JPH0329271B2 - - Google Patents

Description

[Detailed description of the invention]

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. Petroleum, which has traditionally been widely used as an energy source, has seen a significant rise in its price, and there are concerns about its depletion. 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−
Oil-Mixture) has reached the practical stage, but
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 moisture from economical 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, surfactants such as sodium oleate, sodium dodecylbenzenesulfonate, alkylaryl sulfonate, polyoxyethylene alkyl phenyl ether, stearylamine hydrochloride, polyethylene glycol, polyacrylamide, celluloses, sodium polyacrylate, and lignin sulfone. Examples include water-soluble polymers such as acid soda and sodium naphthalene sulfonate/formalin condensate. However, both have insufficient fluidity and lack practicality. The present inventors continued intensive research to solve the above-mentioned problems in dispersants for coal-water slurries, and found that a certain water-soluble copolymer has excellent effects as a dispersant for coal-water slurries. The present invention was completed based on the discovery that the present invention has the following properties. That is, the present invention provides a dispersant for easily producing a coal-water slurry that has fluidity even at high concentrations. The present invention is based on the general formula _CH2 =C(CH3)COO( _-XO ) _-oY (wherein, X is an alkylene group having 2 to 4 carbon atoms, n is a number of 1 to 100 on average, Y is hydrogen,
It represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, or an alkylphenyl group having 1 to 3 alkyl groups having 1 to 9 carbon atoms as substituents. ) A polyalkylene glycol monomethacrylate monomer () represented by the general formula (However, in the formula, Z represents an alkylene group having 1 to 4 carbon atoms, and R ₁ and R ₂ represent an alkyl group having 1 to 5 carbon atoms.) (However, in the formula, Z represents an alkylene group having 1 to 4 carbon atoms, R ₁ and R ₂ represent hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ₃ represents hydrogen or an alkyl group having 1 to 5 carbon atoms. or a benzyl group, m is an integer of 1 or 2, and M represents an anion. is an essential component, the molar ratio of the monomer () to the monomer () is in the range of 1:2 to 1:500, and the monomer () to the monomer () The present invention relates to a dispersant for coal-water slurry comprising a water-soluble copolymer obtained from raw material monomers whose total amount is 50 mol% or more based on 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 1:2 to 1:500, more preferably 1:10 to 1:200, and the total of monomer () and monomer () is 50 mol% or more of the total monomers. Obtained from certain raw material monomers. The monomer () is represented by the above general formula and can be obtained by a known method. Examples of monomers () include polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, polybutylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, methoxypolypropylene glycol monomethacrylate, methoxypolybutylene glycol monomethacrylate, ethoxypolyethylene glycol monomethacrylate , Ethoxypolypropylene glycol monomethacrylate, Ethoxypolybutylene glycol monomethacrylate, Methoxypolyethylene glycol
Examples include polypropylene glycol monomethacrylate, and one or more of these can be used. In addition, the monomer () may be dialkylaminoalkyl methacrylate or 4
This is at least one type of ammonium chloride methacrylate, which is also a known method, such as a method of transesterifying methyl methacrylate and a dialkylamino alcohol to obtain a dialkylaminoalkyl methacrylate, or a method of converting dialkylaminoalkyl methacrylate to an alkyl halide, benzyl halide, or dialkyl halide. 4 such as sulfuric acid and hydrochloric acid
It can be obtained by using a grading agent to form quaternary ammonium chloride methacrylate. Examples of the monomer () include dialkylaminoalkyl methacrylates such as dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, diethylaminopropyl methacrylate, and methyl chloride quaternized product of dimethylaminoethyl methacrylate (β-methacryloxy ethyltrimethylammonium chloride), benzyl chloride quaternized product of dimethylaminoethyl methacrylate, dimethyl sulfate quaternized product of dimethylaminoethyl methacrylate, hydrochloric acid quaternized product of dimethylaminoethyl methacrylate, methyl chloride quaternized product of diethylaminoethyl methacrylate, etc. Examples include ammonium chloride methacrylates, and one or more of these can be used. The molar ratio of monomer () to monomer () is in the range of 1:2 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 of this include methyl (meth)acrylate, which is obtained from alcohols and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid;
■■■ Various esters such as 2-hydroxyethyl acrylate; Various (meth)acrylamides such as (meth)acrylamide and N-methylol (meth)acrylamide; Aromatic vinyl compounds such as styrene and p-methylstyrene; Vinyl acetate, Examples include propenyl acetate and vinyl chloride, and one or more of these can be used. The amount of these monomers () and monomers () that can be copolymerized with monomers () is within the range of less than 50 mol% of the total monomers, and if used in large amounts exceeding this range, The dispersion performance of the resulting copolymer deteriorates. 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 solvent used in this case is 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; 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 is carried out using peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; and aliphatic azo compounds such as azobisisobutyronitrile as polymerization initiators at 50 to 150°C. carried out within a temperature 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 water-soluble copolymer thus obtained can be used as it is as a dispersant for the coal-water slurry of the present invention, but if necessary, it may be further converted into a quaternary ammonium salt using a known quaternizing agent. . Preferred examples of such quaternizing agents include alkyl halides such as methyl chloride, benzyl halides such as benzyl chloride, and dialkyl sulfates such as dimethyl sulfate. 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. Next, the dispersant for coal-water slurry of the present invention will be explained 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 the inside of the polymerization container was replaced with nitrogen while stirring, and the mixture was heated to 95% in a nitrogen atmosphere. heated to ℃. Thereafter, 8 parts of methoxypolyethylene glycol monomethacrylate (containing an average of 20 ethylene oxide units per molecule) as a monomer () and 92 parts of methyl chloride quaternized dimethylaminoethyl methacrylate as a monomer () A solution of 0.4 parts of ammonium persulfate and 50 parts of water was added dropwise over 70 minutes from one dropping funnel. After the dropwise addition, polymerization was continued for 60 minutes at the same temperature, then cooled, and the average molecular weight was 10.
An aqueous solution of Copolymer 1 was obtained. Examples 2 to 8 Monomers () and monomers () shown in Table 1
and, if necessary, monomers () in the monomer compositions (mol%) shown in Table 1, polymerization was carried out according to the method carried out in Example 1, and copolymers (2) to (8)
An aqueous solution of was obtained.

[Table] Example 9 200 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 the inside of the polymerization container was replaced with nitrogen while stirring to create a nitrogen atmosphere. It was heated to 95°C in a chamber. Thereafter, a solution of 8 parts of methoxypolyethylene glycol monomethacrylate (containing an average of 20 ethylene oxide units per molecule) as a monomer (), 69.6 parts of dimethylaminoethyl methacrylate as a monomer () and 150 parts of water was prepared. was added dropwise over 60 minutes, and a solution of 0.4 parts of ammonium persulfate and 50 parts of water was added dropwise from the other dropping funnel over 70 minutes. After the dropwise addition was completed, polymerization was further continued for 60 minutes at the same temperature and then cooled to obtain an aqueous solution of a copolymer with an average molecular weight of 100,000. To the obtained copolymer aqueous solution, 56 parts of dimethyl sulfuric acid was added dropwise over 120 minutes, and after the dropwise addition was completed, the reaction was carried out at a reaction temperature of 50°C for 300 minutes to form an aqueous solution of the quaternized copolymer (9). I got it. Comparative Example 1 An aqueous solution of comparative polymer (1) having an average molecular weight of 100,000 was obtained in exactly the same manner as in Example 1, except that the monomer () in Example 1 was not used. Example 10 A 200 mesh sieve was added to a 74% aqueous solution containing the copolymers (1) to (9) obtained in Examples 1 to 9 in the amounts shown in Table 2. Pass-pulverized coal (bituminous coal) was added little by little at room temperature while stirring. After adding the entire amount to achieve the coal concentration shown in Table 2, the coal was stirred for 3 minutes at 5000 RPM using a homo mixer (manufactured by Tokushu Kikako).
A water slurry was prepared. 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. For comparison, comparative polymer (1) obtained in Comparative Example 1, sodium polyacrylate (average molecular weight 6
Table 2 also shows the results of comparative examples when polyethylene glycol (average molecular weight: 21,500) or polyethylene glycol (average molecular weight: 21,500) was used as a dispersant, and when no dispersant was used at all.

[Table] ×: Defective

Claims (1)

[Claims] 1 General formula CH ₂ =C(CH ₃ )COO(-XO)- _o Y (wherein, X is an alkylene group having 2 to 4 carbon atoms, and n is a number on average from 1 to 100) , Y is hydrogen,
It represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, or an alkylphenyl group having 1 to 3 alkyl groups having 1 to 9 carbon atoms as substituents. ) A polyalkylene glycol monomethacrylate monomer () represented by the general formula (However, in the formula, Z represents an alkylene group having 1 to 4 carbon atoms, and R ₁ and R ₂ represent an alkyl group having 1 to 5 carbon atoms.) (However, in the formula, Z represents an alkylene group having 1 to 4 carbon atoms, R ₁ and R ₂ represent hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ₃ represents hydrogen or an alkyl group having 1 to 5 carbon atoms. or a benzyl group, m is an integer of 1 or 2, and M is an anion.) at least one monomer selected from the group consisting of quaternary ammonium chloride methacrylate ( as an essential component, the molar ratio of the monomer () to the monomer () is in the range of 1:2 to 1:500, and the sum of the monomer () and the monomer () A dispersant for coal-water slurry comprising a water-soluble copolymer obtained from raw material monomers in which the amount is 50 mol% or more based on the total monomers.