A phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water and its preparation method

Abstract

The present invention discloses a phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water and a preparation method thereof. The phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water comprises the following raw materials in parts by weight: 10-25 parts of a modified heterocyclic corrosion inhibitor, 15-25 parts of acrylic acid-2-acrylamide-2-methacrylic acid copolymer, 10-20 parts of sodium humate, 10-15 parts of polyaspartic acid, 5-10 parts of polyepoxysuccinic acid, and 20-40 parts of deionized water. The present invention prepares a novel modified heterocyclic corrosion inhibitor by modifying 2-mercaptobenzothiazole. The modified heterocyclic corrosion inhibitor exhibits excellent scale and corrosion inhibition performance through a synergistic composite effect, and is characterized by high efficiency with a small amount of material.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water and a preparation method thereof. Background Art

[0002] The operation of circulating cooling water systems must address three major issues: scaling, corrosion, and microbial deposition. Currently, chemical treatment is an important means of addressing these three issues. During the operation of the cooling water, various agents such as corrosion inhibitors, scale inhibitors, and bactericides are continuously added to the system to prevent corrosion, scaling, and microbial growth, ensuring the efficient and stable operation of the cooling water system. Currently, most of the agents used are phosphorus-containing chemicals, and phosphorus can cause eutrophication of water bodies, causing serious damage to the ecological environment. In addition, most of the agents currently used use zinc salts to form a protective film to inhibit corrosion, and the enrichment of zinc in the soil will cause it to accumulate in plants, causing harm to people and animals who eat these plants. Therefore, the comprehensive phosphorus- and zinc-free treatment of cooling water is an inevitable trend, and the research on high-efficiency, phosphorus- and zinc-free corrosion inhibitors has become the current research focus of circulating cooling water treatment technology.

[0003] Currently, relevant phosphorus-free scale and corrosion inhibitor technologies have been applied in the field of circulating cooling water. For example, patent CN103523936A discloses a phosphorus-free scale and corrosion inhibitor for low-hardness water-based industrial circulating cooling water, CN103693765A discloses a phosphorus-free scale and corrosion inhibitor for central air-conditioning circulating cooling water and its preparation method, CN105314743A discloses a phosphorus-free scale and corrosion inhibitor suitable for negative hardness water quality and its preparation method, and CN114426336A discloses a phosphorus-free corrosion inhibitor for low temperature and a corrosion inhibition method for circulating cooling water. However, the phosphorus-free scale and corrosion inhibition technologies disclosed in the prior art still rely on zinc salts to form a protective film to achieve the corrosion inhibition effect, which is harmful to the environment. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water, comprising the following raw materials in parts by weight:

[0007] 10-25 parts of modified heterocyclic corrosion inhibitor, 15-25 parts of acrylic acid-2-acrylamide-2-methacrylic acid copolymer, 10-20 parts of sodium humate, 10-15 parts of polyaspartic acid, 5-10 parts of polyepoxysuccinic acid, and 20-40 parts of deionized water;

[0008] The modified heterocyclic corrosion inhibitor has a structural formula as shown in formula (I):

[0009]

[0010] The reaction equation for preparing the modified heterocyclic corrosion inhibitor is as follows:

[0011]

[0012] Furthermore, the modified heterocyclic corrosion inhibitor is prepared by the following method:

[0013] S1: Add 50 parts by weight of solvent and 20-25 parts by weight of 2-mercaptobenzothiazole to the reactor in sequence, stirring and dissolving;

[0014] S2: Add 0.5-1.0 parts by weight of the catalyst into the reactor and stir to dissolve;

[0015] S3: Under nitrogen protection, slowly add 25-30 parts by weight of octenylsuccinic anhydride dropwise, control the temperature at 50±2°C, and add for 2-3 hours. After the addition is complete, keep the temperature at 60-65°C for 1-2 hours, and then cool to room temperature to obtain the modified heterocyclic corrosion inhibitor.

[0016] Furthermore, the solvent is one of polyethylene glycol 200, acetone, and ethyl acetate; and the catalyst is one of tartaric acid, oxalic acid, salicylic acid, and aminosulfonic acid.

[0017] A method for preparing a phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water comprises the following steps:

[0018] S1: weigh the raw materials according to their composition;

[0019] S2: adding measured deionized water, modified heterocyclic corrosion inhibitor, acrylic acid-2-acrylamide-2-methacrylic acid copolymer, sodium humate, polyaspartic acid, and polyepoxysuccinic acid into the reactor in sequence and stirring;

[0020] S3: Stir at room temperature for 20-30 minutes to obtain phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water.

[0021] Due to the adoption of the above technical solution, the beneficial effects of the present invention include:

[0022] (1) The scale and corrosion inhibitor of the present invention does not contain phosphorus and zinc, causes little pollution to the environment after discharge, is easily biodegradable in water bodies, and meets the current national environmental protection requirements;

[0023] (2) The present invention uses sodium humate as the main component of the scale and corrosion inhibitor. Through the mutual fusion of the various components, the coordinated synergistic effect is enhanced, and it has excellent corrosion and scale inhibition performance;

[0024] (3) The present invention prepares a new type of modified heterocyclic corrosion inhibitor by modifying 2-mercaptobenzothiazole, which exhibits excellent scale and corrosion inhibition performance through complex synergistic effects and has the characteristics of low cost and high efficiency. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0026] Example 1

[0027] Preparation of modified heterocyclic corrosion inhibitor:

[0028] S1: Add 50 kg of polyethylene glycol 200 and 22 kg of 2-mercaptobenzothiazole to the reactor in sequence and stir to dissolve;

[0029] S2: Add 0.8 kg of tartaric acid into the reactor and stir to dissolve;

[0030] S3: Under nitrogen protection, slowly add 27 kg of octenylsuccinic anhydride dropwise, control the temperature at 50±2°C, and add for 2.5 hours. After the addition is complete, keep the temperature at 60-65°C for 1.5 hours, and then cool to room temperature to obtain the modified heterocyclic corrosion inhibitor.

[0031] Example 2

[0032] Preparation of modified heterocyclic corrosion inhibitor:

[0033] S1: Add 50 kg of ethyl acetate and 20 kg of 2-mercaptobenzothiazole to the reactor in sequence and stir to dissolve;

[0034] S2: Add 0.5 kg of salicylic acid into the reactor and stir to dissolve;

[0035] S3: Under nitrogen protection, slowly add 27 kg of octenylsuccinic anhydride dropwise, control the temperature at 50±2°C, and add for 2 hours. After the addition is complete, keep the temperature at 60-65°C for 2 hours, then cool to room temperature to obtain the modified heterocyclic corrosion inhibitor.

[0036] Example 3

[0037] Preparation of phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water:

[0038] S1: Weigh 20 kg of modified heterocyclic corrosion inhibitor (prepared in Example 1), 20 kg of acrylic acid-2-acrylamide-2-methacrylic acid copolymer, 15 kg of sodium humate, 12 kg of polyaspartic acid, 8 kg of polyepoxysuccinic acid, and 30 kg of deionized water;

[0039] S2: adding measured deionized water, modified heterocyclic corrosion inhibitor, acrylic acid-2-acrylamide-2-methacrylic acid copolymer, sodium humate, polyaspartic acid, and polyepoxysuccinic acid into the reactor in sequence and stirring;

[0040] S3: Stir at room temperature for 25 minutes to obtain phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water.

[0041] Example 4

[0042] Preparation of phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water:

[0043] S1: Weigh 10 kg of modified heterocyclic corrosion inhibitor (prepared in Example 1), 15 kg of acrylic acid-2-acrylamide-2-methacrylic acid copolymer, 10 kg of sodium humate, 10 kg of polyaspartic acid, 5 kg of polyepoxysuccinic acid, and 20 kg of deionized water;

[0044] S2: adding measured deionized water, modified heterocyclic corrosion inhibitor, acrylic acid-2-acrylamide-2-methacrylic acid copolymer, sodium humate, polyaspartic acid, and polyepoxysuccinic acid into the reactor in sequence and stirring;

[0045] S3: Stir at room temperature for 20 minutes to obtain phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water.

[0046] Example 5

[0047] Preparation of phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water:

[0048] S1: Weigh 25 kg of modified heterocyclic corrosion inhibitor (prepared in Example 1), 25 kg of acrylic acid-2-acrylamide-2-methacrylic acid copolymer, 20 kg of sodium humate, 15 kg of polyaspartic acid, 10 kg of polyepoxysuccinic acid, and 40 kg of deionized water;

[0049] S2: adding measured deionized water, modified heterocyclic corrosion inhibitor, acrylic acid-2-acrylamide-2-methacrylic acid copolymer, sodium humate, polyaspartic acid, and polyepoxysuccinic acid into the reactor in sequence and stirring;

[0050] S3: Stir at room temperature for 30 minutes to obtain phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water.

[0051] Comparative Example 1

[0052] The preparation method of the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water is basically the same as that in Example 3, except that in step S1, 25 kg of the modified heterocyclic corrosion inhibitor is replaced by 25 kg of 2-mercaptobenzothiazole.

[0053] Comparative Example 2

[0054] The preparation method of the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water is basically the same as that in Example 3, except that in step S1, 25 kg of the modified heterocyclic corrosion inhibitor is replaced by 25 kg of benzotriazole.

[0055] Comparative Example 3

[0056] The preparation method of the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water is basically the same as that in Example 3, except that in step S1, 25 kg of the modified heterocyclic corrosion inhibitor is replaced by 25 kg of 5-butyl-1H-benzotriazole (5-butyl-benzotriazole).

[0057] Comparative Example 4

[0058] The preparation method of the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water is basically the same as that in Example 3, except that in step S1, 25 kg of the modified heterocyclic corrosion inhibitor is replaced by 25 kg of octenyl succinic anhydride.

[0059] Comparative Example 5

[0060] The preparation method of the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water is basically the same as that in Example 3, except that in step S1, 25 kg of modified heterocyclic corrosion inhibitor is replaced by 13.8 kg of octenylsuccinic anhydride and 11.2 kg of 2-mercaptobenzothiazole.

[0061] Comparative Example 6

[0062] The preparation method of the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water is basically the same as that in Example 3, except that, in step S2, no modified heterocyclic corrosion inhibitor is added.

[0063] The scale and corrosion inhibitors prepared in the examples of the present invention and those prepared in the comparative examples were tested for scale and corrosion inhibition performance. The main water quality indicators of the test water samples are shown in Table 1. The test was conducted at a dosing concentration of 15 mg / L, a test magnification of 8.0, and a standard corrosion coupon made of 20# carbon steel. The test procedure was conducted in accordance with GB / T 18832-2008 and GB / T 18175-2014. The test results are shown in Table 2.

[0064] Table 1

[0065]

[0066] Table 2

[0067] Project Potion Corrosion inhibition rate / % Scale inhibition rate / % Example 3 99.18 99.32 Example 4 99.03 99.21 Example 5 99.20 99.29 Comparative Example 1 89.16 98.97 Comparative Example 2 87.29 98.86 Comparative Example 3 89.19 99.07 Comparative Example 4 82.89 96.35 Comparative Example 5 87.33 97.93 Comparative Example 6 80.75 90.68

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water, characterized in that: The composition comprises the following raw materials in parts by weight: 10-25 parts of modified heterocyclic corrosion inhibitor, 15-25 parts of acrylic acid-2-acrylamide-2-methacrylic acid copolymer, 10-20 parts of sodium humate, 10-15 parts of polyaspartic acid, 5-10 parts of polyepoxysuccinic acid, and 20-40 parts of deionized water; The modified heterocyclic corrosion inhibitor has a structural formula as shown in formula (I): （I）； The modified heterocyclic corrosion inhibitor is prepared by the following method: S1: Add 50 parts by weight of solvent and 20-25 parts by weight of 2-mercaptobenzothiazole to the reactor in sequence, stirring and dissolving; S2: Add 0.5-1.0 parts by weight of the catalyst into the reactor and stir to dissolve; S3: Under nitrogen protection, slowly add 25-30 parts by weight of octenylsuccinic anhydride dropwise, control the temperature at 50±2°C, and add for 2-3 hours. After the addition is complete, keep the temperature at 60-65°C for 1-2 hours, and then cool to room temperature to obtain a modified heterocyclic corrosion inhibitor; The solvent is one of polyethylene glycol 200, acetone, and ethyl acetate; and the catalyst is one of tartaric acid, oxalic acid, salicylic acid, and aminosulfonic acid.

2. A method for preparing the phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water according to claim 1, characterized in that: The following steps are involved: S1: weigh the raw materials according to their composition; S2: adding measured deionized water, modified heterocyclic corrosion inhibitor, acrylic acid-2-acrylamide-2-methacrylic acid copolymer, sodium humate, polyaspartic acid, and polyepoxysuccinic acid into the reactor in sequence and stirring; S3: Stir at room temperature for 20-30 minutes to obtain phosphorus-free and zinc-free scale and corrosion inhibitor for circulating cooling water.

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