Efficient coal water slurry additive and preparation method thereof

Abstract

The invention relates to the field of coal water slurry, in particular to an efficient coal water slurry additive and a preparation method thereof. The efficient coal water slurry additive comprises the following raw materials in percentage by mass: 20-40% of an auxiliary dispersant, 10-20% of a stabilizer, 5-10% of an interface agent, 1-5% of a combustion improver and the balance of a modified matrix agent. The finally prepared coal water slurry additive not only has the advantages of excellent dispersion effect, good stability and the like, but also can meet the requirements of stability, fluidity, combustion performance and the like of a coal water slurry system at the same time, so that the storage and use quality of the coal water slurry system is greatly improved, and the coal water slurry additive has very wide application potential.

Description

Technical Field

[0001] The present application relates to the field of water coal slurries, and more specifically, to a high - efficiency water coal slurry additive and its preparation method. Background Art

[0002] As a clean and efficient coal - based fuel, water coal slurry has been widely used in fields such as industrial boilers and power station boilers due to its high combustion efficiency, low pollution emissions, etc. Water coal slurry is composed of pulverized coal, water, and a small amount of additives, and is a fluid fuel that can be pumped, stored, and burned. It can not only improve the utilization efficiency of coal but also reduce pollutant emissions during coal combustion, which is of great significance for environmental protection.

[0003] However, the performance of water coal slurry, such as key indicators like stability, fluidity, and combustion performance, is affected by various factors. Among them, the selection and performance of additives are crucial. An ideal additive can not only enhance the dispersibility of water coal slurry, improve its fluidity, but also enhance the stability of water coal slurry, ensuring that it is not prone to layering or sedimentation during transportation and storage, and can promote complete combustion during combustion, further reducing pollutant emissions.

[0004] Traditional water coal slurry additives mostly use single components, such as lignosulfonates, naphthalene - based dispersants, etc. Although these additives can improve certain properties of water coal slurry to a certain extent, they generally have some problems. For example, the dispersion effect is limited, and single - component additives often have difficulty meeting the requirements of enhancing dispersibility, stability, and optimizing combustion performance simultaneously; the stability is poor. Due to the lack of comprehensive performance, the water coal slurry prepared with traditional additives is prone to layering after long - term storage, reducing the use efficiency. Summary of the Invention

[0005] Therefore, in order to effectively solve the above - mentioned existing problems, the present application provides a high - efficiency water coal slurry additive and its preparation method. The finally prepared water coal slurry additive of the present application not only has excellent dispersion effects and good stability, etc., but also can simultaneously meet the requirements of the stability, fluidity, and combustion performance of the water coal slurry system, thereby greatly improving the storage and use quality of the water coal slurry system and having very broad application potential.

[0006] The high - efficiency water coal slurry additive, in terms of mass percentage, the raw materials include: auxiliary dispersant 20 - 40%, stabilizer 10 - 20%, interfacial agent 5 - 10%, combustion aid 1 - 5%, and the modified matrix agent makes up the balance.

[0007] As a preferred embodiment, the mass ratio of the modified matrix agent, auxiliary dispersant, and stabilizer is (35 - 45):(25 - 35):(12 - 18).

[0008] As a preferred embodiment, the mass ratio of the modified matrix agent, the auxiliary dispersant and the stabilizer is (40 - 45):(28 - 32):(13 - 15).

[0009] As a preferred embodiment, the auxiliary dispersant is an acrylic acid - acrylamide copolymer.

[0010] As a preferred embodiment, the acrylic acid - acrylamide copolymer is an acrylic acid - 2 - acrylamido - 2 - methylpropanesulfonic acid copolymer.

[0011] As a preferred embodiment, the stabilizer is at least one of sodium chloride, calcium chloride, sodium sulfate and calcium sulfate.

[0012] As a preferred embodiment, the stabilizer is a composition of sodium chloride and calcium chloride or sodium sulfate.

[0013] As a preferred embodiment, the mass ratio of the sodium chloride to the calcium chloride / sodium sulfate is (3 - 4):(0.8 - 1.4).

[0014] As a preferred embodiment, the mass ratio of the sodium chloride to the calcium chloride / sodium sulfate is (3 - 3.5):(1 - 1.2).

[0015] As a preferred embodiment, the interfacial agent is a composition of sodium dodecylbenzenesulfonate and cetostearyl alcohol polyoxyethylene ether.

[0016] As a preferred embodiment, the mass ratio of the sodium dodecylbenzenesulfonate to the cetostearyl alcohol polyoxyethylene ether is (6 - 8):(1 - 1.5).

[0017] As a preferred embodiment, the mass ratio of the sodium dodecylbenzenesulfonate to the cetostearyl alcohol polyoxyethylene ether is (6.5 - 7):(1.2 - 1.4).

[0018] As a preferred embodiment, the combustion aid is at least one of potassium nitrate, sodium nitrate, potassium permanganate, barium nitrate and hydrogen peroxide.

[0019] As a preferred embodiment, the combustion aid is at least one of potassium nitrate, sodium nitrate and potassium permanganate.

[0020] As a preferred embodiment, the combustion aid is potassium nitrate.

[0021] As a preferred embodiment, the modified matrix agent is a modified lignosulfonate.

[0022] As a preferred embodiment, the preparation method of the modified lignosulfonate specifically includes the following steps: S1: Crush the alkali lignin, add hydrochloric acid solution and stir to remove residual lignosulfonate and ash, wash with water to neutral after centrifugation, and then mix with ethanol, ultrasonically disperse and vacuum dry to obtain activated lignin; S2: Add the activated lignin, aminosulfonic acid and EDTA to a high-pressure reactor, then add a mixed solvent of ethanol and water, heat up and keep the temperature for reaction, then add allyl glycidyl ether and glycidyl methacrylate and ammonium persulfate, heat up and keep the temperature for reaction; S3: After the reaction is completed, cool the reaction system, slowly add acetone, centrifuge and collect the precipitate after standing and separating layers, and then wash with a mixed solvent of ethanol and water and spray dry at high temperature to obtain the product.

[0023] As a preferred embodiment, the preparation method of the modified lignosulfonate specifically includes the following steps: S1: Crush the alkali lignin to 120-200 mesh, stir with 5-8% hydrochloric acid solution at 60-65°C for 2-3 h to remove residual lignosulfonate and ash, wash with water to neutral after centrifugation, and then mix with ethanol at a mass ratio of 1:(3-4), ultrasonically disperse and vacuum dry to obtain activated lignin; S2: Add the activated lignin, aminosulfonic acid and EDTA to a high-pressure reactor, then add a mixed solvent of ethanol and water, displace with nitrogen 3 times until the oxygen content < 50 ppm, heat up to 80-85°C and add dilute sulfuric acid dropwise to maintain the pH at 2.5-3.0, keep the temperature for reaction for 2-3 h, add allyl glycidyl ether and glycidyl methacrylate, and add ammonium persulfate evenly in two portions at intervals of 30-40 min, heat up to 90-95°C and react for 4-5 h; S3: After the reaction is completed, cool the reaction system to 35-40°C, slowly add 3-4 times the volume of acetone, centrifuge and collect the precipitate after standing and separating layers, then wash with a mixed solvent of ethanol and water 2-3 times to remove unreacted monomers and homopolymers and spray dry at 150-160°C to obtain the product.

[0024] As a preferred embodiment, the mass ratio of the activated lignin, aminosulfonic acid and EDTA is (10-12):(4-4.4):(0.05-0.1).

[0025] As a preferred embodiment, the mass ratio of the activated lignin, allyl glycidyl ether and glycidyl methacrylate is (10-12):(1.8-2.5):(1-1.5).

[0026] As a preferred embodiment, in the mixed solvent of ethanol and water, the volume ratio of ethanol to water is (3-4):1.

[0027] The addition of modified lignosulfonate can effectively improve the comprehensive performance of the water coal slurry additive. The linear polyether side chains introduced by modified lignosulfonate can provide long-chain steric hindrance to inhibit the agglomeration of coal particles, and bind to the hydrophobic regions on the coal surface through ester groups (-COOR) to enhance the adsorption strength. The ester groups can also partially decompose at high temperatures to generate free radicals to promote the micro-explosion of coal powder, increasing the specific surface area of the combustion reaction. On the other hand, the internal ether bonds and epoxy groups crosslink to form a three-dimensional network, inhibiting the movement of high-temperature segments and preventing the thermal decomposition of the additive; through amino sulfonic acid modification, the sulfonation degree is increased to enhance the electrostatic repulsion between coal particles. Overall, the addition of the above-mentioned modified lignosulfonate can balance the effects of dispersion-stabilization and combustion assistance, significantly improving the comprehensive performance of the additive.

[0028] Preparation method of a high-efficiency water coal slurry additive, specifically including the following steps: S1: Mix the auxiliary dispersant, stabilizer, interfacial agent, combustion aid and modified matrix agent in a high-speed disperser according to the ratio, and stir at a speed of 5000 - 6000 rpm for 20 - 30 min; S2: Transfer to a reaction kettle, heat up to 70 - 80 °C and keep warm for 1 - 2 h; S3: After the heat preservation is completed, naturally cool to room temperature, freeze-dry and grind the product, and pass through a 100 - 200 mesh sieve to obtain the finished product.

[0029] The beneficial effects of this application are:

[0030] 1. A high-efficiency water coal slurry additive provided in this application not only has excellent dispersion effects and good stability, etc., but also can simultaneously meet the requirements of the stability, fluidity and combustion performance of the water coal slurry system, thus greatly improving the storage and use quality of the water coal slurry system, and has very broad application potential.

[0031] 2. A high-efficiency water coal slurry additive provided in this application, the mixed system of the modified lignosulfonate and the auxiliary dispersant can effectively disperse coal powder particles, prevent particle agglomeration, improve the stability of the water coal slurry, and effectively prevent the water coal slurry from stratifying and precipitating through the stable internal system, improving the storage stability of the water coal slurry, and finally assisting in improving the fluidity and combustion performance of the water coal slurry through the combined action of the internal system.

[0032] 3. A high-efficiency water-coal slurry additive provided in the present application, through the addition of modified lignin sulfonate, the linear polyether side chain introduced can provide long-chain steric hindrance to inhibit coal particle agglomeration, and through the ester group (-COOR) combined with the hydrophobic area on the coal surface, the adsorption strength is enhanced, and the ester group can also partially decompose at high temperature to generate free radicals to promote coal powder micro-explosion and increase the specific surface area of ​​the combustion reaction. On the other hand, its internal ether bonds and epoxy groups are cross-linked to form a three-dimensional network, which inhibits high-temperature chain segment movement and prevents thermal decomposition of the additive; through aminosulfonic acid modification, the sulfonation degree is increased to enhance the electrostatic repulsion between coal particles. On the whole, the addition of the above-mentioned modified lignin sulfonate can take into account both dispersion-stabilization and combustion-supporting effects, greatly improving the comprehensive performance of the additive. DETAILED DESCRIPTION

[0033] In the specific implementation manner, specific implementation cases will be used to more intuitively display and illustrate the contents of the invention content of this application.

[0034] Example 1

[0035] The raw materials of the high-efficiency water-coal slurry additive, calculated by mass percentage, include: 30% auxiliary dispersant, 15% stabilizer, 8% interface agent, 2% combustion aid, and 45% modified matrix agent.

[0036] The auxiliary dispersant was acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, which was purchased as an industrial grade product sold by Shanghai Hongzhuang Chemical Technology Co., Ltd., China.

[0037] The stabilizer is a combination of sodium chloride and calcium chloride with a mass ratio of 3.5:1.

[0038] The interfacial agent is a composition of sodium dodecylbenzene sulfonate and cetearyl alcohol polyoxyethylene ether, with a mass ratio of 6.8:1.2; cetearyl alcohol polyoxyethylene ether was purchased from the O-50 product sold by Hai'an Petrochemical Plant in Jiangsu Province, China.

[0039] The combustion aid is potassium nitrate.

[0040] The modified matrix agent is modified lignosulfonate. Calculated by mass parts, the preparation method specifically includes the following steps: S1: Crush 11.5 parts of alkali lignin to 150 meshes, stir and process it with 90 parts of 5% hydrochloric acid solution at 60 °C for 2 h to remove residual lignosulfonate and ash, wash it with water to neutrality after centrifugation, and then mix it with ethanol at a mass ratio of 1:3, ultrasonically disperse it and then vacuum dry it to obtain activated lignin; S2: Add 10.2 parts of activated lignin, 4.2 parts of sulfamic acid and 0.08 part of EDTA to a high-pressure reactor, then add 80 parts of a mixed solvent of ethanol and water (the volume ratio of ethanol to water is 4:1), displace with nitrogen for 3 times until the oxygen content < 50 ppm, raise the temperature to 85 °C and dropwise add 10% dilute sulfuric acid to maintain the pH at 2.8, keep the temperature and react for 2 h, add 2.3 parts of allyl glycidyl ether and 1.4 parts of glycidyl methacrylate, and add 0.08 part of ammonium persulfate twice at intervals of 30 min, raise the temperature to 90 °C and react for 4 h; S3: After the reaction is completed, cool the reaction system to 40 °C, slowly add 3 times the volume of acetone, let it stand for layering and then centrifuge to collect the precipitate, then wash it 3 times with a mixed solvent of ethanol and water to remove unreacted monomers and homopolymers and spray dry it at 160 °C to obtain the product.

[0041] The preparation method of the high-efficiency coal water slurry additive specifically includes the following steps: S1: Mix the auxiliary dispersant, stabilizer, interfacial agent, combustion improver and modified matrix agent in proportion in a high-speed disperser and stir at a speed of 5000 rpm for 25 min; S2: Transfer it to a reaction kettle, raise the temperature to 75 °C and keep it warm for 1.5 h; S3: After the heat preservation is completed, naturally cool it to room temperature, freeze-dry and grind the product, and pass it through a 100-mesh sieve to complete the preparation.

[0042] Example 2

[0043] This example is only different from Example 1 in the following aspects: For the high-efficiency coal water slurry additive, calculated by mass percentage, the raw materials include: 35% of auxiliary dispersant, 12% of stabilizer, 10% of interfacial agent, 3% of combustion improver, and 40% of modified matrix agent.

[0044] Example 3

[0045] This example is only different from Example 1 in the following aspects: For the high-efficiency coal water slurry additive, calculated by mass percentage, the raw materials include: 27% of auxiliary dispersant, 18% of stabilizer, 10% of interfacial agent, 5% of combustion improver, and 40% of modified matrix agent.

[0046] Comparative Example 1

[0047] This comparative example is only different from Example 1 in the following aspects: For the coal water slurry additive, calculated by mass percentage, the raw materials include: 30% of naphthalene-based dispersant, 20% of sodium chloride, and 50% of sodium lignosulfonate.

[0048] The naphthalene-based dispersant was purchased as the FDN-C premium grade product sold by Shandong Wanshan Group Co., Ltd., China.

[0049] Comparative Example 2

[0050] This comparative example is only different from Example 1 in the following aspect: for the water coal slurry additive, by mass percentage, the raw materials include: 50% of polycarboxylate-based dispersant, 30% of sodium chloride, and 20% of sodium lignosulfonate.

[0051] The polycarboxylate-based dispersant was purchased as the PC-1055 product sold by Shanghai Hengchuang Chemical Co., Ltd., China.

[0052] Comparative Example 3

[0053] This comparative example is only different from Example 1 in the following aspect: the interfacial agent is a composition of sodium dodecylbenzenesulfonate and cetostearyl alcohol polyoxyethylene ether, and the mass ratio is 9.8:0.2.

[0054] Comparative Example 4

[0055] This comparative example is only different from Example 1 in the following aspect: the auxiliary dispersant is the sodium polycarboxylate product sold by Nanjing Chuhai New Material Technology Co., Ltd.

[0056] Comparative Example 5

[0057] This comparative example is only different from Example 1 in the following aspect: the modified matrix agent is modified lignosulfonate. By mass parts, the preparation method specifically includes the following steps: S1: Crush 11.5 parts of alkali lignin to 150 meshes, stir and treat it with 90 parts of 5% hydrochloric acid solution at 60°C for 2 h to remove residual lignosulfonate and ash, wash it with water to neutral after centrifugation, and then mix it with ethanol at a mass ratio of 1:3, ultrasonically disperse it and then vacuum dry it to obtain activated lignin; S2: Add 20.5 parts of activated lignin, 3.5 parts of aminosulfonic acid and 0.08 part of EDTA to a high-pressure reactor, then add 80 parts of ethanol and water mixed solvent (the volume ratio of ethanol to water is 4:1), displace it with nitrogen for 3 times until the oxygen content < 50 ppm, heat it up to 85°C and dropwise add 10% dilute sulfuric acid to maintain the pH at 2.8, keep the temperature for reaction for 2 h, add 1.2 parts of allyl glycidyl ether and 3.5 parts of glycidyl methacrylate, and add 0.08 part of ammonium persulfate twice at an interval of 30 min, heat it up to 90°C and react for 4 h; S3: After the reaction is completed, cool the reaction system to 40°C, slowly add 3 times the volume of acetone, let it stand for layering and then centrifuge to collect the precipitate, and then wash it 3 times with ethanol and water mixed solvent to remove unreacted monomers and homopolymers and spray dry it at 160°C to obtain.

[0058] Comparative Example 6

[0059] This comparative example is only different from Example 1 in the following aspects: the modified matrix agent is modified lignosulfonate. By mass, the preparation method specifically includes the following steps: S1: Crush 11.5 parts of alkali lignin to 150 mesh, stir and treat it with 90 parts of 5% hydrochloric acid solution at 60°C for 2 h to remove residual lignosulfonate and ash. After centrifugation, wash it with water until neutral, and then mix it with ethanol at a mass ratio of 1:3. After ultrasonic dispersion, dry it under vacuum to obtain activated lignin; S2: Add 18.5 parts of activated lignin, 4.1 parts of aminosulfonic acid and 0.06 parts of EDTA to a high-pressure reactor, then add 80 parts of a mixed solvent of ethanol and water (the volume ratio of ethanol to water is 4:1), displace with nitrogen 3 times until the oxygen content < 50 ppm, heat up to 85°C and dropwise add 10% dilute sulfuric acid to maintain the pH at 2.8, keep the temperature for reaction for 2 h, add 5.5 parts of allyl glycidyl ether and 0.3 parts of glycidyl methacrylate, and add 0.08 parts of ammonium persulfate twice at intervals of 30 min, and heat up to 90°C for reaction for 4 h; S3: After the reaction is completed, cool the reaction system to 40°C, slowly add 3 times the volume of acetone, centrifuge and collect the precipitate after standing and separating layers, then wash it 3 times with a mixed solvent of ethanol and water to remove unreacted monomers and homopolymers, and spray dry at 160°C to obtain the product.

[0060] Performance evaluation

[0061] This performance evaluation uses the company's own instrument and equipment, and uses wet coal grinding to simulate the on-site device to make a slurry property evaluation. The experimental operation process of wet pulping is as follows:

[0062] (1) Use a fully sealed hammer crusher to crush the raw coal provided on site;

[0063] (2) Measure the total water content of the crushed raw coal according to the national standard for later use;

[0064] (3) Configure the ratio of grinding media according to the conventional particle size distribution of the water coal slurry;

[0065] (4) Set the target concentration to 62.5 wt% coal, 0.2 wt% additives prepared in the examples and comparative examples, and make up the balance with water. This pulping is carried out as a slurry property test with 300 g of coal slurry. Weigh coal, additives and water accurately according to the preparation requirements to prepare the coal slurry;

[0066] (5) Set the coal grinding time according to the grindability index and particle size distribution, and the water coal slurry is obtained after the mill operation ends;

[0067] (6) Test the apparent viscosity, concentration and fluidity of the prepared coal slurry, and let it stand for 24 hours to measure the stability.

[0068] Add the water coal slurry additives prepared in the examples and comparative examples to the water coal slurry respectively, and conduct performance tests on the water coal slurry concentration, viscosity, stability and fluidity:

[0069] (1) Coal slurry concentration

[0070] The oven drying method is used to measure the coal slurry concentration. Set and heat the blast drying oven to 105°C (±2°C). Weigh 3g ± 0.2g (accurate to 0.001g) of the coal slurry sample into a weighing bottle that has been dried to a constant weight. The heating time is 1h. Cool the desiccator to room temperature and weigh. The checking drying time is 30min, until the weight remains constant or returns to the original weight. Calculate the coal slurry concentration according to the formula. The reference standard is GB / T 18856.2 - 2008.

[0071] (2) Coal slurry viscosity

[0072] Use an NXS-4C type coal water slurry viscometer to measure the coal slurry viscosity. Select the automatic gear to measure the coal slurry viscosity. The reference standard is GB / T 18856.4 - 2008.

[0073] (3) Coal slurry fluidity

[0074] The visual inspection method is adopted. The coal slurry is divided into three grades: A (continuous flow), B (intermittent flow), and C (almost non-flowing or non-flowing). Grade A is a thin fluid with continuous, smooth, and uninterrupted flow; Grade B is a thick fluid with relatively continuous flow and an uneven fluid surface; Grade C can flow well only with the help of external force or is in a muddy state and cannot form a slurry and cannot flow. "+" indicates better fluidity in a certain grade; "-" indicates poorer fluidity in a certain grade.

[0075] (4) Coal slurry stability

[0076] Pour the coal slurry into a 100mL graduated cylinder, let it stand for 24h, then read the scale value to measure the water separation rate. Conduct a dropping rod experiment with a glass rod and observe the precipitation of the coal slurry to measure the stability of the coal slurry. The reference standard is GB / T18856.5—2008. That is, after the measured coal water slurry sample is sealed and left standing for 24h, the rod insertion method is used for observation. The determination of the stability of the coal water slurry is divided into four grades, and the specific situations are as follows:

[0077] Grade A - The best stability, the slurry is evenly distributed, no water separation, no precipitation, and the flow state is as good as the original after stirring;

[0078] Grade B - Better stability, no precipitation or a small amount of soft precipitation, very little water separation and slight uneven distribution of slurry density may occur;

[0079] Grade C - Poorer stability, water separation occurs, the slurry density is unevenly distributed, and precipitation is serious, but after being stirred, a uniform slurry can be regenerated;

[0080] Grade D - The worst stability, the slurry density is significantly unevenly distributed, a lot of water separation, hard precipitation, and cannot be regenerated.

[0081] Table 1 Performance Evaluation Table

[0082]

[0083] From the final performance test results of the examples and comparative examples, the pulp-forming performance of Comparative Examples 1-6 is poorer than that of the examples. The examples adopt better technical solutions, and through the combined action of modified lignosulfonate and auxiliary dispersant, the coal powder particles are effectively dispersed, preventing particle agglomeration, improving the stability of the water-coal slurry, and effectively preventing the water-coal slurry from stratifying and precipitating through a stable internal system, improving the storage stability of the water-coal slurry. And through the combined action of the internal system, it finally helps to improve the fluidity and combustion performance of the water-coal slurry.

Claims

1. An efficient water coal slurry additive, characterized in that: By mass percentage, the raw materials include: 20-40% of auxiliary dispersant, 10-20% of stabilizer, 5-10% of interfacial agent, 1-5% of combustion promoter, and the balance is made up by the modified matrix agent; The auxiliary dispersant is an acrylic-acrylamide copolymer; The interfacial agent is a composition of sodium dodecylbenzenesulfonate and cetostearyl alcohol polyoxyethylene ether, and the mass ratio is (6-8):(1-1.5); The modified matrix agent is modified lignosulfonate, and the preparation method includes: S1: Crush the alkali lignin, add hydrochloric acid solution and stir to remove residual lignosulfonate and ash, wash with water to neutral after centrifugation, and then mix with ethanol, ultrasonically disperse and vacuum dry to obtain activated lignin; S2: Add the activated lignin, aminosulfonic acid and EDTA to a high-pressure reactor, then add a mixed solvent of ethanol and water, heat up and keep the temperature for reaction, and then add allyl glycidyl ether, glycidyl methacrylate and ammonium persulfate, heat up and keep the temperature for reaction; S3: After the reaction is completed, cool the reaction system, slowly add acetone, centrifuge to collect the precipitate after standing and separating layers, and then wash with a mixed solvent of ethanol and water and spray dry at high temperature to obtain the product.

2. The high-efficiency coal water slurry additive according to claim 1, wherein: The mass ratio of the modified matrix agent, auxiliary dispersant and stabilizer is (35-45):(25-35):(12-18).

3. The high-efficiency coal water slurry additive according to claim 2, wherein: The stabilizer is at least one of sodium chloride, calcium chloride, sodium sulfate and calcium sulfate.

4. The high-efficiency coal water slurry additive according to claim 3, wherein: The acrylic-acrylamide copolymer is acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer.

5. The high-efficiency coal water slurry additive according to claim 4, wherein: The combustion promoter is at least one of potassium nitrate, sodium nitrate, potassium permanganate, barium nitrate and hydrogen peroxide.

6. The high-efficiency coal water slurry additive according to claim 5, wherein: The preparation method of the modified lignosulfonate specifically includes the following steps: S1: Crush the alkali lignin to 120-200 mesh, stir with 5-8% hydrochloric acid solution at 60-65°C for 2-3 h to remove residual lignosulfonate and ash, wash with water to neutral after centrifugation, and then mix with ethanol at a mass ratio of 1:(3-4), ultrasonically disperse and vacuum dry to obtain activated lignin; S2: Add the activated lignin, aminosulfonic acid and EDTA to a high-pressure reactor, then add a mixed solvent of ethanol and water, displace with nitrogen 3 times until the oxygen content <50 ppm, heat up to 80-85°C and add dilute sulfuric acid dropwise to maintain the pH at 2.5-3.0, keep the temperature for reaction for 2-3 h, add allyl glycidyl ether and glycidyl methacrylate, and add ammonium persulfate evenly in two portions at intervals of 30-40 min, heat up to 90-95°C and react for 4-5 h; S3: After the reaction is completed, cool the reaction system to 35-40°C, slowly add 3-4 times the volume of acetone, centrifuge to collect the precipitate after standing and separating layers, and then wash with a mixed solvent of ethanol and water 2-3 times to remove unreacted monomers and homopolymers and spray dry at 150-160°C to obtain the product.

7. The high-efficiency coal water slurry additive according to claim 6, characterized in that: The mass ratio of the activated lignin, aminosulfonic acid and EDTA is (10-12):(4-4.4):(0.05-0.1).

8. The high-efficiency coal water slurry additive according to claim 7, wherein: The mass ratio of the activated lignin, allyl glycidyl ether and glycidyl methacrylate is (10 - 12):(1.8 - 2.5):(1 - 1.5).

9. The high-efficiency coal water slurry additive according to claim 8, wherein: The stabilizer is a composition of sodium chloride and calcium chloride or sodium sulfate, and the mass ratio is (3 - 4):(0.8 - 1.4).

10. A preparation method of the high-efficiency water coal slurry additive according to any one of claims 1 to 9, characterized in that: Specifically, it includes the following steps: S1: Mix the auxiliary dispersant, stabilizer, interfacial agent, flame retardant and modified matrix agent in proportion in a high-speed disperser, and stir at a speed of 5000 - 6000 rpm for 20 - 30 min; S2: Transfer to a reaction kettle, heat up to 70 - 80 °C and keep warm for 1 - 2 h; S3: After the heat preservation is completed, naturally cool to room temperature, freeze-dry and grind the product, and pass through a 100 - 200 mesh sieve to obtain the finished product.

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