JPH0216957B2 - - 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 to be 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 because 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. 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 water is reduced, transportation efficiency, combustion efficiency, etc. will decrease, and if the coal water slurry is dehydrated and used, dehydration,
The drying process also has problems, such as being expensive and causing pollution problems. Conventionally, various dispersants for coal-water slurries have been proposed to solve these problems. For example, sodium olefinate, sodium dodecylbenzenesulfonate, alkylarylsulfonate,
polyoxyethylene alkyl phenyl ether,
Examples include surfactants such as stearylamine hydrochloride, and water-soluble polymers such as polyethylene glycol, polyacrylamide, celluloses, and sodium polyacrylate. However, both have insufficient fluidity and lack practicality. The present inventors have continued intensive research to solve the above-mentioned problems in dispersants for coal-water slurries. As a result, a composition containing a certain polyether derivative, copolymer, and polyethylene glycol -We have completed the present invention by discovering that it has excellent effects as a dispersant for 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 [A] has the general formula H (OCH ₂ CH ₂ ) _n (R ₁ O) _l (CH ₂ CH ₂ O) _o H (wherein R ₁ is the number of carbon atoms 3 to 4 alkylene oxide residues, l is the average number of moles added, 10 to 4
200, m, n is the average number of added moles of ethylene oxide (50 to 1000), and the molecular weight is 5000 to 10.
10,000 water-soluble polyether derivatives () and [B] General formula (In the formula, R ₂ is hydrogen or a methyl group, R ₃ is an alkylene oxide residue having 2 to 4 carbon atoms, R ₄ is hydrogen or an alkyl group having 1 to 5 carbon atoms, and n is the average number of moles of alkylene oxide added. 1-100)
Polyalkylene glycol mono(meth)acrylic acid ester monomer [A] represented by
(Hereinafter referred to as monomer [a].) General formula (Meth)acrylic acid monomer [B] represented by (wherein, R ₅ is hydrogen or a methyl group, and X is hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group), (hereinafter, monomer [B]) and a monomer [C] copolymerizable with these monomers (hereinafter referred to as monomer [C]), monomer [B] 10 to 95% by weight %, monomer [B] 90 to 5% by weight and monomer [C] 0 to 50% by weight (however,
The total of [A], [B] and [C] is 100% by weight. ) derived copolymer (
A) and/or a copolymer (B) obtained by further neutralizing the copolymer (A) with an alkaline substance, and [C] polyethylene glycol with a molecular weight of 200 to 30,000. The present invention relates to a dispersant for coal-water slurry. 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 crushed 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 polyether derivative, copolymer and polyethylene glycol constituting the dispersant for coal-water slurry of the present invention can be produced by the following method. The water-soluble polyether derivative of the present invention with a molecular weight of 5,000 to 100,000 is represented by the general formula H(OCH ₂ CH ₂ ) _n (R ₁ O) _l (CH ₂ CH ₂ O) _o H, and R It is _an alkylene oxide residue having 3 to 4 carbon atoms. l is 10 to 200 and represents the average number of added moles of alkylene oxide, and m and n are 50 to 1000 and are the average number of added moles of ethylene oxide. This polyether derivative []
can be produced by a conventional method. Generally, water, propylene glycols, butylene glycols have various carbon atoms of 3 to 3.
After the alkylene oxide of No. 4, such as propylene oxide or butylene oxide, is subjected to an addition reaction under pressure using a catalyst such as an alkali or an acid in a conventional manner, ethylene oxide is added in the same manner. 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 content of ethylene oxide in the polyether derivative is usually 70% by weight or more, preferably 90 to 99.8% by weight. If the content of ethylene oxide is less than 70% by weight, the dispersibility of the coal will deteriorate and the viscosity will not decrease, which is not preferable. In the copolymerization of the present invention, monomer [a], monomer [b]
and a copolymer derived from monomer [c] (
A) and/or copolymers (B) can be used, preferably of the general formula (In the formula, R ₂ is hydrogen or a methyl group, R ₃ is an alkylene oxide residue having 2 to 4 carbon atoms, R ₄ is hydrogen or an alkyl group having 1 to 5 carbon atoms, and n is the average number of moles of alkylene oxide added. Monomer [A] represented by 1 to 100), general formula (In the formula, R ₅ is hydrogen or a methyl group, X is hydrogen,
Monomer [B] and monomer [C] represented by monovalent metal, divalent metal, ammonium group or organic amine group), monomer [B] 10 to 95% by weight, [B]
90-5% by weight and monomer [c] 0-50% by weight
(However, the total of [A], [B] and [C] is 100% by weight). This is a copolymer (B) obtained by neutralizing with an alkaline substance. Monomer [A] is represented by the above general formula and can be obtained by a known method. Examples of monomer [a] include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polybutylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, and methoxypolypropylene glycol mono(meth)acrylate. Examples include meth)acrylate, methoxypolybutylene glycol mono(meth)acrylate, ethoxypolyethylene glycol mono(meth)acrylate, ethoxypolypropylene glycol mono(meth)acrylate, ethoxypolybutylene glycol mono(meth)acrylate, etc.
One or more of these can be used. The monomer [b] is represented by the above general formula. Examples of monomers (b) include acrylic acid,
Examples include methacrylic acid and their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts, and one or more of these can be used. Monomer [c] is a monomer that can be copolymerized with monomer [a] and monomer [b]. Monomer [c]
Examples include esters of aliphatic alcohols having 1 to 20 carbon atoms and (meth)acrylic acid; (meth)
Acrylamide: Maleic acid, fumaric acid, or a monomer of these acids with an aliphatic alcohol having 1 to 20 carbon atoms, a glycol having 2 to 4 carbon atoms, or a polyalkylene glycol having an addition mole of 2 to 100 of these glycols. Esters or diesters; acetic acid alkenyl esters such as vinyl acetate and propenyl acetate; aromatic vinyls such as styrene, p-methylstyrene and styrene sulfonic acid; vinyl chloride; Can be used. Monomer [C] is in an amount within a range that makes the obtained copolymer (A) or copolymer (B) water-soluble, and monomer [A], monomer [B], and monomer It is used in an amount of 50% by weight or less based on the total amount of [c]. The copolymer (A) is produced by using monomers [a], monomers [b] and, if necessary, monomers [c] in the above-mentioned specific ratios. If the ratio is outside this range, a dispersant for coal-water slurry with excellent performance cannot be obtained. In order to produce the copolymer (A), 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 monomers and the obtained copolymer (A) and the convenience of using the copolymer (A), the monomers were selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms. It is preferable to use at least one kind. 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. In addition, for polymerization using lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, ethyl acetate, or ketone compounds as solvents,
Peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; and aliphatic azo compounds such as azobisisobutyronitrile 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 (A) thus obtained is
It can be used as is as a component of a dispersant, but
If necessary, a copolymer (B) obtained by further neutralizing with an alkaline substance may be used as a component of the dispersant. Preferred examples of such alkaline substances include hydroxides, chlorides, and carbonates of monovalent metals and divalent metals, ammonia, organic amines, and the like. Further, the molecular weight of the copolymer (A) can be in a wide range, but it is preferably in the range of 500 to 50,000. Copolymer (A) and/or copolymer (
B) can be used alone or in combination as a component of a dispersant. As the polyethylene glycol of the present invention, those produced by conventional methods can be used. Generally, it is obtained by adding ethylene oxide to water or ethylene glycols under pressure using an alkali catalyst in a conventional manner. Also, the molecular weight of polyethylene glycol is 200
Preferably, it is within the range of ~30,000. If it is outside this range, the performance as a dispersant will be insufficient, which is undesirable. The dispersant for coal-water slurry of the present invention contains a polyether derivative [], a copolymer (A) and/or (B), and a polyethylene glycol [], and the ratio of these two is that of polyether Derivative [] 98-30 parts by weight, copolymer ((A) and/or (B))
2-50 parts by weight polyethylene glycol []10-
A ratio of 50 parts by weight gives particularly good 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. To use the dispersant for coal-water slurry of the present invention, polyether derivatives [], copolymers (
A) and/or (B) and polyethylene glycol [] may be mixed in advance and then added at the time of slurry preparation, or polyether derivative [], copolymer ((A) and/or
Alternatively, (B)) and polyethylene glycol [] 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. Further, a rust preventive agent, a corrosion preventive agent, an antioxidant, an antifoaming agent, an antistatic agent, etc. can be added to the dispersant for coal-water slurry of the present invention as required. Particularly when preparing a coal-water slurry, when it is undesirable to generate air bubbles in the slurry, an antifoaming agent is usually added to the slurry. Examples of antifoaming agents include silicone-based, mineral oil-based, alcohol-based and fatty acid ester-based antifoaming agents. 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 the present invention is of course not limited thereto. In addition, unless otherwise specified in the examples, % is by weight.
, and parts represent parts by weight. Reference Example 1 390 parts of isopropyl alcohol (hereinafter abbreviated as IPA) was charged into a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, gas introduction tube, and reflux condenser, and the inside of the reaction vessel was replaced with nitrogen while stirring. and heated to boiling point in a nitrogen atmosphere. Next, 133 parts of methoxypolyethylene glycol monomethacrylate (“HK-ester M-9G” manufactured by Shin-Nakamura Chemical Co., Ltd., average number of added moles of ethylene oxide: 9),
27 parts methacrylic acid, benzoyl peroxide
120 parts of a mixture consisting of 2.44 parts and 240 parts of IPA
It was added in 120 minutes, and after the addition was complete, 0.49 parts of benzoyl peroxide was further dispersed in 10 parts of IPA.
It was added in two portions every 30 minutes. After the monomer addition was completed, the temperature was maintained at the boiling point for 120 minutes to complete the polymerization reaction. Thereafter, complete neutralization was performed with an aqueous solution of caustic soda, and IPA was distilled off to obtain an aqueous solution of copolymer [1]. 40 of this copolymer [1]
The pH and viscosity of the % aqueous solution were as shown in Table 1. Reference Example 2 390 parts of methanol was charged into the same reaction vessel as in Reference Example 1, the inside of the reaction vessel was replaced with nitrogen while stirring, and the mixture was heated to the boiling point in a nitrogen atmosphere. Next, 96 parts of polyethylene glycol monomethacrylate (“Premar PE350” manufactured by Nippon Oil & Fats Co., Ltd., average number of added moles of ethylene oxide 7 to 9), 64 parts of acrylic acid
a mixture of 6.67 parts of azobisisobutyronitrile and 240 parts of methanol was added over 120 minutes;
After the addition was completed, 1.33 parts of azobisisobutyronitrile dissolved in 10 parts of methanol was added in two portions every 30 minutes. After completing the monomer addition,
The temperature was maintained at boiling point for 120 minutes to complete the polymerization reaction. After that, complete neutralization was carried out with aqueous caustic soda solution, methanol was distilled off, and the copolymer [2]
An aqueous solution of was obtained. The pH and viscosity of a 40% aqueous solution of this copolymer [2] were as shown in Table 1. Reference example 3 560.7 parts of water was charged in the same reaction vessel as in reference example 1,
The inside of the reaction vessel was purged with nitrogen while stirring, and heated to 95°C in a nitrogen atmosphere. Next, 75 parts of methoxypolyethylene glycol monomethacrylate (“NK-Ester M-23G” manufactured by Shin-Nakamura Chemical Co., Ltd., average number of added moles of ethylene oxide 23), 25 parts of acrylic acid
5 parts and 300 parts of water.
% ammonium persulfate aqueous solution were added over 120 minutes, and after the addition was completed, 6.8 parts of a 5% ammonium persulfate aqueous solution was added over 20 minutes. After completing the addition of the above monomer mixed solution, 95℃ for 120 minutes.
The temperature was maintained to complete the polymerization reaction. After that, complete neutralization with caustic soda aqueous solution,
An aqueous solution of copolymer [3] was obtained. The pH and viscosity of a 40% aqueous solution of this copolymer [3] were as shown in Table 1. Reference example 4 390 parts of IPA was charged in the same reaction vessel as in reference example 1,
The inside of the reaction vessel was purged with nitrogen while stirring, and heated to the boiling point in a nitrogen atmosphere. Next, polypropylene glycol monomethacrylate (“Premer-PP-
A mixture consisting of 91 parts of propylene oxide, 69 parts of acrylic acid, 4.80 parts of benzoyl peroxide, and 240 parts of IPA was added over 120 minutes, and after the addition was completed,
0.96 parts of benzoyl peroxide dispersed in 10 parts of IPA was added in two portions every 30 minutes.
After the monomer addition was completed, the temperature was maintained at the boiling point for 120 minutes to complete the polymerization reaction. Thereafter, complete neutralization was performed with an aqueous solution of caustic soda, and IPA was distilled off to obtain an aqueous solution of copolymer [4]. The pH and viscosity of a 40% aqueous solution of this copolymer [4] were as shown in Table 1. Reference Example 5 In the same reaction vessel as Reference Example 1, add 141.2 parts of water and
170 parts of IPA was charged, and the inside of the reaction vessel was replaced with nitrogen while stirring, and heated to the boiling point in a nitrogen atmosphere. Next, methoxypolyethylene glycol monomethacrylate (“HK Ester M-23G” Shin-Nakamura Chemical Co., Ltd.)
(average number of added moles of ethylene oxide 23) 72
A mixture of 48 parts of acrylic acid, 90 parts of IPA and 90 parts of water, a mixture of 40 parts of acrylamide, 60 parts of IPA and 60 parts of water, and 48 parts of 10% ammonium persulfate were added over 120 minutes, and after the addition was complete. Add 4.8 parts of 10% ammonium persulfate to 30
Addition was made in two portions, each minute apart. After the monomer addition was completed, the temperature was maintained at the boiling point for 120 minutes to complete the polymerization reaction. Thereafter, complete neutralization was performed with an aqueous solution of caustic soda, and IPA was distilled off to obtain an aqueous solution of copolymer [5]. The pH and viscosity of a 40% aqueous solution of this copolymer [5] were as shown in Table 1. Reference example 6 390 parts of IPA was charged in the same reaction vessel as in reference example 1,
The inside of the reaction vessel was purged with nitrogen while stirring, and heated to the boiling point in a nitrogen atmosphere. Next, 88 parts of methoxypolyethylene glycol monomethacrylate (“NK Ester M-23G” manufactured by Shin Nakamura Chemical Co., Ltd., average number of added moles of ethylene oxide 23), 64 parts of acrylic acid
parts, 8 parts of styrene, 2.4 parts of benzoyl peroxide
and 240 parts of IPA were added over 120 minutes, and after the addition was complete, 0.48 parts of benzoyl peroxide dispersed in 10 parts of IPA was added every 30 minutes.
It was added in batches. After completing the monomer addition,
The polymerization reaction was completed by holding at boiling point for 120 minutes.
Thereafter, complete neutralization was performed with an aqueous solution of caustic soda, and IPA was distilled off to obtain an aqueous solution of copolymer [6]. The pH and viscosity of a 40% aqueous solution of this copolymer [6] were as shown in Table 1.

[Table] Reference example 7 Polyethylene glycol (hereinafter referred to as PEG)
A commercially available product manufactured by Sanyo Chemical Industries, Ltd. was used. The product name and average molecular weight are shown in Table 2.

[Table] Examples (1 to 17) and Comparative Examples (1 to 10) Aqueous solutions containing predetermined amounts of various dispersants shown in Table 3
69.7g of pulverized coal (moisture content 6.8%), which has been crushed to pass 73% through a 200 mesh sieve, is added little by little at room temperature to 30.3g of pulverized coal. manufactured by)
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-3. Low viscosity indicates good fluidity.

【table】

[Table] Example 18 A coal-water slurry was prepared by adding 100 ppm (based on slurry) of a silicone antifoaming agent to the composition of Example 2 in the same manner as in Examples 1 to 17. The measurement results of viscosity and bubble content are shown in Table 4.

【table】

Claims (1)

[Claims] 1 [A] General formula H (OCH ₂ CH ₂ ) _n (R ₁ O) _l (CH ₂ CH ₂ O) _o H (wherein R ₁ is an alkylene oxide having 3 to 4 carbon atoms Residue, l is the average number of moles added, 10 ~
200, m and n are the average number of moles of ethylene oxide added (50 to 1000) A water-soluble polyether derivative () with a molecular weight of 5000 to 100,000, [B] General formula (In the formula, R ₂ is hydrogen or a methyl group, R ₃ is an alkylene oxide residue having 2 to 4 carbon atoms, R ₄ is hydrogen or an alkyl group having 1 to 5 carbon atoms, and n is the average number of moles of alkylene oxide added. 1~100
Polyalkylene glycol mono(meth)acrylic acid ester monomer [A] represented by the general formula (In the formula, R ₅ is hydrogen or a methyl group, and X is hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group.) a monomer copolymerizable with the polymer [C], a polyalkylene glycol mono(meth)acrylic acid ester monomer [B] 10 to 95% by weight,
(meth)acrylic acid monomer [B] 90 to 5% by weight and monomer [C] 0 to 50% by weight (however,
The total of [A], [B] and [C] is 100% by weight. ) derived copolymer (
A) and/or a copolymer (B) obtained by further neutralizing the copolymer (A) with an alkaline substance, and [C] polyethylene glycol () having a molecular weight of 200 to 30,000. Coal
Dispersant for water slurry. 2. The dispersant according to claim 1, which contains at least 70% by weight of ethylene oxide in the polyether derivative (). 3 The copolymer (A) is a polyalkylene glycol mono(meth)acrylic acid ester monomer [a] and a (meth)acrylic acid monomer [b]
, the former 50-80% by weight and the latter 20-50% by weight
(However, the total of both is 100% by weight.) Claim 1
Dispersant as described in section. 4. The dispersant according to claim 1, which contains an antifoaming agent.