heat treatment at 90℃ for 2 hours and untreated Sun Extract 252
(Comparative example) relative to absolute dry weight of coal in terms of solid content
To 169 g of each aqueous solution containing the equivalent of 0.1, 0.3, 1.0, 2.0, and 2.5% by weight, 200 meshes of 331 g of Miike charcoal (moisture 1.9%) finely ground to 80% pass were added, Using T・K homomixer
The mixture was stirred at 8000 rpm for 40 minutes to prepare a coal/water slurry with a coal concentration of 65% by weight. The liquid temperature of this slurry was adjusted to 20°C, and the slurry viscosity was measured using a B-type rotational viscometer, and the results shown in Table 1 were obtained. The viscosity was measured 4 minutes after the rotor started rotating, and was expressed as a value converted to No. 3 rotor 30 rpm.

[Table] The slurry prepared by the method of the present invention had a considerably lower apparent viscosity than the slurry of the comparative example and exhibited good fluidity. Example 2 Na-based sulfite pulp wastewater with a concentration of 20% by weight was separated using a polysulfone ultrafiltration membrane with a molecular weight cut off of 5000, and high-purity sodium ligninsulfonate (PH7) with a purity of 90% and a 5% by weight aqueous solution was separated. LS−Na
-1) was obtained. To this 25% liquid of LS-Na-1, 10% by weight of formalin and 15% by weight of taurine based on the solid content were added, and after stirring and mixing, 40% NaOH was added to this to adjust the pH to 9. was refluxed for 3 hours, and the reactant
ALS-2 was obtained. ALS-2 of the present invention, LS-Na-1 of the comparative example
Each was added in an amount of 1.0% by weight based on the absolute dry weight of coal in terms of solid content, and slurries with coal concentrations of 63% and 65% by weight were prepared in the same manner as in Example 1. After adjusting the temperature of the obtained slurry to 20°C, the slurry viscosity was measured in the same manner as in Example 1, and the results shown in Table 2 were obtained.

[Table] As shown in the above examples, the addition of the reactant of the present invention significantly lowers the apparent viscosity of the slurry compared to the conventional addition of sulfite pulp wastewater (Table 1, Table 1). Table 2), the present invention was completed with improved fluidity. The slurry produced by the method of the present invention had a lower apparent viscosity than the comparative example and exhibited good fluidity both when the concentration was low and when the concentration was high.

Claims (1)

[Scope of Claims] 1. When preparing a coal powder/water slurry, at least a part of the dispersant contains sulfite pulp cooking effluent or a lignin sulfonate obtained by fractionation therefrom, formaldehyde or glyoxal, and aminosulfonic acid or The alkaline heating reaction product with its salt is coal powder bone dry weight
A method for improving the fluidity of coal/water slurry, characterized by adding 0.2 to 2 parts by weight per 100 parts by weight. 2. The method for improving the fluidity of a coal/water slurry according to claim 1, wherein the coal concentration of the coal/water slurry is 60% by weight or more.