JPH0149192B2 - - 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. Conventionally, mined coal is pulverized into powder, which is made into a coal-water slurry, fluidized, and transported by pipeline.
On the other hand, COM (Coal-Oil), which can be transported by pipeline,
-Mixture) is currently undergoing demonstration experiments, but since it uses oil, there are problems with stable supply and price, and high-concentration coal-water slurry is promising as a coal utilization technology in the future. being watched. 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 a small 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 sent to 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. The reason for this need not be mentioned here, but is described in detail in the specification of JP-A-57-21488. However, when attempts are made to increase the concentration of coal powder in water using known techniques, the slurry becomes significantly thickened and loses fluidity. On the other hand, if the concentration of coal powder in water is lowered, transportation efficiency, combustion efficiency, etc. will decrease, and if a water slurry of coal is used after dehydration, the dehydration and drying processes will also be costly. There are problems such as causing pollution problems. Conventionally, various dispersants for coal-water slurries have been proposed to solve such problems. For example, surfactants such as sodium oleate, sodium dodecyl benzene sulfonate, alkyl allyl sulfonate, polyoxyethylene alkyl phenyl ether, stearylamine hydrochloride, polyethylene glycol, polyacrylamide, cellulose, polyester, etc. Examples include water-soluble polymers such as sodium acrylate. but,
Both have insufficient fluidity and lack practicality. The present inventors have carried out intensive research to solve the above-mentioned problems in dispersants for coal-water slurries, and as a result, a composition containing a certain polyether derivative and a copolymer has been found to be suitable for dispersing agents for coal-water slurries. The present invention has been completed based on the discovery that it has an excellent effect as a dispersant for commercial use. That is, the present invention provides a dispersant for easily producing a coal-water slurry that has fluidity even at high concentrations. That is, the dispersant for coal-water slurry of the present invention has the following general formula: (A) A [(R ₁ O) _l (CH ₂ CH ₂ O) _n ) H ₎ Residues of alcohols, phenols, amines, carboxylic acids, and derivatives thereof having one or more R ₁
is an alkylene oxide residue having 3 to 4 carbon atoms, l
is the average number of added moles of ethylene oxide, 0 to 100, m is the average number of added moles of ethylene oxide, 50 to 1000, n
(B) polyalkylene glycol monoallyl ether (a), maleic acid monomer (b), and copolymerizable with these. The present invention relates to a dispersant for coal-water slurry, characterized in that it contains a copolymer () derived from a monomer (c). 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 has no practical meaning in terms of economy, transportation efficiency, combustion efficiency, etc. The polyether derivative and copolymer constituting the dispersant for coal-water slurry of the present invention can be produced by the following method. The polyether derivative () with a molecular weight of 5,000 to 100,000 of the present invention has the general formula A [(R ₁ O) _l (CH ₂ CH ₂ O) _n )
It is represented by H _o , and A is the residue of a reaction starting material having various functional groups having one or more active hydrogens in the molecule, and various alkylene oxides having 3 to 4 carbon atoms, such as propylene. oxide,
Butylene oxide is generally subjected to an addition reaction under pressure using a catalyst such as an alkali or acid, and then ethylene oxide is added in a similar manner. R ₁ is an alkylene oxide residue having 3 to 4 carbon atoms. l is 0 to 100 and represents the average number of added moles of alkylene oxide, and m is 50 to 1000 and is the average number of added moles of ethylene oxide. n is a number that is the same as or smaller than the functional number of the reaction starting material, and alkylene oxide may be bonded to all the functional numbers or only to a part of the functional numbers. One or more types of R ₁ O may be used, and the arrangement thereof may be either block type and/or random type. The active hydrogen group referred to here refers to an alcoholic hydroxyl group, a phenolic hydroxyl group, an amino group, a carboxylic acid group, etc., and is a starting material containing one or more of these groups. Specific examples of these are as follows. Alcohols containing one or more active hydrogen groups include ethyl alcohol, butyl alcohol, octyl alcohol, stearyl alcohol, ceryl alcohol, C12-14 secondary alcohol, (trade name: Softanol, manufactured by Nippon Shokubai Chemical Co., Ltd.), ethylene glycol, and polyethylene. Glycol, propylene glycol, polypropylene glycol, butylene glycol, polybutylene glycol, butanediol, pentanediol, glycerin, butanetriol, hexanetriol, trimethylolpropane, triethanolamine, diglycerin, pentaerythritol, sorbitan, sorbitol, glucose, Eurose, partially saponified polyvinyl acetate, cellulose, starch, etc. are useful. In addition, examples of amines containing one or more active hydrogen groups include dimethylamine, methylamine, ethylamine, propylamine, butylamine, allylamine, amylamine, octylamine, dodecylamine, laurylamine, tetradecylamine,
Octadecylamine, sebaceous alkylamine, coconut alkylamine, aniline, toluidine, nitroamine, benzylamine, chloraniline,
Cyclohexylamine, ammonia, tallow propylene diamine, ethylene diamine, tetramethylene diamine, phenylene diamine, benzidine,
Cyclohexyldiamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and the like are useful. Examples of carboxylic acids containing one or more active hydrogen groups include acetic acid, lauric acid, oleic acid, stearic acid, oxalic acid, malonic acid, phthalic acid, fumaric acid,
Various derivatives such as maleic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dimer acid, phenylene diacetic acid, hemimellitic acid, trimellitic acid, trimesic acid, pyromellitic acid, and ethylenediaminetetraacetic acid can also be used. Phenols containing one or more active hydrogen groups include phenol, bisphenol, cresol, alkylphenol, resorcinol, catechol, hydroquinone, and other compounds having aromatic hydroxyl groups are useful. Furthermore, those containing different types of active hydrogen groups in the same molecule, such as lactic acid, malic acid, glycolic acid, monoethanolamine, diethanolamine, amino acids, etc., can also be used. The copolymer of the present invention comprises polyalkylene glycol monoallyl ether (a), maleic acid monomer
Copolymers () derived from (b) and monomers copolymerizable with these (c) can be used, preferably with the general formula (However, in the formula, x and y are 0 or positive integers, and x + y
= 1 to 100, -(C ₂ H ₄ O-) unit and -(C ₃ H ₆ O-)
Units may be combined in any order. ) Polyalkylene glycol monoallyl ether (a) represented by the general formula (However, in the formula, R ₂ and R ₃ each represent hydrogen or a methyl group, and X and Y each represent -(C ₂ H ₄ O-) _p
-(C ₃ H ₆ O-) _q -R ₄ (R ₄ represents hydrogen or an alkyl group having 1 to 20 carbon atoms, p and q are 0 or a positive integer and p+q = 0 to 100, - (C ₂ H ₄ O−) units and -(C ₃ H ₆ O−) units may be bonded in any order), monovalent metals, divalent metals, ammonium groups, or organic amine groups. represents. ) is a copolymer () derived from a maleic acid monomer (b) and a monomer (c) copolymerizable with these. Polyalkylene glycol monoallyl ether
(A) can be synthesized by a known method of directly adding ethylene oxide and/or propylene oxide to allyl alcohol using an alkali such as KOH or NaOH as a catalyst. As long as it is represented by the above general formula, a single structure or a mixture can be used. The maleic acid monomer (b) is represented by the above general formula, and specifically includes maleic acid, fumaric acid, citraconic acid, mesaconic acid, and monovalent metal salts and divalent metal salts of these acids. salts, ammonium salts, organic amine salts, and these acids with HO−(C ₂ H ₄ O−) _p −(
C ₃ H ₆ O−) _q −R ₄ (However, R ₄ is hydrogen or has 1 to 1 carbon atoms
It represents 20 alkyl groups, p and q are 0 or positive integers, p+q=0 to 100, and -(C ₃ H ₆ O-) units and -(C ₂ H ₄ O-) units are They may be combined in such order. ) can be mentioned, and for example, secondary alcohol ethoxylate monomerate can be suitably used. Moreover, one or more types of these can be used. Monomers (c) copolymerizable with these include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, and Examples include esters obtained from these acids and alcohols (meth)acrylamide, vinyl acetate, propenyl acetate, aromatic vinyl compounds such as styrene and p-methylstyrene, vinyl chloride, etc. Or two or more types can be used. The copolymer () contains polyalkylene glycol monoallyl ether (a), a maleic acid monomer (b), and a monomer copolymerizable with these (c), each containing 24 to 24 to
75 mol%, 24 to 75 mol%, and 1 to 50 mol% (however, the total of components (a), (b), and (c) is 100 mol%). be. Coal with excellent performance by keeping this ratio range -
A dispersant for water slurry is obtained. In order to produce the 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, toluene, xylene, cyclohexane, n-
Examples include aromatic or aliphatic hydrocarbons such as 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 (), water and carbon atoms of 1
It is preferable to use at least one selected from the group consisting of lower alcohols of 1 to 4. Carbon number 1
Among the lower alcohols 4 to 4, 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. The copolymer () thus obtained may be used after being further neutralized with an alkaline substance, if necessary. Preferred examples of such alkaline substances include hydroxides, chlorides, and carbonates of monovalent metals and divalent metals, ammonia, organic amines, and the like. Moreover, the molecular weight of the copolymer () can be used in a wide range, but it is preferably in the range of 500 to 50,000. The dispersant for coal-water slurry of the present invention contains a polyether derivative () and a copolymer () as active ingredients, and the ratio of these two to be used is not particularly limited. ~50 parts by weight of copolymer (2)
A ratio of ~50 parts by weight (however, the total of both is 100 parts by weight) exhibits particularly excellent performance. 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. It is used in a proportion of 0.1 to 3% by weight (dry basis), preferably 0.3 to 2% by weight. In order to use the dispersant for coal-water slurry of the present invention, the polyether derivative () and the copolymer () may be mixed in advance and then added at the time of slurry preparation, or the polyether derivative ( ) and the copolymer () may be added separately at the time of slurry preparation. Alternatively, it may be mixed with coal in advance to form a slurry, or it may be dissolved in water in advance. Further, 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. 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, % means % by weight, and parts represent parts by weight. Preparation of Copolymer-1 Polyalkylene glycol monoallyl ether (containing an average of 5 ethylene oxide units per molecule) was placed in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, gas introduction tube, and reflux condenser. )
317.3 parts and 88.5 parts of water were charged, and the inside of the reaction vessel was purged with nitrogen while stirring, and heated to 95°C in a nitrogen atmosphere. Thereafter, an aqueous solution of 139.3 parts of maleic acid and 11.1 parts of ammonium persulfate dissolved in 209 parts of water and 6.2 parts of styrene were added in parallel over 120 minutes. After the addition was complete, 27.3 parts of a 20% aqueous ammonium persulfate solution was further added over 60 minutes. After completion of addition, 95℃ for 90 minutes
The temperature inside the reaction vessel was maintained to complete the polymerization reaction, and an aqueous copolymer solution was obtained. Next, 40% caustic soda aqueous solution was added to neutralize, and copolymer-1
An aqueous solution of was obtained. The pH and viscosity of this aqueous solution of copolymer-1 were as shown in Table-1. Preparation of Copolymer-2 Polyethylene glycol monoallyl ether (average 1
349 parts (containing 10 ethylene oxide units per molecule) and 64.7 parts of water were charged, the inside of the reaction vessel was purged with nitrogen while stirring, and heated to 65°C in a nitrogen atmosphere. Thereafter, an aqueous solution of 116 parts of maleic acid and 24.5 parts of ammonium persulfate dissolved in 174 parts of water, an aqueous solution of 11.2 parts of sodium bisulfite dissolved in 44.8 parts of water, and 25.8 parts of vinyl acetate were each added over 120 minutes. After the addition was completed, the temperature inside the reaction vessel was maintained at 65° C. for 120 minutes to complete the polymerization reaction, and an aqueous copolymer solution was obtained. Next, a 40% aqueous solution of caustic soda was added to neutralize the mixture to obtain an aqueous solution of copolymer-2. The pH and viscosity of this aqueous solution of copolymer-2 were as shown in Table-1. Preparation of Copolymer-3 Polyethylene glycol monoallyl ether (containing an average of 10 ethylene oxide units per molecule) was placed in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, gas introduction tube, and reflux condenser.
149.6 parts, polypropylene glycol monoallyl ether (containing an average of 5 propylene oxide units per molecule) 34.9 parts, maleic acid 58 parts,
171.8 parts of the mixture was added to a mixed solution consisting of 13 parts of hydroxyethyl methacrylate, 596 parts of isopropyl alcohol, and 7.7 parts of benzoyl peroxide, and the inside of the reaction vessel was purged with nitrogen while stirring, and heated to the boiling point of the mixed solution in a nitrogen atmosphere. . Thereafter, 687.4 parts of the remaining mixed solution was added over 120 minutes. After the addition was completed, the temperature in the reaction vessel was maintained at the boiling point for 120 minutes to continue the polymerization reaction. After that, the temperature inside the reaction vessel was returned to room temperature, and the benzoyl peroxide 7.7
The mixture was heated again to distill off isopropyl alcohol, and neutralized by adding deionized water and a 40% aqueous solution of caustic soda to obtain an aqueous solution of copolymer-3. The pH and viscosity of this aqueous solution of copolymer-3 were as shown in Table-1. Preparation of Copolymer-4 Polyalkylene glycol monoallyl ether (average of 3 ethylene oxide units and 2 units per molecule (containing propylene oxide units) 220.6 parts, 3 moles of secondary alcohol ethoxylate (Softanol-30, manufactured by Nippon Shokubai Chemical Co., Ltd.) monomaleate
344.3 parts of styrene, 8.3 parts of styrene, 241.4 parts of isopropyl alcohol, and 16.9 parts of benzoyl peroxide were charged with 246.5 parts of the mixed solution, and the inside of the reaction vessel was replaced with nitrogen while stirring, and heated to the boiling point of the mixed solution in a nitrogen atmosphere. . Then the remaining mixed solution
575 parts were added in 120 minutes. After the addition was completed, the temperature in the reaction vessel was maintained at the boiling point for 120 minutes to complete the polymerization reaction. Thereafter, the temperature inside the reaction vessel was returned to room temperature, 16.9 parts of benzoyl peroxide was added and heated again, and the isopropyl alcohol was distilled off to obtain a copolymer. Next, 40% caustic soda aqueous solution and deionized water were added to neutralize the copolymer.
An aqueous solution of No. 4 was obtained. The pH and viscosity of this aqueous solution of copolymer-4 were as shown in Table-1.

[Table]
Example Aqueous solution containing predetermined amounts of various dispersants shown in Table 2
Add 68.3 g of Daido charcoal (moisture content 5.1%), which has been ground to 31.7 g so that 79% passes through a 200 mesh sieve, little by little at room temperature while stirring. After adding the entire amount, use a homo mixer (manufactured by Tokushu Kikako).
A coal-water slurry was prepared by stirring at 10,000 RPM for 2 minutes, and the viscosity was measured at 25°C to evaluate the fluidity. The results are shown in Table 2. Low viscosity indicates good fluidity.

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【table】

Claims (1)

[Claims] 1 (A) General formula A [(R ₁ O) _l (CH ₂ CH ₂ O) _n ) H) _o (wherein A is an alcohol having one or more active hydrogens in the molecule) , residues of phenols, amines, carboxylic acids and their derivatives, R ₁
is an alkylene oxide residue having 3 to 4 carbon atoms, l
is the average number of added moles of ethylene oxide (0 to 100), m is the average number of added moles of ethylene oxide (50 to 1000, n is the number of functional groups), and (B) It is characterized by containing a polyalkylene glycol monoallyl ether (a), a maleic acid monomer (b), and a copolymer derived from a monomer (c) copolymerizable with these (c). Dispersant for coal-water slurry.