Soybean protein peptide-based ternary composite scale inhibitor and application thereof

Abstract

The application discloses a kind of soy protein peptide-based ternary composite scale inhibitor and application thereof, belong to water treatment scale inhibition technical field.The scale inhibitor is composed of the following mass percentage components: soy protein peptide 10-25%, polyaspartic acid 1-7%, polyepoxysuccinic acid 3-10%, and the balance is deionized water;The weight average molecular weight of the soy protein peptide is 200-1000 Da, the weight average molecular weight of polyaspartic acid is 1000-5000 Da, and the weight average molecular weight of polyepoxysuccinic acid is 400-1500 Da.The application takes soy protein peptide as the core scale inhibition main body, polyaspartic acid and polyepoxysuccinic acid as auxiliary synergistic components, and the synergistic effect of ion chelation, lattice distortion and steric hindrance dispersion significantly improves the scale inhibition efficiency, and the calcium carbonate scale inhibition rate can reach more than 95%, and there is no phosphorus, biodegradable, with green environmental protection, broad-spectrum high efficiency, strong working condition adaptability and other advantages, suitable for industrial circulating cooling water, boiler water and oilfield water injection and other water treatment scenarios.

Description

Technical Field

[0001] This invention belongs to the field of water treatment scale inhibition technology, specifically relating to a soybean protein peptide-based ternary composite scale inhibitor and its application. Background Technology

[0002] In industrial production and daily life, calcium and magnesium ions in water easily combine with anions such as carbonate and sulfate to form insoluble deposits like calcium carbonate and calcium sulfate (i.e., scale). Scale adhering to the inner walls of pipes and equipment reduces heat transfer efficiency, increases energy consumption, and can even lead to pipe blockage, equipment corrosion, and shorten equipment lifespan, seriously affecting production safety and economic benefits. Therefore, scale inhibitors, as key agents in the water treatment field, are widely used in various water treatment scenarios.

[0003] Currently, most commonly used scale inhibitors in industry are chemically synthesized agents, such as organophosphorus and polyacrylic acid scale inhibitors. Although they have a certain scale inhibition effect, they have drawbacks such as poor biodegradability, easy eutrophication of water bodies, poor high-temperature stability, and easy secondary pollution, which do not conform to the development trend of green water treatment. To overcome these shortcomings, researchers have developed biodegradable green phosphorus-free scale inhibitors such as polyaspartic acid and polyepoxysuccinic acid. These scale inhibitors have good crystal distortion and dispersibility and have been applied in fields such as circulating cooling water treatment. However, when polyaspartic acid and polyepoxysuccinic acid are used alone, they both have weak scale inhibition specificity and low scale inhibition efficiency at low concentrations, which limits their effectiveness when used alone. To address the issue of poor performance of polyaspartic acid and polyepoxysuccinic acid when used alone, existing technologies have reported the use of compounding polyaspartic acid and polyepoxysuccinic acid for scale inhibition. For example, polyaspartic acid or polyepoxysuccinic acid is compounded with sodium gluconate to prepare scale and corrosion inhibitors, or modified polyaspartic acid or polyepoxysuccinic acid is compounded with polyacrylic acid for scale inhibition in geothermal fluids. However, these compounding schemes are mostly limited to binary compounding between polyaspartic acid and polyepoxysuccinic acid, or compounding with other synthetic polymers, resulting in limited scale inhibition effects.

[0004] On the other hand, scale inhibitors derived from natural biomass have attracted attention due to their environmentally friendly, non-toxic, and biodegradable characteristics. CN87107674A discloses a scale inhibitor with cereal protein or its partial degradation products as active ingredients. The weight average molecular weight of the active ingredient is above 700, and it can be used to prevent and inhibit various types of scale in high-temperature and low-temperature water systems. The cereal protein can be wheat gluten, corn gluten, or soybean protein. This technical solution proves the feasibility of cereal protein as a scale inhibitor. However, the application of cereal protein or its partial degradation products in this technology is relatively simple and does not involve its compound use with other scale inhibitors. In addition, soybean protein peptides, as enzymatic hydrolysis products of soybean protein, are rich in functional groups such as carboxyl (-COOH), amino (-NH2), and hydroxyl (-OH) in their molecular structure. They can form stable chelates with metal ions such as calcium and zinc through coordination bonds. Existing studies have shown that the carboxyl and amino groups in soybean peptides are the main coordination sites for metal ions. However, current research on soybean protein peptides is mostly focused on food nutrition and mineral supplements, and its application in water treatment scale inhibition is still lacking. It is worth noting that even though soybean protein peptides possess the aforementioned chelation and scale inhibition potential, their long-term microcrystalline dispersion and mineralization resistance are still insufficient under extreme water conditions of high salinity and high temperature. This makes it difficult to continuously and stably suspend fine scale particles, limiting their application as a scale inhibitor under harsh operating conditions. Summary of the Invention

[0005] To address the shortcomings of existing scale inhibitors, such as insufficient environmental friendliness, limited single-agent efficacy, and a lack of application of bio-based materials, this invention provides a soybean protein peptide-based ternary composite scale inhibitor. This scale inhibitor uses soybean protein peptides as the core scale inhibitor, and is compounded with small amounts of polyaspartic acid and polyepoxysuccinic acid as auxiliary synergistic components. This simplifies the preparation process, reduces costs, and through the synergistic effect of the three components, significantly improves scale inhibition efficiency, high-temperature stability, and water quality adaptability, resulting in a green, efficient, and widely applicable composite scale inhibitor.

[0006] The soybean protein peptide-based ternary composite scale inhibitor provided by the present invention is composed of the following components by mass percentage: 10%–25% soybean protein peptide, 1%–7% polyaspartic acid, 3%–10% polyepoxysuccinic acid, and the balance being deionized water.

[0007] Furthermore, the preferred soybean protein peptide-based ternary composite scale inhibitor is composed of the following components in weight percentage: 15%–21% soybean protein peptide, 2%–6% polyaspartic acid, 5%–7% polyepoxysuccinic acid, and the balance being deionized water.

[0008] Furthermore, the soybean protein peptides are prepared using an enzymatic hydrolysis process, with a weight-average molecular weight of 200–1000 Da, short molecular chains, and stable chemical properties. They do not precipitate within a pH range of 2.0–12.0, are heat-resistant (≤220℃), and form stable complexes with calcium, magnesium, and iron ions through carboxyl and amino groups, while simultaneously disrupting the growth trend of scale crystals, thus exhibiting both scale inhibition and mild corrosion inhibition effects.

[0009] Furthermore, the weight-average molecular weight of the polyaspartic acid is 1000–5000 Da.

[0010] Furthermore, the weight-average molecular weight of the polyepoxysuccinic acid is 400–1500 Da.

[0011] The preparation method of the soybean protein peptide-based ternary composite scale inhibitor provided by the present invention is as follows: according to the mass percentage composition of the scale inhibitor, weigh soybean protein peptide powder, polyaspartic acid, polyepoxysuccinic acid, and deionized water; add soybean protein peptide powder to deionized water and stir until the soybean protein peptide is completely dissolved, and the system is a uniform transparent or light yellow liquid; then add polyaspartic acid and polyepoxysuccinic acid, stir and mix evenly, and fill, seal and store.

[0012] This invention also provides the application of the soybean protein peptide-based ternary composite scale inhibitor in the scale inhibition treatment of industrial circulating cooling water, reverse osmosis water treatment, boiler feedwater, and high-hardness industrial wastewater.

[0013] Furthermore, when using the scale inhibitor of the present invention, the dosage is adjusted according to the hardness of the water to be treated: when the water hardness is <300mg / L (calculated as CaCO3), the dosage is 0.5-1mL / L; when the water hardness is 300-500mg / L (calculated as CaCO3), the dosage is 1-2mL / L.

[0014] In this invention, soybean protein peptides serve as the core scale inhibitor. These peptides are small-molecule polypeptides with a dense array of polar active functional groups, including amino, carboxyl, and hydroxyl groups. Their small particle size and outstanding interfacial adsorption activity make them key functional components for ion chelation, crystal nucleus inhibition, and lattice disruption. They preferentially bind to calcium and magnesium scale-forming ions in water, reducing the concentration of free scale-forming ions at the source; they preferentially occupy active sites for calcium carbonate crystal nucleus growth, inhibiting crystal nucleus germination and continuous crystal growth; they can also penetrate into the crystal lattice, creating lattice defects and disrupting the dense and regular calcite structure of calcium carbonate, making the scale loose and easy to detach; simultaneously, they form an organic adsorption protective film on the surface of the heat exchange metal substrate, achieving both scale inhibition and equipment corrosion inhibition. Polyaspartic acid and polyepoxysuccinic acid are used as auxiliary agents to specifically address the shortcomings of soybean protein peptides. Polyaspartic acid contains a large number of carboxyl groups in its molecular chain, which helps to chelate residual free calcium and magnesium ions, further distorting the calcium carbonate crystal form and promoting the transformation of hard calcite into loose spheroidalite, thus enhancing the crystal form modification ability of soybean protein peptides. However, polyaspartic acid itself has insufficient microcrystalline dispersion stability and cannot be used as the main scale inhibitor. Polyepoxysuccinic acid has excellent temperature resistance, acid and alkali resistance, and high salt resistance. It disperses fine scale crystals by relying on electrostatic repulsion and steric hindrance, avoiding microcrystalline agglomeration and sedimentation, and mainly addresses the shortcoming of long-term dispersion of soybean protein peptides. However, its calcium ion chelation and lattice destruction capabilities are weak, and the scale inhibition effect of calcium carbonate alone is poor. The three-component compound system uses the scale inhibition mechanism of soybean protein peptides as its core framework. Polyaspartic acid and polyepoxysuccinic acid provide functional supplementation to address the performance defects of the main components. This system establishes a hierarchical and synergistic scale inhibition system in which soybean protein peptides control the formation of crystal nuclei and lattice destruction, polyaspartic acid assists in chelating ions and modifying crystal forms, and polyepoxysuccinic acid provides long-term dispersion of microcrystals. Soybean protein peptides complete the most critical scale inhibition processes of crystal nucleus inhibition, ion chelation, and lattice distortion. Polyaspartic acid assists in complexing excess scale-forming ions and deepening the crystal distortion effect. Polyepoxysuccinic acid relies on steric hindrance to stably disperse the fine crystal particles broken by soybean protein peptides, preventing secondary agglomeration and deposition. After compounding, the system relies on the main component, soybean protein peptide, to dominate the overall charge distribution. It forms a nested spatial structure of small and large molecules with polyaspartic acid and polyepoxysuccinic acid. The small molecule soybean protein peptide is interspersed in the gaps between the polymer chains of polyaspartic acid and polyepoxysuccinic acid, which not only increases the negative charge density of the overall system and strengthens the steric barrier, but also reduces the adsorption resistance of the two synthetic aids on crystal and metal surfaces, thereby improving the adsorption efficiency and stability of polyaspartic acid and polyepoxysuccinic acid. On the basis of the core scale inhibition effect of soybean protein peptide, the two aids make up for the shortcomings in dispersion and temperature resistance. The three complement each other, effectively broadening the water quality range for which the agent is applicable and improving the overall scale inhibition performance of the compound system under harsh conditions such as high salinity and high temperature.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The entire process is green and environmentally friendly, and biodegradable. The scale inhibitor of this invention is free of phosphorus, nitrogen, heavy metals, and other toxic and harmful components. Soy protein peptides are natural bio-based materials with a biodegradability rate of ≥85%. Polyaspartic acid and polyepoxysuccinic acid are both biodegradable green scale inhibitors. Compared with traditional phosphorus-containing scale inhibitors, this invention eliminates the environmental pollution risk of eutrophication of water bodies from the source, which meets the requirements of environmental protection regulations and the development trend of green water treatment.

[0017] (2) Significant synergistic effect and excellent scale inhibition performance. This invention uses soybean protein peptides as the main scale inhibition core, and polyaspartic acid and polyepoxysuccinic acid as auxiliary synergistic components. The three components form a hierarchical synergistic scale inhibition system through the synergistic effect of multiple mechanisms such as ion chelation, lattice distortion, crystal form transformation and steric hindrance dispersion. At the same dosage concentration, the scale inhibition effect of the ternary compound system is significantly better than that of any single component and the polyaspartic acid / polyepoxysuccinic acid binary compound system, producing a significant synergistic effect. Among them, soybean protein peptides supplement chelation activity, polyaspartic acid mainly targets calcium and magnesium scale, and polyepoxysuccinic acid covers silica scale. The compound system has the comprehensive advantages of broad-spectrum scale inhibition, high hardness and high salt resistance, high temperature resistance and wide pH range.

[0018] (3) Strong adaptability to working conditions and wide range of applications. The scale inhibitor of this invention is suitable for a wide temperature range of 20-90℃ and a wide pH range of 6.0-9.0. It is compatible with membrane systems and metal pipelines, and leaves no residue or corrosion. The dosage under normal working conditions is 0.5-2 mL / L. The dosage should be adjusted according to the hardness of the water (0.5-1 mL / L when the hardness is <300 mg / L; 1-2 mL / L when the hardness is 300-500 mg / L). This scale inhibitor is mainly used to solve the technical problem of scale deposition in various water systems. It is especially suitable for industrial circulating cooling water, reverse osmosis water treatment, boiler feedwater, and high-hardness industrial wastewater. It can be widely used in various water scenarios requiring scale treatment in industries such as chemical, power, metallurgy, and oil extraction. It can effectively inhibit the formation and deposition of common scale such as calcium carbonate and calcium sulfate in water, protect the inner walls of pipelines and equipment, ensure the stable and efficient operation of related systems, and reduce production energy consumption and equipment maintenance costs.

[0019] (4) Excellent compatibility and good stability. The present invention optimizes the ratio of soybean protein peptides with polyaspartic acid and polyepoxysuccinic acid. There is no antagonistic effect between the components, and the compatibility is good. It does not separate, precipitate, or degrade under normal temperature and high temperature conditions. It has excellent storage stability and can directly replace traditional scale inhibitors.

[0020] (5) Raw materials are readily available, low in cost, simple in process, and highly suitable for industrialization. Soybean protein peptides are deep-processed products of agricultural by-products, with a wide range of raw material sources and low prices; polyaspartic acid and polyepoxysuccinic acid are green water treatment agents that can be mass-produced on a large scale, with a mature supply chain. The combination of the three does not require expensive modified raw materials, and the preparation process is carried out at room temperature and pressure without heating, catalysis, or reaction modification. The process is extremely simple and energy consumption is extremely low. The overall cost is significantly lower than that of imported high-end phosphorus-free scale inhibitors and artificially synthesized polypeptide agents, giving it strong industrialization promotion value and market competitiveness. Attached Figure Description

[0021] Figure 1 This is a diagram showing the scale buildup on the silicon wafer surface after a scale inhibition test without the addition of scale inhibitor.

[0022] Figure 2 This is a diagram showing the scale buildup on the silicon wafer surface after the scale inhibition test of the scale inhibitor in Example 1.

[0023] Figure 3 This is a SEM image taken after the scale inhibition test without adding scale inhibitor.

[0024] Figure 4 This is a SEM image taken after the scale inhibition test of the scale inhibitor in Example 1 was completed. Detailed Implementation

[0025] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these existing embodiments.

[0026] Example 1

[0027] Add 300g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, and stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 30g of polyaspartic acid with a weight average molecular weight of 1000-5000 Da and 70g of polyepoxysuccinic acid with a weight average molecular weight of 400-1500 Da, and stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0028] Example 2

[0029] Add 260g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, and stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 50g of polyaspartic acid with a weight average molecular weight of 1000-5000 Da and 90g of polyepoxysuccinic acid with a weight average molecular weight of 400-1500 Da, and stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0030] Example 3

[0031] Add 220g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, and stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 80g of polyaspartic acid with a weight average molecular weight of 1000-5000 Da and 100g of polyepoxysuccinic acid with a weight average molecular weight of 400-1500 Da, and stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0032] Comparative Example 1

[0033] Add 400g of soybean protein peptides with a molecular weight of 200-1000 Da to 1000g of deionized water and stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved. The system is a uniform transparent or light yellow liquid, which is used to prepare a single scale inhibitor.

[0034] Comparative Example 2

[0035] Add 300g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 100g of polyaspartic acid with a weight average molecular weight of 1000-5000 Da, stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0036] Comparative Example 3

[0037] Add 220g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 180g of polyaspartic acid with a weight average molecular weight of 1000-5000 Da, stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0038] Comparative Example 4

[0039] Add 300g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 100g of polyepoxysuccinic acid with a weight average molecular weight of 400-1500 Da, stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0040] Comparative Example 5

[0041] Add 220g of soybean protein peptides with a weight average molecular weight of 200-1000 Da to 1000g of deionized water, stir at room temperature and 250r / min until the soybean protein peptides are completely dissolved and the system is a uniform transparent or light yellow liquid. Then add 180g of polyepoxysuccinic acid with a weight average molecular weight of 400-1500 Da, stir at room temperature and 400r / min until uniformly mixed to obtain the compound scale inhibitor product.

[0042] Comparative Example 6

[0043] Add 200g of polyaspartic acid with a weight average molecular weight of 200-1000 Da and 200g of polyepoxysuccinic acid with a weight average molecular weight of 400-1500 Da to 1000g of deionized water, and stir and mix evenly at room temperature and 400 r / min to obtain the compound scale inhibitor product.

[0044] According to GB / T16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method", the scale inhibitors obtained in Examples 1-3 and Comparative Examples 1-6 were subjected to calcium carbonate scale inhibition experiments. 2+ Concentration of 240 mg / L, CO3 2- A scale inhibitor was added to an aqueous solution with a concentration of 672 mg / L at a dosage of 0.5 mL / L; the test results are shown in Table 1.

[0045] Table 1

[0046]

[0047] Table 1 shows that there are significant differences in the calcium carbonate scale inhibition rate of different scale inhibitors under the same test conditions: the calcium carbonate scale inhibition rates of Examples 1-3 all remained at a high level of over 90%. Among them, Example 1 showed the best scale inhibition effect, reaching 95.36%. Comparative Example 1 was a single soybean protein peptide scale inhibitor, with a calcium carbonate scale inhibition rate of 81.73%. Although it had a certain scale inhibition effect, it was significantly lower than the effect of the ternary compound system in Examples 1-3, indicating that the scale inhibition performance of soybean protein peptide alone is limited. Comparative Examples 2 and 3 did not add polyepoxysuccinic acid, and the calcium carbonate scale inhibition rates were 75.18% and 65.42%, respectively, both lower than the ternary compound system of Examples 1-3 with the same total effective component content. It is noteworthy that when the proportion of polyaspartic acid increased from 7% to 13%, the scale inhibition rate actually decreased from 75.18% to 65.42%, indicating that there is an optimal ratio range for the binary blend of soybean protein peptides and polyaspartic acid. Excessive addition of polyaspartic acid dilutes the scale inhibition contribution of soybean protein peptides, which is detrimental to the overall scale inhibition performance of the system. In Comparative Examples 4 and 5, without the addition of polyaspartic acid, the calcium carbonate scale inhibition rates were 78.69% and 70.13%, respectively, which were also lower than the ternary blend systems of Examples 1-3. Similar to Comparative Examples 2-3, when the proportion of polyepoxysuccinic acid increased from 7% to 13%, the scale inhibition rate decreased, further demonstrating the limitations of the binary blend system. Comparative Example 6 is a binary compound of polyaspartic acid and polyepoxysuccinic acid, which does not contain soy protein peptides. Its calcium carbonate scale inhibition rate is only 45.24%, which is much lower than all other scale inhibitor formulations containing soy protein peptides. This indicates that the scale inhibition effect of the binary compound system of polyaspartic acid and polyepoxysuccinic acid is extremely limited when there are no soy protein peptides as the core scale inhibitor.

[0048] The above scale inhibition rate data indicate that the ternary compound system of this invention, with soybean protein peptide as the core scale inhibitor and polyaspartic acid and polyepoxysuccinic acid as auxiliary synergistic components, exhibits a significant synergistic effect among the three components. Soybean protein peptide provides the core chelating and lattice disruption functions, while polyaspartic acid and polyepoxysuccinic acid provide auxiliary synergistic effects through crystal distortion and microcrystal dispersion, respectively. The synergistic effect of these three components makes the scale inhibition effect of the ternary compound system significantly superior to that of any single component or binary compound system, fully demonstrating the superiority and irreplaceability of the ternary compound system of this invention in terms of scale inhibition performance.

[0049] Further observation was conducted on the scale morphology on the silicon wafer surface after the scale inhibition test. Under the same water quality, temperature, and experimental duration conditions, the blank control group without scale inhibitor was compared (…). Figure 1 This results in the formation of a dense, thick, and strongly adherent white scale layer on the silicon wafer surface, completely covering the smooth surface of the substrate. The experimental group with the scale inhibitor from Example 1 of this invention added ( Figure 2The amount of scale on the silicon wafer surface is significantly reduced, with no continuous scale film. Most of the surface remains clean, with only a small amount of loose and easily detachable deposits attached sporadically, indicating that the compound scale inhibitor of this invention has excellent scale inhibition performance.

[0050] The morphology of calcium carbonate crystals after the scale inhibition experiment was further observed using scanning electron microscopy (SEM). Without the addition of scale inhibitor ( Figure 3 Calcium carbonate crystals exhibit a regular cubic morphology, with smooth surfaces, sharp edges, and a dense and regular structure, typical of calcite crystals. After adding the scale inhibitor from Example 1 of this invention ( Figure 4 The size of calcium carbonate crystals is significantly reduced, the crystal edges tend to be rounded and blunt, the particles are loosely arranged, making it difficult to accumulate and form dense hard scale, and the crystal morphology is significantly distorted.

[0051] The aforementioned scale inhibition rate data and crystal morphology analysis results jointly demonstrate that the scale inhibitor of this invention can effectively embed itself within calcium carbonate crystals. The polar functional groups such as carboxyl, amino, and hydroxyl groups on its molecular chain form coordination bonds or hydrogen bonds with calcium ions or oxygen atoms on the crystal surface, inducing lattice distortion, interfering with the normal growth process of calcium carbonate crystals, inhibiting the preferred growth of calcite crystal faces, and promoting the transformation of dense calcite-type hard scale into loose scale. The significant reduction in macroscopic scale on the silicon wafer surface and the microscopic crystal distortion observed by SEM corroborate each other, jointly confirming the excellent scale inhibition performance of the scale inhibitor of this invention from both macroscopic and microscopic perspectives. The loose scale is easily detached and discharged with the water flow under the influence of water scouring and temperature fluctuations, thereby significantly improving the overall scale inhibition effect.

Claims

1. A soybean protein peptide-based ternary composite scale inhibitor, characterized in that, It consists of the following components by mass percentage: 10%–25% soybean protein peptides, 1%–7% polyaspartic acid, 3%–10% polyepoxysuccinic acid, and the balance being deionized water.

2. The soybean protein peptide-based ternary composite scale inhibitor according to claim 1, characterized in that, It consists of the following components by weight percentage: 15%–21% soybean protein peptides, 2%–6% polyaspartic acid, 5%–7% polyepoxysuccinic acid, and the balance being deionized water.

3. The soybean protein peptide-based ternary composite scale inhibitor according to claim 1, characterized in that, The weight-average molecular weight of the soybean protein peptides is 200–1000 Da.

4. The soybean protein peptide-based ternary composite scale inhibitor according to claim 1, characterized in that, The weight-average molecular weight of the polyaspartic acid is 1000–5000 Da.

5. The soybean protein peptide-based ternary composite scale inhibitor according to claim 1, characterized in that, The weight-average molecular weight of the polyepoxysuccinic acid is 400–1500 Da.

6. The application of the soybean protein peptide-based ternary composite scale inhibitor according to any one of claims 1 to 5 in the scale inhibition treatment of industrial circulating cooling water, reverse osmosis water treatment, boiler feedwater, and high-hardness industrial wastewater.

7. The application of the soybean protein peptide-based ternary composite scale inhibitor according to claim 6 in scale inhibition treatment of industrial circulating cooling water, boiler water, or oilfield injection water, characterized in that, The dosage of the scale inhibitor in the water to be treated is adjusted according to the water hardness: when the water hardness (calculated as CaCO3) is <300 mg / L, the dosage is 0.5 to 1 mL / L; when the water hardness (calculated as CaCO3) is 300 to 500 mg / L, the dosage is 1 to 2 mL / L.

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