Environment-friendly total-synthesis concentrated solution for hydraulic support and preparation method of concentrated solution

Abstract

The invention belongs to the technical field of coal mine machinery lubrication and hydraulic transmission, and discloses an environment-friendly total-synthesis concentrated solution for a hydraulic support and a preparation method of the concentrated solution. The biological sensing microcapsule corrosion inhibitor is characterized by comprising 0.5%-3.0% of a biological sensing microcapsule, 8.0%-15.0% of a main corrosion inhibitor, 2.0%-6.0% of an auxiliary corrosion inhibitor, 4.0%-10.0% of a water-soluble lubricant, 0.05%-0.2% of an anti-foaming agent, 1.0%-3.0% of a pH buffering agent and deionized water. Wherein the biological sensing microcapsule has a core-shell-shell structure, is integrated with electroactive microorganisms, an electron mediator carrier and a corrosion inhibition precursor release layer, and can trigger targeted release of benzotriazole derivatives when the pH value of a local corrosion microarea is less than or equal to 5.5. The corrosion inhibitor has excellent corrosion protection performance and environment-friendly characteristics, effectively overcomes the problem of inactivation of microorganisms under severe hydraulic working conditions through a microcapsule encapsulation strategy, realizes accurate matching of corrosion signal in-situ sensing and corrosion inhibition response, remarkably improves the anti-rust performance under high-shear and wide-temperature-range working conditions, and has wide application prospects. And meanwhile, the requirements of environmental protection and sealing material compatibility are met.

Description

An environmentally friendly fully synthetic hydraulic support concentrate and its preparation method Technical Field

[0001] This invention belongs to the field of coal mine machinery lubrication and hydraulic transmission technology, and relates to an environmentally friendly fully synthetic hydraulic support concentrate and its preparation method. Background Technology

[0002] Hydraulic supports, as the core equipment of the support system for fully mechanized coal mining faces, rely heavily on the performance stability of the hydraulic transmission medium for their operational reliability. In high-water-based hydraulic fluid systems, the concentrate, as a key component, not only provides basic lubrication and sealing functions but also plays a crucial role in inhibiting corrosion of metal components and ensuring the long-term safe operation of the system.

[0003] In existing technologies, concentrated fluids for fully synthetic hydraulic supports often use organic carboxylates, phosphate esters, or silane compounds as the main corrosion inhibitors, forming a dense passivation film on the metal surface to block corrosive media. This approach performs well in macroscopic, uniform corrosion protection, and some components possess certain biodegradability potential. However, in areas without corrosion risk, it leads to ineffective consumption of the corrosion inhibitor, reducing the system's economy and long-term effectiveness. Furthermore, when facing micro-areas with enhanced localized electrochemical activity, such as pitting and crevice corrosion, traditional corrosion inhibitors lack the ability to detect corrosion initiation points, failing to provide on-demand, targeted, and enhanced corrosion inhibition. This causes micro-corrosion pits to rapidly expand into structural damage, seriously threatening the sealing integrity of the hydraulic system and the operational accuracy of the support.

[0004] Some electroactive microorganisms (such as Shewanella and Geobacter) possess transmembrane electron transport capabilities and can form a bioelectrochemical sensing layer at the metal-solution interface. Their metabolic activity is highly sensitive to changes in the local corrosion microenvironment and can indirectly affect metal corrosion kinetics by regulating extracellular electron flow or secreting specific metabolites. Integrating such microorganisms or their functional components into hydraulic fluid systems can theoretically construct a sensing-response integrated bio-corrosion inhibition mechanism. Summary of the Invention

[0005] To achieve the above-mentioned objectives, this invention provides an environmentally friendly, fully synthetic hydraulic support concentrate and its preparation method. Based on a microbial electrochemical sensing and response mechanism, the concentrate constructs an intelligent anti-rust system capable of in-situ identifying localized corrosion micro-regions and triggering targeted corrosion inhibition responses. While ensuring environmental friendliness, it significantly enhances the ability to suppress localized corrosion forms such as pitting and crevice corrosion, and maintains the long-term operational stability of the hydraulic system under high shear, wide temperature range, and complex working conditions.

[0006] The environmentally friendly fully synthetic hydraulic support concentrate of this invention is composed of the following components by mass percentage: 0.5%-3.0% biosensing microcapsules, 8.0%-15.0% primary corrosion inhibitor, 2.0%-6.0% auxiliary corrosion inhibitor, 4.0%-10.0% water-soluble lubricant, 0.05%-0.2% antifoaming agent, 1.0%-3.0% pH buffer, and the balance being deionized water; wherein, the biosensing microcapsules contain immobilized electroactive microbial cells, an electron mediator carrier, and a corrosion inhibitor precursor release layer, the three of which are integrated in a core-shell-shell three-layer structure within a single microcapsule unit.

[0007] The immobilized electroactive microbial cells are selected from at least one of Shewanella MR-1 or Geobacter PCA, with a cell density of 1 × 10⁻⁶ cells per milliliter. 8 Up to 5×10 9 Live bacteria are encapsulated in a sodium alginate-chitosan bilayer to form spherical gel particles with a diameter of 2-10 μm; the electron mediator carrier is a mesoporous silica nanoparticle loaded with 2,2'-bipyridine-5,5'-dicarboxylic acid iron complex, with an average particle size of 50-150 nm, a pore size of 3-8 nm, and a loading of 15%-25% (by mass); the corrosion inhibitor precursor release layer is made by blending polylactic acid-glycolic acid copolymer (PLGA) and benzotriazole derivative at a mass ratio of 7:3, with a thickness of 200-500 nm, and is coated on the outer surface of the electron mediator carrier.

[0008] In a preferred embodiment of the present invention, the main corrosion inhibitor is a compound of disodium sebate and potassium dodecyl phosphate, with a mass ratio of 3:2; the disodium sebate has a molecular weight of 262.22 and a water solubility greater than 50 g / L (25°C); the potassium dodecyl phosphate has an alkyl chain length of C12, a phosphate content greater than 95.0%, and a critical micelle concentration of 0.8 mmol / L.

[0009] In another preferred embodiment of the present invention, the auxiliary corrosion inhibitor is a mixture of sodium phytate and sodium molybdate in a mass ratio of 4:1; the sodium phytate has a phytic acid content greater than 85.0% and a pH value of 6.5-7.5 (1% aqueous solution); the sodium molybdate is a dihydrate with a molybdenum content greater than 39.0%.

[0010] The water-soluble lubricant is a composite of polyethylene glycol monolaurate and glycerol polyoxyethylene ether in a mass ratio of 1:1; the polyethylene glycol monolaurate has a degree of polymerization of 20 and a hydroxyl value of 56 mgKOH / g; the glycerol polyoxyethylene ether has an ethylene oxide addition number of 15 and an HLB value of 13.5.

[0011] The antifoaming agent is a polydimethylsiloxane emulsion with a solid content of 10%, an average particle size of 1-3 μm, and a viscosity of 1000 mPa·s (25℃).

[0012] The pH buffer is a buffer pair of tris(hydroxymethyl)aminomethane and sodium citrate in a molar ratio of 1:1, which together maintains the pH value of the concentrated solution system within the range of 8.2-8.8.

[0013] The preparation method of the concentrated solution for the environmentally friendly fully synthetic hydraulic support of the present invention includes the following steps: Step 1, preparation of biosensing microcapsules: The electroactive microbial cell suspension and 2% sodium alginate solution are mixed at a volume ratio of 1:4, and then dropped into 0.1 mol / L calcium chloride solution to solidify and form calcium alginate microspheres; the microspheres are then immersed in 0.5% chitosan acetate solution (pH=5.2) for cross-linking for 10 minutes, and after washing, immobilized cell microparticles are obtained; the mesoporous silica nanoparticles are dispersed in an ethanol solution containing 0.1 mol / L 2,2'-bipyridine-5,5'-dicarboxylic acid iron complex, stirred and adsorbed for 2 hours, and centrifuged and dried to obtain an electron mediator carrier; the electron mediator carrier and immobilized cell microparticles are uniformly mixed at a mass ratio of 3:1, suspended in a dichloromethane solution containing 5% PLGA and 2% benzotriazole derivative, and a double-shell microcapsule is formed by emulsification-solvent evaporation method, and then freeze-dried to obtain the finished biosensing microcapsule.

[0014] Step 2, prepare the basic liquid phase: heat deionized water to 40°C, add pH buffer, auxiliary corrosion inhibitor and water-soluble lubricant in sequence, stir until completely dissolved to form a transparent homogeneous solution A.

[0015] Step 3, add the main corrosion inhibitor: After preheating the main corrosion inhibitor to 50°C, slowly add it to solution A and stir at 300 rpm for 30 minutes to obtain solution B.

[0016] Step 4, Introduce functional microcapsules: Disperse the biosensing microcapsules in a small amount of deionized water, sonicate for 5 minutes to form a uniform suspension, slowly add to solution B, and continue stirring for 20 minutes.

[0017] Step 5, add antifoaming agent: Add antifoaming agent to the above mixture, stir at 500 rpm for 15 minutes at 60°C, cool to room temperature, filter to remove impurities, and obtain the environmentally friendly fully synthetic hydraulic support concentrate.

[0018] The core technology of this invention lies in constructing a three-in-one bioelectrochemical response mechanism integrating corrosion signal sensing, electron transport, and corrosion inhibition triggering. When localized corrosion initiation points appear on the surface of metal components in a hydraulic system, an anodic dissolution reaction occurs in this micro-region, releasing Fe. 2+Ions cause the local pH value to drop below 5.0; this microenvironmental change is sensed by the electroactive microbial cells immobilized in the core of the microcapsule, activating their transmembrane electron transport chain, prompting the cells to transfer electrons to the electron mediator carrier through the outer membrane cytochrome c; the 2,2'-bipyridine-5,5'-dicarboxylic acid iron complex in the electron mediator carrier undergoes a reduction reaction after accepting electrons, triggering a sudden change in local redox potential; this potential change disrupts the chemical stability of the PLGA corrosion inhibitor precursor release layer, promoting its hydrolytic degradation, thereby releasing benzotriazole derivatives at specific points in the corrosion micro-area; the released benzotriazole derivatives rapidly complex with exposed copper, iron and other metal ions to form a dense, insoluble protective film, effectively blocking the corrosion propagation path.

[0019] In this process, the microbial cells themselves do not directly participate in the corrosion inhibition reaction, but only act as highly sensitive biosensors. Their metabolic activities are strictly limited by the physical barrier of the microcapsule, avoiding biological contamination of the hydraulic system caused by the leakage of live bacteria. At the same time, the mesoporous structure of the electron mediator carrier ensures the electron transfer efficiency, while the degradation rate of the PLGA release layer is positively correlated with the local acidity, realizing the dynamic matching between the amount of corrosion inhibitor released and the corrosion intensity.

[0020] The concentrated solution described in this invention is diluted in deionized water at a mass ratio of 1:20 to form a working solution. When this working solution circulates in the hydraulic support system, its biosensing microcapsules are uniformly dispersed in the liquid phase and come into contact with the metal surface along with the fluid. In non-corrosion areas, the microcapsules remain stable, and corrosion inhibitor precursors are not released; only when the local corrosion electrochemical signal reaches the threshold (defined as micro-area pH ≤ 5.5 and Fe...)... 2+ Concentration ≥10 -5 Only when the concentration reaches mol / L will the directional release mechanism be triggered. This mechanism is significantly different from the traditional constant release mode of corrosion inhibitors, enabling precise delivery and efficient utilization of corrosion inhibitor resources.

[0021] Compared with existing technologies, the advantages of this invention are as follows: By organically combining the electrochemical sensing capabilities of electroactive microorganisms with an intelligent responsive corrosion inhibition and release mechanism, this invention achieves, for the first time, in-situ identification and targeted inhibition of localized corrosion in fully synthetic hydraulic concentrates, overcoming the fundamental defects of traditional corrosion inhibition systems, such as broad-spectrum coverage and low efficiency redundancy. This technical solution not only possesses excellent corrosion protection performance and environmentally friendly characteristics, but also effectively overcomes the problem of microbial inactivation under harsh hydraulic conditions through a microencapsulation strategy, ensuring the long-term stability and engineering applicability of the system, and providing key material support for the reliable operation of green and intelligent mining equipment. Detailed Implementation

[0022] This invention provides an environmentally friendly, fully synthetic hydraulic support concentrate and its preparation method. The technical solution is based on a microbial electrochemical sensing and response mechanism, constructing an intelligent anti-rust system capable of in-situ identifying localized corrosion micro-regions and triggering targeted corrosion inhibition responses. While ensuring environmental friendliness, it significantly improves the inhibition of localized corrosion forms such as pitting and crevice corrosion, and maintains the long-term operational stability of the hydraulic system under high shear, wide temperature range, and complex working conditions. The concentrate is formulated from biosensing microcapsules, a primary corrosion inhibitor, an auxiliary corrosion inhibitor, a water-soluble lubricant, an antifoaming agent, a pH buffer, and deionized water in specific mass percentages. The components work synergistically to form a fully synthetic hydraulic medium that combines environmental compatibility, intelligent responsiveness, and engineering applicability.

[0023] The technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples, so as to ensure that those skilled in the art can fully understand and implement the present invention.

[0024] Example 1: Biosensing microcapsules 1.5%; main corrosion inhibitor 12% (sodium sebate: potassium dodecyl phosphate = 3:2); auxiliary corrosion inhibitor 4% (sodium phytate: sodium molybdate = 4:1); water-soluble lubricant 7% (polyethylene glycol monolaurate: glycerol polyoxyethylene ether = 1:1); pH buffer 2%; antifoaming agent 0.1%; preparation process: preparation of biosensing microcapsules → preparation of basic liquid phase → addition of main corrosion inhibitor → microcapsule dispersion introduction → addition of antifoaming agent → stirring and cooling → filtration → finished product.

[0025] Example 2: 0.5% biosensing microcapsules, the rest of the formulation and process are the same as in Example 1; preparation process: same as in Example 1.

[0026] Example 3: Biosensing microcapsules 3.0%, the rest of the formulation and process are the same as in Example 1; preparation process: same as in Example 1.

[0027] Example 4: 8% main corrosion inhibitor, the rest of the formulation and process are the same as in Example 1; preparation process: same as in Example 1.

[0028] Example 5: 15% main corrosion inhibitor, the rest of the formulation and process are the same as in Example 1; preparation process: same as in Example 1.

[0029] Example 6: Shear rate 1.5 × 10 4 s -1 The remaining formulas and processes are the same as in Example 1; the preparation process is the same as in Example 1 (with working condition simulation adjustment).

[0030] Example 7: Test temperature 55℃, the rest of the formula and process are the same as in Example 1; preparation process: same as in Example 1 (temperature conditions adjusted).

[0031] Example 8: The thickness of the release layer of the corrosion inhibitor precursor is 400 nm, and the rest of the formulation and process are the same as in Example 1; the preparation process is the same as in Example 1 (the thickness of the release layer is adjusted when preparing microcapsules).

[0032] Comparative Example 1: Non-biological sensing microcapsules, main corrosion inhibitor 15%, other formulations and processes are the same as in Example 1; Preparation process: basic liquid phase preparation → main corrosion inhibitor addition → antifoaming agent addition → stirring and cooling → filtration → finished product.

[0033] Comparative Example 2: Non-biosensing microcapsules, the main corrosion inhibitor is nitrite + borate (12%), the rest of the formulation and process are the same as in Example 1; preparation process: same as Comparative Example 1 (corrosion inhibitor replaced).

[0034] Test methods: Corrosion inhibition performance test: Salt spray test to determine the pitting density of 20# steel; Gravimetric method to determine the corrosion weight loss rate of brass; Rust prevention effect is evaluated with reference to industry standard MT / T76-2011.

[0035] Environmental and compatibility testing: Biodegradation rate is determined by OECD 301B standard; immersion test of seals is used to detect hardness change rate and tensile strength retention rate.

[0036] Operating condition adaptation test: Simulate high shear and wide temperature range operating conditions to measure foam height and defoaming time; test long-term operational stability.

[0037] The test data comparisons are shown in Table 1 and Table 2.

[0038] Table 1 Comparison of pitting density, brass corrosion weight loss rate, and biodegradation rate of 20# steel Table 2 Comparison of hardness change rate, foam height, and defoaming time of sealing components Examples 1-8: Pitting density ≤ 1.5 pits / cm³ 2 The biodegradation rate is ≥77%, which is far superior to the comparative example. Comparative example 1 lacks biosensing microcapsules, resulting in insufficient local corrosion inhibition. Comparative example 2 shows that the traditional corrosion inhibition system has poor environmental performance. This confirms that biosensing + targeted corrosion inhibition is the key to high efficiency and environmental protection.

[0039] Increased microcapsule addition (Examples 2→1→3) resulted in a simultaneous improvement in pitting corrosion inhibition; optimized main corrosion inhibitor ratio (Examples 4→1→5) further reduced corrosion weight loss; strong adaptability to operating conditions, maintaining stable performance under high shear and wide temperature ranges.

[0040] The embodiments comply with environmental protection standards and contain no toxic or harmful substances; they are compatible with sealing materials and suitable for hydraulic support conditions; they have excellent foam control, meeting the requirements of high-pressure and high-speed systems; and they provide long-lasting corrosion inhibition, extending the service life of equipment.

[0041] Compared to the microcapsule-free system (Comparative Example 1), the pitting density of the example was reduced by 84%, and the biodegradation rate was increased by 21%. Compared to the traditional corrosion inhibitor system (Comparative Example 2), the environmental friendliness was improved by 87%, and the corrosion inhibition effect was improved by 85%, solving the industry problem of poor local corrosion inhibition and insufficient environmental friendliness of traditional hydraulic fluids.

[0042] In summary, the concentrate described in this invention, through the synergistic effect of biosensing microcapsules and intelligent corrosion inhibition, can achieve efficient corrosion inhibition, environmental compatibility, and adaptability to working conditions with different parameter combinations, making it suitable for green mining hydraulic support systems.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly, fully synthetic hydraulic support concentrate, characterized in that, It is composed of the following components by mass percentage: 0.5%-3.0% biosensing microcapsules; 8.0%-15.0% main corrosion inhibitor; 2.0%-6.0% auxiliary corrosion inhibitor; 4.0%-10.0% water-soluble lubricant; 0.05%-0.2% antifoaming agent; 1.0%-3.0% pH buffer; and the balance being deionized water. The biosensing microcapsules have a core-shell-shell three-layer structure, with an immobilized electroactive microbial cell as the core, an electron mediator carrier as the middle layer, and an outer layer as a corrosion inhibitor precursor release layer.

2. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The immobilized electroactive microbial cells are selected from at least one of Shewanella MR-1 or Geobacter PCA, and are encapsulated in a sodium alginate-chitosan bilayer to form spherical gel microparticles.

3. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The electron mediator carrier is mesoporous silica nanoparticles loaded with ferric 2,2'-bipyridine-5,5'-dicarboxylate complex.

4. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The corrosion inhibitor precursor release layer is made by blending polylactic acid-hydroxyacetic acid copolymer and benzotriazole derivative at a mass ratio of 7:3, with a thickness of 200-500 nm.

5. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The main corrosion inhibitor is a compound of disodium sebate and potassium dodecyl phosphate, with a mass ratio of 3:2; the disodium sebate has a water solubility greater than 50 g / L; the potassium dodecyl phosphate has an alkyl chain length of C12 and a phosphate content greater than 95.0%.

6. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 5, characterized in that, The disodium sebacate has a molecular weight of 262.22, and the critical micelle concentration of the potassium dodecyl phosphate is 0.8 mmol / L.

7. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The auxiliary corrosion inhibitor is a mixture of sodium phytate and sodium molybdate in a mass ratio of 4:1; the sodium phytate has a phytic acid content greater than 85.0% and a pH value of 6.5-7.5 for a 1% aqueous solution; the sodium molybdate is a dihydrate with a molybdenum content greater than 39.0%.

8. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The water-soluble lubricant is a composite of polyethylene glycol monolaurate and glycerol polyoxyethylene ether in a mass ratio of 1:1; the polyethylene glycol monolaurate has a degree of polymerization of 20 and a hydroxyl value of 56 mgKOH / g; the glycerol polyoxyethylene ether has an ethylene oxide addition number of 15 and an HLB value of 13.

5.

9. The concentrated fluid for environmentally friendly fully synthetic hydraulic supports according to claim 1, characterized in that, The antifoaming agent is a polydimethylsiloxane emulsion with a solid content of 10% and a viscosity of 1000 mPa·s at 25°C.

10. A method for preparing a concentrated fluid for an environmentally friendly fully synthetic hydraulic support as described in any one of claims 1-9, characterized in that, The process includes the following steps: Step 1, preparation of biosensing microcapsules: Electroactive microbial cell suspension and 2% sodium alginate solution are mixed at a volume ratio of 1:4, then added dropwise to a 0.1 mol / L calcium chloride solution for solidification, followed by cross-linking with a 0.5% chitosan acetate solution to obtain immobilized cell microparticles; mesoporous silica nanoparticles are dispersed in an ethanol solution containing a 0.1 mol / L ferric 2,2'-bipyridine-5,5'-dicarboxylic acid complex, adsorbed, and then dried to obtain an electron mediator carrier; the electron mediator carrier and immobilized cell microparticles are mixed at a mass ratio of 3:1, and PLGA / benzo[a] is coated using an emulsification-solvent evaporation method. The following steps were performed: Step 1: Triazole blend solution was freeze-dried to obtain biosensing microcapsules; Step 2: Preparation of basic liquid phase: Deionized water was heated to 40°C, and pH buffer, auxiliary corrosion inhibitor, and water-soluble lubricant were added sequentially and stirred to dissolve to obtain solution A; Step 3: Addition of main corrosion inhibitor: The main corrosion inhibitor was preheated to 50°C and then slowly added to solution A, and stirred at 300 rpm for 30 minutes to obtain solution B; Step 4: Introduction of functional microcapsules: The biosensing microcapsules were ultrasonically dispersed and then added to solution B, and stirred for 20 minutes; Step 5: Addition of antifoaming agent: The antifoaming agent was added, and the mixture was stirred at 60°C and 500 rpm for 15 minutes, cooled and filtered to obtain the final product.