JPS59189194A - Viscosity depressant for concentrated coal/water slurry - Google Patents

Abstract

PURPOSE:To provide a viscosity depressant which reduces the viscosity to a marked extent even when added in a small amount and produces a coal/water slurry which can be pumped in a high concentration, prepared by adding a low- molecular nionionic surfactant to a polyether compd. or liked polyether compd. CONSTITUTION:The viscosity depressant is prepared by adding a low molecular nonionic surfactant having a molecular weight of below 1,000, preferably below 800, to a polyether compd. obtained by adding alkylene oxide to a compd. having at least three, preferably at least five active hydrogen atoms or a linked polyether compd. obtained by linking at least two molecules of the above polyether compd. with a linking agent. The polyether compd. or linked polyether compd. has a molecular weight of 16,000-300,000. It reduces the viscosity of coal/water slurry, improves its fluidity and makes pumping of concentrated coal/ water slurry possible.

Description

[Detailed description of the invention] The present invention relates to a thinner for coal-water slurries.

In recent years, due to the depletion of oil resources, the use of coal has been reconsidered.
Various ways of using it are being considered. However, unlike oil, coal is a solid and cannot be transported by pump. For this reason, various methods are being considered for pulverizing coal and dispersing it in water to form a water slurry. However, with current technology, this method becomes difficult to transport by pumping as the coal becomes thicker and loses fluidity as the coal concentration increases.

On the other hand, lowering the coal concentration reduces transportation efficiency and requires a dehydration process before combustion, which is expensive and impractical.

JP-A-54-33803 describes adding a combination of a polymeric surfactant and a low-molecular surfactant to a finely divided ore slurry, and specifically, polyacrylamide is used as a nonionic polymeric surfactant. , hydroxyethyl cellulose, polyethylene oxide, and guar gum are exemplified, but all of them are intended for low-concentration fine ore slurry, have poor viscosity-reducing effects, and are difficult to obtain high-concentration slurry.

In order to improve the above-mentioned drawbacks, the present inventors have already discovered that polyether compounds (or bonded polyether compounds) have excellent effects as thinners for highly concentrated coal-water slurries, and have filed a patent application. However, as a result of thinking that it might be possible to obtain a more superior high-concentration coal-water slurry thinner, we found that polyether compounds, which are still mainly composed of bonded polyether compounds, have no viscosity-thinning effect on their own. We have discovered that a product containing a specific low-molecular-weight nonionic surfactant exhibits an excellent effect as a thinning agent for high-concentration coal-water slurry IJ, and has come to provide the present invention. .

That is, it is a highly concentrated coal-water slurry thinner used to reduce the viscosity of the coal-water slurry and improve its fluidity and stability, and [a] contains 3 or more active hydrogen atoms in the molecule, preferably A polyether compound obtained by adding an alkylene oxide to a compound containing 5 or more or 2 of the above polyether compounds
A bonded polyether compound in which more than one molecule is bonded with a binder, and a polyether compound with a molecular weight of 16,000 to 300,000 or a low molecular weight of less than 1,000, preferably 800 or less. This is a thinning agent for coal-water slurry characterized by containing a nonionic surfactant.

Coal used in the coal-water slurry of the present invention includes anthracite, bituminous coal, sub-bituminous coal, lignite, and cleaned versions thereof, but any coal may be used. In addition, the particle size of the coal in the water slurry may be any particle size as long as it is powder, but since the pulverized coal currently burned in thermal power plants is more than 200 mesh This is a guideline for the particle size of charcoal.

However, the thinner of the present invention is not affected by particle size, and exhibits excellent effects on coal powder of any particle size.

Cleaned coal is coal from which inorganic substances such as ash and sulfur have been removed. As a method for cleaning coal, for example, Oll Agglome
ration method (hereinafter referred to as OA method), flotation method, heavy liquid separation method, etc. However, methods other than these may also be used and are not particularly limited.

Regarding the OA method, after dry or wet pulverization of coal, a water slurry is prepared, and an appropriate amount of oil with a surfactant added if necessary is added, or after the coal is coated with the above oil in advance, a water slurry is prepared. By adjusting and stirring, the difference in wettability between the organic and inorganic components of the coal with respect to oil and water is utilized to selectively wet the organic components of the coal.The oil is used as a binder to cause agglomeration of the organic components of the coal. . On the other hand, inorganic substances have a weak affinity with oil and are liberated in water.
This is a method that can remove inorganic substances at the same time by separating water from coagulated coal. The coal concentration in the coal-water slurry of the OA method is usually 10 to 65% by weight.

The oil used in the OA method is crude oil or various fractions obtained from crude oil, such as kerosene, light oil, A heavy oil, Bv oil, C heavy oil, etc., tar or shale oil, ethylene cracked residue, or various blended oils, and is generally used as a fuel. These are mineral oils used as oils, lubricating oils, and cleaning oils. Water-insoluble oils such as benzene, toluene, xylene, and animal and vegetable oils may also be used, but among these, heavy oils such as C heavy oil and tar residue oil are particularly preferred because they are inexpensive. It is generally sufficient to use this oil in an amount of 30% by weight or less based on the coal in the coal-water slurry to be treated for mineral removal.

In addition, the flotation coal washing method is an existing coal washing method in which a very small amount of oil is added to the pulverized coal-water slurry and stirred to create foam.
Generate floss. Similar to the OA method, in this method, the organic components of the coal adhere to the cross oil film, or the inorganic materials are liberated in the water.
This is a method that can separate coal organic components.

The oils used in the flotation coal flotation method are terpineol, tar, A heavy oil, C heavy oil, light oil, and kerosene.Usually, several tens of weight percent or more of inorganic substances are removed from coal by the above method.

If the coal cleaned in this way is used, the effect of the additive of the present invention is significantly superior to that of uncleaned coal, and a coal-water slurry with several points higher concentration can be obtained. In addition to this effect, when cleaned coal is used, there are other significant benefits such as suppressing boiler corrosion during combustion and reducing negative phase effects on ash removal equipment and desulfurization equipment.

Next, as the thinner used in the coal-water slurry of the present invention, [al] a polyether compound obtained by adding an alkylene oxide to a compound containing three or more active hydrogen atoms in the molecule; A bonded polyether compound in which more than one molecule is bonded with a binder, and the molecular weight of the polyether compound or bonded polyether compound is 16J]
000,000 to 300,000, and those containing a low-molecular nonionic surfactant with a molecular weight of less than 1,000, preferably 800 or less as an essential component.

[a] In the acid component, examples of compounds containing three or more active hydrogen atoms in the molecule include alcohols, amines,
Examples include carboxylic acids, polyalkylene imines, and aliphatic aldehyde condensates of aromatic compounds containing phenolic active hydrogen.

Alcohols include those containing 3 active hydrogens,
For example, glycerin, butanetriol, trimethylolpropane, triethanolamine, etc., containing 4 active hydrogen atoms, diglycerin, pentaerythritol, sorbitol, etc., containing 5 or more active hydrogen atoms, such as xylitol, sorbitol, glucose, sulfate, etc. Derivatives such as alcohol, partially saponified polyvinyl acetate, partially saponified polyvinyl acetate copolymer, cellulose, starch, etc., and partially esterified alcohols containing 4 or more active hydrogens, Examples include those containing three or more active hydrogens.

Examples of amines include those containing three active hydrogen atoms, such as ammonia and tallow propylene diamine, and those containing four active hydrogen atoms, such as ethylenediamine, tetramethylene diamine, hexamethylene diamine, phenylene diamine, benzidine, Cyclohexyl diamines, those containing 5 or more active hydrogens, such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, etc., and partial amides of amines that still contain 4 or more active hydrogens. Examples include various derivatives such as those containing three or more active hydrogen atoms. Examples of carboxylic acids include those containing three active hydrogen atoms, such as hemimellitic acid and trimellitic acid, and those containing four active hydrogen atoms, such as butanetetracarboxylic acid, pyromellitic acid, and ethylenediaminetetraacetic acid. those containing 5 or more;
For example, acrylic acid polymers, acrylic acid copolymers, methacrylic acid polymers, methacrylic acid copolymers, maleic anhydride polymers, maleic anhydride copolymers, polymers and copolymers of acrylic esters and methacrylic esters. Examples include partially saponified products of , anhydrides and acid halides of the above acids.

As polyalkyleneimines (d1 polyethyleneimine, polypropyleneimine, and 3 active hydrogens obtained by addition polymerizing ethyleneimine or propyleneimine to substances containing one or more active hydrogens such as alcohols, phenols, amines, and carboxylic acids) Examples include those containing the above, and those obtained by ammonosis or aminososis of dihalogenoalkane.

Furthermore, various derivatives containing three or more active hydrogen atoms obtained from polyalkylene imines, which have excellent chemical reactivity similar to ordinary amines, can also be mentioned. Representative examples of various derivatives are shown below.

(a) Reaction products with aldehydes and ketones.

(b) Reaction product with alkyl halide.

(C+ Reaction product with isocyanates and thioisocyanates.

(d) A reaction product with a substance having an active double bond.

(el Epoxy compound, reaction product with shrimp halohydrins.

(f) Reaction products with cyacamides, guanidines, urea, etc.

(g) Reaction products with carboxylic acids, acid anhydrides, acyl halides, etc.

Examples of aliphatic aldehyde condensates of aromatic compounds containing phenolic active hydrogen include [1] phenol, cresol, xylenol, butylphenol,
Phenols and substituted phenols such as nonylphenol, aminephenol, and hydroxybenzoic acid; (2) naphthols and substituted naphthols such as naphthol, methylnaphthol, butylnaphthol, and octylnaphthol; (3) polyhydric phenols such as catechol, resorcinol, and pyrogallol. (4) polyhydric naphthols such as naphtresorcin and a-naphthohydroquinone, (5) condensed phenols such as bisphenol A1 and bisphenol S, and aliphatic aldehydes and aromatic compounds containing phenolic active hydrogen. Examples include those containing three or more condensed active hydrogens.

Examples of aliphatic aldehydes include formalin, acetaldehyde, and glyoxal, with formalin being the most common.

When condensing aliphatic aldehydes, the aromatic compound containing phenolic active hydrogen and the aliphatic aldehyde may be condensed first, and then alkylene oxide may be added to the aromatic compound containing phenolic active hydrogen. The alkylene oxide may be added first, and then the aliphatic aldehyde may be condensed, but the former is common.

However, it is not limited to a specific method,
Any method can be used as long as the desired polyether compound can be obtained.

As a compound containing three or more active hydrogens in the molecule,
Although the above-mentioned ones can be mentioned, the number of active hydrogens contained is preferably 5 or more.

When a compound containing a large number of active hydrogens is used, a compound with a complex three-dimensional structure can be obtained by addition of an alkylene oxide, so that even more excellent effects are exhibited.

Examples of the alkylene oxide to be added to a compound containing three or more active hydrogen atoms in the molecule include ethylene oxide, propylene oxide, and butylene oxide, each of which may be added singly or in combination. When two or more types are added, the arrangement may be block copolymerization, random copolymerization, or whichever one is added first, but in order to effectively exhibit surface activity, block copolymerization is preferred. is even more preferable. The alkylene oxide contains at least ethylene oxide, and the content of ethylene oxide is 10 to 100% by weight of the total alkylene oxide.
, preferably 30 to 95% by weight.

Examples of the polyether compound include those having a molecular weight of 16,000 to 300,000, which are obtained by adding alkylene oxide to a compound containing three or more active hydrogen atoms in the molecule according to a known method.

Examples of binders for polyether compounds include polyvalent incyanate compounds, polyvalent epoxy compounds, polyvalent carboxylic acids or polyvalent carboxylic acid derivatives, peroxides (radical generating catalysts), and formalin.

Examples of polyvalent incyanate compounds include hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, 1.5 naphthylene diisocyanate, 4.4' diphenylmethane diisocyanate, etc., and polyvalent epoxy compounds include: Examples include diglycidyl bisphenol A1, diglycidyl ethylene glycol, and diglycidyl tetraoxyethylene glycol.

Examples of polyvalent carboxylic acids or polyvalent carboxylic acid derivatives include carboxylic acids containing two active hydrogen atoms, such as oxalic acid, malonic acid, phthalic acid, maleic acid, glutaric acid, adipic acid, azelaic acid, cepatic acid, and dodecanionic acid. , dimer acid, 0-phenylenediacetic acid, etc., carboxylic acids containing 3 active hydrogens, such as hemimellitic acid, trimellitic acid, carboxylic acids containing 4 active hydrogens, such as butanetetracarboxylic acid, pyromellitic acid, ethylenediamine Carboxylic acids containing 5 or more active hydrogen atoms such as tetraacetic acid, such as acrylic acid polymers, acrylic acid copolymers, methacrylic acid polymers, methacrylic acid copolymers, maleic anhydride polymers, maleic anhydride copolymers , partially saponified polymers and copolymers of acrylic esters and methacrylic esters, and anhydrides and acid halides of the above acids.

Peroxides (radical generation catalysts) include hydrogen peroxide,
Examples include benzoyl peroxide (benzoyl peroxide), di-tert-butyl peroxide, cumene oxide, and dicumyl peroxide.

Also effective are those bound by reaction with formalin under acidic conditions.

When bonding is performed using a polyvalent isocyanate compound or a polyvalent epoxy compound as a binder, the proportion of the binder used is arbitrary, but generally it is 0.05 to 5% relative to the terminal hydroxyl group equivalent of the polyether compound. equivalent, preferably from 0.1 to
Use 3 equivalents.

The bonding conditions include mixing the polyether compound and the binder and heating the mixture at 40 to 150°C, preferably at 50 to 120°C, while stirring.
Heating is carried out in the range of 0.degree. C., and if necessary, an acid or base catalyst commonly used for bonding can be used.

When bonding is performed using a polyvalent carboxylic acid or a polyvalent carboxylic acid derivative as a binder, the proportion of the binder used is arbitrary, but generally it is 0.05 to 0.05 to the equivalent of the terminal hydroxyl group of the polyether. 5 equivalents, preferably 0.1 to 3 equivalents are used.

When using a polyhydric carboxylic acid, the bonding conditions include the polyether compound and the binder at 60 to 250°C under reduced pressure in the presence or absence of an inert solvent as necessary.
The purpose can be easily achieved by heating and dehydrating at a temperature in the range of 80 to 220°C. in this case,
Conventional esterification catalysts can be used to facilitate the reaction.

In addition, when using a polyhydric carboxylic acid halide, the polyether compound and the binder are mixed in the presence or absence of an inert solvent, and an inert gas is passed therethrough to facilitate dehydrogenation. Or at -10 to 150°C using a known agent that can easily capture the generated hydrogen halide.
The purpose can be easily achieved by carrying out the reaction, preferably at a temperature in the range of 0 to 120°C.

When bonding is performed using peroxide as a binder, the proportion of the binder (radical generating catalyst) used is from 0.05% to 10% by weight, preferably from 0.1% by weight to the polyether compound. Any amount up to 5% by weight can be used.

For example, Journal
of Applied Polymer 5cien
ce Vo171r11) 461-468 (1963
), etc., and these known techniques can be directly applied to the connection referred to in the present invention. Generally, a predetermined amount of binder is mixed with a polyether compound in the presence or absence of a solvent, and the mixture is heated to 50 to 250°C, preferably 70°C.
The reaction is carried out in the range of 0 to 180°C, and the solvent is distilled off if necessary to obtain the target substance.

When binding using formalin as a binding agent, known techniques can be used, but generally it is carried out as follows.

That is, 0.1 to 10 equivalents of formalin, preferably 0.5 to 5 equivalents are used, and 0.05 to 0.05 oos equivalent of an acidic catalyst is added to 60 to 10 equivalents of formalin per equivalent of polyether compound.
The temperature was raised to 100°C, stirred for 1 to 3 hours, and then heated to 100°C.
The reaction is completed by raising the temperature to 0-180°C.

As mentioned above, the bonded polyether compound is a bonded polyether compound in which two or more molecules of a polyether compound in which alkylene oxide is added to a compound containing three or more active hydrogen atoms in the molecule are bonded with a binder. and those having a molecular weight of 16,000 to 300,000.

The bound polyether compound has a linear or network structure, or a mixture of both.

In component (1), low-molecular nonionic surfactants with a molecular weight of less than 1ρ00, preferably 800 or less, include compounds containing one or more active hydrogen atoms in the molecule, such as alcohols, amines, carboxylic acids, polyesters, etc. Alkylene imines, aromatic compounds containing phenolic active hydrogen, their aliphatic aldehyde condensates, etc. with alkylene oxides added, polyhydric alcohol aliphatic esters, fatty acid alkanolamides, or their alkylene oxide adducts, etc. can give.

As alcohols, those containing one active hydrogen,
For example, octyl alcohol, lauryl alcohol, oleyl alcohol, those containing two active hydrogens, such as ethylene glycol, polyethylene glycol, propylene gelol, polypropylene glycol, butylene glycol, holifthylene glycol, butanediol, bentanediol, Examples include those containing three or more active hydrogen atoms, such as those mentioned above, such as hexanediol.

Examples of amines include those containing one active hydrogen, such as dimethylamine, N-methyllaurylamine, etc.
Those containing two active hydrogen atoms, such as methylamine, propylamine, allylamine, octylamine, laurylamine, pentadecylamine, tallow alkylamine,
Ama IJ y, P-also 1rJ:, M-toluidine,
Examples include those containing three or more active hydrogens, such as benzylamine and cyclohexylamine, such as those listed above.

As carboxylic acids, those containing one active hydrogen,
For example, acetic acid, octylic acid, lauric acid, sularic acid, oleic acid, benzoic acid, P-nitrobenzoic acid, etc. Containing two active hydrogen atoms For example, oxalic acid, malonic acid, phthalic acid, areic acid, glutaric acid , adipic acid, azelaic acid, sepatic acid, dimer acid, etc., active hydrogen 3
Examples include those containing more than one of these, such as those listed above.

Polyalkyleneimines include polyethyleneimine, polypropyleneimine, or those containing one or more of the above active hydrogens, and ethyleneimine, globyleneimine, etc. added thereto. Examples include those obtained by amithrisis or amithrisis of halogenoalkanes.

Furthermore, similar to the above, various derivatives containing one or more active hydrogens obtained from polyalkylene imine may also be mentioned.

Examples of aromatic compounds containing phenolic active hydrogen include the above (1), (2), (3), (4), and (
Examples include aromatic compounds containing phenolic active hydrogen (5).

Examples of the aliphatic aldehyde condensate include aromatic compounds containing phenolic active hydrogen of the above +1+, (2), (3), (4) and (5) and aliphatic aldehydes such as formalin, acetaldehyde, Examples include condensed products such as glyoxal.

Examples of the polyhydric alcohol fatty acid ester include those obtained by subjecting a polyhydric alcohol and a fatty acid ester to an esterification reaction or transesterification reaction.

Examples of polyhydric alcohols include jetanolamine,
Examples include glycerin, pentaerythritol, sorbitol, nrubitan, and sucrose.

Examples of fatty acids include saturated or unsaturated fatty acids having 2 to 22 carbon atoms, such as acetic acid, propionic acid, caproic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and erucic acid.

Examples of fatty acid esters include methyl esters or ethyl esters of the above-mentioned fatty acids, and mixed fatty acid esters such as coconut oil or beef tallow.

Examples of fatty acid alkanolamides include those obtained by a condensation reaction between alkanolamines and fatty acids.

Examples of the alkanolamine include monoethanolamine and jetanolamine.

Examples of fatty acids include those listed above.

Examples of alkylene oxides added to compounds containing one or more active hydrogen atoms in the molecule include ethylene oxide, propylene oxide, butylene oxide, etc.
Each of them may be used alone or in combination of two or more. When two or more types are added, the arrangement may be block copolymerization, random copolymerization, or whichever one is added first. The alkylene oxide contains at least ethylene oxide, and the content of ethylene oxide is from 10 to 100% by weight of the total alkylene oxide. The low-molecular nonionic surfactant obtained in this way has a molecular weight of 1. (X) less than 0, preferably 800 or less.

Next, the blending ratio of [al component and [b] acid component is expressed as a weight ratio (
al component 20-79, [b] component 80-21 theal.

As described above, the present invention uses a polyether compound or a bonded polyether compound having a specific molecular weight and a nonionic surfactant having a specific molecular weight as a thinning agent for coal-water slurry.

The amount of the thinner of the present invention added is 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight, based on the coal-water slurry.
It is 0% by weight, and excellent effects are exhibited with this added amount. The fluidity limit of a coal-water slurry varies depending on the type and particle size of the coal, but generally, if a thinner is not added, the fluidity will be lost at a coal concentration of around 50% by weight, but the thinner of the present invention Since the viscosity decreases significantly when the coal is added, it has fluidity even when the coal concentration is 61% by weight or more, especially 70% by weight or more. When cleaner coal is used, the coal concentration increases by several points, typically 3 to 10 points.

The thinner of the present invention can also be used in combination with other surfactants. Regarding the method for producing coal-water slurry and the method for adding a thinner, there are two methods: dry pulverizing coal in advance and then mixing a thinner into an aqueous solution, or adding a thinner after making a coal-water slurry. A method of adding coal, water, and a thinner to the mill and mixing it while crushing the coal, and a method of mixing using cleaned coal instead of coal in each method. Any method can be implemented.

The reason why the thinner of the present invention exhibits an excellent effect is that the high molecular weight polyether compound or bonded polyether compound, that is, the nonionic surfactant and the low molecular weight nonionic surfactant, are bonded to each other, forming a bond on the particle surface. After dense and strong adsorption, many ether bonds hydrate the surrounding water and transform this water into a structure that acts like oil, making the coal particles stable as primary particles and having good fluidity. It is expected that this will improve. At the same time, a significant decrease in hardness occurs.

In addition, if you use clean coal that has been deashed, the effect will further increase.During deashing, the ash, which is highly hydrophilic and has fine particles with a large surface area, is removed, improving organic properties. This is because the thinning agent of the present invention effectively acts on the coal surface, thereby increasing the coal concentration.

The thinning agent of the present invention has a particularly excellent effect of stably dispersing coal in water, and maintains a homogeneous coal-water slurry without causing water separation even after a long period of time, for example, one month or more. ing.

In this way, the thinner of the present invention can be used in an amount of 0.01 to 5.0% by weight, preferably 0.03 to 5.0% by weight, based on the coal-water slurry.
By simply adding 2.0 weight 9-4, the viscosity of the coal-water slurry can be significantly reduced and a coal-water slurry that can be pumped at a high concentration can be made.

Examples are shown below. In the examples, the values are based on weight.

Example 1 Into an aqueous solution containing a predetermined amount of the thinner shown in Table 1,
Coal pulverized to 0 mesh and 80 chips is stirred at room temperature and added from 10,000 to 10,000 to prepare a coal-water slurry of a predetermined concentration. The viscosity of this slurry is measured at 25°C and the fluidity is observed.

Furthermore, this slurry was poured into a 500ml cylinder for 1 hour, and after leaving it for 2 months, the upper layer (1 hour from the top)
c+n), measure the coal concentration in the lower layer (1 cm from the bottom).

The test results are shown in Table 2. As shown in Table 2, when the thinner of the present invention is added, the viscosity is 1,000 to 2,800 CI) even at a coal concentration of 74 to 77 cm, and the fluidity is extremely good. In addition, even after the slurry was allowed to stand for two months, there was almost no sedimentation of the coal, and it remained very stable. On the other hand, if a general anionic surfactant is added, a low-molecular nonionic surfactant is added alone, or no viscosity reducing agent is added, the viscosity will increase to 20,000 cp or more at a coal concentration of 50 cm. No, it doesn't flow at all.

Example 2 A clean coal-water slurry of a predetermined concentration is prepared in the same manner as in Example 1 using cleaned coal. The coal particle size is 200 mesh and 80 coefficient pass. The viscosity of this slurry is measured at 25° C., and its fluidity is also observed.

After this slurry was allowed to stand for two months, the coal concentrations in the upper and lower layers were measured in the same manner as in Example 1.

The thinners of the present invention used in the test are shown in Table 1. The test results are shown in Table 3.

As shown in Table 3, when the thinner of the present invention is added to the Sifreen fossilized coal-water slurry, the viscosity is 1β00 to 2,600 cp even when the coal concentration is 78 to 80 cm, and the viscosity is extremely low and the fluidity is good. . In addition, the slurry is very stable with almost no coal settling even after it has been allowed to stand for two months. On the other hand, if a general anionic surfactant is added, a low-molecular nonionic surfactant is added alone, or no thinner is added, the viscosity will be higher than zo, ooocp at a coal concentration of 50 cm. Tonashi, it doesn't flow at all.

Claims (1)

[Scope of Claims] +1) A thinning agent for highly concentrated coal-water slurry used to reduce the viscosity of coal-water slurry and improve fluidity and stability, comprising [aJ 3 active hydrogen in the molecule] A polyelder compound obtained by adding an alkylene oxide to a compound containing 5 or more, preferably 5 or more, or 2 of the above polyether compounds
A bonded polyether compound in which more than one molecule is bonded with a binder, and the size of the polyether compound or the molecular weight of the bonded polyether compound is 16,000 to 300,000; A thinning agent for coal-water slurry, characterized by containing an ionic surfactant. (2: The polyether compound folded or bonded polyether compound contains ethylene oxide, and the content thereof is 10 to 100% of the total alkylene oxide, preferably 3%
The thinning agent for coal-water slurry according to claim m, which has a weight coefficient of 0 to 95. +3] [a] The blending ratio of the four acid components is [
a) Components 20 to 79, [1:l] Component k -2-1 A thinning agent for coal-water slurry according to claim 1 or 1). (4) The coal-water slurry according to any one of claims (1) to (3) for use in a coal-water slurry having a coal concentration of 61 N or more, preferably on a 70-weight plate. Thinning agent for use. (5) The thinner for coal-water slurry according to any one of claims ft) to (4), wherein the coal is cleaned coal.