Sulfur-free coal water slurry dispersing agent and preparation method thereof

Abstract

The sulfur-free coal water slurry dispersing agent is prepared from the following raw materials in parts by mass: 273.7 to 505.3 parts of carboxylic acid monomer, 10 to 63.2 parts of amide monomer or 10 to 52.6 parts of polyether monomer, 4.2 to 25.2 parts of initiator, 10.0 to 108.0 parts of chain transfer agent, 2.1 to 4.2 parts of stabilizer, 18.9 to 157.8 parts of neutralizer and 400.0 to 900.0 parts of deionized water. The preparation method comprises the following steps: synthesizing a novel sulfur-free macromonomer from organic acid and an amide monomer / polyether monomer under the action of an initiator and a chain transfer agent, adjusting the pH value of the newly synthesized macromonomer by using an alkaline substance, and adding a polymerization inhibitor to prevent continuous polymerization of a macromolecular substance, thereby obtaining the sulfur-free coal water slurry dispersing agent. The coal water slurry dispersing agent prepared by the invention does not contain sulfur, so that the corrosion of the dispersing agent to the bottom of a tank during storage is reduced, and the desulfurization cost of a subsequent coal chemical process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of dispersants, and in particular to a sulfur-free coal water slurry dispersant and a preparation method thereof. Background Art

[0002] As an important alternative fuel and new clean energy source, coal-water slurry (CWS) boasts a high burnout rate, a calorific value more than half that of petroleum, and higher energy efficiency than other fossil fuels. Dispersants are essential additives in the CWS preparation process, increasing its concentration and stability.

[0003] There are many types of dispersants for coal water slurry, which are mainly divided into four categories according to their structure: sulfonate type, lignin type, polycarboxylic acid type and naphthalene type. For example, the patent application with publication number CN111808641A discloses a novel coal water slurry dispersant and its preparation method. By modifying the residue of 2-naphthol distillation-rectification, a dispersant with environmental protection, low cost and excellent performance was successfully developed. This dispersant replaces part of the phenol with components such as 2-naphthol and 1-naphthol in the residue, and introduces active groups such as sodium naphthalenesulfonate formaldehyde polymer, which significantly improves the dispersion effect and stability of coal water slurry. However, due to the presence of naphthalenesulfonate in its ingredients, the problem of sulfur content is still inevitable. Panitha Phulkerd abroad successfully synthesized cardanol-formaldehyde sulfonate (CFS) by sulfonating and methylating cardanol. This new dispersant uses natural and renewable cardanol as raw material and has good surface activity and dispersibility. However, due to the sulfonation reaction involved in its synthesis process, it still inevitably contains a certain amount of sulfur. These products may impose certain limitations on certain applications that are sensitive to sulfur content.

[0004] Current CWS dispersants contain high levels of sulfur, necessitating subsequent desulfurization of tail gas. This can add tens to hundreds of yuan to the desulfurization cost per ton of CWS. Consequently, some companies are using low-sulfur coal to prepare CWS to reduce desulfurization costs. In these cases, the sulfur in the CWS dispersant can impose a significant burden on subsequent desulfurization. Therefore, in-depth research into the preparation process, mechanism of action, and application performance of sulfur-free, environmentally friendly CWS dispersants is of great theoretical and practical significance. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to propose a sulfur-free water-coal slurry dispersant and a preparation method thereof, wherein an organic acid and an amide monomer / polyether monomer are synthesized into a new type of sulfur-free macromonomer under the action of an initiator and a chain transfer agent, the pH of the newly synthesized macromonomer is adjusted with an alkaline substance, and an inhibitor is added to prevent the high molecular weight substance from continuing to polymerize, thereby obtaining a new type of sulfur-free water-coal slurry dispersant; the water-coal slurry dispersant prepared by the present invention does not contain sulfur element, reduces the corrosion of the dispersant on the tank bottom during storage, and reduces the desulfurization cost of subsequent coal chemical processes.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A sulfur-free coal water slurry dispersant comprises raw materials, calculated by weight, comprising 273.7-505.3 parts of carboxylic acid monomers, 10-63.2 parts of amide monomers or 10-52.6 parts of polyether monomers, 4.2-25.2 parts of initiators, 10.0-108.0 parts of chain transfer agents, 2.1-4.2 parts of stabilizers, 18.9-157.8 parts of neutralizers, and 400.0-900.0 parts of deionized water.

[0008] The carboxylic acid monomer is one or more of acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, ethyl methacrylate, itaconic acid or maleic anhydride.

[0009] The amide monomer is one of acrylamide, diacetone acrylamide or acrylamidoethanol (AGE).

[0010] The polyether monomer is one of polyglycerol polyoxyethylene ether, isopentanol polyoxyethylene ether (TPEG) or methoxy polyethylene glycol (MPEG).

[0011] The initiator is one of benzoyl peroxide, di-tert-butyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile or dimethyl azobisisobutyrate.

[0012] The chain transfer agent is one of isopropyl alcohol, n-propyl alcohol, n-butanol or polypropylene glycol.

[0013] The stabilizer is one of hydroquinone, resorcinol, p-phenylenediamine or p-toluidine.

[0014] The neutralizing agent is one of saturated sodium hydroxide solution, saturated potassium hydroxide solution, saturated sodium bicarbonate solution, 20% ammonia water (the rest of the raw materials are analytically pure), triethanolamine or dimethylethanolamine.

[0015] In the sulfur-free coal water slurry dispersant, the amount of other raw materials except water accounts for 10%-60% of the total raw material amount.

[0016] The preparation method of the above-mentioned sulfur-free coal water slurry dispersant comprises:

[0017] Step 1: Add 68.4-126.3 parts of carboxylic acid monomer, 10-31.6 parts of amide monomer or 10-26.3 parts of polyether monomer, 1.4-8.4 parts of initiator, 10.0-108.0 parts of chain transfer agent, 2.1-4.2 parts of stabilizer and 133.3-300.0 parts of water into a reaction vessel, and reflux at 60-80° C. for 10-30 minutes;

[0018] Step 2: Liquid A and Liquid B are added dropwise to the solution obtained in Step 1 simultaneously over 45-60 minutes, and the reaction is continued by heat preservation for 60-120 minutes; the Liquid A is a mixture of 205.3-379.0 parts of carboxylic acid monomer, 10-31.6 parts of amide monomer or 10-26.3 parts of polyether monomer and 133.3-300.0 parts of water; the Liquid B is a mixture of 2.8-16.8 parts of initiator and 133.4-300.0 parts of water;

[0019] Step 3: After the reaction is completed, the solution is taken out and cooled to room temperature, and 18.9-157.8 parts of a neutralizer are added to adjust the pH of the solution to 7-8.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The amide monomer / polyether monomer and the carboxylic acid monomer of the present invention first undergo self-polymerization under the action of an initiator and a chain transfer agent to form an intrapolymer. Then, under the action of the added initiator, part of the intrapolymer undergoes a graft reaction with the newly added carboxylic acid monomer to form a graft copolymer. A polymerization inhibitor is added to prevent the high molecular weight substance from continuing to polymerize. Finally, a neutralizing agent is added for alkalization. The prepared water-coal slurry dispersant does not contain sulfur element, reduces corrosion of the dispersant on the tank bottom during storage, and reduces the desulfurization cost of the subsequent coal chemical process.

[0022] 2. When the dispersant prepared by the present invention is added to the coal water slurry, the concentration of the coal water slurry reaches 50%-60%, and it still does not aggregate and precipitate, and remains stably dispersed in the solution. Therefore, the concentration of the coal water slurry can be increased, the transportation cost of the coal water slurry can be reduced, and the calorific value of the coal water slurry can be increased.

[0023] In summary, the present invention completes the preparation process of the sulfur-free dispersant in three steps, simplifies the process, reduces the difficulty of synthesizing the water-coal slurry dispersant, facilitates subsequent industrial production, provides theoretical and technical support for the development of efficient and environmentally friendly dispersants, and contributes to the clean and efficient utilization of coal resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a reaction process diagram of Example 1. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] A sulfur-free coal water slurry dispersant, comprising, based on 1000 parts by weight of the total raw materials, 380.0 parts of acrylic acid (carboxylic acid monomer), 20.0 parts of isopentanol polyoxyethylene ether (polyether monomer), 4.5 parts of azobisisoheptonitrile (initiator), 40.0 parts of isopropyl alcohol (chain transfer agent), 3.0 parts of hydroquinone (stabilizer), 52.5 parts of 20% ammonia water (neutralizer), and 500 parts of water; and a preparation method thereof is as follows:

[0028] Step 1: Add 95 parts of acrylic acid, 20 parts of isopentanol polyoxyethylene ether, 1.5 parts of azobisisoheptanenitrile, 40.0 parts of isopropyl alcohol, 3.0 parts of hydroquinone and 166.6 parts of water to a four-necked flask equipped with a stirrer and a thermometer, and reflux under condensation at 70°C for 15 minutes;

[0029] Step 2: Add 3.0 parts of azobisisoheptanenitrile and 285 parts of acrylic acid to 166.7 parts of water respectively, dissolve them and add them dropwise to the solution obtained in step 1 at the same time. Control the flow rate so that the solution is added within 50 minutes. Seal and keep warm for 2 hours.

[0030] Step 3: After the reaction is completed, take out the sample and cool it to room temperature, then add 52.5 parts of 20% ammonia water dropwise to adjust the pH to 7-8 to obtain a sulfur-free coal water slurry dispersant.

[0031] Performance Testing

[0032] The dispersant prepared by the present invention is added to the water-coal slurry obtained by adding coal powder and water in a ball mill at a ratio of 60:40 and stirring. The viscosity of the slurry at 60 r / s using a DV-C digital viscometer is as follows:

[0033] Table 1

[0034]

[0035] As can be seen from Table 1, the water-coal slurry of the dispersant prepared by the present invention has the lowest viscosity and the best dispersibility when the addition amount is 1.4g, and when the addition amount is small, the lowest viscosity is much lower than the water-coal slurry viscosity of the commercially available dispersant.

[0036] The reaction mechanism of this embodiment is as follows Figure 1As shown, the polyether monomer and the carboxylic acid monomer first undergo internal polymerization under the action of an initiator and a chain transfer agent to form internal polymers a and b. Then, under the action of the added initiator, part of the internal polymers a and b undergo a graft reaction with the newly added carboxylic acid monomer to form a graft copolymer c. An inhibitor is added to prevent the polymer from continuing to polymerize. Finally, a neutralizer is added for alkalization to obtain a new sulfur-free coal water slurry dispersant.

[0037] Example 2

[0038] A sulfur-free coal water slurry dispersant, comprising, based on 1000 parts by weight of the total raw materials, 505.3 parts of methacrylic acid (carboxylic acid monomer), 30.0 parts of polyglycerol polyoxyethylene ether (polyether monomer), 20.0 parts of benzoyl peroxide (initiator), 80.0 parts of n-butanol (chain transfer agent), 4.2 parts of p-phenylenediamine (stabilizer), 20.0 parts of saturated sodium hydroxide solution (neutralizer), and 340.5 parts of water; and a preparation method thereof is as follows:

[0039] Step 1: In a four-necked flask equipped with a stirrer and a thermometer, 126.3 parts of methacrylic acid, 30.0 parts of polyglycerol polyoxyethylene ether, 6.6 parts of benzoyl peroxide, 113.5 parts of n-butanol, 4.2 parts of p-phenylenediamine and 113.5 parts of water were added, and the mixture was refluxed at 70° C. for 15 minutes;

[0040] Step 2: Add 13.4 parts of benzoyl peroxide and 379 parts of methacrylic acid to 113.5 parts of water respectively, dissolve them and add them dropwise to the solution obtained in step 1 at the same time, control the flow rate so that the solution is added within 50 minutes, and seal and keep warm for 2 hours;

[0041] Step 3: After the reaction is completed, take out the sample and cool it to room temperature, then add 20.0 parts of saturated sodium hydroxide solution dropwise to adjust the pH to 7-8 to obtain a sulfur-free coal water slurry dispersant.

[0042] Performance Testing

[0043] The dispersant prepared by the present invention is added to the water-coal slurry obtained by adding coal powder and water in a ball mill at a ratio of 60:40 and stirring. The viscosity of the slurry at 60 r / s using a DV-C digital viscometer is as follows:

[0044] Table 2

[0045] Addition amount / g 1.2 1.4 1.6 1.8 2.0 Viscosity / mPa*s 359 271 226 182 204

[0046] As can be seen from Table 2, the coal-water slurry prepared using the homemade dispersant of Example 2 has the lowest viscosity and the best dispersibility when 1.8 g is added.

[0047] Example 3

[0048] A sulfur-free coal water slurry dispersant, comprising, based on 1000 parts by weight of the total raw materials, 273.7 parts of itaconic acid (carboxylic acid monomer), 20.0 parts of methoxypolyethylene glycol (polyether monomer), 10.0 parts of azobisisobutyronitrile (initiator), 60.0 parts of isopropyl alcohol (chain transfer agent), 2.1 parts of p-toluidine (stabilizer), 80 parts of 20% ammonia water (neutralizer), and 554.2 parts of water; and a preparation method thereof is as follows:

[0049] Step 1: In a four-necked flask equipped with a stirrer and a thermometer, 68.4 parts of acrylic acid, 20 parts of methoxypolyethylene glycol, 3.4 parts of azobisisobutyronitrile, 60.0 parts of isopropyl alcohol, 2.1 parts of p-toluidine and 184.8 parts of water were added, and the mixture was refluxed at 70° C. for 15 minutes;

[0050] Step 2: Add 6.6 parts of azobisisobutyronitrile and 205.3 parts of itaconic acid to 184.7 parts of water respectively, dissolve them and add them dropwise to the solution obtained in step 1 at the same time. Control the flow rate so that the solution is added after 50 minutes. Seal and keep warm for 2 hours.

[0051] Step 3: After the reaction is completed, take out the sample and cool it to room temperature, then add 80.0 parts of 20% ammonia water dropwise to adjust the pH to 7-8 to obtain a sulfur-free coal water slurry dispersant.

[0052] Performance Testing

[0053] The dispersant prepared by the present invention is added to the water-coal slurry obtained by adding coal powder and water in a ball mill at a ratio of 60:40 and stirring. The viscosity of the slurry at 60 r / s using a DV-C digital viscometer is as follows:

[0054] Table 3

[0055] Addition amount / g 1.2 1.4 1.6 1.8 2.0 Viscosity / mPa*s 309 284 255 271 277

[0056] As can be seen from Table 3, the coal-water slurry prepared using the self-made dispersant of Example 3 has the lowest viscosity and the best dispersion effect when the addition amount is 1.6 g.

[0057] Example 4

[0058] A sulfur-free coal water slurry dispersant, comprising, based on 1000 parts by weight of the total raw materials, 240.0 parts of acrylic acid (carboxylic acid monomer), 60.0 parts of methacrylic acid (carboxylic acid monomer), 24.0 parts of acrylamide (amide monomer, 6.0 parts of benzoyl peroxide (initiator), 90.0 parts of isopropyl alcohol (chain transfer agent), 3.0 parts of hydroquinone (stabilizer), 50 parts of 20% ammonia water (neutralizer), and 527.0 parts of water; the preparation method thereof is specifically as follows:

[0059] Step 1: In a four-necked flask equipped with a stirrer and a thermometer, 160.0 parts of acrylic acid, 60.0 parts of methacrylic acid, 12 parts of acrylamide, 2.0 parts of benzoyl peroxide, 90.0 parts of isopropyl alcohol, 3.0 parts of hydroquinone and 263.5 parts of water were added, and the mixture was refluxed at 70° C. for 20 minutes;

[0060] Step 2: Add 4.0 parts of benzoyl peroxide to 87.8 parts of water, and add 80.0 parts of acrylic acid and 12.0 parts of acrylamide to 175.7 parts of water respectively. After dissolving, add them dropwise to the solution obtained in step 1 at the same time. Control the flow rate so that the solution is added within 50 minutes. Seal and keep warm for 2 hours.

[0061] Step 3: After the reaction is completed, take out the sample and cool it to room temperature, then add 50.0 parts of 20% ammonia water to adjust the pH to 7-8 to obtain a sulfur-free coal water slurry dispersant.

[0062] Performance Testing

[0063] The dispersant prepared by the present invention is added to the water-coal slurry obtained by adding coal powder and water in a ball mill at a ratio of 60:40 and stirring. The viscosity of the slurry at 60 r / s using a DV-C digital viscometer is as follows:

[0064] Table 4

[0065] Addition amount / g 1.2 1.4 1.6 1.8 2.0 Viscosity / mPa*s 462 306 285 298 313

[0066] As can be seen from Table 4, the coal-water slurry prepared using the homemade dispersant of Example 4 has the lowest viscosity and the best dispersibility when 1.6 g is added.

[0067] Example 5

[0068] A sulfur-free coal water slurry dispersant, wherein the total raw materials, calculated on a mass basis as 1000 parts, include: 300.0 parts of ethyl acrylate (carboxylic acid monomer), 89.5 parts of methacrylic acid (carboxylic acid monomer), 31.6 parts of acrylamidoethanol (amide monomer), 6.2 parts of benzoyl peroxide (initiator), 45.0 parts of isopropyl alcohol (chain transfer agent), 4.0 parts of hydroquinone (stabilizer), 111.0 parts of 20% ammonia water (neutralizer), and 412.7 parts of water; and the preparation method thereof is as follows:

[0069] Step 1: In a four-necked flask equipped with a stirrer and a thermometer, 200.0 parts of ethyl acrylate, 89.5 parts of methacrylic acid, 15.8 parts of acrylamidoethanol, 2.1 parts of benzoyl peroxide, 45.0 parts of isopropyl alcohol, 4.0 parts of p-phenylenediamine and 206.3 parts of water were added, and the mixture was refluxed at 70° C. for 20 minutes;

[0070] Step 2: Add 4.1 parts of benzoyl peroxide to 68.8 parts of water, and add 100.0 parts of ethyl acrylate and 15.8 parts of acrylamidoethanol to 137.6 parts of water respectively. After dissolving, add them dropwise to the solution obtained in step 1 at the same time. Control the flow rate so that the solution is added within 50 minutes. Seal and keep warm for 2 hours.

[0071] Step 3: After the reaction is completed, the sample is taken out and cooled to room temperature, and 111.0 parts of 20% ammonia water are added dropwise to adjust the pH to 7-8 to obtain a sulfur-free coal water slurry dispersant.

[0072] Performance Testing

[0073] The dispersant prepared by the present invention is added to the water-coal slurry obtained by adding coal powder and water in a ball mill at a ratio of 60:40 and stirring. The viscosity of the slurry at 60 r / s using a DV-C digital viscometer is as follows:

[0074] Table 5

[0075] Addition amount / g 1.2 1.4 1.6 1.8 2.0 Viscosity / mPa*s 483 392 365 327 391

[0076] As can be seen from Table 5, the coal-water slurry prepared using the homemade dispersant of Example 5 has the lowest viscosity and the best dispersibility when 1.8 g is added.

[0077] In summary, the sulfur-free CWS dispersant prepared by the present invention can reduce the apparent viscosity of a 60% CWS to 100 mPa·s, achieve a maximum CWS concentration of 66%, and show no noticeable stratification after seven days of standing. These three performances are superior to those of the CWS dispersants currently used by manufacturers. Elemental analysis of the sulfur-free CWS dispersant confirmed that it contains no sulfur.

Claims

1. A sulfur-free coal water slurry dispersant, characterized in that: The raw materials, calculated by weight, include 273.7-505.3 parts of carboxylic acid monomer, 10-63.2 parts of amide monomer or 10-52.6 parts of polyether monomer, 4.2-25.2 parts of initiator, 10.0-108.0 parts of chain transfer agent, 2.1-4.2 parts of stabilizer, 18.9-157.8 parts of neutralizer, and 400.0-900.0 parts of deionized water.

2. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that, The carboxylic acid monomer is one or more of acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, ethyl methacrylate, itaconic acid or maleic anhydride.

3. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that: The amide monomer is one of acrylamide, diacetone acrylamide or acrylamidoethanol (AGE).

4. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that: The polyether monomer is one of polyglycerol polyoxyethylene ether, isopentanol polyoxyethylene ether (TPEG) or methoxy polyethylene glycol (MPEG).

5. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that: The initiator is one of benzoyl peroxide, di-tert-butyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile or dimethyl azobisisobutyrate.

6. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that: The chain transfer agent is one of isopropyl alcohol, n-propyl alcohol, n-butanol or polypropylene glycol.

7. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that: The stabilizer is one of hydroquinone, resorcinol, p-phenylenediamine or p-toluidine.

8. The sulfur-free coal water slurry dispersant according to claim 1, characterized in that: The neutralizing agent is one of saturated sodium hydroxide solution, saturated potassium hydroxide solution, saturated sodium bicarbonate solution, 20% ammonia water (the rest of the raw materials are analytically pure), triethanolamine or dimethylethanolamine.

9. A sulfur-free coal water slurry dispersant according to claim 1, characterized in that: In the sulfur-free coal water slurry dispersant, the amount of other raw materials except water accounts for 10%-60% of the total raw material amount.

10. The method for preparing a sulfur-free coal water slurry dispersant according to any one of claims 1 to 9, characterized in that: include: Step 1: Add 68.4-126.3 parts of carboxylic acid monomer, 10-31.6 parts of amide monomer or 10-26.3 parts of polyether monomer, 1.4-8.4 parts of initiator, 10.0-108.0 parts of chain transfer agent, 2.1-4.2 parts of stabilizer and 133.3-300.0 parts of water into a reaction vessel, and reflux at 60-80° C. for 10-30 minutes; Step 2: Liquid A and Liquid B are added dropwise to the solution obtained in Step 1 simultaneously over 45-60 minutes, and the reaction is continued by heat preservation for 60-120 minutes; the Liquid A is a mixture of 205.3-379.0 parts of carboxylic acid monomer, 10-31.6 parts of amide monomer or 10-26.3 parts of polyether monomer and 133.3-300.0 parts of water; the Liquid B is a mixture of 2.8-16.8 parts of initiator and 133.4-300.0 parts of water; Step 3: After the reaction is completed, the solution is taken out and cooled to room temperature, and 18.9-157.8 parts of a neutralizer are added to adjust the pH of the solution to 7-8.

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