Additive composition for coal water slurry

Abstract

The invention discloses an additive composition for coal water slurry, and belongs to the technical field of coal chemical industry. The additive composition for the coal water slurry, provided by the invention, comprises lignosulfonate, inorganic salt and an acid-base regulator. According to the invention, lignin is grafted and sulfonated, such that lignosulfonate with high relative molecular mass is prepared. The specific preparation method comprises the following steps: by taking lignin as a raw material, reacting with formaldehyde, acetone and sodium sulfanilate under normal pressure, and introducing a sulfonated branched chain into a lignin molecular structure, so as to prepare the high-sulfonation-degree comb-shaped branched-chain lignosulfonate with the molecular weight of 10000-50000 Da. The lignosulfonate, the inorganic salt and the acid-base regulator are added into the coal mill and mixed with the coal or / and the coal coke or / and the petroleum coke and the water for grinding to prepare the coal water slurry, so that the flowability and the stability of the coal water slurry are improved, the viscosity of the coal water slurry is reduced, and the concentration of the coal water slurry is improved.

Description

Technical Field

[0001] The present invention relates to the field of coal chemical industry, in particular to an additive composition for coal-water slurry, and further to a method for preparing a high-molecular weight lignin sulfonate with a high degree of sulfonation and comb-shaped branches that helps improve the dispersibility of coal particles in coal-water slurry. Background Art

[0002] Coal-water slurry is one of the important clean coal technologies. It is a coal-water suspension made by mixing coal particles of a certain fineness, water and additives, also known as coal-water slurry. Its application requires good fluidity, good stability, low viscosity and high concentration.

[0003] At present, there are two main categories of additives for water-coal slurry. One category is lignin, such as sodium lignin sulfonate, which has low cost and poor dispersibility. The water-coal slurry prepared has good stability, poor fluidity, high viscosity and low concentration. The other category is sulfonates, such as sodium naphthalenesulfonate formaldehyde condensate, which has high cost and good dispersibility. The water-coal slurry prepared has good fluidity, low viscosity, high concentration, poor stability and easy precipitation. In addition, there is a class of modified lignin, which introduces sulfonic acid groups into the molecular structure of lignin through sulfonation reaction to improve the water solubility and dispersibility of lignin. Amel Kamouna et al. separated and purified lignin, added sodium sulfite and formaldehyde, reacted for 3 to 6 hours at pH = 7 to 9 and temperature of 130 to 160 ° C, and obtained lignin sulfonate. Nakano J. prepared lignin sulfonate by purification, compounding and other methods after sulfomethylation of lignin. Roy TK et al. obtained lignin sulfonate by two-step sulfonation of lignin at 140-150°C, which has good dispersibility. Yasuyuki Matsushita et al. first activated lignin with phenol, and then modified it by sulfomethylation, hydroxymethylation and aromatic sulfonation. Chang Dayong et al. prepared lignin sulfonate by sulfonation. Fan Yaobo et al. prepared lignin sulfonate by sulfonation modification of lignin. Patent US4239550 prepared lignin sulfonate by polycondensation and sulfonation of sulfonated lignin and ring sulfonation or sulfomethyl aromatic derivatives. Patent US4367094 used sulfonated lignin with no less than 0.2 carboxyl groups and 0.1 sulfonate groups on each phenylpropane unit in the lignin molecular structure as lignin sulfonate. Patent CN02100805.1 discloses the preparation of lignin sulfonate by sulfonation reaction of lignin with formaldehyde and sulfite at normal pressure. Patent CN1177617A discloses a dispersant, which is prepared by introducing carboxyl groups through electro-oxidation of lignin, followed by sulfomethylation reaction at 100-175°C. Patent CN200510032657.7 prepares lignin sulfonate through oxidation, sulfonation and condensation reaction of lignin. Patent CN200410044834.9 prepares lignin sulfonate through catalysis, high temperature sulfonation, compounding and other modification of lignin. Patent CN200910040399.5 prepares lignin sulfonate by reacting lignin with dihydroxy ketone, introducing side chains, and then sulfonation reaction.

[0004] However, the above-mentioned prior arts all have shortcomings. In view of this, the present invention proposes an additive composition for water-coal slurry, and further proposes a method for preparing a high-molecular weight lignin sulfonate with a high degree of sulfonation and comb-shaped branches that helps to improve the dispersion performance of coal particles in water-coal slurry. Summary of the invention

[0005] The purpose of the present invention is to provide an additive composition for water-coal slurry to solve the problems raised in the background technology. The water-coal slurry prepared by using the additive composition proposed by the present invention has the characteristics of good fluidity, good stability, low viscosity and high concentration.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An additive composition for coal-water slurry, comprising lignin sulfonate, an inorganic salt and an acid-base regulator; wherein the lignin sulfonate has the following structure:

[0008]

[0009] In the structural formula [1] of the lignin sulfonate, L is a lignin molecule, M is sodium or potassium, and a, b, c, d, and n are integers in the range of 1 to 100;

[0010] The preparation method of the lignin sulfonate comprises the following steps:

[0011] (1) dissolving a predetermined amount of a sulfonating agent in water and stirring to form a mixed solution I;

[0012] (2) adding a predetermined amount of formaldehyde to the mixed solution I prepared in step (1) under stirring to react and form a mixed solution II;

[0013] (3) adding a predetermined amount of sulfonating agent and catalyst to the mixed solution II prepared in step (2) under stirring to react and form a mixed solution III;

[0014] (4) adding a catalyst to a predetermined amount of formaldehyde under stirring, and then slowly adding a predetermined amount of acetone to react to form a mixed solution FA; slowly adding a predetermined amount of mixed solution FA to the mixed solution III prepared in step (3) under stirring to react to form a mixed solution IV;

[0015] (5) slowly adding a predetermined amount of formaldehyde to the mixed solution IV prepared in step (4) under stirring to react and form a mixed solution V;

[0016] (6) adding a predetermined amount of water, lignin, p-aminobenzenesulfonate and a catalyst to the mixed solution V prepared in step (5) under stirring to react and form a mixed solution VI;

[0017] (7) Slowly add a predetermined amount of formaldehyde to the mixed solution VI prepared in step (6) under stirring to react and form a complete reactant.

[0018] Preferably, the sulfonating agent includes but is not limited to one or more of sodium sulfite, sodium bisulfite, sodium pyrosulfite, potassium sulfite, potassium bisulfite, and potassium pyrosulfite.

[0019] Preferably, the catalyst includes but is not limited to one or both of sodium hydroxide and potassium hydroxide.

[0020] Preferably, the molecular weight of the lignin sulfonate is 10,000 to 50,000 Da.

[0021] Preferably, the inorganic salt includes, but is not limited to, one or more of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium phosphate, potassium phosphate, sodium metaphosphate, potassium metaphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium tripolyphosphate, and potassium tripolyphosphate.

[0022] Preferably, the acid-base regulator includes but is not limited to one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

[0023] Preferably, based on the mass percentage of the composition, the mass percentage of the lignin sulfonate is 50-99wt%, the mass percentage of the inorganic salt is 1-50wt%, and the mass percentage of the acid-base regulator is 0.01-1wt%.

[0024] Preferably, the coal-water slurry is a suspension comprising coal and / or coal tar and / or petroleum coke, water and additives; the mass percentage of the additive composition in the coal-water slurry is 0.05-0.5wt% based on the mass percentage of the composition.

[0025] Compared with the prior art, the present invention provides an additive composition for coal water slurry, which has the following beneficial effects:

[0026] (1) The present invention creatively improves the dispersibility and stability of the coal water slurry additive composition by preparing a high molecular weight lignin sulfonate with a high degree of sulfonation and comb-shaped branches. First, the sulfonating agent is dissolved in water to undergo a hydrolysis reaction to obtain bisulfite ions HSO3 - ; Secondly, formaldehyde and bisulfite ion HSO3 -A nucleophilic addition reaction occurs, and the nucleophilic center is not an oxygen atom but a sulfur atom, and the resulting addition product is not a sulfate ester but an α-hydroxysulfonate HOCH2SO3M; again, increasing the concentration of the sulfonating agent and the catalyst to promote the nucleophilic addition reaction of formaldehyde and the bisulfite ion to obtain more α-hydroxysulfonate HOCH2SO3M; then, slowly adding a predetermined amount of acetone to a predetermined amount of formaldehyde to reduce the self-condensation reaction of acetone; formaldehyde and acetone undergo an aldehyde-ketone condensation reaction to obtain an α, β-unsaturated ketone CH2=CHCOCH3; the α, β-unsaturated ketone CH2=CHCOCH3 undergoes a condensation reaction with the α-hydroxysulfonate HOCH2SO3M to obtain CH2=CHCOCH2CH2SO3M; then, formaldehyde and CH2=CHCOCH2CH2SO3M undergo an aldehyde-ketone condensation reaction to obtain CH2=CHC(OH)(CHO)CH2CH2SO3M and CH2=CHC(CO)CH2CH2SO3M. Finally, lignin undergoes polymerization reaction with CH2=CHCOCH3, CH2=CHCOCH2CH2SO3M, CH2=CHC(OH)(CHO)CH2CH2SO3M, and CH2=CHC(CO)CH2CH2SO3M, and at the same time, lignin undergoes condensation reaction with p-aminobenzenesulfonate and formaldehyde to obtain high molecular weight lignin sulfonate with high sulfonation degree and comb-shaped branches; during the preparation process, it is very important to add formaldehyde to CH2=CHCOCH2CH2SO3M to undergo aldehyde-ketone condensation reaction to obtain CH2=CHC(OH)(CHO)CH2CH2SO3M and CH2=CHC(CO)CH2CH2SO3M; on this basis, comb-shaped lignin sulfonate is finally obtained by polymerization reaction; the site of the polymerization reaction is mainly at the ortho position of the phenolic hydroxyl group of the benzene ring, and the present invention connects the high sulfonation degree branch in the lignin phenylpropane structure through graft polymerization reaction, thereby reducing the steric hindrance formed by the methoxy group on the phenylpropane to the sulfonation reaction, and also reducing the competitive hindrance of the sulfonation reaction to the polymerization reaction.

[0027] (2) The present invention creatively controls the pH value of the water-coal slurry by using an acid-base regulator to make the water-coal slurry alkaline. On the one hand, it prevents the aggregation and cementation of humic acid organic matter, which can reduce the viscosity of the water-coal slurry. The effect is more significant when combined with inorganic salts. On the other hand, the water-coal slurry is alkaline, which can reduce corrosion to equipment and pipelines.

[0028] (3) The present invention creatively increases the concentration of monovalent metal cations in water-coal slurry by adding inorganic salts, and utilizes electrostatic repulsion effect, indirect cation replacement reaction, and ion hydration effect to improve the viscosity and flowability of water-coal slurry. Inorganic salts with small molecular weight and high ion charge can increase the surface potential energy of coal particles in water-coal slurry, increase the double-layer repulsion potential energy, increase the repulsion force between particles, and prevent particles from approaching each other. The monovalent metal cations in inorganic salts have the strongest hydration ability and the weakest adsorption ability. Therefore, when inorganic salts are added to water-coal slurry, on the one hand, less monovalent metal cations enter the adsorption layer of coal particles, the charge density on the surface of coal particles increases, the double-layer thickness of coal particles increases, the Zeta potential of water-coal slurry increases, and the repulsion force between particles increases, which will reduce the viscosity of water-coal slurry and increase the flowability. On the other hand, monovalent metal cations replace calcium and magnesium ions adsorbed by coal particles. Different ions adsorb different numbers of water molecules when hydrated in solution. Calcium and magnesium ions adsorb 10 to 12 water molecules, and potassium and sodium ions adsorb 4 to 5 water molecules. Monovalent metal cations have strong hydration ability. After replacement, they release the water adsorbed by calcium and magnesium ions with a large number of molecules in the hydration layer, increase the content of free water in the water-coal slurry, and achieve the effect of reducing viscosity and increasing fluidity.

[0029] The lignin sulfonate used in the additive composition for coal water slurry proposed by the present invention is a high molecular compound with a phenylpropane hydrophobic skeleton and a sulfonic acid group as the main hydrophilic group. The sulfonation reaction gives it good water solubility, surface activity and reaction activity, and the polymerization reaction gives it a higher relative molecular mass and good adsorption and dispersion performance. The relative molecular mass of the lignin sulfonate is controlled at 10000-50000Da, and it is combined with an inorganic salt and an acid-base regulator to form a coal water slurry additive, which has good dispersibility and stability, improves the fluidity and stability of the coal water slurry, reduces the viscosity of the coal water slurry, and increases the concentration of the coal water slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of the preparation method of the lignin sulfonate mentioned in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] The present invention provides an additive composition for coal water slurry, comprising lignin sulfonate, an inorganic salt and an acid-base regulator, wherein the lignin sulfonate has the following structure:

[0033]

[0034] In the structural formula [1] of lignin sulfonate, L is a lignin molecule, M is sodium or potassium, and a, b, c, d, and n are integers in the range of 1 to 100;

[0035] The preparation method of the above-mentioned lignin sulfonate comprises the following steps:

[0036] (1) dissolving a predetermined amount of a sulfonating agent in water and stirring to form a mixed solution I;

[0037] (2) adding a predetermined amount of formaldehyde to the mixed solution I under stirring to react and form a mixed solution II;

[0038] (3) adding a predetermined amount of sulfonating agent and catalyst to the mixed solution II under stirring to react and form a mixed solution III;

[0039] (4) under stirring, adding a catalyst to a predetermined amount of formaldehyde, and then slowly adding a predetermined amount of acetone, reacting to form a mixed solution FA; under stirring, slowly adding a predetermined amount of mixed solution FA to the mixed solution III, reacting to form a mixed solution IV;

[0040] (5) slowly adding a predetermined amount of formaldehyde to the mixed solution IV under stirring to react and form a mixed solution V;

[0041] (6) adding a predetermined amount of water, lignin, p-aminobenzenesulfonate and a catalyst to the mixed solution V under stirring to react and form a mixed solution VI;

[0042] (7) Slowly add a predetermined amount of formaldehyde to the mixed solution VI under stirring to react and form a complete reactant.

[0043] In the above preparation process, the sulfonating agent selected includes but is not limited to one or more of sodium sulfite, sodium bisulfite, sodium pyrosulfite, potassium sulfite, potassium bisulfite, and potassium pyrosulfite.

[0044] The catalyst selected includes but is not limited to one or both of sodium hydroxide and potassium hydroxide.

[0045] The molecular weight of the above lignin sulfonate is 10000-50000Da.

[0046] The selected inorganic salts include, but are not limited to, one or more of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium phosphate, potassium phosphate, sodium metaphosphate, potassium metaphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium tripolyphosphate, and potassium tripolyphosphate.

[0047] The acid-base regulator selected includes but is not limited to one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0048] The mass percentage of the lignin sulfonate is 50-99wt%, the mass percentage of the inorganic salt is 1-50wt%, and the mass percentage of the acid-base regulator is 0.01-1wt%.

[0049] The above-mentioned coal-water slurry is a suspension comprising coal and / or coal coke and / or petroleum coke, water and additives, and the mass percentage of the additive composition in the coal-water slurry is 0.05-0.5wt%.

[0050] The additive composition of the present invention can be made into a solid powder mixture and added to a ball mill or rod mill in the form of a powder, or it can be prepared into an aqueous solution and added to a ball mill or rod mill in the form of an aqueous solution, mixed with coal and / or coal coke and / or petroleum coke and water and ground to form a water-coal slurry.

[0051] In the present invention, the sources of raw materials in the embodiments and comparative examples are listed as follows:

[0052] Sodium sulfite, sodium pyrosulfite, formaldehyde (37 wt%), acetone, sodium p-aminobenzenesulfonate, sodium hydroxide, sodium sulfate, sodium phosphate, sodium tripolyphosphate are from Sinopharm Chemical Reagent Co., Ltd.; lignin, sodium lignin sulfonate, sulfonated acetone formaldehyde condensate, sodium p-aminobenzenesulfonate phenol formaldehyde condensate, sodium naphthalenesulfonate formaldehyde condensate, sodium melamine sulfonate formaldehyde condensate are from commercial sources. The additive composition for water-coal slurry proposed by the present invention is described below in conjunction with specific examples, and the specific contents are as follows.

[0053] Embodiment 1:

[0054] The above operation method was used to prepare lignin sulfonate, and then 70 g of formaldehyde was added to another reaction bottle, stirred, 20% sodium hydroxide was added to adjust the pH to 12, 58 g of acetone was added dropwise (0.5 hour), and the mixture was reacted at 40° C. for 0.5 hour to obtain a mixed solution FA.

[0055] Add 40g sodium sulfite to 250g water, stir, heat to 40℃ and react for 0.5 hours; drip (0.5 hours) 55g formaldehyde, react at 40℃ for 1 hour; add 8g sodium pyrosulfite, add 20% sodium hydroxide to adjust pH=12, react at 40℃ for 0.5 hours, and heat to 60℃; drip (1 hour) all the mixed solution FA, react at 60℃ for 1 hour; drip (2 hours) 55g formaldehyde, the mixed solution gradually heats to 90℃ during the dripping process, and react at 90℃ for 1 hour; add 850g water, 200g lignin, 200g sodium p-aminobenzenesulfonate, add 20% sodium hydroxide to adjust pH=9; drip (3 hours) 105g formaldehyde, react at 90℃ for 2 hours; stop heating, stop stirring when cooled to 40℃, and obtain sodium lignin sulfonate aqueous solution product. The product has a solid content of 32.3% and a molecular weight of 25880Da.

[0056] Embodiment 2:

[0057] Based on Example 1, but different in that the product prepared in Example 1 is spray-dried to obtain a sodium lignin sulfonate powder product with a moisture content of 4.5% and a molecular weight of 25860 Da.

[0058] Embodiment 3:

[0059] Based on Example 1-2, but different in that Jinjitan coal is used as raw material, ground, sieved, graded, mixed, and prepared into a test coal sample, and the particle size distribution test results are shown in the following table.

[0060]

[0061]

[0062] Embodiment 4~8:

[0063] By changing the mass percentage of the additive components in the examples, different additive compositions were prepared.

[0064] Example 4 Example 5 Example 6 Example 7 Example 8 Example 1 Product (wt%) 50 Example 2 Product (wt%) 85 98 85 85 Sodium sulfate (wt%) 49.9 14.5 1 Sodium phosphate (wt%) 14.5 Sodium triphosphate (wt%) 14.5 Sodium hydroxide (wt%) 0.1 0.5 1 0.5 0.5

[0065] Comparative Examples 1 to 5:

[0066] Different additive compositions were prepared by changing the mass percentage of the additive components of the control example.

[0067] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 LS (wt%) 85 SAF (wt%) 85 ASP (wt%) 85 SNF (wt%) 85 SMF (wt%) 85 Sodium sulfate (wt%) 14.5 14.5 14.5 14.5 14.5 Sodium hydroxide (wt%) 0.5 0.5 0.5 0.5 0.5

[0068] In the above table, LS is sodium lignin sulfonate, SAF is sulfonated acetone formaldehyde condensate, ASP is sodium p-aminobenzenesulfonate phenol formaldehyde condensate, SNF is sodium naphthalenesulfonate formaldehyde condensate, and SMF is sodium melamine sulfonate formaldehyde condensate.

[0069] A water-coal slurry containing the materials from Examples 4 to 8 and Comparative Examples 1 to 5 was prepared as follows:

[0070] A determined amount of the coal water slurry additive composition is added to a determined amount of water, mixed evenly, a determined amount of the test coal sample of Example 3 is added thereto, stirred evenly, sealed with a plastic film, and allowed to stand at 25° C. for 15 minutes to prepare a coal water slurry.

[0071] The concentration, viscosity, fluidity and stability of the prepared coal water slurry are tested to determine the effect of the additive composition. In the present invention, the test method for the performance of the coal water slurry is listed as follows:

[0072] Determination of coal water slurry concentration:

[0073] The concentration of coal water slurry is determined according to GB / T 18856.2-2008.

[0074] Determination of viscosity of coal water slurry:

[0075] The viscosity of coal water slurry was determined according to GB / T 18856.4-2008.

[0076] Determination of fluidity of coal water slurry:

[0077] Place a glass funnel on top of a 100mL measuring cylinder, insert the lower end of the funnel into the measuring cylinder 2 to 3cm, and make the funnel coaxial with the measuring cylinder. Quickly pour 150.0g of water-coal slurry into the funnel and observe the outflow of the water-coal slurry from the beginning to the outflow of 100mL. If the water-coal slurry flows out continuously, it is judged as A. If the water-coal slurry flows out intermittently, it is judged as B. If the water-coal slurry does not flow out, it is judged as C.

[0078] The stability test method of coal water slurry is:

[0079] Use a beaker with a diameter of 90 mm to measure 300.0 g of water-coal slurry, stir evenly, seal with plastic film, and let it stand in an environment of 25°C for 24 hours. The water-coal slurry is divided into two layers, the upper layer is clean water, and the lower layer is coal slurry. Remove the sealing plastic film, suck out the upper layer of clean water with a straw and weigh Wg, and use a smooth glass rod (diameter 6 mm, weight 149.0~151.0 g) to vertically contact the upper liquid surface of the lower layer of coal slurry. Allow it to fall freely without applying external force, and record the time from the beginning of the glass rod falling to the bottom of the cup. If the time for the glass rod to fall to the bottom of the cup exceeds 30 seconds, it is judged that the rod cannot fall and is recorded as NA. Among them, the water separation rate calculation formula is:

[0080] Water separation rate (%) = W / 300×100 (%).

[0081] The specific test results are shown in the following table.

[0082]

[0083]

[0084] It can be seen from the above table that the additive composition of the present invention, which contains high-relative molecular weight, high-sulfonation degree comb-shaped branched lignin sulfonate, can provide better fluidity, lower viscosity, and better concentration compared with commercially available sodium lignin sulfonate; compared with sulfonated acetone formaldehyde condensate, sodium p-aminobenzenesulfonate phenol formaldehyde condensate, sodium naphthalenesulfonate formaldehyde condensate, and sodium melamine sulfonate formaldehyde condensate, it can provide excellent stability and prevent precipitation. Compared with the water-coal slurry additive provided by the prior art, the composition of the present invention can provide better dispersibility and stability.

[0085] The above only describes the preferred embodiments of the subject matter of the present application, including the best mode known to the inventors for realizing the claimed subject matter, and these preferred embodiments should not be regarded as limitations on the present invention, and the scope of protection of the present invention should be based on the scope defined by the claims. Through the detailed description herein, any modifications made by ordinary technicians in this field under the guidance of the above preferred embodiments should be considered obvious. Therefore, for ordinary technicians in this technical field, without departing from the spirit and scope of the present invention, several step adjustments, simple technical replacements, improvements and modifications made should also be regarded as the scope of protection of the present invention.

Claims

1. An additive composition for coal water slurry, characterized in that: It comprises lignin sulfonate, inorganic salt and acid-base regulator; wherein the lignin sulfonate has the following structure: In the structural formula [1] of the lignin sulfonate, L is a lignin molecule, M is sodium or potassium, and a, b, c, d, and n are integers in the range of 1 to 100; The preparation method of the lignin sulfonate comprises the following steps: (1) dissolving a predetermined amount of a sulfonating agent in water and stirring to form a mixed solution I; (2) adding a predetermined amount of formaldehyde to the mixed solution I prepared in step (1) under stirring to react and form a mixed solution II; (3) adding a predetermined amount of sulfonating agent and catalyst to the mixed solution II prepared in step (2) under stirring to react and form a mixed solution III; (4) adding a catalyst to a predetermined amount of formaldehyde under stirring, and then slowly adding a predetermined amount of acetone to react to form a mixed solution FA; slowly adding a predetermined amount of mixed solution FA to the mixed solution III prepared in step (3) under stirring to react to form a mixed solution IV; (5) slowly adding a predetermined amount of formaldehyde to the mixed solution IV prepared in step (4) under stirring to react and form a mixed solution V; (6) adding a predetermined amount of water, lignin, p-aminobenzenesulfonate and a catalyst to the mixed solution V prepared in step (5) under stirring to react and form a mixed solution VI; (7) Slowly add a predetermined amount of formaldehyde to the mixed solution VI prepared in step (6) under stirring to react and form a complete reactant.

2. The additive composition for coal water slurry according to claim 1, characterized in that: The sulfonating agent includes, but is not limited to, one or more of sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium sulfite, potassium bisulfite, and potassium metabisulfite.

3. The additive composition for coal water slurry according to claim 1, characterized in that: The catalyst includes but is not limited to one or both of sodium hydroxide and potassium hydroxide.

4. The additive composition for coal water slurry according to claim 1, characterized in that: The molecular weight of the lignin sulfonate is 10000-50000Da.

5. The additive composition for coal water slurry according to claim 1, characterized in that: The inorganic salt includes, but is not limited to, one or more of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium phosphate, potassium phosphate, sodium metaphosphate, potassium metaphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium tripolyphosphate, and potassium tripolyphosphate.

6. The additive composition for coal water slurry according to claim 1, characterized in that: The acid-base regulator includes but is not limited to one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

7. The additive composition for coal water slurry according to claim 1, characterized in that: Calculated by weight percentage of the composition, the weight percentage of the lignin sulfonate is 50-99wt%, the weight percentage of the inorganic salt is 1-50wt%, and the weight percentage of the acid-base regulator is 0.01-1wt%.

8. The additive composition for coal water slurry according to claim 1, characterized in that: The coal-water slurry is a suspension comprising coal and / or coal tar and / or petroleum coke, water and additives; in terms of composition mass percentage, the mass percentage of the additive composition in the coal-water slurry is 0.05-0.5wt%.

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