JPH0149193B2 - - 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 has been pulverized into powder, which is then made into a coal-water slurry, which is then fluidized and transported through a 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 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 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 attempting to increase the concentration of coal powder using known techniques, the slurry becomes significantly thickened and loses fluidity. Conversely, if the concentration of coal powder in water is reduced,
Transportation efficiency, combustion efficiency, etc. are reduced, and when a water slurry of coal is used after being dehydrated, the dehydration and drying processes also have problems such as extra costs and 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 continued to conduct intensive research in order to solve the above-mentioned problems in dispersants for coal-water slurries, and have found that a certain polyether derivative (),
The present invention was completed based on the discovery that a composition containing the copolymer () and the compound () has an excellent effect as a dispersant for coal-water slurry. 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 (A) general formula A [(R ₁ O) _l (CH ₂ CH ₂ O) _n H _] Residues of alcohols, phenols, amines, carboxylic acids and derivatives thereof having R _{1 or} more
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 has a molecular weight of 5000 to 100,000 () (B) Polyalkylene Copolymers derived from glycol monoallyl ether (a) maleic acid monomers (b) and monomers copolymerizable with these (c)
and (C) one or more compounds selected from the group consisting of polyalkylene imine and polyalkylene imine derivatives. 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 (), copolymer (), and compound () constituting the dispersant for coal-water slurry of the present invention can be produced by the following method. The polyether derivative () having 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 H]
_o , where A is a 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. Generally, butylene oxide is subjected to an addition reaction under pressure using a catalyst such as an alkali or acid, and then ethylene oxide is added in the same 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. Further, a polyether derivative in which the sum of the number of carbon atoms in R ₁ times (l×n) and the number of carbon atoms in A is 10 to 800 can be suitably used. 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, tallow 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 is a copolymer derived from polyalkylene glycol monoallyl ether (a), a maleic acid monomer (b), and a monomer copolymerizable with these (c). ) can be used, preferably 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. ) This is a copolymer () derived from the maleic acid monomer (b) shown in (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 any order. ) can be mentioned, and for example, secondary alcohol ethoxylate monomerate can be suitably used. One or more of these can be used. Monomers (c) that can be copolymerized with these include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids. and 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. A species or two or more species can be used. The copolymer () contains 24% each of a polyalkylene glycol monoallyl ether (a), a maleic acid monomer (b), and a monomer that can be copolymerized with these (c).
-75 mol%, 24-75 mol% and 1-50 mol% (however, the total of components (a), (b) and (c) is 100 mol%). It is. 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 polyalkylene imine and polyalkylene imine derivative of the compound () constituting the dispersant for coal-water slurry of the present invention can be produced by the method shown below. The polyalkyleneimine of the present invention has at least one
It is a homopolymer or copolymer consisting of various alkyleneimine monomers. The alkyleneimine monomers are 1,2-alkyleneimine (aziridine) and 1,3-alkyleneimine (azetidine), and specific examples thereof include ethyleneimine,
1,2-propyleneimine, 1,3-propyleneimine, 1-methylaziridine, 2,2-dimethylaziridine, 1-ethylaziridine, 2-ethylaziridine, 2-n-propylaziridine, 2
-isopropylaziridine, 2-n-butylaziridine, 2-isobutylaziridine, 1-(2-
aminoethyl)aziridine, 1-(2-cyanoethyl)aziridine, 1-(2-hydroxyethyl)
Examples include aziridine. Homopolymerization and copolymerization of alkyleneimine monomers to polyalkyleneimines are promoted with acid catalysts and are easily carried out by methods known per se.
The form of copolymerization of the alkyleneimine monomer may be any of random copolymerization, block copolymerization, graft copolymerization, and the like. Typical polyalkylene imines used in the present invention are polyalkylene imines and polypropylene imines, which are produced on an industrial scale and are readily available commercially.
Another preferred polyalkyleneimine is poly(ethyleneimine-propyleneimine) copolymer. The molecular weight of the polyalkyleneimine is not particularly limited, and a wide range of 600 to 1,000,000 is usually used, but a range of 5,000 to 200,000 is particularly preferred. Polyalkylene imine derivatives are so-called modified polyalkylene derivatives made by reacting some of the amino groups of polyalkylene imine with a compound having a functional group that is reactive with amino groups, and making them soluble in water or a solvent mainly composed of water. It means imine. Specific examples of such polyalkylene imine derivatives include polyalkylene imine derivatives obtained by reacting a compound having an active double bond such as acrylamide or acrylonitrile; and polyalkylene imine derivatives obtained by reacting an epoxide compound such as ethylene oxide, glycidol or epichlorohydrin. Polyalkyleneimine derivatives obtained by reacting aldehydes such as formaldehyde or acetaldehyde; Polyalkyleneimine derivatives obtained by reacting acid anhydrides such as succinic anhydride, etc. , of course, it is not limited to these.
One type of polyalkyleneimine derivative may be used alone, or two or more types may be used in combination. It can also be used in combination with polyalkyleneimine. The dispersant for coal-water slurry of the present invention contains a polyether derivative (), a copolymer (), and a compound () as active ingredients,
Although the ratio of these used is not particularly limited, a ratio of polyether derivative ()/copolymer ()/compound (); 20 to 95% by weight/3 to 50% by weight/2 to 30% by weight provides particularly excellent performance. demonstrate. 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. 0.05-3% by weight (dry basis), preferably 0.1-2
It is used in a proportion of % by weight. To use the dispersant for coal-water slurry of the present invention, polyether derivatives (), copolymers ()
and compound () may be mixed in advance and then added during slurry preparation, or polyether derivative (), copolymer () and compound () may be added separately during 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 with reference to comparative examples and examples, but of course the present invention is not limited thereto. In addition, unless otherwise specified in the examples, % is weight %.
, and parts represent parts by weight. Preparation of Copolymer-1 Polyethylene 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 anhydride 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, 90
The temperature inside the reaction vessel was maintained at 95° C. for a minute to complete the polymerization reaction, and an aqueous copolymer solution was obtained. Next, a 40% aqueous solution of caustic soda was added to perform neutralization, thereby obtaining an aqueous solution of copolymer-1. 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 a mixed solution consisting of 13 parts of hydroxyethyl methacrylate, 596 parts of isopropyl alcohol, and 7.7 parts of benzoyl peroxide were charged, 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. . 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) was placed in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, gas inlet tube, and reflux condenser. 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, and 246.5 parts of the mixed solution consisting of 344.3 parts of styrene, 8.3 parts of isopropyl alcohol, and 16.9 parts of benzoyl peroxide were charged, 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 continue 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 are 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 crushed to 79% through a 200 mesh sieve, to 31.7 g at room temperature while stirring little by little. After adding the entire amount, use a homo mixer (manufactured by Tokushu Kikako).
The 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. The substances of compound () shown in Table 2 are as follows. -1; Polyethyleneimine (molecular weight approximately 70,000) -2; Polypropyleneimine (molecular weight approximately 20,000) -3; Ethyleneimine (2.5 mol)/1.2-propylene imine (1.0 mol) copolymer (molecular weight approximately 40,000) - 4; Acrylonitrile addition (0.1 mol) polyethyleneimine (molecular weight approximately 50,000)

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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
(B) Polyether derivative () with a molecular weight of 5,000 to 100,000, represented by Copolymers derived from alkylene glycol monoallyl ether (a), maleic acid monomers (b), and monomers copolymerizable with these (c), and (C) polyalkyleneimine and polyalkylene 1. A dispersant for coal-water slurry, comprising one or more compounds selected from the group consisting of imine derivatives. 2 In the polyether derivative (), the sum of (l x n) times the number of carbon atoms in R ₁ and the number of carbon atoms in A is 10 to
800, the dispersant according to claim 1. 3. The dispersant according to any one of claims 1 to 2, wherein the polyalkylene imine is polyethylene imine or polypropylene imine. 4. The dispersant according to claim 1, wherein the polyalkylene imine or polyalkylene imine derivative has an average molecular weight of 5,000 to 200,000.