A mineral oil soil cleaning agent and a method for preparing the same

Abstract

This invention provides a mineral oil stain cleaner and its preparation method. The mineral oil stain cleaner comprises the following raw materials in the indicated mass percentages: 5%-20% choline chloride, 10%-30% alcohol hydrogen bond donor, 1%-8% composite surfactant, 5%-25% oily component, 3%-6% alkaline detergent, 0.3%-0.8% corrosion inhibitor, and 1%-2% chelating agent. The above components are less than 100%, with the balance being water. This invention has achieved outstanding technical progress in terms of cleaning performance, economy, environmental protection, and operability, and has extremely high industrial practical value and broad application prospects.

Description

Technical Field

[0001] This invention belongs to the technical field of industrial equipment cleaning, specifically relating to a mineral oil stain cleaning agent and its preparation method. Background Technology

[0002] Heat exchangers are core heat exchange equipment in industrial production. During long-term operation, mineral oils in the medium (such as lubricating oil, heat transfer oil, crude oil fractions, etc.) tend to adhere to and age on the heat exchange tube walls, forming a dense mixture of oil scale and sludge. This type of fouling will significantly reduce heat exchange efficiency, increase energy consumption, and in severe cases, block the flow channels and cause equipment failure.

[0003] Existing heat exchanger cleaning agents have many drawbacks: single alkaline cleaning agents are insufficient to dissolve heavy mineral oil scale, resulting in incomplete cleaning; strong acidic cleaning agents easily corrode heat exchanger substrates such as carbon steel and stainless steel, shortening the service life of the equipment; some solvent-containing cleaning agents are highly volatile, have poor environmental performance, and have unreasonable agent compatibility, which can easily lead to oil stain re-adhesion and secondary scaling after cleaning. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a mineral oil stain cleaner and its preparation method, thereby resolving the technical issues in the prior art.

[0005] In a first aspect, the present invention provides the following technical solution: a mineral oil stain cleaner, wherein the mineral oil stain cleaner comprises the following raw materials in the following mass percentages: 5%-20% choline chloride, 10%-30% alcohol hydrogen bond donor, 1%-8% compound surfactant, 5%-25% oily component, 3%-6% alkaline detergent builder, 0.3%-0.8% corrosion inhibitor, 1%-2% chelating agent. The above components are less than 100%, and the balance is water.

[0006] Compared with existing technologies, the advantages of this invention are as follows: First, the cleaning agent is highly versatile. By flexibly adjusting the compound ratio of oily components and surfactants, it can be applied to various waste mineral oil pollution scenarios, truly achieving "one agent for multiple uses"; Second, it has extremely high oil removal efficiency, reaching up to 98.5% when used in heat exchangers, and the solid surface after cleaning is completely transformed from oil-wetted to water-wetted; Third, it has extremely low corrosiveness. The compound corrosion inhibitor used in this invention has a corrosion rate for carbon steel and 304 stainless steel far lower than the national standard, meeting industry standard requirements and can be safely used in various metal equipment; Fourth, it has a significant cost advantage, requiring only raw materials such as choline chloride and methanol. White oil and other similar products are all bulk industrial chemicals with wide availability and stable prices; fifth, they are environmentally friendly and safe, as the cleaning agent does not contain strong acids, strong alkalis, or volatile toxic solvents, the cleaning waste is easy to treat, and the operation process has no irritating odor, ensuring the health of operators; finally, the preparation and cleaning processes are very simple, and all operations are completed under normal or low temperature, normal pressure, and low-speed stirring conditions, requiring no high-energy-consuming equipment, supporting offline and online cleaning, and easy to promote and implement in industrial workshops. In summary, this invention has achieved outstanding technical progress in terms of cleaning performance, economy, environmental protection, and operability, and has extremely high industrial practical value and broad application prospects.

[0007] Preferably, the alcohol hydrogen bond donor is one or more of methanol, ethanol, ethylene glycol, 1,2-propanediol, and glycerol.

[0008] Preferably, the composite surfactant is a compound of fatty alcohol polyoxyethylene ether, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether carboxylic acid, isotridecyl alcohol polyoxyethylene ether, and sodium fatty alcohol polyoxyethylene ether carboxylic acid, with a compound mass ratio of 12:42:12:18:16.

[0009] Preferably, the oily component is at least one of white oil, cyclohexane, or D-limonene.

[0010] Preferably, the alkaline detergent is anhydrous sodium carbonate.

[0011] Preferably, the corrosion inhibitor is a compound of benzotriazole and hexamethylenetetramine, with a mass ratio of 1:(1-2.5).

[0012] Preferably, the chelating agent is disodium ethylenediaminetetraacetate.

[0013] Secondly, the present invention provides the following technical solution: a method for preparing a mineral oil stain cleaner as described above, the method comprising: S1. Mix choline chloride, an alcohol hydrogen bond donor, and water according to the specified ratio, and then heat at room temperature at 400°C. Stir at 500 rpm for 20 seconds After 40 minutes, a uniform eutectic solvent was obtained; S2. While stirring, add the composite surfactant, oily component, alkaline detergent, corrosion inhibitor, chelating agent, and remaining water to the eutectic solvent, and continue stirring for 10 minutes. 20 min until completely dissolved or emulsified evenly; S3. Cool to room temperature to obtain the mineral oil stain cleaner. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 SEM images of the heat exchanger tube wall before and after cleaning, provided in an embodiment of the present invention; Figure 2 The different temperatures C provided in the embodiments of the present invention 18 Figure 1.00: Interfacial tension between E5Ac, TO-5 and their combined aqueous solution and cyclohexane; Figure 3 A single C provided for embodiments of the present invention 18 Cleaning status diagrams of the E5Ac system and its compound system after cleaning; Figure 4 Comparison chart of the oil dispersion effects of AEC-9Na, SDBS and compound emulsions provided in the embodiments of the present invention; Figure 5 A comparative diagram showing the emulsification and dispersion of oil stains and insoluble organic matter by AEC-9Na, SDBS, and compound emulsions provided in the embodiments of the present invention; Figure 6 The interfacial tension diagram of AEC-9Na, SDBS and their compound aqueous solution with cyclohexane provided in the embodiments of the present invention.

[0016] The embodiments of the present invention will be further described below with reference to the accompanying drawings. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain embodiments of the present invention, and should not be construed as limiting the present invention.

[0018] This invention provides a mineral oil stain cleaner, which comprises the following raw materials in weight percentages: 5%-20% choline chloride, 10%-30% alcohol hydrogen bond donor, 1%-8% compound surfactant, 5%-25% oily component, 3%-6% alkaline detergent builder, 0.3%-0.8% corrosion inhibitor, 1%-2% chelating agent. The above components are less than 100%, and the balance is water. The hydrogen bond donor of the alcohol is one or more of methanol, ethanol, ethylene glycol, 1,2-propanediol, and glycerol.

[0019] The composite surfactant is a compound of fatty alcohol polyoxyethylene ether, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether carboxylic acid, isotridecyl alcohol polyoxyethylene ether, and sodium fatty alcohol polyoxyethylene ether carboxylic acid, with a compound mass ratio of 12:42:12:18:16.

[0020] The oily component is at least one of white oil, cyclohexane, or D-limonene.

[0021] Specifically, the alkaline detergent builder is anhydrous sodium carbonate.

[0022] The corrosion inhibitor is a compound of benzotriazole and hexamethylenetetramine, with a mass ratio of 1:(1-2.5).

[0023] Specifically, the chelating agent is disodium ethylenediaminetetraacetate.

[0024] In other embodiments, the present invention also provides the following technical solution: a method for preparing a mineral oil stain cleaner, the method comprising: S1. Mix choline chloride, an alcohol hydrogen bond donor, and water according to the specified ratio, and then heat at room temperature at 400°C. Stir at 500 rpm for 20 seconds After 40 minutes, a uniform eutectic solvent was obtained; S2. While stirring, add the composite surfactant, oily component, alkaline detergent, corrosion inhibitor, chelating agent, and remaining water to the eutectic solvent, and continue stirring for 10 minutes. 20 min until completely dissolved or emulsified evenly; S3. Cool to room temperature to obtain the mineral oil stain cleaner.

[0025] The reagents and consumables used in this invention are all commercially available products. The invention will be further explained below with reference to relevant experiments: Example 1 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The formula consists of 12.5% ​​choline chloride, 20% alcohol hydrogen bond donor, 4% complex surfactant, 15% oily component, 4.5% alkaline detergent, 0.5% corrosion inhibitor, and 1.5% chelating agent. The above components are less than 100%, with the balance being water. The alcohol hydrogen bond donor is methanol. The complex surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% fatty alcohol polyoxyethylene ether carboxylic acid sodium. The oily component is white oil. The alkaline detergent is anhydrous sodium carbonate. The corrosion inhibitors are 0.25% benzotriazole and 0.25% hexamethylenetetraacetic acid. The chelating agent is disodium ethylenediaminetetraacetate.

[0026] Example 2 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 5% choline chloride, 20% methanol, 4% compound surfactant, 15% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0027] Example 3 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 20% choline chloride, 20% methanol, 4% compound surfactant, 15% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0028] Example 4 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition includes 12.5% ​​choline chloride, 10% methanol, 4% compound surfactant, 15% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0029] Example 5 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 12.5% ​​choline chloride, 30% methanol, 4% compound surfactant, 15% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0030] Example 6 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 12.5% ​​choline chloride, 20% methanol, 1% compound surfactant, 15% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.12% fatty alcohol polyoxyethylene ether, 0.42% sodium dodecylbenzenesulfonate, 0.12% fatty alcohol polyoxyethylene ether carboxylic acid, 0.18% isotridecyl alcohol polyoxyethylene ether, and 0.16% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0031] Example 7 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 12.5% ​​choline chloride, 20% methanol, 8% compound surfactant, 15% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.96% fatty alcohol polyoxyethylene ether, 3.36% sodium dodecylbenzenesulfonate, 0.96% fatty alcohol polyoxyethylene ether carboxylic acid, 1.44% isotridecyl alcohol polyoxyethylene ether, and 1.28% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0032] Example 8 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 12.5% ​​choline chloride, 20% methanol, 4% compound surfactant, 5% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0033] Example 9 A mineral oil stain cleaner, the mineral oil stain cleaner comprising the following raw materials in weight percentages: The composition consists of 12.5% ​​choline chloride, 20% methanol, 4% compound surfactant, 25% white oil, 4.5% anhydrous sodium carbonate, 0.5% corrosion inhibitor, and 1.5% disodium ethylenediaminetetraacetate. The above components are less than 100%, with the remainder being water. The compound surfactant includes 0.48% fatty alcohol polyoxyethylene ether, 1.68% sodium dodecylbenzenesulfonate, 0.48% fatty alcohol polyoxyethylene ether carboxylic acid, 0.72% isotridecyl alcohol polyoxyethylene ether, and 0.64% sodium fatty alcohol polyoxyethylene ether carboxylic acid. The corrosion inhibitor consists of 0.25% benzotriazole and 0.25% hexamethylenetetramine.

[0034] Compare with Example 1 The mineral oil stain cleaner provided in this comparative example does not contain choline chloride or alcohol hydrogen bond donors.

[0035] Compare with Example 2 The mineral oil stain cleaner provided in this comparative example does not contain compound surfactants.

[0036] Compare with Example 3 This comparative example provides a mineral oil stain cleaner that does not contain oily components.

[0037] Low eutectic experiment In this application, alcohols and water serve as hydrogen bond donors, and choline chloride acts as a hydrogen bond acceptor. A mixture of choline chloride, water, and methanol forms a low-eutectic component. In the microemulsion, the microemulsion phase, with its low surface tension, acts on the base oil adsorbed on the heat exchanger tube wall, reducing the surface tension of the base oil and weakening its adsorption on the tube wall. The remaining phase in the microemulsion consists of white oil. According to the principle of "like dissolves like," the base oil desorbed from the heat exchanger tube wall easily dissolves into the white oil. Simultaneously, the microemulsion phase readily adheres to the heat exchanger tube wall, occupying adsorption sites for the base oil and preventing its re-adsorption onto the tube wall surface, thus further improving the cleaning effect of the microemulsion. The low-eutectic component in this application can replace the microemulsion phase because the formulated low-eutectic component has properties similar to the microemulsion. When the mineral oil descaling agent provided in Example 1 is used to clean the heat exchanger tube wall, the low-surface-tension eutectic component reduces the surface tension of the base oil, weakens the adsorption of the base oil on the heat exchanger tube wall, and makes it easier to peel the base oil off the heat exchanger tube wall. The white oil dissolves the desorbed base oil. At the same time, since the heat exchanger tube wall is hydrophilic, the eutectic solvent will adhere to the heat exchanger tube wall and occupy the adsorption sites on the heat exchanger tube wall, preventing the base oil from being re-adsorbed on the heat exchanger tube wall, further improving the cleaning effect of the cleaning agent.

[0038] The heat exchanger tube walls were cleaned using the mineral oil descaling agent provided in Example 1. SEM analysis was performed on the heat exchanger tube walls before and after cleaning to observe their microstructure. The results are as follows: Figure 1 As shown; Figure 1 Images (a) and (b) in the figure show the morphology of the heat exchanger tube wall before cleaning. Figure 1 Images (c) and (d) show the morphology of the heat exchanger tube wall after cleaning, with the solid particles representing attached, fixed impurities. Figure 1 As can be seen, the size of the impurities after cleaning is much smaller than that before cleaning. When the heat exchanger tube wall is adsorbed with base oil, the impurities are easy to aggregate. Therefore, large particles were found before cleaning, but the size of the impurities after cleaning is smaller and they are not easy to aggregate.

[0039] Meanwhile, EDS analysis was performed on its surface to investigate the changes in the content of various elements in the heat exchanger tube wall before and after cleaning. The results are shown in Table 1. Table 1

[0040] As shown in Table 1, the carbon content of the heat exchanger tube wall decreased significantly after cleaning, from 36.99 wt% to 5.74 wt%, indicating that a large amount of adsorbed oil on the heat exchanger tube wall was removed and the cleaning effect was good.

[0041] Cleaning mechanism of composite surfactants 1. Fatty alcohol polyoxyethylene ether (AEO-9), sodium dodecylbenzenesulfonate (SDBS) Fatty alcohol polyoxyethylene ethers can significantly reduce the surface tension of cleaning agents (reducing the surface tension of water from 72 mN / m to below 30 mN / m), allowing the cleaning agent to quickly penetrate into the tiny gaps between oil stains and solid surfaces, weakening the adhesion of oil stains. Fatty alcohol polyoxyethylene ether molecules are adsorbed at the oil / water interface, with hydrophobic groups inserted into the oil phase and hydrophilic groups extending into the water phase, forming an O / W emulsion. The oil stains are dispersed into tiny oil droplets (0.1-10 μm in diameter), stably suspended in the cleaning agent, preventing the oil stains from re-aggregating. Fatty alcohol polyoxyethylene ethers are adsorbed on the surface of solid particles, preventing the particles from re-aggregating through steric hindrance (spatial extension of polyoxyethylene chains), keeping the solid phase dispersed after cleaning.

[0042] Sodium dodecylbenzenesulfonate is an anionic surfactant with extremely rapid adsorption at the oil / water interface (fast kinetics). It can reduce the interfacial tension of the oil / water interface from approximately 50 mN / m to 8-10 mN / m within seconds, making it easier for oil stains to peel off from solid surfaces. When the concentration of sodium dodecylbenzenesulfonate exceeds the critical micelle concentration, micelles are formed. The micelles can solubilize nonpolar mineral oil molecules, "encapsulating" the oil stains within the micelle core, achieving dissolution and cleaning. After adsorbing onto the surface of oil droplets or solid particles, sodium dodecylbenzenesulfonate imparts a negative charge. Electrostatic repulsion is generated between the particles, preventing oil droplet coalescing or solid particles re-aggregating, thus improving the stability of the cleaning agent.

[0043] Fatty alcohol polyoxyethylene ether (FAE) inserts into the micelles formed by sodium dodecylbenzenesulfonate (DOS), shielding the electrostatic repulsion between the head groups of DOS and facilitating micelle formation. FAE and DOS form a mixed adsorption layer at the oil / water interface, resulting in a more compact molecular arrangement and higher interfacial film strength. FAE provides steric hindrance (the spatial extension of the polyoxyethylene chains), further enhancing oil droplet stability, while DOS provides electrostatic repulsion, preventing droplet coalescence. DOS is sensitive to calcium and magnesium ions, easily forming insoluble calcium / magnesium salt precipitates (calcium soaps), affecting cleaning performance. The polyoxyethylene chains of FAE can chelate calcium and magnesium ions, protecting DOS. FAE has stronger hydrophilicity and low surface tension, allowing for rapid spreading on solid surfaces, while DOS enhances the binding of water molecules to the solid surface through charge adsorption.

[0044] 2. Fatty alcohol polyoxyethylene ether carboxylic acid C 18 E5Ac, Isotridecyl polyoxyethylene ether TO-5 First, we analyze the process by which the cleaning agent strips and emulsifies oil from the heat exchanger tube walls. This process involves the adsorption behavior of surfactants at the oil-water interface. Interfacial tension can be used to analyze the adsorption of surfactants at the oil-water interface by measuring C at different temperatures. 18 The interfacial tensions between E5Ac, TO-5, and their combined aqueous solutions with cyclohexane are shown in the following figures. Figure 2 , Figure 2 (a) in the figure is the dynamic interfacial tension curve at 5℃. Figure 2 (b) shows the interfacial tension values ​​at different temperatures over 3600 s. At the cleaning temperature, the equilibrium interfacial tension of TO-5 is approximately 8 mN / m. 18 The equilibrium interfacial tensions of both E5Ac and the compound system are around 6 mN / m, with little difference between them. The interfacial tension of the compound system is slightly lower than that of C. 18 E5Ac. With increasing temperature, the interfacial tension of the TO-5 system first decreases and then increases. When the temperature rises from 5℃ to 50℃, the interfacial tension decreases from 7.7 mN / m to 6.7 mN / m. This is because appropriate heating can enhance molecular thermal motion, leading to a decrease in the interfacial tension. When the temperature rises from 50℃ to 70℃, the interfacial tension increases from 6.7 to 8.4 mN / m. The hydrophilicity of TO-5 containing EO units decreases with increasing temperature, resulting in a decrease in emulsifying properties; C 18 The interfacial tension of E5Ac and the compound system increases with increasing temperature, where C 18 The interfacial tension of the E5Ac system increased from 5.6 to 7.9 mN / m, and that of the compound system increased from 5.9 to 8.2 mN / m. This is because C 18 The carboxyl groups in E5Ac exhibit increased ionization with rising temperature, leading to decreased adsorption at the oil-water interface. Interfacial tension results indicate that the performance of the compound system is less affected by temperature, with even lower interfacial tension at lower temperatures. The system's ability to reduce oil-water interfacial tension primarily depends on C. 18 E5Ac, along with the compound system, under synergistic effect, increases the amount of surfactant adsorbed on the oil-water interface film, enhances interfacial activity, and improves emulsification and cleaning effect.

[0045] Simultaneously, the stable dispersion process of oil stains on the heat exchanger tube walls in the cleaning agent was analyzed. 18 The carboxylic acid groups in E5Ac can react with alkaline substances in oil stains to break down the oil stain structure. Simultaneously, it has a strong ability to reduce the interfacial tension between oil and water. 18 E5Ac can effectively remove oil stains from the heat exchanger tube walls, but after cleaning, some oil residue remains on the tube walls. Figure 3 As shown, Figure 3(a) in the text represents a single C. 18 State diagram of the cleaning agent after cleaning with the E5Ac system. Figure 3 (b) in the text represents a single C. 18 Microscopic image of the precipitated oil phase after cleaning with the E5Ac system. Figure 3 (c) in the diagram shows the state of the cleaning agent after cleaning the compound system. Figure 3 Image (d) shows a microscopic image of the upper emulsion of the compound system after cleaning. After cleaning, some of the oil phase in the cleaning agent has demulsified and floats above the aqueous phase. Large areas of oil phase or water-in-oil emulsion are clearly observed in the optical microscope image. A single C... 18 E5Ac cannot stably disperse oil stains. When TO-5 is added to the system, there is no obvious residue on the heat exchanger tube wall after cleaning. The oil stains are stably dispersed in the cleaning agent, proving that the compound system with TO-5 can stably disperse oil stains. The detached oil stains will not re-adhere to the heat exchanger tube wall during the cleaning process, which is beneficial to the cleaning of the heat exchanger tube wall.

[0046] Therefore, after the cleaning agent comes into contact with the oil stains, the cleaning agent reduces the viscosity of the oil stains to a certain extent. 18 E5Ac effectively reduces the interfacial tension between oil and water. Under the emulsifying and dispersing effect of the cleaning agent, oil is peeled off from the well wall and dissolved in the emulsion droplets. At the same time, the stability of the emulsion is maintained by TO-5, ultimately achieving the cleaning of the heat exchanger tube wall of the well.

[0047] 3. Sodium fatty alcohol polyoxyethylene ether carboxylate (AEC-9Na), sodium dodecylbenzenesulfonate (SDBS) To investigate the effects of two surfactants in oil stain cleaning, 10 wt% cyclohexane emulsions were prepared using the same concentrations of AEC-9Na, SDBS, and a mixture of AEC-9Na and SDBS. These emulsions were mixed with oil stains on the heat exchanger tube walls at a solid-liquid ratio of 1:4. The stirring speed was fixed at 500 r / min, and the cleaning time was 30 min. After stirring, the state changes of the mixture were observed. Figure 4 As shown.

[0048] The mixture of AEC-9Na emulsion and oil showed significant particle sedimentation immediately after stirring, and the upper liquid phase contained few emulsion droplets from the oil phase of the emulsified oil, indicating poor dispersion and cleaning effects on oil particles. This is because commercial AEC-9Na is a mixture containing a certain amount of carboxylic acid groups (-COOH), which cause oil particles to agglomerate under electrostatic effects. The mixture of SDBS emulsion and oil did not show significant particle sedimentation immediately after stirring, and the dispersion of oil particles remained good after 30 minutes of standing, indicating that the SDBS emulsion has a good ability to disperse oil-containing particles in oil. However, after 2 hours of standing, adhesion to the container walls at higher positions was observed in the SDBS emulsion mixture, indicating that the particles suspended in the cleaning agent during stirring were still oil-wetted, proving that the cleaning agent has a poor cleaning effect on the bound oil on the particle surface. The mixture of emulsion and oil formed by AEC-9Na and SDBS did not show obvious particle sedimentation immediately after stirring and standing for 30 minutes. After standing for 2 hours, the lighter-colored particles gradually settled to the bottom, and the wall surface was relatively clean. The mixed emulsion system had good ability to disperse particles and emulsify the oil phase.

[0049] To further investigate the effects of the two surfactants, oil stains and insoluble organic matter were mixed with emulsions formed by AEC-9Na, SDBS, and a mixture of AEC-9Na and SDBS at a mass ratio of 1:9, respectively. After stirring, the changes in the state of the mixture were observed. Figure 5 As shown.

[0050] Observing the phenomena of oil dispersion experiments, the AEC-9Na mixture showed rapid droplet rise, and the emulsion did not break down after 2 hours of standing, indicating that the oil droplets in the mixture were relatively large and the emulsion effect was poor, but the emulsion stability was strong. The SDBS mixture showed slower droplet rise, and the emulsion droplets were smaller, but after 2 hours of standing, the darker-colored contaminating oil floated to the surface of the emulsion, indicating that although SDBS had a good emulsification effect on oil, the emulsion stability was poor. The AEC-9Na and SDBS compound mixture showed slow droplet rise, and the oil did not float to the surface of the emulsion after 2 hours of standing, indicating that the two were a compound mixture. Afterwards, the emulsion showed good emulsification and dispersion of oil stains, and the emulsion was relatively stable. Observation of the dispersion of insoluble organic matter showed that the droplets in the AEC-9Na mixture rose slowly, and the container walls were relatively clean, proving that AEC-9Na has a strong ability to emulsify and disperse insoluble organic matter. After stirring, the droplets in the SDBS mixture rose rapidly, and the container walls were sticky, proving that SDBS has a poor effect on emulsifying and dispersing insoluble organic matter. The AEC-9Na and SDBS compound mixture was relatively uniform overall, proving that the emulsion prepared by the two compound mixture can effectively emulsify and disperse insoluble organic matter.

[0051] The above experiments show that AEC-9Na can peel off insoluble organic matter and other difficult-to-clean parts from the particle surface; SDBS can emulsify oil stains well and disperse oil-containing particles well, but its ability to emulsify and disperse insoluble organic matter is poor. Therefore, the cleaning agents prepared by SDBS or AEC-9Na alone have low oil removal efficiency.

[0052] The interfacial tension between AEC-9Na, SDBS, and their combined aqueous solutions with cyclohexane was measured. Figure 6 As shown, the equilibrium interfacial tension of SDBS at room temperature is approximately 8 mN / m. Both AEC-9Na and the compound system achieve an equilibrium interfacial tension of 6 mN / m, with little difference between them. The equilibrium interfacial tension of the compound system is lower than that of SDBS. From a kinetic perspective, the addition of SDBS to the system rapidly reduces the interfacial tension between oil and water, bringing it to a stable value. The interfacial tension results indicate that the ability of the compound system to reduce the interfacial tension between oil and water mainly depends on AEC-9Na, consistent with the experimental phenomena observed in the emulsion dispersion of insoluble organic matter.

[0053] In summary, after the cleaning agent comes into contact with the oil stains, it disperses the oil-containing particles in the oil stains, increases the contact area between the cleaning agent and the particles, and peels off the oil phase and insoluble organic matter on the surface of the oil stain particles during the stirring process. The oil is then emulsified into the cleaning agent. After the oil phase is removed, the oil stain particles settle to the bottom of the container under the action of gravity, and the oil stains and particles are separated, thus achieving the cleaning standard.

[0054] Steel sheet corrosion test The cleaning agent from Example 1 was used to clean N80 steel sheets at different temperatures. The corrosion effect of the cleaning agent on the N80 steel sheets at different temperatures was observed using the static hanging plate method. The corrosion rate was calculated by differential weighing, including the weight of the steel sheet before corrosion, the weight after corrosion, the weight loss due to corrosion, and the corrosion rate. The corrosion rates of the cleaning agent on the N80 steel sheets at 5, 25, and 60°C were 0.0625, 0.1042, and 0.1250 g / (m³), respectively. 2 The corrosion rate increases with increasing temperature (·h), and the current industry standard requires that the corrosion rate of steel sheets at 60℃ should not exceed 5g / (m). 2 The corrosion rate of the cleaning agent on N80 steel sheets is much lower than that of the standard, proving that the corrosion rate of the cleaning agent on the heat exchanger tube wall meets national requirements.

[0055] Cleaning effect experiment Several heat exchangers were selected, and the differences in weight and oil content of the oil adhering to the tube walls were controlled within a preset range. The cleaning agents of the above embodiments and comparative examples were used to circulate and clean the corresponding heat exchangers at 60°C for 3 hours. Then, the oil content of each group was determined, and the oil removal rate was determined (n=3, error ±0.3 wt%). The results are shown in Figure 2. Table 2

[0056] As can be seen from Examples 1 to 3, insufficient choline chloride results in a lack of hydrogen bond acceptors, a low amount of eutectic solvent generated, and a reduced ability to decrease surface tension and weaken oil adsorption. At the same time, the effect of occupying adsorption sites on the pipe wall becomes worse. Excessive choline chloride disrupts the optimal molar ratio of the eutectic solvent, leading to excessively high system viscosity or phase separation, which affects the formation and permeability of microemulsions. As can be seen from Examples 1, 4, and 5, insufficient methanol results in a lack of hydrogen bond donors, making it impossible to fully form a eutectic solvent with choline chloride, thus limiting the effect of reducing surface tension. Excessive methanol dilutes the system, alters polarity, and affects the adsorption of surfactants at the oil-water interface, while potentially causing the properties of the eutectic solvent to deviate from the optimal range.

[0057] As can be seen from Examples 1, 6, and 7, the composite surfactant is severely insufficient, far below the CMC, and cannot form enough micelles. The oil-water interfacial tension is not sufficiently reduced, and the oil is difficult to disperse into tiny oil droplets. When the composite surfactant is excessive, multilayer adsorption or excessive aggregation of micelles occurs, the viscosity of the system increases, the permeability decreases, and a liquid crystal phase may be formed to hinder the removal of oil.

[0058] As can be seen from Examples 1, 8, and 9, if there is too little white oil, according to the principle of "like dissolves like," the ability to dissolve and desorb the base oil is insufficient, and it cannot effectively accommodate the stripped oil, which easily leads to the re-adsorption of oil. If there is too much white oil, it may cause the O / W type microemulsion to transform into a W / O type or a bicontinuous phase, changing the hydrophilic-lipophilic balance (HLB) of the cleaning agent. At this time, the affinity of the cleaning agent for the water-wetted metal pipe wall decreases, and the oil removal efficiency decreases.

[0059] Based on comparative examples one to three, it can be seen that the lack of a low eutectic solvent core component makes it impossible to form a low surface tension microemulsion phase, resulting in extremely poor ability to reduce the surface tension of oil stains and weaken adsorption, and it is unable to occupy the adsorption sites on the pipe wall to prevent back adhesion; the lack of a composite surfactant completely eliminates the emulsifying ability, making it impossible to reduce the oil-water interfacial tension, and the oil stains cannot be peeled off and dispersed into a stable emulsion, so the effect of alkaline detergent alone is extremely limited; the lack of a similar-mixed dissolving carrier means that the peeled oil stains cannot be effectively dissolved and contained, and back adhesion or re-aggregation is likely to occur.

[0060] Therefore, it can be seen that the mineral oil stain cleaner in this application has several advantages. First, it is highly versatile; by flexibly adjusting the ratio of oily components and surfactants, it can be applied to various waste mineral oil pollution scenarios, truly achieving "one agent for multiple uses." Second, it has extremely high oil removal efficiency, reaching up to 98.5% when used in heat exchangers, and the solid surface is completely transformed from oil-wetted to water-wetted after cleaning. Third, it has extremely low corrosiveness; the compound corrosion inhibitor used in this invention has a corrosion rate for carbon steel and 304 stainless steel far lower than the national standard, meeting industry standard requirements and can be safely used in various metal equipment. Fourth, it has a significant cost advantage, and the raw materials include choline chloride and methyl chloride. Alcohols and white oils are both bulk industrial chemicals, widely available and with stable prices; fifth, they are environmentally friendly and safe, the cleaning agent does not contain strong acids, strong alkalis or volatile toxic solvents, the cleaning waste is easy to treat, and the operation process has no irritating odor, ensuring the health of operators; finally, the preparation and cleaning processes are very simple, all operations are completed under normal or low temperature, normal pressure and low speed stirring conditions, no high energy consumption equipment is required, offline and online cleaning are supported, and it is easy to promote and implement in industrial workshops. In summary, this invention has achieved outstanding technical progress in terms of cleaning performance, economy, environmental protection and operability, and has extremely high industrial practical value and broad application prospects.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A mineral oil soil cleaning agent, characterized by, The mineral oil stain cleaner comprises the following raw materials in weight percentages: 5%-20% choline chloride, 10%-30% alcohol hydrogen bond donor, 1%-8% compound surfactant, 5%-25% oily component, 3%-6% alkaline detergent builder, 0.3%-0.8% corrosion inhibitor, 1%-2% chelating agent. The above components are less than 100%, and the balance is water.

2. The mineral oil soil cleaner of claim 1, wherein, The alcohol hydrogen bond donor is one or more of methanol, ethanol, ethylene glycol, 1,2-propanediol, and glycerol.

3. The mineral oil soil cleaner of claim 1, wherein, The composite surfactant is a compound of fatty alcohol polyoxyethylene ether, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether carboxylic acid, isotridecyl alcohol polyoxyethylene ether, and sodium fatty alcohol polyoxyethylene ether carboxylic acid, with a compound mass ratio of 12:42:12:18:

16.

4. The mineral oil soil cleaner of claim 1, wherein, The oily component is at least one of white oil, cyclohexane, or D-limonene.

5. The mineral oil soil cleaner of claim 1, wherein, The alkaline detergent builder is specifically anhydrous sodium carbonate.

6. The mineral oil soil cleaner of claim 1, wherein, The corrosion inhibitor is a compound of benzotriazole and hexamethylenetetramine, with a mass ratio of 1:(1-2.5).

7. The mineral oil soil cleaner of claim 1, wherein, The chelating agent is specifically disodium ethylenediaminetetraacetate.

8. A process for preparing the mineral oil soil cleaning agent according to claim 1, characterized by, The method includes: S1, choline chloride, alcohol hydrogen bond donor and water were mixed according to the ratio, stirred at 400 rpm at room temperature for 20 40 min, and a uniform eutectic solvent was obtained. 40 min, and a uniform eutectic solvent was obtained. S2. To the eutectic solvent, with stirring, add the complex surfactant, the oily component, the alkaline builder, the corrosion inhibitor, the chelating agent, and the remaining water, and continue stirring for 10 20 min to complete dissolution or emulsification. S3. Cool to room temperature to obtain the mineral oil stain cleaner.

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