Preparation method and application of super-oleophobic anticorrosive coating suitable for crude oil storage tank

Abstract

A method for preparing and applying an oil-repellent corrosion-resistant coating suitable for crude oil storage tanks, the method comprising modifying the surface of silica with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, combining the modified silica with an epoxy resin and PTFE to form a binder, and spraying the binder onto the surface of carbon steel to form an oil-repellent coating. The coating has excellent liquid repellency for both water and crude oil, with a water contact angle of 164.1°, a water roll-off angle of 1.1°, a crude oil contact angle of 172.1°, and a crude oil roll-off angle of 2.5°. The coating remains dry after being immersed in crude oil for 120 days. The oil-repellent coating has stable pores on its surface, which act as an anti-adhesion barrier to prevent the coating from adhering to crude oil. The oil-repellent coating can be applied to crude oil storage tanks to effectively prevent the emission of volatile organic compounds. The method has a wide range of applications, is simple to operate, and effectively reduces economic losses caused by crude oil loss and environmental pollution caused by crude oil evaporation.

Description

Technical Field

[0001] This invention relates to the fields of materials technology and resource environment, and in particular to a method for preparing and applying a superoleophobic anti-corrosion coating suitable for crude oil storage tanks. Background Technology

[0002] Volatile organic compounds (VOCs) in the air can have serious adverse effects on human health and the environment. VOCs are released throughout the entire process from crude oil extraction to refining, making refineries one of the major sources of VOC emissions into the environment. The composition of VOCs released from crude oil is very complex, contributing to severe air pollution problems, and resulting in a significant economic waste of valuable crude oil resources released into the atmosphere each year due to volatilization. Among the various emission sources within refineries, crude oil storage tanks emit a large amount of VOCs, and studies have found that the emission index of crude oil is higher than most existing research, with crude oil adhering to the inner walls of storage tanks being one of the reasons for the high VOC volatilization.

[0003] VOC emissions can be reduced through various methods, such as adsorption, catalytic oxidation, and membrane separation. While these methods are effective, they are typically accompanied by high operating costs and energy consumption. Some petrochemical companies use direct combustion, exacerbating the greenhouse effect. Therefore, there is an urgent need to develop cost-effective and environmentally friendly alternatives to effectively address the challenge of VOC emissions. Summary of the Invention

[0004] The purpose of this invention is to solve the aforementioned problems in the prior art and provide a method for preparing and applying a superoleophobic anti-corrosion coating suitable for crude oil storage tanks. This invention, by developing a coating with superoleophobic properties, can reduce crude oil adhesion to the inner wall of the storage tank, thereby effectively reducing VOC emissions from crude oil storage tanks. The method of this invention is easy to operate and can effectively save energy and reduce environmental pollution.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a superoleophobic and anti-corrosion coating suitable for crude oil storage tanks includes the following steps:

[0007] 1) Preparation of suspension: Grafting of silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane in an alkaline solution using a silane coupling agent; the alkaline solution includes ammonia and ethanol; the ethanol is anhydrous ethanol;

[0008] 2) Preparation of adhesive: The adhesive comprises a mixture of PTFE and epoxy resin;

[0009] 3) First, spray an adhesive onto the inner wall of the crude oil storage tank, then spray a suspension. After curing, an oleophobic and anti-corrosion coating is formed.

[0010] In step 1), the mass percentage of the silica added in the suspension to ethanol is 1.0wt% to 5.0wt%.

[0011] In step 1), the volume percentage of the 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane added in the suspension to ethanol is 2.0V / V% to 10.0V / V%.

[0012] In step 1), the volume percentage of the silane coupling agent added in the suspension to ethanol is 0.5V / V% to 5.0V / V%.

[0013] In step 1), the mass percentage of the ammonia (NH3) contained in the ammonia water is 25% to 28%.

[0014] In step 2), the mass ratio of PTFE to epoxy resin is not higher than 50.0wt%.

[0015] In step 2), the adhesive further comprises a curing agent.

[0016] The super-oleophobic anticorrosive coating is used for spraying on the inner wall of a crude oil storage tank, and the super-oleophobic coating effectively resists crude oil adhesion and reduces a large amount of VOCs generated due to crude oil adhesion. Preferably, the VOCs are non-methane total hydrocarbons; the test method of the non-methane total hydrocarbons is testing by a hydrogen flame ionization detector of a gas chromatograph-mass spectrometer.

[0017] Specifically, spraying is performed by using an airbrush, the air pressure of the airbrush is 0.1 to 1.0MPa, and the spraying distance is 10 to 40cm.

[0018] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0019] The present application first applies the super-oleophobic coating to the inner wall of a crude oil storage tank, which can maximize the reduction of the contact between crude oil and the tank wall, and this method can achieve efficient resistance to crude oil adhesion and thus reduce the release of volatile organic compounds; the chemical reagents required by this method are easy to obtain, the operation is simple, the application value is high, it is easy to popularize, and it is suitable for large-scale industrial application. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Fig. 3 is a diagram showing the effect of PTFE and epoxy resin with different mass ratios on the super-oleophobicity of the coating;

[0021] Figure 2 Fig. 5 is a diagram showing the effect of SiO2 and acetone solution in the suspension at different mass percentages on the super-oleophobicity of the coating;

[0022] Figure 3 Fig. 7 is a diagram showing the effect of the super-oleophobic coating on the hydrophobicity and oleophobicity of different liquids.

[0023] Figure 4 Figure 4 is a graph showing the effect of different days of immersion in crude oil on the superoleophobic effect of the coating;

[0024] Figure 5 Figure 5 is a graph showing the crude oil anti-adhesion effect of carbon steel sheets, commercial coating and superoleophobic coating; wherein the carbon steel sheet represents a carbon steel sheet without a sprayed coating, the commercial coating represents a carbon steel sheet sprayed with a commercial coating, and the superoleophobic coating represents a carbon steel sheet sprayed with a superoleophobic coating;

[0025] Figure 6 Figure 6 is a graph showing the VOCs volatilization after the carbon steel sheets, commercial coating and superoleophobic coating are immersed in crude oil; wherein the carbon steel sheet represents a carbon steel sheet without a sprayed coating, the commercial coating represents a carbon steel sheet sprayed with a commercial coating, and the superoleophobic coating represents a carbon steel sheet sprayed with a superoleophobic coating. DETAILED DESCRIPTION

[0026] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clear, explicit, the present application will be further described in detail below in combination with the drawings and examples.

[0027] Example 1

[0028] Effect of different mass ratios of PTFE and epoxy resin on the superoleophobic effect of the coating

[0029] Suspension: 0.5 g of silica and 6 mL of ammonia water were added to 40 mL of an ethanol solution, stirred for 30 min, 0.4 mL of a silane coupling agent and 1.2 mL of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane were added, and the reaction was carried out for 4 h. After the reaction was completed, centrifugation was performed, and ethanol washing was performed 3 times. Then, 10 mL of an acetone solution was added, and the mixture was uniformly dispersed and reserved.

[0030] Adhesive: 2.5 g of an epoxy resin was dispersed in 15 mL of an acetone solution, and ultrasonic treatment was performed until the dispersion was uniform. Then, 0 g, 0.25 g, 0.50 g, 0.75 g, 1.0 g, and 1.25 g of PTFE powder were added, respectively, to prepare 6 kinds of adhesives with different ratios. Ultrasonic treatment was performed for 1 h until the dispersion was uniform, and 0.625 g of a curing agent was added and reserved; the curing agent was a phenolic amine (PAA) epoxy curing agent.

[0031] Spraying: the air pressure of an air compressor and a spray gun was adjusted, and the spraying distance was controlled to be 20 cm. Spraying was performed on a carbon steel sheet, specifically, the adhesive was sprayed first, and then the suspension was sprayed. Room temperature curing was performed for 24 h. The contact angle and the roll-off angle of the coating with hexadecane were tested by a contact angle instrument, and the results are shown in Table 1. Figure 1 .

[0032] Figure 1It is shown that when the PTFE dosage is 1.0 g, i.e. the mass ratio of PTFE and epoxy resin is 40%, the contact angle of the coating to hexadecane is the highest and the rolling angle is the lowest, i.e. the oil-repellent effect of the coating is the best.

[0033] Example 2

[0034] Effect of SiO2 and acetone solution in the suspension on the super-oleophobic effect of the coating at different mass percentages

[0035] Example 1 is repeated with the following differences: the PTFE dosage is 1.0 g, and the dosage of the acetone solution in the suspension is 5 mL, 10 mL, 20 mL and 30 mL respectively, corresponding to the mass percentages of SiO2 and acetone solution of 12.74%, 6.37%, 3.18% and 2.12% respectively. The results are shown in Table 2. Figure 2 .

[0036] Figure 2 It is shown that when the dosage of the acetone solution in the suspension is 10 mL, i.e. the mass percentage of SiO2 and acetone solution is 6.37%, the contact angle of the coating to hexadecane is the highest and the rolling angle is the lowest, i.e. the oil-repellent effect of the coating is the best.

[0037] Example 3

[0038] Super-oleophobic coating and its hydrophobic and oleophobic effects on different liquids

[0039] Example 1 is repeated with the following differences: the PTFE dosage is 1.0 g, and the dosage of the acetone solution in the suspension is 5 mL, 10 mL, 20 mL and 30 mL respectively, corresponding to the mass percentages of SiO2 and acetone solution of 12.74%, 6.37%, 3.18% and 2.12% respectively. The results are shown in Table 2. Figure 3 .

[0040] Figure 3 It is shown that the super-oleophobic coating has very good liquid-repellent effect on water, crude oil and various liquids.

[0041] Example 4

[0042] Effect of the super-oleophobic coating on the oil-repellent effect after being immersed in crude oil for different days

[0043] Example 1 is repeated with the following differences: the PTFE dosage is 1.0 g, and the dosage of the acetone solution in the suspension is 5 mL, 10 mL, 20 mL and 30 mL respectively, corresponding to the mass percentages of SiO2 and acetone solution of 12.74%, 6.37%, 3.18% and 2.12% respectively. The results are shown in Table 2. Figure 4 .

[0044] Figure 4It shows that the contact angle of the coating to crude oil is still higher than 150 degrees after 120 days of crude oil immersion, and the rolling angle of the coating to crude oil always remains near 20 degrees, indicating that the coating has excellent oil-repellent properties and resistance to crude oil corrosion.

[0045] Example 5

[0046] Comparison of the anti-adhesion effect of carbon steel sheets to crude oil with commercial coating and super oil-repellent coating

[0047] First, three carbon steel sheets were cleaned with ethanol and sanded with sandpaper to remove surface oil and impurities; then, one of the carbon steel sheets was not sprayed with any coating; one of the carbon steel sheets was sprayed with a commercial coating, which was a heavy-duty corrosion-resistant coating suitable for the inner wall of a crude oil storage tank, specifically purchased from Balian heavy-duty corrosion-resistant special industrial coating; one of the carbon steel sheets was sprayed with the super oil-repellent coating of Example 1, and the dosage of PTFE was 1.0 g.

[0048] The three carbon steel sheets treated above were immersed in crude oil for 30 minutes respectively. After taking them out of the crude oil, the crude oil on the back was wiped off and cleaned with ethanol and acetone, the front was attached to a nitrile rubber, and a 100g weight was placed to simulate the scraping of the actual crude oil storage tank outer floating roof on the inner wall. After sliding a certain distance, it was photographed. At the same time, the contact angle of the coating to crude oil was tested by a contact angle instrument, and the results are shown in Table 2. Figure 5 .

[0049] Figure 5 It shows that compared with carbon steel sheets without coating and commercial coating, the super oil-repellent coating has good resistance to crude oil adhesion.

[0050] Example 6

[0051] Comparison of the VOCs volatilization of carbon steel sheets with commercial coating and super oil-repellent coating after immersion in crude oil

[0052] Repeat Example 5, and place the three carbon steel sheets in the same size of airtight device respectively, and extract all the gas in the device at 0h, 2h, 4h, 8h, 24h, 48h and 72h into a 30L gas bag to test the concentration of non-methane total hydrocarbons, and the results after calculation are shown in Table 3. Figure 6 .

[0053] Figure 6 It shows that compared with carbon steel sheets without coating and commercial coating, the super oil-repellent coating can reduce the volatilization of non-methane total hydrocarbons by 88.3% and 86.7% respectively within 72h, indicating that the super oil-repellent coating can effectively reduce the loss of crude oil and the generation of volatile organic compounds.

[0054] The superoleophobic coating has excellent liquid protection performance on water and crude oil, the water contact angle is 164.1°, the rolling angle is 1.1°, the crude oil contact angle is 172.1°, and the rolling angle is 2.5°. The coating is still not wetted after being immersed in crude oil for 120 days. The surface of the superoleophobic coating has stable pores, which can act as an anti-adhesion isolation barrier to prevent the coating from adhering to the crude oil. The application of the superoleophobic coating to the crude oil storage tank can effectively prevent the emission of volatile organic compounds. The method has wide application range, simple operation, and can effectively reduce the economic loss caused by the loss of crude oil and the environmental pollution caused by the volatilization of crude oil.

Claims

1. A method for preparing a superoleophobic anti-corrosion coating suitable for crude oil storage tanks, characterized in that, Includes the following steps: 1) Suspension: Add 0.5 g of silica and 6 mL of ammonia to 40 mL of ethanol solution, stir for 30 min, add 0.4 mL of silane coupling agent and 1.2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, react for 4 h, centrifuge after the reaction is completed, wash 3 times with ethanol, add 10 mL of acetone solution, disperse evenly and set aside. 2) Adhesive: 2.5 g of epoxy resin is dispersed in 15 mL of acetone solution and sonicated until uniformly dispersed. 0.75 g or 1.0 g of PTFE powder is added and sonicated for 1 hour until uniformly dispersed. 0.625 g of curing agent is added for later use. The curing agent is a phenolic amine epoxy curing agent. 3) Spraying: Adjust the air pressure of the air compressor and spray gun, control the spraying distance to 20 cm, and spray onto the carbon steel sheet. Specifically, first spray the adhesive and then spray the suspension. Cure at room temperature for 24 hours. After curing, an oleophobic and anti-corrosion coating is formed.

2. A superoleophobic anti-corrosion coating suitable for crude oil storage tanks prepared by the method of claim 1.

3. The application of the superoleophobic anti-corrosion coating for crude oil storage tanks as described in claim 2, characterized in that: It is used to spray on the inner wall of crude oil storage tanks to achieve anti-adhesion of crude oil and reduce the volatilization of VOCs.

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