A method for preparing water coal slurry additive based on double waste raw materials, the additive and application thereof

Abstract

The present application belongs to the technical field of fine chemical industry and industrial solid waste resource utilization, and particularly relates to a method for preparing water coal slurry additive based on double hazardous waste raw materials, the additive and application thereof. The present application takes divinyl ketone distillation residue and disperse dye waste liquid as raw materials, excavates the additional value of active components in the two types of hazardous waste which can be deeply utilized, obtains new products through activation, acidification and catalytic reaction, realizes the effect of "dispersion-stability" cooperation, solves the pain points of traditional water coal slurry additive, such as "difficult to balance dispersion and stability, high synthesis cost", realizes the resource high-value utilization of double hazardous waste, reduces the environmental protection disposal pressure and high cost, reduces the dependence of additive preparation on special chemical raw materials, creates great economic benefits for enterprises, and has environmental protection benefits and resource value. The additive can make the water coal slurry have no precipitation and stratification for 60 days, the apparent viscosity is less than or equal to 1000 mPa·s, and the water coal slurry concentration is increased to 65% or above.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical industry and industrial solid waste resource utilization technology, specifically relating to a method for preparing coal-water slurry additives based on the synergistic preparation of two hazardous waste raw materials, the additives and their applications. Background Technology

[0002] Coal-water slurry is a coarsely dispersed solid-liquid system, thermodynamically unstable. Industrial applications require it to simultaneously possess high concentration, low viscosity, good flowability, and long-term storage stability. Additives, as the core and essential additives in coal-water slurry preparation, directly determine the slurry's slurry-forming properties, rheological characteristics, and stability, and are one of the key factors restricting the widespread adoption of coal-water slurry technology.

[0003] Currently, the main types of additives used in industrial coal-water slurry are naphthalene sulfonate formaldehyde condensate-based, lignin-based, humic acid-based, and polycarboxylate-based additives. Naphthalene sulfonate-based additives have excellent dispersibility, but poor coal slurry stability, are prone to hard precipitation, and industrial naphthalene is expensive. Lignin-based additives, while having abundant raw materials and low cost, generally have moderate slurry stability, but the slurry viscosity is high, impurity content is high, and performance fluctuates significantly. Polycarboxylate-based additives have moderate dispersibility, but the synthesis process is complex and the cost is high. The difficulty in simultaneously achieving both dispersibility and stability is a common pain point in the industry.

[0004] In recent years, scholars both domestically and internationally have explored the use of industrial waste to prepare coal-water slurry additives in search of lower-cost raw material sources for additives. For example, there has been extensive research on preparing lignin-based additives using papermaking black liquor as raw material. However, the composition of papermaking black liquor fluctuates greatly with the pulping process, resulting in unstable product performance, significant differences in composition between different manufacturers, and the need to add large amounts of sulfonating agents, sulfuric acid, and other chemical reagents. It is worth noting that single lignin-based additives cannot achieve efficient dispersibility and excellent stability. Some studies have attempted to use dyeing and printing wastewater to directly replace pulping water to prepare coal-water slurry without additives, but the highest slurry concentration reached was only about 60%, and the slurry performance still lagged behind that of conventional additive systems.

[0005] Diketene, an important fine chemical intermediate in the organic chemical industry, is mainly synthesized through the high-temperature cracking of acetic acid to produce ketene, which is then synthesized via dimerization. Due to the extremely unstable chemical properties of ketene and diketene, they are prone to self-polymerization during distillation recovery, generating distillation residues mainly composed of polymers and high polymers, accounting for 6%–8%, which are typical industrial hazardous wastes. Existing treatment technologies mainly fall into two categories: hydrolysis recovery can recover small amounts of acetone and acetic acid, but the recovery rate is low and equipment maintenance costs are high; direct incineration, while simple to operate, easily generates air pollution and has high tail gas purification costs, failing to achieve resource utilization of high-value-added components such as polymers in the residue. CN110981717A discloses a method for hydrolyzing diketene residue. The method involves mixing the residue with a post-pump liquid containing crude diketene and then feeding the mixture into a hydrolysis reactor to recover acetone and acetic acid. However, the analysis of the residue in this method is limited to the hydrolysis and recovery of residual diketene, without exploring the reactivity of polymers, polymers, and other byproducts containing unsaturated bonds. CN101314743A discloses an industrial coal additive, prepared by combining solid diketene residue with quicklime, potassium permanganate, etc. However, it only utilizes the calorific value and combustion expansion characteristics of the residue for energy recovery, resulting in low added value.

[0006] The production of disperse dyes also generates a large amount of industrial wastewater with high chroma, high COD, and poor degradation. This wastewater contains inorganic active substances such as sulfates and sulfites, as well as organic substances such as phenol and anthraquinone. Conventional treatment mainly involves hazardous waste incineration, which is costly. CN111825816A proposes using wastewater from the production of 1-aminoanthraquinone and DSD acid to prepare coal-water slurry additives. However, this patent actually relies mainly on wastewater to provide the aqueous medium, and still requires the addition of large amounts of chemical raw materials such as phenol, acetone, sulfonating agents, and formaldehyde as the main components of the synthesized water-reducing agent. The resource utilization rate of the wastewater itself is low.

[0007] In summary, existing technologies have two shortcomings: First, the separate treatment of diketene distillation residue and disperse dye wastewater results in high treatment costs and fails to fully exploit their active components for high-value resource utilization. Second, existing coal-water slurry additives are complex formulations of various chemical materials, making it difficult to balance dispersibility and stability, and they have poor compatibility with complex coal types such as low-rank coal. If the organic components rich in active groups in these two types of hazardous waste can be chemically modified and utilized in a targeted manner to synergistically prepare high-performance coal-water slurry additives, it is hoped that both the hazardous waste disposal problem and the additive performance bottleneck can be solved simultaneously, achieving a balance between environmental protection and economic benefits. Summary of the Invention

[0008] The technical problem to be solved by this invention is to provide a method for preparing coal-water slurry additives based on the synergistic reaction of two hazardous waste raw materials, the additives and their applications. Through the synergistic chemical reaction of the two hazardous wastes, the directional structural design and functional regulation at the molecular level are achieved, and the additives are transformed into highly adaptable and high-value-added high-efficiency additives, while meeting the requirements of environmental compliance and low cost, and adapting to different coal qualities and types.

[0009] The technical solution adopted is as follows: A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reaction vessel, add industrial acid to control the pH value to be acidic, then add the catalyst, stir and heat to carry out the activation reaction; (2) Continue to add disperse dye waste liquid into the reactor, keep stirring and continue heating to carry out the reaction; (3) After the reaction is complete, cool the mixture to room temperature and adjust the pH of the mixture to neutral to weakly alkaline. (4) Filter out unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. Prepare liquid additives or solid powder additives by spray drying technology as needed.

[0010] Preferably, the industrial acid in step (1) is one or more of hydrochloric acid, sulfuric acid, and acetic acid of various concentrations, and after being added, the pH value of the mixture is controlled within the range of 3 to 5; the concentration of the industrial acid is 5% to 30%, and it is diluted with deionized water to 5% to 10% before use.

[0011] Preferably, the catalyst in step (1) is one or more of ferrous sulfate, ferrous chloride, cuprous iodide, copper nitrate, manganese dioxide, and manganese acetate, and the amount used is 0.5% to 2% of the diketene distillation residue.

[0012] Preferably, in step (1), the stirring speed is 200-380 rpm, the temperature is increased to 40-60℃ at 1-5℃ / min, and the reaction is kept at this temperature for 2-6 hours.

[0013] Preferably, the solid content of the disperse dye wastewater in step (2) is 5% to 30%, and the mass percentage of diketene distillation residue to disperse dye wastewater (i.e., the dry weight percentage of solids in the two materials) is 0.2 to 0.8:1.

[0014] Preferably, in step (2), after adding disperse dye wastewater, the mixture is heated to a temperature of 100-140 °C, a pressure of 0.25 MPa-0.35 MPa, and a reaction time of 6-12 hours.

[0015] Preferably, in step (3), the cooling method is natural cooling; The pH of the mixture is adjusted using an alkali, which is one or more of sodium hydroxide or potassium hydroxide in solid or liquid form. After adding the alkali, the pH of the mixture is controlled to be ≥6.5.

[0016] Preferably, in step (4), the unreacted residue / insoluble matter after filtration is ≤3%.

[0017] The present invention also provides a coal-water slurry additive, which is prepared by a method based on the synergistic preparation of coal-water slurry additives from two hazardous waste raw materials, and the solid content of the additive is 10-40%.

[0018] When the additive described in this invention is used in coal-water slurry, it is mixed according to the following dosage: coal 65%-70% by mass, water 30%-35%, and the additive accounting for 2.5-4‰ of the total coal-water slurry mass. The mixture is then fed into a ball mill and ground to 200 mesh with a passing rate of ≥80%. After passing the test, it is fed into a coal-water slurry boiler for combustion.

[0019] This invention grafts and modifies various anthraquinone disperse dye molecules containing amino, nitro, and carboxyl groups, as well as phenol molecules, with diketene reactive polymers to form a dual-effect coal-water slurry additive that balances dispersibility and stability. Diketene distillation residue contains a large number of active components, which, through detailed analysis, have been identified as including diketene, diketene polymers, diketene high polymers, acetic acid, acetic anhydride, methyl acetate, dehydroacetic acid, methyl acetoacetate, 2-hydroxyethyl acetate, 2,6-dimethyl-3-acetyl-4-pyranone, 2,2-dimethoxypropane, cyclopropylmethyl ketone, 2,6-dimethyl-4-pyranone, 2,2-dimethylpropane, methyl 3,5-diketohexanoate, and cyclopropylmethyl ketone, among other compounds. These compounds, after activation, become... It has high reactivity and can react with amino, nitro, and carboxyl groups in disperse dye waste liquid (printing and dyeing hazardous waste, containing dispersants, sulfates, sulfites and various amphiphilic dye molecules with hydroxyl, amino and nitro groups) to form a macromolecular additive that takes into account both hydrophilic and hydrophobic end groups. This meets the requirements for the hydrophilicity and lipophilicity of additives when mixing water and coal, so as to improve the dispersion effect of coal-water slurry to form a fluid with excellent viscosity, and also have good stability, without stratification or even precipitation and agglomeration during standing or long-distance transportation.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention uses diketene distillation residue and disperse dye waste liquid as composite raw materials. Through an integrated process of "directional pretreatment - precise synergistic reaction - functional post-treatment - water-coal slurry adaptation application", it utilizes the complementarity of active ingredients in the two types of hazardous waste to achieve the preparation of water-coal slurry dispersant with "dispersion-stability" synergistic function. At the same time, a dedicated automated production system is provided to ensure the implementation of the process. This fundamentally solves the industry pain points of traditional water-coal slurry additives, such as "difficulty in balancing dispersibility and stability, high cost of chemical synthesis, and mixed sources of low-grade raw materials with large batch-to-batch composition differences". It realizes the high-value utilization of the two types of hazardous waste, which not only reduces the pressure and high cost of environmental disposal, "turns waste into treasure", but also reduces the dependence of additive preparation on special chemical raw materials, creating great economic benefits for enterprises and combining environmental benefits and resource value.

[0021] (2) The dispersibility and stability of the coal-water slurry additive prepared by this invention meet the standards simultaneously. Because the hydroxyl and amino (hydrophilic) groups in the dye waste liquid are grafted with the unsaturated bonds, carboxyl groups, carbonyl groups, and free radicals generated by activation in the residue polymers, polymers, pyranones, dehydroacetic acid, etc., through condensation or free radical polymerization reactions to form structurally matched amphiphilic molecules, which can reduce the surface tension of coal-water slurry through hydrophilic groups and have a steric hindrance effect (dispersion effect) through the polymer structure, and can also anchor the lipophilic end of the amphiphilic group to the surface of coal particles and bind water molecules through the hydrophilic end to form a stable protective film (stabilization effect), thus solving the core contradiction in the industry.

[0022] (3) The water-coal slurry additive product prepared by this invention has good performance stability. The activated diketene waste liquid has a large number of different active sites, and the disperse dye waste liquid also contains components with different active groups. Under the developed process conditions, a variety of amphiphilic additive components can be generated, which can effectively combine with coal molecules and achieve the dispersion effect between coal molecules through steric hindrance or electrostatic repulsion. In addition, this molecular type has good stability, and the multi-site effect can greatly improve the interaction force between macromolecules or high molecular weight substances and water and coal. The amphiphilic anchor points interact with water and coal respectively, ensuring that water and coal do not separate, thus achieving long-term stability of water-coal slurry without the need to add expensive stabilizers with thickening effect. The added stabilizers will consume the effect of the dispersant and increase the apparent viscosity of water-coal slurry. The product of this invention can prevent sedimentation and water separation stratification in coal-water slurry for 60 days and prevent hard sedimentation for 70 days. The apparent viscosity of the coal-water slurry is ≤1000 mPa·s, which meets the actual needs of industry (the apparent viscosity of coal-water slurry in actual applications is generally between 700 and 1000 mPa·s). Furthermore, the apparent viscosity of the coal-water slurry can be adjusted by changing the amount of additives according to the needs of industrial equipment, and the concentration of coal-water slurry can be increased to 65% or more.

[0023] (4) This invention realizes the comprehensive utilization of diketene distillation residue and disperse dye waste liquid. It uses low-cost hazardous waste as the core raw material, and the process reaction is easy to adjust. The catalyst is simple and readily available. It does not require complex equipment and high-energy-consuming steps, so the preparation cost is greatly reduced and the industrial application potential is outstanding.

[0024] (5) This invention not only realizes the resource utilization of hazardous waste, but also demonstrates significant economic benefits in application. Experiments show that, under the conditions of achieving the same pulp concentration (≥65%) and rheological properties (apparent viscosity ≤1000 mPa·s), the appropriate addition amount of the additive of this invention is 2.5 to 4‰ of the total coal-water slurry mass, which is much lower than the 8 to 10‰ generally required by similar commercial products, significantly reducing the user's usage cost, while avoiding the potential negative impact on the stability of the slurry due to the introduction of additional inorganic salts by excessive addition. Attached Figure Description

[0025] Figure 1 This is a flowchart of the preparation method of the present invention.

[0026] Figure 2 This is a comparison chart showing the results of the water-coal slurry preparation performance tests of Examples 1-6 and Comparative Examples 1-3. Detailed Implementation

[0027] The accompanying drawings are for illustrative purposes only; it should be understood that these embodiments are for illustrating the invention only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless specific conditions are specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight.

[0028] The apparent viscosity of the coal-water slurry was tested using a coal-water slurry viscometer SPT-NXS-4C manufactured by Chengdu Instrument Factory.

[0029] Unless otherwise specified, the raw materials and chemical reagents used in this invention can all be obtained through legitimate commercial channels, and the standards for chemical reagents are those commonly used in laboratories.

[0030] Example 1 like Figure 1 As shown, a method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reaction vessel, turn on the mechanical stirrer at 300 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, slowly raise the temperature (3 ℃ / min) to 60 ℃, and keep the activation reaction at the temperature for 3 hours; wherein, the industrial acid is hydrochloric acid with a concentration of 5%, and after adding it, the pH value of the mixture is controlled at about 4.

[0031] The catalyst is ferrous sulfate, and the amount used is 1.5% of the diketene distillation residue.

[0032] (2) Continue to add disperse dye waste liquid into the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste water is 20%; the mass percentage of diketene distillation residue to disperse dye waste liquid (i.e., the dry weight percentage of solids in the two materials) is 0.6:1.

[0033] After adding disperse dye wastewater, the reaction system was heated to a temperature of 130 °C and a pressure of 0.25 MPa for 8 hours.

[0034] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use an alkali to adjust the pH of the mixture. The alkali is sodium hydroxide liquid with a concentration of 30%. After adding caustic soda, control the pH of the mixture to 7.0.

[0035] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 1.5%.

[0036] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0037] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 23%. When used in coal-water slurry, it is mixed according to the following dosage: coal 65%, water 35%, and the additive accounting for 2.5‰ of the total mass of coal-water slurry. The mixture is then fed to a ball mill and ground to 200 mesh with a passing rate of 85%. The apparent viscosity of the coal-water slurry is 868 mPa·s. There is no sedimentation after 60 days, and the sedimentation amount (soft sediment, which can be recovered after stirring) after 70 days is only 2.7%. After passing the test, it is fed into a coal-water slurry boiler for combustion.

[0038] Example 2 A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 250 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, slowly raise the temperature (2 ℃ / min) to 50 ℃, and maintain the temperature for 6 hours to activate the reaction; wherein, the industrial acid is sulfuric acid with a concentration of 98%, diluted to 10% before use, and the pH value of the mixture is controlled at about 4 after addition. The catalyst is ferrous chloride, and the amount used is 1.5% of the diketene distillation residue.

[0039] (2) Continue to add disperse dye waste liquid into the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste water is 15%; the mass percentage of diketene distillation residue to disperse dye waste liquid (i.e., the dry weight percentage of solids in the two materials) is 0.5:1.

[0040] After adding disperse dye wastewater, the reaction system was heated to 120 °C and 0.25 MPa for 8 hours.

[0041] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use a base to adjust the pH of the mixture. The base is solid sodium hydroxide. After adding the base, control the pH of the mixture to 7.0.

[0042] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 2.6%.

[0043] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0044] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 18%. When used in coal-water slurry, it is mixed according to the following dosage: coal 65%, water 35%, and the additive accounting for 3.5‰ of the total mass of coal-water slurry. The mixture is then fed to a ball mill and ground to 200 mesh with a passing rate of 83%. The apparent viscosity of the coal-water slurry is 811 mPa·s. There is no sedimentation after 60 days, and the sedimentation amount after 70 days is only 2.9%. After passing the test, it is fed into a coal-water slurry boiler for combustion.

[0045] Example 3 A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 360 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, and slowly raise the temperature (5 ℃ / min) to 60 ℃, and maintain the temperature for 6 hours to activate the reaction; wherein, the industrial acid is hydrochloric acid with a concentration of 15%, and the pH value of the mixture is controlled at about 4 after addition. The catalyst is ferrous sulfate, and the amount used is 2% of the diketene distillation residue.

[0046] (2) Continue to add disperse dye waste liquid to the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste liquid is 25%; the mass percentage of diketene distillation residue to disperse dye waste liquid (i.e., the dry weight percentage of solids in the two materials) is 0.8:1. After adding disperse dye waste liquid, continue heating the reaction system to a temperature of 140 ℃, a pressure of 0.30 MPa, and a reaction time of 10 hours.

[0047] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use an alkali to adjust the pH of the mixture. The alkali is sodium hydroxide liquid with a concentration of 20%. After adding caustic soda, control the pH of the mixture to 6.8.

[0048] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 2%.

[0049] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0050] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 28%. When used in coal-water slurry, it is mixed according to the following dosage: coal 68%, water 32%, and the additive accounting for 2.5‰ of the total mass of coal-water slurry. After mixing, it is fed to a ball mill and ground to 200 mesh with a passing rate of 88%. The apparent viscosity of the coal-water slurry is 848 mPa·s. There is no sedimentation after 60 days, and the sedimentation amount after 70 days is only 3.5%. After passing the test, it is fed to a coal-water slurry boiler for combustion.

[0051] Example 4 A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 280 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, and slowly raise the temperature (3 ℃ / min) to 50 ℃, and maintain the temperature for 4 hours to activate the reaction; wherein, the industrial acid is hydrochloric acid with a concentration of 5%, and the pH value of the mixture is controlled at about 4 after addition. The catalyst is cuprous iodide, and the amount used is 0.5% of the diketene distillation residue.

[0052] (2) Continue to add disperse dye waste liquid to the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste liquid is 10%; the mass percentage of diketene distillation residue to disperse dye waste liquid (i.e., the dry weight percentage of solids in the two materials) is 0.5:1. After adding disperse dye waste liquid, continue heating the reaction system to a temperature of 120 °C, a pressure of 0.25 MPa, and a reaction time of 6 hours.

[0053] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use a base to adjust the pH of the mixture. The base is solid potassium hydroxide. After adding the base, control the pH of the mixture to 7.3.

[0054] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 2.4%.

[0055] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0056] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 13%. When used in coal-water slurry, it is mixed according to the following dosage: coal 65%, water 35%, and the additive accounting for 4‰ of the total mass of coal-water slurry. After mixing, it is fed to a ball mill and ground to 200 mesh with a passing rate of 84%. The apparent viscosity of the coal-water slurry is 752 mPa·s. There is no sedimentation after 60 days, and the sedimentation amount after 70 days is only 1.8%. After passing the test, it is fed to a coal-water slurry boiler for combustion.

[0057] Example 5 A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 330 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, slowly raise the temperature (3 ℃ / min) to 50 ℃, and maintain the temperature for 5 hours to activate the reaction; wherein, the industrial acid is acetic acid with a concentration of 10%, and the pH value of the mixture is controlled at about 4 after addition. The catalyst is cuprous iodide, and the amount used is 1% of the diketene distillation residue.

[0058] (2) Continue to add disperse dye waste liquid to the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste liquid is 20%; the mass percentage of diketene distillation residue to disperse dye waste liquid (i.e., the dry weight percentage of solids in the two materials) is 0.6:1. After adding disperse dye waste liquid, continue heating the reaction system to a temperature of 130 °C, a pressure of 0.25 MPa, and a reaction time of 8 hours.

[0059] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use an alkali to adjust the pH of the mixture. The alkali is liquid sodium hydroxide with a concentration of 20%. After adding the alkali, control the pH of the mixture to 7.0.

[0060] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 1.8%.

[0061] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0062] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 20%. When used in coal-water slurry, it is mixed according to the following dosage: coal 65%, water 35%, and the additive accounting for 3.0‰ of the total coal-water slurry mass. After mixing, it is fed to a ball mill and ground to 200 mesh with a passing rate of 82%. The apparent viscosity of the coal-water slurry is 836 mPa·s. There is no sedimentation after 60 days, and the sedimentation amount after 70 days is only 3.2%. After passing the test, it is transported to a coal-water slurry boiler for combustion.

[0063] Example 6 A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 380 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, and slowly raise the temperature (3 ℃ / min) to 60 ℃, and maintain the temperature for 6 hours to activate the reaction; wherein, the industrial acid is hydrochloric acid with a concentration of 20%, and the pH value of the mixture is controlled at about 4 after addition. The catalyst is cuprous nitrate, and the amount used is 1.5% of the diketene distillation residue.

[0064] (2) Continue to add disperse dye waste liquid to the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste liquid is 25%; the mass percentage of diketene distillation residue to disperse dye waste liquid (i.e., the dry weight percentage of solids in the two materials) is 0.8:1. After adding disperse dye waste liquid, continue heating the reaction system to a temperature of 140 °C, a pressure of 0.32 MPa, and a reaction time of 12 hours.

[0065] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use an alkali to adjust the pH of the mixture. The alkali is liquid sodium hydroxide with a concentration of 30%. After adding the alkali, control the pH of the mixture to 7.3.

[0066] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 2.5%.

[0067] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0068] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 27%. When used in coal-water slurry, it is mixed according to the following dosage: coal 66%, water 34%, and the additive accounting for 3.5‰ of the total coal-water slurry mass. After mixing, it is fed to a ball mill and ground to 200 mesh with a passing rate of 82%. The apparent viscosity of the coal-water slurry is 818 mPa·s. There is no sedimentation after 60 days, and the sedimentation amount after 70 days is only 3.5%. After passing the test, it is fed into a coal-water slurry boiler for combustion.

[0069] The parameters and indicators of the preparation methods described in Examples 1-6 of this invention are summarized in Table 1.

[0070] Table 1. Comparison of Process Parameters and Indicators for Examples Comparative Example 1 A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 300 rpm, add industrial acid to control the pH value to be acidic, then add the catalyst, slowly raise the temperature to 30 ℃, and maintain the temperature for 3 hours to activate the reaction; wherein, the industrial acid is hydrochloric acid with a concentration of 5%, and the pH value of the mixture is controlled at about 4 after addition. The catalyst is iron oxide, and the amount used is 1% of the diketene distillation residue.

[0071] (2) Continue to add disperse dye waste liquid to the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste water is 30%; the solid content percentage of diketene distillation residue to disperse dye waste liquid is 0.3:1. After adding disperse dye waste water, continue heating the reaction system to a temperature of 120 ℃, a pressure of 0.25 MPa, and a reaction time of 8 hours.

[0072] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use an alkali to adjust the pH of the mixture. The alkali is sodium hydroxide liquid with a concentration of 30%. After adding caustic soda, control the pH of the mixture to 7.5.

[0073] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residues / insoluble matter after filtration is 18.1%.

[0074] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0075] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 7%. When used in coal-water slurry, it is mixed according to the following dosage: coal 65%, water 35%, and the additive accounting for 6‰ of the total coal-water slurry mass. The mixture is then fed to a ball mill and ground to 200 mesh with a passing rate of 80%. The apparent viscosity of the coal-water slurry is 980 mPa·s. Sedimentation begins to appear after 30 days, with a sedimentation amount of 52.8% after 60 days (developing into hard sedimentation, which is irreversible), 80.2% after 70 days, and 100% after 80 days. The additive has a low yield, requires a large amount, and produces coal-water slurry with poor stability.

[0076] Comparative Example 2 like Figure 1 As shown, a method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials includes the following steps: (1) Add the diketene distillation residue to the reactor, turn on the mechanical stirrer at 380 rpm, add industrial acid to control the pH value to be acidic, and then add the catalyst; wherein, the industrial acid is hydrochloric acid with a concentration of 5%, and after adding it, the pH value of the mixture is controlled at about 4. The catalyst is cuprous iodide, and the amount used is 0.2% of the diketene distillation residue.

[0077] (2) Continue to add disperse dye waste liquid to the reactor, keep stirring and continue heating to carry out the reaction; wherein, the solid content of the disperse dye waste water is 20%; the solid content percentage of diketene distillation residue to disperse dye waste liquid is 1:1. After adding disperse dye waste water, continue heating the reaction system to a temperature of 120 ℃, a pressure of 0.25 MPa, and a reaction time of 8 hours.

[0078] (3) After the reaction is complete, allow the mixture to cool naturally to room temperature and adjust the pH of the mixture to neutral. The adjustment method is as follows: use an alkali to adjust the pH of the mixture. The alkali is sodium hydroxide liquid with a concentration of 30%. After adding caustic soda, control the pH of the mixture to 8.0.

[0079] (4) Filter to remove unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. The mass ratio of unreacted residue / insoluble matter after filtration is 22.8%.

[0080] Liquid additives can be prepared as needed, or solid powder additives can be prepared using spray drying technology.

[0081] The additive prepared by the method of co-preparing coal-water slurry additive based on two hazardous waste raw materials described in this invention has a solid content of 5%. When used in coal-water slurry, it is mixed according to the following dosage: coal 65%, water 35%, and the additive accounting for 10‰ of the total coal-water slurry mass. The mixture is then fed into a ball mill and ground to 200 mesh, with a passing rate of 82%. The apparent viscosity of the coal-water slurry is 1721 mPa·s. Sedimentation begins to appear after 30 days, with a sedimentation amount of 38.5% after 60 days, 61.1% after 70 days, and 100% after 80 days. While the apparent viscosity of the coal-water slurry prepared with the additive is very high, it still cannot guarantee satisfactory stability. Furthermore, the additive has a low yield, requires a large dosage, and the high apparent viscosity of the prepared coal-water slurry makes it unsuitable for production use.

[0082] Comparative Example 3 The product uses commercially available industrial-grade naphthalene sulfonate formaldehyde condensate water-coal slurry additive (a mainstream commercial product in the domestic water-coal slurry field). The product is a brown powder with a solid content of 98%.

[0083] When used in coal-water slurry, the mixture is prepared with 65% coal, 35% water, and the additive accounting for 8‰ of the total slurry. The mixture is then fed into a ball mill and ground to 200 mesh, achieving a throughput of 85%. The apparent viscosity of the coal-water slurry is 951 mPa·s. Sedimentation begins to appear after 30 days, with 48.8% sedimentation at 60 days, 57.6% at 70 days, and 92.1% at 80 days. To increase sales, the manufacturer uses a higher amount of additive than intended. Furthermore, the coal-water slurry has poor stability. The manufacturer states that additional stabilizer is needed, which would increase product costs and potentially raise the overall additive usage to over 9‰.

[0084] The process parameters of Comparative Examples 1-3 are summarized, and the results are shown in Table 2.

[0085] Table 2 Comparison of process parameters and indicators for comparative examples Examples 1-6 and Comparative Examples 1-3 above investigated the effects of parameters such as raw material ratio, catalyst type and dosage, and activation process on the additive preparation process. To objectively evaluate the application performance of each sample of coal-water slurry, this invention conducted unified tests using the same coal quality and the same slurry preparation conditions, focusing on core indicators such as additive dosage, apparent viscosity of coal-water slurry, and storage stability.

[0086] The process parameters and performance of Examples 1-6 and Comparative Examples 1-3 are summarized. The apparent viscosity of the coal-water slurry was determined according to GB / T 18856.4-2008 "Coal-water slurry test methods - Part 4: Determination of apparent viscosity"; the stability of the coal-water slurry was tested according to GB / T 18856.5-2008 "Coal-water slurry test methods - Part 5: Determination of stability". The test results are summarized in Table 3.

[0087] Table 3 Comparison of the results of the water-coal slurry preparation performance test between Examples 1-6 and Comparative Examples 1-3 As shown in Table 3 and Figure 2 As shown, the coal-water slurry prepared in Examples 1-6 exhibits significantly better stability than that in Comparative Examples 1-3, and its apparent viscosity is lower than that in Comparative Examples 1-3, better meeting the actual needs of production applications. When the mass percentage ratio of diketene distillation residue to disperse dye waste liquid is too high (exceeding 0.8:1), or the activation temperature is too low, or the catalyst is used improperly, or there is no activation reaction, the properties of the prepared additive-based coal-water slurry are poor, or the stability is extremely poor when trying to obtain a suitable apparent viscosity to achieve good fluidity.

[0088] Comparative experiments were conducted on Examples 1-6 of the present invention and Comparative Examples 1-3 under the same pulping conditions. The results showed that the additive dosage of Examples 1-6 of the present invention was only 2.5-4‰ of the total coal-water slurry mass, which was sufficient to stably increase the coal-water slurry concentration to over 65%, and the viscosity of the coal-water slurry was controlled below 1000 mPa·s. After standing for 60 days, no sedimentation or stratification occurred, demonstrating excellent dispersion and long-term storage stability. In contrast, even when the dosage of Comparative Examples 1-3 was significantly increased to 6‰-10‰ (nearly twice the dosage of the present invention), the viscosity of the prepared coal-water slurry remained high, the concentration could not be further increased, and the slurry showed obvious water separation and hard sedimentation after a short period of standing, indicating significantly inferior stability compared to the present invention. Therefore, it can be seen that the present invention achieves a dispersion and stabilization effect far exceeding that of the comparative ratio with an addition amount far lower than that of the prior art, which fully demonstrates that the new additive synthesized by utilizing active components has a stronger adsorption and anchoring ability and a better steric hindrance effect on both coal particles and water. While significantly reducing the user's operating costs, it ensures the actual working conditions of long-term stable storage and transportation, continuous production operation, start-up and shutdown of coal-water slurry products.

[0089] Example 7 The difference from Example 1 is that the amount of catalyst (ferrous sulfate) used in the active reaction was increased to 2%, the reaction temperature was raised to 140 °C after adding diketene distillation residue, and the pressure was 0.35 MPa. Other parameters remained the same as in Example 1. The mass ratio of unreacted residue / insoluble matter after filtration was <1%.

[0090] The additive prepared in this invention, when applied to coal-water slurry, can increase the solid content of the slurry to 68%. When mixed with 32% coal water and the additive at a mass ratio of 2.5‰ of the total coal-water slurry, the mixture is ground to 200 mesh using a ball mill, achieving a passing rate of 85%. The apparent viscosity of the coal-water slurry is 837 mPa·s, exhibiting excellent fluidity. No sedimentation occurs after 60 days, and less than 1% soft sediment appears after 70 days. The additive prepared in this invention has excellent universality for coal from different regions and of different qualities both domestically and internationally. High-solid-content, fluid, and stable coal-water slurry products can be obtained by adjusting the apparent viscosity parameter, meeting the needs of various special operating conditions such as production, storage, transportation, operation, and start-up / shutdown, while also helping enterprises reduce costs and increase efficiency.

[0091] Example 8 The difference from Example 1 is that the additive prepared in this invention, when used in coal-water slurry, is mixed at a ratio of 65% coal, 35% water, and 4‰ of the total coal-water slurry mass. After mixing, it is ground to 200 mesh using a ball mill, achieving a throughput of 84%. The apparent viscosity of the coal-water slurry is 583 mPa·s, exhibiting excellent water-like fluidity while maintaining excellent static stability, such as no sedimentation after 60 days and less than 5% sedimentation after 70 days. When the additive prepared in this invention is used in coal-water slurry production, even if the apparent viscosity of the slurry is low due to excessive additive input or high ash content in the purchased coal, it still achieves extremely high stability, ensuring the needs of storage, transportation, production, and start-up / shutdown operations. The raw material used in this invention is production waste liquid, which saves on hazardous waste disposal costs. Furthermore, the additive product obtained can significantly reduce the amount needed, resulting in a substantial cost reduction compared to the 8-10‰ of existing technologies.

[0092] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials, characterized in that, Includes the following steps: (1) Add the diketene distillation residue to the reaction vessel, add industrial acid to control the pH value to be acidic, then add the catalyst, stir and heat to carry out the activation reaction; (2) Continue to add disperse dye waste liquid into the reactor, keep stirring and continue heating to carry out the reaction; (3) After the reaction is complete, cool the mixture to room temperature and adjust the pH of the mixture to neutral to weakly alkaline. (4) Filter out unreacted impurities and residues to obtain a dual-effect coal-water slurry additive that balances dispersibility and stability. Prepare liquid additives or solid powder additives by spray drying technology as needed.

2. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, The industrial acid mentioned in step (1) is one or more of hydrochloric acid, sulfuric acid, and acetic acid of various concentrations. After being added, the pH value of the mixture is controlled within the range of 3 to 5. The concentration of the industrial acid is 5% to 30%, and it is diluted with deionized water to 5% to 10% before use.

3. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, The catalyst mentioned in step (1) is one or more of ferrous sulfate, ferrous chloride, cuprous iodide, copper nitrate, manganese dioxide, and manganese acetate, and the amount used is 0.5% to 2% of the diketene distillation residue.

4. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, In step (1), the stirring speed is 200-380 rpm, the temperature is increased to 40-60℃ at 1-5℃ / min, and the reaction is kept at this temperature for 2-6 hours.

5. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, The solid content of the disperse dye wastewater in step (2) is 5% to 30%, and the mass percentage of diketene residue to disperse dye wastewater is 0.2 to 0.8:

1.

6. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, After adding disperse dye wastewater in step (2), continue heating to a temperature of 100-140 °C, a pressure of 0.25 MPa-0.35 MPa, and a reaction time of 6-12 hours.

7. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, In step (3), the cooling method is natural cooling; the pH value of the mixture is adjusted by using an alkali, which is one or more of sodium hydroxide or potassium hydroxide in solid or liquid form. After adding the alkali, the pH of the mixture is controlled to be ≥6.

5.

8. The method for preparing coal-water slurry additives based on the synergistic use of two hazardous waste raw materials according to claim 1, characterized in that, In step (4), the unreacted residue / insoluble matter after filtration is ≤3%.

9. The additive prepared by the method for synergistic preparation of coal-water slurry additives based on dual hazardous waste raw materials as described in any one of claims 1-8, characterized in that, The solid content of the additive is 10-40%.

10. The application of the additive as described in claim 9 in coal-water slurry, characterized in that, The mixture is prepared by mixing coal (65%-70% by mass), water (30%-35% by mass), and the additives (2.5-4‰ by mass of the total coal-water slurry). The mixture is then fed into a ball mill and ground to 200 mesh with a passing rate of ≥80%. Once qualified, the mixture is fed into a coal-water slurry boiler for combustion.

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