Dispersing scale inhibitor and preparation method thereof

Abstract

The invention relates to a dispersing scale inhibitor and a preparation method thereof, and relates to the technical field of water treatment.The dispersing scale inhibitor is prepared from, by mass, 25%-45% of polycarboxylic acid compounds, 15%-25% of organic phosphine compounds, 0.3%-0.8% of surfactants, 1%-3% of sodium tungstate, 2%-5% of polyepichlorohydrin dimethylamine, 0.5%-2% of epsilon-polylysine, 1%-3% of trehalose and the balance water. The dispersing scale inhibitor disclosed by the invention has excellent scale inhibition efficiency, excellent dispersing performance, wide scale adaptability and good high-temperature stability.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a scale inhibitor and its preparation method. Background Technology

[0002] With the rapid development of industries such as coal chemical, oil and gas extraction, seawater desalination, and fine chemicals, the discharge of high-salinity wastewater has increased dramatically, with total dissolved solids (TDS) often exceeding 10,000 mg / L, and even reaching saturation. Direct discharge of such wastewater poses a serious threat to aquatic ecosystems and soil environments. Therefore, achieving resource recovery and "zero discharge" of high-salinity wastewater has become a mandatory requirement for industrial sustainable development and environmental regulations. In mainstream "zero discharge" processes, membrane concentration (such as reverse osmosis and nanofiltration) and evaporation crystallization are the core units for achieving water recovery and salt solidification. However, during this process, dissolved salts are highly concentrated, easily exceeding their solubility product constant and precipitating out, forming a dense scale layer on the membrane surface and evaporator heat exchange walls. This leads to a series of problems such as membrane flux decline, increased system operating pressure, and a significant decrease in heat transfer efficiency, severely restricting the stability and economy of the entire treatment process.

[0003] Adding scale inhibitors is the most economical and effective technical means to alleviate the above-mentioned scaling problems. Its mechanism of action is mainly based on threshold effect, lattice distortion and dispersion effect. However, conventional scale inhibitors face severe challenges in dealing with extreme working conditions of high salt, high hardness and high temperature: (1) High concentrations of background electrolytes (such as Na⁺, Cl⁻) will produce a strong "salt effect", which will shield the electrostatic interaction between the functional groups of the scale inhibitor and the scale-forming ions (such as Ca²⁺, Ba²⁺, Sr²⁺), resulting in a significant weakening of its threshold effect; (2) Traditional polycarboxylic acid scale inhibitors are prone to cross-linking reaction with high-valence metal ions, forming insoluble flocs or precipitates, which not only lose the scale inhibition function, but may also become a new source of fouling; (3) In a high ionic strength environment, the double electric layer of colloidal particles is strongly compressed, which makes the dispersion system maintained by electrostatic repulsion unstable, resulting in rapid aggregation and deposition of microcrystals.

[0004] Chinese invention patent CN105502703A discloses a compounded high-efficiency scale inhibitor, comprising the following components by weight: 15-25 parts initiator, 10-15 parts monomer raw material, 20-30 parts compounding agent, 15-20 parts solvent, and 30-50 parts additives; wherein the initiator is a mixture of sodium bisulfite and ammonium persulfate, the monomer raw material is a mixture of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, the compounding agent is 2-phosphonobutane-1,2,4-tricarboxylic acid, the solvent is deionized water, and the additives are a mixture of epoxy resin, amino resin, rust inhibitor, and corrosion inhibitor. By introducing sulfonic acid monomers such as 2-acrylamide-2-methylpropanesulfonic acid and copolymerizing them with carboxylic acid monomers (such as acrylic acid) and nonionic monomers, the excellent hydration capacity and anti-ionic interference properties of the sulfonic acid groups are utilized to improve the calcium tolerance and dispersibility of the polymer. Although the above scale inhibitors have achieved good scale inhibition effects, their inherent defects are still very prominent: (1) The conformational stability of the polymer molecular chain is poor, and it is easy to curl under high ionic strength, which weakens its steric hindrance effect and leads to a decrease in the ability to disperse submicron-sized crystal nuclei; (2) The single polymer molecular structure is difficult to produce the best synergistic inhibition effect on multiple scale types such as silica scale, iron scale, calcium scale, and barium scale under complex and variable water quality conditions; (3) In the high temperature (>100°C) environment during the evaporation and crystallization stage, the polymer chain may be hydrolyzed or thermally degraded, resulting in poor long-term stability.

[0005] Therefore, developing a scale inhibitor with excellent scale inhibition efficiency, superior dispersion performance, broad scale adaptability, and good high-temperature stability is an urgent technical need. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a dispersing scale inhibitor and its preparation method. The dispersing scale inhibitor of this invention exhibits excellent scale inhibition efficiency, superior dispersion performance, broad adaptability to various scale types, and good high-temperature stability.

[0007] In a first aspect, the present invention provides a scale inhibitor comprising, by mass percentage, 25-45% polycarboxylic acid compounds, 15-25% organophosphorus compounds, 0.3-0.8% surfactant, 1-3% sodium tungstate, 2-5% polyepoxychloropropane dimethylamine, 0.5-2% ε-polylysine, 1-3% trehalose, with the balance being water.

[0008] In the above technical solution, polycarboxylic acid compounds and organophosphorus compounds are the main components. Polycarboxylic acid compounds mainly provide steric hindrance and lattice distortion effects, responsible for dispersing microcrystalline particles. Organophosphorus compounds mainly provide chelation and threshold effects, directly inhibiting scale nucleation and growth. Through the compounding of polycarboxylic acid polymers and organophosphorus compounds, complementary mechanisms and synergistic effects are achieved, which can significantly improve the inhibition efficiency of common scales such as calcium sulfate and calcium carbonate, as well as sparingly soluble scales such as barium sulfate and strontium sulfate with extremely low solubility. The optimized ratio of polymer functional groups and molecular weight distribution, combined with the stabilizing effect of organophosphorus compounds, enable the dispersant scale inhibitor to effectively maintain the molecular chain conformation under high ionic strength environment, providing stronger steric hindrance and electrostatic stabilization effects. Moreover, the selected polycarboxylic acid compounds and organophosphorus compounds have good stability, giving the dispersant scale inhibitor good high-temperature resistance, allowing it to maintain long-term chemical stability and scale inhibition activity under high-temperature process conditions such as evaporation and crystallization, with a low performance degradation rate.

[0009] Surfactants can reduce the surface tension of chemical solutions and wastewater, making them easier to spread and penetrate on membrane surfaces, heat exchanger tube walls, or existing soft scale. This allows the main scale inhibitors to reach their target sites more effectively and also helps to remove loose scale and slime that have already formed.

[0010] tungstate ions (WO4) in sodium tungstate 2- The metal will migrate to the anodic region of the metal equipment, promoting the formation of a dense passivation film on its surface. The main components of the passivation film are Fe2O3 and tungsten oxides. This film can greatly prevent further corrosion of the metal.

[0011] Polyepoxychloropropane dimethylamine, as a cationic polymer, effectively neutralizes the charge of negatively charged organic colloids, humic acids, and suspended particulate matter in water through its high positive charge density. It also aggregates these substances into larger, more easily settled or filtered flocs through adsorption bridging. Furthermore, it can address organic colloidal fouling that anionic scale inhibitors cannot handle, preventing these colloids from becoming scale binders or directly causing blockages.

[0012] Free Fe in water 3+ Al 3+ Cu 2+ High-valence metal ions readily form insoluble gels or precipitates with polycarboxylic acid compounds and organophosphonic acid compounds, leading to the inactivation of the main agent. The amino groups (-NH2) abundant on the ε-polylysine molecular chain preferentially react with free Fe in water. 3+ Al 3+ Cu 2+ High-valence metal ions undergo strong integration, preventing the formation of insoluble gels and precipitates. Simultaneously, as a natural antibacterial agent, ε-polylysine inhibits bacterial growth in the system and prevents the formation of biofilm.

[0013] Trehalose molecules possess extremely strong hydrogen bonding capabilities. Under stressful environments such as high salt and high temperature, they can partially encapsulate polymer and organophosphonic acid molecules through hydrogen bonds, forming a protective hydration layer. This layer can slow down polymer chain breakage at high temperatures and the chemical degradation of organophosphonic acid molecules. It also helps polycarboxylic acid molecules resist chain coiling under high ionic strength, maintaining an extended conformation and thus preserving their steric hindrance effectiveness.

[0014] Optionally, the polycarboxylic acid compound is any one or more of polyacrylic acid, polyepoxysuccinic acid, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and carboxylate-sulfonate-acrylate; preferably, the polycarboxylic acid compound is carboxylate-sulfonate-acrylate.

[0015] In the above technical solution, the carboxyl group (-COO) on the molecular chain of the polycarboxylic acid compound - These substances can adsorb onto the active growth sites of microcrystals, interfering with the ordered arrangement of the crystal lattice, causing crystal distortion, making them loose and easily washed away by water. The long polymer chains extend in water, forming a dynamic barrier. When microcrystals form, these long chains physically prevent them from approaching each other and agglomerating, keeping them dispersed. Ionized carboxyl and sulfonic acid groups (such as the -SO3 groups in carboxylate-sulfonate-acrylate) can also contribute to this effect. - This makes the polymer chains negatively charged, which electrostatically repels the equally negatively charged colloidal particles and microcrystals, preventing their deposition.

[0016] Optionally, the organophosphorus compound is any one or more of diethylenetriaminepentamethylenephosphonic acid, heptasodium diethylenetriaminepentamethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, polyaminopolyether methylenephosphonic acid, and bis(1,6-hexyltriaminepentamethylenephosphonic acid); preferably, the organophosphorus compound is any one or two of polyaminopolyether methylenephosphonic acid and bis(1,6-hexyltriaminepentamethylenephosphonic acid).

[0017] In the above technical solution, organophosphonic acid molecules in organophosphorus compounds can be adsorbed onto the surface of the crystal nucleus, inhibiting its continued growth. Furthermore, the phosphonic acid group (-PO3H2) has a positive effect on Ca... 2+ Mg 2+ Ba 2+ 、Sr 2+ High-valence metal ions have a strong complexing ability, which can reduce the concentration of free ions, thus making it difficult for them to form scale.

[0018] Optionally, the surfactant is a nonionic surfactant or an amphoteric surfactant; the nonionic surfactant is an alkylphenol polyoxyethylene ether or a fatty alcohol polyoxyethylene ether, and the amphoteric surfactant is cocamidopropyl betaine or sulfobetaine.

[0019] In the above technical solution, the nonionic surfactant of this application has the advantages of resistance to high concentrations of acids and alkalis, hard water, and oxidants. It is very stable in environments with high salt content and where oxidizing bactericides such as chlorine may be present. Furthermore, it has good spreading and penetrating ability on organic scale and metal surfaces, helping the effective components of the scale inhibitor to penetrate into the scale layer.

[0020] The zwitterionic surfactant of this application carries both positive and negative charges, exhibiting good compatibility with anionic, cationic, and nonionic substances, thus avoiding charge conflicts when compounded with polycarboxylic acid (anionic) and polyepoxychloropropane dimethylamine (cationic). The zwitterionic molecules can form a dense, highly hydrated protective layer on the membrane surface or metal equipment surface through strong electric dipole interactions. This hydrated layer physically repels the approach and adhesion of contaminants such as inorganic microcrystals, organic colloids, and biomolecules. It is also typically low in irritation and exhibits good biodegradability. Furthermore, it maintains stable performance over a wide pH range.

[0021] Optionally, the scale inhibitor further includes a water structure modifier comprising 0.5%-1% by mass, wherein the water structure modifier is tetrabutylammonium bromide.

[0022] In the above technical solution, water molecules form dynamic clusters of varying sizes through hydrogen bonds. The quaternary ammonium cation in tetrabutylammonium bromide ([N(C4H9)4)) + Calcium carbonate (CFC) is hydrophobic. When it enters water, to minimize the disruption of the hydrogen bond network caused by its hydrophobic surface, water molecules rearrange themselves around it, forming a more ordered and rigid structure, thus disrupting the hydrogen bond network of water molecules. Scale-forming ions (such as Ca²⁺) can also contribute to this. 2+ SO4 2- In water, these molecules are also surrounded by a hydration shell. To form crystals, they must partially shed this hydration shell to approach each other. When tetrabutylammonium bromide disrupts the hydrogen bond network of bulk water, the interaction (ion-dipole interaction) between water molecules and scale-forming ions is relatively enhanced. This indicates that ions require higher energy to escape their hydration shell, which increases the solubility of scale-forming substances, thereby delaying the formation and growth of crystal nuclei and thus increasing the solvation energy of scale-forming ions.

[0023] Secondly, the present invention provides a method for preparing a dispersing scale inhibitor, the method comprising the following steps: At room temperature and a rotation speed of 200-300 rpm, a polycarboxylic acid compound is slowly added to water and stirred continuously for 20-30 minutes until the polymer is completely dissolved. While continuing to stir, trehalose and ε-polylysine are added sequentially, and stirring is continued for 20-30 minutes until the mixture is homogeneous. The rotation speed is increased to 300-400 rpm and the temperature is 25-40°C. An organophosphorus compound is slowly added dropwise, and stirring is continued for 15-20 minutes. Under this condition, sodium tungstate and a surfactant are added sequentially, and stirring is continued for 10-20 minutes. Finally, a polyepoxychloropropane dimethylamine solution diluted with water is slowly added dropwise at 400-500 rpm and 30-40°C, and stirring is continued for 20-30 minutes. The pH is adjusted to 7.5-8.0 to obtain the dispersing scale inhibitor.

[0024] In the above technical solution, the polycarboxylic acid compound molecular chains need to extend and hydrate in water to form a uniform dispersion system. Therefore, the complete dissolution process of the polymer plays an important role in the subsequent steric hindrance effect. Trehalose and ε-polylysine are mixed with the polymer solution first because ε-polylysine can integrate trace amounts of high-valence metal ions that may be present in the water in advance, while trehalose interacts with the polymer molecules through hydrogen bonds, establishing a protective environment in advance to prepare for subsequent high temperature or chemical stress. Organophosphonic acid compounds are usually acidic and highly concentrated; rapid addition in large quantities can lead to local overheating and a sudden drop in pH, easily causing the polycarboxylic acid molecular chains to curl or even precipitate. Slow dropwise addition ensures a stable and gentle mixing of the system. Under mild conditions, organophosphonic acid compounds and polycarboxylic acid polymers can form a synergistic composite structure in advance through calcium ion "bridging" or direct weak intermolecular forces, rather than simple physical mixing. Adding sodium tungstate first, followed by the surfactant, avoids salting out and aggregation phenomena that may occur when the surfactant encounters high-concentration electrolytes, ensuring uniform dispersion. Polyepoxychloropropane dimethylamine carries a strong positive charge, while polycarboxylic acid polymers carry a strong negative charge. Direct and rapid mixing will instantly produce a strong charge neutralization effect, forming an insoluble macromolecular complex precipitate. Diluting the polyepoxychloropropane dimethylamine first, and then slowly adding it dropwise under high-speed stirring, allows the cationic polymer to be rapidly dispersed throughout the system upon contact with the anionic polymer, ensuring it only acts on tiny colloidal particles rather than reacting macroscopically with the main scale inhibitor. Adjusting the pH to neutral or slightly alkaline is equipment-friendly and maintains the chemical stability of each component. Too low a pH will exacerbate equipment corrosion and may destabilize some components; too high a pH may promote the premature formation of hydroxide precipitates from calcium and magnesium ions.

[0025] Optionally, the preparation method further includes adding trehalose and ε-polylysine sequentially while stirring, stirring for 20-30 minutes until the mixture is homogeneous, then adding a water structure modifier and stirring for 15-20 minutes until the mixture is homogeneous.

[0026] In the above technical solution, the water structure modifier is added early, which can provide it with sufficient time and a homogeneous environment to fully interact with water molecules and destroy the original hydrogen bond network. Thus, when scale-forming ions are added later, a solvent environment that can inhibit scale formation is already prepared.

[0027] The polycarboxylic acid polymers have been fully hydrated and stretched, forming a stable dispersion system. When a water structure modifier is added at this point, its cationic nature encounters the anionic polymer. However, because it is in a stable system and the concentration is very low, it is insufficient to initiate flocculation. Instead, it can begin to play a role under mild conditions.

[0028] Organophosphonic acids are highly acidic and concentrated components; their addition can cause drastic changes in the pH and ionic strength of the system. Uniformly dispersing the water structure modifier before these changes occur can prevent a series of reactions from taking place.

[0029] By allowing a greater time interval between the addition of the water structure modifier and the addition of polyepoxychloropropane dimethylamine, the instability of the system caused by the synergistic effect of the two positively charged substances can be minimized.

[0030] Thirdly, the present invention provides a dispersing scale inhibitor prepared by a dispersing scale inhibitor preparation process, or the application of a dispersing scale inhibitor in high-salt wastewater generated in the coal chemical industry, oil and gas extraction industry, seawater desalination industry, and fine chemical industry.

[0031] In summary, the present invention has at least one of the following beneficial technical effects: 1. By adding polycarboxylic acid compounds and organophosphorus compounds, the combination of the two achieves complementary mechanisms and synergistic effects, which can significantly improve the high temperature resistance of the dispersant and scale inhibitor, enabling it to maintain long-term chemical stability and scale inhibition activity under high temperature process conditions such as evaporation and crystallization.

[0032] 2. By adding surfactants, the surface tension of the solution and wastewater can be reduced, making it easier for them to spread and penetrate on the membrane surface, heat exchange tube wall or existing soft scale. This allows the main scale inhibitor to reach the action site more effectively and also helps to remove the loose scale layer and slime that has already formed.

[0033] 3. By adding polyepoxychloropropane dimethylamine, its high positive charge density can effectively neutralize the charge of negatively charged organic colloids, humic acid, and suspended particulate matter in the water. Through adsorption and bridging, it can coagulate them into larger flocs that are easy to settle or filter. It can also address organic colloidal fouling that anionic scale inhibitors cannot handle, preventing these organic colloids from becoming scale binders or directly causing blockages.

[0034] 4. By adding water structure modifiers, the cluster structure of water molecules can be disrupted, the water turbulence can be increased, the solubility of scale-forming ions can be improved, the solubility of scale can be increased, and nucleation can be delayed. Attached Figure Description

[0035] Figure 1 These are diagrams illustrating the scale inhibition effect of calcium sulfate in high-salt wastewater in the embodiments, comparative examples, and blank controls of this application. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments.

[0037] All materials used in the following examples are available for purchase on the market.

[0038] Example 1: A scale inhibitor and its preparation method.

[0039] The scale inhibitor comprises, by mass percentage, 25% polyacrylic acid, 10% polyepoxysuccinic acid, 15% sodium diethylenetriamine pentamethylphosphonate, 0.3% alkylphenol polyoxyethylene ether, 1% sodium tungstate, 2% polyepoxychloropropane dimethylamine, 0.5% ε-polylysine, 1% trehalose, with the balance being water, for a total of 100%.

[0040] The preparation method includes the following steps: S1. At room temperature and a stirring speed of 250 rpm, slowly add polyacrylic acid and polyepoxysuccinic acid to water and stir continuously for 25 min until the polymer is completely dissolved to obtain solution A. S2. Continue to add trehalose and ε-polylysine to solution A while stirring, and continue stirring for 25 minutes until the mixture is homogeneous to obtain solution B. S3. Increase the rotation speed to 350 rpm and the temperature to 35℃. Slowly add sodium diethylenetriaminepentamethylphosphonate heptasodium to solution B and stir for 20 min to obtain solution C. S4. Under this condition, sodium tungstate and alkylphenol polyoxyethylene ether are added to solution C in sequence, and stirring is continued for 15 minutes to obtain solution D. S5. Finally, at 450 rpm and 35°C, a polyepoxychloropropane dimethylamine solution diluted with water is slowly added dropwise to solution D. The mixture is stirred continuously for 25 min, and the pH is adjusted to 7.5-8.0 to obtain the scale inhibitor #1.

[0041] Example 2: A scale inhibitor and its preparation method.

[0042] The dispersant and scale inhibitor comprises, by mass percentage, 45% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 15% diethylenetriamine pentamethylphosphonic acid, 10% 2-phosphonobutane-1,2,4-tricarboxylic acid, 0.8% cocamidopropyl betaine, 3% sodium tungstate, 5% polyepoxychloropropane dimethylamine, 2% ε-polylysine, 3% trehalose, with the balance being water, for a total of 100%.

[0043] The preparation method is the same as in Example 1.

[0044] Example 3: A scale inhibitor and its preparation method.

[0045] The scale inhibitor comprises, by mass percentage, 20% polyacrylic acid, 25% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 10% diethylenetriamine pentamethylphosphonic acid, 10% bis(1,6-hexyltriamine pentamethylphosphonic acid), 0.5% fatty alcohol polyoxyethylene ether, 2% sodium tungstate, 3% polyepoxychloropropane dimethylamine, 1% ε-polylysine, 2% trehalose, with the balance being water, for a total of 100%.

[0046] The preparation method is the same as in Example 1.

[0047] Example 4: A scale inhibitor and its preparation method.

[0048] The scale inhibitor comprises, by mass percentage, 20% carboxylate-sulfonate-acrylate, 10% polyepoxysuccinic acid, 20% polyamino-polyether methylenephosphonic acid, 0.6% sulfobetaine, 1.5% sodium tungstate, 3% polyepoxychloropropane dimethylamine, 1.5% ε-polylysine, 1.5% trehalose, with the balance being water, for a total of 100%.

[0049] The preparation method is the same as in Example 1.

[0050] Example 5: A scale inhibitor and its preparation method.

[0051] The scale inhibitor comprises, by mass percentage, 30% carboxylate-sulfonate-acrylate, 5% diethylenetriamine pentamethylphosphonic acid, 20% 2-phosphonobutane-1,2,4-tricarboxylic acid, 0.4% alkylphenol polyoxyethylene ether, 2% sodium tungstate, 4% polyepoxychloropropane dimethylamine, 1.2% ε-polylysine, 2% trehalose, with the balance being water, for a total of 100%.

[0052] The preparation method is the same as in Example 1.

[0053] Example 6: A scale inhibitor and its preparation method.

[0054] The scale inhibitor comprises, by mass percentage, 30% carboxylate-sulfonate-acrylate, 25% polyamino-polyether methylenephosphonic acid, 0.5% fatty alcohol polyoxyethylene ether, 2% sodium tungstate, 3.5% polyepoxychloropropane dimethylamine, 1% ε-polylysine, 2% trehalose, and the balance being water, for a total of 100%.

[0055] The preparation method is the same as in Example 1.

[0056] Example 7: A scale inhibitor and its preparation method.

[0057] The scale inhibitor comprises, by mass percentage, 40% carboxylate-sulfonate-acrylate, 20% bis(1,6-hexyltriaminepentamethylphosphonic acid), 0.6% cocamidopropyl betaine, 2% sodium tungstate, 3% polyepichlorohydrin dimethylamine, 1.5% ε-polylysine, 2% trehalose, with the balance being water, for a total of 100%.

[0058] The preparation method is the same as in Example 1.

[0059] Example 8: A scale inhibitor and its preparation method.

[0060] The scale inhibitor comprises, by mass percentage, 35% carboxylate-sulfonate-acrylate, 15% polyamino-polyether methylenephosphonic acid, 20% bis(1,6-hexyltriamine)pentamethylenephosphonic acid, 0.5% fatty alcohol polyoxyethylene ether, 2% sodium tungstate, 3.5% polyepoxychloropropane dimethylamine, 1.5% ε-polylysine, 2% trehalose, with the balance being water, for a total of 100%.

[0061] The preparation method is the same as in Example 1.

[0062] Example 9: A scale inhibitor and its preparation method.

[0063] The scale inhibitor comprises, by mass percentage, 35% carboxylate-sulfonate-acrylate, 15% polyamino-polyether methylenephosphonic acid, 20% bis(1,6-hexyltriamine)pentamethylenephosphonic acid, 0.5% fatty alcohol polyoxyethylene ether, 2% sodium tungstate, 3.5% polyepoxychloropropane dimethylamine, 1.5% ε-polylysine, 2% trehalose, 0.8% tetrabutylammonium bromide, with the balance being water, for a total of 100%.

[0064] The preparation method includes the following steps: S1. At room temperature and a speed of 250 rpm, slowly add carboxylate-sulfonate-acrylate to water and stir continuously for 25 min until the polymer is completely dissolved to obtain solution A. S2. Continue to add trehalose and ε-polylysine to solution A while stirring, and continue stirring for 25 minutes until the mixture is homogeneous to obtain solution B. S3. Then, add tetrabutylammonium bromide to solution B while stirring, and stir for 18 minutes until the mixture is homogeneous to obtain solution C.

[0065] S4. Increase the rotation speed to 350 rpm and the temperature to 35℃. Slowly add diethylenetriaminepentimidephosphonic acid and polyaminopolyethermidephosphonic acid to solution C. Stir for 20 min to obtain solution D. S5. Under this condition, sodium tungstate and surfactant are added to solution D in sequence, and stirring is continued for 15 minutes to obtain solution E. S6. Finally, at 450 rpm and 35°C, a polyepoxychloropropane dimethylamine solution diluted with water is slowly added dropwise to solution E. The mixture is stirred continuously for 25 minutes, and the pH is adjusted to 7.5-8.0 to obtain the scale inhibitor #9.

[0066] Comparative Example 1: This comparative example provides a comparative dispersing scale inhibitor D1, which, by mass percentage, comprises 35% carboxylate-sulfonate-acrylate, 35% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 0.5% fatty alcohol polyoxyethylene ether, 2% sodium tungstate, 3.5% polyepoxychloropropane dimethylamine, 1.5% ε-polylysine, 2% trehalose, 0.8% tetrabutylammonium bromide, and the balance being water, for a total of 100%.

[0067] The preparation method includes the following steps: S1. At room temperature and a speed of 250 rpm, slowly add the carboxylate-sulfonate-acrylate and acrylic-2-acrylamide-2-methylpropanesulfonic acid copolymer to water and continue stirring for 25 min until the polymer is completely dissolved to obtain solution A. S2. Continue to add trehalose and ε-polylysine to solution A while stirring, and continue stirring for 25 minutes until the mixture is homogeneous to obtain solution B. S3. Then, add tetrabutylammonium bromide to solution B while stirring, and stir for 18 minutes until the mixture is homogeneous to obtain solution C.

[0068] S4. Increase the rotation speed to 350 rpm and the temperature to 35℃. Add sodium tungstate and surfactant to solution C in sequence and continue stirring for 15 min to obtain solution D. S5. Finally, at 450 rpm and 35°C, a polyepoxychloropropane dimethylamine solution diluted with water is slowly added dropwise to solution D. The mixture is stirred continuously for 25 min, and the pH is adjusted to 7.5-8.0 to obtain the comparative dispersing scale inhibitor D1.

[0069] Comparative Example 2: This comparative example provides a comparative dispersant and scale inhibitor D2, which, by mass percentage, comprises 35% polyaminopolyether methylenephosphonic acid, 35% bis(1,6-hexyltriaminepentamethylenephosphonic acid), 0.5% fatty alcohol polyoxyethylene ether, 2% sodium tungstate, 3.5% polyepoxychloropropane dimethylamine, 1.5% ε-polylysine, 2% trehalose, 0.8% tetrabutylammonium bromide, with the balance being water, for a total of 100%.

[0070] The preparation method includes the following steps: S1. At room temperature and a speed of 250 rpm, slowly add trehalose and ε-polylysine to water in sequence, and continue stirring for 25 minutes until the mixture is homogeneous to obtain solution A. S2. Then, while stirring, add tetrabutylammonium bromide to solution A and stir for 18 minutes until the mixture is homogeneous to obtain solution B.

[0071] S3. Increase the rotation speed to 350 rpm and the temperature to 35℃. Slowly add diethylenetriaminepentimidephosphonic acid and polyaminopolyetherimidephosphonic acid to solution B. Stir for 20 min to obtain solution C. S4. Under this condition, sodium tungstate and surfactant are added to solution C in sequence, and stirring is continued for 15 minutes to obtain solution D. S5. Finally, at 450 rpm and 35°C, a polyepoxychloropropane dimethylamine solution diluted with water is slowly added dropwise to solution D. The mixture is stirred continuously for 25 minutes, and the pH is adjusted to 7.5-8.0 to obtain the scale inhibitor D2.

[0072] Comparative Example 3: This comparative example provides a comparative dispersant and scale inhibitor D3, which is the same as the dispersant and scale inhibitor in Example 9, except that polydimethyldiallylammonium chloride is used instead of polyepoxychloropropane dimethylamine.

[0073] Comparative Example 4: This comparative example provides a comparative dispersant scale inhibitor D4, which is the same as the dispersant scale inhibitor in Example 9, except that chitosan is used instead of ε-polylysine.

[0074] Comparative Example 5: This comparative example provides a comparative dispersant scale inhibitor D5, which is the same as the dispersant scale inhibitor in Example 9, except that tetraoctylammonium bromide is used instead of tetrabutylammonium bromide.

[0075] The static inhibition performance of the dispersing scale inhibitors #1-#9 in Examples 1-9 and the comparative dispersing scale inhibitors D1-D5 in Comparative Examples 1-5 in inhibiting calcium sulfate scale and their dispersion stability in a high-salt environment were tested. The test results are shown in Table 1.

[0076] Test 1: According to Q / SY17126-2019 "Technical Requirements for Corrosion and Scale Inhibitors for Oilfield Water Treatment", a calcium sulfate scale inhibition experiment was conducted. The concentration of sulfate ions was 50,000 ppm, the concentration of ammonium ions was 10,000 ppm, the concentration of phosphate ions was 900 ppm, the concentration of calcium ions was 1,000 ppm, and the concentration of the reagent was 10 ppm.

[0077] Test 2: Calcium carbonate scale inhibition experiments were conducted according to GB / T16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". In Ca... 2+ Concentration of 240 mg / L, CO3 2- A mixed corrosion and scale inhibitor sample was added to a 380 mg / L solution at a dosage of 10 ppm. The solution was then allowed to stand at 60°C for 10 hours. A blank control group was prepared without the added corrosion and scale inhibitor. After cooling to room temperature, the solution was filtered, and the Ca concentration in the filtrate was determined by EDTA titration. 2+ The concentration was tested, and the scale inhibition rate was calculated using the following formula: T / % = [(K2-K1) / (K0-K1)] × 100%, where T is the scale inhibition rate; K0 is the Ca in the original solution. 2+ Concentration; K1 is the Ca concentration in the filtrate of the blank group. 2 + Concentration; K2 is the Ca in the filtrate after treatment with the corrosion and scale inhibitor sample. 2+ concentration.

[0078] Test 3 simulated the water quality conditions of typical high-salinity wastewater after being concentrated by a certain factor through reverse osmosis. In this high-ionic-strength medium, a fixed amount of standardized particulate matter (Fe2O3 powder) was added, along with 10 PPM of the dispersant scale inhibitors #1-#9 from Examples 1-9 and the comparative dispersant scale inhibitors D1-D5 from Comparative Examples 1-5. The solutions were allowed to stand at room temperature (25±0.5℃) for 24 hours to ensure the system reached a quasi-equilibrium state. Subsequently, the turbidity of the supernatant was measured using a turbidimeter.

[0079] Table 1 Turbidity is positively correlated with the concentration of stable suspended fine particles in the solution. Therefore, the higher the turbidity after standing, the stronger the ability of the scale inhibitor to inhibit particle sedimentation and agglomeration through steric hindrance and electrostatic repulsion. From the test data obtained in Examples 1-8 in Table 1, especially the test data in Example 8, it can be seen that the scale inhibition rate of calcium sulfate is greater than 92%, and the scale inhibition rate of calcium carbonate is greater than 95%. Furthermore, in the high-salt dispersion stability experiment, the turbidity of the system remained above 70 NTU. Through the reasonable ratio and synergistic effect of the components of the scale inhibitor, the scale inhibitor of this application exhibits excellent scale inhibition efficiency, superior dispersion performance, and broad adaptability to various scale types.

[0080] Compared to Example 8, Example 9, which added the water structure modifier tetrabutylammonium bromide, showed superior scale inhibition and dispersion effects compared to Example 8. This is because water molecules form dynamic clusters of varying sizes through hydrogen bonds. The tetrabutylammonium bromide contains quaternary ammonium cations ([N(C4H9)4)). + Calcium carbonate (CFC) is hydrophobic. When it enters water, to minimize the disruption of the hydrogen bond network caused by its hydrophobic surface, water molecules rearrange themselves around it, forming a more ordered and rigid structure, thus disrupting the hydrogen bond network of water molecules. Scale-forming ions (such as Ca²⁺) can also contribute to this. 2+ SO4 2- In water, these molecules are also surrounded by a hydration shell. To form crystals, they must partially shed this hydration shell to approach each other. When tetrabutylammonium bromide disrupts the hydrogen bond network of bulk water, the interaction (ion-dipole interaction) between water molecules and scale-forming ions is relatively enhanced. This indicates that ions require higher energy to escape their hydration shell, which increases the solubility of scale-forming substances, thereby delaying the formation and growth of crystal nuclei and thus increasing the solvation energy of scale-forming ions.

[0081] Compared with Example 9, Comparative Example 1 did not contain any organophosphorus compounds, and the performance of the comparative dispersant and scale inhibitor D1 was far lower than that of the dispersant and scale inhibitor #9 in Example 9.

[0082] This is because organophosphonic acid molecules in organophosphorus compounds can adsorb onto the surface of the crystal nucleus, inhibiting its continued growth. Furthermore, the phosphonic acid group (-PO3H2) has a strong effect on Ca... 2+ Mg 2+ Ba 2+ 、Sr 2+ High-valence metal ions have a strong complexing ability, which can reduce the concentration of free ions, thus making it difficult for them to form scale.

[0083] Compared with Example 9, Comparative Example 2 did not contain any polycarboxylic acid compounds, and the performance of the comparative dispersant and scale inhibitor D2 was far lower than that of the dispersant and scale inhibitor #9 in Example 9.

[0084] This is because the carboxyl group (-COO) on the molecular chain of polycarboxylic acid compounds - These molecules can adsorb onto the active growth sites of microcrystals, interfering with the ordered arrangement of the crystal lattice, causing crystal distortion, making them loose and easily washed away by water. The long polymer chains extend in water, forming a dynamic barrier. When microcrystals form, these long chains physically prevent them from approaching each other and agglomerating, keeping them dispersed. The -SO3 groups in the ionized carboxylate-sulfonate-acrylate... - This makes the polymer chains negatively charged, which electrostatically repels similarly negatively charged colloidal particles and microcrystals, preventing their deposition.

[0085] Compared to Example 9, Comparative Example 3, which used polydiallyl ammonium chloride instead of polyepichlorohydrin dimethylamine, showed significantly lower performance in all aspects of the comparative dispersant and scale inhibitor D3 compared to Example 9's dispersant and scale inhibitor #9. This is because although both polydiallyl ammonium chloride and polyepichlorohydrin dimethylamine are cationic polymers, the strong charge neutralization effect of polydiallyl ammonium chloride may lead to excessive flocculation, forming large, dense flocs. These flocs themselves may become new sources of deposition rather than being stably dispersed in the system. In contrast, polyepichlorohydrin dimethylamine, with its high positive charge density, effectively neutralizes the charge of negatively charged organic colloids, humic acids, and suspended particles in the water, and through adsorption bridging, aggregates them into larger, easily settled or filtered flocs. It can also address organic colloidal contamination that anionic scale inhibitors cannot handle, preventing these organic colloids from becoming scale binders or directly causing fouling.

[0086] Compared to Example 9, Comparative Example 4 used chitosan instead of ε-polylysine, and the resulting comparative dispersant and scale inhibitor D4 exhibited significantly lower performance than the dispersant and scale inhibitor #9 of Example 9. This is because although chitosan and ε-polylysine have similar properties, chitosan only functions under acidic conditions. In neutral to alkaline high-salt wastewater, its integration capacity and antibacterial properties decrease sharply or are even completely lost. ε-polylysine kills bacteria by disrupting cell membrane structures, while chitosan primarily works through adsorption and film formation. The former has a better immediate killing effect on planktonic bacteria in water.

[0087] Compared to Example 9, Comparative Example 5 used tetraoctylammonium bromide instead of tetrabutylammonium bromide, and the resulting comparative dispersant and scale inhibitor D5 exhibited significantly lower performance than the dispersant and scale inhibitor #9 of Example 9. This is because although both tetraoctylammonium bromide and tetrabutylammonium bromide are quaternary ammonium salts, tetraoctylammonium bromide has a longer alkyl chain, which leads to a sharp decrease in its solubility in water. The excessively long alkyl chain also results in a very low critical micelle concentration, causing micelle formation. This not only fails to help regulate water structure but also introduces problems such as foaming and emulsification.

[0088] Therefore, it can be seen that the absence or substitution of materials will not play a role in the dispersing scale inhibitor, but will instead reduce the effect of the dispersing scale inhibitor. Thus, each component cannot be arbitrarily replaced by other materials.

[0089] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A scale inhibitor suitable for dispersibility, characterized in that, The scale inhibitor comprises, by mass percentage, 25-45% polycarboxylic acid compounds, 15-25% organophosphorus compounds, 0.3-0.8% surfactant, 1-3% sodium tungstate, 2-5% polyepoxychloropropane dimethylamine, 0.5-2% ε-polylysine, 1-3% trehalose, and the balance being water.

2. The scale inhibitor according to claim 1, characterized in that, The polycarboxylic acid compound is any one or more of polyacrylic acid, polyepoxysuccinic acid, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, and carboxylate-sulfonate-acrylate.

3. The scale inhibitor according to claim 2, characterized in that, The polycarboxylic acid compound is a carboxylate-sulfonate-acrylate.

4. The scale inhibitor according to claim 1, characterized in that, The organophosphorus compound is any one or more of diethylenetriaminepentamethylenephosphonic acid, heptasodium diethylenetriaminepentamethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, polyaminopolyether methylenephosphonic acid, and bis(1,6-hexyltriaminepentamethylenephosphonic acid).

5. The scale inhibitor according to claim 4, characterized in that, The organophosphorus compound is any one or both of polyaminopolyether methylenephosphonic acid and bis(1,6-hexyltriaminepentimethylenephosphonic acid).

6. The scale inhibitor according to claim 1, characterized in that, The surfactant is a nonionic surfactant or an amphoteric surfactant; the nonionic surfactant is an alkylphenol polyoxyethylene ether or a fatty alcohol polyoxyethylene ether, and the amphoteric surfactant is cocamidopropyl betaine or sulfobetaine.

7. The scale inhibitor according to claim 1, characterized in that, The scale inhibitor also includes a water structure modifier comprising 0.5%-1% by mass, wherein the water structure modifier is tetrabutylammonium bromide.

8. A method for preparing a scale inhibitor using any one of claims 1-7, characterized in that, The preparation method includes the following steps: At room temperature and a rotation speed of 200-300 rpm, a polycarboxylic acid compound is slowly added to water and stirred continuously for 20-30 minutes until the polymer is completely dissolved. While continuing to stir, trehalose and ε-polylysine are added sequentially, and stirring is continued for 20-30 minutes until the mixture is homogeneous. The rotation speed is increased to 300-400 rpm, and the temperature is 25-40°C. An organophosphorus compound is slowly added dropwise, and stirring is continued for 15-20 minutes. Under this condition, sodium tungstate and a surfactant are added sequentially, and stirring is continued for 10-20 minutes. Finally, a diluted polyepoxychloropropane dimethylamine solution is slowly added dropwise at 400-500 rpm and 30-40°C, and stirring is continued for 20-30 minutes. The pH is adjusted to 7.5-8.0 to obtain the dispersing scale inhibitor.

9. The method for preparing a scale inhibitor according to claim 8, characterized in that, The preparation method further includes adding trehalose and ε-polylysine sequentially while stirring, stirring for 20-30 minutes until the mixture is uniform, then adding a water structure modifier and stirring for 15-20 minutes until the mixture is uniform.

10. The application of a dispersant and scale inhibitor in high-salinity wastewater generated in the coal chemical industry, oil and gas extraction industry, seawater desalination industry, and fine chemical industry, characterized in that... The dispersing scale inhibitor is prepared using the dispersing scale inhibitor as described in any one of claims 1-7 or the preparation method of the dispersing scale inhibitor as described in any one of claims 8-9.

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