A method for preventing scale formation on the surface of a galvanized iron pipe

Abstract

The application discloses a method for preventing scale on the surface of a galvanized iron pipe, and belongs to the field of pipe surface treatment, which is used for solving the problem that the pipe surface is easy to scale in the industrial production process, and further improving the mass transfer and heat transfer efficiency in the production process and delaying the pipe corrosion. The method comprises the following steps: forming zinc oxide nanorods on the surface of the zinc plating layer of the galvanized iron pipe through surface reaction, carrying out hydrophobic / lipophilic treatment on the zinc oxide nanorods, and then filling water-immiscible oil into the hydrophobic / lipophilic surface of the galvanized iron pipe, so as to realize the isolation between the water phase in the pipe and the surface of the galvanized iron pipe, prevent the scale in the water phase from depositing on the pipe surface, and achieve the purpose of scale prevention. The method for preventing scale on the surface of the galvanized iron pipe has the advantages of simple process, low cost, stable effect and the like, and is widely applicable to the scale prevention treatment of pipes required in industrial production.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment, and specifically relates to a method for preventing scale buildup on the surface of galvanized iron pipes. Background Technology

[0002] In industrial production processes, scale buildup on pipe surfaces not only reduces heat transfer efficiency and increases energy consumption but also accelerates corrosion. Traditional scale prevention technologies mainly include physical and chemical methods. However, current anti-scaling technologies still face many challenges. For example, physical scale prevention methods may damage pipes, while chemical scale inhibitors may pollute the environment. Therefore, to achieve more stable and efficient scale prevention in industrial production processes, it is necessary to research and develop more effective anti-scaling technologies.

[0003] To address the above problems, this invention discloses a method for preventing scale buildup on the surface of galvanized iron pipes. By sequentially performing oxidation treatment, hydrophobic / oleophilic treatment, and oil filling treatment on the galvanized layer on the surface of the galvanized iron pipe, a liquid oil phase lubricating layer is prepared on the surface of the galvanized iron pipe. This isolates the water phase in the pipe from contact with the pipe surface, thereby preventing scale buildup on the pipe surface and achieving the purpose of preventing scale deposition. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preventing scale buildup on the surface of galvanized iron pipes. The galvanized layer on the surface of the galvanized iron pipe is subjected to a series of treatments: oxidation, hydrophobic / oleophilic treatment, and oil filling. This creates a liquid oil-phase lubricating layer on the surface of the galvanized iron pipe, isolating the water phase in the pipe from contact with the pipe surface, thereby preventing scale buildup and achieving the goal of preventing scale deposition.

[0005] To achieve the above objectives, the present invention provides a method for preventing scale buildup on the surface of galvanized iron pipes, comprising the following steps:

[0006] (1) Zinc oxide nanorods are formed on the surface of the zinc coating of galvanized iron pipes.

[0007] The formation of zinc oxide nanorods on the surface of the zinc coating of galvanized iron pipes can be achieved through hydrothermal oxidation or electrolysis.

[0008] Hydrothermal oxidation method: The galvanized iron pipe is placed in a high-pressure reactor, and water is used as the reaction medium. The hydrothermal oxidation reaction is carried out under certain temperature and pressure to oxidize the surface of the galvanized iron pipe and form zinc oxide nanorods.

[0009] The hydrothermal oxidation reaction is carried out at a temperature of 50℃ to 300℃ and a pressure of 0.2MPa to 20MPa.

[0010] Electrolysis method: A galvanized iron pipe is placed in an electrolyte as the cathode, and zinc oxide nanorods are formed on the surface of the galvanized iron pipe through electrolysis.

[0011] Among them: the electrolyte contains Zn 2+ Aqueous solution containing Zn 2+ Methanol solution or a mixture thereof, Zn 2+ The concentration is 0.01mM to 5M, the electrolysis time is 1 minute to 10 hours, the potential of the galvanized iron pipe as the cathode is -5V to -0.1V, and the electrolysis temperature is 10℃ to 100℃.

[0012] (2) Hydrophobic / oleophilic treatment of the zinc coating on the surface of galvanized iron pipe

[0013] The galvanized iron pipe treated in step (1) is reacted with organosilane under certain conditions to form a hydrophobic / oleophilic layer on the surface of the galvanized iron pipe, so that the wettability of the surface of the galvanized iron pipe is hydrophobic and oleophilic.

[0014] Wherein: the organosilane is alkyltrimethoxysilane, alkyltriethoxysilane or a mixture thereof; the organosilane can be a solution formed by dissolving in ethanol, methanol or a mixture thereof, with a concentration of 0.0001wt% to 10wt%; or it can be a gaseous organosilane with a partial pressure of 1Pa to 1MPa; the reaction temperature between galvanized iron pipe and organosilane is 10℃ to 180℃, and the reaction time between galvanized iron pipe and organosilane is 5 minutes to 3 days.

[0015] (3) Oil filling treatment of the galvanized layer on the surface of galvanized iron pipe

[0016] A liquid oil phase that is immiscible with water is injected into the surface of the hydrophobic / oleophilic galvanized iron pipe after step (2) treatment, and a liquid oil phase lubrication layer is prepared on the surface of the galvanized iron pipe to isolate the water phase in the pipe from the pipe surface, thus creating a galvanized iron pipe surface that is free from scale deposition.

[0017] Among them, the thickness of the liquid film after the water-immiscible liquid oil phase is injected into the surface of the hydrophobic / oleophilic galvanized iron pipe is 1μm to 3mm.

[0018] The beneficial effects of this invention are:

[0019] 1. The anti-scaling method for galvanized iron pipes provided by this invention results in stable anti-scaling performance of the galvanized iron pipe surface, achieving a long-term anti-scaling effect.

[0020] 2. The method for preventing scale buildup on the surface of galvanized iron pipes provided by this invention has the advantages of simple process, low cost and little environmental impact, and is widely applicable to the anti-scaling treatment of galvanized iron pipe surfaces. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process for treating galvanized iron pipes using the method for preventing scale buildup on the surface of galvanized iron pipes provided by the present invention.

[0022] Figure 2(a) A scanning electron microscope image of the surface of an untreated galvanized iron pipe. Figure 2 (b) is a scanning electron microscope image of the oxidized galvanized iron pipe surface.

[0023] Figure 3 Images showing the contact angle measurements of water droplets and oil droplets on the surface of a galvanized iron pipe after hydrophobic / oleophilic treatment.

[0024] Figure 4 The experimental results evaluate the anti-scaling performance of the galvanized iron pipe surface after treatment with the anti-scaling method provided by the present invention. Detailed Implementation

[0025] Example 1

[0026] Oxidation treatment of the zinc coating on the surface of galvanized iron pipe: A galvanized iron pipe with a length of 5 cm, an inner diameter of 2 cm, and an outer diameter of 2.5 cm was cleaned with ethanol and placed in a reaction vessel. 150 mL of deionized water was added to the reaction vessel. The reaction vessel was sealed and heated at 120℃ for 6 hours. After the reaction was completed, the pipe sample was collected, cleaned, and dried. The microstructure of zinc oxide nanorods on the surface of the oxidized galvanized iron pipe is shown in the figure. Figure 2 As shown in (b).

[0027] Hydrophobic / Oleophilic Treatment of the Zinc Coating on the Surface of Galvanized Iron Pipes: The oxidized galvanized iron pipes treated in the previous step are immersed in a 0.3 wt% hexyltrimethoxysilane atmosphere and kept at 100°C for 3 hours to complete the hydrophobic / oleophilic treatment of the galvanized iron pipe surface. Then, the galvanized iron pipe sample is taken out, and the contact angles of the oil phase and water phase on the surface are measured. Figure 3 As shown, the contact angle measurement results are 156° for water droplets and 0° for oil droplets (dodecane), indicating a hydrophobic / oleophilic surface.

[0028] Oil filling treatment of the zinc coating on the surface of galvanized iron pipe: 0.3 mL of dodecane (liquid oil phase) is added to the inner surface of the hydrophobic / oleophilic galvanized iron pipe obtained in the previous step to make the surface oil film thickness about 0.1 mm, thus obtaining a galvanized iron pipe with oil filling and waterproof scale deposition.

[0029] The final oil-filled galvanized iron pipe samples were placed in heated brine to evaluate their anti-scaling performance, and compared with the anti-scaling performance of untreated galvanized iron pipes. Figure 4 ).

[0030] Example 2

[0031] Electrochemical treatment of the zinc coating on the surface of galvanized iron pipe: A galvanized iron pipe with a length of 5cm, an inner diameter of 2cm, and an outer diameter of 2.5cm was taken, cleaned with ethanol, and placed in an electrolytic support. A platinum electrode was used as the anode, the galvanized iron pipe as the cathode, and a saturated calomel electrode as the reference electrode. Zn(NO3)2 aqueous solution was used as the electrolyte, KNO3 as the supporting electrolyte, Zn(NO3)2 concentration was 3mM and KNO3 concentration was 50mM. A constant voltage mode was adopted, the cathode voltage was controlled at -0.9V, and the electrolysis time was 1h. After the reaction was completed, it was thoroughly cleaned with deionized water and ethanol to remove residues, and then dried in air at room temperature.

[0032] Hydrophobic treatment of the zinc coating on the surface of galvanized iron pipe: The oxidized galvanized iron pipe after the previous step is placed in a methanol solution of 0.3wt% propyltriethoxysilane and reacted at 70℃ for 3 hours to complete the hydrophobic / oleophilic treatment of the galvanized iron pipe surface.

[0033] Oil filling treatment of the galvanized layer on the surface of galvanized iron pipe: 0.6 mL of paraffin oil (liquid oil phase) is added to the inner surface of the hydrophobic galvanized iron pipe obtained in the previous step, so that the surface oil film thickness is about 0.2 mm, and an oil-filled galvanized iron pipe with a waterproof scale deposit is obtained.

[0034] Example 3

[0035] Oxidation treatment of the galvanized layer on the surface of galvanized iron pipe: Take a galvanized iron pipe with a length of 5cm, an inner diameter of 2cm, and an outer diameter of 2.5cm. After cleaning with ethanol, place it in a reaction vessel and add 150mL of deionized water. Seal the reaction vessel and heat at 180℃ for 10 hours. After the reaction is complete, rinse repeatedly with deionized water and then dry at 50-60℃ for 4 hours.

[0036] Hydrophobic treatment of the zinc coating on the surface of galvanized iron pipe: The oxidized galvanized iron pipe after the previous step is placed in an ethanol solution of 0.5 wt% methyltrimethoxysilane and reacted at 70°C for 5 hours to complete the hydrophobic / oleophilic treatment of the galvanized iron pipe surface.

[0037] Oil filling treatment of the galvanized layer on the surface of galvanized iron pipe: 0.3 mL of corn oil (liquid oil phase) is added to the inner surface of the hydrophobic galvanized iron pipe obtained in the previous step, so that the surface oil film thickness is about 0.1 mm, and an oil-filled galvanized iron pipe with a waterproof scale deposit is obtained.

[0038] Although specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A method for preventing scale buildup on the surface of galvanized iron pipes, characterized in that, The method includes the following steps: (1) The zinc coating on the surface of the galvanized iron pipe is subjected to surface treatment to produce a galvanized iron pipe with zinc oxide nanorods on the surface; the surface treatment method is hydrothermal oxidation or electrochemical deposition. In the hydrothermal oxidation method, the reaction is carried out in a closed reaction vessel, using water as the reaction medium, with a reaction temperature of 50℃~300℃ and a reaction pressure of 0.2MPa~20MPa; in the electrochemical deposition method, the electrolyte is Zn. 2+ Aqueous solution, Zn 2+ Methanol solution or a mixture thereof, Zn 2+ The concentration is 0.01mM to 5M, the electrolysis time is 1 minute to 10 hours, the galvanized iron pipe is the cathode, the potential is -5V to -0.1V, and the electrolysis temperature is 10℃ to 100℃. (2) The zinc oxide nanorods on the surface of the galvanized iron pipe after step (1) are modified by using an organosilane to make a surface hydrophobic / oleophilic galvanized iron pipe; the organosilane is alkyltrimethoxysilane, alkyltriethoxysilane or a mixture thereof; the reaction temperature of the modification treatment is 10℃~180℃, and the reaction time is 5 minutes~3 days; When the organosilane is used in solution form, it is soluble in ethanol, methanol, or a mixture thereof, with a concentration of 0.0001 wt% to 10 wt%; when used in gaseous form, its partial pressure is 1 Pa to 1 MPa. (3) A liquid oil phase that is immiscible with water is injected into the surface of the hydrophobic / oleophilic galvanized iron pipe after step (2) to form a stable oil layer; the thickness of the liquid film formed after the liquid oil phase is injected is 1μm to 3mm.

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