Composite corrosion and scale inhibitor as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of corrosion and scale inhibitors, and relates to a composite corrosion and scale inhibitor as well as a preparation method and application thereof. The composite corrosion and scale inhibitor comprises the following components in percentage by weight: 10%-20% of a phosphorus compound, 25%-40% of a polycarboxylic acid composition, 2%-5% of an organic amine compound, 2%-5% of amino acid, 5%-10% of water-soluble inorganic metal salt and the balance of deionized water. The composite corrosion and scale inhibitor is relatively low in organophosphorus content, overcomes the defects of obvious critical threshold effect, high environmental toxicity and the like of a traditional single agent through a multi-component synergistic effect, and can be directly applied to a weakly acidic water body with the pH value smaller than 7.

Description

Technical Field

[0001] The present invention belongs to the technical field of corrosion and scale inhibitors, and relates to a composite corrosion and scale inhibitor, its preparation method and application, in particular to a composite corrosion and scale inhibitor applicable to industrial circulating cooling water systems, its preparation method and application. Background Art

[0002] Circulating cooling water systems provide refrigeration or cooling services for production process systems through the cyclic evaporation of water throughout the production process. During the use of circulating cooling water, continuous evaporation and concentration occur, and the dissolved salts are continuously concentrated, resulting in serious scaling and corrosion problems in the cooling water pipes, and it is easy to breed bacteria and algae, thus affecting the heat transfer effect of the equipment and shortening the service life of the equipment. To solve these problems, water quality treatment of circulating cooling water must be carried out.

[0003] Organic phosphonic acids are a type of water treatment agent widely used at present. They were developed in the mid-1960s abroad and recognized in the 1970s. They have good chemical stability, high temperature resistance, and also have characteristics such as low dosage, corrosion inhibition and scale inhibition effects. In addition, organic phosphonic acids have excellent chelating ability for many metal ions. They solve the problem of calcium carbonate scale formation in the system. The existence of C-P bonds makes their chemical properties stable and relatively high temperature resistant, with obvious "threshold effect" and "synergistic effect". However, organic phosphonic acids cannot effectively inhibit the formation of calcium phosphate scale, zinc scale and iron oxide deposition in phosphorous and phosphorous-zinc water treatment formulations. The discharge of phosphorus-containing wastewater will also cause eutrophication of water bodies and marine red tides. Foreign countries have implemented phosphorus restriction or phosphorus prohibition measures, and China also strongly advocates the development of low-phosphorus and phosphorus-free products. Copolymer scale inhibitors are a new type of water treatment agent developed after the 1980s. They have excellent performance, good compatibility, no phosphorus pollution, and broad development prospects. However, their price is high, and they cannot meet the water treatment needs when used alone, so other components need to be added for compound use. At the same time, when replenishing water with an alkalinity lower than 30 mg / L (calculated as calcium carbonate) in the circulating water, the pH of the naturally operating circulating water is generally less than 7.0. Most current water treatment formulations are alkaline. When treating weakly acidic water with a pH less than 7.0, it is generally necessary to add alkaline substances to the circulating water system to adjust the pH of the circulating water to above 7.5, and then use an alkaline water treatment formulation for treatment. This method not only consumes a large amount of alkali and has high costs, but also has high labor intensity and limited treatment effects.

[0004] CN101560022B discloses a compound corrosion and scale inhibitor, which is made from raw materials with a mass ratio of organic phosphonic acid, acrylic acid or acrylic acid copolymer, polymaleic acid, azole derivative, polyamine organic sulfonate, dimethylformamide or alcohol, and water. The compound corrosion and scale inhibitor of the invention is used in a system where reclaimed water is used as circulating cooling water, and can solve the corrosion caused by reclaimed circulating water to equipment. However, the phosphorus content in this compound corrosion and scale inhibitor is relatively high and the components are complex, and it is only applicable to the system where reclaimed water is used as circulating cooling water, so its application is limited. CN109110935A discloses a corrosion and scale inhibitor for low hardness and low alkalinity water and its preparation method. This formulation is a high-phosphorus formulation. In a low-salt water system, the concentration ratio is generally relatively high, and there is an enrichment of phosphorus content in the system. In addition, a certain amount of calcium ions in the water are required to participate in the film-forming reaction. CN101805067A discloses a phosphorus-free green compound corrosion and scale inhibitor, which contains polyaspartic acid or polyepoxysuccinic acid, maleic acid homopolymer, acrylic acid copolymer, inorganic zinc salt, ECH corrosion synergist and water. The phosphorus-free green compound corrosion and scale inhibitor is only applicable to treating alkaline water quality and not applicable to treating acidic water quality.

[0005] Therefore, there is a need for a compound corrosion and scale inhibitor with low phosphorus content that can be directly applied to weakly acidic water bodies with a pH less than 7. Summary of the Invention

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide a compound corrosion and scale inhibitor, its synthesis method and application. The organic phosphorus content of this compound corrosion and scale inhibitor is relatively low, and through the synergistic effect of multiple components, it solves the defects of obvious critical threshold effect and high environmental toxicity existing in traditional single agents, and can be directly applied to weakly acidic water bodies with a pH less than 7.

[0007] To achieve the above object, the present invention is realized through the following technical solutions.

[0008] A compound corrosion and scale inhibitor, by weight percentage, includes: 10%-20% of phosphorus compound, 25%-40% of polycarboxylic acid composition, 2%-5% of organic amine compound, 2%-5% of amino acid, 5-10% of water-soluble inorganic metal salt, and deionized water is added up to 100%.

[0009] Further, the phosphorus compound is an inorganic phosphorus compound and an organic phosphorus compound.

[0010] Further, the weight ratio of the inorganic phosphorus compound to the organic phosphorus compound is 0.1-0.4:1.

[0011] Further, the inorganic phosphorus compound is one or more combinations of phosphoric acid and its potassium salt, sodium salt, ammonium salt and aluminum salt.

[0012] Further, the organophosphorus compound contains at least one functional group among amino group, hydroxyl group, carboxyl group or ester group.

[0013] Further, the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer.

[0014] Further, the weight ratio of polyepoxysuccinic acid to sulfonate copolymer is 0.75 - 2:1.

[0015] Further, the sulfonate copolymer is one or a combination of more than one of acrylic acid / propylsulfonic acid copolymer, acrylic acid / 2 - acrylamido - 2 - methylpropanesulfonic acid copolymer, acrylic acid / 2 - hydroxy - 3 - allyloxy - 1 - propenesulfonic acid copolymer, acrylic acid / methylethylacrylic acid sulfonate copolymer, acrylic acid / propoxypolyethoxysulfonate copolymer, maleic anhydride / propoxypolyethoxysulfonate copolymer or acrylic acid / isoprene sulfonate / acrylic acid hydroxypropyl ester copolymer.

[0016] Further, the organic amine compound is one or a combination of more than one of ethanolamine, diethanolamine, triethanolamine, hexadecylamine, octadecylamine, dihexadecylamine, cyclohexylamine, aliphatic polyamine, aromatic polyamine or ammonium dodecyl sulfate.

[0017] Further, the amino acid is one or a combination of more than one of glycine, tryptophan, alanine or arginine.

[0018] Further, the water - soluble inorganic metal salt is zinc salt, sodium salt, potassium salt or calcium salt.

[0019] A preparation method of a composite corrosion and scale inhibitor includes the following steps: Step 1: Dissolve the phosphorus compound in deionized water at 40 - 50 °C to obtain mixed solution 1; Step 2: Add the polycarboxylic acid composition to mixed solution 1, stir and mix for 30 - 60 min to obtain mixed solution 2; Step 3: Sequentially add the organic amine compound, amino acid and water - soluble inorganic metal salt to mixed solution 2, and adjust the solution pH to 8 - 10 to obtain mixed solution 3; Step 4: Filter mixed solution 3 to obtain a light yellow transparent liquid, which is the composite corrosion and scale inhibitor.

[0020] This composite corrosion and scale inhibitor is applicable to industrial circulating cooling water systems.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0022] 1. The composite corrosion and scale inhibitor prepared by the present invention from a phosphorus compound, a polycarboxylic acid composition, an organic amine compound, an amino acid, a water-soluble inorganic metal salt and deionized water can be effectively applied to various industrial circulating cooling water systems, effectively inhibit the formation of scale, and has prominent anti-corrosion performance. It can effectively improve the heat transfer efficiency of equipment, reduce energy consumption, and reduce equipment failures and maintenance frequencies caused by scaling.

[0023] 2. Based on the system of the present invention, an inorganic phosphorus compound and an organic phosphorus compound are used in combination. When an organic phosphorus-containing corrosion and scale inhibitor and a low molecular weight polyelectrolyte are used in combination, a synergistic effect of the agents will occur, thereby improving the corrosion and scale inhibition effect of the agents; the addition of the inorganic phosphorus compound effectively improves the chelating and dispersing effects of the organic phosphorus compound, more efficiently forms stable soluble chelates with scale-forming ions such as calcium and magnesium in water, increases the solubility of calcium and magnesium salts, inhibits the formation of scale, and interferes with the crystallization process of inorganic salts, resulting in lattice distortion, so that crystal nuclei or crystal particles cannot grow according to the normal lattice arrangement, and thus are dispersed in water, slowing down the scaling rate. At the same time, the organic phosphorus content is much lower than that of commercially available conventional corrosion and scale inhibitors, which helps to reduce environmental pollution and production costs.

[0024] 3. Based on the system of the present invention, by using the phosphorus compound and the polycarboxylic acid composition in combination, the scale inhibition efficiency is effectively improved and the corrosion inhibition effect is enhanced. The phosphorus compound can form stable soluble chelates with scale-forming ions such as calcium and magnesium in water, increasing the solubility of these metal ions. The polycarboxylic acid scale inhibitor forms a water-soluble complex or chelate with calcium ions through the negatively charged molecular chain generated by ionization, further increasing the solubility of scale-forming compounds. At the same time, both the phosphorus compound and the polycarboxylic acid composition can adsorb around crystal nuclei or crystal particles at the beginning of the formation of scale salts, making them unable to grow according to the normal lattice arrangement, and thus being dispersed in water. This lattice distortion effect effectively prevents the formation of scale. The combination of the two plays a synergistic role, significantly enhancing this chelating effect and lattice distortion effect, and having a wider range of action.

[0025] 4. Based on the system of the present invention, an organic amine compound and an amino acid are used in combination. Polar groups exist in both the organic amine compound and the amino acid molecules. They are firmly attached to the metal surface through electrostatic adsorption or van der Waals forces to form a protective film to isolate the metal from the corrosive medium, thereby inhibiting the corrosion reaction. The synergistic effect of their combination significantly enhances the corrosion inhibition effect. At the same time, the addition of the strongly basic organic amine compound enables the composite corrosion and scale inhibitor to still maintain excellent performance in a weak acid environment and can be directly applied to weakly acidic water bodies with a pH less than 7.

[0026] 5. Based on the system of the present invention, by adding water-soluble inorganic metal salts, a protective film can be formed on the metal surface to isolate the metal from contact with corrosive media (such as oxygen, acid and base ions), thereby significantly slowing down the corrosion rate. At the same time, the addition of water-soluble inorganic metal salts synergistically combines with the polycarboxylic acid composition in terms of chelation, solubilization and solubility improvement, lattice distortion and fouling layer structure optimization, and complementary corrosion inhibition. After the inorganic metal salt combines with the polycarboxylic acid substance, a more stable complex can be formed. This complex can more effectively bind metal ions and prevent them from reacting with anions to form scale, thus significantly improving the scale inhibition effect and enhancing the corrosion inhibition performance of the system; the polycarboxylic acid composition generates a negatively charged molecular chain through ionization, increasing the solubility of scale-forming compounds. This solubilization effect synergistically combines with the complexation effect of the inorganic metal salt to further reduce the precipitation tendency of scale; after the inorganic metal salt combines with the polycarboxylic acid composition, the polymer chain can be more evenly adsorbed on the surface of the fouling layer, interfering with the normal growth of crystal grains and making them smooth and soft. This lattice distortion effect significantly improves the fluidity of the fouling layer, making it easy to be washed away by water flow, thereby enhancing the scale inhibition performance; both water-soluble inorganic metal salts and polycarboxylic acid compositions reduce the activity of metal ions through complexation reactions, reducing the corrosion risk. The synergistic effect of the two can more comprehensively protect metal equipment and extend its service life.

[0027] 6. Based on the system of the present invention, through the combination of inorganic phosphorus compounds and inorganic metal salts, their synergistic effect is reflected in that they can jointly act on the scale-forming ions in water. By forming stable complexes and precipitates, the formation of scale is reduced, and at the same time, the corrosion of the metal surface is prevented. This synergistic effect not only improves the scale inhibition efficiency of the corrosion inhibitor and scale inhibitor but also enhances its corrosion inhibition performance, thereby effectively protecting metal equipment from corrosion. At the same time, the combination of specific inorganic phosphorus compounds and inorganic metal salts effectively improves the stability of the system, so that the composite corrosion inhibitor and scale inhibitor will not or rarely precipitate and delaminate after long-term storage.

[0028] In summary, this composite corrosion inhibitor and scale inhibitor still maintains excellent performance in a weak acid environment and can be directly applied to weakly acidic water bodies with a pH less than 7. Detailed implementation manners

[0029] To facilitate the understanding of the present invention, the technical solutions of the present invention will be comprehensively described below in conjunction with specific implementation manners. However, the following described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0030] A composite corrosion and scale inhibitor, by weight percentage, includes: 10%-20% of phosphorus compound, 25%-40% of polycarboxylic acid composition, 2%-5% of organic amine compound, 2%-5% of amino acid, 5-10% of water-soluble inorganic metal salt, and deionized water to make up 100%.

[0031] In this embodiment, the phosphine compound is an inorganic phosphorus compound and an organic phosphorus compound.

[0032] In this embodiment, the weight ratio of the inorganic phosphorus compound to the organic phosphorus compound is 0.1-0.4:1; preferably, the weight ratio of the inorganic phosphorus compound to the organic phosphorus compound is 0.2-0.25:1.

[0033] In this embodiment, the inorganic phosphorus compound is one or a combination of phosphoric acid and its potassium salt, sodium salt, ammonium salt, and aluminum salt; preferably, the inorganic phosphorus compound is one or a combination of potassium dihydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and disodium hydrogen phosphate.

[0034] In this embodiment, the organic phosphine compound contains at least one functional group among amino group, hydroxyl group, carboxyl group, or ester group; preferably, the organic phosphine compound is hydroxyethylidene diphosphonic acid, 2-hydroxyphosphonoacetic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, diethylenetriaminepenta(methylene phosphonic acid), 2-phosphonobutane-1,2,4-tricarboxylic acid, polyamino polyether methylene phosphonic acid, bis(1,6-hexylene triamine pentamethylene phosphonic acid), and their potassium salts, sodium salts, ammonium salts, aluminum salts, as well as one or a combination of polyol phosphate and polyether alcohol amine phosphate.

[0035] In this embodiment, the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer.

[0036] In this embodiment, the weight ratio of polyepoxysuccinic acid to sulfonate copolymer is 0.75-2:1; preferably, the weight ratio of polyepoxysuccinic acid to sulfonate copolymer is 1-1.5:1.

[0037] In this embodiment, the sulfonate copolymer is one or a combination of acrylic acid / propylsulfonic acid copolymer, acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, acrylic acid / 2-hydroxy-3-allyloxy-1-propenesulfonic acid copolymer, acrylic acid / methylethylacrylic acid sulfonate copolymer, acrylic acid / propoxy polyethoxy sulfonate copolymer, maleic anhydride / propoxy polyethoxy sulfonate copolymer, or acrylic acid / isoprene sulfonate / acrylic acid hydroxypropyl ester copolymer; preferably, the sulfonate copolymer is acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the molar ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid is 2.5-3.5:1.

[0038] In this embodiment, the organic amine compound is one or a combination of more than one of ethanolamine, diethanolamine, triethanolamine, hexadecylamine, octadecylamine, dihexadecylamine, cyclohexylamine, aliphatic polyamine, aromatic polyamine, or ammonium dodecyl sulfate; preferably, the organic amine compound is ethanolamine.

[0039] In this embodiment, the amino acid is one or a combination of more than one of glycine, tryptophan, alanine, or arginine; preferably, the amino acid is glycine.

[0040] In this embodiment, the water-soluble inorganic metal salt is a zinc salt, sodium salt, potassium salt, or calcium salt; preferably, the water-soluble inorganic metal salt is one or a combination of more than one of zinc nitrate, zinc sulfate, zinc chloride, sodium chloride, sodium sulfate, sodium nitrate, sodium dihydrogen phosphate, or disodium hydrogen phosphate; more preferably, the water-soluble inorganic metal salt is a mixture of zinc sulfate and sodium chloride, and the mass ratio of zinc sulfate to sodium chloride is 4-6:1.

[0041] A preparation method of a composite corrosion and scale inhibitor includes the following steps: Step 1: Dissolve the phosphorus compound in deionized water at 40-50 °C to obtain a mixed solution 1; Step 2: Add the polycarboxylic acid composition to the mixed solution 1 and stir and mix for 30-60 min to obtain a mixed solution 2; Step 3: Sequentially add the organic amine compound, amino acid, and water-soluble inorganic metal salt to the mixed solution 2, and adjust the solution pH to 8-10 to obtain a mixed solution 3; Step 4: Filter the mixed solution 3 to obtain a light yellow transparent liquid, which is the composite corrosion and scale inhibitor.

[0042] Example 1.

[0043] A composite corrosion and scale inhibitor includes, by weight percentage: 18% of phosphorus compound, 35% of polycarboxylic acid composition, 5% of organic amine compound, 3% of amino acid, 10% of water-soluble inorganic metal salt, and deionized water is added to make up to 100%.

[0044] Among them, the phosphorus compound is a combination of sodium dihydrogen phosphate and hydroxyethane diphosphonic acid, and the mass ratio of sodium dihydrogen phosphate to hydroxyethane diphosphonic acid is 0.25:1; the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer, and the mass ratio of polyepoxysuccinic acid to sulfonate copolymer is 1.5:1. The sulfonate copolymer is an acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the molar ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid is 3:1; the organic amine compound is ethanolamine; the amino acid is glycine; the water-soluble inorganic metal salt is a mixture of zinc sulfate and sodium chloride, and the mass ratio of zinc sulfate to sodium chloride is 4:1.

[0045] The preparation of the composite corrosion and scale inhibitor includes the following steps: (1) Dissolve sodium dihydrogen phosphate and 1-hydroxyethylidene-1,1-diphosphonic acid in deionized water at 40 - 50 °C; (2) Add polyepoxysuccinic acid and sulfonate copolymer in sequence, and stir and mix for about 30 min; (3) Add ethanolamine, glycine, zinc sulfate and sodium chloride, and adjust the pH to 8.5 - 9.5; (4) Filter to obtain a light yellow transparent liquid, namely the composite corrosion and scale inhibitor.

[0046] Example 2.

[0047] A composite corrosion and scale inhibitor includes, by weight percentage: 15% of phosphorus compound, 35% of polycarboxylic acid composition, 5% of organic amine compound, 3% of amino acid, 10% of water-soluble inorganic metal salt, and deionized water is added up to 100%.

[0048] Among them, the phosphorus compound is a combination of sodium dihydrogen phosphate and aminotrimethylenephosphonic acid, and the mass ratio of sodium dihydrogen phosphate to aminotrimethylenephosphonic acid is 0.25:1; the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer, and the mass ratio of polyepoxysuccinic acid to sulfonate copolymer is 1.5:1. The sulfonate copolymer is an acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the molar ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid is 3:1; the organic amine compound is ethanolamine; the water-soluble inorganic metal salt is a mixture of zinc sulfate and sodium chloride, and the mass ratio of zinc sulfate to sodium chloride is 4:1.

[0049] Refer to the preparation method in Example 1 to prepare the composite corrosion and scale inhibitor.

[0050] Example 3.

[0051] A composite corrosion and scale inhibitor includes, by weight percentage: 18% of phosphorus compound, 30% of polycarboxylic acid composition, 5% of organic amine compound, 3% of amino acid, 10% of water-soluble inorganic metal salt, and deionized water is added up to 100%.

[0052] Among them, the phosphorus compound is a combination of sodium dihydrogen phosphate and 1-hydroxyethylidene-1,1-diphosphonic acid, and the mass ratio of sodium dihydrogen phosphate to 1-hydroxyethylidene-1,1-diphosphonic acid is 0.25:1; the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer, and the mass ratio of polyepoxysuccinic acid to sulfonate copolymer is 1.5:1. The sulfonate copolymer is an acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the molar ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid is 3:1; the amino acid is glycine; the water-soluble inorganic metal salt is a mixture of zinc sulfate and sodium chloride, and the mass ratio of zinc sulfate to sodium chloride is 4:1.

[0053] Refer to the preparation method in Example 1 to prepare the composite corrosion and scale inhibitor.

[0054] Example 4

[0055] A composite corrosion and scale inhibitor, by weight percentage, includes: 18% phosphorus compound, 35% polycarboxylic acid composition, 2% organic amine compound, 3% amino acid, 10% water-soluble inorganic metal salt, and deionized water is added up to 100%.

[0056] Among them, the phosphorus compound is a combination of sodium dihydrogen phosphate and hydroxyethane diphosphonic acid, and the mass ratio of sodium dihydrogen phosphate to hydroxyethane diphosphonic acid is 0.25:1; the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer, and the mass ratio of polyepoxysuccinic acid to sulfonate copolymer is 1.5:1; the sulfonate copolymer is an acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the molar ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid is 3:1; the organic amine compound is ethanolamine; the amino acid is glycine; the water-soluble inorganic metal salt is a mixture of zinc sulfate and sodium chloride, and the mass ratio of zinc sulfate to sodium chloride is 4:1.

[0057] Refer to the preparation method in Example 1 to prepare the composite corrosion and scale inhibitor.

[0058] Example 5

[0059] A composite corrosion and scale inhibitor, by weight percentage, includes: 18% phosphorus compound, 35% polycarboxylic acid composition, 5% organic amine compound, 3% amino acid, 6% water-soluble inorganic metal salt, and deionized water is added up to 100%.

[0060] Among them, the phosphorus compound is a combination of sodium dihydrogen phosphate and hydroxyethane diphosphonic acid, and the mass ratio of sodium dihydrogen phosphate to hydroxyethane diphosphonic acid is 0.25:1; the polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer, and the mass ratio of polyepoxysuccinic acid to sulfonate copolymer is 1.5:1, the sulfonate copolymer is an acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the molar ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid is 3:1; the organic amine compound is ethanolamine; the amino acid is glycine; the water-soluble inorganic metal salt is a mixture of zinc sulfate and sodium chloride, and the mass ratio of zinc sulfate to sodium chloride is 4:1.

[0061] Refer to the preparation method in Example 1 to prepare the composite corrosion and scale inhibitor.

[0062] Comparative Example 1 According to the method of Example 1, the difference is that hydroxyethane diphosphonic acid is not added.

[0063] Comparative Example 2 According to the method of Example 1, the difference is that sodium dihydrogen phosphate is not added.

[0064] Comparative Example 3 According to the method of Example 1, except that polyepoxysuccinic acid is not added.

[0065] Comparative Example 4 According to the method of Example 1, except that sulfonate copolymer is not added.

[0066] Comparative Example 5 According to the method of Example 1, except that organic amine compound is not added.

[0067] Comparative Example 6 According to the method of Example 1, except that zinc sulfate is not added.

[0068] Performance test: The observation results of the apparent phenomena of the composite corrosion and scale inhibitors prepared in Examples 1-5 and Comparative Examples 1-6 are shown in Table 1.

[0069] Table 1 Apparent phenomena of the composite corrosion and scale inhibitors.

[0070] It can be seen from the results in Table 1 that the composite corrosion and scale inhibitor with clear and transparent appearance and stable state can be prepared by the method of the present invention.

[0071] Using laboratory tap water as the test water, the corrosion inhibition performance and scale inhibition performance of the composite corrosion and scale inhibitors in Examples 1-5 and Comparative Examples 1-6 were evaluated. The laboratory tap water was adjusted to weakly acidic by adding HCl. The specific water quality data are shown in Table 2. The evaluation test methods refer to GB / T 18175-2014 (corrosion inhibition performance) and GB / T 16632-2019 (scale inhibition performance).

[0072] Table 2 Laboratory tap water data.

[0073] The evaluation test results of the composite corrosion and scale inhibitors prepared in Examples 1-5 and Comparative Examples 1-6 are shown in Table 3.

[0074] Table 3 Evaluation test results of the composite corrosion and scale inhibitors.

[0075] As can be seen from Table 3, the composite corrosion and scale inhibitors prepared in Examples 1-5 all have relatively low corrosion rates and relatively high scale inhibition rates. The corrosion rates are all lower than 0.030 mm / a, and the scale inhibition rates are all higher than 99%. Among them, the data of Example 1 are better than those of other examples. The corrosion rate is the lowest, 0.012 mm / a, and the scale inhibition rate is the highest, 99.6%. The corrosion rates of Example 2 and Example 3 are relatively high, exceeding 0.020 mm / a. The scale inhibition rates of Example 2 and Example 5 are relatively low, 99.2%. The corrosion rates of the composite corrosion and scale inhibitors prepared in Comparative Examples 1-6 are all much higher than those of each example, and at the same time, the scale inhibition rates are all much lower than those of each example.

[0076] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention. In addition, any combination can be made among various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A composite corrosion and scale inhibitor, characterized in that, Comprising by weight percentage: 10%-20% of phosphorus compound, 25%-40% of polycarboxylic acid composition, 2%-5% of organic amine compound, 2%-5% of amino acid, 5-10% of water-soluble inorganic metal salt, and deionized water to make up 100%.

2. The composite corrosion inhibitor and scale inhibitor according to claim 1, wherein The phosphine compound is an inorganic phosphorus compound and an organic phosphorus compound; the weight ratio of the inorganic phosphorus compound to the organic phosphorus compound is 0.1-0.4:

1.

3. The composite corrosion and scale inhibitor according to claim 2, characterized in that, The inorganic phosphorus compound is one or more combinations of phosphoric acid and its potassium salt, sodium salt, ammonium salt, and aluminum salt.

4. The composite corrosion and scale inhibitor according to claim 2, wherein The organic phosphine compound contains at least one functional group of amino group, hydroxyl group, carboxyl group, or ester group.

5. The composite corrosion and scale inhibitor according to claim 1, wherein The polycarboxylic acid composition is a mixture of polyepoxysuccinic acid and sulfonate copolymer; the weight ratio of polyepoxysuccinic acid to the sulfonate copolymer is 0.75-2:

1.

6. The composite corrosion and scale inhibitor according to claim 5, characterized in that, The sulfonate copolymer is one or more combinations of acrylic acid / propylsulfonic acid copolymer, acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid copolymer, acrylic acid / 2-hydroxy-3-allyloxy-1-propenesulfonic acid copolymer, acrylic acid / methylethylacrylic acid sulfonate copolymer, acrylic acid / propoxypolyethoxysulfonate copolymer, maleic anhydride / propoxypolyethoxysulfonate copolymer, or acrylic acid / isoprene sulfonate / acrylic acid hydroxypropyl ester copolymer.

7. The composite corrosion and scale inhibitor according to claim 1, characterized in that, The organic amine compound is one or more combinations of ethanolamine, diethanolamine, triethanolamine, hexadecylamine, octadecylamine, bishexadecylamine, cyclohexylamine, aliphatic polyamine, aromatic polyamine, or ammonium dodecyl sulfate.

8. The composite corrosion and scale inhibitor according to claim 1, characterized in that, The amino acid is one or more combinations of glycine, tryptophan, alanine, or arginine; the water-soluble inorganic metal salt is zinc salt, sodium salt, potassium salt, or calcium salt.

9. A preparation method of a composite corrosion inhibitor and scale inhibitor, characterized in that, Including the following steps: Step 1: Dissolve the phosphorus compound in deionized water at 40-50 °C to obtain mixed solution 1; Step 2: Add the polycarboxylic acid composition to mixed solution 1 and stir and mix for 30-60 min to obtain mixed solution 2; Step 3: Sequentially add the organic amine compound, amino acid, and water-soluble inorganic metal salt to mixed solution 2 and adjust the solution pH to 8-10 to obtain mixed solution 3; Step 4: Filter mixed solution 3 to obtain a light yellow transparent liquid, namely the composite corrosion and scale inhibitor.

10. The composite corrosion and scale inhibitor according to any one of claims 1-8, characterized in that, This composite corrosion and scale inhibitor is applicable to industrial circulating cooling water systems.

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