A naphthalene sulfonate modified coal water slurry dispersing stabilizer, a preparation method and application thereof

Abstract

This invention provides a naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, its preparation method, and its application. By weight, the raw materials include: 22-38 parts of rosin polyether-modified naphthalene sulfonate condensate, 1.5-3.5 parts of borate ester dynamically cross-linked cellulose microgel, 0.8-2.0 parts of auxiliary stabilizer, 5-10 parts of polycarboxylate-based water-reducing agent, 8-15 parts of sulfonated lignin, 0.8-2.5 parts of isomeric tridecyl alcohol polyoxyethylene ether, 5-10 parts of antifreeze and humectant, 2.5-5 parts of sodium gluconate, 0.4-1.0 parts of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, 0.15-0.6 parts of polyether-modified polysiloxane, and 30-50 parts of deionized water. The synergistic effect of the components in this invention allows the prepared coal-water slurry dispersion stabilizer to effectively regulate the rheological and stability properties of coal-water slurry, adapting to the performance requirements of coal-water slurry in biomass dense molding fuel processing.

Description

Technical Field

[0001] This invention relates to the field of coal chemical technology, specifically to a naphthalene sulfonate-modified coal-water slurry dispersant and stabilizer, its preparation method, and its application. Background Technology

[0002] Coal-water slurry, as a clean coal-based fluid fuel, combines the combustion characteristics of coal with the transportation advantages of liquid fuels. It is widely used in industrial combustion and gasification, and can also be used as a raw material additive in the processing of biomass densified fuels, becoming a key carrier for the comprehensive utilization of coal resources and biomass energy. The dispersion stability of coal-water slurry is a core indicator determining its storage, transportation, and usage performance. Naphthalene sulfonate compounds, due to their good surface activity and dispersibility, have become commonly used basic raw materials for preparing coal-water slurry dispersion stabilizers.

[0003] In existing technologies, some progress has been made in the modification of naphthalene sulfonate additives. Various modified naphthalene sulfonates, gel stabilizers, and auxiliary dispersants have been successively applied to coal-water slurry systems. Related technologies aim to improve the comprehensive performance of coal-water slurry through multi-component compounding. However, the coal-water slurry prepared by these technologies still cannot meet the performance requirements of coal-water slurry raw materials in the biomass compaction fuel processing process. On the one hand, existing modified naphthalene sulfonate coal-water slurry additives have insufficient synergistic effects on the dispersion, wetting, and penetration of coal particles, resulting in poor slurry formability and limited ability to control rheological properties, which cannot meet the process adaptability requirements of biomass compaction fuel processing. On the other hand, existing additive systems cannot simultaneously achieve long-term stable storage of coal-water slurry and performance maintenance under complex working conditions. The prepared coal-water slurry is prone to stratification and sedimentation. Moreover, this type of additive system is susceptible to interference from metal ions and pH fluctuations, significantly limiting the function of each component and thus failing to guarantee the performance stability and consistency of coal-water slurry throughout the entire biomass compaction fuel processing process. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a naphthalene sulfonate modified coal-water slurry dispersant stabilizer, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a naphthalene sulfonate modified coal-water slurry dispersion stabilizer, which, by weight, comprises the following raw materials: 22-38 parts of rosin polyether modified naphthalene sulfonate condensate, 1.5-3.5 parts of borate ester dynamically crosslinked cellulose microgel, 0.8-2.0 parts of auxiliary stabilizer, 5-10 parts of polycarboxylate water-reducing agent, 8-15 parts of sulfonated lignin, 0.8-2.5 parts of isotridecyl alcohol polyoxyethylene ether, 5-10 parts of antifreeze and humectant, 2.5-5 parts of sodium gluconate, 0.4-1.0 parts of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, 0.15-0.6 parts of polyether modified polysiloxane, and 30-50 parts of deionized water.

[0006] Using the above technical solutions, rosin polyether modified naphthalene sulfonate condensate can effectively disperse coal particles and improve the dispersion performance of coal-water slurry; borate ester dynamically crosslinked cellulose microgel can enhance the stability of coal-water slurry and improve its thixotropic properties; auxiliary stabilizers can further improve the system stability of coal-water slurry; polycarboxylate superplasticizers and sulfonated lignin synergistically play an auxiliary dispersion role, strengthening the dispersion effect of coal particles; isomeric tridecyl alcohol polyoxyethylene ether can improve the wetting and penetration effect of coal particles and optimize the slurry formability; antifreeze and humectant can lower the freezing point of the coal-water slurry system and maintain the rheological properties of the slurry at low temperatures; sodium gluconate can chelate the slurry... Metal ions inhibit the destructive effect of metal ions on the dispersion and stabilization system; the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair maintains the pH stability of the slurry system, ensuring the normal functioning of each component; polyether-modified polysiloxane can inhibit foam generation during the preparation and use of coal-water slurry, improving the homogeneity of the slurry; deionized water, as a solvent, provides a uniform reaction system for the dispersion and action of each component; the synergistic cooperation and complementary effects of each component result in a coal-water slurry dispersion stabilizer that can effectively regulate the rheological properties and stability of coal-water slurry, thereby meeting the various performance requirements of coal-water slurry raw materials in the process of biomass compacted fuel processing.

[0007] Preferably, the auxiliary stabilizer is one of xanthan gum or sorbitol, and the antifreeze and moisturizing agent is a compound of propylene glycol and sorbitol in a mass ratio of 4:1-6:1; the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer is added in an aqueous solution of 0.02-0.06 mol / L, and the pH of the naphthalenesulfonate modified coal-water slurry dispersion stabilizer system is 8.0-8.5.

[0008] Using the above technical solution, xanthan gum or sorbitol is used as an auxiliary stabilizer, which can enhance the system stability of this dispersion stabilizer by forming a hydrogen bond network, and reduce the separation and precipitation of water-coal slurry in combination with other components. The antifreeze and moisturizing agent formed by compounding propylene glycol and sorbitol in a mass ratio of 4:1-6:1 can play a synergistic antifreeze and moisturizing role, effectively reducing the freezing point of the system and inhibiting ice crystal growth, thereby maintaining the rheological properties and performance of water-coal slurry in low-temperature environments. The addition of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer in an aqueous solution of 0.02-0.06 mol / L can stabilize the pH value of the naphthalenesulfonate modified water-coal slurry dispersion stabilizer system at 8.0-8.5, ensuring that the functions of each component can be performed normally and effectively maintaining the structural integrity and performance of the dispersion stabilizer.

[0009] Preferably, the raw materials for preparing the rosin polyether modified naphthalene sulfonate condensate, by weight, include: 90-100 parts of disproportionated rosin, 0.4-0.8 parts of potassium hydroxide, 35-60 parts of ethylene oxide, 90-100 parts of industrial naphthalene, 130-150 parts of concentrated sulfuric acid, 70-100 parts of a formaldehyde aqueous solution with a mass fraction of 35%-37%, 20-30 parts of deionized water, and 1-2 parts of glacial acetic acid.

[0010] Using the above technical solution, disproportionated rosin can provide rosin groups, providing hydrophobic groups for the final rosin polyether-modified naphthalene sulfonate condensate; potassium hydroxide can act as a catalyst to promote the reaction between disproportionated rosin and ethylene oxide; ethylene oxide can undergo an addition reaction with disproportionated rosin to generate a rosin-based polyether intermediate, introducing polyether segments into the final product; industrial naphthalene can undergo a sulfonation reaction with concentrated sulfuric acid to generate a naphthalene sulfonic acid structure, which, after neutralization, forms a naphthalene sulfonate structure, providing hydrophilic groups for the final product; concentrated sulfuric acid acts as a sulfonating agent to realize the sulfonation reaction of industrial naphthalene; a 35%-37% formaldehyde aqueous solution can participate in the condensation reaction to achieve covalent bonding between the rosin-based polyether intermediate and the naphthalene sulfonate; deionized water can be used for the hydrolysis reaction after sulfonation to adjust the pH and viscosity of the reaction system; glacial acetic acid can neutralize the alkaline catalyst in the reaction system, terminate the catalytic reaction, and end-cap the rosin-based polyether intermediate. After the above series of reactions, the raw materials synergistically generate the rosin polyether-modified naphthalene sulfonate condensate.

[0011] Preferably, the preparation method of the rosin polyether modified naphthalene sulfonate condensate includes the following steps: 1) Add disproportionated rosin and potassium hydroxide to the high-pressure reactor, replace the air in the reactor with nitrogen until the oxygen content is ≤0.5%, start stirring at 200-300 r / min, raise the temperature to 145-165℃, maintain the vacuum at -0.085MPa~-0.095MPa, and keep it at the temperature for dehydration for 30-45 min; 2) Ethylene oxide is introduced into the system obtained in step 1), and the pressure is controlled at 0.45-0.55 MPa and the temperature at 155-175℃. The mixture is stirred at 200-300 r / min for 3.5-5 h until the pressure is constant. The temperature is then lowered to 75-85℃, and the pH is neutralized with glacial acetic acid to 6.5-7.5. The mixture is then stirred at 200-300 r / min for 0.5-1.0 h to end-cap the product, thereby obtaining the rosin-based polyether intermediate. 3) Add industrial naphthalene and concentrated sulfuric acid to the enamel-lined reactor, start stirring at 150-250 r / min, heat to 150-160℃, sulfonate for 2.5-3.5 h, then cool to 130-140℃, add all deionized water, and stir at 200-300 r / min for 0.5-1.0 h. 4) Add 1 / 2-2 / 3 of the total mass of formaldehyde aqueous solution and 1 / 2-2 / 3 of the total mass of rosin-based polyether intermediate to the system obtained in step 3). Heat to 105-115℃ and stir at 200-300 r / min for 2.0-2.5 h. Then add the remaining formaldehyde aqueous solution and rosin-based polyether intermediate and continue stirring for 3.5-4.5 h. Finally, adjust the pH to 7.5-8.5 with a 28%-32% sodium hydroxide solution and dilute with deionized water to a solid content of 35%-45% to obtain the rosin polyether modified naphthalene sulfonate condensate.

[0012] Using the above technical solution, in step 1), nitrogen purging removes air from the reactor, reducing air interference with the reaction system. Vacuum dehydration removes moisture from the disproportionated rosin, creating suitable conditions for the subsequent reaction of ethylene oxide and disproportionated rosin. In step 2), ethylene oxide reacts with the dehydrated disproportionated rosin, and combined with glacial acetic acid neutralization and end-capping, a structurally stable rosin-based polyether intermediate is generated. In step 3), industrial naphthalene undergoes a sulfonation reaction with concentrated sulfuric acid, and subsequent addition of water and stirring hydrolyzes the sulfonation product, improving the reaction environment. In step 4), the condensation reaction is carried out by adding formaldehyde aqueous solution and rosin-based polyether intermediate in stages, which makes the condensation reaction more complete and the product structure more regular. Subsequent neutralization with sodium hydroxide solution and dilution with deionized water adjusts the pH and solid content of the product, ultimately yielding a rosin polyether-modified naphthalene sulfonate condensate.

[0013] Preferably, the rosin polyether modified naphthalene sulfonate condensate has a number average molecular weight of 18,000-22,000 Da and a degree of sulfonation of 1.8-2.4 mmol / g.

[0014] By adopting the above technical solution, the molecular chain length can be kept within a suitable range, which can ensure that the hydrophobic groups on the molecular chain form sufficient adsorption interactions with the coal particle surface, and avoid molecular entanglement caused by excessively long molecular chains, thereby maintaining good dispersion of molecules in the coal-water slurry system. The sulfonation degree of the rosin polyether modified naphthalene sulfonate condensate is controlled at 1.8-2.4 mmol / g, which can give the molecular chain an appropriate amount of sulfonic acid groups, provide sufficient negative charge for the molecules, enhance the adsorption capacity of molecules with the coal particle surface, and at the same time adjust the solubility of molecules in the aqueous phase, so that the rosin polyether modified naphthalene sulfonate condensate can play an effective dispersing role in the coal-water slurry system.

[0015] Preferably, the raw materials for preparing the borate ester dynamically crosslinked cellulose microgel, by weight, include: 4-8 parts hydroxyethyl cellulose, 2.5-4.5 parts phenylboronic acid, 1.5-3.0 parts cashew phenol polyoxyethylene ether, 1.2-2.5 parts 1,4-butanediol diglycidyl ether, 1.5-2.5 parts sorbitol, 80-100 parts acetone, 50-70 parts anhydrous ethanol, and 90-100 parts deionized water.

[0016] Using the above technical solution, hydroxyethyl cellulose, as the substrate of the boronic acid ester dynamically crosslinked cellulose microgel, can provide a large number of hydroxyl active sites, providing reaction sites for its subsequent crosslinking reaction; phenylboronic acid can undergo esterification reaction with the hydroxyl groups on the hydroxyethyl cellulose molecular chain to form boronic acid ester bonds, constructing a reversible dynamic crosslinking structure for the microgel; cashew phenol polyoxyethylene ether can introduce hydrophobic segments to adjust the hydrophobic properties of the microgel; 1,4-butanediol diglycidyl ether can undergo crosslinking reaction with hydroxyethyl cellulose to form a stable crosslinking backbone; sorbitol can participate in the construction of the crosslinking network and adjust the network structure of the microgel; acetone can be used as a precipitant to precipitate the microgel particles from the reaction system; anhydrous ethanol can be used to wash the microgel solid product to remove residual unreacted raw materials and by-products; deionized water, as the reaction medium, can fully dissolve and disperse the raw materials, providing a uniform environment for the reaction between the components and ensuring the smooth progress of the reaction between the components.

[0017] Preferably, the method for preparing the borate ester dynamically cross-linked cellulose microgel includes the following steps: (1) Heat deionized water to 65-75℃ and stir continuously at 200-300r / min. Add hydroxyethyl cellulose and stir until it is completely dissolved. Cool down to 40-50℃ and add cashew phenol polyoxyethylene ether and phenylboronic acid. Adjust the pH to 4.0-5.0 with 0.06-0.10mol / L hydrochloric acid solution and stir at 200-300r / min for 2.5-4.0h. (2) Adjust the pH of the system obtained in step (1) to 8.5-9.5 with a sodium hydroxide solution with a mass fraction of 28%-32%, stir continuously at a speed of 350-450 r / min, add 1,4-butanediol diglycidyl ether dropwise at a speed of 2-4 mL / min, and continue stirring for 1-2 h after the addition is complete. After cooling to 25-30℃, add sorbitol and stir at a speed of 200-300 r / min for 10-12 min, then add acetone and stir at a speed of 300-400 r / min for 10-15 min, and let it stand to precipitate for 30-40 min. (3) Filter the system obtained in step (2) with a 250-300 mesh filter, wash the obtained solid with anhydrous ethanol 2-3 times, place the washed precipitate in a vacuum drying oven, dry it for 14-18 hours at 40-50℃ and vacuum degree -0.08MPa~-0.095MPa, pulverize it, and obtain borate ester dynamically cross-linked cellulose microgel with an average particle size of 500-700nm.

[0018] Using the above technical solution, by controlling the reaction temperature, pH value, and stirring speed, hydroxyethyl cellulose is fully dissolved and dispersed in deionized water, providing a uniform reaction system for subsequent reactions. Cashew phenol polyoxyethylene ether, phenylboronic acid, and hydroxyethyl cellulose undergo a synergistic reaction under specific pH conditions, respectively achieving hydrophobic modification and borate esterification modification of hydroxyethyl cellulose. The dropwise addition reaction of 1,4-butanediol diglycidyl ether can form an etherified cross-linked structure with hydroxyethyl cellulose, sorbitol can participate in the formation of the cross-linked network, and acetone can fully precipitate the reaction products. Filtration can effectively separate the solid products from the liquid phase, anhydrous ethanol washing can remove residual unreacted raw materials, by-products, and solvents from the products, vacuum drying can remove residual solvents and free water from the products, and pulverization can obtain borate ester dynamically cross-linked cellulose microgels with specific particle sizes. The borate ester dynamically cross-linked cellulose microgels prepared by the above steps have a stable structure and uniform particle size.

[0019] This invention also discloses a method for preparing a naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, comprising the following steps: S1. Add 60%-75% of deionized water to the reaction vessel, heat to 40-50℃, stir continuously at 250-350r / min, add borate ester dynamic cross-linked cellulose microgel, keep warm and stir for 35-50min to obtain a uniformly dispersed gel suspension. S2. Keep the system obtained in step S1 at 40-50℃, and add rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate water-reducing agent in sequence, and stir at 300-400r / min for 60-80min. S3. Cool the system obtained in step S2 to 25-35℃, add isotridecyl alcohol polyoxyethylene ether, antifreeze and humectant, sodium gluconate, stir at 300-400 r / min for 35-50 min, add tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, stir at 300-400 r / min for 15-25 min, and stabilize the pH of the system at 8.0-8.5. S4. Add auxiliary stabilizer to the system obtained in step S3, stir at 100-180 r / min for 25-35 min, add the remaining deionized water and polyether modified polysiloxane, stir at 100-180 r / min for 20-30 min, then transfer the product to a curing tank, let it stand and cure at 25-30℃ for 14-18 h, filter, and obtain naphthalene sulfonate modified coal-water slurry dispersion stabilizer.

[0020] Using the above technical solution, through stepwise temperature control and gradient stirring, the dynamically cross-linked cellulose microgel of borate ester is fully swollen and dispersed in deionized water to form a uniform gel suspension. The rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate-based water-reducing agent are fully mixed at a suitable temperature to achieve synergistic effects among the dispersed components. The addition and stirring of isomeric tridecyl alcohol polyoxyethylene ether, antifreeze humectant, and sodium gluconate ensure uniform dispersion of all components in the system. The trimethylolaminomethane-hydrochloric acid buffer pair maintains the system pH within a stable range of 8.0-8.5. Subsequent addition and stirring of auxiliary stabilizers, residual deionized water, and polyether-modified polysiloxane improve the system composition and remove air bubbles. Subsequent static curing allows for further interaction among the components, and filtration removes impurities, ultimately yielding a uniform and stable naphthalene sulfonate modified coal-water slurry dispersion stabilizer.

[0021] Preferably, in step S4, the filter used for filtration is a 200-300 mesh stainless steel filter.

[0022] The above technical solution can effectively retain undispersed solid impurities and particulate agglomerates in the naphthalene sulfonate modified coal-water slurry dispersion stabilizer system; the stainless steel material is resistant to corrosion of the components in the system and is not prone to corrosion damage, which can ensure the stability and continuity of the filtration process; the filter screen in this mesh range can effectively retain impurities and ensure the purity of the finished product, while avoiding the decrease in filtration efficiency caused by excessively high filter screen mesh, ensuring that the finished naphthalene sulfonate modified coal-water slurry dispersion stabilizer maintains a uniform system state.

[0023] The present invention also discloses the application of a naphthalene sulfonate modified coal-water slurry dispersant stabilizer in the preparation of coal-water slurry, wherein the amount of the coal-water slurry dispersant stabilizer is 0.45%-0.55% of the dry coal mass.

[0024] Using the above technical solution, at this addition amount, each component in the dispersant stabilizer can fully exert its function and achieve a synergistic effect among the components; it can enable rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate water-reducing agent to form a stable adsorption layer on the surface of coal particles, while enabling borate ester dynamically cross-linked cellulose microgels to form a suitable three-dimensional network structure in the coal-water slurry system; at the same time, it can reasonably control the cost of using the dispersant stabilizer while ensuring the dispersion stability and low-temperature fluidity of the coal-water slurry, so that the prepared coal-water slurry maintains good comprehensive performance and process adaptability.

[0025] The beneficial effects of this invention are as follows: Rosin polyether-modified naphthalene sulfonate condensate can effectively disperse coal particles and improve the dispersion performance of coal-water slurry; boronic acid ester dynamically cross-linked cellulose microgels can enhance the stability of coal-water slurry and improve its thixotropic properties; auxiliary stabilizers can further improve the system stability of coal-water slurry; polycarboxylate superplasticizers and sulfonated lignin synergistically play an auxiliary dispersion role, enhancing the dispersion effect of coal particles; isomeric tridecyl alcohol polyoxyethylene ether can improve the wetting and penetration effect of coal particles and optimize the slurry's formability; antifreeze and humectant can lower the freezing point of the coal-water slurry system and maintain the rheological properties of the slurry at low temperatures; sodium gluconate can chelate metal ions in the slurry. It inhibits the destructive effect of metal ions on the dispersion and stabilization system; the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair can maintain the pH stability of the slurry system and ensure the normal function of each component; polyether-modified polysiloxane can inhibit foam generation during the preparation and use of coal-water slurry and improve the uniformity of the slurry; deionized water, as a solvent, provides a uniform reaction system for the dispersion and action of each component; the synergistic cooperation and complementary effects of each component result in a coal-water slurry dispersion stabilizer that can effectively regulate the rheological properties and stability of coal-water slurry, thereby meeting the various performance requirements of coal-water slurry raw materials in the process of biomass compacted fuel processing. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The specific information on the raw materials used in the embodiments of the present invention is shown in Table 1.

[0028] Table 1

[0029] Example 1: This embodiment discloses a naphthalene sulfonate modified coal-water slurry dispersion stabilizer. By weight, its preparation raw materials include: 22 parts of rosin polyether modified naphthalene sulfonate condensate, 1.5 parts of borate ester dynamically crosslinked cellulose microgel, 0.8 parts of auxiliary stabilizer, 5 parts of polycarboxylate water-reducing agent, 8 parts of sulfonated lignin, 0.8 parts of isomeric tridecyl alcohol polyoxyethylene ether, 5 parts of antifreeze and humectant, 2.5 parts of sodium gluconate, 0.4 parts of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, 0.15 parts of polyether modified polysiloxane, and 30 parts of deionized water.

[0030] The auxiliary stabilizer is xanthan gum, and the antifreeze and moisturizing agent is a compound of propylene glycol and sorbitol in a mass ratio of 4:1. Tris(hydroxymethyl)aminomethane-hydrochloric acid buffer is added in a 0.02 mol / L aqueous solution to make the pH of the naphthalenesulfonate modified coal-water slurry dispersion stabilizer system 8.0.

[0031] The raw materials for preparing rosin polyether modified naphthalene sulfonate condensate, by weight, include: 90 parts disproportionated rosin, 0.4 parts potassium hydroxide, 35 parts ethylene oxide, 90 parts industrial naphthalene, 130 parts concentrated sulfuric acid, 70 parts formaldehyde aqueous solution with a mass fraction of 35%, 20 parts deionized water, and 1 part glacial acetic acid.

[0032] The preparation method of rosin polyether modified naphthalene sulfonate condensate includes the following steps: 1) Add disproportionated rosin and potassium hydroxide to the high-pressure reactor, replace the air in the reactor with nitrogen until the oxygen content is ≤0.5%, start stirring at 200 r / min, raise the temperature to 145℃, maintain the vacuum at -0.085MPa, and keep it at the temperature for dehydration for 30 min; 2) Ethylene oxide was introduced into the system obtained in step 1), and the pressure was controlled at 0.45 MPa and the temperature at 155 °C. The mixture was stirred at 200 r / min for 3.5 h until the pressure was constant. The temperature was then lowered to 75 °C, and the pH was neutralized to 6.5 with glacial acetic acid. The mixture was stirred at 200 r / min for 0.5 h to end-cap the mixture, thus obtaining the rosin-based polyether intermediate. 3) Add industrial naphthalene and concentrated sulfuric acid to the enamel-lined reactor, start stirring at 150 r / min, heat to 150℃, sulfonate for 2.5 h, then cool to 130℃, add all deionized water, and stir at 200 r / min for 0.5 h. 4) Add half of the formaldehyde aqueous solution and half of the rosin-based polyether intermediate to the system obtained in step 3). Heat to 105°C and stir at 200 r / min for 2 h. Then add the remaining formaldehyde aqueous solution and rosin-based polyether intermediate and continue stirring for 3.5 h. Finally, adjust the pH to 7.5 with 28% sodium hydroxide solution and dilute with deionized water to a solid content of 35% to obtain a rosin polyether modified naphthalene sulfonate condensate with a number average molecular weight of 18000 Da and a sulfonation degree of 1.8 mmol / g.

[0033] The raw materials for preparing the dynamically cross-linked cellulose microgel by borate esters, by weight, include: 4 parts hydroxyethyl cellulose, 2.5 parts phenylboronic acid, 1.5 parts cashew phenol polyoxyethylene ether, 1.2 parts 1,4-butanediol diglycidyl ether, 1.5 parts sorbitol, 80 parts acetone, 50 parts anhydrous ethanol, and 90 parts deionized water.

[0034] The preparation method of dynamically cross-linked cellulose microgels with borate esters includes the following steps: (1) Heat deionized water to 65°C and stir continuously at 200 r / min. Add hydroxyethyl cellulose and stir until it is completely dissolved. Cool down to 40°C and add cashew phenol polyoxyethylene ether and phenylboronic acid. Adjust the pH to 4.0 with 0.06 mol / L hydrochloric acid solution and stir at 200 r / min for 2.5 h. (2) Adjust the pH of the system obtained in step (1) to 8.5 with a sodium hydroxide solution with a mass fraction of 28%, stir continuously at a speed of 350 r / min, add 1,4-butanediol diglycidyl ether dropwise at a speed of 2 mL / min, and continue stirring for 1 h after the addition is complete. After cooling to 25 °C, add sorbitol and stir at a speed of 200 r / min for 10 min. Then add acetone and stir at a speed of 300 r / min for 10 min. Let it stand to precipitate for 30 min. (3) The system obtained in step (2) was filtered with a 250-mesh filter, and the solid obtained was washed twice with anhydrous ethanol. The washed precipitate was placed in a vacuum drying oven and dried for 14 hours at 40°C and a vacuum of -0.08 MPa. The precipitate was then pulverized to obtain a borate ester dynamic cross-linked cellulose microgel with an average particle size of 500 nm.

[0035] This embodiment also discloses a method for preparing a naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, comprising the following steps: S1. Add 60% of the total amount of deionized water to the reactor, heat to 40°C, stir continuously at 250 r / min, add borate ester dynamic cross-linked cellulose microgel, keep warm and stir for 35 min to obtain a uniformly dispersed gel suspension. S2. Keep the system obtained in step S1 at 40°C, and add rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate superplasticizer in sequence, and stir at 300 r / min for 60 min. S3. Cool the system obtained in step S2 to 25°C, add isotridecyl alcohol polyoxyethylene ether, antifreeze and moisturizing agent, sodium gluconate, stir at 300 r / min for 35 min, add tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, stir at 300 r / min for 15 min, and stabilize the pH of the system at 8.0. S4. Add auxiliary stabilizer to the system obtained in step S3, stir at 100 r / min for 25 min, add the remaining deionized water and polyether modified polysiloxane, stir at 100 r / min for 20 min, then transfer the product to a curing tank, let it stand and cure at 25°C for 14 h, filter with a 200 mesh stainless steel filter to obtain naphthalene sulfonate modified coal-water slurry dispersion stabilizer.

[0036] This embodiment also discloses the application of a naphthalene sulfonate modified coal-water slurry dispersant stabilizer in the preparation of coal-water slurry, wherein the amount of the coal-water slurry dispersant stabilizer is 0.45% of the dry coal mass.

[0037] Example 2: This embodiment discloses a naphthalene sulfonate modified coal-water slurry dispersion stabilizer. By weight, its preparation raw materials include: 38 parts of rosin polyether modified naphthalene sulfonate condensate, 3.5 parts of borate ester dynamically crosslinked cellulose microgel, 2.0 parts of auxiliary stabilizer, 10 parts of polycarboxylate water-reducing agent, 15 parts of sulfonated lignin, 2.5 parts of isomeric tridecyl alcohol polyoxyethylene ether, 10 parts of antifreeze and moisturizing agent, 5 parts of sodium gluconate, 1 part of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, 0.6 parts of polyether modified polysiloxane, and 50 parts of deionized water.

[0038] The auxiliary stabilizer is a precipitant, and the antifreeze and moisturizing agent is a compound of propylene glycol and sorbitol in a mass ratio of 6:1. Tris(hydroxymethyl)aminomethane-hydrochloric acid buffer is added in a 0.06 mol / L aqueous solution to make the pH of the naphthalenesulfonate modified coal-water slurry dispersion stabilizer system 8.5.

[0039] The raw materials for preparing rosin polyether modified naphthalene sulfonate condensate, by weight, include: 100 parts disproportionated rosin, 0.8 parts potassium hydroxide, 60 parts ethylene oxide, 100 parts industrial naphthalene, 150 parts concentrated sulfuric acid, 100 parts formaldehyde aqueous solution with a mass fraction of 37%, 30 parts deionized water, and 2 parts glacial acetic acid.

[0040] The preparation method of rosin polyether modified naphthalene sulfonate condensate includes the following steps: 1) Add disproportionated rosin and potassium hydroxide to the high-pressure reactor, replace the air in the reactor with nitrogen until the oxygen content is ≤0.5%, start stirring at 300 r / min, raise the temperature to 165℃, maintain the vacuum at -0.095MPa, and keep it at the temperature for 45 min for dehydration. 2) Ethylene oxide is introduced into the system obtained in step 1), the pressure is controlled at 0.55 MPa and the temperature at 175 °C, and the reaction is stirred at 300 r / min for 5 h until the pressure is constant. The temperature is then lowered to 85 °C, and the pH is neutralized to 7.5 with glacial acetic acid. The reaction is then stirred at 300 r / min for 1 h to end-cap the rosin-based polyether intermediate. 3) Add industrial naphthalene and concentrated sulfuric acid to the enamel-lined reactor, start stirring at 250 r / min, heat to 160℃, sulfonate for 3.5 h, then cool to 140℃, add all deionized water, and stir at 300 r / min for 1 h. 4) Add 2 / 3 of the total mass of formaldehyde aqueous solution and 2 / 3 of the total mass of rosin-based polyether intermediate to the system obtained in step 3). Heat to 115°C and stir at 300 r / min for 2.5 h. Then add the remaining formaldehyde aqueous solution and rosin-based polyether intermediate and continue stirring for 4.5 h. Finally, adjust the pH to 8.5 with 32% sodium hydroxide solution and dilute with deionized water to a solid content of 45% to obtain a rosin polyether modified naphthalene sulfonate condensate with a number average molecular weight of 22000 Da and a sulfonation degree of 2.4 mmol / g.

[0041] The raw materials for preparing the borate ester dynamically crosslinked cellulose microgel, by weight, include: 8 parts hydroxyethyl cellulose, 4.5 parts phenylboronic acid, 3.0 parts cashew phenol polyoxyethylene ether, 2.5 parts 1,4-butanediol diglycidyl ether, 2.5 parts sorbitol, 100 parts acetone, 70 parts anhydrous ethanol, and 100 parts deionized water.

[0042] The preparation method of dynamically cross-linked cellulose microgels with borate esters includes the following steps: (1) Heat deionized water to 75°C, stir continuously at 300 r / min, add hydroxyethyl cellulose, stir until it is completely dissolved, cool down to 50°C, add cashew phenol polyoxyethylene ether and phenylboronic acid, adjust pH to 5.0 with 0.1 mol / L hydrochloric acid solution, stir at 300 r / min for 4 h. (2) Adjust the pH of the system obtained in step (1) to 9.5 with a 32% sodium hydroxide solution. Stir continuously at 450 r / min and add 1,4-butanediol diglycidyl ether dropwise at 4 mL / min. After the addition is complete, continue stirring for 2 h. After cooling to 30°C, add sorbitol and stir at 300 r / min for 12 min. Then add acetone and stir at 400 r / min for 15 min. Let it stand to precipitate for 40 min. (3) The system obtained in step (2) was filtered with a 300-mesh filter, and the solid obtained was washed three times with anhydrous ethanol. The washed precipitate was placed in a vacuum drying oven and dried for 18 hours at 50°C and a vacuum of -0.095 MPa. The precipitate was then pulverized to obtain a borate ester dynamic cross-linked cellulose microgel with an average particle size of 700 nm.

[0043] This embodiment also discloses a method for preparing a naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, comprising the following steps: S1. Add 75% of the total amount of deionized water to the reactor, heat to 50°C, stir continuously at 350 r / min, add borate ester dynamic cross-linked cellulose microgel, keep warm and stir for 50 min to obtain a uniformly dispersed gel suspension. S2. Keep the system obtained in step S1 at 50°C, and add rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate superplasticizer in sequence, and stir at 400 r / min for 80 min. S3. Cool the system obtained in step S2 to 35°C, add isotridecyl alcohol polyoxyethylene ether, antifreeze and moisturizing agent, sodium gluconate, stir at 400 r / min for 50 min, add tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, stir at 400 r / min for 25 min, and stabilize the pH of the system at 8.5. S4. Add auxiliary stabilizer to the system obtained in step S3, stir at 180 r / min for 35 min, add the remaining deionized water and polyether modified polysiloxane, stir at 180 r / min for 30 min, then transfer the product to a curing tank, let it stand and cure at 30°C for 18 h, filter with a 300 mesh stainless steel filter to obtain naphthalene sulfonate modified coal-water slurry dispersion stabilizer.

[0044] This embodiment also discloses the application of a naphthalene sulfonate modified coal-water slurry dispersant stabilizer in the preparation of coal-water slurry, wherein the amount of the coal-water slurry dispersant stabilizer is 0.55% of the dry coal mass.

[0045] Example 3: This embodiment discloses a naphthalene sulfonate modified coal-water slurry dispersion stabilizer. By weight, its preparation raw materials include: 30 parts of rosin polyether modified naphthalene sulfonate condensate, 2.5 parts of borate ester dynamically crosslinked cellulose microgel, 1.4 parts of auxiliary stabilizer, 7 parts of polycarboxylic acid water-reducing agent, 11 parts of sulfonated lignin, 1.6 parts of isomeric tridecyl alcohol polyoxyethylene ether, 7 parts of antifreeze and humectant, 4 parts of sodium gluconate, 0.7 parts of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, 0.4 parts of polyether modified polysiloxane, and 40 parts of deionized water.

[0046] The auxiliary stabilizer is xanthan gum, and the antifreeze and moisturizing agent is a compound of propylene glycol and sorbitol in a mass ratio of 5:1. Tris(hydroxymethyl)aminomethane-hydrochloric acid buffer is added in a 0.04 mol / L aqueous solution to make the pH of the naphthalenesulfonate modified coal-water slurry dispersion stabilizer system 8.2.

[0047] The raw materials for preparing rosin polyether modified naphthalene sulfonate condensate, by weight, include: 95 parts disproportionated rosin, 0.6 parts potassium hydroxide, 45 parts ethylene oxide, 95 parts industrial naphthalene, 140 parts concentrated sulfuric acid, 85 parts formaldehyde aqueous solution with a mass fraction of 36%, 25 parts deionized water, and 1.5 parts glacial acetic acid.

[0048] The preparation method of rosin polyether modified naphthalene sulfonate condensate includes the following steps: 1) Add disproportionated rosin and potassium hydroxide to the high-pressure reactor, replace the air in the reactor with nitrogen until the oxygen content is ≤0.5%, start stirring at 250 r / min, raise the temperature to 155℃, maintain the vacuum at -0.090 MPa, and keep it at the temperature for dehydration for 38 min. 2) Ethylene oxide was introduced into the system obtained in step 1), and the pressure was controlled at 0.5 MPa and the temperature at 165 °C. The mixture was stirred at 250 r / min for 4 h until the pressure was constant. The temperature was then lowered to 80 °C, and the pH was neutralized to 7.0 with glacial acetic acid. The mixture was stirred at 250 r / min for 0.8 h to end-cap the mixture, thus obtaining the rosin-based polyether intermediate. 3) Add industrial naphthalene and concentrated sulfuric acid to the enamel-lined reactor, start stirring at 200 r / min, heat to 155℃, sulfonate for 3 h, then cool to 135℃, add all deionized water, and stir at 250 r / min for 1 h. 4) Add 2 / 3 of the total mass of formaldehyde aqueous solution and 2 / 3 of the total mass of rosin-based polyether intermediate to the system obtained in step 3). Heat to 110°C and stir at 250 r / min for 2.5 h. Then add the remaining formaldehyde aqueous solution and rosin-based polyether intermediate and continue stirring for 4 h. Finally, adjust the pH to 8.0 with 30% sodium hydroxide solution and dilute with deionized water to a solid content of 40% to obtain a rosin polyether modified naphthalene sulfonate condensate with a number average molecular weight of 20000 Da and a sulfonation degree of 2.1 mmol / g.

[0049] The raw materials for preparing the dynamically cross-linked cellulose microgel by borate esters, by weight, include: 6 parts hydroxyethyl cellulose, 3.5 parts phenylboronic acid, 2.2 parts cashew phenol polyoxyethylene ether, 1.8 parts 1,4-butanediol diglycidyl ether, 2 parts sorbitol, 90 parts acetone, 60 parts anhydrous ethanol, and 95 parts deionized water.

[0050] The preparation method of dynamically cross-linked cellulose microgels with borate esters includes the following steps: (1) Heat deionized water to 70°C and stir continuously at 250 r / min. Add hydroxyethyl cellulose and stir until it is completely dissolved. Cool down to 45°C and add cashew phenol polyoxyethylene ether and phenylboronic acid. Adjust the pH to 4.5 with 0.08 mol / L hydrochloric acid solution and stir at 250 r / min for 3 h. (2) Adjust the pH of the system obtained in step (1) to 9.0 with a 30% sodium hydroxide solution. Stir continuously at 400 r / min and add 1,4-butanediol diglycidyl ether dropwise at 3 mL / min. After the addition is complete, continue stirring for 1.5 h. After cooling to 28 °C, add sorbitol and stir at 250 r / min for 11 min. Then add acetone and stir at 350 r / min for 12 min. Let it stand to precipitate for 35 min. (3) The system obtained in step (2) was filtered with a 275-mesh filter, and the solid obtained was washed three times with anhydrous ethanol. The washed precipitate was placed in a vacuum drying oven and dried for 16 hours at 45°C and a vacuum of -0.088 MPa. The precipitate was then pulverized to obtain a borate ester dynamic cross-linked cellulose microgel with an average particle size of 600 nm.

[0051] This embodiment also discloses a method for preparing a naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, comprising the following steps: S1. Add 68% of the total amount of deionized water to the reactor, heat to 45°C, stir continuously at 300 r / min, add borate ester dynamic cross-linked cellulose microgel, keep warm and stir for 45 min to obtain a uniformly dispersed gel suspension. S2. Keep the system obtained in step S1 at 45°C, and add rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate superplasticizer in sequence, and stir at 350 r / min for 70 min. S3. Cool the system obtained in step S2 to 30°C, add isotridecyl alcohol polyoxyethylene ether, antifreeze and moisturizing agent, sodium gluconate, stir at 350 r / min for 45 min, add tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, stir at 350 r / min for 20 min, and stabilize the pH of the system at 8.2. S4. Add auxiliary stabilizer to the system obtained in step S3, stir at 140 r / min for 30 min, add the remaining deionized water and polyether modified polysiloxane, stir at 140 r / min for 25 min, then transfer the product to a curing tank, let it stand and cure at 28°C for 16 h, filter with a 250 mesh stainless steel filter to obtain naphthalene sulfonate modified coal-water slurry dispersion stabilizer.

[0052] This embodiment also discloses the application of a naphthalene sulfonate modified coal-water slurry dispersant stabilizer in the preparation of coal-water slurry, wherein the amount of the coal-water slurry dispersant stabilizer is 0.5% of the dry coal mass.

[0053] Comparative Example 1: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: no rosin polyether modified naphthalene sulfonate condensate condensate is added, and it is replaced by an equal amount of β-naphthalene sulfonate sodium formaldehyde condensate (purity 98%, purchased from Guangzhou Yuanda New Materials Co., Ltd., CAS: 26545-58-4).

[0054] Comparative Example 2: A naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: no borate ester dynamically crosslinked cellulose microgel is added, and hydroxyethyl cellulose is replaced in equal amounts.

[0055] Comparative Example 3: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: no polycarboxylate superplasticizer is added.

[0056] Comparative Example 4: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: no sulfonated lignin is added.

[0057] Comparative Example 5: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: cashew phenol polyoxyethylene ether is not added to the raw materials for preparing borate ester dynamic crosslinked cellulose microgel.

[0058] Comparative Example 6: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair is replaced by an equal amount of phosphate buffer pair (disodium hydrogen phosphate-sodium dihydrogen phosphate, pH 8.2, purchased from Shanghai Chuangsai Technology Co., Ltd.).

[0059] Comparative Example 7: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that sodium gluconate is not added.

[0060] Comparative Example 8: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: in the preparation method of the naphthalene sulfonate modified coal-water slurry dispersion stabilizer, all raw materials are mixed at 25°C in one go, without gradient temperature control of S1-S4.

[0061] Comparative Example 9: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: the boronic acid ester dynamically crosslinked cellulose microgel is replaced in equal amounts with carboxymethyl cellulose (purity 99%, purchased from Hubei Chengfeng Chemical Co., Ltd., CAS: 9000-11-7).

[0062] Comparative Example 10: A naphthalene sulfonate modified coal-water slurry dispersion stabilizer, its preparation method and application, differs from Example 3 only in that: the antifreeze and moisturizing agent uses only propylene glycol and no sorbitol is added.

[0063] The dispersants and stabilizers obtained in Examples 1-3 and Comparative Examples 1-10 were prepared into coal-water slurry according to the following methods and their relevant performance was tested. (I) Preparation of coal-water slurry Shaanxi Shenmu bituminous coal (air-dried basis, moisture content M) was used. a d=8.2%, air-dried basis ash A a (d=7.5%, grindability index HGI=65), crush and grind to a particle size ≤0.074mm, accounting for ≥80%. Add dispersant and stabilizer at 0.5% of dry coal mass, add water to adjust, stir at high speed (1200r / min) for 10min in a rod mill, stir at low speed (500r / min) for 5min, let stand for 10min to defoam, and then set aside for use.

[0064] (II) Testing Items and Methods Coal-water slurry concentration determination: The test was conducted according to GB / T 18856.2-2008 Test Methods for Coal-Water Slurry Part 2: Determination of Concentration. A rapid drying method was used; approximately 3g of sample was weighed and dried in a drying oven at 105±2℃ until constant weight, and the solid content was calculated.

[0065] Apparent viscosity measurement: The test was conducted according to GB / T 18856.4-2008 Water-coal slurry test methods – Part 4: Determination of apparent viscosity. An NXS-4C rotational viscometer was used at 25±0.5℃ and a shear rate of 100 s⁻¹. -1 The measurement was performed under the specified conditions, and the reading was recorded after it stabilized. The unit is mPa·s.

[0066] Low-temperature viscosity change rate determination: The prepared coal-water slurry was stored in a constant temperature chamber at -10±1℃ for 24 hours. Immediately after removal, the viscosity η was measured on the same viscometer. -10 ℃, and initial viscosity η 25 Compare temperatures by ℃, and calculate using the formula: Low-temperature viscosity change rate = [(η -10 ℃-η 25 ℃ / η 25 ℃]×100% Static stability test: The test was conducted according to GB / T 18856.5-2008 Test Methods for Coal-Water Slurry Part 5: Stability Determination. 100 mL of coal-water slurry was poured into a 100 mL graduated cylinder and allowed to stand at room temperature for 7 days. The percentage of the upper layer of water separation relative to the total height of the slurry was measured as the water separation rate. A 6 mm diameter glass rod was dropped through the slurry under its own weight, and the time from the surface to the bottom was recorded as the drop time. The presence of hard sediment at the bottom was observed.

[0067] Inorganic salt content determination: The test was conducted using ion chromatography as specified in GB / T 8077-2012, "Test Method for Homogeneity of Concrete Admixtures". After drying the dispersion stabilizer sample, it was dissolved in deionized water, and the Na+ content was determined. + K + SO4 2- Content, converted to sodium sulfate equivalent mass fraction.

[0068] Storage stability and structural retention determination: The dispersion stabilizer sample was stored in a 5℃ incubator for 6 months, and the appearance changes were observed. The structure retention rate was calculated by measuring the ratio of the static yield stress of the dynamically cross-linked cellulose microgels before and after storage. Structural retention rate = (τ)6month / τ0)×100% Where τ0 is the initial static yield stress, τ 6month To determine the static yield stress after 6 months of storage, a rheometer was used at 25°C and a shear rate of 0.1 s⁻¹. -1 Determined under the specified conditions.

[0069] COD emission load determination: conducted according to "HJ 828-2017 Determination of Chemical Oxygen Demand in Water - Dichromate Method", unit is mg / L.

[0070] The results are shown in Tables 2 and 3.

[0071] Table 2. Test results of basic properties of coal-water slurry

[0072] Table 3. Properties and long-term stability of the additives

[0073] Note: Static yield stress and structural retention rate are characteristic performance indicators of borate ester dynamically cross-linked cellulose microgels, used to quantify the thixotropic properties and long-term storage stability of the microgels, respectively. Comparative Examples 2 and 9 lack the dynamic cross-linked network structure due to the absence of borate ester dynamically cross-linked cellulose microgels, therefore this indicator is marked as "—" (not applicable).

[0074] Using Example 3 as the control group, the performance differences and causes of Comparative Examples 1-10 are analyzed as follows: Comparative Example 1: Naphthalene sulfonate condensate without rosin polyether was replaced with an equal weight of commercially available sodium β-naphthalene sulfonate formaldehyde condensate. The concentration of the coal-water slurry decreased from 68.2 wt% to 64.5 wt% (a decrease of 5.4%), the apparent viscosity at 25℃ increased from 880 mPa·s to 1120 mPa·s (an increase of 27.3%), the viscosity change rate at -10℃ increased from 9.5% to 16.8% (an increase of 76.8%), the 7-day water separation rate increased from 1.1% to 3.2% (an increase of 190.9%), the hard sedimentation rate increased from 0 to 2.8%, and the drop time increased from 3 s to 14 s (an increase of 366.7%). The inorganic salt content of the dispersant stabilizer increased from 6.8 wt% to 11.5 wt% (an increase of 69.1%), a small amount of sediment appeared at the bottom after 6 months of storage at 5℃, and the COD emission load increased from 550 mg / L to 950 mg / L (an increase of 72.7%). Commercially available sodium β-naphthalenesulfonate formaldehyde condensate lacks a rosin-based phenanthrene ring framework, making it unable to form strong π-π stacking and hydrophobic association with the hydrophobic aromatic layer on the surface of coal particles. This results in weak anchoring force with the coal particle surface, making it difficult to form a stable adsorption layer. Consequently, the dispersibility, concentration, and viscosity of the coal-water slurry decrease. Furthermore, lacking a polyether segment structure, it cannot form intermolecular hydrogen-bonded complexes with antifreeze and humectants, easily desorbing from the coal particle surface at low temperatures, causing dispersion failure and a significant increase in the low-temperature viscosity change rate. In addition, the commercially available product has a high inorganic salt content, which easily leads to uneven charge distribution on the coal particle surface, exacerbating particle agglomeration, resulting in hard precipitation, increased water separation rate, and component precipitation during storage. Moreover, the high content of organic pollutants significantly increases the COD emission load.

[0075] Comparative Example 2: Dynamically cross-linked cellulose microgels without borate esters were replaced with an equal weight of ordinary hydroxyethyl cellulose. The concentration of the coal-water slurry decreased from 68.2 wt% to 65.5 wt% (a decrease of 3.9%), the apparent viscosity at 25℃ increased from 880 mPa·s to 1020 mPa·s (an increase of 15.9%), the 7-day water separation rate increased from 1.1% to 3.8% (an increase of 245.5%), and the drop time increased from 3 s to 8 s (an increase of 166.7%). Ordinary hydroxyethyl cellulose is a linear molecule and cannot form a dynamic, reversible three-dimensional weak network structure of borate esters. It has no thixotropic properties and cannot provide sufficient yield stress support for the slurry under static conditions. Coal particles are prone to sedimentation, resulting in a significant increase in water separation rate and a prolonged drop time. At the same time, linear molecules lack ether bonds to stabilize the skeleton and cannot form a synergistic interfacial structure with the dispersant. This results in a weak steric stabilization effect on coal particles, leading to a slight decrease in slurry dispersibility, manifested as a slight decrease in concentration and a slight increase in viscosity. However, the hydrophilicity and thickening properties of ordinary hydroxyethyl cellulose can still maintain the slurry without hard sedimentation, and its inorganic salt content is similar to that of Example 3. Therefore, there is no significant change in COD emission load.

[0076] Comparative Example 3: No polycarboxylate superplasticizer added The concentration of the coal-water slurry decreased from 68.2 wt% to 66.8 wt% (a decrease of 2.1%), the apparent viscosity at 25℃ increased from 880 mPa·s to 995 mPa·s (an increase of 13.1%), the 7-day water separation rate increased from 1.1% to 2.0% (an increase of 81.8%), the hard sedimentation rate increased from 0 to 0.5%, and the drop time increased from 3 s to 6 s (an increase of 100%). The polycarboxylate superplasticizer has a comb-like molecular structure, and its side chains can further disperse coal particle agglomerates through steric hindrance. It forms a synergistic dispersant system with rosin polyether-modified naphthalene sulfonate condensate and sulfonated lignin, improving dispersion efficiency. The absence of this component weakens the steric hindrance effect of the dispersion system, slightly increases the degree of coal particle agglomeration, leading to a slight decrease in coal-water slurry concentration, an increase in viscosity, a decrease in slurry stability, slight hard sedimentation, and an increase in water separation rate. Because the polycarboxylate superplasticizer is not a core stabilizing component, the changes in various performance indicators are smaller compared to other key comparative examples.

[0077] Comparative Example 4: No sulfonated lignin added The concentration of the coal-water slurry decreased from 68.2 wt% to 66.5 wt% (a decrease of 2.5%), the 7-day water separation rate increased from 1.1% to 2.3% (an increase of 109.1%), and the hard sedimentation rate increased from 0 to 0.6%. Sulfonated lignin is a natural high-molecular-weight dispersant. Its sulfonated groups can adsorb onto the surface of coal particles to provide electrostatic repulsion. At the same time, it forms intermolecular synergistic adsorption with the rosin polyether modified naphthalene sulfonate condensate, supplementing the electrostatic stabilizing effect of the dispersion system. After the absence of this component, the electrostatic repulsion on the surface of coal particles weakens, slightly aggravates particle agglomeration, resulting in a slight decrease in the concentration of the coal-water slurry, an increase in the water separation rate, and the formation of a small amount of hard sedimentation. Since the dispersing effect of sulfonated lignin can be partially replaced by the main dispersant, the apparent viscosity at 25℃ and the low-temperature viscosity change rate do not change significantly.

[0078] Comparative Example 5: No cashew phenol polyoxyethylene ether was added to the raw materials for the preparation of dynamically cross-linked cellulose microgels containing borate esters. The apparent viscosity of the coal-water slurry at 25℃ increased from 880 mPa·s to 965 mPa·s (an increase of 9.7%), the water separation rate at 7 days increased from 1.1% to 2.5% (an increase of 127.3%), the hard sedimentation rate increased from 0 to 0.4%, and the drop time increased from 3s to 6s (an increase of 100%). The static yield stress of the dynamically cross-linked cellulose microgel of borate ester decreased from 35 Pa to 32 Pa (a decrease of 8.6%), and the structure retention rate after 6 months of storage at 5℃ decreased from 88% to 68% (a decrease of 22.7%). The dispersant stabilizer showed slight stratification and a small amount of flocculation. The hydrophobic segments of cashew phenol polyoxyethylene ether can coat the borate ester crosslinking points through hydrophobic association, forming hydrophobic microdomains, reducing local water activity, and slowing down the exchange rate of borate ester bonds from a kinetic perspective, so that the dynamic network can maintain dynamic equilibrium during storage. When this component is missing, the exchange rate of borate ester bonds accelerates, and irreversible reorganization of the network structure is prone to occur during storage, resulting in a decrease in the static yield stress of the microgel, a significant decrease in the structure retention rate, and a weakening of thixotropic properties and long-term stability. At the same time, the supporting effect of the dynamic network in the slurry is insufficient, the coal particle settling tendency is aggravated, which is manifested as increased viscosity, increased water separation rate, and slight hard precipitation. The dispersant stabilizer may also show slight stratification due to microgel flocculation.

[0079] Comparative Example 6: Using a phosphate buffer pair instead of a tris(hydroxymethyl)aminomethane-hydrochloride buffer pair After 6 months of storage at 5°C, the structure retention rate of dynamically cross-linked cellulose microgels containing borate esters decreased from 88% to 72% (a decrease of 18.2%). Although the phosphate buffer pair can maintain the pH of the system at around 8.0, its high ionic strength can interfere with the dynamic equilibrium of the borate ester bonds and reduce the binding stability between the borate ester groups and hydroxyl groups. In contrast, the amino group of tris(hydroxymethyl)aminomethane can form a weak coordination bond with boric acid, moderately stabilizing the borate ester bonds, slowing down their exchange rate, and ensuring the long-term stability of the dynamic network. The phosphate buffer pair lacks this coordination stabilizing effect, resulting in damage to the integrity of the network structure and a decrease in structure retention rate during the storage of the microgel. Since the phosphate buffer pair can still effectively prevent the reversal of surface charge on coal particles, the concentration, viscosity, and water separation rate of the coal-water slurry did not change significantly.

[0080] Comparative Example 7: No sodium gluconate added The apparent viscosity of the coal-water slurry at 25℃ increased from 880 mPa·s to 1185 mPa·s (an increase of 34.7%), the 7-day water separation rate increased from 1.1% to 4.0% (an increase of 263.6%), the hard sedimentation rate increased from 0 to 1.6%, and the drop time increased from 3 s to 11 s (an increase of 266.7%). The inorganic salt content of the dispersant stabilizer increased from 6.8 wt% to 8.5 wt% (an increase of 25.0%), and the COD emission load increased from 550 mg / L to 720 mg / L (an increase of 30.9%). Sodium gluconate, as a chelating stabilizer, can chelate trace metal ions in the slurry, preventing the metal ions from complexing with borate ester groups and sulfonated groups, thus preventing the deactivation of functional groups. At the same time, it can reduce the concentration of free ions in the system and reduce the interference of ionic strength on the dispersion and stabilization system. When this component is missing, metal ions complex with the sulfonated groups of the dispersant and the borate ester groups of the microgel, resulting in a significant decrease in the adsorption capacity of the main dispersant and the dynamic cross-linking capacity of the microgel. The adsorption layer on the surface of coal particles is incomplete, and particle agglomeration is severe. Therefore, the viscosity of the coal-water slurry increases sharply, the stability decreases significantly, and a large amount of hard precipitate appears. At the same time, the unchelated metal ions increase the inorganic salt content of the system and increase the degradation products of organic functional components, leading to an increase in COD emission load.

[0081] Comparative Example 8: The preparation process was changed to one-step mixing, without gradient temperature control and stepwise compounding. The concentration of the coal-water slurry decreased from 68.2 wt% to 65.5 wt% (a decrease of 3.9%), the apparent viscosity at 25℃ increased from 880 mPa·s to 1150 mPa·s (an increase of 30.7%), the viscosity change rate at -10℃ increased from 9.5% to 12.8% (an increase of 34.7%), the water separation rate at 7 days increased from 1.1% to 3.0% (an increase of 172.7%), the hard sedimentation rate increased from 0 to 2.2%, and the drop time increased from 3 s to 13 s (an increase of 333.3%). Slight stratification of the dispersant stabilizer was observed. The gradient temperature control and stepwise compounding process of this invention can achieve the orderly action of each component: the pre-swelling step ensures that the microgel fully swells to form a uniform colloid, the main dispersant compounding step enables the full interaction of each dispersant to form a synergistic system, the functional additive synergistic step ensures the precise control of the buffer system, chelating agent, antifreeze and moisturizing agent, etc., and the auxiliary stabilizer compounding step avoids mutual interference between components; under the one-step mixing process, each component comes into contact at the same time, the microgel cannot fully swell, the synergistic adsorption effect between dispersants is not fully formed, the buffer system cannot accurately control the pH, and mutual interference will occur between functional components, resulting in the overall failure of the dispersion and stabilization system. Therefore, all performance indicators of coal-water slurry deteriorate significantly, and the dispersion and stabilizer shows slight stratification due to uneven component dispersion.

[0082] Comparative Example 9: Dynamic cross-linking of cellulose microgels using carboxymethyl cellulose instead of borate esters The apparent viscosity of the coal-water slurry at 25℃ increased from 880 mPa·s to 1185 mPa·s (an increase of 34.7%), the viscosity change rate at -10℃ increased from 9.5% to 13.2% (an increase of 38.9%), the water separation rate at 7 days increased from 1.1% to 4.8% (an increase of 336.4%), the hard sedimentation rate increased from 0 to 1.8%, and the drop time increased from 3s to 15s (an increase of 400%). The static yield stress of carboxymethyl cellulose was only 15 Pa, and it had no dynamic cross-linked network structure, so there was no structure retention rate index. Carboxymethyl cellulose is a low molecular weight linear polysaccharide without a dynamic reversible cross-linked network structure. Its static yield stress is much lower than that of cellulose microgels with dynamic cross-linking of borate esters, which cannot provide sufficient thixotropic support for the slurry. Under low shear, the slurry viscosity is insufficient, and coal particles are prone to severe sedimentation, resulting in a significant increase in water separation rate, increased hard precipitation, and significantly prolonged drop time. At the same time, it lacks hydrophobic modifying groups, has weak interaction with the surface of coal particles, and cannot form a synergistic interfacial structure with the main dispersant. Furthermore, molecular entanglement can cause a sharp increase in the overall viscosity of the slurry. It also cannot form an effective network to inhibit ice crystal growth at low temperatures, thus increasing the viscosity change rate at low temperatures.

[0083] Comparative Example 10: The antifreeze moisturizer uses only propylene glycol and does not contain sorbitol. The viscosity change rate of coal-water slurry at -10℃ increased from 9.5% to 13.5% (an increase of 42.1%). Propylene glycol is a single antifreeze component, which can only achieve the antifreeze effect by lowering the freezing point of the system. However, the polyhydroxy structure of sorbitol can form a hydrogen bond network with polyether segments and water molecules, changing the arrangement of water molecules at low temperatures, inhibiting the growth and aggregation of ice crystal networks, and forming a synergistic antifreeze effect with propylene glycol. When only propylene glycol is used, ice crystal networks are easily formed at low temperatures. The mechanical action of ice crystals and the phase separation effect of water molecules destroy the adsorption layer on the surface of coal particles, resulting in an increase in slurry viscosity, hence the significant increase in the viscosity change rate at low temperatures. Since propylene glycol can still effectively lower the freezing point of the system, and sorbitol is not a core dispersing and stabilizing component, the concentration, viscosity, and water separation rate of coal-water slurry at room temperature do not change significantly.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A naphthalene sulfonate-modified coal-water slurry dispersion stabilizer, characterized in that, The raw materials for its preparation, by weight, include: 22-38 parts of rosin polyether modified naphthalene sulfonate condensate, 1.5-3.5 parts of borate ester dynamically cross-linked cellulose microgel, 0.8-2.0 parts of auxiliary stabilizer, 5-10 parts of polycarboxylate water-reducing agent, 8-15 parts of sulfonated lignin, 0.8-2.5 parts of isomeric tridecyl alcohol polyoxyethylene ether, 5-10 parts of antifreeze and moisturizing agent, 2.5-5 parts of sodium gluconate, 0.4-1.0 parts of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, 0.15-0.6 parts of polyether modified polysiloxane, and 30-50 parts of deionized water.

2. The naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 1, characterized in that, The auxiliary stabilizer is either xanthan gum or sorbitol; the antifreeze and moisturizing agent is a compound of propylene glycol and sorbitol in a mass ratio of 4:1-6:1; the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer is added in an aqueous solution of 0.02-0.06 mol / L, and the pH of the naphthalenesulfonate modified coal-water slurry dispersion stabilizer system is 8.0-8.

5.

3. The naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 1, characterized in that, The raw materials for preparing the rosin polyether modified naphthalene sulfonate condensate, by weight, include: 90-100 parts of disproportionated rosin, 0.4-0.8 parts of potassium hydroxide, 35-60 parts of ethylene oxide, 90-100 parts of industrial naphthalene, 130-150 parts of concentrated sulfuric acid, 70-100 parts of a 35%-37% formaldehyde aqueous solution, 20-30 parts of deionized water, and 1-2 parts of glacial acetic acid.

4. The naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 3, characterized in that, The preparation method of the rosin polyether modified naphthalene sulfonate condensate includes the following steps: 1) Add disproportionated rosin and potassium hydroxide to the high-pressure reactor, replace the air in the reactor with nitrogen until the oxygen content is ≤0.5%, start stirring at 200-300 r / min, raise the temperature to 145-165℃, maintain the vacuum at -0.085MPa~-0.095MPa, and keep it at the temperature for dehydration for 30-45 min; 2) Ethylene oxide is introduced into the system obtained in step 1), and the pressure is controlled at 0.45-0.55 MPa and the temperature at 155-175℃. The mixture is stirred at 200-300 r / min for 3.5-5 h until the pressure is constant. The temperature is then lowered to 75-85℃, and the pH is neutralized with glacial acetic acid to 6.5-7.

5. The mixture is then stirred at 200-300 r / min for 0.5-1.0 h to end-cap the product, thereby obtaining the rosin-based polyether intermediate. 3) Add industrial naphthalene and concentrated sulfuric acid to the enamel-lined reactor, start stirring at 150-250 r / min, heat to 150-160℃, sulfonate for 2.5-3.5 h, then cool to 130-140℃, add all deionized water, and stir at 200-300 r / min for 0.5-1.0 h. 4) Add 1 / 2-2 / 3 of the total mass of formaldehyde aqueous solution and 1 / 2-2 / 3 of the total mass of rosin-based polyether intermediate to the system obtained in step 3). Heat to 105-115℃ and stir at 200-300 r / min for 2.0-2.5 h. Then add the remaining formaldehyde aqueous solution and rosin-based polyether intermediate and continue stirring for 3.5-4.5 h. Finally, adjust the pH to 7.5-8.5 with a 28%-32% sodium hydroxide solution and dilute with deionized water to a solid content of 35%-45% to obtain the rosin polyether modified naphthalene sulfonate condensate.

5. The naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 4, characterized in that, The rosin polyether modified naphthalene sulfonate condensate has a number average molecular weight of 18,000-22,000 Da and a degree of sulfonation of 1.8-2.4 mmol / g.

6. The naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 1, characterized in that, The raw materials for preparing the borate ester dynamically crosslinked cellulose microgel, by weight, include: 4-8 parts hydroxyethyl cellulose, 2.5-4.5 parts phenylboronic acid, 1.5-3.0 parts cashew phenol polyoxyethylene ether, 1.2-2.5 parts 1,4-butanediol diglycidyl ether, 1.5-2.5 parts sorbitol, 80-100 parts acetone, 50-70 parts anhydrous ethanol, and 90-100 parts deionized water.

7. The naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 6, characterized in that, The preparation method of the borate ester dynamically cross-linked cellulose microgel includes the following steps: (1) Heat deionized water to 65-75℃ and stir continuously at 200-300r / min. Add hydroxyethyl cellulose and stir until it is completely dissolved. Cool down to 40-50℃ and add cashew phenol polyoxyethylene ether and phenylboronic acid. Adjust the pH to 4.0-5.0 with 0.06-0.10mol / L hydrochloric acid solution and stir at 200-300r / min for 2.5-4.0h. (2) Adjust the pH of the system obtained in step (1) to 8.5-9.5 with a sodium hydroxide solution with a mass fraction of 28%-32%, stir continuously at a speed of 350-450 r / min, add 1,4-butanediol diglycidyl ether dropwise at a speed of 2-4 mL / min, and continue stirring for 1-2 h after the addition is complete. After cooling to 25-30℃, add sorbitol and stir at a speed of 200-300 r / min for 10-12 min, then add acetone and stir at a speed of 300-400 r / min for 10-15 min, and let it stand to precipitate for 30-40 min. (3) Filter the system obtained in step (2) with a 250-300 mesh filter, wash the obtained solid with anhydrous ethanol 2-3 times, place the washed precipitate in a vacuum drying oven, dry it for 14-18 hours at 40-50℃ and vacuum degree -0.08MPa~-0.095MPa, pulverize it, and obtain borate ester dynamically cross-linked cellulose microgel with an average particle size of 500-700nm.

8. A method for preparing a naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Add 60%-75% of deionized water to the reaction vessel, heat to 40-50℃, stir continuously at 250-350r / min, add borate ester dynamic cross-linked cellulose microgel, keep warm and stir for 35-50min to obtain a uniformly dispersed gel suspension. S2. Keep the system obtained in step S1 at 40-50℃, and add rosin polyether modified naphthalene sulfonate condensate, sulfonated lignin, and polycarboxylate water-reducing agent in sequence, and stir at 300-400r / min for 60-80min. S3. Cool the system obtained in step S2 to 25-35℃, add isotridecyl alcohol polyoxyethylene ether, antifreeze and humectant, sodium gluconate, stir at 300-400 r / min for 35-50 min, add tris(hydroxymethyl)aminomethane-hydrochloric acid buffer pair, stir at 300-400 r / min for 15-25 min, and stabilize the pH of the system at 8.0-8.

5. S4. Add auxiliary stabilizer to the system obtained in step S3, stir at 100-180 r / min for 25-35 min, add the remaining deionized water and polyether modified polysiloxane, stir at 100-180 r / min for 20-30 min, then transfer the product to a curing tank, let it stand and cure at 25-30℃ for 14-18 h, filter, and obtain naphthalene sulfonate modified coal-water slurry dispersion stabilizer.

9. The method for preparing the naphthalene sulfonate-modified coal-water slurry dispersion stabilizer according to claim 8, characterized in that, In step S4, the filter used for filtration is a 200-300 mesh stainless steel filter.

10. The application of a naphthalene sulfonate-modified coal-water slurry dispersant and stabilizer as described in any one of claims 1-7 in the preparation of coal-water slurry, characterized in that, The amount of the coal-water slurry dispersant stabilizer used is 0.45%-0.55% of the dry coal mass.

Images