A method for preparing a closed system circulating water corrosion inhibitor

Abstract

The invention discloses a method for preparing a closed system circulating water corrosion inhibitor, comprising the following steps: S1: mixing an organic corrosion inhibitor with water to form a suspension; S2: adding an alkaline solvent to the suspension and mixing and stirring until the solution is transparent; S3: sequentially adding polyether, non-ferrous metal corrosion inhibitor, and tracer to the solution and mixing and stirring to prepare the corrosion inhibitor. The invention has the advantages of low dosage of the agent, wide range of water quality, low cost, etc., and has a good corrosion inhibition effect on both ferrous metals and non-ferrous metals, and can be effectively applied to large-scale closed circulating water systems.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a method for preparing a closed system circulating water corrosion inhibitor. Background Art

[0002] With the acceleration of industrialization, the proportion of industrial water in total water consumption continues to rise, among which the circulating water system accounts for more than 60% of the total industrial water consumption. In view of the huge water consumption of the circulating water system, in order to effectively reduce its consumption, more and more industrial enterprises have begun to adopt large-scale closed-loop cooling water systems to replace traditional open-loop circulating water systems. Closed-loop cooling water systems usually use softened water. Compared with ordinary industrial circulating water, softened water is not easy to produce scale and has obvious advantages. However, softened water is highly corrosive to ferrous and non-ferrous metals. Therefore, in closed systems using softened water, effective anti-corrosion measures must be implemented to slow down the corrosion effects on equipment and pipelines.

[0003] Nitrite and its composite corrosion inhibitor, which are commonly used in the current market, are widely used because of their excellent slow-release effect to deal with corrosion problems in softened water closed systems. However, nitrite is not only toxic, but also has a large dosage. After a large amount of use, it will cause a significant increase in water conductivity. These shortcomings have gradually made it lose market favor. In order to effectively solve the corrosion problem of closed circulating water systems, new softened water closed system corrosion inhibitors continue to emerge. For example, patent CN202111331864 discloses a new type of softened water closed system corrosion inhibitor. Although the amount of the corrosion inhibitor is low, its ingredients contain expensive ammonium molybdate and sodium tungstate, resulting in low cost performance. In addition, the formula also contains a high proportion of organic phosphoric acid hydroxyethyl diphosphonic acid, which not only makes the phosphorus content high and does not meet the current environmental protection requirements, but also fails to control the corrosion rate within an extremely low range. Furthermore, the corrosion inhibitor is only applicable to water with a conductivity of 1-10μs / cm, which greatly limits its scope of application. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides a method for preparing a closed system circulating water corrosion inhibitor, which has the advantages of low dosage of the agent, wide adaptability to water quality range, low cost, etc., and has a good corrosion inhibition effect on both ferrous metals and non-ferrous metals, and can be effectively applied to large-scale closed circulating water systems.

[0005] The main technical solutions adopted in the present invention are:

[0006] A method for preparing a closed system circulating water corrosion inhibitor comprises the following steps:

[0007] S1: Mixing the organic corrosion inhibitor with water to form a suspension;

[0008] S2: adding an alkaline solvent to the suspension and mixing and stirring until the solution is transparent;

[0009] S3: Add polyether, nonferrous metal corrosion inhibitor and tracer into the solution in sequence, mix and stir to prepare corrosion inhibitor.

[0010] Preferably, the addition amount of the organic corrosion inhibitor is 1-10% by mass.

[0011] Preferably, the organic corrosion inhibitor is one or both of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and diethanolamine borate.

[0012] Preferably, the amount of the alkaline solvent added is 5-10% by mass.

[0013] Preferably, the alkaline solvent is one or more of monoethanolamine, triethanolamine and diglycolamine.

[0014] Preferably, the amount of the polyether added is 1-10% by mass.

[0015] Preferably, the polyether is one or both of fatty amine polyoxyethylene ether AC-1810 and fatty amine polyoxyethylene ether AC-1812, calculated by mass fraction.

[0016] Preferably, the amount of the non-ferrous metal corrosion inhibitor added is 1-3% by mass.

[0017] Preferably, the non-ferrous metal corrosion inhibitor is one or more of fatty acid polyvinyl ether phosphate, benzotriazole BTA, tolutriazole TTA, and tolutriazole sodium chloride HRA.

[0018] Preferably, the added amount of the tracer is 0.05% by mass, and the tracer is 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt.

[0019] Beneficial effects: The present invention provides a method for preparing a closed system circulating water corrosion inhibitor, which has the following advantages:

[0020] (1) The corrosion inhibitor of the present invention has a hydrophilic group that can be adsorbed on the metal surface and a hydrophobic group that shields the metal surface. It can form an effective adsorption film at a low dose. Even if the dosage of the agent is as low as 50 ppm, it can still play an excellent corrosion inhibition role. It is also applicable to a wide range of water quality and can have a good corrosion inhibition effect on soft water with a conductivity of less than 200 μs / cm.

[0021] (3) The corrosion inhibition effect of the corrosion inhibitor of the present invention on ferrous metal materials such as carbon steel, cast iron, stainless steel and non-ferrous metal materials such as copper and aluminum is significantly better than that of the existing commonly used closed water corrosion inhibitors, and the corrosion rate can be controlled to less than 0.005 mm / a. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0023] Example 1

[0024] In this embodiment 1, a closed system circulating water corrosion inhibitor is prepared, and the specific method is as follows:

[0025] First, use about 84.5g of deionized water to mix 5g of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and stir until it becomes a suspension, add 2.5g of monoethanolamine and 2.5g of triethanolamine, stir until the solution is transparent, and then add 2.5g of fatty amine polyoxyethylene ether AC-1810, 2.0g of benzotriazole BTA, 1.0g of fatty acid polyethylene ether phosphate and 0.05g of tracer (1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt) in sequence, and stir until completely dissolved.

[0026] Example 2

[0027] In this Example 2, a closed system circulating water corrosion inhibitor was prepared, and the specific method was as follows:

[0028] First, use about 72g of deionized water to mix 5g of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and 5g of diethanolamine borate and stir until a suspension is obtained. Then add 5g of triethanolamine and 5g of diglycolamine and stir until the solution is transparent. Subsequently, 5g of fatty amine polyoxyethylene ether AC-1810, 2.0g of methylbenzotriazole TTA, 1.0g of fatty acid polyethylene ether phosphate and 0.05g of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt are added in sequence and stirred until completely dissolved.

[0029] Example 3

[0030] In this Example 3, a closed system circulating water corrosion inhibitor was prepared, and the specific method was as follows:

[0031] First, use about 72g of deionized water to mix 10g of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and stir until it becomes a suspension, then add 10g of triethanolamine and stir until the solution is transparent, then add 5g of fatty amine polyoxyethylene ether AC-1812, 2.0g of chloromethylbenzotriazole sodium salt HRA, 1.0g of fatty acid polyethylene ether phosphate, and 0.05g of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt and stir until completely dissolved.

[0032] Example 4

[0033] In this embodiment 4, a closed system circulating water corrosion inhibitor was prepared, and the specific method was as follows:

[0034] First, use about 72g of deionized water to mix 7.5g of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and 2.5g of diethanolamine borate and stir until a suspension is formed. Then add 7.5g of triethanolamine and 2.5g of diglycolamine and stir until the solution is transparent. Subsequently, add 5g of fatty amine polyoxyethylene ether AC-1812, 3g of benzotriazole BTA, and 0.05g of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt in sequence and stir until completely dissolved.

[0035] Example 5

[0036] In this Example 5, a closed system circulating water corrosion inhibitor was prepared, and the specific method was as follows:

[0037] First, use about 72g of deionized water to mix 2.5g of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and 7.5g of diethanolamine borate and stir until a suspension is obtained. Then add 2.5g of triethanolamine and 7.5g of diglycolamine and stir until the solution is transparent. Subsequently, add 5g of fatty amine polyoxyethylene ether AC-1810, 3g of methylbenzotriazole sodium salt HRA, and 0.05g of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt in sequence and stir until completely dissolved.

[0038] The total mass of the closed system circulating water corrosion inhibitor in Examples 1-5 is 100.05 g, approximately 100 g.

[0039] (1) Comparative test of water treatment corrosion inhibition performance 1

[0040] Reverse osmosis water was used as test water, and its water quality data was: pH value 6.62, conductivity 2μs / cm. The rotating plate test was carried out in accordance with "Determination of corrosion inhibition performance of water treatment - rotating plate method" (GB / T18175-2014). The commercially available soft water sealed corrosion inhibitor Nalco TRAC107PLUS was used as a comparative example, and a comparative test was carried out between it and the sealed corrosion inhibitor prepared in Examples 1-5. The closed operation was carried out for 30 days, and the corrosion inhibition test results are shown in Table 1.

[0041] Table 1 Corrosion inhibition test results of comparative test 1

[0042]

[0043] As can be seen from Table 1, when the addition concentration is the same, the corrosion rate of Examples 1-5 is significantly lower than that of the comparative example. Even if the addition concentration of the comparative example is increased by 20 times, the corrosion effect of Examples 1-5 is still better than that of the comparative example. In addition, the corrosion rate of Examples 1-5 is much lower than the corrosion rate specified by the national standard, and the corrosion inhibition effect is excellent. Among them, the national standard GB50050-2017 stipulates that the corrosion rate of carbon steel is ≤0.075mm / a, and the corrosion rate of stainless steel and brass is ≤0.005mm / a.

[0044] (2) Comparative test of water treatment corrosion inhibition performance 2

[0045] The surface water from a certain place was used as the test water. The water quality data were as follows: conductivity 166μs / cm, turbidity 1.2mg / L, calcium hardness 33mg / L, magnesium hardness 5.8mg / L, total alkalinity 29mg / L, Cl - 53mg / L. A rotating coupon test was conducted with reference to "Determination of Corrosion Inhibition Performance of Water Treatment - Rotating Coupon Method" (GB / T18175-2014), and the commercially available soft water sealed corrosion inhibitor NalcoTRAC107PLUS was used as a comparative example, and a comparative test was conducted between it and the sealed corrosion inhibitor prepared in Examples 1-5. The sealed operation lasted for 30 days, and the corrosion inhibition test results are shown in Table 2.

[0046] Table 2 Corrosion inhibition test results of comparative test 2

[0047]

[0048] As can be seen from Table 2, when the addition concentration is the same, the corrosion rate of Examples 1-5 is significantly lower than that of the comparative example. Even if the addition concentration of the comparative example is increased by 20 times, the corrosion effect of Examples 1-5 is still better than that of the comparative example. In addition, the corrosion rate of Examples 1-5 is much lower than the corrosion rate specified by the national standard, and the corrosion inhibition effect is excellent. Among them, the national standard GB50050-2017 stipulates that the corrosion rate of carbon steel is ≤0.075mm / a, and the corrosion rate of stainless steel and brass is ≤0.005mm / a.

[0049] The above description is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention.

Claims

1. A method for preparing a closed system circulating water corrosion inhibitor, characterized in that: The following steps are involved: S1: Mixing the organic corrosion inhibitor with water to form a suspension; S2: adding an alkaline solvent to the suspension and mixing and stirring until the solution is transparent; S3: Add polyether, nonferrous metal corrosion inhibitor and tracer into the solution in sequence, mix and stir to prepare corrosion inhibitor.

2. The method for preparing a closed system circulating water corrosion inhibitor according to claim 1, characterized in that: The amount of the organic corrosion inhibitor added is 1-10% by mass.

3. The method for preparing a closed system circulating water corrosion inhibitor according to claim 2, characterized in that: The organic corrosion inhibitor is one or two of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and diethanolamine borate.

4. The method for preparing a closed system circulating water corrosion inhibitor according to claim 1, characterized in that: The amount of the alkaline solvent added is 5-10% by mass.

5. The method for preparing a closed system circulating water corrosion inhibitor according to claim 4, characterized in that: The alkaline solvent is one or more of monoethanolamine, triethanolamine and diglycolamine.

6. The method for preparing a closed system circulating water corrosion inhibitor according to claim 1, characterized in that: The amount of the polyether added is 1-10% by mass.

7. The method for preparing a closed system circulating water corrosion inhibitor according to claim 6, characterized in that: Calculated by mass fraction, the polyether is one or both of fatty amine polyoxyethylene ether AC-1810 and fatty amine polyoxyethylene ether AC-1812.

8. The method for preparing a closed system circulating water corrosion inhibitor according to claim 1, characterized in that: Calculated by mass fraction, the addition amount of non-ferrous metal corrosion inhibitor is 1-3%.

9. The method for preparing a closed system circulating water corrosion inhibitor according to claim 8, characterized in that: The non-ferrous metal corrosion inhibitor is one or more of fatty acid polyvinyl ether phosphate, benzotriazole BTA, tolutriazole TTA, and tolutriazole sodium chloride HRA.

10. The method for preparing a closed system circulating water corrosion inhibitor according to claim 1, characterized in that: Calculated by mass fraction, the added amount of the tracer is 0.05%, and the tracer is 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt.

Images