Nanometer container with corrosion inhibitor releasing and emulsifying capacity, preparation method and application

Abstract

The invention discloses a nanometer container with corrosion inhibitor releasing and emulsifying capacity, a preparation method and application, and relates to the technical field of material corrosion prevention. The preparation method comprises the following steps: by taking tetraethyl orthosilicate as a raw material, preparing HMSNs as a shell layer by adopting a template method under the action of ammonia water and hexadecyl trimethyl ammonium bromide; the preparation method comprises the following steps: loading 2-mercaptobenzothiazole into an HMSNs shell layer by adopting a vacuum loading method to form MBT-coated HMSNs; mBT-coated HMSNs are placed in a buffer solution, sodium dodecyl benzene sulfonate is added into the buffer solution for stirring, then polyethyleneimine is added into a mixture obtained through stirring for a reaction, MBT-coated HMSNs-coated PEI is obtained, 1, 2-epoxy octadecane is grafted to a PEI layer of the MBT-coated HMSNs-coated PEI, and the nano container is obtained. The prepared nano container can convey MBT to a corrosion area in an oil well for targeted corrosion inhibition, and meanwhile, deep oil drops can be emulsified to improve the petroleum recovery efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material corrosion prevention, in particular to a nano-container with corrosion inhibitor release and emulsification capacity, a preparation method and application thereof. BACKGROUND

[0002] Metal corrosion is a kind of damage of metal materials in the external environment, which can cause the decrease of mechanical properties such as strength, plasticity and toughness of the materials. In the process of oil exploitation, acidizing operation is used to dissolve the blockage, but acidizing operation exposes the oil well to a harsh corrosive environment, which makes the metal pipeline prone to corrosion.

[0003] In the prior art, there are reports on corrosion inhibitors suitable for oilfield systems: application number 201911221094.4 discloses a compounded low-phosphorus corrosion inhibitor suitable for oilfield systems, which is prepared by mixing polyaspartic acid aqueous solution, polyamino polyether-based methylene phosphonic acid aqueous solution, N-(3-aminopropyl) imidazole aqueous solution, zinc sulfate aqueous solution, etc. in equal volume; wherein the concentration of polyaspartic acid aqueous solution is 10-50 mg / L, the concentration of polyamino polyether-based methylene phosphonic acid aqueous solution is 5-25 mg / L, the concentration of N-(3-aminopropyl) imidazole aqueous solution is 10-50 mg / L, and the concentration of zinc sulfate aqueous solution is 2-10 mg / L.

[0004] Application number 202110867048.2 discloses an imidazoline corrosion inhibitor and its preparation method and application, which comprises oleic acid 40-45%, diethylene triamine 15-18%, benzyl chloride 20-23%, sodium benzoate 2-3%, phenethyl phenol polyoxyethylene ether 3-5%, and water 10-15% by mass percentage. The preparation method comprises the following steps: step one, adding oleic acid and triethylene tetramine for mixing to obtain an imidazoline corrosion inhibitor intermediate; step two, then quaternary amination of the imidazoline intermediate and benzyl chloride to obtain an imidazoline corrosion inhibitor main agent; step three, mixing the obtained imidazoline corrosion inhibitor main agent, sodium benzoate, phenethyl phenol polyoxyethylene ether and water to obtain an imidazoline corrosion inhibitor finished product.

[0005] The above-mentioned research on corrosion inhibitors in the prior art has made certain progress, but there are still problems such as lack of targeting of corrosion inhibitors, irreversible release, inability to simultaneously realize corrosion inhibitor release and emulsification capacity, and poor flowability of crude oil in oil pipelines, resulting in low recovery rate.

[0006] Therefore, the prior art needs to be further improved. SUMMARY

[0007] One of the purposes of the present application is to provide a preparation method of a nano container with corrosion inhibitor release and emulsification capacity, which can deliver MBT to the corrosion area in the oil well for targeted corrosion inhibition, and can emulsify deep oil droplets to improve oil recovery efficiency.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: a preparation method of a nano container with corrosion inhibitor release and emulsification capacity, comprising the following steps: a, using tetraethyl orthosilicate as raw material, HMSNs are prepared as shell layer by template method under the action of ammonia and cetyltrimethylammonium bromide.

[0009] b, MBT is loaded into the HMSNs shell layer by vacuum loading method to form MBT@HMSNs.

[0010] c, an acid buffer solution is prepared, MBT@HMSNs is placed in the buffer solution, sodium dodecylbenzenesulfonate is added and stirred, then PEI is added to the stirred mixture and reacted, after a period of time, glutaraldehyde is added, the amino group in PEI reacts with the aldehyde group in glutaraldehyde to form Schiff base, so that the formed PEI layer is wrapped outside the MBT@HMSNs to form MBT@HMSNs@PEI.

[0011] d, MBT@HMSNs@PEI is dissolved, 1,2-epoxyoctadecane is grafted to its PEI layer at a certain temperature, and the nano container is obtained; the long carbon hydrophobic chain of 1,2-epoxyoctadecane and the hydrophilic amino group of the PEI layer form a "hydrophilic-hydrophobic" binary structure, which can be adsorbed at the oil-water interface to form an oil-in-water emulsion.

[0012] The preparation method of the nano container with corrosion inhibitor release and emulsification capacity, the preparation step of the hollow mesoporous silica is: 0.16g cetyltrimethylammonium bromide, 26mL anhydrous ethanol, 55mL deionized water are mixed and completely dissolved; 1mL tetraethyl orthosilicate is added and stirred for a period of time; then 1mL ammonia is added to the mixed solution with tetraethyl orthosilicate, and the reaction is carried out at room temperature for a period of time to obtain a reaction liquid; the obtained reaction liquid is centrifuged, ultrasonically dispersed and stirred, and then dried to obtain the hollow mesoporous silica.

[0013] In the preparation method of the nano container with corrosion inhibitor release and emulsification capacity, the loading mass of MBT in HMSNs is 25-35%.

[0014] In the above-mentioned method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities, in step c, the pH of the buffer solution is 3-4; the buffer solution is prepared by adding 2.55g of sodium acetate and 10mL of acetic acid to deionized water to obtain 120mL of buffer solution.

[0015] In the above-mentioned method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities, in step c, the mass ratio of MBT@HMSNs to sodium dodecylbenzenesulfonate is 1:1, and the mass ratio of MBT@HMSNs to PEI is 1:0.3; the reaction time for adding PEI is 3-5 h.

[0016] In the above-mentioned method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities, in step c, the mass-to-volume ratio of PEI to glutaraldehyde is 0.01:1 g / mL, and the reaction time after adding glutaraldehyde is 3–5 h.

[0017] In the above-mentioned method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities, in step d, MBT@HMSNs@PEI is added to toluene for dissolution. The dissolution stirring time is 2-4 h, the dissolution temperature is 70-80 °C, and the mass ratio of MBT@HMSNs@PEI to 1,2-epoxyoctadecane is 0.1:3. The grafting reaction time is 10-14 h, and the nanocontainer is dried in a drying oven after the grafting reaction is completed.

[0018] The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities described above, wherein the molecular weight of the polyethyleneimine is 10000.

[0019] Another object of the present invention is to provide a nanocontainer with corrosion inhibitor release and emulsification capabilities, which is prepared by the above-described preparation method. It has an overall spherical structure, with MBT loaded inside a hollow mesoporous silica shell. The mesopores distributed on the hollow mesoporous silica shell enable the entry and exit of MBT and its loading. A PEI layer is wrapped around the hollow mesoporous silica, and 1,2-epoxyoctadecane with a hydrophobic long carbon chain structure is grafted onto the PEI layer.

[0020] Another object of the present invention is to provide an application of the above-mentioned nanocontainer with corrosion inhibitor release and emulsification capabilities, wherein the application is: Step 1, mixing the nanocontainer with the acidification solution and transporting it together to the corrosion area.

[0021] Step 2: When the corrosion zone faces a localized acidic environment, the PEI layer of the nanocontainer is protonated under acidic conditions, carrying a positive charge, and electrostatically adsorbs onto the negatively charged metal corrosion surface, thus achieving targeted delivery of the nanocontainer to the corrosion zone. The acidic environment of the corrosion zone is disrupted. Due to the Schiff base bond formed between glutaraldehyde and PEI, the cross-linking density of the dense PEI layer decreases, and the interaction forces between HMSNs are also disrupted. The mesopores of HMSNs swell under acidic conditions, providing a channel for the release of MBT corrosion inhibitor.

[0022] Step 3: The 1,2-epoxyoctadecane grafted onto the surface of the nanocontainer has a hydrophobic long carbon chain that inserts into the interior of the crude oil droplet, while the PEI layer, after protonation, carries hydrophilic amino groups that are distributed on the outside of the droplet, forming a stable emulsion structure, namely an oil-in-water emulsion. The viscosity of the emulsion is reduced, improving the flowability of crude oil in the pipeline, and at the same time improving the separation efficiency of crude oil and produced fluid.

[0023] The 1,2-epoxyoctadecane of this invention does not have hydrophilic groups and is not an emulsifier. However, grafting it onto PEI can achieve an emulsifying effect. The mechanism is as follows: 1,2-epoxyoctadecane contains long-chain hydrophobic groups and reactive epoxy groups. Due to its hydrophobicity, the long-chain groups are not amphiphilic and cannot be used as emulsifiers. However, its epoxy groups can undergo ring-opening reactions with the amino groups in the PEI layer to achieve chemical grafting. This allows 1,2-epoxyoctadecane to be stably anchored on the surface of the nanocontainer, thus forming an octadecyl alkyl chain as the hydrophobic end exposed to the outside. The PEI layer itself contains a large number of amino groups as hydrophilic ends, forming a "hydrophilic end-hydrophobic end" binary structure on the surface of the nanocontainer, breaking the interfacial tension balance between the oil and water phases. The hydrophobic long carbon chain of 1,2-epoxyoctadecane can insert into the interior of crude oil droplets, weakening the aggregation force between crude oil molecules, turning large oil droplets into small oil droplets, and significantly reducing the interfacial energy between the oil and water phases.

[0024] Compared with the prior art, the present invention brings the following beneficial technical effects: (1) The present invention breaks through the bottleneck of existing oilfield corrosion inhibition and crude oil extraction technology by designing a composite nano-container structure of “hollow mesoporous silica-PEI layer-1,2-epoxy octadecane grafting”.

[0025] (2) Existing technologies are prone to ineffective consumption in non-corrosive areas, resulting in low corrosion inhibition efficiency and short duration. This invention solves this problem through the environmental responsiveness of the PEI layer: the corrosion area of ​​the oil pipeline forms an acidic environment due to metal oxidation reaction. The PEI layer of the nano-container is protonated and positively charged under acidic conditions, which can electrostatically adsorb with the negatively charged metal corrosion surface, thereby achieving precise enrichment of corrosion inhibitor in the corrosion area.

[0026] (3) In the prior art, the release of corrosion inhibitors is mostly an irreversible one-time release, which cannot dynamically adjust the release rate, resulting in "insufficient supply" when the initial corrosion is severe and "excessive supply" when the corrosion slows down in the later stage. The present invention relies on the synergistic effect of the mesoporous structure of hollow mesoporous silica and the PEI layer to construct a dynamic release system: in the early stage of acidification, the release rate is high, which quickly inhibits the corrosion reaction; as the corrosion slows down and the ambient pH increases, the release rate decreases, realizing the dynamic release of corrosion inhibitors.

[0027] (4) Existing technologies cannot simultaneously solve the core problems of pipeline corrosion and poor crude oil fluidity, requiring additional emulsifiers or corrosion inhibitors, which increases operating costs and complexity. This invention achieves functional integration through 1,2-epoxyoctadecane graft modification: the long carbon hydrophobic chain of 1,2-epoxyoctadecane forms a "hydrophilic-hydrophobic" binary structure with the hydrophilic amino group of the PEI layer, which can be adsorbed at the oil-water interface, turning large crude oil droplets into small droplets and forming a stable oil-in-water (O / W) emulsion. Attached Figure Description

[0028] Figure 1 This is a SEM image of HMSNs in Embodiment 1 of the present invention.

[0029] Figure 2 This is a SEM image of MBT@HMSNs@PEI grafted with octadecyl oxide in Example 1 of the present invention.

[0030] Figure 3 The FTIR spectra of HMSNs, MBT@HMSNs, and MBT@HMSNs@PEI in Embodiment 1 of the present invention are shown.

[0031] Figure 4 This is the N2 adsorption and desorption isotherm diagram of HMSNs in Example 1 of the present invention. Detailed Implementation

[0032] This invention proposes a nanocontainer with corrosion inhibitor release and emulsification capabilities, its preparation method, and its application. To make the advantages and technical solutions of this invention clearer and more explicit, the invention will be further described below with reference to specific embodiments.

[0033] MBT, mentioned in this invention, is an abbreviation for 2-mercaptobenzothiazole, and is used as a corrosion inhibitor.

[0034] The PEI mentioned in this invention is an abbreviation for polyethyleneimine.

[0035] The HMSNs mentioned in this invention are short for hollow mesoporous silica.

[0036] All the raw materials mentioned in this invention can be purchased through commercial channels.

[0037] The technical concept of this invention lies in addressing the technical problem that existing nanocontainers cannot simultaneously solve pipeline corrosion and poor crude oil flowability, and the release rate of corrosion inhibitors cannot be dynamically adjusted. To address this problem, this invention introduces hollow mesoporous silica as the outer shell of the nanocontainer, and sets a PEI layer on the outer surface of the shell. 1,2-Epoxyoctadecane is grafted onto the PEI layer. By designing a composite nanocontainer structure of "hollow mesoporous silica-PEI layer-1,2-epoxyoctadecane grafting," the bottleneck of existing oilfield corrosion inhibition and crude oil extraction technologies is overcome.

[0038] Example 1: A method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities, comprising the following steps: Step 1: Mix and completely dissolve 0.16 g of hexadecyltrimethylammonium bromide, 26 mL of anhydrous ethanol, and 55 mL of deionized water; add 1 mL of tetraethyl orthosilicate and stir for a period of time; then add 1 mL of ammonia water to the mixed solution containing tetraethyl orthosilicate and react at room temperature for a period of time to obtain a reaction solution; centrifuge, ultrasonically disperse, stir, and then dry the obtained reaction solution to obtain hollow mesoporous silica.

[0039] Step 2: 2-Mercaptobenzothiazole is loaded into a hollow mesoporous silica shell using a vacuum loading method to form MBT@HMSNs; the loading mass of 2-mercaptobenzothiazole in the hollow mesoporous silica is 30%.

[0040] Step 3: Prepare an acidic buffer solution with a pH of 3-4. The buffer solution is prepared by adding 2.55g of sodium acetate and 10mL of acetic acid to deionized water to obtain 120mL of buffer solution.

[0041] MBT@HMSNs were placed in a buffer solution, and sodium dodecylbenzenesulfonate was added and stirred. Then, polyethyleneimine with a molecular weight of 10,000 was added to the resulting mixture for reaction. The long molecular chain of polyethyleneimine (10,000) facilitates entanglement, resulting in a denser PEI layer after cross-linking, ensuring that the corrosion inhibitor MBT is not released prematurely. After a period of reaction, glutaraldehyde was added. The amino groups in polyethyleneimine and the aldehyde groups in glutaraldehyde form a Schiff base, causing the resulting PEI layer to coat the MBT@HMSNs, forming MBT@HMSNs@PEI. The mass ratio of MBT@HMSNs to sodium dodecylbenzenesulfonate was 1:1, and the mass ratio of MBT@HMSNs to polyethyleneimine was 1:0.3. The reaction time for adding polyethyleneimine was 3–5 hours.

[0042] Step 4: Add MBT@HMSNs@PEI to toluene for dissolution. The dissolution and stirring time is 2-4 hours, and the dissolution temperature is 70-80℃. The mass ratio of MBT@HMSNs@PEI to 1,2-epoxyoctadecane is 0.1:3. The grafting reaction time is 10-14 hours. After the grafting reaction is completed, dry in a drying oven.

[0043] The nanocontainers prepared in this embodiment are mixed with acidizing fluid and transported along with the acidizing fluid to oil well areas and pipeline corrosion-prone areas via a wellhead injection device. When the pipeline corrosion area faces a localized acidic environment, the outer PEI layer of the nanocontainer protonates under acidic conditions, carrying a positive charge. This positive charge is electrostatically adsorbed onto the negatively charged metal corrosion surface, achieving targeted delivery of the nanocontainers to the corrosion area. The acidic environment of the corrosion area disrupts the Schiff base bonds formed between glutaraldehyde and PEI, reducing the cross-linking density of the dense PEI layer and damaging the forces between HMSNs. The mesopores of the HMSNs swell slightly under acidic conditions, providing channels for the release of MBT corrosion inhibitors. In the initial stage of acidizing operations, the release rate is high, rapidly inhibiting the corrosion reaction; as corrosion slows and the ambient pH increases, the release rate decreases, achieving dynamic release of the corrosion inhibitor. The 1,2-epoxyoctadecane grafted onto the surface of the nanocontainer possesses hydrophobic long carbon chains that can insert into the interior of crude oil droplets, while the protonated PEI layer carries hydrophilic amino groups that are distributed on the outside of the droplets, forming a stable emulsion structure, namely an oil-in-water (O / W) emulsion. The viscosity of the emulsion is reduced, significantly improving the flowability of crude oil in pipelines, reducing transport resistance, and simultaneously increasing the separation efficiency of crude oil and produced fluid.

[0044] Example 2: The difference from Example 1 is that in step two, the loading mass of 2-mercaptobenzothiazole on hollow mesoporous silica is 25%.

[0045] Example 3: The difference from Example 1 is that in step two, the loading mass of 2-mercaptobenzothiazole on hollow mesoporous silica is 35%.

[0046] Comparative Example 1: The difference from Example 1 is that the molecular weight of polyethyleneimine is 1800.

[0047] Comparative Example 2: The difference from Example 1 is that 1,2-epoxyoctadecane is not grafted after MBT@HMSNs@PEI, that is, step four is not included.

[0048] A method for preparing a nanocontainer includes the following steps: Step 1: Mix and completely dissolve 0.16 g of hexadecyltrimethylammonium bromide, 26 mL of anhydrous ethanol, and 55 mL of deionized water; add 1 mL of tetraethyl orthosilicate and stir for a period of time; then add 1 mL of ammonia water to the mixed solution containing tetraethyl orthosilicate and react at room temperature for a period of time to obtain a reaction solution; centrifuge, ultrasonically disperse, stir, and then dry the obtained reaction solution to obtain hollow mesoporous silica.

[0049] Step 2: 2-Mercaptobenzothiazole is loaded into a hollow mesoporous silica shell using a vacuum loading method to form MBT@HMSNs; the loading mass of 2-mercaptobenzothiazole in the hollow mesoporous silica is 30%.

[0050] Step 3: Prepare an acidic buffer solution with a pH of 3-4. The buffer solution is prepared by adding 2.55g of sodium acetate and 10mL of acetic acid to deionized water to obtain 120mL of buffer solution.

[0051] MBT@HMSNs were placed in a buffer solution, and sodium dodecylbenzenesulfonate was added and stirred. Then, polyethyleneimine with a molecular weight of 10,000 was added to the resulting mixture for reaction. The long molecular chain of polyethyleneimine (10,000) facilitates entanglement, resulting in a denser PEI layer after cross-linking, ensuring that the corrosion inhibitor MBT is not released prematurely. After a period of reaction, glutaraldehyde was added. The amino groups in polyethyleneimine and the aldehyde groups in glutaraldehyde formed a Schiff base, causing the resulting PEI layer to coat the MBT@HMSNs, forming MBT@HMSNs@PEI. The mass ratio of MBT@HMSNs to sodium dodecylbenzenesulfonate was 1:1, and the mass ratio of MBT@HMSNs to polyethyleneimine was 1:0.3. The reaction time for adding polyethyleneimine was 3–5 hours.

[0052] Comparative Example 3: The difference from Example 1 is that: a polyethylene glycol emulsifier was grafted onto MBT@HMSNs@PEI.

[0053] A method for preparing a nanocontainer includes the following steps: Step 1: Mix and completely dissolve 0.16 g of hexadecyltrimethylammonium bromide, 26 mL of anhydrous ethanol, and 55 mL of deionized water; add 1 mL of tetraethyl orthosilicate and stir for a period of time; then add 1 mL of ammonia water to the mixed solution containing tetraethyl orthosilicate and react at room temperature for a period of time to obtain a reaction solution; centrifuge, ultrasonically disperse, stir, and then dry the obtained reaction solution to obtain hollow mesoporous silica.

[0054] Step 2: 2-Mercaptobenzothiazole is loaded into a hollow mesoporous silica shell using a vacuum loading method to form MBT@HMSNs; the loading mass of 2-mercaptobenzothiazole in the hollow mesoporous silica is 30%.

[0055] Step 3: Prepare an acidic buffer solution with a pH of 3-4. The buffer solution is prepared by adding 2.55g of sodium acetate and 10mL of acetic acid to deionized water to obtain 120mL of buffer solution.

[0056] MBT@HMSNs were placed in a buffer solution, and sodium dodecylbenzenesulfonate was added and stirred. Then, polyethyleneimine with a molecular weight of 10,000 was added to the resulting mixture for reaction. The long molecular chain of polyethyleneimine (10,000) facilitates entanglement, resulting in a denser PEI layer after cross-linking, ensuring that the corrosion inhibitor MBT is not released prematurely. After a period of reaction, glutaraldehyde was added. The amino groups in polyethyleneimine and the aldehyde groups in glutaraldehyde form a Schiff base, causing the resulting PEI layer to coat the MBT@HMSNs, forming MBT@HMSNs@PEI. The mass ratio of MBT@HMSNs to sodium dodecylbenzenesulfonate was 1:1, and the mass ratio of MBT@HMSNs to polyethyleneimine was 1:0.3. The reaction time for adding polyethyleneimine was 3–5 hours.

[0057] Step 4: Add MBT@HMSNs@PEI to toluene for dissolution. The dissolution and stirring time is 2-4 hours, and the dissolution temperature is 70-80℃. MBT@HMSNs@PEI reacts with polyethylene glycol emulsifier, and then is dried.

[0058] The nanocontainers prepared in Example 1 and Comparative Examples 1 to 3 were tested, and the test results are shown in Tables 1, 2, 3, 4, 5, and 6.

[0059] Table 1 Corrosion inhibition efficiency of the corrosion inhibitor in Example 1

[0060]

[0061] Table 2 shows the corrosion inhibition efficiency of the corrosion inhibitor in Comparative Example 1.

[0062]

[0063] Table 3 shows the corrosion inhibition efficiency of the corrosion inhibitors in Comparative Example 2.

[0064]

[0065] Table 4 Corrosion inhibition efficiency of the corrosion inhibitor in Comparative Example 3

[0066]

[0067] Table 5 Emulsification effect in Example 1

[0068]

[0069] Table 6 Emulsification effect in Comparative Example 1

[0070]

[0071] The nanocontainer prepared in Example 1 was subjected to simulated release, and the corrosion inhibition efficiency of the corrosion inhibitor at different times after release was obtained. This data was obtained from a weight loss experiment in 1M HCl. In Comparative Example 1, due to the small molecular weight of PEI, its cross-linking degree was reduced, leading to the release of the corrosion inhibitor during subsequent grafting, thus decreasing the corrosion inhibition efficiency. Comparative Examples 2 and 3 did not significantly affect the release or corrosion inhibition efficiency of the corrosion inhibitor, and therefore, the corrosion inhibition efficiency did not change significantly in the weight loss experiment. Emulsification experiments were conducted on the nanocontainer of Example 1 to obtain the emulsification index and oil separation rate. This data was obtained from emulsification experiments of the nanocontainer at different mass fractions. The experimental data showed that the emulsification effect improved with increasing concentration. In Comparative Example 1, due to the small molecular weight of PEI, its cross-linking degree was reduced, resulting in a smaller number of grafted 1,2-epoxyoctadecane molecules during subsequent grafting, thus decreasing the emulsification effect. In Comparative Examples 2 and 3, although PEI has a certain degree of hydrophobicity in its main chain, the entire molecule is surrounded by a large number of hydrophilic amine groups, making it strongly hydrophilic overall. It tends to dissolve in the aqueous phase rather than migrate to the oil-water interface. Polyethylene glycol is an extremely hydrophilic flexible chain, and PEI itself is also hydrophilic. This grafting structure further enhances the overall hydrophilicity of the molecule. The grafting of PEG further eliminates any slight hydrophobicity that PEI might possess, making the molecule even less willing to leave the aqueous phase and enter the oil-water interface. It dissolves completely in the aqueous phase, with almost no driving force for it to adsorb onto the interface.

[0072] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0073] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities, characterized in that: It includes the following steps: a. Using tetraethyl orthosilicate as raw material, HMSNs were prepared as shells by template method under the action of ammonia and hexadecyltrimethylammonium bromide. b. MBT is loaded into the shell of HMSNs using the vacuum loading method to form MBT@HMSNs; c. Prepare an acidic buffer solution, place MBT@HMSNs in the buffer solution, add sodium dodecylbenzenesulfonate and stir, then add PEI to the mixture and react. After reacting for a period of time, add glutaraldehyde. The amino group in PEI and the aldehyde group in glutaraldehyde form a Schiff base, so that the PEI layer forms a coating on the outside of MBT@HMSNs, forming MBT@HMSNs@PEI. d. Dissolve MBT@HMSNs@PEI and graft 1,2-epoxyoctadecane onto its PEI layer at a certain temperature to obtain a nanocontainer; the long carbon hydrophobic chain of 1,2-epoxyoctadecane forms a "hydrophilic-hydrophobic" binary structure with the hydrophilic amino group of the PEI layer, which can be adsorbed at the oil-water interface to form an oil-in-water emulsion.

2. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 1, characterized in that: The specific steps for preparing hollow mesoporous silica are as follows: 0.16 g of hexadecyltrimethylammonium bromide, 26 mL of anhydrous ethanol, and 55 mL of deionized water are mixed and completely dissolved; 1 mL of tetraethyl orthosilicate is added and stirred for a period of time; then 1 mL of ammonia water is added to the mixed solution containing tetraethyl orthosilicate, and the mixture is reacted at room temperature for a period of time to obtain a reaction solution; the obtained reaction solution is centrifuged, ultrasonically dispersed, stirred, and then dried to obtain hollow mesoporous silica.

3. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 2, characterized in that: In step b, the load quality of MBT in HMSNs is 25-35%.

4. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 2, characterized in that: In step c, the pH of the buffer solution is 3-4; the preparation steps of the buffer solution are as follows: add 2.55g of sodium acetate and 10mL of acetic acid to deionized water to obtain 120mL of buffer solution.

5. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 4, characterized in that: In step c, the mass ratio of MBT@HMSNs to sodium dodecylbenzenesulfonate is 1:1, and the mass ratio of MBT@HMSNs to PEI is 1:0.3; the reaction time after adding PEI is 3-5 h.

6. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 4, characterized in that: In step c, the mass-to-volume ratio of PEI to glutaraldehyde is 0.01:1 g / mL, and the reaction time after the addition of glutaraldehyde is 3–5 h.

7. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 1, characterized in that: In step d, MBT@HMSNs@PEI is added to toluene for dissolution. The dissolution and stirring time is 2-4 hours, and the dissolution temperature is 70-80℃. The mass ratio of MBT@HMSNs@PEI to 1,2-epoxyoctadecane is 0.1:

3. The grafting reaction time is 10-14 hours. After the grafting reaction is completed, the product is dried in a drying oven.

8. The method for preparing a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 1, characterized in that: The molecular weight of the PEI is 10,000.

9. A nanocontainer with corrosion inhibitor release and emulsification capabilities, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 8, and has an overall spherical structure. MBT is loaded inside the shell of hollow mesoporous silica. The mesopores distributed on the shell of hollow mesoporous silica enable the entry and exit of MBT and the loading. A PEI layer is wrapped around the outer layer of the hollow mesoporous silica, and 1,2-epoxyoctadecane with a hydrophobic long carbon chain structure is grafted onto the PEI layer.

10. The application of a nanocontainer with corrosion inhibitor release and emulsification capabilities according to claim 9, characterized in that: The application is as follows: Step 1: Mix the nano-container with the acidification solution and transport them together to the corrosion area; Step 2: When the corrosion zone faces a localized acidic environment, the PEI layer of the nanocontainer is protonated under acidic conditions, carrying a positive charge, and electrostatically adsorbs onto the negatively charged metal corrosion surface, thus achieving targeted delivery of the nanocontainer to the corrosion zone. The acidic environment of the corrosion zone is disrupted. Due to the Schiff base bond formed between glutaraldehyde and PEI, the cross-linking density of the dense PEI layer decreases, and the interaction forces between HMSNs are also disrupted. The mesopores of HMSNs swell under acidic conditions, providing a channel for the release of MBT corrosion inhibitor. Step 3: The 1,2-epoxyoctadecane grafted onto the surface of the nanocontainer has a hydrophobic long carbon chain that inserts into the interior of the crude oil droplet, while the PEI layer, after protonation, carries hydrophilic amino groups that are distributed on the outside of the droplet, forming a stable emulsion structure, namely an oil-in-water emulsion. The viscosity of the emulsion is reduced, improving the flowability of crude oil in the pipeline, and at the same time improving the separation efficiency of crude oil and produced fluid.

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