Environmentally friendly composite coal water slurry additive and preparation method thereof

Abstract

The invention discloses a kind of environmentally friendly composite water-coal slurry additive and preparation method thereof, the preparation method comprises the steps:Fatty alcohol polyoxyethylene ether is added to water, stirred at temperature 40 50 DEG C, sodium gluconate is added, maintenance system pH value is 7 8, stirring, obtain prefabricated material;It is regulated that papermaking waste liquid pH value is 5 7, initiator, FeSO4 7H2O are added and mixed, microwave treatment is carried out, amino-terminated polyamidoamine is added, stirring is carried out under nitrogen protection, and pretreatment waste liquid is obtained by desalination using bipolar membrane electrodialysis system;Pretreatment waste liquid is slowly added into prefabricated material, fully stirred, water is used to regulate system solid content, obtain environmentally friendly composite water-coal slurry additive. Raw material of the present invention is simple and easy to obtain, and process is simple, and has the characteristics that coal slurry concentration is high, fluidity and stability are all excellent simultaneously, existing naphthalene series water-coal slurry additive can be replaced, cost is reduced, and it is suitable for large-scale promotion and use.

Description

Technical Field

[0001] The present invention relates to the technical field of coal water slurry additives, and in particular to an environmentally friendly composite coal water slurry additive and a preparation method thereof. Background Art

[0002] Coal-water slurry is a coal-based fluid fuel and gasification raw material made from 60-65% coal, 40-35% water and about 0.1-0.2% additives through a certain processing technology. Its main utilization methods are combustion heat release and gasification synthesis of coal chemical raw materials.

[0003] Coal quality, coal powder particle size distribution, and additives are the three major factors affecting the preparation of coal-water slurry. Coal quality determines the slurrying effect of coal. Particle size distribution is the composition of particle sizes in the coal-water slurry product and is one of the key factors affecting slurrying. Grinding raw coal into coal-water slurry products requires a high stacking efficiency of the product particle size composition, with minimal stacking gaps. The gaps between large particles are filled with smaller particles, and the gaps between small particles are filled with even smaller particles. This reduces the amount of water in the gaps, increases the slurry concentration, and improves the fluidity of the coal slurry.

[0004] Additives are mainly used to improve the stability of coal slurry to facilitate long-distance transportation and storage. Since water-coal slurry is a coarse dispersion system of solid and liquid phases, coal particles can easily spontaneously agglomerate with each other and easily precipitate under the action of gravity or other external forces. In order to prevent precipitation or the formation of irreversible hard precipitates, additives are added to the water-coal slurry to make the coarse particle suspension of the water-coal slurry form a thixomorph. That is, the water-coal slurry becomes structured when it is left to stand and has high shear stress. When used, once an external force is applied, the viscosity can be rapidly reduced, and it has good fluidity. When left to stand again, it can restore its original structural state.

[0005] Among the properties of high-concentration coal-water slurries, low viscosity, good stability, and fluidity are the most important. However, coal is a hydrophobic material and a suspended particle. Even with easily slurried coal and a highly packed particle distribution, it is impossible to produce the desired high-concentration coal-water slurry without chemical additives. The main function of additives is to modify the surface properties of coal particles, promote particle dispersion in water, and impart good rheological properties and stability to the slurry.

[0006] Numerous additive manufacturers exist on the market, but product quality varies widely. While traditional naphthalene sulfonate additives can improve slurry performance, they suffer from significant drawbacks: First, they introduce excessive sulfate, leading to scaling in the slag-water system; second, the presence of chloride and phosphate ions increases the difficulty and environmental costs of wastewater treatment; and third, the synthesis process for naphthalene-based raw materials is complex and expensive. Furthermore, existing additives have limited adaptability to various coal types, making it difficult to achieve both low viscosity and long-term stability in high-concentration slurries. Therefore, the industry urgently needs to develop environmentally friendly, low-cost, and widely applicable alternative additives. Summary of the Invention

[0007] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an environmentally friendly composite water-coal slurry additive and a preparation method thereof.

[0008] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0009] S1. Add fatty alcohol polyoxyethylene ether to water, stir at a temperature of 40-50° C., add sodium gluconate, maintain the pH value of the system at 7-8, and stir to obtain a prefabricated material;

[0010] S2. Adjust the pH value of the papermaking waste liquid to 5-7, add an initiator and FeSO4·7H2O and mix evenly, perform microwave treatment at a microwave temperature of 60-80°C and a microwave power of 400-500W, add amino-terminated polyamidoamine, stir at a temperature of 40-50°C under nitrogen protection, increase the temperature to 70-80°C and continue stirring, and desalinate using a bipolar membrane electrodialysis system to obtain a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0011] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature to ≤50° C., fully stir, and use water to adjust the solid content of the system to 30-42% to obtain an environmentally friendly composite water-coal slurry additive.

[0012] Preferably, in S1, the weight ratio of fatty alcohol polyoxyethylene ether to sodium gluconate is 1-5:1.5-2.

[0013] Fatty alcohol polyoxyethylene ether is the most important type of nonionic surfactant. The ether bond in the molecule is not easily destroyed by acid or alkali, so it has high stability, good water solubility, good electrolyte resistance, easy biodegradation, and low foaming.

[0014] Fatty alcohol polyoxyethylene ether, general formula is RO(CH2CH2O) n H, where R is C 12 -C 18 A straight-chain or branched fatty alcohol group, n is the addition number of ethylene oxide (EO); preferably, the fatty alcohol polyoxyethylene ether is AEO-7 fatty alcohol polyoxyethylene ether.

[0015] Preferably, in S2, the weight ratio of papermaking waste liquid, amino-terminated polyamidoamine, initiator, and FeSO4·7H2O is 7-15:1-3:0.1-0.2:0.01-0.05.

[0016] Preferably, in S2, the papermaking waste liquor is sulfite chemical pulping waste liquor, wherein the concentration of sodium lignin sulfonate is 10-30 g / L, and the concentration of hemicellulose decomposition products is 20-40 g / L.

[0017] Preferably, in S2, the initiator is ammonium persulfate.

[0018] Preferably, in S2, the amino-terminated polyamidoamine has a generation number of 3.0.

[0019] Preferably, in S2, a bipolar membrane electrodialysis system is used for desalination, wherein the operating voltage is 3-5V and the current density is 10-15mA / cm 2 .

[0020] An environmentally friendly composite water-coal slurry additive is prepared by adopting the preparation method of the environmentally friendly composite water-coal slurry additive.

[0021] Beneficial effects:

[0022] In the present invention, an initiator is added to the papermaking waste liquid, and microwave-assisted cross-linking of lignin sulfonate and terminal amino polyamide amine is initiated to form a three-dimensional network structure. The terminal amino group is combined with oxygen-containing functional groups (such as carboxyl and hydroxyl groups) on the coal surface through electrostatic adsorption. At the same time, hyperbranched molecules are embedded in the cracks of coal particles, and lignin sulfonate wraps the particle surface to form a double stable layer. Even with high-concentration coal slurry, the low viscosity and long-term stability of the slurry can be guaranteed.

[0023] Fatty alcohol polyoxyethylene ether is a type of nonionic surfactant. The ether bonds in its molecules are not easily destroyed by acids or alkalis and have high stability. The present invention adopts sodium gluconate and fatty alcohol polyoxyethylene ether to compound, which not only reduces the entry of sulfate, chloride and phosphorus ions, but also effectively increases the adaptability of coal through the ratio of fatty alcohol polyoxyethylene ether and sodium gluconate in process control, and the coal has good slurrying performance.

[0024] Sodium gluconate can chelate Ca in coal 2+ Mg 2+ Plasma reduces hard precipitation; through hydrogen bonds and lignin sulfonate, it forms a three-dimensional network structure, giving the slurry thixotropy, cooperating with the pretreatment waste liquid to ensure high coal slurry concentration and significantly enhance the stability and fluidity of the system.

[0025] The invention reduces the entry of sulfate radicals, chloride ions and phosphorus ions, and at the same time fully utilizes papermaking waste liquid in the papermaking industry. The additive has adaptability to multiple types of coal and a wide range of uses. It can be widely used in the fields of raw material water-coal slurry and fuel water-coal slurry, and can be used to replace the water reducer commonly used in construction.

[0026] The raw materials of the present invention are simple and easy to obtain, the process is simple, easy to operate, and the requirements for production equipment are not high. The obtained water-coal slurry additive can significantly improve the performance of the coal slurry, has high coal slurry concentration, and is excellent in fluidity and stability. It can replace the existing naphthalene-based water-coal slurry additive, reduces costs, and is suitable for large-scale promotion and use. DETAILED DESCRIPTION

[0027] The present invention will be further explained below with reference to specific embodiments.

[0028] The following examples and comparative examples use Hengli Petrochemical Shenyou 2# coal as raw material. According to the particle size requirements of the provided coal slurry for gasification, coal powder of the required particle size is produced. The particle size distribution is closer to actual production. The particle size distribution of the experimental coal powder is shown in the following table:

[0029] Mesh range >14 14～40 40～200 200～325 <325 Proportion(%) 0.00 10.00 45.00 15.00 30.00

[0030] Example 1

[0031] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0032] S1. Add 1 part of fatty alcohol polyoxyethylene ether to 15 parts of water by weight, stir at a temperature of 40° C. for 20 min at a stirring speed of 200 r / min, add 1.5 parts of sodium gluconate, maintain the pH value of the system at 7, stir for 10 min at a stirring speed of 1000 r / min, and obtain a prefabricated material;

[0033] S2. Adjust the pH value of 7 parts of papermaking wastewater to 5, add 0.1 parts of ammonium persulfate and 0.01 parts of FeSO4·7H2O and mix them evenly. Microwave treatment is carried out for 10 minutes at a microwave temperature of 60°C and a microwave power of 400W. Add 1 part of 3.0 generation amino-terminated polyamidoamine and stir at 40°C for 10 minutes under nitrogen protection. Raise the temperature to 70°C and stir for 1 hour. Desalination is carried out using a bipolar membrane electrodialysis system, wherein the operating voltage is 3V and the current density is 10mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0034] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 10 g / L and the concentration of hemicellulose decomposition products is 20 g / L;

[0035] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤ 50° C., fully stir for 30 minutes at a stirring speed of 800 r / min, and use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0036] To test the performance of the coal water slurry additive, Hengli Petrochemical Shenyou 2# coal was used as raw material and slurried after drying at a temperature of 120°C. The highest slurry concentration reached 62.47%, and no hard precipitate was produced after 15 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis) mass. The coal water slurry additive of this embodiment not only has excellent dispersibility, but also has good stability.

[0037] Example 2

[0038] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0039] S1. Add 5 parts of fatty alcohol polyoxyethylene ether by weight to 30 parts of water, stir at a temperature of 50° C. for 30 min at a stirring speed of 400 r / min, add 2 parts of sodium gluconate, maintain the pH value of the system at 8, stir for 30 min at a stirring speed of 1500 r / min, and obtain a prefabricated material;

[0040] S2. Adjust the pH value of 15 parts of papermaking wastewater to 6.9, add 0.2 parts of ammonium persulfate and 0.05 parts of FeSO4·7H2O and mix them evenly. Microwave treatment is carried out for 20 minutes at a microwave temperature of 80°C and a microwave power of 500W. Add 3 parts of 3.0 generation amino-terminated polyamidoamine and stir at 50°C for 20 minutes under nitrogen protection. Raise the temperature to 80°C and stir for 2 hours. Desalination is carried out using a bipolar membrane electrodialysis system, wherein the operating voltage is 5V and the current density is 15mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0041] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 30 g / L and the concentration of hemicellulose decomposition products is 40 g / L;

[0042] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤50°C, fully stir for 40 minutes, and stir at a speed of 1200r / min. Use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0043] To test the performance of the coal-water slurry additive, Hengli Petrochemical Shenyou 2# coal was used as raw material and slurried after drying at 120°C. The highest slurry concentration reached 62.51%, and no hard precipitate was produced after 15 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis) mass. The coal-water slurry additive of this embodiment not only has excellent dispersibility, but also has good stability.

[0044] Example 3

[0045] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0046] S1. Add 2 parts of fatty alcohol polyoxyethylene ether by weight to 18 parts of water, stir at a temperature of 42 ° C for 22 minutes, and stir at a speed of 250 r / min, add 1.6 parts of sodium gluconate, maintain the pH value of the system at 7.2, and stir for 12 minutes at a stirring speed of 1200 r / min to obtain a prefabricated material;

[0047] S2. Adjust the pH value of 8 parts of papermaking waste liquid to 5.5, add 0.12 parts of ammonium persulfate and 0.02 parts of FeSO4·7H2O and mix them evenly. Microwave treatment is carried out for 12 minutes at a microwave temperature of 65°C and a microwave power of 420W. Add 1.5 parts of 3.0-generation amino-terminated polyamidoamine and stir at 41°C for 12 minutes under nitrogen protection. Raise the temperature to 72°C and stir for 1.2 hours. Desalination is carried out using a bipolar membrane electrodialysis system, wherein the operating voltage is 3.5V and the current density is 12mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0048] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 15 g / L and the concentration of hemicellulose decomposition products is 25 g / L;

[0049] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤50°C, fully stir for 32 minutes, and stir at a speed of 900r / min. Use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0050] To test the performance of the coal water slurry additive, Hengli Petrochemical Shenyou 2# coal was used as raw material and slurried after drying at a temperature of 120°C. The maximum slurry concentration reached 62.53%, and no hard precipitate was produced after 15 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis) mass. The coal water slurry additive of this embodiment not only has excellent dispersibility, but also has good stability.

[0051] Example 4

[0052] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0053] S1. Add 3 parts of fatty alcohol polyoxyethylene ether by weight to 28 parts of water, stir at a temperature of 48 ° C for 25 minutes, and stir at a speed of 300 r / min. Add 1.8 parts of sodium gluconate, maintain the pH value of the system at 7.5, and stir for 25 minutes at a stirring speed of 1400 r / min to obtain a prefabricated material;

[0054] S2. Adjust the pH value of 12 parts of papermaking waste liquid to 6.8, add 0.18 parts of ammonium persulfate and 0.04 parts of FeSO4·7H2O and mix them evenly. Microwave treatment is carried out for 15 minutes at a microwave temperature of 78°C and a microwave power of 480W. Add 2.5 parts of 3.0-generation amino-terminated polyamidoamine and stir at 48°C for 18 minutes under nitrogen protection. Raise the temperature to 78°C and stir for 1.5 hours. Desalination is carried out using a bipolar membrane electrodialysis system, wherein the operating voltage is 4.5V and the current density is 14mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0055] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 26 g / L and the concentration of hemicellulose decomposition products is 38 g / L;

[0056] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤50°C, fully stir for 38 minutes, and stir at a speed of 1100r / min. Use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0057] To test the performance of the coal-water slurry additive, Hengli Petrochemical Shenyou 2# coal was used as raw material and slurried after drying at 120°C. The highest slurry concentration reached 62.52%, and no hard precipitate was produced after 15 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis). The coal-water slurry additive of this embodiment not only has excellent dispersibility, but also has good stability.

[0058] Example 5

[0059] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0060] S1. Add 2 parts of fatty alcohol polyoxyethylene ether by weight to 25 parts of water, stir at a temperature of 45 ° C for 25 minutes, and stir at a speed of 300 r / min. Add 1.8 parts of sodium gluconate, maintain the pH value of the system at 7.6, and stir for 18 minutes at a stirring speed of 1200 r / min to obtain a prefabricated material;

[0061] S2. Adjust the pH value of 10 parts of papermaking wastewater to 6, add 0.15 parts of ammonium persulfate and 0.03 parts of FeSO4·7H2O and mix them evenly. Microwave treatment is carried out for 15 minutes at a microwave temperature of 70°C and a microwave power of 450W. Add 2 parts of 3.0-generation amino-terminated polyamidoamine and stir at 45°C for 15 minutes under nitrogen protection. Raise the temperature to 75°C and stir for 1.5 hours. Desalination is carried out using a bipolar membrane electrodialysis system, wherein the operating voltage is 4V and the current density is 15mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0062] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 20 g / L and the concentration of hemicellulose decomposition products is 30 g / L;

[0063] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤ 50° C., fully stir for 35 minutes, and stir at a speed of 1000 r / min. Use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0064] To test the performance of the coal-water slurry additive, Hengli Petrochemical Shenyou 2# coal was used as raw material and slurried after drying at 120°C. The highest slurry concentration reached 62.51%, and no hard precipitate was produced after 15 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis) mass. The coal-water slurry additive of this embodiment not only has excellent dispersibility, but also has good stability.

[0065] Comparative Example 1

[0066] Naphthalene-based additives produced by Laiwu Shuangquan Building Materials Co., Ltd. were used, and Hengli Petrochemical Shenyou 2# coal was used as raw material. After drying at a temperature of 120°C, the pulping was carried out. The highest pulping concentration was 62.43%, and hard precipitates were produced in 13 days. The amount of additives used (converted to solid) was 2.35% of the mass of the coal (dry basis).

[0067] Comparative Example 2

[0068] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0069] S1. Add 2 parts of fatty alcohol polyoxyethylene ether by weight to 25 parts of water, stir at a temperature of 45 ° C for 25 minutes, and stir at a speed of 300 r / min. Add 1.8 parts of sodium gluconate, maintain the pH value of the system at 7.6, and stir for 18 minutes at a stirring speed of 1200 r / min to obtain a prefabricated material;

[0070] S2. Adjust the pH value of 10 parts of papermaking wastewater to 6, then add 2 parts of 3.0 generation amino-terminated polyamidoamine and mix well. Use bipolar membrane electrodialysis system for desalination, where the operating voltage is 4V and the current density is 15mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0071] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 20 g / L and the concentration of hemicellulose decomposition products is 30 g / L;

[0072] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤ 50° C., fully stir for 35 minutes, and stir at a speed of 1000 r / min. Use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0073] Using Hengli Petrochemical Shenyou 2# coal as raw material, the pulp was dried at 120°C and then slurried. The maximum pulping concentration was 60.65%, and a hard precipitate formed after 10 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis) mass.

[0074] Comparative Example 3

[0075] A method for preparing an environmentally friendly composite coal water slurry additive comprises the following steps:

[0076] S1. Add 2 parts of fatty alcohol polyoxyethylene ether by weight to 25 parts of water, stir at a temperature of 45 ° C for 25 minutes, and stir at a speed of 300 r / min. Add 1.8 parts of sodium gluconate, maintain the pH value of the system at 7.6, and stir for 18 minutes at a stirring speed of 1200 r / min to obtain a prefabricated material;

[0077] S2. Adjust the pH value of 10 parts of papermaking wastewater to 6, add 0.15 parts of ammonium persulfate and 0.03 parts of FeSO4·7H2O and mix them evenly. Microwave treatment is carried out for 15 minutes at a microwave temperature of 70°C and a microwave power of 450W. Desalination is carried out using a bipolar membrane electrodialysis system, with an operating voltage of 4V and a current density of 15mA / cm 2 , obtaining a pretreated waste liquid with a conductivity of ≤500 μS / cm;

[0078] The papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 20 g / L and the concentration of hemicellulose decomposition products is 30 g / L;

[0079] S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature ≤50°C, fully stir for 35 minutes, and stir at a speed of 1000r / min. Add 2 parts of 3.0-generation amino-terminated polyamidoamine, and use water to adjust the solid content of the system to 42% to obtain an environmentally friendly composite water-coal slurry additive.

[0080] Using Hengli Petrochemical Shenyou 2# coal as raw material, the pulp was dried at 120°C and then slurried. The maximum pulping concentration was 59.32%, and hard precipitates formed after 10 days. The additive dosage (solid basis) was 2.35% of the coal (dry basis) mass.

[0081] The water-coal slurry additives of Example 5 and Comparative Examples 1-3 were tested with the additive dosage (solid basis) being 2.35% of the mass of coal (dry basis).

[0082] The concentration of coal slurry was determined with reference to GB / T 18856.2-2008 “Test methods for coal-water slurries - Part 2: Determination of concentration”; the viscosity of coal slurry was determined with reference to GB / T 18856.2-2008 “Test methods for coal-water slurries - Part 4: Determination of apparent viscosity”.

[0083] The fluidity of coal slurry is determined by visual inspection, and the coal slurry is divided into three grades: A (continuous flow), B (intermittent flow), and C (almost no flow or no flow); Grade A is a thin fluid, which flows continuously, smoothly and uninterruptedly; Grade B is a thick fluid, which flows relatively continuously but has an uneven surface; Grade C is a fluid that can only flow well with the help of external force or is muddy and cannot flow; "+" indicates better fluidity in a certain grade; "-" indicates poorer fluidity in a certain grade.

[0084] The water extraction rate was determined with reference to GB / T18856.5-2008 "Test methods for coal-water slurry - Part 5: Determination of stability", as follows: the sample was poured into a 100 mL graduated cylinder, allowed to stand for 24 hours, and then the scale value was read to determine the water extraction rate.

[0085] The content of sodium sulfate and chloride ion was determined with reference to GB / T 8077-2012 "Test method for homogeneity of concrete admixtures".

[0086] The performance test results are shown in Table 1.

[0087] Table 1 Performance test results of coal water slurry additives obtained in Example 5 and Comparative Examples 1-3

[0088]

[0089] As can be seen from the above table, the environmentally friendly water-coal slurry additive obtained in Example 5 of the present invention has achieved similar effects as the common naphthalene additives on the market through laboratory simulation tests, but has reduced environmental pressure and is suitable for large-scale promotion and use.

[0090] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an environmentally friendly composite coal water slurry additive, characterized in that: The steps include: S1. Add fatty alcohol polyoxyethylene ether to water, stir at a temperature of 40-50° C., add sodium gluconate, maintain the pH value of the system at 7-8, and stir to obtain a prefabricated material; S2. Adjust the pH value of the papermaking waste liquid to 5-7, add an initiator and FeSO4·7H2O and mix evenly, perform microwave treatment at a microwave temperature of 60-80°C and a microwave power of 400-500W, add amino-terminated polyamidoamine, stir at a temperature of 40-50°C under nitrogen protection, increase the temperature to 70-80°C and continue stirring, and desalinate using a bipolar membrane electrodialysis system to obtain a pretreated waste liquid with a conductivity of ≤500 μS / cm; In S2, the papermaking waste liquid is sulfite chemical pulping waste liquid, wherein the concentration of sodium lignin sulfonate is 10-30 g / L, and the concentration of hemicellulose decomposition products is 20-40 g / L; S3. Slowly add the pretreated waste liquid to the prefabricated material, control the temperature to ≤50°C, stir thoroughly, and use water to adjust the solid content of the system to 30-42% to obtain an environmentally friendly composite water-coal slurry additive.

2. The method for preparing the environmentally friendly composite coal water slurry additive according to claim 1, characterized in that: In S1, the weight ratio of fatty alcohol polyoxyethylene ether to sodium gluconate is 1-5:1.5-2.

3. The method for preparing the environmentally friendly composite coal water slurry additive according to claim 1, characterized in that: In S2, the weight ratio of papermaking waste liquid, amino-terminated polyamidoamine, initiator, and FeSO4•7H2O is 7-15:1-3:0.1-0.2:0.01-0.

05.

4. The method for preparing the environmentally friendly composite coal water slurry additive according to claim 1, characterized in that: In S2, the initiator is ammonium persulfate.

5. The method for preparing the environmentally friendly composite coal water slurry additive according to claim 1, characterized in that: In S2, the amino-terminated polyamidoamine has a generation number of 3.

0.

6. The method for preparing the environmentally friendly composite coal water slurry additive according to claim 1, characterized in that: In S2, a bipolar membrane electrodialysis system is used for desalination, with an operating voltage of 3-5V and a current density of 10-15mA / cm².

7. An environmentally friendly composite coal water slurry additive, characterized in that: The environmentally friendly composite water-coal slurry additive is prepared by the preparation method of any one of claims 1 to 6.

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