Liquid polymer stopping agent for coal mine and preparation method of liquid polymer stopping agent

Abstract

The invention belongs to the technical field of antioxidants, and discloses a liquid polymer stopping agent for a coal mine and a preparation method of the liquid polymer stopping agent. The invention provides a preparation method of a liquid polymer inhibitor for a coal mine. The preparation method comprises the following steps: copolymerizing an acrylate compound to obtain a hydrophobic acrylate polymer; and placing the hydrophobic acrylate polymer in a solution environment containing a hydrophilic polymer precursor, a cross-linking agent, a surfactant, an antioxidant and a solvent, and cooling to room temperature after the heating reaction is finished to obtain the liquid polymer stopping agent. The hydrophobic polymer and the hydrophilic polymer are adopted to obtain the liquid polymer inhibitor through an interpenetrating network, and the technical problems that a traditional inorganic oxygen barrier fire extinguishing agent is low in inhibition rate and prone to failure at high temperature are effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of antioxidants and discloses a liquid polymer inhibitor for coal mines and a preparation method thereof. Background Art

[0002] In chemistry, any substance that can reduce the rate of a chemical reaction is called an inhibitor. Inhibitors are chemical agents that prevent coal from oxidizing and spontaneously combusting, and are also called oxidation inhibitors or antioxidants. Inhibitor fire prevention technology uses certain inorganic salt compounds that can inhibit coal oxidation, such as calcium chloride, magnesium chloride, ammonium chloride, water glass, etc., which are sprayed into the goaf or injected into the coal body to inhibit or delay the oxidation of coal, thereby preventing coal from spontaneously combusting. Currently, commonly used inhibitors include calcium chloride, magnesium chloride, table salt, and certain industrial waste liquids. For example, CN101487399B provides an inhibitor that can prevent coal from spontaneously combusting and a preparation method, which is composed of the following chemical raw materials, by weight: 88 parts of magnesium chloride; 4 parts of sodium tetraborate and sodium gluconate mixed in any ratio of 1:9 to 6:4, and 8 parts of sodium lauryl sulfate. However, the commonly used inhibitors are corrosive to equipment, pipelines, etc., and the nozzles generally need to be replaced every 2 to 3 months; they dehydrate quickly, have a short water retention time, a short inhibitor life, are easy to volatilize, have a low inhibitory rate, and the inhibitory effect is greatly reduced as the temperature rises. The fire prevention effect is average, and the fire extinguishing effect is even less ideal; the addition ratio is generally 10 to 20%, the transportation volume is large, the worker operation labor is heavy, and it is very irritating to the skin, has a certain pollution to the tunnel working environment, and has corrosion hazards to metal equipment such as the working face support; the commonly used ordinary inhibitors have a relatively low inhibitory rate of about 50%. Summary of the Invention

[0003] The present invention aims to address the technical problems of conventional inorganic inhibitors, which suffer from low retardancy, severe corrosion to pipelines, and susceptibility to failure at high temperatures. To address these technical issues, the present invention provides a liquid polymer inhibitor for coal mines and a method for its preparation to meet this need in the art.

[0004] In one aspect, the present invention relates to a method for preparing a liquid polymer inhibitor for coal mines, comprising: copolymerizing an acrylate compound to obtain a hydrophobic acrylate polymer; The hydrophobic acrylate polymer is placed in a solution environment containing a hydrophilic polymer precursor, a cross-linking agent, a surfactant, an antioxidant and a solvent, and after the heating reaction is completed, the solution is cooled to room temperature to obtain the liquid polymer inhibitor.

[0005] Furthermore, in the preparation method of the liquid polymer inhibitor for coal mines provided by the present invention, the hydrophilic polymer precursor is an epoxy compound; The epoxy compound is selected from at least one of glycidyl methacrylate, tetrahydrofurfuryl methacrylate, and 3,4-epoxycyclohexyl methacrylate.

[0006] Furthermore, in the method for preparing the liquid polymer inhibitor for coal mines provided by the present invention, the acrylic acid ester compound is at least one selected from methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

[0007] Furthermore, in the preparation method of the liquid polymer inhibitor for coal mines provided by the present invention, the cross-linking agent is selected from at least one of borax, epichlorohydrin, and toluene diisocyanate.

[0008] Furthermore, in the preparation method of the liquid polymer inhibitor for coal mines provided by the present invention, the surfactant is selected from at least one of polyoxyethylene sorbitan fatty acid ester, sulfobetaine, and lecithin.

[0009] Furthermore, in the method for preparing the liquid polymer inhibitor for coal mines provided by the present invention, the antioxidant is a hindered phenol antioxidant.

[0010] Furthermore, in the method for preparing the liquid polymer inhibitor for coal mines provided by the present invention, the solvent is selected from at least one of methanol, ethanol, and butanol.

[0011] On the other hand, the present invention relates to a liquid polymer inhibitor for coal mines, which is prepared by the preparation method of the liquid polymer inhibitor for coal mines.

[0012] Furthermore, in the liquid polymer inhibitor for coal mines provided by the present invention, the raw materials are composed of the following components in parts by mass: 100-300 parts of the hydrophobic acrylate polymer; 120-200 parts of the hydrophilic polymer precursor; 5 to 10 parts of the cross-linking agent; 1 to 10 parts of the surfactant; 30-60 parts of the antioxidant; 20 to 80 parts of the solvent.

[0013] Furthermore, in the liquid polymer inhibitor for coal mines provided by the present invention, the inhibition rate of the liquid polymer inhibitor for coal mines is not less than 95%.

[0014] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects or advantages: The present invention utilizes an interpenetrating network of hydrophobic and hydrophilic polymers to create a liquid polymer inhibitor. This effectively addresses the technical challenges of conventional inorganic oxygen-blocking fire extinguishing agents, including low retardancy, susceptibility to high-temperature failure, corrosiveness to equipment and pipelines, short retardancy lifespan, volatility, high addition ratios, high transport volumes, significant skin irritation, environmental pollution to tunnels, and corrosion hazards to metal equipment such as working face supports. The resulting liquid polymer inhibitor for coal mines exhibits a high retardancy. While conventional calcium chloride and / or magnesium chloride have an retardancy of approximately 50%, the present invention achieves a retardancy of no less than 95%, maintains excellent retardancy at 180°C, and extends its retardancy lifespan by over 30 days compared to conventional inhibitors (calcium chloride and / or magnesium chloride). Furthermore, the present invention significantly reduces the addition ratio, transportation volume, and worker workload, as well as skin irritation, pollution to tunnels, and corrosion hazards to metal equipment such as working face supports, significantly enhancing coal mine safety. DETAILED DESCRIPTION

[0015] The technical solutions of the present invention are described below with reference to the following examples. However, the present invention is not limited to the following examples. The experimental methods and detection methods described in each example are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified. The percentages in the following examples are percentages by mass unless otherwise specified. The ratios in the following examples are ratios by mass unless otherwise specified.

[0016] Example 1 This example provides a preparation process of hydrophobic acrylate polymer A.

[0017] Take 1.6 mol of methyl methacrylate, 2.3 mol of ethyl methacrylate, 1.4 mol of butyl methacrylate, 0.2 mol of α-methylstyrene dimer, 0.5 mol of benzoyl peroxide and 20 mol of N-methylpyrrolidone, heat to 70°C with stirring and react for 5 hours, and then cool to room temperature to obtain a hydrophobic acrylate polymer with Mw=7362 and PDI=2.0.

[0018] Based on the hydrophobic acrylate polymer prepared in Example 1, the preparation of a liquid polymer inhibitor for coal mines was carried out as follows.

[0019] Example 2 This example provides a preparation process of hydrophobic acrylate polymer B.

[0020] 1.5 mol of methyl methacrylate, 1.5 mol of ethyl methacrylate, 2.0 mol of butyl methacrylate, 0.4 mol of dodecyl mercaptan, 0.5 mol of benzoyl peroxide and 15 mol of N-methylpyrrolidone were heated to 80°C with stirring for 6 hours, and then cooled to room temperature to obtain a hydrophobic acrylate polymer with Mw=9942 and PDI=1.8.

[0021] Based on the hydrophobic acrylate polymer prepared in Example 2, the preparation of a liquid polymer inhibitor for coal mines was carried out as follows.

[0022] Example 3 This example provides a preparation process of a liquid polymer inhibitor for coal mines.

[0023] The raw material composition of each test group is shown in the following table:

[0024] Under nitrogen protection, the above raw materials were added into a three-necked flask, heated to 70° C. with stirring, and reacted for 5 hours. The mixture was then cooled to room temperature to obtain a liquid polymer inhibitor for coal mines.

[0025] Example 4 This example provides the performance test results of the liquid polymer inhibitor for coal mines prepared in Example 3.

[0026] The selected coal sample is processed into coal powder and placed in the adsorption cylinder of the coal adsorption oxygen detection device. The remaining space in the adsorption cylinder is filled with air to simulate the air environment during coal spontaneous combustion. A gas outlet and a pressure gauge are provided on the adsorption cylinder. The gas outlet is connected to a gas chromatograph. According to the changes in oxygen concentration and pressure in the adsorption cylinder before and after adsorption, the adsorption amount of oxygen in the air by the coal under normal temperature and pressure conditions is measured. The liquid polymer retarder provided in Example 2 is mixed with water, and the concentration of the liquid polymer retarder is 20% to obtain a final product. The final product is evenly sprayed on the surface of the coal sample in the coal sample, with a spraying pressure of 2.7MPa and a single spraying thickness of 4mm. The cycle spraying is 3 times, and the spraying interval is 2h. The first spraying needs to ensure that the fire-proof extinguishing material covers the wrapped coal sample surface. After spraying is completed, it is left to stand for 12h and recorded as the retarded coal sample. Take 50g of each of the raw coal sample and the inhibitory coal sample and place them in a heat treatment tank. Pass compressed air (oxygen content is 21%) at a rate of 80mL / min. Twelve heat treatment tanks are heated at a rate of 0.8℃ / min. At 100℃ and 180℃, gas samples are collected from the heat treatment tanks to measure the volume fraction (%) of CO gas. The inhibitory rate refers to the ratio of the difference in the CO gas volume fraction between the raw coal sample and the inhibitory coal sample to the CO gas volume fraction of the inhibitory coal sample under the same conditions. It is calculated as follows: E=(AB)×100% / A; Where: E is the inhibition rate, %; A is the volume fraction of CO gas in the original coal sample, %; and B is the volume fraction of CO gas in the inhibition coal sample, %.

[0027] The test results are shown in the following table.

[0028]

[0029] Because the networks that comprise an interpenetrating polymer network (IPN) are formed through the entanglement of molecular chains, they can leverage the adsorption capacity of each component network, producing a synergistic effect. Currently, the hydrophobicity and hydrophilicity of the polymer networks comprising IPNs reported in the literature are generally similar or identical, and there are few reports on IPNs composed of both hydrophobic and hydrophilic cross-linked polymers. The present invention aims to utilize this principle to produce a liquid polymer inhibitor for coal mines. The elastic recovery force generated by the entanglement of the molecular chains that comprise the IPN networks enhances the adhesion and barrier properties of the IPN polymer on the coal surface, thereby improving its barrier efficiency and longevity at high temperatures. The test results above demonstrate that the liquid polymer inhibitor for coal mines produced by the present invention exhibits a high barrier efficiency (compared to approximately 50% for conventional calcium chloride and / or magnesium chloride) and maintains a good barrier effect at 180°C. Inhibitors using only hydrophilic polymers exhibit poor barrier efficiency and are prone to failure at high temperatures; and inhibitors using only hydrophobic polymers exhibit no barrier effect.

[0030] Example 5 This example provides an application in a coal mine project.

[0031] The liquid polymer inhibitor #3 prepared in Example 3 has a boiling point range of less than 64.8°C during dissolution or deliquescence, is non-self-igniting, has an inhibitory rate of more than 95%, is resistant to high temperatures, and has a mixing ratio of 1 to 30 times. 2.0% to 5.0% of this product is added for fire prevention, and 6.0% to 10.0% of this product is added for fire extinguishing.

[0032] Parameter calculation of recommended dosage, spraying amount on the working surface at one time: The spraying amount of each working surface can be calculated as follows: V1=K1·K2·L·B·h1·A1 / g Where: V1 is the amount of floating coal sprayed each time calculated by volume, kg; K1 - the dosage coefficient of the liquid in the part prone to spontaneous combustion, generally 1.2; K2——bulk density of loose coal in goaf, (0.8-1.0)t / m 3 , take 1.0; L——working surface length, (50-80)m, take 80; B——spraying width at one time, 0.8m; h1——floating coal thickness on the bottom plate, 0.05m; A1——the original floating (floating coal) liquid absorption capacity is 5kg / t; g——Inhibitor solution density 1.05t / m 2 .

[0033] Substitute into the formula: V1=1.2×1.0×80×0.8×0.05×5 / 1.05=18.3kg; The working surface should be sprayed once daily during maintenance, with the spraying amount not less than 18.3 kg each time.

[0034] (1) Drilling and spraying between and behind the working face frames: The equipment used includes mining-grade chemical pumps, pneumatic chemical pumps, grouting pumps, diaphragm pumps, screw pumps, plunger pumps, and mud pumps; or a surface grouting system can be used to mix and inject yellow mud slurry. As the working face advances, inter-frame and post-frame spraying, drilling, and pre-buried pipelines are used to cover the floating coal in the goaf with chemical slurry over a large area. The application process can be based on the mine's spraying of each frame or interval pressure injection spraying. The material remains in a liquid state during preparation and use, without any heat generation process. It has a large heat absorption capacity, good cooling performance, and high fire prevention and fire extinguishing efficiency.

[0035] (2) Opening the cutting hole and stopping the mining line: The injection equipment can include mining-grade chemical pumps, pneumatic chemical pumps, grouting pumps, diaphragm pumps, screw pumps, plunger pumps, and mud pumps. Alternatively, yellow mud slurry can be mixed with a surface grouting system to seal the corresponding locations of the cut holes or stop-line. The required injection volume can be adjusted according to the actual conditions of each mine. According to the mine's experience, when the underground working face is 30 meters away from the stop-line, high-efficiency chemical inhibitors are used to prevent the floating coal at the working face's air supply and return terminals and in the goaf as the working face advances. This prevents the floating coal from spontaneously combusting and oxidizing, thus providing safety for the working face withdrawal.

[0036] (3) Spraying floating coal in upper and lower corners: Inject oxygen-blocking fire extinguishing agent material into the upper and lower corners and the floating coal behind the rack.

[0037] In summary, during the project trial, the liquid polymer inhibitor for coal mines provided by the present invention has an inhibition rate increased by more than 30% compared with traditional inhibitors, and the inhibitor of the present invention has a long inhibition life, which is extended by more than 30 days compared with traditional inhibitors (calcium chloride and / or magnesium chloride).

[0038] As described above, the basic principles, main features and advantages of the present invention are well described. The above embodiments and descriptions are merely descriptions of preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit and scope of the present invention should fall within the scope of protection determined by the present invention.

Claims

1. A method for preparing a liquid polymer inhibitor for coal mines, characterized in that: include: The acrylate compound is copolymerized to obtain a hydrophobic acrylate polymer; The hydrophobic acrylate polymer is placed in a solution environment containing a hydrophilic polymer precursor, a cross-linking agent, a surfactant, an antioxidant and a solvent, and after the heating reaction is completed, the solution is cooled to room temperature to obtain the liquid polymer inhibitor.

2. The method for preparing a liquid polymer inhibitor for coal mines according to claim 1, characterized in that: The hydrophilic polymer precursor is an epoxy compound; The epoxy compound is selected from at least one of glycidyl methacrylate, tetrahydrofurfuryl methacrylate, and 3,4-epoxycyclohexyl methacrylate.

3. The method for preparing a liquid polymer inhibitor for coal mines according to claim 1, characterized in that: The acrylic acid ester compound is selected from at least one of methyl methacrylate, ethyl methacrylate and butyl methacrylate.

4. The method for preparing a liquid polymer inhibitor for coal mines according to claim 1, characterized in that: The cross-linking agent is selected from at least one of borax, epichlorohydrin and toluene diisocyanate.

5. The method for preparing a liquid polymer inhibitor for coal mines according to claim 1, characterized in that: The surfactant is selected from at least one of polyoxyethylene sorbitan fatty acid ester, sulfobetaine, and lecithin.

6. The method for preparing a liquid polymer inhibitor for coal mines according to claim 1, characterized in that: The antioxidant is a hindered phenol antioxidant.

7. The method for preparing a liquid polymer inhibitor for coal mines according to claim 1, characterized in that: The solvent is selected from at least one of methanol, ethanol and butanol.

8. A liquid polymer inhibitor for coal mines, characterized in that: The liquid polymer inhibitor for coal mines is prepared by the preparation method of any one of claims 1 to 7.

9. The liquid polymer inhibitor for coal mines according to claim 8, characterized in that: The raw materials are composed of the following components in parts by mass: 100-300 parts of the hydrophobic acrylate polymer; 120-200 parts of the hydrophilic polymer precursor; 5 to 10 parts of the cross-linking agent; 1 to 10 parts of the surfactant; 30-60 parts of the antioxidant; 20 to 80 parts of the solvent.

10. The liquid polymer inhibitor for coal mines according to claim 8, characterized in that: The liquid polymer inhibitor for coal mines has an inhibition rate of not less than 95%.

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