A dispersing scale inhibitor and a method for preparing the same

Abstract

The present application relates to a kind of dispersing scale inhibitor and its preparation method, it is related to water treatment technical field, wherein, by mass percentage, the dispersing scale inhibitor includes polycarboxylic compound 25-45%, organic phosphine compound 15-25%, surfactant 0.3-0.8%, sodium tungstate 1-3%, polyepoxy chloropropane dimethylamine 2-5%, epsilon-polylysine 0.5-2%, trehalose 1-3%, and the balance is water.The dispersing scale inhibitor of the present application has excellent scale inhibition efficiency, outstanding dispersing performance, extensive scale species adaptability and good high-temperature stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and particularly relates to a dispersing scale inhibitor and a preparation method thereof. BACKGROUND

[0002] With the rapid development of coal chemical industry, oil and gas exploitation, seawater desalination and fine chemical industry, the discharge of high-salinity wastewater has increased dramatically, and the total dissolved solids (TDS) thereof is usually more than 10,000 mg / L, and even can reach a saturated state. Direct discharge of such wastewater will pose a serious threat to aquatic ecosystems and soil environments, therefore, realizing the resource recycling and “zero discharge” of high-salinity wastewater has become a mandatory requirement for industrial sustainable development and environmental protection regulations. In the mainstream “zero discharge” process route, membrane concentration (such as reverse osmosis and nanofiltration) and evaporation crystallization are the core units for realizing water recovery and salt solidification. However, in this process, the dissolved salts are highly concentrated and are prone to exceed their solubility product constant, thereby forming a dense scale layer on the membrane surface and the evaporator heat exchange wall, which causes a series of problems such as membrane flux attenuation, system operating pressure rise, and significant decrease in heat transfer efficiency, thereby seriously restricting the stability and economy of the entire treatment process.

[0003] Adding a scale inhibitor is the most economical and effective technical means to alleviate the above-mentioned scaling problems. Its action mechanism is mainly based on threshold effect, lattice distortion and dispersion effect. However, the performance of conventional scale inhibitors faces severe challenges in extreme working conditions of high salinity, high hardness and high temperature: (1) high concentration of background electrolytes (such as Na⁺ and Cl⁻) will produce a strong “salt effect”, shielding the electrostatic interaction between the functional groups of the scale inhibitor and the scaling ions (such as Ca²⁺, Ba²⁺ and Sr²⁺), resulting in a significant weakening of the threshold effect; (2) traditional polycarboxylic acid scale inhibitors are prone to cross-linking reactions with high-valence metal ions, forming insoluble flocs or precipitates, not only losing the scale inhibition function, but also possibly becoming a new source of pollution; (3) in a high ionic strength environment, the double electric layer of colloidal particles is strongly compressed, making the dispersion system relying on electrostatic repulsion unstable, resulting in rapid aggregation and deposition of microcrystals.

[0004] A Chinese invention patent with publication number CN105502703A discloses a kind of compound high-efficiency scale inhibitor, including the following weight parts components: initiator 15~25 parts, monomer raw material 10~15 parts, compound agent 20~30 parts, solvent 15~20 parts, auxiliary 30~50 parts;Wherein, the initiator is sodium bisulfite and ammonium persulfate mixture, the monomer raw material is the mixture of acrylic acid and 2-acrylamide-2-methylpropane sulfonic acid, the compound agent is 2-phosphine acyl butane-1,2,4-tricarboxylic acid, the solvent is deionized water, and the auxiliary is the mixture of epoxy resin, amino resin, rust inhibitor and preservative.By introducing 2-acrylamide-2-methylpropane sulfonic acid and other sulfonic acid monomers, copolymerization is carried out with carboxylic acid monomers (such as acrylic acid) and non-ionic monomers, the excellent hydration capacity and anti-ion interference characteristics of sulfonic acid group are used to improve the calcium tolerance and dispersibility of the polymer.Although the above-mentioned scale inhibitor achieves good scale inhibition effect, its inherent defects are still very prominent: (1) the conformational stability of polymer molecular chain is poor, and it is easy to curl under high ionic strength, which weakens its steric hindrance effect and leads to the decline of dispersion capacity for submicron crystal nucleus; (2) the single polymer molecular structure is difficult to simultaneously produce optimal synergistic inhibition effect on various scales such as silica scale, iron scale, calcium scale and barium scale under complex and variable water quality conditions; (3) under the high temperature (>100°C) environment in the evaporation crystallization stage, the polymer chain may be hydrolyzed or thermally degraded, resulting in poor long-term stability.

[0005] Therefore, it is an urgent technical requirement to develop a scale inhibitor with excellent scale inhibition efficiency, excellent dispersion performance, wide scale adaptability and good high-temperature stability. SUMMARY

[0006] To solve the above technical problems, the present application provides a kind of dispersion scale inhibitor and preparation method thereof.The dispersion scale inhibitor of the present application has excellent scale inhibition efficiency, excellent dispersion performance, wide scale adaptability and good high-temperature stability.

[0007] In a first aspect, the present application provides a kind of dispersion scale inhibitor, by mass percentage, the dispersion scale inhibitor includes polycarboxylic acid compound 25-45%, organic phosphine compound 15-25%, surfactant 0.3-0.8%, sodium tungstate 1-3%, polyepoxy chloropropane dimethylamine 2-5%, epsilon-polylysine 0.5-2%, trehalose 1-3%, and the balance is water.

[0008] In the above technical solution, the polycarboxylic compound and the organic phosphine compound are used as main components. The polycarboxylic compound mainly provides steric hindrance and lattice distortion effect, and is responsible for dispersing the microcrystalline particles. The organic phosphine compound mainly provides chelation and threshold effect, and directly inhibits the nucleation and growth of scale. Through the compounding of the polycarboxylic compound and the organic phosphine compound, mechanism complementation and synergistic effect are achieved, which can significantly improve the inhibition efficiency of common scales such as calcium sulfate, calcium carbonate and other difficult-to-dissolve scales such as barium sulfate and strontium sulfate with low solubility product. The optimized functional group ratio and molecular weight distribution of the polymer, combined with the stabilizing effect of the organic phosphine, enable the dispersing scale inhibitor to effectively maintain the molecular chain conformation in a high ionic strength environment, providing stronger steric hindrance and electrostatic stabilization. Moreover, the selected polycarboxylic compound and organic phosphine compound have good stability, so that the overall dispersing scale inhibitor has good high-temperature resistance, allowing it to maintain long-term chemical stability and scale inhibition activity under high-temperature process conditions such as evaporation crystallization, with a low performance decay rate.

[0009] The surface active agent can reduce the surface tension of the liquid and wastewater, making it easier to spread and penetrate on the membrane surface, heat exchange tube wall or existing soft scale, so that the main scale inhibitor component can more effectively reach the action site, and also help to peel off the loose scale layer and sticky mud that has been formed.

[0010] The tungstate ion (WO4 2- ) in sodium tungstate can migrate to the anode area 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 oxide, which can greatly prevent further corrosion of the metal.

[0011] Polyepoxy chloropropane dimethylamine, as a cationic polymer, effectively neutralizes the charges of negatively charged organic colloids, humic acid and suspended particles in water through its high positive charge density, and through adsorption bridging, it agglomerates them into larger, easily settled or filtered flocs. It can also deal with organic colloid pollution that anionic scale inhibitors cannot handle, preventing these organic colloids from becoming scale binders or directly causing blockage.

[0012] Free Fe 3+ , Al 3+ , Cu 2+ high-valent metal ions in water can easily form insoluble gels or precipitates with polycarboxylic compounds and organic phosphonic acid compounds, causing the main agent to fail. The abundant amino groups (-NH2) on the molecular chain of ε-polylysine can effectively integrate with free Fe 3+ , Al 3+ , Cu 2+ high-valent metal ions in water, preventing the formation of insoluble gels and precipitates. As a natural antibacterial agent, ε-polylysine can inhibit the growth of bacteria in the system and prevent the formation of biological slime by bacteria.

[0013] Trehalose molecules have strong hydrogen bond formation ability. In high salt, high temperature and other stress environments, it can partially wrap around the polymer and organic phosphonic acid molecules through hydrogen bonds to form a protective hydration layer, which can slow down the breakage of polymer chains at high temperature and slow down the chemical degradation of organic phosphonic acid molecules. Help polycarboxylic acid molecules resist chain curling at high ionic strength, maintain extended conformation, and thus maintain its steric hindrance effect.

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

[0015] In the above technical solution, the carboxyl groups (-COO - ) on the molecular chain of the polycarboxylic compound can be adsorbed on the active growth point of the microcrystal, interfere with the ordered arrangement of the crystal lattice, cause the crystal to be distorted, become loose, and be easily washed away by water flow. The long chains of the polymer stretch in water to form a dynamic barrier. When the microcrystals form, these long chains will physically block the microcrystals from approaching and aggregating to grow, so that they remain in a dispersed state. The carboxyl groups and sulfonic acid groups (such as -SO3 - ) after ionization make the polymer chain negatively charged, which electrostatically repels colloid particles and microcrystals that are also negatively charged, preventing their deposition.

[0016] Optionally, the organic phosphorus compound is any one or several of diethylenetriamine pentamethylene phosphonic acid, diethylenetriamine pentamethylene phosphonic acid seven sodium, 2-phosphonobutane-1,2,4-tricarboxylic acid, polyamino polyether methyl phosphonic acid, and bis 1,6-hexylene triamine pentamethylene phosphonic acid; preferably, the organic phosphorus compound is any one or both of polyamino polyether methyl phosphonic acid and bis 1,6-hexylene triamine pentamethylene phosphonic acid.

[0017] In the above technical solution, the organic phosphonic acid molecules in the organic phosphorus compound can be adsorbed on the surface of the crystal nucleus to inhibit its continued growth. And the phosphonic acid group (-PO3H2) has a strong complexing ability for high-valent metal ions such as Ca 2+ , Mg 2+ , Ba 2+ , Sr 2+ , which can reduce the concentration of free ions, making it difficult to form scale.

[0018] Optionally, the surfactant is a non-ionic surfactant or a zwitterionic surfactant; the non-ionic surfactant is an alkyl phenol polyoxyethylene ether or a fatty alcohol polyoxyethylene ether, and the zwitterionic surfactant is cocamidopropyl betaine or sulfobetaine.

[0019] In the above technical solution, the nonionic surfactant has the advantages of high concentration acid and alkali resistance, hard water resistance, and oxidant resistance. It is very stable in an environment with high salt and possible presence of chlorine and other oxidizing bactericides. It also has good spreading and penetration ability on organic scale and metal surfaces, which can help the effective components of the scale inhibitor penetrate into the scale layer.

[0020] The zwitterionic surfactant has positive and negative charges, and can be well compatible with anions, cations, and nonionic substances, so that the charge conflict when compounded with polycarboxylic acid (anion) and polyepoxy chloropropane dimethylamine (cation) can be avoided. The zwitterionic molecule can form a dense and highly hydrated protective layer on the membrane surface or metal equipment surface through strong electric dipole effect. This hydrated layer can physically repel the approach and adhesion of inorganic crystallites, organic colloids, biological macromolecules, and other pollutants. It usually has little irritation and good biodegradability. It can maintain stable performance in a wide pH range.

[0021] Optionally, the dispersing scale inhibitor further comprises 0.5-1% by mass of a water structure regulator, and the water structure regulator is tetrabutylammonium bromide.

[0022] In the above technical solution, water molecules form dynamic and variously sized water molecule clusters through hydrogen bonds. The quaternary ammonium cation ([N(C4H9)4] + ) in tetrabutylammonium bromide has hydrophobicity. When it enters water, in order to minimize the destruction of the hydrogen bond network by the hydrophobic surface, water molecules will rearrange around it to form a more ordered and rigid structure, thereby destroying the hydrogen bond network of water molecules. Scale-forming ions (such as Ca 2+ , SO4 2- ) are also surrounded by a hydration shell in water. To form crystals, they must partially remove this hydration shell to approach each other. When tetrabutylammonium bromide destroys the hydrogen bond network of bulk water, the interaction between water molecules and scale-forming ions (ion-dipole interaction) is relatively enhanced. This indicates that ions need higher energy to get rid of 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] In a second aspect, the present application provides a preparation method of the dispersant scale inhibitor, which comprises the following steps: slowly adding a polycarboxylic compound into water under the condition of room temperature and a stirring speed of 200-300 rpm, continuously stirring for 20-30 min until the polymer is completely dissolved, then adding trehalose and ε-polylysine into the solution in sequence under the condition of continuous stirring, continuously stirring for 20-30 min until the mixture is uniformly mixed, increasing the stirring speed to 300-400 rpm, and adding an organic phosphine compound slowly and dropwise under the condition of a temperature of 25-40 ℃, continuously stirring for 15-20 min, then adding sodium tungstate and a surfactant into the solution in sequence under the condition of continuous stirring, continuously stirring for 10-20 min, and finally adding a polyepoxy chloropropane dimethylamine solution diluted with water slowly and dropwise under the condition of a stirring speed of 400-500 rpm and a temperature of 30-40 ℃, continuously stirring for 20-30 min, and adjusting the pH to 7.5-8.0 to obtain the dispersant scale inhibitor.

[0024] In the above technical solution, the molecular chain of the polycarboxylic compound needs to be stretched and hydrated in water to form a uniform dispersion system. Therefore, the complete dissolution process of the polymer plays an important role in the subsequent space steric effect. The reason for mixing trehalose and ε-polylysine with the polymer solution in advance is that ε-polylysine can integrate trace amounts of high-valence metal ions possibly existing in water in advance, and trehalose can interact with the polymer molecules through hydrogen bonds to establish a protective environment in advance and prepare for subsequent high temperature or chemical stress. The organic phosphine compound is usually acidic and highly concentrated, and rapid and large addition can cause local overheating and sudden pH drop, which can easily cause the polycarboxylic acid molecular chain to curl and even precipitate. Slow dropwise addition can ensure that the system is mixed smoothly and gently. Under mild conditions, the organic phosphine compound and the polycarboxylic acid polymer can be bridged by calcium ions or directly form weak intermolecular forces to construct a synergistic composite structure in advance, rather than simply physically mixed. Adding sodium tungstate first and then adding the surfactant can avoid the salting-out and coagulation of the surfactant when it encounters high-concentration electrolytes, ensuring its uniform dispersion. The polyepoxy chloropropane dimethylamine has strong positive charge, and the polycarboxylic acid polymer has strong negative charge. Direct and rapid mixing can instantly produce strong electric neutralization effect, forming insoluble macromolecular complex precipitates. Diluting the polyepoxy chloropropane dimethylamine first and then slowly and dropwise adding it under high-speed stirring can make the cationic polymer quickly dispersed into the whole system when it contacts the anionic polymer, so that it can only act on small colloidal particles rather than macroscopically react with the main scale inhibitor. Adjusting the pH to neutral or slightly alkaline is friendly to the equipment and can maintain the chemical stability of each component. Too low pH can accelerate the corrosion of the equipment and may make some components unstable; too high pH may promote the formation of hydroxide precipitates of calcium and magnesium ions.

[0025] Optionally, the preparation method further comprises sequentially adding trehalose and epsilon-polylysine under continuous stirring, continuing to stir for 20-30 min until mixed uniformly, and then adding a water structure regulator, stirring for 15-20 min until mixed uniformly.

[0026] In the above technical solution, the water structure regulator is added early, which can provide sufficient time and homogeneous environment for it to fully interact with water molecules, destroy the original hydrogen bond network, and thus prepare a solvent environment that can inhibit fouling when subsequent scale-forming ions are added.

[0027] The polycarboxylic acid polymer has been fully hydrated and stretched to form a stable dispersion system. At this time, the water structure regulator is added, and its cationic nature meets the anionic polymer. However, because it is in a stable system and the concentration is very low, it is not enough to cause flocculation, but it can start to work under mild conditions.

[0028] Organic phosphonic acid compounds are strong acidic and high concentration components. Their addition will cause a sharp change in the pH and ionic strength of the system. By allowing the water structure regulator to be uniformly dispersed before this change, a series of reactions can be avoided.

[0029] By separating the addition time of the water structure regulator from the addition time of the polyepoxy chloropropane dimethylamine, the stability of the system caused by the charge synergistic effect of the two positively charged substances can be maximized.

[0030] In a third aspect, the present application provides a preparation process for a dispersing scale inhibitor or the application of a dispersing scale inhibitor in high-salinity wastewater generated in the coal chemical industry, the oil and gas exploration industry, the seawater desalination industry, and the fine chemical industry.

[0031] In summary, the present application includes at least one of the following beneficial technical effects:

[0032] 1. By adding polycarboxylic acid compounds and organic phosphorus compounds, the mechanism of complementation and synergistic effect is achieved through the compounding of the two, which can significantly improve the high-temperature resistance of the dispersing scale inhibitor, so that it can still maintain long-term chemical stability and scale inhibition activity under high-temperature process conditions such as evaporation crystallization.

[0033] 2. By adding a surfactant, the surface tension of the liquid and wastewater can be reduced, making it easier to spread and penetrate on the membrane surface, heat exchange tube wall, or existing soft scale, so that the main scale inhibitor component can more effectively reach the action site, and also help to peel off the loose scale layer and sticky mud that has been formed.

[0034] 3. By adding polyepoxy chloropropane dimethylamine, its high density of positive charge can effectively neutralize the charge of the negatively charged organic colloid, humic acid and suspended particles in water, and through adsorption bridging, it can agglomerate them into larger, easy to settle or filter flocculation. It can also prevent organic colloid pollution that anion scale inhibitors cannot handle from becoming scale adhesives or directly causing blockage.

[0035] 4. By adding water structure regulator, it can destroy the cluster structure of water molecules, increase the disorder degree of water, and also can increase the solvation energy of scale forming ions, improve the solubility of scale, and delay nucleation. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is the high-salt wastewater calcium sulfate scale inhibition effect diagram of the embodiment, the comparative example and the blank control of the present application. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below in combination with the embodiments.

[0038] The materials used in the following examples can be obtained by market purchase.

[0039] Example 1: A dispersing scale inhibitor and a preparation method thereof.

[0040] The dispersing scale inhibitor includes, by mass percentage, 25% of polyacrylic acid, 10% of polyepoxysuccinic acid, 15% of heptasodium diethylenetriamine pentamethylene phosphonic acid, 0.3% of alkylphenol polyoxyethylene ether, 1% of sodium tungstate, 2% of polyepoxy chloropropane dimethylamine, 0.5% of ε-polylysine, 1% of trehalose, and the balance is water, with the total amount being 100%.

[0041] The preparation method includes the following steps:

[0042] S1. Under the condition of room temperature, polyacrylic acid and polyepoxysuccinic acid are slowly added to water at a stirring speed of 250 rpm, and the stirring is continued for 25 min until the polymers are completely dissolved, to obtain solution A;

[0043] S2. Trehalose and ε-polylysine are sequentially added to solution A under the condition of continuous stirring, and the stirring is continued for 25 min until the mixture is uniformly mixed, to obtain solution B;

[0044] S3. The stirring speed is increased to 350 rpm, and the temperature is 35℃, and heptasodium diethylenetriamine pentamethylene phosphonic acid is slowly added dropwise to solution B, and the stirring is continued for 20 min, to obtain solution C;

[0045] S4. Tungsten sodium and alkylphenol polyoxyethylene ether are sequentially added to solution C under the condition of continuous stirring, and the stirring is continued for 15 min, to obtain solution D;

[0046] S5, finally, a polyepoxy chloropropane dimethylamine solution diluted with water is slowly added to solution D at 450 rpm, 35°C, stirring is continued for 25 min, the pH is adjusted to 7.5-8.0, and the dispersant scale inhibitor #1 is obtained.

[0047] Example 2: A dispersant scale inhibitor and a method for preparing the same.

[0048] The dispersant scale inhibitor comprises, by mass percentage, acrylic acid-2-acrylamide-2-methylpropane sulfonic acid copolymer 45%, diethylene triamine penta methylene phosphonic acid 15%, 2-phosphonic butane-1,2,4-tricarboxylic acid 10%, cocamide propyl betaine 0.8%, sodium tungstate 3%, polyepoxy chloropropane dimethylamine 5%, ε-polylysine 2%, trehalose 3%, and the balance is water, with the total amount being 100%.

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

[0050] Example 3: A dispersant scale inhibitor and a method for preparing the same.

[0051] The dispersant scale inhibitor comprises, by mass percentage, polyacrylic acid 20%, acrylic acid-2-acrylamide-2-methylpropane sulfonic acid copolymer 25%, diethylene triamine penta methylene phosphonic acid 10%, bis 1,6-hexylene triamine penta methylene phosphonic acid 10%, fatty alcohol polyoxyethylene ether 0.5%, sodium tungstate 2%, polyepoxy chloropropane dimethylamine 3%, ε-polylysine 1%, trehalose 2%, and the balance is water, with the total amount being 100%.

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

[0053] Example 4: A dispersant scale inhibitor and a method for preparing the same.

[0054] The dispersant scale inhibitor comprises, by mass percentage, carboxylate-sulfonate-acrylate 20%, polyepoxy succinic acid 10%, polyamino polyether-based methylene phosphonic acid 20%, sulfobetaine 0.6%, sodium tungstate 1.5%, polyepoxy chloropropane dimethylamine 3%, ε-polylysine 1.5%, trehalose 1.5%, and the balance is water, with the total amount being 100%.

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

[0056] Example 5: A dispersant scale inhibitor and a method for preparing the same.

[0057] The dispersant scale inhibitor comprises, by mass percentage, carboxylate-sulfonate-acrylate 30%, diethylene triamine penta methylene phosphonic acid 5%, 2-phosphonobutane-1,2,4-tricarboxylic acid 20%, alkylphenol polyoxyethylene ether 0.4%, sodium tungstate 2%, polyepoxy chloropropane dimethylamine 4%, ε-polylysine 1.2%, trehalose 2%, and the balance is water, with a total amount of 100%.

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

[0059] Example 6: A dispersant scale inhibitor and a preparation method thereof.

[0060] The dispersant scale inhibitor comprises, by mass percentage, carboxylate-sulfonate-acrylate 30%, polyamino polyether methylene phosphonic acid 25%, fatty alcohol polyoxyethylene ether 0.5%, sodium tungstate 2%, polyepoxy chloropropane dimethylamine 3.5%, ε-polylysine 1%, trehalose 2%, and the balance is water, with a total amount of 100%.

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

[0062] Example 7: A dispersant scale inhibitor and a preparation method thereof.

[0063] The dispersant scale inhibitor comprises, by mass percentage, carboxylate-sulfonate-acrylate 40%, bis 1,6-hexylene triamine penta methylene phosphonic acid 20%, cocamide propyl betaine 0.6%, sodium tungstate 2%, polyepoxy chloropropane dimethylamine 3%, ε-polylysine 1.5%, trehalose 2%, and the balance is water, with a total amount of 100%.

[0064] The preparation method is the same as that of Example 1.

[0065] Example 8: A dispersant scale inhibitor and a preparation method thereof.

[0066] The dispersant scale inhibitor comprises, by mass percentage, carboxylate-sulfonate-acrylate 35%, polyamino polyether methylene phosphonic acid 15%, bis 1,6-hexylene triamine penta methylene phosphonic acid 20%, fatty alcohol polyoxyethylene ether 0.5%, sodium tungstate 2%, polyepoxy chloropropane dimethylamine 3.5%, ε-polylysine 1.5%, trehalose 2%, and the balance is water, with a total amount of 100%.

[0067] The preparation method is the same as that of Example 1.

[0068] Example 9: A dispersant scale inhibitor and a preparation method thereof.

[0069] The dispersant scale inhibitor comprises, by mass percentage, carboxylate-sulfonate-acrylate 35%, polyamino polyether-based methylene phosphonic acid 15%, bis 1,6-hexylene triamine penta methylene phosphonic acid 20%, fatty alcohol polyoxyethylene ether 0.5%, sodium tungstate 2%, polyepichlorohydrin dimethylamine 3.5%, epsilon-polylysine 1.5%, trehalose 2%, 0.8% tetrabutyl ammonium bromide, and the balance being water, with the total being 100%.

[0070] The preparation method comprises the following steps:

[0071] S1, under the condition of room temperature and rotation speed of 250 rpm, carboxylate-sulfonate-acrylate is slowly added to water, and stirring is continued for 25 min until the polymer is completely dissolved to obtain solution A;

[0072] S2, trehalose and epsilon-polylysine are sequentially added to solution A under the condition of continuous stirring, and stirring is continued for 25 min until the mixture is uniform to obtain solution B;

[0073] S3, then tetrabutyl ammonium bromide is added to solution B under the condition of stirring, and stirring is continued for 18 min until the mixture is uniform to obtain solution C.

[0074] S4, the rotation speed is increased to 350 rpm, and the temperature is 35℃, diethylenetriamine pentamethylene phosphonic acid and polyamino polyether-based methylene phosphonic acid are slowly added dropwise to solution C, and stirring is continued for 20 min to obtain solution D;

[0075] S5, under this condition, sodium tungstate and surfactant are sequentially added to solution D, and stirring is continued for 15 min to obtain solution E;

[0076] S6, finally, under the condition of 450 rpm and 35℃, the polyepichlorohydrin dimethylamine solution diluted with water is slowly added dropwise to solution E, and stirring is continued for 25 min, and the pH is adjusted to 7.5-8.0 to obtain the dispersant scale inhibitor #9.

[0077] Comparative Example 1: The present comparative example provides a comparative dispersant scale inhibitor D1, which comprises, by mass percentage, carboxylate-sulfonate-acrylate 35%, acrylic acid-2-acrylamide-2-methylpropane sulfonic acid copolymer 35%, fatty alcohol polyoxyethylene ether 0.5%, sodium tungstate 2%, polyepichlorohydrin dimethylamine 3.5%, epsilon-polylysine 1.5%, trehalose 2%, 0.8% tetrabutyl ammonium bromide, and the balance being water, with the total being 100%.

[0078] The preparation method comprises the following steps:

[0079] 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.

[0080] 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.

[0081] S3. Then, add tetrabutylammonium bromide to solution B while stirring, and stir for 18 minutes until the mixture is homogeneous to obtain solution C.

[0082] 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.

[0083] 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.

[0084] 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%.

[0085] The preparation method includes the following steps:

[0086] 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.

[0087] S2. Then, while stirring, add tetrabutylammonium bromide to solution A and stir for 18 minutes until the mixture is homogeneous to obtain solution B.

[0088] 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.

[0089] 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.

[0090] S5, finally, a polyepoxy chloropropane dimethylamine solution diluted with water was slowly added to solution D at 450 rpm and 35°C, stirring was continued for 25 min, the pH was adjusted to 7.5-8.0, to obtain the dispersant antifouling agent D2.

[0091] Comparative Example 3: This comparative example provides a comparative dispersant antifouling agent D3, which is the same as the dispersant antifouling agent of Example 9, except that polydimethyl diallyl ammonium chloride is selected instead of polyepoxy chloropropane dimethylamine.

[0092] Comparative Example 4: This comparative example provides a comparative dispersant antifouling agent D4, which is the same as the dispersant antifouling agent of Example 9, except that chitosan is selected instead of ε-polylysine.

[0093] Comparative Example 5: This comparative example provides a comparative dispersant antifouling agent D5, which is the same as the dispersant antifouling agent of Example 9, except that tetraoctyl ammonium bromide is selected instead of tetrabutyl ammonium bromide.

[0094] The dispersant antifouling agents #1-#9 of Examples 1-9 and the comparative dispersant antifouling agents D1-D5 in Comparative Examples 1-5 were tested for static state resistance to calcium sulfate scale and dispersant stability in a high salt environment, and the test results are shown in Table 1.

[0095] Test One: The calcium sulfate scale inhibition experiment was carried out according to Q / SY17126-2019 “Technical Requirements for Inhibiting and Scale Inhibiting Agents for Oilfield Water Treatment”. The concentration of sulfate ions was 50000 ppm, the concentration of ammonium ions was 10000 ppm, the concentration of phosphate ions was 900 ppm, the concentration of calcium ions was 1000 ppm, and the concentration of the agent was 10 ppm.

[0096] Test Two: The calcium carbonate scale inhibition experiment was carried out according to GB / T16632-2019 “Determination of Scale Inhibition Performance of Water Treatment Agents by Calcium Carbonate Deposition Method”. The concentration of Ca 2+ was 240 mg / L, the concentration of CO3 2- was 380 mg / L, the mixed scale and corrosion inhibitor sample was added in an amount of 10 ppm, then it was placed at 60°C for 10 h, the blank group was not added with the scale and corrosion inhibitor sample, after the temperature was reduced to room temperature, it was filtered, the concentration of Ca 2+ in the filtrate was tested by EDTA titration method, and the scale inhibition rate calculation formula was as follows: T / % = [(K2-K1) / (K0-K1)]x100%, wherein T was the scale inhibition rate, K0 was the concentration of Ca 2+ in the original solution, K1 was the concentration of Ca 2 + in the filtrate of the blank group, and K2 was the concentration of Ca 2+ in the filtrate after the scale and corrosion inhibitor sample treatment.

[0097] Test three, simulated the water quality condition of typical high salt wastewater after concentrated by reverse osmosis. In this high ionic strength medium, add quantitative standard particles (Fe2O3 powder), and respectively add 10 PPM of dispersant scale inhibitors #1-#9 of examples 1-9 and comparative dispersant D1-D5 of comparative examples 1-5. The solution is placed at room temperature (25±0.5℃) for 24h to ensure that the system reaches quasi-equilibrium state, then the turbidity of supernatant is measured by turbidimeter.

[0098] Table 1

[0099]

[0100] The turbidity value is positively correlated with the concentration of stable suspended fine particles in the solution, therefore, the higher the turbidity value after standing, the stronger the ability of scale inhibition dispersant to inhibit particle settlement and agglomeration through steric hindrance and electrostatic repulsion effect. As can be seen from the test data of examples 1-8 in table 1, especially the test data of example 8, the calcium sulfate scale inhibition rate is greater than 92%, the calcium carbonate scale inhibition rate is greater than 95%, and the system turbidity is maintained above 70 NTU in the high salt dispersion stability experiment. Through reasonable matching and synergistic effect of the composition of the dispersant scale inhibitor, the dispersant scale inhibitor of the application has excellent scale inhibition efficiency, excellent dispersion performance and wide scale species adaptability.

[0101] Compared with example 8, dispersant scale inhibitor #9 adds water structure regulator tetrabutylammonium bromide, and the scale inhibition effect and dispersion effect of dispersant scale inhibitor #9 are better than those of dispersant scale inhibitor #8, because water molecules form dynamic water molecule clusters of different sizes through hydrogen bonds. The quaternary ammonium cation ([N(C4H9)4] + ) in tetrabutylammonium bromide has hydrophobicity. When it enters water, in order to minimize the destruction of the hydrogen bond network by the hydrophobic surface, water molecules will rearrange around it to form a more ordered and rigid structure, thereby destroying the hydrogen bond network of water molecules. The scale forming ions (such as Ca 2+ , SO4 2- ) are also surrounded by a hydration shell in water. To form crystals, they must partially remove this hydration shell to approach each other. When tetrabutylammonium bromide destroys the hydrogen bond network of bulk water, the interaction between water molecules and scale forming ions (ion-dipole interaction) is relatively enhanced. This means that ions need higher energy to get rid of their hydration shell, which increases the solubility of scale forming substances, thereby delaying the formation and growth of crystal nucleus, and improving the solvation energy of scale forming ions.

[0102] Compared with example 9, comparative example 1 does not add organic phosphine compounds, and the performance of comparative dispersant D1 obtained is much lower than that of dispersant scale inhibitor #9 of example 9.

[0103] This is because the organic phosphonic acid molecules in the organic phosphine compounds can be adsorbed on the surface of the crystal nucleus to inhibit its continued growth. And the phosphonic acid group (-PO3H2) has a strong complexing ability for high-valence metal ions such as Ca 2+ , Mg 2+ , Ba 2+ , Sr 2+ , etc., can reduce the free ion concentration, so it is difficult to form scale.

[0104] Comparative Example 2, compared with Example 9, did not add polycarboxylic acid compounds, and the properties of the comparative dispersant scale inhibitor D2 obtained were much lower than those of the dispersant scale inhibitor #9 of Example 9.

[0105] This is because the carboxyl group (-COO - ) on the molecular chain of the polycarboxylic acid compound can be adsorbed on the active growth point of the microcrystal to interfere with the ordered arrangement of the crystal lattice, causing the crystal to become distorted, loose, and easy to be washed away by water flow. The long chains of the polymer stretch in water to form a dynamic barrier. When the microcrystals form, these long chains will physically block the microcrystals from approaching and aggregating to grow, keeping them in a dispersed state. The -SO3 - in the ionized carboxylate-sulfonate-acrylate makes the polymer chain negatively charged, which electrostatically repels colloidal particles and microcrystals that are also negatively charged, preventing their deposition.

[0106] Comparative Example 3, compared with Example 9, used polydimethyl diallyl ammonium chloride instead of polyepoxy chloropropane dimethylamine, and the properties of the comparative dispersant scale inhibitor D3 obtained were much lower than those of the dispersant scale inhibitor #9 of Example 9. This is because polydimethyl diallyl ammonium chloride and polyepoxy chloropropane dimethylamine are both polymers with positive ions, but the strong electro-neutralization of polydimethyl diallyl ammonium chloride can lead to excessive flocculation, forming large and dense flocs that can themselves become new deposition sources rather than being stably dispersed in the system. While polyepoxy chloropropane dimethylamine effectively neutralizes the charges of negatively charged organic colloids, humic acid, and suspended particulate matter in water through its high positive charge density, and through adsorption bridging, it agglomerates them into larger, easily settling or filtering flocs. It can also prevent organic colloids that anionic scale inhibitors cannot handle from becoming scale binders or directly causing blockage.

[0107] Compared with example 9, the shellfish polysaccharide is used instead of ε-polylysine in the comparative example 4, and the properties of the comparative dispersant D4 are far lower than those of the dispersant #9 in example 9. This is because the shellfish polysaccharide and ε-polylysine have similar properties, but the shellfish polysaccharide is positively charged and plays a role only in acidic conditions. In neutral to alkaline high-salinity wastewater, its integration ability and antibacterial property decrease sharply or even completely lose. The ε-polylysine kills bacteria by destroying the cell membrane structure, while the shellfish polysaccharide mainly absorbs and forms a film. The former has a better immediate killing effect on planktonic bacteria in the water body.

[0108] Compared with example 9, the tetraoctyl ammonium bromide is used instead of tetrabutyl ammonium bromide in the comparative example 5, and the properties of the comparative dispersant D5 are far lower than those of the dispersant #9 in example 9. This is because the tetraoctyl ammonium bromide and tetrabutyl ammonium bromide are both quaternary ammonium salts, but the alkyl chain of the tetraoctyl ammonium bromide is too long, which leads to a sharp decrease in its solubility in water. The too long alkyl chain also makes the critical micelle concentration very low, and micelles are formed, which not only does not help the water structure regulation, but also brings the problems of foam and emulsification.

[0109] Therefore, the materials that are missing or replaced cannot play a role in the dispersant, but rather reduce the effect of the dispersant, so each component cannot be replaced by other materials at will.

[0110] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made on the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A dispersant scale inhibitor characterized by, The dispersant scale inhibitor comprises, by mass percentage, 25-45% of polycarboxylic compound, 15-25% of organic phosphine compound, 0.3-0.8% of surfactant, 1-3% of sodium tungstate, 2-5% of polyepoxy chloropropane dimethylamine, 0.5-2% of epsilon-polylysine, 1-3% of trehalose, and the balance of water; The polycarboxylic compound is carboxylate-sulfonate-acrylate; The organic phosphine compound is any one or both of polyamino polyether methylidene phosphonic acid and bis 1,6-hexylene triamine penta-methylidene phosphonic acid; The surfactant is non-ionic surfactant or zwitterionic surfactant; the non-ionic surfactant is alkyl phenol polyoxyethylene ether or fatty alcohol polyoxyethylene ether, and the zwitterionic surfactant is cocamide propyl betaine or sulfobetaine; The dispersant scale inhibitor further comprises 0.5-1% of water structure regulator by mass percentage, and the water structure regulator is tetrabutyl ammonium bromide; The preparation method of the dispersant scale inhibitor comprises the following steps: slowly adding the polycarboxylic compound into water at room temperature under the stirring speed of 200-300 rpm, continuously stirring for 20-30 min until the polymer is completely dissolved, sequentially adding trehalose and epsilon-polylysine under stirring, continuously stirring for 20-30 min until the mixture is uniform, then adding the water structure regulator, stirring for 15-20 min until the mixture is uniform, increasing the stirring speed to 300-400 rpm, and slowly dropping the organic phosphine compound at the temperature of 25-40℃, stirring for 15-20 min, sequentially adding sodium tungstate and surfactant under the same condition, and continuously stirring for 10-20 min, finally slowly dropping the polyepoxy chloropropane dimethylamine solution diluted with water at the stirring speed of 400-500 rpm and the temperature of 30-40℃, continuously stirring for 20-30 min, adjusting the pH to 7.5-8.0, and obtaining the dispersant scale inhibitor.

2. Application of dispersing scale inhibitors in high-salinity wastewater generated in coal chemical industry, oil and gas exploitation industry, seawater desalination industry and fine chemical industry, characterized in that, The dispersant scale inhibitor as claimed in claim 1 is used.

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