Dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as well as preparation method and device of dual-core temperature-sensitive multi-layer microcapsule

Abstract

The invention belongs to the technical field of fire preventing and extinguishing materials in a coal mine goaf, and discloses a dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as well as a preparation method and device of the dual-core temperature-sensitive multi-layer microcapsule. The multi-layer microcapsule comprises an outer shell formed by an oil-phase low-order temperature-sensitive wall material, a first temperature-sensitive inhibition small ball and a second temperature-sensitive inhibition small ball, the first temperature-sensitive inhibition small ball comprises a first inner-layer shell formed by an oil-phase high-order temperature-sensitive wall material and a liquid-phase acidic core material; the second temperature-sensitive inhibition small ball comprises a second inner-layer shell formed by an oil-phase high-order temperature-sensitive wall material and a liquid-phase alkaline core material; and a liquid-phase inhibitor core material is filled among the first inner-layer shell, the second inner-layer shell and the outer-layer shell. The multilayer microcapsule disclosed by the invention can be subjected to hierarchical and staged inhibition at different critical temperature sections of coal low-temperature oxidation, so that the inhibition efficiency and the inhibition effect of coal spontaneous combustion are further improved, and finally, 'inerting-inhibition 'synergistic prevention and control of coal spontaneous combustion are realized.

Description

Technical Field

[0001] The invention relates to the technical field of fire-proofing materials for coal mine goafs, and in particular to a dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal, and a preparation method and device thereof. Background Art

[0002] In the process of coal mining, coal spontaneous combustion is one of the main types of coal mine safety accidents. The fire source of coal spontaneous combustion directly or indirectly leads to mine fires, gas and dust explosions and other disasters, causing casualties and waste of coal resources, restricting the safe production and sustainable development of coal mines. Therefore, the development of efficient and new coal spontaneous combustion prevention materials is of great significance to the safe production of coal mines.

[0003] In order to reduce the risk of spontaneous combustion of coal, the current prevention and control methods for spontaneous combustion of coal include grouting, inert gas, gel, spraying of inhibitors and spraying of foam, etc. Among them, inhibitors have become the most commonly used technology to suppress spontaneous combustion of coal due to their advantages of significant fire prevention effect, convenient operation and small impact on the environment. However, traditional inhibitors have shortcomings such as easy oxidation, thermal decomposition and short action time, which lead to premature weakening of the inhibitor effect or even failure.

[0004] In order to solve the defects of the above-mentioned traditional inhibitors, those skilled in the art have proposed microencapsulation technology. For example, the prior art CN111287786A has proposed a temperature-sensitive bursting capsule inhibitor. The prior art injects the reaction material into the hole of the capsule shell and wraps it with paraffin. When the coal temperature reaches the critical temperature, the paraffin melts the reactant to generate inert gas, reduces the oxygen concentration, and inhibits the spontaneous combustion of coal. In addition, the prior art CN108729943A has proposed a temperature-sensitive microcapsule with antioxidants such as catechins, ascorbic acid, anthocyanins as core materials and polyethylene glycol as wall materials. When the coal temperature rises to the melting point of the coating layer, the wall material is heated to melt and rupture to release the core material, avoiding the premature inactivation of the antioxidant, prolonging the timeliness of the inhibition, and improving the inhibition efficiency. Although the above-mentioned several prior arts isolate the inhibitor from the external environment through microencapsulation technology, and achieve response and targeted release at a critical temperature of coal spontaneous combustion, the inhibition efficiency is improved and the inhibitor life is extended. However, as the mining location of coal mines continues to deepen, the volume of the thermosensitive material in the capsule is too large to penetrate into the deep coal rock in the goaf to achieve rapid response and inhibition of coal spontaneous combustion. At the same time, the time when the coal body reaches the critical temperature point at different coal rock depths is also different. It is difficult for single-layer microcapsules to quickly respond to and release inhibitors in stages at different critical temperature points. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a dual-core temperature-sensitive multi-layer microcapsule for inhibiting coal spontaneous combustion and a preparation method and device thereof. The multi-layer microcapsule of the present invention can penetrate into deep coal rock cracks and can release the inhibitor in stages at different stages of coal oxidation spontaneous combustion. And during the use of the multi-layer microcapsule of the present invention, if the coal temperature rises to the low-order critical temperature point, the outermost temperature-sensitive wall material is heated and melted to release the core material to chemically inhibit the coal spontaneous combustion, and at the same time releases dual-core temperature-sensitive inhibitory balls: the first temperature-sensitive inhibitory ball and the second temperature-sensitive inhibitory ball. If the coal temperature continues to rise to the high-order critical temperature point, the wall material of the dual-core temperature-sensitive inhibitory ball is heated and melted to release the acidic salt solution and the bicarbonate solution to further achieve the role of chemically inhibiting coal. At the same time, the released acidic salt solution and the bicarbonate solution react to generate a large amount of carbon dioxide inert gas, reducing the oxygen concentration, thereby achieving the role of physically and chemically compositely inhibiting coal spontaneous combustion in different layers and stages at different critical temperature points.

[0006] The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal and the preparation method and device thereof of the present invention are realized by the following technical scheme:

[0007] In order to solve the problem that it is difficult for a single-layer microcapsule to quickly respond to and release the inhibitor in stages at different critical temperature points, the present invention proposes to form a Figure 1 The microcapsules shown have a concentrically arranged multi-layer structure and are released in stages to quickly respond to different critical temperature points. However, in the subsequent exploration process, the present invention found that although the microcapsules with a concentric multi-layer structure achieve the inhibitory effect on the coal body by releasing layer by layer, the core material inhibitor released by each layer is a single type of inhibitor with a single inhibitory function, and the inhibitory effect on the coal body needs to be improved. In order to realize a composite inhibitor material that can prevent and control coal spontaneous combustion in layers and stages at different critical temperature points, and ultimately achieve the physical and chemical synergistic prevention and control of coal spontaneous combustion, the present invention provides a dual-core temperature-sensitive multi-layer microcapsule for inhibiting coal spontaneous combustion, and the multi-layer microcapsule of the present invention includes an outer shell, and a first temperature-sensitive inhibitory ball and a second temperature-sensitive inhibitory ball distributed inside the outer shell.

[0008] In the present invention, the first temperature-sensitive resistant ball includes a first inner shell, and a liquid-phase acidic core material wrapped in the first inner shell. The second temperature-sensitive resistant ball includes a second inner shell, and a liquid-phase alkaline core material wrapped in the second inner shell. And in the present invention, the liquid-phase inhibitor core material is filled between the first inner shell, the second inner shell and the outer shell. Based on the above, it can be known that the present invention arranges a dual-core temperature-sensitive resistant ball, namely a first temperature-sensitive resistant ball and a second temperature-sensitive resistant ball, and by respectively coating the liquid-phase acidic core material in the first temperature-sensitive resistant ball and coating the liquid-phase alkaline core material in the second temperature-sensitive resistant ball, so that the inhibitor core material and the liquid-phase inhibitor core material filled in the dual-core temperature-sensitive resistant ball are different inhibitor core materials and have different inhibitor functions.

[0009] Moreover, the outer shell of the present invention is formed by a low-order temperature-sensitive wall material in the oil phase; the first inner shell and the second inner shell are both formed by a high-order temperature-sensitive wall material in the oil phase, that is, the multilayer microcapsule provided by the present invention is a four-layer temperature-sensitive microcapsule containing a first temperature-sensitive retardant ball and a second temperature-sensitive retardant ball, so that when the multilayer microcapsule of the present invention is used, when the temperature of the environment reaches the low-order critical temperature point, the outer shell is heated and melted to release the liquid phase inhibitor core material. Since the liquid phase inhibitor core material is an antioxidant solution or an ionic liquid, the liquid phase inhibitor core material can capture the free radicals generated by coal oxidation, generate stable intermediates, block the coal oxidation chain reaction process, and play a role in chemically inhibiting the spontaneous combustion of coal. At the same time as chemically inhibiting the coal body, binuclear temperature-sensitive retardant balls, namely the first temperature-sensitive retardant balls and the second temperature-sensitive retardant balls, are released. If the initial inhibition of the coal body by the liquid phase inhibitor core material fails over time, and the coal oxidation continues to rise in temperature to a high-order critical temperature point, the oil phase high-order temperature-sensitive wall material of the first temperature-sensitive inhibitor ball and the second temperature-sensitive inhibitor ball will melt due to the heat, and release the liquid phase acidic core material and the liquid phase alkaline core material at the same time. The released liquid phase acidic core material and liquid phase alkaline core material will act on different coal oxidation free radicals and generate different stable groups when chemically inhibiting the coal body. In addition, the liquid phase acidic core material and the liquid phase alkaline core material will react with each other and generate a large amount of inert gas CO2 to displace the O2 in the coal pores, thereby reducing the spontaneous combustion of coal in an oxygen environment; and as the temperature rises, the reaction rate accelerates, so that more inert gas CO2 is produced, ultimately achieving the physical and chemical synergistic prevention and control of coal spontaneous combustion.

[0010] In some preferred embodiments of the present invention, the oil-phase low-level temperature-sensitive wall material is made of temperature-sensitive material, flame-retardant material and reinforcing material; wherein, based on the reinforcing material, the added amount of the temperature-sensitive material is 6.5 to 7.5 times the mass of the reinforcing material; the added amount of the flame-retardant material is 1.5 to 2.5 times the mass of the reinforcing material.

[0011] In some preferred embodiments of the present invention, the temperature-sensitive material is one or more of chlorinated paraffin, polyethylene glycol and polyvinyl chloride.

[0012] Among them, in some more preferred embodiments of the present invention, the chlorinated paraffin is one or more of 30# chlorinated paraffin to 50# chlorinated paraffin.

[0013] In some more preferred embodiments of the present invention, the flame retardant material is one or more of ammonium polyphosphate, zinc borate and aluminum hydroxide.

[0014] In some more preferred embodiments of the present invention, the reinforcing material is one or more of diatomaceous earth, montmorillonite, polyacrylamide and glass fiber.

[0015] In some preferred embodiments of the present invention, the oil phase high-order temperature-sensitive wall material is one or more of 50# chlorinated paraffin to 90# chlorinated paraffin.

[0016] In some preferred embodiments of the present invention, the antioxidant solution is prepared from an antioxidant and water; the mass fraction of the antioxidant in the antioxidant solution is 40% to 70%.

[0017] In some more preferred embodiments of the present invention, the antioxidant is one or more of rosmarinic acid, tea polyphenols, proanthocyanidins and vitamin C.

[0018] In some preferred embodiments of the present invention, the ionic liquid is an imidazole ionic liquid. In some more preferred embodiments of the present invention, the imidazole ionic liquid is one or more of 1-butyl-3-methylimidazolium nitrate, 1-butyl-3-methylimidazolium iodide, 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium tetrafluoroborate. In order to facilitate the description, 1-butyl-3-methylimidazolium nitrate is referred to as [BMIM][NO3], 1-butyl-3-methylimidazolium iodide is referred to as [BMIM][I], 1-ethyl-3-methylimidazolium tetrafluoroborate is referred to as [EMIM][BF4], and 1-butyl-3-methylimidazolium tetrafluoroborate is referred to as [BMIM][BF4].

[0019] In some preferred embodiments of the present invention, the liquid-phase acidic core material is an acidic salt solution, wherein the acidic salt solution is a phosphate solution or an acetate solution.

[0020] In some preferred embodiments of the present invention, when the acidic salt solution is a phosphate solution, the mass concentration of the phosphate solution is 15% to 20%. In some more preferred embodiments of the present invention, the phosphate used in the phosphate solution can be selected from trisodium phosphate.

[0021] In some preferred embodiments of the present invention, when the acidic salt solution is an acetate solution, the mass concentration of the acetate solution is 10% to 30%. In some more preferred embodiments of the present invention, the acetate used in the acetate solution can be selected from sodium acetate.

[0022] In some preferred embodiments of the present invention, the liquid alkaline core material is a bicarbonate aqueous solution. The bicarbonate aqueous solution is a sodium bicarbonate aqueous solution. In some more preferred embodiments of the present invention, the mass concentration of the bicarbonate aqueous solution is 10% to 20%.

[0023] The present invention also provides a method for preparing the above-mentioned dual-core temperature-sensitive multilayer microcapsules for inhibiting spontaneous combustion of coal, comprising the following steps:

[0024] Step 1, prepare the preparation device:

[0025] 1.1) Prepare a cooling device and a first double-channel injection tube, a second double-channel injection tube and a third double-channel injection tube with the same structure.

[0026] It should be noted that the first dual-channel injection tube, the second dual-channel injection tube and the third dual-channel injection tube used in the present invention all include coaxially arranged inner tube and outer tube; wherein the inner tube has a hollow structure to serve as an internal phase component delivery channel for transporting internal phase components, and there is a gap between the outer wall of the inner tube and the outer tube to form an external phase component delivery channel for transporting external phase components.

[0027] 1.2) The first dual-channel injection tube, the second dual-channel injection tube and the third dual-channel injection tube are all arranged vertically, and the first dual-channel injection tube and the second dual-channel injection tube are located at the same horizontal height, the third dual-channel injection tube is located below the first dual-channel injection tube and the second dual-channel injection tube, and the cooling device is located directly below the output end of the third dual-channel injection tube; and the output end of the first dual-channel injection tube and the output end of the second dual-channel injection tube are connected to the input end of the internal phase component transport channel in the third dual-channel injection tube through a fluid distribution array.

[0028] It should be noted that, by locating the first dual-channel injection tube and the second dual-channel injection tube at the same level, they are used to prepare the first temperature-sensitive resistant sphere and the second temperature-sensitive resistant sphere respectively.

[0029] It should also be noted that the third dual-channel injection tube is located directly below the middle position of the first dual-channel injection tube and the second dual-channel injection tube, and the cooling device is arranged directly below the output end of the third dual-channel injection tube, so that the first composite phase liquid droplet balls corresponding to the first temperature-sensitive resistant balls and the second composite phase liquid droplet balls corresponding to the second temperature-sensitive resistant balls can be simultaneously transported to the internal phase component transport channel in the dual-channel injection tube below, so that the first composite phase liquid droplet balls, the second composite phase liquid droplet balls and the liquid phase inhibitor core material can be evenly wrapped by the molten liquid of the oil phase low-order temperature-sensitive wall material to form third composite phase droplets, and finally the third composite phase droplets enter the cooling device to be cooled and solidified to obtain the multilayer microcapsules.

[0030] Step 2, preparation of the first temperature-sensitive resistant ball:

[0031] The liquid-phase acidic core material is used as the inner phase component, and the oil-phase high-order temperature-sensitive wall material is melted into an oil-phase high-order temperature-sensitive wall material molten liquid as the outer phase component, which are respectively injected into the corresponding conveying channels of the first dual-channel injection tube. Under the combined action of shear force and surface tension of the outer phase component, the inner phase component is evenly coated with a layer of oil-phase high-order temperature-sensitive wall material molten liquid on the surface of a single liquid-phase acidic core material droplet to form a first composite phase droplet ball corresponding to the first temperature-sensitive resistant ball.

[0032] Step 3, preparation of the second temperature-sensitive resistant ball:

[0033] The liquid alkaline core material is used as the inner phase component, and the oil-phase high-order temperature-sensitive wall material melt obtained by melting the oil-phase high-order temperature-sensitive wall material is used as the outer phase component, and they are respectively injected into the corresponding conveying channels of the second dual-channel injection tube. Under the combined action of shear force and surface tension of the outer phase component, the inner phase component is evenly coated with a layer of oil-phase high-order temperature-sensitive wall material melt on the surface of a single liquid alkaline core material droplet, forming a second composite phase droplet ball corresponding to the second temperature-sensitive resistant ball.

[0034] Step 4, forming multilayer microcapsules:

[0035] The first composite phase liquid droplets, the second composite phase liquid droplets and the liquid phase inhibitor core material are collectively used as the inner phase component, and the oil phase low-order temperature-sensitive wall material melt obtained by melting the oil phase low-order temperature-sensitive wall material is used as the outer phase component, and they are respectively injected into the corresponding conveying channels of the third dual-channel injection tube. Under the combined action of shear force and surface tension of the outer phase component, the inner phase component is formed into the third composite phase liquid droplets with uniform size and different solutions wrapped in a single droplet; then, the third composite phase liquid droplets fall into the cooling device to be cooled and solidified to obtain the multilayer microcapsule.

[0036] The present invention also provides a preparation device for the above preparation method, so as to realize the preparation of dual-core temperature-sensitive multi-layer microcapsules for inhibiting spontaneous combustion of coal. The preparation device of the present invention comprises a fluid distribution table, a first dual-channel injection pipe, a second dual-channel injection pipe, a third dual-channel injection pipe, two fluid distribution arrays and a cooling device.

[0037] In the present invention, three mounting seats are sequentially arranged on the fluid distribution table, among which one mounting seat is arranged in the middle of the lower end of the fluid distribution table, and the other two mounting seats are respectively arranged on both sides of the upper end of the fluid distribution table.

[0038] In the present invention, the first dual-channel injection tube and the second dual-channel injection tube are respectively vertically installed on the two mounting seats at the upper end of the fluid distribution table; the third dual-channel injection tube is installed on the mounting seat at the lower end of the fluid distribution table.

[0039] In the present invention, the input end of the cooling device is located directly below the output end of the third dual-channel injection tube.

[0040] In the present invention, the first dual-channel injection tube, the second dual-channel injection tube and the third dual-channel injection tube have the same structure, and all include an inner tube and an outer tube arranged coaxially. The inner tube has a hollow structure to serve as an inner phase component delivery channel for delivering the inner phase component. There is a gap between the outer wall of the inner tube and the outer tube to form an outer phase component delivery channel for delivering the outer phase component.

[0041] One of the fluid distribution arrays is arranged between the output end of the first dual-channel injection tube and the input end of the internal phase component delivery channel of the third dual-channel injection tube, and the other fluid distribution array is arranged between the output end of the second dual-channel injection tube and the input end of the internal phase component delivery channel of the third dual-channel injection tube.

[0042] In some preferred embodiments of the present invention, the mounting bracket is used to realize the installation and position fixation of the fluid distribution platform, the first dual-channel injection pipe, the second dual-channel injection pipe, the third dual-channel injection pipe, the two fluid distribution arrays and the cooling device. In some more preferred embodiments of the present invention, the fluid distribution platform is arranged at the upper end of the mounting bracket, and the cooling device is arranged at the bottom of the mounting bracket.

[0043] In some preferred embodiments of the present invention, the cooling device used is a liquid-connected cooling plate, and deionized water is placed in the liquid-connected cooling plate.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The dual-core temperature-sensitive coal spontaneous combustion-retardant multilayer microcapsule of the present invention comprises an outer shell, and a first temperature-sensitive retardant ball and a second temperature-sensitive retardant ball distributed inside the outer shell, wherein the first temperature-sensitive retardant ball comprises a first inner shell, and a liquid-phase acidic core material wrapped in the first inner shell. The second temperature-sensitive retardant ball comprises a second inner shell, and a liquid-phase alkaline core material wrapped in the second inner shell. The outer wall of the first inner shell, the outer wall of the second inner shell and the inner wall of the outer shell do not contact each other to form a first cavity; the first cavity is filled with a liquid-phase retardant core material. That is, the multilayer microcapsule provided by the present invention is a four-layer temperature-sensitive microcapsule containing a first temperature-sensitive resistant bead and a second temperature-sensitive resistant bead, so that when the multilayer microcapsule of the present invention is used, when the temperature of the environment reaches the low-order critical temperature point, the outer shell is heated and melted, releasing the liquid phase inhibitor core material. Since the liquid phase inhibitor core material is one or more of an antioxidant solution or an ionic liquid, the liquid phase inhibitor core material can block or inhibit the coal oxidation chain reaction process, and play the role of chemically inhibiting the spontaneous combustion of coal. And while chemically inhibiting the coal body, the dual-core temperature-sensitive resistant bead, namely the first temperature-sensitive resistant bead and the second temperature-sensitive resistant bead, will be released. If the liquid phase inhibitor core material fails to initially inhibit the coal body over time, and the coal oxidation continues to rise to a high-order critical temperature point, the oil phase high-order temperature-sensitive wall material of the first temperature-sensitive inhibitor ball and the second temperature-sensitive inhibitor ball will melt due to heat, and release the liquid phase acidic core material and liquid phase alkaline core material at the same time. The released liquid phase acidic core material and liquid phase alkaline core material will act on different coal oxidation free radicals when chemically inhibiting the coal body, and generate different stable groups, thereby achieving layered and staged inhibition in different critical temperature sections of coal low-temperature oxidation, thereby improving the inhibition efficiency and inhibition effect of coal spontaneous combustion. In addition, the liquid phase acidic core material and the liquid phase alkaline core material will also react and generate a large amount of inert gas CO2 to displace O2 in the coal pores, thereby reducing the spontaneous combustion of coal in an oxygen environment; and as the temperature rises, the reaction rate accelerates, so that the more inert gas CO2 is produced, the stronger the competitive adsorption effect with oxygen, thereby achieving the physical and chemical synergistic prevention and control of coal spontaneous combustion of "inerting-inhibiting".

[0046] The dual-core temperature-sensitive multi-layer microcapsules for preventing spontaneous combustion of coal of the present invention have a micron-level size and can penetrate into deep coal rock cracks to prevent coal bodies. In addition, the structural setting of the multi-layer microcapsules of the present invention can effectively prevent the oxidation of the inhibitor core material, thermal decomposition and short action time, prolong the timeliness of the inhibition and improve the efficiency of the inhibition.

[0047] The raw materials used in the dual-core temperature-sensitive multilayer microcapsules for inhibiting spontaneous combustion of coal of the present invention are widely available, green, environmentally friendly, non-toxic and harmless, and low in cost. The different core materials of the multilayer microcapsules of the present invention have different degrees of physical or chemical inhibition effects on the coal body. The wall materials of the multilayer microcapsules of the present invention can achieve different melting temperatures by adjusting the components and their proportions, and at the same time, flame retardant materials and reinforcing materials are added to the oil phase low-order temperature-sensitive wall materials to improve the stability and mechanical properties of the multilayer microcapsules.

[0048] The present invention uses microfluidic technology to design a preparation device. By selecting the types of core materials and wall materials, designing a coaxial dual-channel injection tube and a fluid distribution array, dual-core multi-layer microcapsules can be quickly synthesized and prepared. In view of the drawbacks of the existing microcapsule preparation process, the designed microfluidic system device has a highly integrated structure and is easy to operate, which greatly improves the coverage rate of the microcapsule core material, effectively reduces energy consumption and material consumption, and can efficiently prepare multi-layer microcapsules with uniform particle size, easily controllable functional properties, and stable morphology, thereby providing a new prevention and control measure for ensuring coal mine safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the structure of coaxially arranged multi-layer microcapsules prepared in Comparative Example 1; Figure 1 In the figure, B is the outermost shell formed by the low-order temperature-sensitive wall material of the oil phase, B1 is the inner shell formed by the high-order temperature-sensitive wall material of the oil phase, X is the outer layer inhibitor core material, and X1 is the inner layer inhibitor core material.

[0050] Figure 2 is a schematic diagram of the structure of the multilayer microcapsule of the present invention; Figure 2 In the figure, B is the outer shell, X is the liquid phase inhibitor core material, Q1 is the first temperature sensitive inhibitor ball, Q2 is the second temperature sensitive inhibitor ball, B1 is the first inner shell, B2 is the second inner shell, X1 is the liquid phase acidic core material, and X2 is the liquid phase alkaline core material.

[0051] Figure 3 Schematic diagram of the inhibition mechanism of the multilayer microcapsules of the present invention.

[0052] Figure 4 The main preparation flow chart of the multilayer microcapsules of the present invention.

[0053] Figure 5 It is a schematic diagram of the structure of the preparation device of the present invention. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0055] Example 1

[0056] See also Figure 2, this embodiment provides a dual-core temperature-sensitive multilayer microcapsule for inhibiting spontaneous combustion of coal. The multilayer microcapsule of this embodiment includes an outer shell B, and a first temperature-sensitive resistant ball Q1 and a second temperature-sensitive resistant ball Q2 distributed inside the outer shell. Among them, the first temperature-sensitive resistant ball Q1 includes a first inner shell B1, and a liquid-phase acidic core material X1 wrapped in the first inner shell B1. The second temperature-sensitive resistant ball Q2 includes a second inner shell B2, and a liquid-phase alkaline core material X2 wrapped in the second inner shell B2; wherein, the first inner shell B1, the second inner shell B2 and the outer shell B do not contact each other to form a cavity structure, and the cavity structure is filled with a liquid-phase inhibitor core material X.

[0057] It should be noted that the dual-core temperature-sensitive multi-layer microcapsules for inhibiting spontaneous combustion of coal provided in this embodiment are aimed at spontaneous combustion coal layers under uneven temperature, and the total number of layers is set to four.

[0058] In the four-layer structure of the multilayer microcapsule of this embodiment, the first layer from the outside to the inside is the outer shell B. The outer shell B in this embodiment is formed by an oil-phase low-order temperature-sensitive wall material, and the oil-phase low-order temperature-sensitive wall material of this embodiment is formed by a mixture of 40# chlorinated paraffin, ammonium polyphosphate and glass fiber, and the added amount of 40# chlorinated paraffin is 7 times the mass of the glass fiber, and the added amount of ammonium polyphosphate is 2 times the mass of the glass fiber, so that the melting point of the outer shell B in this embodiment is about 40°C.

[0059] The second layer is a liquid phase inhibitor core material X disposed between the first temperature sensitive resistant ball Q1, the second temperature sensitive resistant ball Q2 and the outer shell B. The liquid phase inhibitor core material X in this embodiment is a tea polyphenol aqueous solution with a mass fraction of 70%.

[0060] The third layer is the first inner shell B1 in the first temperature-sensitive resistant ball Q1, and the second inner shell B2 in the second temperature-sensitive resistant ball Q2. In this embodiment, the first inner shell B1 and the second inner shell B2 are both 70# chlorinated paraffin, so that the melting points of the first inner shell B1 and the second inner shell B2 in this embodiment are both around 70°C.

[0061] The fourth layer is the liquid acidic core material X1 wrapped in the first inner shell B1, and the liquid alkaline core material X2 wrapped in the second inner shell B2. In this embodiment, the liquid acidic core material X1 is a phosphate solution with a mass concentration of 18%, and the liquid alkaline core material X2 is a sodium bicarbonate solution with a mass concentration of 15%.

[0062] Based on the above, it can be known that the multilayer microcapsule of this embodiment is a four-layer temperature-sensitive microcapsule containing a first temperature-sensitive resistant sphere and a second temperature-sensitive resistant sphere, so that when the multilayer microcapsule of the present invention is used, the materials of the first layer to the fourth layer are released step by step to effectively prevent and control the spontaneous combustion of coal. Figure 3 When the multilayer microcapsules of this embodiment are used for the prevention and control of coal spontaneous combustion, when the coal temperature rises to the low-order critical temperature point of about 40°C, the first layer material of the multilayer microcapsules of this embodiment, that is, the outer shell B, is heated and melted, thereby releasing the second layer material, that is, the liquid phase inhibitor core material X, and at the same time releasing dual-core high-order temperature-sensitive inhibitor balls, that is, the first temperature-sensitive inhibitor ball Q1 and the second temperature-sensitive inhibitor ball Q2. The liquid phase inhibitor core material X is a tea polyphenol solution, which can form a thin film on the surface of the coal, which has the effect of wetting the coal body to physically inhibit the spontaneous combustion of the coal. At the same time, the tea polyphenol solution captures free radicals in the coal through chemical reactions to generate stable intermediates, blocking the coal oxidation chain reaction process, and having the effect of chemically inhibiting the spontaneous combustion of the coal. If the initial physical and chemical inhibition of the tea polyphenol solution fails over time, when the coal temperature rises to 70°C, the third layer material of the multilayer microcapsule of this embodiment, i.e., the first inner shell B1 in the first temperature-sensitive resistant ball Q1, and the second inner shell B2 in the second temperature-sensitive resistant ball Q2, melt by heat, and release the fourth layer material, i.e., the phosphate solution as the liquid acidic core material X1 and the sodium bicarbonate solution as the liquid alkaline core material X2. Among them, the phosphate solution as the liquid acidic core material X1 inhibits the generation of hydroxyl radicals in the coal and promotes the formation of stable saturated ether bonds, thereby achieving the effect of chemically inhibiting the spontaneous combustion of coal. At the same time, the phosphate solution as the liquid acidic core material X1 can also react with the sodium bicarbonate solution of the liquid alkaline core material X2 to generate a large amount of inert gas CO2, displace the O2 in the coal pores, and physically inhibit the spontaneous combustion of coal, and finally achieve the effect of physically and chemically compounding the spontaneous combustion of coal at different critical temperature points in different layers and stages.

[0063] It should also be noted that when the phosphate solution is in excess, the reaction equation of the phosphate solution of the liquid acidic core material X1 and the sodium bicarbonate solution of the liquid alkaline core material X2 is as shown in Formula 1.

[0064] NaHCO3+H3PO4→NaH2PO4+H2O+CO2↑Formula 1.

[0065] When the sodium bicarbonate solution is in excess, the reaction equation of the phosphate solution of the liquid acidic core material X1 and the sodium bicarbonate solution of the liquid alkaline core material X2 is as shown in Formula 2.

[0066] 2NaHCO3+H3PO4→Na2HPO4+2H2O+2CO2↑Formula 2.

[0067] See also Figure 4 The method for preparing the multilayer microcapsules of this embodiment comprises the following steps:

[0068] Step 1, prepare the preparation device:

[0069] 1.1) Prepare a cooling device and a first dual-channel injection tube 1, a second dual-channel injection tube 2 and a third dual-channel injection tube 3 with the same structure. The first dual-channel injection tube 1, the second dual-channel injection tube 2 and the third dual-channel injection tube 3 each include a coaxially arranged inner tube 4 and an outer tube 5, wherein the inner tube 4 serves as an inner phase component delivery channel, and the gap between the outer wall of the inner tube 4 and the outer tube 5 serves as an outer phase component delivery channel.

[0070] 1.2) The first dual-channel injection tube 1, the second dual-channel injection tube 2 and the third dual-channel injection tube 3 are all arranged vertically, and the first dual-channel injection tube 1 and the second dual-channel injection tube 2 are located at the same horizontal height, the third dual-channel injection tube 3 is located below the first dual-channel injection tube 1 and the second dual-channel injection tube 2, and the cooling device is located directly below the output end of the third dual-channel injection tube 3. The output end of the first dual-channel injection tube 1 and the output end of the second dual-channel injection tube 2 are connected to the input end of the internal phase component delivery channel in the third dual-channel injection tube 3 through the fluid distribution array 8.

[0071] Step 2, preparation of the first temperature-sensitive resistant ball Q1:

[0072] 2.1) Dissolve trisodium phosphate in deionized water to obtain a phosphate aqueous solution with a mass concentration of 18% as a liquid acidic core material.

[0073] 2.2) Heat 70# chlorinated paraffin at 70°C to a molten state to obtain an oil phase high-order temperature-sensitive wall material molten liquid.

[0074] 2.3) The liquid-phase acidic core material is injected into the inner phase component delivery channel of the first dual-channel injection tube 1, and the oil-phase high-order temperature-sensitive wall material melt is injected into the outer phase component delivery channel of the first dual-channel injection tube 1. Since the inner tube 4 and the outer tube 5 are coaxially arranged, the inner phase component is uniformly wrapped with a layer of oil-phase high-order temperature-sensitive wall material melt on the surface of a single liquid-phase acidic core material droplet of the inner phase component under the combined action of shear force and surface tension of the outer phase component, thereby forming a first composite phase droplet ball corresponding to the first temperature-sensitive resistant ball Q1.

[0075] Step 3, preparation of the second temperature-sensitive resistant ball:

[0076] 3.1) Sodium bicarbonate is fully dissolved in deionized water to obtain a liquid alkaline core material with a mass concentration of 15%.

[0077] 3.2) Heat 70# chlorinated paraffin at 70°C to a molten state to obtain an oil phase high-order temperature-sensitive wall material molten liquid.

[0078] 3.3) The liquid alkaline core material prepared in step 3.1) is injected into the inner phase component delivery channel of the second dual-channel injection tube 2, and the oil-phase high-order temperature-sensitive wall material melt is injected into the outer phase component delivery channel of the second dual-channel injection tube 2. Since the inner tube 4 and the outer tube 5 are coaxially arranged, the inner phase component is uniformly wrapped with a layer of oil-phase high-order temperature-sensitive wall material melt on the surface of a single liquid alkaline core material droplet of the inner phase component under the combined action of shear force and surface tension of the outer phase component, thereby forming a second composite phase droplet ball corresponding to the second temperature-sensitive resistant ball Q2.

[0079] It should be emphasized that the above steps 2.2) and 3.3) are performed synchronously.

[0080] Step 4, forming multilayer microcapsules:

[0081] 4.1) Dispersing tea polyphenols in deionized water to form a tea polyphenol aqueous solution with a mass fraction of 70% as a liquid phase inhibitor core material.

[0082] 4.2) 40# chlorinated paraffin, ammonium polyphosphate and glass fiber are mixed according to the above ratio, and heated to a molten state at a temperature of 70°C to obtain an oil phase low-order temperature-sensitive wall material molten liquid.

[0083] 4.3) The first composite phase droplet ball obtained in step 2.2), the second temperature-sensitive inhibitor ball obtained in step 3.3) and the liquid phase inhibitor core material obtained in step 4.1) are used together as the inner phase component, and the molten liquid of the low-order temperature-sensitive wall material in the oil phase obtained in step 4.2) is used as the outer phase component, and the inner phase component is injected into the inner phase component delivery channel of the third dual-channel injection tube 3, and the molten liquid of the low-order temperature-sensitive wall material in the oil phase is injected into the outer phase component delivery channel of the third dual-channel injection tube 3. The outer tube 5 is coaxially arranged so that under the combined action of shear force and surface tension of the outer phase component, a layer of molten oil-phase low-order temperature-sensitive wall material is evenly wrapped on the surface of a single droplet of the inner phase component to form a third composite phase droplet ball. The composite phase droplet ball falls into the cooling device 9 below it for cooling treatment until the outermost layer of the molten oil-phase low-order temperature-sensitive wall material in the third composite phase droplet ball is cooled and solidified to form an outer shell, which is then filtered to obtain the multilayer microcapsules of this embodiment.

[0084] Example 2

[0085] This embodiment provides a dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal.

[0086] See also Figure 2 It can be seen that, for the spontaneous combustion coal layer under non-uniform temperature, the total number of layers of the dual-core temperature-sensitive multi-layer microcapsules for inhibiting spontaneous combustion of coal provided in this embodiment is four.

[0087] In the multilayer microcapsule of the present embodiment, the first layer from the outside to the inside is the outer shell B. The outer shell B in the present embodiment is formed by an oil phase low-order temperature-sensitive wall material, and the oil phase low-order temperature-sensitive wall material of the present embodiment is formed by a mixture of 50# chlorinated paraffin, zinc borate and diatomaceous earth, and the added amount of 50# chlorinated paraffin is 7 times the mass of diatomaceous earth, and the added amount of zinc borate is 2 times the mass of diatomaceous earth, so that the melting point of the outer shell B in the present embodiment is about 50°C.

[0088] The second layer is a liquid phase inhibitor core material X disposed between the first temperature sensitive resistant ball Q1, the second temperature sensitive resistant ball Q2 and the outer shell B. The liquid phase inhibitor core material X in this embodiment is an ionic liquid [BMIM][BF4].

[0089] The third layer is the first inner shell B1 in the first temperature-sensitive resistant ball Q1, and the second inner shell B2 in the second temperature-sensitive resistant ball Q2. In this embodiment, the first inner shell B1 and the second inner shell B2 are both 80# chlorinated paraffin, so that the melting points of the first inner shell B1 and the second inner shell B2 in this embodiment are both around 80°C.

[0090] The fourth layer is the liquid acidic core material X1 wrapped in the first inner shell B1, and the liquid alkaline core material X2 wrapped in the second inner shell B2. In this embodiment, the liquid acidic core material X1 is an acetate solution with a mass concentration of 20%, and the liquid alkaline core material X2 is a sodium bicarbonate solution with a mass concentration of 15%.

[0091] Based on the above, it can be known that the multilayer microcapsule of the present embodiment is a four-layer temperature-sensitive microcapsule containing a first temperature-sensitive resistant ball and a second temperature-sensitive resistant ball, so that the multilayer microcapsule of the present invention can effectively prevent and control coal spontaneous combustion by gradually releasing the materials from the first layer to the fourth layer when used. Specifically, when the multilayer microcapsule of the present embodiment is used for coal spontaneous combustion prevention and control, when the coal temperature rises to the low-order critical temperature point of about 50°C, the first layer material of the multilayer microcapsule of the present embodiment, that is, the outer shell B, is heated and melted, thereby releasing the second layer material, that is, the liquid phase inhibitor core material X, and at the same time releasing the dual-core high-order temperature-sensitive resistant ball, that is, the first temperature-sensitive resistant ball Q1 and the second temperature-sensitive resistant ball Q2. The liquid phase inhibitor core material X is an ionic liquid [BMIM][BF4] that can dissolve and destroy the active groups in the coal, inhibit the process of coal oxidation reaction, and play an effect of chemically inhibiting coal spontaneous combustion. If the initial physical and chemical inhibition of the ionic liquid [BMIM][BF4] fails over time, when the coal temperature rises to 70°C, the third layer material of the multilayer microcapsule of this embodiment, i.e., the first inner shell B1 in the first temperature-sensitive resistant ball Q1, and the second inner shell B2 in the second temperature-sensitive resistant ball Q2, melt by heat, and release the fourth layer material, i.e., the acetate solution as the liquid acidic core material X1 and the sodium bicarbonate solution as the liquid alkaline core material X2. Among them, the acetate solution as the liquid acidic core material X1 inhibits the generation of hydroxyl radicals in the coal and promotes the formation of stable saturated ether bonds, thereby achieving the effect of chemically inhibiting the spontaneous combustion of coal. At the same time, the acetate solution as the liquid acidic core material X1 can also react with the sodium bicarbonate solution of the liquid alkaline core material X2 to generate a large amount of inert gas CO2, thereby being able to displace the O2 in the coal pores, physically inhibiting the spontaneous combustion of coal, and finally achieving the effect of physically and chemically compositely inhibiting the spontaneous combustion of coal at different critical temperature points in different layers and stages.

[0092] It should also be noted that the reaction equation of the acetate solution of the liquid acidic core material X1 and the sodium bicarbonate solution of the liquid alkaline core material X2 is shown in Formula 3.

[0093] CH3COOH+NaHCO3→CH3COONa+H2O+CO2↑Equation 3.

[0094] See also Figure 4 The method for preparing the multilayer microcapsules of this embodiment comprises the following steps:

[0095] Step 1, prepare the preparation device:

[0096] 1.1) Prepare a cooling device and a first dual-channel injection tube 1, a second dual-channel injection tube 2 and a third dual-channel injection tube 3 with the same structure. The first dual-channel injection tube 1, the second dual-channel injection tube 2 and the third dual-channel injection tube 3 each include a coaxially arranged inner tube 4 and an outer tube 5, wherein the inner tube 4 serves as an inner phase component delivery channel, and the gap between the outer wall of the inner tube 4 and the outer tube 5 serves as an outer phase component delivery channel.

[0097] 1.2) The first dual-channel injection tube 1, the second dual-channel injection tube 2 and the third dual-channel injection tube 3 are all arranged vertically, and the first dual-channel injection tube 1 and the second dual-channel injection tube 2 are located at the same horizontal height, the third dual-channel injection tube 3 is located below the first dual-channel injection tube 1 and the second dual-channel injection tube 2, and the cooling device is located directly below the output end of the third dual-channel injection tube 3. The output end of the first dual-channel injection tube 1 and the output end of the second dual-channel injection tube 2 are connected to the input end of the internal phase component delivery channel in the third dual-channel injection tube 3 through the fluid distribution array 8.

[0098] Step 2, preparation of the first temperature-sensitive resistant ball Q1:

[0099] 2.1) Sodium acetate is fully dissolved in deionized water to obtain a liquid acidic core material with a mass concentration of 20%.

[0100] 2.2) Heat 80# chlorinated paraffin at 70°C to a molten state to obtain an oil phase high-order temperature-sensitive wall material molten liquid.

[0101] 2.3) The liquid-phase acidic core material is injected into the inner phase component delivery channel of the first dual-channel injection tube 1, and the oil-phase high-order temperature-sensitive wall material melt is injected into the outer phase component delivery channel of the first dual-channel injection tube 1. Since the inner tube 4 and the outer tube 5 are coaxially arranged, the inner phase component is subjected to the combined action of shear force and surface tension of the outer phase component, so that a layer of oil-phase high-order temperature-sensitive wall material melt is evenly wrapped on the surface of a single liquid-phase acidic core material droplet, forming a first composite phase droplet ball corresponding to the first temperature-sensitive resistant ball Q1.

[0102] Step 3, preparation of the second temperature-sensitive resistant ball:

[0103] 3.1) Sodium bicarbonate is fully dissolved in deionized water to obtain a liquid alkaline core material with a mass concentration of 15%.

[0104] 3.2) Heat 80# chlorinated paraffin at 80°C to a molten state to obtain an oil phase high-order temperature-sensitive wall material molten liquid.

[0105] 3.3) The liquid alkaline core material prepared in step 3.1) is injected into the inner phase component delivery channel of the second dual-channel injection tube 2, and the oil-phase high-order temperature-sensitive wall material melt is injected into the outer phase component delivery channel of the second dual-channel injection tube 2. Since the inner tube 4 and the outer tube 5 are coaxially arranged, the inner phase component is subjected to the combined action of shear force and surface tension of the outer phase component, so that a layer of oil-phase high-order temperature-sensitive wall material melt is evenly wrapped on the surface of a single liquid alkaline core material droplet, thereby forming a second composite phase droplet ball corresponding to the second temperature-sensitive resistant ball Q2.

[0106] It should be emphasized that the above steps 2.2) and 3.3) are performed synchronously.

[0107] Step 4, forming multilayer microcapsules:

[0108] 4.1) Use an electronic balance to accurately weigh the [BMIM][BF4] solution as the liquid phase inhibitor core material.

[0109] 4.2) 50# chlorinated paraffin, zinc borate and diatomaceous earth are mixed according to the above ratio, and heated to a molten state at a temperature of 70°C to obtain an oil phase low-order temperature-sensitive wall material molten liquid.

[0110] 4.3) The first composite phase droplet ball obtained in step 2.2), the second temperature-sensitive inhibitor ball obtained in step 3.3) and the liquid phase inhibitor core material obtained in step 4.1) are used together as the inner phase component, and the molten liquid of the low-order temperature-sensitive wall material in the oil phase obtained in step 4.2) is used as the outer phase component, and the inner phase component is injected into the inner phase component delivery channel of the third dual-channel injection tube 3, and the molten liquid of the low-order temperature-sensitive wall material in the oil phase is injected into the outer phase component delivery channel of the third dual-channel injection tube 3. The outer tube 5 is coaxially arranged so that the inner phase component is evenly coated with a layer of molten oil-phase low-order temperature-sensitive wall material on the surface of a single inner phase component droplet under the combined action of shear force and surface tension of the outer phase component to form a third composite phase droplet ball. The composite phase droplet ball falls into the cooling device below it for cooling treatment until the outermost layer of the molten oil-phase low-order temperature-sensitive wall material of the third composite phase droplet ball is cooled and solidified to form an outer shell, which is then filtered to obtain the multilayer microcapsule of this embodiment.

[0111] Example 3

[0112] This embodiment provides a preparation device, which is used for preparing the dual-core temperature-sensitive multi-layer microcapsules for inhibiting coal spontaneous combustion in Embodiment 1 and Embodiment 2.

[0113] See also Figure 5 The preparation device of this embodiment includes a mounting bracket 6, a fluid distribution platform 7, a first dual-channel injection tube 1, a second dual-channel injection tube 2, a third dual-channel injection tube 3, two fluid distribution arrays 8 and a cooling device 9.

[0114] See also Figure 5 In this embodiment, the fluid distribution platform 7 is disposed at the upper end of the mounting bracket 6, and three mounting seats 10 are disposed on the fluid distribution platform 7. Among the three mounting seats, one mounting seat 10 is disposed in the middle of the lower end of the fluid distribution platform 7, and the other two mounting seats 10 are respectively located on both sides of the upper end of the fluid distribution platform 7.

[0115] The first dual-channel injection tube 1 and the second dual-channel injection tube 2 are respectively vertically installed on the two mounting seats 10 at the upper end of the fluid distribution platform 7; the third dual-channel injection tube 3 is installed on the mounting seat 10 at the lower end of the fluid distribution platform 7.

[0116] The cooling device 9 is arranged at the bottom of the mounting bracket 6, and the input end of the cooling device 9 is located directly below the output end of the third dual-channel injection tube 3, so that the third composite phase droplet spheres formed by the third dual-channel injection tube 3 fall into the cooling device 9 for cooling and solidification to obtain the multilayer microcapsules.

[0117] The first dual-channel injection tube 1 , the second dual-channel injection tube 2 and the third dual-channel injection tube 3 have the same structure, and all include an inner tube 4 and an outer tube 5 that are coaxially arranged.

[0118] The inner tube 4 has a hollow structure for conveying the inner phase component, and an outer phase component conveying channel for conveying the outer phase component is formed between the outer wall of the inner tube 4 and the outer tube 5 .

[0119] One of the fluid distribution arrays 8 is arranged between the output end of the first dual-channel injection tube 1 and the input end of the inner tube 4 of the third dual-channel injection tube 3, and the other fluid distribution array 8 is arranged between the output end of the second dual-channel injection tube 2 and the input end of the inner tube 4 of the third dual-channel injection tube 3.

[0120] When using the preparation device of this embodiment to prepare dual-core temperature-sensitive multilayer microcapsules that inhibit spontaneous combustion of coal, syringes are connected to the input ends of the inner tube 4 and the external phase component delivery channel of the first dual-channel injection tube 1 and the second dual-channel injection tube 2, and each syringe is filled with a corresponding internal phase component or external phase component, so as to facilitate the injection of the corresponding internal phase component or external phase component through the corresponding syringe. It should be noted that the operation of connecting the syringe to inject the internal phase component or the external phase component belongs to the conventional means in the field, and those skilled in the art should know it, so the present invention will not be repeated here.

[0121] In a preferred embodiment of the present invention, the cooling device 9 is a liquid-contacting cooling plate, and deionized water is placed in the liquid-contacting cooling plate.

[0122] Comparative Example 1

[0123] This comparative example is a microcapsule with a concentrically arranged multilayer structure proposed by the present invention in the early stage of exploration.

[0124] See also Figure 1 The microcapsules in this comparative example also have a four-layer structure, that is, this comparative example provides a concentric four-layer microcapsule.

[0125] Depend on Figure 1 It can be seen that the outer shell B in this comparative example is formed by an oil-phase low-order temperature-sensitive wall material, and the oil-phase low-order temperature-sensitive wall material of this embodiment is formed by a mixture of 40# chlorinated paraffin, ammonium polyphosphate and glass fiber, and the added amount of 40# chlorinated paraffin is 7 times the mass of the glass fiber, and the added amount of ammonium polyphosphate is 2 times the mass of the glass fiber, so that the melting point of the outer shell B of this embodiment is about 40°C.

[0126] The second layer is a liquid phase inhibitor core material X, and the liquid phase inhibitor core material X is a tea polyphenol aqueous solution with a mass fraction of 70%.

[0127] The third layer is the inner shell B1 in the temperature-sensitive resistant ball. The inner shell B1 is 70# chlorinated paraffin, so that the melting point of the inner shell of this comparative example is about 70°C.

[0128] The fourth layer is a liquid-phase acidic core material X1 wrapped in the inner shell B1, and the liquid-phase acidic core material X1 is a vitamin C aqueous solution with a mass fraction of 70%.

[0129] The preparation method of the microcapsules of this comparative example is different from Example 1 only in that:

[0130] Only one dual-channel injection tube is used, and the other preparation steps are the same as those in Example 1, thereby obtaining Figure 1 The microcapsule structure shown.

[0131] Based on the above, it can be known that the microcapsules of this comparative example are similar to those of Example 1, and can also be used to prevent and control coal spontaneous combustion through the step-by-step release of materials from the first layer to the fourth layer. However, when the microcapsules of this comparative example are in use, if the initial physical and chemical inhibition of the tea polyphenol solution fails over time, and the coal temperature rises to 70°C, the microcapsule oil phase high-order temperature-sensitive wall material B1 melts due to heat, and can only release a single liquid phase acidic core material X1 to perform a certain degree of chemical inhibition, and cannot achieve the inerting effect of generating CO2 gas in Example 1 of the present invention, that is, the comparative example cannot achieve the "inerting-inhibiting" coal spontaneous combustion effect of the present invention.

[0132] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal, characterized in that: It comprises an outer shell, and a first temperature-sensitive resistant ball and a second temperature-sensitive resistant ball distributed inside the outer shell; The first temperature-sensitive resistant ball comprises a first inner shell and a liquid-phase acidic core material wrapped in the first inner shell; The second temperature-sensitive resistant ball comprises a second inner shell and a liquid alkaline core material wrapped in the second inner shell; Wherein, a liquid phase inhibitor core material is filled between the first inner shell, the second inner shell and the outer shell; The outer shell is formed of oil-phase low-level temperature-sensitive wall material; The first inner shell and the second inner shell are both formed of oil-phase high-order temperature-sensitive wall materials; The liquid phase inhibitor core material is an antioxidant solution or an ionic liquid.

2. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 1, characterized in that: The oil-phase low-level temperature-sensitive wall material is made of temperature-sensitive material, flame-retardant material and reinforcing material; wherein, based on the reinforcing material, the added amount of the temperature-sensitive material is 6.5 to 7.5 times the mass of the reinforcing material; the added amount of the flame-retardant material is 1.5 to 2.5 times the mass of the reinforcing material.

3. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 2, characterized in that: The temperature-sensitive material is one or more of chlorinated paraffin, polyethylene glycol and polyvinyl chloride; Wherein, the chlorinated paraffin is one or more of 30# chlorinated paraffin to 50# chlorinated paraffin; The flame retardant material is one or more of ammonium polyphosphate, zinc borate and aluminum hydroxide; The reinforcing material is one or more of diatomaceous earth, montmorillonite, polyacrylamide and glass fiber.

4. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 1, characterized in that: The oil phase high-order temperature-sensitive wall material is one or more of 50# chlorinated paraffin to 90# chlorinated paraffin.

5. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 1, characterized in that: The antioxidant solution is prepared from an antioxidant and water; The mass fraction of the antioxidant in the antioxidant solution is 40% to 70%; The antioxidant is one or more of rosmarinic acid, tea polyphenols, proanthocyanidins and vitamin C.

6. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 1, characterized in that: The ionic liquid is an imidazole ionic liquid.

7. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 1, characterized in that: The liquid-phase acidic core material is an acidic salt solution.

8. The dual-core temperature-sensitive multi-layer microcapsule for inhibiting spontaneous combustion of coal as claimed in claim 1, characterized in that: The liquid alkaline core material is a bicarbonate aqueous solution.

9. A method for preparing the dual-core temperature-sensitive multi-layer microcapsules for inhibiting spontaneous combustion of coal according to any one of claims 1 to 8, characterized in that: The following steps are involved: Prepare a preparation device: prepare a cooling device and a first dual-channel injection tube (1), a second dual-channel injection tube (2) and a third dual-channel injection tube (3) having the same structure; the first dual-channel injection tube (1), the second dual-channel injection tube (2) and the third dual-channel injection tube (3) all include an inner tube (4) and an outer tube (5) arranged coaxially; the inner tube (4) serves as an inner phase component conveying channel, and an outer phase component conveying channel is formed between the outer wall of the inner tube (4) and the outer tube (5); the first dual-channel injection tube (1), the second dual-channel injection tube (2) and the third dual-channel injection tube (3) are The channel injection pipes (3) are all arranged vertically, the first dual-channel injection pipe (1) and the second dual-channel injection pipe (2) are located at the same horizontal height, the third dual-channel injection pipe (3) is arranged below the first dual-channel injection pipe (1) and the second dual-channel injection pipe (2), and the cooling device is arranged directly below the output end of the third dual-channel injection pipe (3); the output end of the first dual-channel injection pipe (1) and the output end of the second dual-channel injection pipe (2) are respectively connected to the input end of the internal phase component transport channel in the third dual-channel injection pipe (3) through the fluid distribution array (8); The liquid phase acidic core material is used as the inner phase component, and the molten oil phase high-order temperature-sensitive wall material obtained by melting the oil phase high-order temperature-sensitive wall material is used as the outer phase component, and they are respectively injected into the corresponding delivery channels of the first dual-channel injection tube (1) to form the first composite phase liquid droplet sphere corresponding to the first temperature-sensitive resistant sphere; The liquid alkaline core material is used as the inner phase component, and the molten oil-phase high-order temperature-sensitive wall material obtained by melting the oil-phase high-order temperature-sensitive wall material is used as the outer phase component, and they are respectively injected into the corresponding delivery channels of the second dual-channel injection tube (2) to form second composite phase liquid droplets corresponding to the second temperature-sensitive resistant beads; The first composite phase liquid droplets, the second composite phase liquid droplets and the liquid phase inhibitor core material are used together as the inner phase component, and the molten liquid obtained by melting the oil phase low-order temperature-sensitive wall material is used as the outer phase component, and are respectively injected into the corresponding conveying channels of the third dual-channel injection tube (3) to form third composite phase liquid droplets; the formed third composite phase liquid droplets fall into the cooling device to be cooled and solidified to obtain the multilayer microcapsule.

10. A preparation device for the preparation method according to claim 9, characterized in that: It comprises a fluid distribution platform (7), a first dual-channel liquid injection pipe (1), a second dual-channel liquid injection pipe (2), a third dual-channel liquid injection pipe (3), two fluid distribution arrays (8) and a cooling device (9); Three mounting seats (10) are arranged in sequence on the fluid distribution platform (7), one mounting seat (10) is arranged in the middle of the lower end of the fluid distribution platform (7), and the other two mounting seats (10) are respectively arranged on both sides of the upper end of the fluid distribution platform (7); The first dual-channel injection pipe (1) and the second dual-channel injection pipe (2) are respectively vertically mounted on the two mounting seats (10) located at the upper end of the fluid distribution platform (7); the third dual-channel injection pipe (3) is mounted on the mounting seat (10) located at the lower end of the fluid distribution platform (7); The input end of the cooling device (9) is located directly below the output end of the third dual-channel injection pipe (3); Wherein, the first dual-channel injection tube (1), the second dual-channel injection tube (2) and the third dual-channel injection tube (3) have the same structure, and all comprise an inner tube (4) and an outer tube (5) which are coaxially arranged; The inner tube (4) has a hollow structure to serve as an inner phase component delivery channel, and there is a gap between the inner tube (4) and the outer tube (5) to form an outer phase component delivery channel; One of the fluid distribution arrays (8) is arranged between the output end of the first dual-channel injection tube (1) and the input end of the internal phase component delivery channel of the third dual-channel injection tube (3), and the other fluid distribution array (8) is arranged between the output end of the second dual-channel injection tube (2) and the input end of the internal phase component delivery channel of the third dual-channel injection tube (3).

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