JPH0335355B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to a dispersant for coal-water slurry.
More specifically, the present invention relates to a dispersant that disperses coal powder in water and provides a fluidized coal-water slurry even with a high concentration of coal. (Problems to be Solved by the Prior Art and the Invention) Petroleum, which has been widely used as an energy source, has seen a significant rise in its price and there are concerns that it will run out. Therefore, the challenge is to develop other energy sources that can provide a stable supply, and coal is once again becoming widely available. However, the biggest problem in using coal is transportation problems due to the fact that coal is solid. BACKGROUND ART Conventionally, mined coal is pulverized into powder, which is made into a coal-water slurry to be fluidized and transported by pipeline. On the other hand, COM (Coal−
Although oil-Mixture) has reached the practical stage,
Since oil is used, there are problems in terms of stable supply and price, and high concentration coal-water slurry is seen as a promising coal utilization technology in the future. This slurry technology of coal in water is about to be used in an extremely wide range of coal uses, such as direct coal combustion and gasification, in addition to the above-mentioned coal pipeline transportation, and is becoming an important issue in coal use. ing. It is preferable for this coal-water slurry to be a highly concentrated slurry with little water content from the economic and pollution prevention viewpoints. In particular, in the case of direct combustion of coal-water slurry, which can eliminate wastewater treatment and pollution problems, the coal-water slurry is passed through a cyclone or turbulent burner without dehydration, drying, etc. Since it is charged and burned directly in the furnace, it is necessary to reduce the moisture content as much as possible. However, when attempting to increase the concentration of coal powder using known techniques, the slurry becomes significantly thickened and loses fluidity. On the other hand, if the concentration of coal powder in the slurry is lowered, transportation efficiency, combustion efficiency, etc. will decrease, and if the coal-water slurry is used after being dehydrated, the dehydration and drying processes will also be costly. There are other problems, such as pollution problems. Conventionally, various dispersants for coal-water slurries have been proposed to solve such problems. For example, sodium oleate, sodium dodecylbenzenesulfonate, alkyl group arylsulfonate,
polyoxyethylene alkyl phenyl ether,
These include surfactants such as stearylamine rochloride, and water-soluble polymers such as polyethylene liquor, polyacrylamide, celluloses, sodium polyacrylate, sodium ligninsulfonate, and sodium naphthalenesulfonate/formalin condensate. However, both have insufficient fluidity and lack practicality. The present inventors have continued to conduct research to solve the above-mentioned problems in dispersants for coal-water slurries, and have found that a certain water-soluble copolymer is excellent as a dispersant for coal-water slurries. The present invention was completed based on the discovery that the present invention is effective. That is, the present invention provides a dispersant for easily producing a coal-water slurry that has fluidity even at high concentrations. (Means and effects for solving the problems) The present invention has the general formula (However, in the formula, R is hydrogen or a methyl group, X is an alkylene group having 2 to 4 carbon atoms, and n is 1 to 4 on average.
100, and Y is derived from hydrogen, an alkyl group having 1 to 30 carbon atoms, an alkenyl group, an aryl group, an alkyl group having an aryl group as a substituent, a cyclic alkyl group, a cyclic alkenyl group, or a heterocyclic compound. represents a monovalent organic group. ) 1 selected from polyalkylene glycol mono(meth)acrylate monomers () represented by
species or two or more species and general formula (However, in the formula, Z represents an alkylene group having 1 to 4 carbon atoms, and M represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group, or an amine base.) From a sulfoalkyl acrylate monomer () represented by one or more selected monomers are essential components, the molar ratio of the monomer () to the monomer () is in the range of 1:5 to 1:500, and the monomer ( ) and a water-soluble copolymer obtained from raw material monomers in which the sum of the monomers () is 50% or more of the total monomers. The coal used in the coal-water slurry is, for example,
Any type of coal, such as anthracite, bituminous coal, sub-bituminous coal, lignite, etc., can be used regardless of its type and origin, as well as its moisture content and chemical composition. Such coal can be milled by wet or dry grinding using conventional methods to produce 200 mesh passes of 50
The standard for use is 70 to 80% by weight or more, preferably 70 to 80% by weight. Further, the slurry concentration is 60 to 90% by weight on a dry basis of pulverized coal, and if it is less than 60% by weight, it is not practical from the viewpoints of economic efficiency, transportation efficiency, combustion efficiency, etc. The water-soluble copolymer that is effective as a dispersant for coal-water slurry of the present invention has monomer () and monomer () as essential components, and has a molar ratio of monomer () and monomer (). The ratio is in the range of 1:5 to 1:500, more preferably 1:20 to 1:200, and the total of monomer () and monomer () is 50 mol% or more of the total monomers. Obtained from a certain raw material monomer. The monomer () is represented by the above general formula and can be obtained by a known method. Examples of monomers () include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polybutylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, and methoxypolypropylene glycol mono(meth)acrylate. meth)acrylate, methoxypolybutylene glycol mono(meth)acrylate, ethoxypolyethylene glycol mono(meth)acrylate, ethoxypolypropylene glycol mono(meth)acrylate, ethoxypolybutylene glycol mono(meth)acrylate, methoxypolyethylene glycol polypropylene glycol mono(meth)acrylate In addition to meth)acrylates, alkoxypolyethylene glycol mono(meth)acrylates alkoxylated with an alkyl group having up to 30 carbon atoms: Alkenoxypolyethylene glycol mono(meth)acrylates alkenoxylated with an alkenyl group having up to 30 carbon atoms. Acrylates: phenoxypolyethylene glycol mono(meth)acrylate, nonyl phenoxypolyethylene glycol mono(meth)acrylate, naphthoxypolyethylene glycol mono(meth)acrylate, phenoxypolypropylene glycol mono(meth)acrylate, naphthoxypolyethylene Aryloxy polyalkylene glycol mono (meth) acrylates such as glycol/polypropylene glycol mono (meth) acrylate, p-methylphenoxy polyethylene glycol mono (meth) acrylate: Alkyl kilograms such as benzyloxy polyethylene glycol mono (meth) acrylate Cyclopolyalkylene glycol mono(meth)acrylates: cyclohexoxypolyethylene glycol mono(meth)
Cyclic alkoxypolyalkylene glycol mono(meth)acrylates such as acrylates: Cyclic alkenoxypolyalkylene glycol mono(meth)acrylates such as cyclopentenoxypolyethylene glycol mono(meth)acrylate:
Examples include heterocyclic ethers of polyalkylene glycol mono(meth)acrylates such as pyridyloxypolyethylene glycol mono(meth)acrylate and thienyloxypolyethylene glycol mono(meth)acrylate, and one or two of these The above can be used. Further, the monomer () is similarly represented by the above general formula, and can also be obtained by a known method. Examples of the monomer () include 2-sulfoethyl acrylate, 3-sulfopropyl acrylate, 2-sulfopropyl acrylate,
1-sulfopropan-2-yl acrylate, 4
- Examples include sulfobutyl acrylate and their alkali metal salts such as sodium and potassium, alkaline earth metal salts such as magnesium and calcium, ammonium salts, and organic amine salts, and one or more of these may be used. I can do it. The molar ratio of monomer () to monomer () is in the range of 1:5 to 1:500, and if the ratio is outside this range, the copolymer with excellent dispersion performance will result. Can't get union. In addition to these monomers () and monomers (), monomers () copolymerizable with these monomers can be used within a range of less than 50 mol% of the total monomers. . Examples include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts of these acids, and alcohols with these acids. For example, esters such as methyl (meth)acrylate obtained: various sulfones other than the monomer () such as vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-acrylamide 2-methylpropanesulfonic acid, etc. Acids and their monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts; Various (meth)acrylamides such as (meth)acrylamide and N-methylol (meth)acrylamide; Aromas such as styrene and p-methylstyrene. Group vinyl compounds; examples include vinyl acetate, propenyl acetate, vinyl chloride, etc., and one or more of these can be used. The usage amount of these monomers () and monomers () that can be copolymerized with monomers () is 50 mol% of the total monomers.
If used in an amount exceeding this range, the dispersion performance of the resulting copolymer will deteriorate. In the present invention, in order to produce a water-soluble copolymer, the monomer components may be copolymerized using a polymerization initiator. Copolymerization can be carried out by methods such as polymerization in a solvent or bulk polymerization. Polymerization in a solvent can be carried out either batchwise or continuously, and the solvents used in this case include water:
Lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol: benzene,
Examples include aromatic or aliphatic hydrocarbons such as toluene, xylene, cyclohexane, and n-hexane; ethyl acetate; and ketone compounds such as acetone and methyl ethyl ketone. In view of the solubility of the raw material monomer and the resulting copolymer, and the convenience of using the copolymer, at least one selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms should be used. is preferred. Among the lower alcohols having 1 to 4 carbon atoms, methyl alcohol, ethyl alcohol, and isopropyl alcohol are particularly effective. When polymerization is carried out in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as the polymerization initiator. At this time, an accelerator such as sodium hydrogen sulfite can also be used in combination. Also, lower alcohols,
For polymerization using aromatic hydrocarbons, aliphatic hydrocarbons, ethyl acetate or ketone compounds as solvents, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; azobisisobutyronitrile Aliphatic azo compounds such as, etc. are used as polymerization initiators. At this time, a promoter such as an amine compound can also be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from among the various polymerization initiators or combinations of polymerization initiators and accelerators mentioned above. The polymerization temperature is appropriately determined depending on the solvent and polymerization initiator used, but it is usually carried out within the range of 0 to 120°C. Bulk polymerization uses peroxides such as benzoyl peroxide and lauroyl peroxide, hydroperoxides such as cumene hydroperoxide, and aliphatic azo compounds such as azobissobutyronitrile as polymerization initiators at a temperature of 50 to 150°C. done within the range. In addition, the molecular weight of the copolymer can be used in a wide range, but considering its performance as a dispersant for coal-water slurry, it is in the range of 1,000 to 500,000, especially 5,000,000 to 500,000.
A range of ~300,000 is preferred. The dispersant for coal-water slurries of the present invention is used in pulverized coal-water slurries, but the amount added is not particularly limited and is effective over a wide range of amounts. 0.05-2% by weight (dry basis), preferably 0.1-1
It is used in a proportion of % by weight. In order to use the dispersant for coal-water slurry of the present invention, the dispersant may be mixed with coal in advance to form a slurry, or the dispersant may be dissolved in water in advance. May be used. Of course, a predetermined amount of the dispersant may be mixed all at once, or may be used batchwise. Furthermore, due to the nature of the dispersant, any device for slurrying coal in water may be used as the slurry device. By these addition methods and slurry making methods,
The scope of the present invention is not limited. Moreover, a rust preventive agent, a corrosion preventive agent, an antioxidant, an antifoaming agent, an antistatic agent, a solubilizer, and the like can be added to the dispersant for coal-water slurry of the present invention as required. (Effects of the Invention) The dispersant for coal-water slurry of the present invention has excellent dispersibility of coal in water, and provides highly fluid and highly concentrated coal-water slurry with the addition of a small amount of dispersant. It is possible. By applying the highly concentrated coal-water slurry obtained using the dispersant for coal-water slurry of the present invention, it becomes possible to economically transport coal by pipeline, and it is possible to transport solid coal by combustion. The above problems can be resolved. Therefore, the dispersant for coal-water slurry of the present invention can greatly contribute to the spread of coal utilization technologies such as direct combustion of coal and coal gasification. (Example) Next, the dispersant for coal-water slurry of the present invention will be described in more detail by giving comparative examples and examples, but of course the present invention is not limited thereto. In the examples, unless otherwise specified, parts are by weight. Example 1 200 parts of water was charged into a polymerization container equipped with a thermometer, a stirrer, two dropping funnels, a gas introduction pipe, and a reflux condenser, and while stirring, the inside of the polymerization container was replaced with nitrogen, and the mixture was heated to 95% in a nitrogen atmosphere. heated to ℃. Thereafter, 10 parts of methoxypolyethylene glycol monoacrylate (containing an average of 50 ethylene oxide units per molecule) as a monomer (), 90 parts of sodium salt of 2-sulfoethyl acrylate as a monomer (), and water. 150 parts of the solution was added dropwise over 120 minutes, and a solution containing 0.4 parts of ammonium persulfate and 50 parts of water was added dropwise over 140 minutes from the other dropping funnel. After the dropwise addition was completed, polymerization was further continued at the same temperature for 1 hour and then cooled to obtain an aqueous solution of copolymer (1) having an average molecular weight of 60,000. Examples 2 to 11 Monomers () and monomers () shown in Table 1
And if necessary, monomer () was used in the monomer composition (mol%) shown in Table 1, and polymerization was carried out by a conventional method to obtain aqueous solutions of copolymers (2) to (11). . Comparative Examples 1 and 2 Comparative (co)polymers (1) and (2) were obtained by polymerizing in a conventional manner using the monomer compositions shown in Table 1.

【table】

[Table] Example 12 Copolymers (1) to (11) obtained in Examples 1 to 11
Coal (bituminous coal) pulverized to pass 74% through a 200-mesh sieve was added little by little at room temperature to an aqueous solution prepared to contain the following in the amount shown in Table 2 with stirring. After adding the entire amount to give the coal concentration shown in Table 2, the mixture was stirred for 3 minutes at 5000 RPM using a homo mixer (manufactured by Tokushu Kikako) to prepare a coal-water slurry. The viscosity of the obtained coal-water slurry was measured at 25°C to evaluate the fluidity. The results are shown in Table 2. Low viscosity indicates good fluidity. Also, for comparison, comparative (co)polymer (1) ~
(2) Sodium polyacrylate (average molecular weight 60,000) or polyethylene glycol (average molecular weight
21500) as a dispersant and the results of comparative examples in which no dispersant was used at all are also listed in Table 2.

[Table] ×: Defective

Claims (1)

[Claims] 1. General formula (However, in the formula, R is hydrogen or a methyl group, X is an alkylene group having 2 to 4 carbon atoms, and n is 1 to 4 on average.
100, and Y is derived from hydrogen, an alkyl group having 1 to 30 carbon atoms, an alkenyl group, an aryl group, an alkyl group having an aryl group as a substituent, a cyclic alkyl group, a cyclic alkenyl group, or a heterocyclic compound. represents a monovalent organic group. ) 1 selected from polyalkylene glycol mono(meth)acrylate monomers () represented by
species or two or more species and general formula (However, in the formula, Z represents an alkylene group having 1 to 4 carbon atoms, and M represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group, or an amine base.) From a sulfoalkyl acrylate monomer () represented by one or more selected monomers are essential components, the molar ratio of the monomer () to the monomer () is in the range of 1:5 to 1:500, and the monomer ( ) and a water-soluble copolymer obtained from raw material monomers in which the total amount of the monomer () is 50 mol % or more based on the total monomers.