Circulating water scale and corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of scale and corrosion inhibitors, and particularly relates to a circulating water scale and corrosion inhibitor and a preparation method and application thereof. The invention provides a circulating water scale and corrosion inhibitor. The circulating water scale and corrosion inhibitor comprises the following components in percentage by mass: 10-18% of amino trimethylene phosphonic acid, 40-50% of polyacrylic acid, 0.5-1.2% of benzotriazole and the balance of water. The circulating water scale and corrosion inhibitor provided by the invention has no corrosion effect on various metal substances, has relatively strong complexing ability on metal ions in wastewater, and does not corrode equipment during scale inhibition, so that the application range is expanded, and the circulating water scale and corrosion inhibitor provided by the invention is used for an open-type circulating water system. The circulating water scale and corrosion inhibitor provided by the invention has relatively high scale inhibition and slow release efficiency under the combined action of all the components.

Description

Technical Field

[0001] The present invention belongs to the technical field of scale and corrosion inhibitors, and particularly relates to a scale and corrosion inhibitor for circulating water, a preparation method thereof, and an application thereof. Background Art

[0002] Circulating water plays a crucial role in industrial production systems. However, the circulating water used has high strength and alkalinity and has serious scaling characteristics. In various situations where the water temperature is higher than the ambient temperature, the scaling of inorganic salts such as calcium carbonate will bring serious consequences. When used as a circulating medium in an industrial circulating water system, it will cause water quality deterioration, problems such as corrosion and scaling, resulting in blockage or leakage of heat exchangers and their pipelines, seriously affecting the normal operation of production devices. At present, the phenomenon of scaling is mainly alleviated by adding scale and corrosion inhibitors to the circulating water. However, the scale and corrosion inhibition efficiency of existing circulating water scale and corrosion inhibitors is relatively low. Summary of the Invention

[0003] In view of this, the present invention provides a scale and corrosion inhibitor for circulating water, a preparation method thereof, and an application thereof. The scale and corrosion inhibitor for circulating water provided by the present invention has weak corrosion to metals and can be applied to a variety of metal devices without corroding the metal devices. At the same time, the scale and corrosion inhibitor for circulating water provided by the present invention has a high scale and corrosion inhibition efficiency.

[0004] In order to solve the above technical problems, the present invention provides a scale and corrosion inhibitor for circulating water, comprising the following components in mass percentage:

[0005]

[0006] Preferably, it comprises the following components in mass percentage:

[0007]

[0008] The present invention also provides a preparation method of the scale and corrosion inhibitor for circulating water according to the above technical solution, comprising the following steps:

[0009] Mix aminotrimethylenephosphonic acid, polyacrylic acid, benzotriazole and water to obtain the scale and corrosion inhibitor for circulating water.

[0010] Preferably, the mixing is carried out under stirring, and the stirring time is 4 - 6 h.

[0011] The present invention also provides an application of the scale and corrosion inhibitor for circulating water according to the above technical solution or the scale and corrosion inhibitor for circulating water prepared by the preparation method according to the above technical solution in an open cooling water system.

[0012] The present invention provides a scale and corrosion inhibitor for circulating water, which comprises the following components in mass percentage: 10-18% of aminotrimethylenephosphonic acid, 40-50% of polyacrylic acid, 0.5-1.2% of benzotriazole and the balance of water. The scale and corrosion inhibitor for circulating water provided by the present invention has no corrosive effect on various metal substances (carbon steel, copper, stainless steel), has a strong complexing ability for metal ions in circulating water, and will not corrode equipment while inhibiting scale, thus expanding the application range. The scale and corrosion inhibitor for circulating water provided by the present invention can be used in an open cooling water system. The scale and corrosion inhibitor for circulating water provided by the present invention has a high scale inhibition efficiency under the combined action of each component. Detailed implementation mode

[0013] The present invention provides a scale and corrosion inhibitor for circulating water, which comprises the following components in mass percentage:

[0014]

[0015] In the present invention, if not otherwise specified, all raw materials are conventional commercially available products.

[0016] In the present invention, based on mass percentage, the scale and corrosion inhibitor for circulating water comprises 10-18% of aminotrimethylenephosphonic acid, preferably 12-15%. In the present invention, the aminotrimethylenephosphonic acid (ATMP) has excellent scale inhibition performance at 200 °C, good stability, and excellent effect on inhibiting the formation of calcium carbonate scale. And it can form stable complexes with various metal ions such as iron, copper, aluminum, and zinc, and has good dispersion performance. When the dosage of aminotrimethylenephosphonic acid in the scale and corrosion inhibitor for circulating water exceeds 30 ppm, the scale and corrosion inhibitor for circulating water has good corrosion inhibition performance.

[0017] In the present invention, based on mass percentage, the scale and corrosion inhibitor for circulating water comprises 40-50% of polyacrylic acid, preferably 45-50%. In the present invention, the molecular weight of the polyacrylic acid (PAA) is preferably 2000-5000, more preferably 3000-4000. In the present invention, the polyacrylic acid can form stable compounds with metal ions such as calcium ions and magnesium ions, and has excellent decomposition effect on calcium carbonate and calcium hydroxide in water, avoiding the formation of calcium scale.

[0018] In the present invention, based on mass percentage, the scale and corrosion inhibitor for circulating water comprises 0.5-1.2% of benzotriazole, preferably 0.8-1.0%. In the present invention, the benzotriazole (BTA) has an anticorrosion effect on metal materials such as copper, aluminum, cast iron, nickel, and zinc, thus reducing the corrosiveness of the scale and corrosion inhibitor for circulating water to equipment.

[0019] In the present invention, based on mass percentage, the scale and corrosion inhibitor for circulating water comprises the balance of water. In the present invention, the water is preferably demineralized water.

[0020] The present invention also provides a preparation method of the circulating water scale and corrosion inhibitor described in the above technical solution, comprising the following steps:

[0021] Mix aminotrimethylene phosphonic acid, polyacrylic acid, benzotriazole and water to obtain the circulating water scale and corrosion inhibitor.

[0022] In the present invention, the mixing preferably comprises the following steps:

[0023] First mix aminotrimethylene phosphonic acid and water to obtain a first solution;

[0024] Second mix polyacrylic acid and the first solution to obtain a second solution;

[0025] Third mix benzotriazole and a third solution to obtain the circulating water scale and corrosion inhibitor.

[0026] In the present invention, the first mixing is preferably carried out under stirring, the rotation speed of the stirring is preferably 60 - 80 r / min, more preferably 65 - 70 r / min; the stirring time is preferably 1 - 2 h, more preferably 2 h.

[0027] In the present invention, the second mixing is preferably carried out under stirring, the rotation speed of the stirring is preferably 70 - 90 r / min, more preferably 75 - 80 r / min; the stirring time is preferably 1 - 2 h, more preferably 1 h.

[0028] In the present invention, the third mixing is preferably carried out under stirring, the rotation speed of the stirring is preferably 80 - 100 r / min, more preferably 85 - 90 r / min; the stirring time is preferably 2 - 3 h, more preferably 3 h.

[0029] In the present invention, the sum of the stirring times of the first mixing, the second mixing and the third mixing is preferably 4 - 7 h, more preferably 5 - 6 h.

[0030] The present invention also provides the application of the circulating water scale and corrosion inhibitor described in the above technical solution or the circulating water scale and corrosion inhibitor prepared by the preparation method described in the above technical solution in an open cooling water system. In the present invention, the circulating water scale and corrosion inhibitor has no corrosive effect on various equipment composed of metal substances in the open cooling water system and has a strong complexing ability for metal ions in water.

[0031] The circulating water scale and corrosion inhibitor provided by the present invention is applicable to scale and corrosion inhibition of circulating water with high hardness and high chloride ion content, and the dosing amount of the circulating water scale and corrosion inhibitor is preferably 25 - 50 ppm.

[0032] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0033] Example 1

[0034] Amino trimethylene phosphonic acid and demineralized water were stirred for 2 h at a rotation speed of 70 r / min to obtain a first solution;

[0035] Polyacrylic acid and the first solution were stirred for 2 h at a rotation speed of 80 r / min to obtain a second solution;

[0036] Benzotriazole and the second solution were stirred for 3 h at a rotation speed of 90 r / min to obtain a circulating water scale and corrosion inhibitor, wherein the mass percentage content of amino trimethylene phosphonic acid was 15%, the mass percentage content of polyacrylic acid was 50%, and the mass percentage content of benzotriazole was 0.5%.

[0037] Example 2

[0038] The scale and corrosion inhibitor was prepared according to the method of Example 1, except that the mass percentage content of amino trimethylene phosphonic acid was 18%, the mass percentage content of polyacrylic acid was 45%, and the mass percentage content of benzotriazole was 0.5%.

[0039] Example 3

[0040] The scale and corrosion inhibitor was prepared according to the method of Example 1, except that the mass percentage content of amino trimethylene phosphonic acid was 12%, the mass percentage content of polyacrylic acid was 45%, and the mass percentage content of benzotriazole was 0.5%.

[0041] The scale and corrosion inhibitor prepared in Example 1 was used in an open cooling water system with a pH value of 9.0, a calcium hardness (calculated as calcium carbonate) of 1100 mg / L, a total alkalinity of 300 mg / L, and a chloride ion content of 1000 mg / L. Referring to "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Specimen Method" (GB / T 18175-2014), the corrosion inhibition performance of the circulating water scale and corrosion inhibitor prepared in this Example 1 was determined: The test hanging specimens were A3 carbon steel, brass, and 304 stainless steel type I standard corrosion hanging specimens. Two specimens of each material were taken, and the results were averaged for experiments at room temperature. The results were as follows: The corrosion rate of carbon steel was 0.035 mm / a, and the corrosion rates of 304 stainless steel and brass were not detected.

[0042] Under the water quality indicators: pH value of 9.0, calcium hardness (calculated as calcium carbonate) of 1100 mg / L, and total alkalinity of 300 mg / L, the scale inhibition performance of the scale and corrosion inhibitor prepared in Example 1 was detected by the static calcium carbonate scale inhibition method and the static calcium phosphate scale inhibition method. The results are as follows: the calcium carbonate scale inhibition rate is 97%, and the calcium phosphate scale inhibition rate is 96.6%.

[0043] The scale and corrosion inhibitor prepared in Example 2 was used in the PVC circulating water system of Inner Mongolia Yidong Group Dongxing Chemical Co., Ltd. The concentration multiple was 4 times, and the use concentration was 40 ppm based on the makeup water volume. The corrosion rates of carbon steel, stainless steel, and copper were all lower than the national standards (carbon steel ≤ 0.075 mm / a, stainless steel ≤ 0.005 mm / a, copper ≤ 0.005 mm / a), meeting the standard requirements of the "Design Code for Industrial Recirculating Cooling Water Treatment" (GB 50050-2017).

[0044] The scale and corrosion inhibitor for circulating water prepared in Example 3 was used in circulating water with a chloride ion content of 500 mg / L. Referring to the "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Specimen Method" (GB / T 18175-2014), the corrosion inhibition performance of the scale and corrosion inhibitor for circulating water prepared in this Example 3 was determined: The test hanging specimens used A3 carbon steel and 304 stainless steel type I standard corrosion hanging specimens, and 3 specimens were taken for each material, and the results were averaged. The results are as follows: the corrosion rate of carbon steel is 0.047 mm / a, and the corrosion rate of 304 stainless steel is 0.002 mm / a.

[0045] From the above test results, it can be seen that the calcium carbonate and calcium phosphate scale inhibition rates of the scale and corrosion inhibitor for circulating water provided by the present invention are both above 96%, the carbon steel corrosion rate is below 0.05 mm / a, and the copper and stainless steel corrosion rates are below 0.002 mm / a.

[0046] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all of them. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all belong to the protection scope of the present invention.

Claims

1. A circulating water scale and corrosion inhibitor, characterized in that, Comprising components with the following mass percentages:

2. The scale and corrosion inhibitor for circulating water according to claim 1, characterized in that, Comprising components with the following mass percentages:

3. The preparation method of the circulating water scale and corrosion inhibitor according to claim 1 or 2, comprising the following steps: Mix aminotrimethylene phosphonic acid, polyacrylic acid, benzotriazole and water to obtain the circulating water scale and corrosion inhibitor.

4. The preparation method according to claim 3, characterized in that, The mixing is carried out under stirring, and the stirring time is 4 to 6 h.

5. The application of the circulating water scale and corrosion inhibitor according to claim 1 or 2 or the circulating water scale and corrosion inhibitor prepared by the preparation method according to any one of claims 3 to 4 in an open cooling water system.

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