Phosphorus-free pre-filming agent for circulating cooling water and preparation method thereof

Abstract

The invention provides an efficient and environment-friendly circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, and belongs to the technical field of water treatment.The pre-filming agent is prepared from sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, a terpolymer, sulfuric acid and benzotriazole; the terpolymer is prepared from 2-phenoxy ethyl acrylate, metacrylic acid ester and acrylic ester through a thermal polymerization reaction; by adding the benzotriazole, the corrosion resistance is remarkably improved, the pre-filming efficiency is further enhanced, a layer of stable protective film can be rapidly formed on the metal surface of equipment, the service life of the equipment is effectively prolonged, and the overall production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, in particular to a phosphorus-free pre-filming agent for circulating cooling water and a preparation method thereof. Background Art

[0002] Because the industrial circulating cooling water system needs to be cleaned and pre-filmed before the new system is put into operation, the old system must be pre-filmed in time after cleaning to protect the circulating water system. Pre-filming agent is a type of chemical that can pre-form a protective film on the metal surface during the pre-treatment process of water treatment. The use of pre-filming agent can effectively remove residual rust and scale, form a composite metal film with a special potential on the metal surface, balance the potential of the system material, effectively prevent electrochemical corrosion and under-scale corrosion, and extend the service life of the equipment.

[0003] At present, most industrial circulating water treatment pre-filming agents use phosphate as a pre-filming agent. However, the phosphorus content is high, causing water pollution and eutrophication problems, which cannot meet the direct environmental discharge standards. In recent years, the problem of water eutrophication has become more and more serious. Phosphorus is a nutrient source for microorganisms, and its impact on the environment is becoming increasingly severe. In view of the above problems, phosphorus-free water treatment agents are becoming a future development trend. Phosphorus-free pre-filming agents do not contain heavy metals and phosphates, which reduces environmental pollution from the source, greatly reduces the difficulty and cost of wastewater treatment, and reduces the burden of enterprises in environmental protection treatment. It minimizes the emission of heavy metals and has minimal harm to the ecological environment such as soil and water sources, which is conducive to protecting the ecological environment and human health. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems in the prior art and to provide a phosphorus-free pre-filming agent for circulating cooling water and a preparation method thereof.

[0005] The object of the present invention can be achieved by the following technical scheme: a circulating cooling water non-phosphorus pre-filming agent, the reagents for configuring the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), inorganic salt (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), benzotriazole (AR), wherein the specific amount of each reagent is as follows:

[0006] The sodium gluconate accounts for 10% to 30% and is used to improve the wettability and spreadability of the solution and promote the film-forming process;

[0007] The zinc sulfate heptahydrate accounts for 5% to 15% and is used to provide zinc ions to participate in the film-forming process. The zinc ions can form a protective film on the metal surface to improve the corrosion resistance of the metal.

[0008] The inorganic salt accounts for 1% to 5% and is used to adjust the ionic strength of the solution or as an auxiliary component. In addition, the addition of sodium chloride can affect the conductivity and film-forming effect of the solution.

[0009] The copper sulfate pentahydrate accounts for 1% to 5% and is used to provide copper ions, which may help enhance the corrosion resistance of the protective film;

[0010] The terpolymer accounts for 2% to 10% and is used to improve the stability and performance of the solution;

[0011] The sulfuric acid accounts for 1% to 3% and is used to adjust the pH value of the solution. The addition of sulfuric acid can affect the film-forming process and the performance of the protective film.

[0012] The benzotriazole accounts for 0.5% to 5% and can be used as a corrosion inhibitor to form a protective film on the metal surface, further improving the anti-corrosion effect of the pre-filming agent.

[0013] Preferably, the terpolymer is obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator.

[0014] Preferably, the solvent of the pre-filming agent is pure water.

[0015] Preferably, the inorganic salt is one of sodium chloride, potassium chloride or sodium sulfate.

[0016] Preferably, the pre-filming effect of the pre-filming agent is tested by: using a carbon steel coupon and testing with a coupon corrosion tester;

[0017] The inspection process is carried out within a temperature range of 20 to 40°C.

[0018] The test duration is 24 to 48 hours.

[0019] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, characterized in that the specific steps are as follows:

[0020] S1 Weighing reagents: Determine the optimal dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, inorganic salt, copper sulfate pentahydrate, terpolymer, and benzotriazole in sequence, add them into a beaker, add water and stir to dissolve;

[0021] S2 prepares sulfuric acid solution: absorb a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature;

[0022] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0023] Preferably, in step S1, a magnetic stirrer is used as an auxiliary tool to perform stirring operation at room temperature, and sufficient stirring for a certain period of time is performed to ensure that a variety of solid medicines can be evenly dissolved to form a uniform solution.

[0024] Preferably, in step S2, after the concentrated sulfuric acid is prepared into a solution, it is necessary to wait for the sulfuric acid solution to cool naturally to room temperature before performing subsequent transfer operations to ensure the safety of the operation.

[0025] Preferably, in step S3, in order to detect the optimal concentration of the pre-filming agent, it is necessary to configure it into solutions of different concentrations, including 300 mg / L, 500 mg / L, and 700 mg / L, and then put these solutions of different concentrations into the pre-filming effect inspection test, and determine the optimal concentration of the pre-filming agent by observing and analyzing the test results.

[0026] Compared with the prior art, the circulating cooling water non-phosphorus pre-filming agent and its preparation method have the following beneficial effects:

[0027] 1. The present invention provides a circulating cooling water non-phosphorus pre-filming agent, which incorporates a benzotriazole component, significantly prolongs the color change time of the copper sulfate solution, enhances the corrosion resistance of the pre-filming agent, and thus optimizes the pre-filming effect;

[0028] 2. The present invention provides a circulating cooling water phosphorus-free pre-filming agent. When the concentration of the pre-filming agent reaches 500 mg / L, it shows a relatively obvious pre-filming effect, which not only ensures excellent protective performance, but also effectively avoids unnecessary consumption of materials, and realizes the combination of high efficiency and economy.

[0029] 3. The phosphorus-free pre-filming agent for circulating cooling water provided by the present invention exhibits wide temperature adaptability in application, does not require specific ambient temperature conditions, and can function stably in a wide temperature range of 20 to 40°C, thereby ensuring excellent pre-filming effect.

[0030] 4. The phosphorus-free pre-filming agent for circulating cooling water provided by the present invention has rapid film-forming ability, does not contain phosphorus and has environmentally friendly characteristics, will not have a negative impact on the environment, and is helpful in maintaining ecological balance, reflecting the concept of green chemistry.

[0031] 5. The preparation method of the circulating cooling water phosphorus-free pre-filming agent provided by the present invention is simple and efficient, the required raw materials are low-cost and easy to obtain, and the operation process is simple, which provides a solid feasibility foundation for large-scale production and application.

[0032] In summary, the present invention provides an efficient and environmentally friendly circulating cooling water phosphorus-free pre-filming agent and a preparation method thereof. By adding benzotriazole, the corrosion resistance is significantly improved, the pre-filming efficiency is further enhanced, and a stable protective film can be quickly formed on the metal surface of the equipment, thereby effectively extending the service life of the equipment and improving the overall production efficiency. DETAILED DESCRIPTION

[0033] The following are specific embodiments of the present invention and combined with tables to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments. Specific embodiment one:

[0035] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), inorganic salt (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0036] The sodium gluconate accounts for 20% and is used to improve the wettability and spreadability of the solution and promote the film-forming process;

[0037] The zinc sulfate heptahydrate accounts for 10% and is used to provide zinc ions to participate in the film-forming process. The zinc ions can form a protective film on the metal surface to improve the corrosion resistance of the metal.

[0038] The inorganic salt accounts for 3% and is used to adjust the ionic strength of the solution or as an auxiliary component. In addition, the addition of sodium chloride can affect the conductivity and film-forming effect of the solution.

[0039] The copper sulfate pentahydrate accounts for 5% and is used to provide copper ions, which may help to enhance the corrosion resistance of the protective film;

[0040] The terpolymer accounts for 5% and is used to improve the stability and performance of the solution;

[0041] The sulfuric acid accounts for 3% and is used to adjust the pH value of the solution. The addition of sulfuric acid can affect the film-forming process and the performance of the protective film.

[0042] The benzotriazole accounts for 4% and, as a corrosion inhibitor, can form a protective film on the metal surface, further improving the anti-corrosion effect of the pre-filming agent.

[0043] The terpolymer is obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate under the action of a crosslinking agent and an initiator.

[0044] Wherein, the solvent of the pre-filming agent is pure water.

[0045] The inorganic salt is sodium chloride.

[0046] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0047] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0048] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0049] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0050] Solution A (control group) and solution B (experimental group) were prepared according to the above steps, wherein solution B contained all reagents and solution A contained all reagents except benzotriazole. All experiments were repeated 3 times and the results were expressed as mean ± standard deviation.

[0051] Instrument: SCRCC-Ⅲ open rotating coupon corrosion tester, type I 20# carbon steel coupon.

[0052] Water samples: The water used in the experiment was tap water. According to the experimental requirements, the calcium concentration of the water was supplemented to 90-100 mg / L, and the pH of the water sample was adjusted to 7-9.

[0053] The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto, with a concentration of 300mg / L; the beakers were placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48 hours, with the temperature set to 20°C. After the experiment, the corrosion resistance time of the film was tested using copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time. Specific embodiment 2:

[0055] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0056] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0057] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0058] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0059] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0060] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0061] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1. The same instrument (SCRCC-Ⅲ open type rotating coupon corrosion tester) and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto. The concentration of the pre-filming agent was 500mg / L. The beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48h. The temperature was set to 20°C. After the experiment, the corrosion resistance time of the film was tested using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time.

[0062] All experiments were repeated 3 times, and the final data were expressed as mean ± standard deviation. Specific embodiment three:

[0064] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0065] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0066] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0067] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0068] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0069] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0070] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1, and the same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto, and the concentration of the pre-filming agent was 700mg / L; the beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48h, and the temperature was set to 20°C. After the experiment, the corrosion resistance time of the film was detected using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time.

[0071] result:

[0072] The results obtained in Examples 1-3 are shown in Table 1:

[0073]

[0074]

[0075] The pre-filming agent shows a uniform blue-green halo in appearance. From the data in Table 1, it can be seen that the reaction time of the film produced by the pre-filming agent to the copper sulfate standard titration solution at 20°C generally meets the requirements of HG / T3778-2005 (t≥10s). The color change time of pre-filming agent B (experimental group) is significantly higher than that of pre-filming agent A (control group), indicating that the addition of benzotriazole significantly improves the overall corrosion resistance of the pre-filming agent. In addition, when the concentration of the pre-filming agent reaches 500 mg / L, the pre-filming effect is better, and the increase in the pre-filming effect is not significant with the increase in concentration. Specific embodiment four:

[0077] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0078] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0079] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0080] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0081] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0082] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0083] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1. The same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto. The concentration of the pre-filming agent was 300mg / L. The beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48 hours. The temperature was set to 30°C. After the experiment, the corrosion resistance time of the film was tested using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time. Specific embodiment five:

[0085] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0086] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0087] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0088] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0089] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0090] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0091] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1, and the same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto, and the concentration of the pre-filming agent was 500mg / L; the beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48h, and the temperature was set to 30°C. After the experiment, the corrosion resistance time of the film was detected using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time. Specific embodiment six:

[0093] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0094] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0095] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0096] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0097] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0098] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0099] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1, and the same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto, and the concentration of the pre-filming agent was 700mg / L; the beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48h, and the temperature was set to 30°C. After the experiment, the corrosion resistance time of the film was detected using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time.

[0100] Results: The results obtained in Examples 4-6 are shown in Table 2:

[0101]

[0102] From the appearance, the pre-filming shows a uniform blue-green halo. From the data in Table 2, it can be seen that under the condition of 30°C, the reaction time of the film to the copper sulfate standard titration solution generally meets the requirements of HG / T3778-2005 (t≥10s). The color change time of pre-filming agent B (experimental group) is significantly higher than that of pre-filming agent A (control group), indicating that after the addition of benzotriazole, the overall corrosion resistance of the pre-filming agent is significantly improved. In addition, when the concentration of the pre-filming agent increases from 300mg / L to 500mg / L, the pre-filming effect is significantly improved. With the further increase in concentration, the increase in the pre-filming effect is not significant. Compared with 20°C, the color change time of each group is almost the same, and the difference is not significant. Specific embodiment seven:

[0104] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0105] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0106] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0107] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0108] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0109] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0110] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1. The same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto. The concentration of the pre-filming agent was 300mg / L. The beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48 hours. The temperature was set to 40°C. After the experiment, the corrosion resistance time of the film was tested using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time. Specific embodiment eight:

[0112] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0113] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0114] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0115] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0116] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0117] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0118] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1, and the same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto, and the concentration of the pre-filming agent was 500mg / L; the beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48h, and the temperature was set to 40°C. After the experiment, the corrosion resistance time of the film was detected using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time. Specific embodiment nine:

[0120] A circulating cooling water non-phosphorus pre-filming agent and a preparation method thereof, wherein the reagents for preparing the pre-filming agent include sodium gluconate (CP), zinc sulfate heptahydrate (CP), sodium chloride (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR), and benzotriazole (AR), wherein the specific dosage of each reagent is as follows:

[0121] Sodium gluconate (20%), zinc sulfate heptahydrate (10%), sodium chloride (3%), copper sulfate pentahydrate (5%), terpolymer (obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate in the presence of a crosslinking agent and an initiator) (5%), sulfuric acid (3%), benzotriazole (4%), and pure water (50%).

[0122] A method for preparing a circulating cooling water phosphorus-free pre-filming agent, the specific steps are as follows:

[0123] S1 Weighing reagents: Determine the best dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, sodium chloride, copper sulfate pentahydrate, terpolymer, and benzotriazole in turn, add them to a beaker, add water, use a magnetic stirrer, stir and dissolve completely for later use;

[0124] S2 Prepare sulfuric acid solution: In a fume hood, take a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly, and wait for the sulfuric acid solution to cool to room temperature for use;

[0125] S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

[0126] Solution A (control group) and solution B (experimental group) were prepared according to the method and steps of Example 1, and the same instrument and the same batch of water samples were used. The water samples were added to 2L beakers, and then a certain amount of pre-filming agent was added thereto, and the concentration of the pre-filming agent was 700mg / L; the beaker was placed in a rotating coupon corrosion tester with a carbon steel test piece, and rotated for 48h, and the temperature was set to 40°C. After the experiment, the corrosion resistance time of the film was detected using a copper sulfate standard titration solution, and the quality of the film was evaluated by the corrosion resistance time.

[0127] Results: The results obtained in Examples 7-9 are shown in Table 3:

[0128]

[0129] The pre-filming agent has a uniform blue-green halo in appearance. The data in Table 3 show that the reaction time of the film to the copper sulfate standard titration solution at 40°C generally meets the requirements of HG / T3778-2005 (t≥10s). The discoloration time of pre-filming agent B (experimental group) is significantly higher than that of pre-filming agent A (control group), indicating that the corrosion resistance of the pre-filming agent is significantly improved in the experimental group with the addition of benzotriazole. When the concentration of the pre-filming agent increases from 300 mg / L to 500 mg / L, the pre-filming effect is significantly improved. With the further increase of the concentration, the increase of the pre-filming effect is not significant.

[0130] Results and discussion: By comparing the color change time of the control group A and the experimental group B, it can be clearly seen that the addition of benzotriazole significantly prolonged the color change time, which strongly proves from the side that the addition of benzotriazole has a significant improvement effect on the corrosion resistance of the original phosphorus-free pre-filming agent. Further observations show that when the concentration of the pre-filming agent reaches 500 mg / L, its pre-filming effect is particularly significant, which not only ensures excellent anti-corrosion performance, but also effectively avoids excessive use of the pre-filming agent and realizes efficient utilization of resources. In addition, the application of the pre-filming agent shows high adaptability to the ambient temperature, and its effective temperature range is relatively wide. Specifically, in the temperature range of 20°C to 40°C, the pre-filming agent can exert a good pre-filming effect without strict control of the ambient temperature, which further broadens its scope and convenience in practical applications.

[0131] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A phosphorus-free pre-filming agent for circulating cooling water, characterized in that: The pre-filming agent includes sodium gluconate (CP), zinc sulfate heptahydrate (CP), inorganic salt (AR), copper sulfate pentahydrate (AR), terpolymer (LR), sulfuric acid (AR) and benzotriazole (AR), wherein: The sodium gluconate accounts for 10% to 30% and is used to improve the wettability and spreadability of the solution and promote the film-forming process; The zinc sulfate heptahydrate accounts for 5% to 15% and is used to provide zinc ions to participate in the film-forming process; The inorganic salt accounts for 1% to 5% and is used to adjust the ionic strength of the solution or as an auxiliary component; The copper sulfate pentahydrate accounts for 1% to 5% and is used to provide copper ions; The terpolymer accounts for 2% to 10% and is used to improve the stability and performance of the solution; The sulfuric acid accounts for 1% to 3% and is used to adjust the pH value of the solution; The benzotriazole accounts for 0.5% to 5% and serves as a corrosion inhibitor.

2. A circulating cooling water non-phosphorus pre-filming agent according to claim 1, characterized in that: The terpolymer can be obtained by thermal polymerization of 2-phenoxyethyl acrylate, methacrylate and acrylate under the action of a crosslinking agent and an initiator.

3. A circulating cooling water non-phosphorus pre-filming agent according to claim 1, characterized in that: The solvent of the pre-filming agent is pure water.

4. The phosphorus-free pre-filming agent for circulating cooling water according to claim 1, characterized in that: The inorganic salt is one of sodium chloride, potassium chloride or sodium sulfate.

5. The phosphorus-free pre-filming agent for circulating cooling water according to claim 1, characterized in that: The pre-filming effect of the pre-filming agent is tested by: using a carbon steel coupon and testing with a coupon corrosion tester; Among them, the inspection process is carried out in the temperature range of 20 to 40°C; The test duration is 24 to 48 hours.

6. A method for preparing the phosphorus-free pre-filming agent for circulating cooling water according to claim 1, characterized in that: The specific steps are as follows: S1 Weighing reagents: Determine the optimal dosage according to the proportion of each reagent, use an electronic balance to weigh sodium gluconate, zinc sulfate heptahydrate, inorganic salt, copper sulfate pentahydrate, terpolymer, and benzotriazole in sequence, pour into a beaker, add water and stir to dissolve; S2 prepares sulfuric acid solution: absorb a certain amount of concentrated sulfuric acid solution, dissolve it in pure water, stir evenly and set aside; S3 Volume adjustment: Use a glass rod to transfer the required solution from the beaker to a volumetric flask of a certain size, rinse the wall of the beaker, and finally use pure water to adjust the volume to the scale line.

7. The method for preparing the phosphorus-free pre-filming agent for circulating cooling water according to claim 6, characterized in that: In step S1, a magnetic stirrer is used as an auxiliary tool to perform stirring operation at room temperature. After sufficient stirring for a certain period of time, it is ensured that a variety of solid medicines can be evenly dissolved to form a uniform solution.

8. The method for preparing the phosphorus-free pre-filming agent for circulating cooling water according to claim 6, characterized in that: In step S2, after the concentrated sulfuric acid is prepared into a solution, the sulfuric acid solution is waited to cool naturally to room temperature before the subsequent transfer operation is performed to ensure the safety of the operation.

9. The method for preparing the circulating cooling water non-phosphorus pre-filming agent according to claim 6, characterized in that: In step S3, in order to detect the optimal concentration of the pre-filming agent, it is necessary to configure it into solutions of different concentrations, including 300 mg / L, 500 mg / L, and 700 mg / L, and then put these solutions of different concentrations into the pre-filming effect inspection test. By observing and analyzing the test results, the optimal concentration of the pre-filming agent is determined.

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