Macromolecular environment-friendly flame retardant and preparation method thereof

Abstract

The invention discloses a high-molecular environment-friendly flame retardant and a preparation method thereof, and relates to the technical field of high-molecular environment-friendly flame retardants, and the preparation method comprises the following steps: obtaining vinyl acetate, methyl methacrylate, butyl acrylate, lauryl sodium sulfate and water as raw materials; vinyl acetate and methyl methacrylate are uniformly mixed; dissolving butyl acrylate in water, and uniformly mixing the butyl acrylate and the water; uniformly mixing and fusing the mixed reagent and water; adding lauryl sodium sulfate into the mixed solution, uniformly mixing and fusing; and stirring for 1 hour until all the reagents and the solution are uniformly mixed, thereby synthesizing the flame retardant. A covering layer is formed on the surface of coal through the flame retardant, and coal spontaneous combustion is inhibited. The problem that a traditional coal pile spontaneous combustion prevention measure is poor in effect is effectively solved, the flame retardant can agglomerate coal particles and isolate air, and coal pile spontaneous combustion is effectively restrained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular environmentally friendly flame retardant, in particular to a high molecular environmentally friendly flame retardant and a preparation method thereof. BACKGROUND

[0002] In recent years, the amount of low-rank coal used by coal-fired power plants in China is rapidly increasing. The main reason is that the coal produced by newly developed major coalfields such as the Ordos Basin coalfield (including the Shengli-Dongsheng coalfield in the Shenhua mining area), the Zhundong coalfield in Xinjiang, and others is high-volatile bituminous coal and lignite. In addition, power plants in the eastern coastal areas, including Guangdong Province, use a large amount of imported cheap coal, including Indonesian coal, Philippine coal, etc. These coals are mainly low-rank sub-bituminous coal and lignite. During the actual production, transportation, storage, and utilization of coal, spontaneous combustion often occurs, such as in open-air coal piles in coal mines and power plants, and in coal piles stored in transport boxes during ocean shipping and railway transportation. According to statistics, about 56% of state-owned coal mines in China are at risk of coal spontaneous combustion every year, in addition to coal spontaneous combustion during transportation, the country suffers huge economic and resource losses every year, and coal spontaneous combustion also causes serious environmental pollution.

[0003] Spontaneous combustion not only causes the calorific value of coal to decrease, but also increases the ash content of coal, reduces the carbon and hydrogen content, and decreases the crushing strength. Coal spontaneous combustion not only causes huge economic losses to power plants, but also seriously pollutes the surrounding environment. Therefore, preventing coal spontaneous combustion is one of the main effective measures for power plants to reduce power generation costs and achieve energy saving and emission reduction.

[0004] Currently, the main method for treating coal spontaneous combustion is physical method, such as water spraying for flame retardation, burning old coal to store new coal (the longer the coal is stored, the more serious the low-temperature oxidation, therefore, by burning old coal to store new coal, the storage time of coal is shortened, which is a measure to reduce low-temperature oxidation), layered compaction and stacking (layered compaction and stacking is very effective for preventing coal pile spontaneous combustion, especially for coal susceptible to oxidation, layered compaction must be done. Because the surface of the compacted coal pile forms a hard shell, the particle gap in the coal pile is small, which can effectively prevent air and rainwater from penetrating, thereby destroying the conditions for coal oxidation and temperature rise and causing spontaneous combustion, and can effectively prevent coal pile spontaneous combustion. However, this method requires the cooperation of many mechanical equipment, is time-consuming and labor-intensive, and has high cost.

[0005] Therefore, a high molecular environmentally friendly flame retardant is developed to solve the problems of coal spontaneous combustion and environmental pollution, achieve the goals of energy saving and environmental protection, and have huge economic benefits and social benefits. SUMMARY

[0006] The technical problem solved by the present application is to provide a high-molecular environmentally-friendly flame retardant and a preparation method thereof to effectively solve the problem of poor effect of traditional coal pile anti-spontaneous combustion measures.

[0007] The present application solves the above technical problems by using the following technical solutions: A high-molecular environmentally-friendly flame retardant, which is composed of the following components in parts by mass: Vinyl acetate: 10-12 parts; Methyl methacrylate: 1-3 parts; Butyl acrylate: 1-2 parts; Sodium dodecyl sulfate 3-8 parts; Water 75-85 parts.

[0008] A preparation method of a high-molecular environmentally-friendly flame retardant, specifically comprising the following steps: Step (1) uniformly mix vinyl acetate and methyl methacrylate; Step (2) dissolve butyl acrylate in water and mix them uniformly; Step (3) mix and fuse the mixed reagents and water; Step (4) add sodium dodecyl sulfate to the above mixture, mix and fuse; stir for 1 h until all reagents and solutions are mixed uniformly, and the flame retardant is synthesized.

[0009] Further, a preparation method of a high-molecular environmentally-friendly flame retardant mainly includes: Obtain vinyl acetate, methyl methacrylate, butyl acrylate, sodium dodecyl sulfate and water as raw materials; mix the raw materials in a predetermined ratio and perform emulsion polymerization to obtain a flame retardant; and form a covering layer on the surface of coal by the flame retardant to inhibit spontaneous combustion of coal.

[0010] Further, the mixing of the raw materials in a predetermined ratio and the emulsion polymerization include: uniformly mixing vinyl acetate and methyl methacrylate to obtain a first mixture; dissolving butyl acrylate in water to obtain a second mixture; fusing the first mixture and the second mixture to obtain a third mixture; adding sodium dodecyl sulfate to the third mixture and stirring until uniform to complete the emulsion polymerization and obtain the flame retardant.

[0011] Further, the obtaining of vinyl acetate, methyl methacrylate, butyl acrylate, sodium dodecyl sulfate and water as raw materials includes: obtaining 10-12 parts of vinyl acetate, 1-3 parts of methyl methacrylate, 1-2 parts of butyl acrylate, 3-8 parts of sodium dodecyl sulfate and 75-85 parts of water as raw materials according to the mass percentage.

[0012] Further, the forming of the covering layer on the surface of the coal by the flame retardant comprises: spraying the flame retardant on the surface of the coal; agglomerating the coal particles by the adhesion of the flame retardant to form a solidified covering layer; and isolating the coal from the air by the solidified covering layer to inhibit the oxidation of the coal.

[0013] Further, the adding of the sodium dodecyl sulfate into the third mixed solution and stirring until uniform comprises: adding the sodium dodecyl sulfate into the third mixed solution; stirring the third mixed solution with the added sodium dodecyl sulfate by a stirring device for 1 hour to obtain a uniform emulsion polymerization product; and determining the flame retardant by the emulsion polymerization product.

[0014] Further, the isolating of the coal from the air by the solidified covering layer comprises: reducing the contact area between the surface of the coal and oxygen by the solidified covering layer; reducing the gap between the coal particles by the solidified covering layer to limit the air penetration; and judging the reduction degree of the spontaneous combustion risk of the coal according to the covering effect of the solidified covering layer.

[0015] Further, the obtaining of the raw materials according to the mass percentage, that is, 10-12 parts of vinyl acetate, 1-3 parts of methyl methacrylate, 1-2 parts of butyl acrylate, 3-8 parts of sodium dodecyl sulfate and 75-85 parts of water, comprises: determining the mass percentage of each raw material; measuring the vinyl acetate, the methyl methacrylate, the butyl acrylate, the sodium dodecyl sulfate and the water according to the mass percentage; and determining the raw material combination for the emulsion polymerization by the measured raw materials.

[0016] The technical scheme provided by the embodiment of the present application can include the following beneficial effects: (1) The present application discloses a preparation method of a high-molecular environmentally-friendly flame retardant and its application in coal pile spontaneous combustion prevention, which prepares a high-molecular environmentally-friendly flame retardant with adhesion and stability by an emulsion polymerization method, and uniformly sprays the flame retardant on the surface of the coal pile to form an isolation film layer; the method solves the problem of poor effect of traditional coal pile spontaneous combustion prevention measures, and the flame retardant can agglomerate coal particles and isolate air to effectively inhibit the spontaneous combustion of the coal pile. The present application also includes detection and supplementary spraying of the coverage integrity of the isolation film layer, and regular inspection and maintenance to ensure long-term spontaneous combustion prevention effect; the method is simple and convenient to operate, environmentally-friendly and safe, can significantly reduce the risk of coal pile spontaneous combustion, improve the safety of coal storage and transportation, and has good practical value. (2) The present application forms a covering layer on the surface of the coal pile after spraying, agglomerates dispersed coal particles together by the adhesion of the flame retardant to form a complete "film" covering on the surface of the coal pile, so as to isolate the coal pile from the air. (3) The present application is a ternary copolymer flame retardant prepared by emulsion polymerization method with vinyl acetate as the main monomer, methyl methacrylate as the hard monomer, butyl acrylate as the soft monomer, and sodium dodecyl sulfate as the composite emulsifier, and water as the dispersion medium without using organic solvents, and is applied to inhibit coal spontaneous combustion. The prepared flame retardant has good stability, strong adhesion, is non-toxic and harmless, and is environment-friendly. (4) The present application has low cost, simple preparation process, and can effectively inhibit low-rank coal spontaneous combustion. Compared with the water spraying flame retardant method, the present application has good flame retardant effect, and will not reduce the received base low calorific value of coal, affect pricing, and cause trade disputes. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The present application is a kind of high molecular environmental protection flame retardant preparation method flow chart. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be described in detail below with reference to the drawings and specific examples.

[0019] A kind of high molecular environmental protection flame retardant, its composition is composed of: Vinyl acetate: 10-12 parts; Methyl methacrylate: 1-3 parts; Butyl acrylate: 1-2 parts; Sodium dodecyl sulfate 3-8 parts; Water 75-85 parts.

[0020] A kind of preparation method of high molecular environmental protection flame retardant, as shown in Figure 1 Specifically includes the following steps: Step (1) mix vinyl acetate and methyl methacrylate uniformly; Step (2) dissolve butyl acrylate in water, and mix them uniformly; Step (3) mix the mixed reagent and water uniformly and fuse; Step (4) add sodium dodecyl sulfate to the above mixture, mix and fuse; stir for 1h until all reagents and solutions are mixed uniformly, that is, the flame retardant is synthesized.

[0021] The preparation method of the high molecular environmental protection flame retardant of the present application can specifically include: S101, obtain raw material components for preparing high molecular environmental protection flame retardant, the raw material components include vinyl acetate, methyl methacrylate, butyl acrylate, sodium dodecyl sulfate and water.

[0022] The initial components for preparing the high-molecular environmentally friendly flame retardant are obtained from the raw material reserves, which include vinyl acetate, methyl methacrylate and butyl acrylate. These monomers are mixed in a predetermined ratio to form a uniform monomer mixture. Water is added as a dispersion medium in the monomer mixture, and the mixture is thoroughly stirred to form a preliminary emulsion, ensuring that the monomers are uniformly dispersed in water, providing a stable liquid environment for the subsequent emulsion reaction. For the preliminary emulsion, sodium dodecyl sulfate is added as a composite emulsifier, and the emulsifier is thoroughly mixed with the emulsion by continuous stirring to form a stable emulsion system, laying the foundation for the subsequent polymerization reaction. In the stable emulsion system, the flame retardant is prepared by emulsion polymerization, and the reaction conditions are controlled to ensure chemical combination between the raw material components, forming a high-molecular environmentally friendly flame retardant material with adhesion and stability.

[0023] For example, in the process of preparing the high-molecular environmentally friendly flame retardant, obtaining the initial components is the key first step.

[0024] Specifically, vinyl acetate, methyl methacrylate and butyl acrylate are selected as monomers from the raw material reserves, which provide flexibility, hardness and adhesion, respectively. Uniformity must be ensured during mixing to avoid uneven distribution of components in subsequent reactions. For example, in the laboratory, the three monomers can be placed in a stirred container to form a transparent monomer mixture by mechanical stirring. This uniform mixture provides a stable chemical basis for the subsequent emulsion reaction, helping to ensure the uniformity of the polymer chain structure.

[0025] In one embodiment, after the monomer mixture is prepared, water is added as a dispersion medium to form a preliminary emulsion. As an environmentally friendly dispersion medium, water can effectively reduce the use of organic solvents while providing a liquid environment for the emulsion reaction.

[0026] For example, the monomer mixture can be slowly added to a reaction kettle containing an appropriate amount of water, and the monomers are dispersed into small droplets in the water by high-speed stirring. The formation of this preliminary emulsion ensures uniform distribution of monomer particles, laying the foundation for the addition of emulsifiers and the stability of the reaction system, which helps to improve the film-forming properties of the flame retardant.

[0027] Preferably, after the preliminary emulsion is formed, sodium dodecyl sulfate is added as a composite emulsifier to further improve the stability of the system. Sodium dodecyl sulfate can make the monomer droplets more stably dispersed in water by reducing the surface tension of the droplets.

[0028] For example, under stirring conditions, the sodium dodecyl sulfate solution is gradually added to the preliminary emulsion, and continuous stirring is performed until a uniform emulsion system is formed. This stable emulsion system can effectively prevent droplet coalescence, providing a reliable reaction environment for the subsequent emulsion polymerization reaction, thereby ensuring uniform distribution of the molecular weight of the flame retardant.

[0029] In one possible implementation, the stable emulsification reaction is completed by emulsion polymerization in the emulsification system. The emulsion polymerization method causes the monomers to polymerize within the emulsion droplets by controlling the reaction conditions, such as the initiator concentration and temperature, to form the terpolymer.

[0030] For example, the initiator can be added to the emulsification system under the protection of nitrogen, and heated to an appropriate temperature to promote the copolymerization of vinyl acetate, methyl methacrylate, and butyl acrylate. The flame retardant prepared by this method has excellent adhesion and stability, and can form a dense covering film on the surface of the coal pile to effectively isolate air and achieve the purpose of environmental protection and flame retardation.

[0031] S102, according to the preset mass ratio, the vinyl acetate and the methyl methacrylate are preliminarily mixed to obtain a first mixed liquid, and the first mixed liquid is uniformly mixed by stirring.

[0032] The vinyl acetate and the methyl methacrylate are preliminarily mixed according to the preset mass ratio to form a first mixed liquid, and the two monomers are uniformly mixed by continuous stirring during the mixing process to obtain a uniform first mixed liquid. A predetermined amount of butyl acrylate is added as a soft monomer to the first mixed liquid, and the three monomers are fully dispersed in the liquid by mixing with a stirring device to form a second mixed liquid. Sodium dodecyl sulfate is added as a composite emulsifier to the second mixed liquid, water is used as a dispersion medium, and the reaction is carried out by emulsion polymerization to ensure uniform distribution of the components during the reaction, generating a preliminary copolymer solution. Continue to stir the preliminary copolymer solution for a period of time to ensure that all components are fully mixed and reach a stable state, and finally form a flame retardant for inhibiting spontaneous combustion of coal.

[0033] For example, in the actual preparation process, the vinyl acetate and the methyl methacrylate are first preliminarily mixed according to the preset ratio, and the key to this process is to ensure uniform mixing of the two monomers. Assuming that in a laboratory environment, a reaction container with a stirring device is used, and the two monomers are slowly added to it and mixed at a constant speed by the stirring device, which can effectively avoid local concentration unevenness. This uniform mixing lays the foundation for the addition of subsequent monomers and helps to improve the stability of the final product.

[0034] Specifically, after the initial mixing is completed, butyl acrylate is added as a soft monomer for further mixing. The addition of butyl acrylate can adjust the flexibility of the final product, making it easier to form a covering layer when applied. Assuming that in industrial production, using a stirring device with temperature control function, butyl acrylate is gradually added to the formed mixture, while controlling the stirring speed and time, ensuring that the three monomers are fully dispersed. This dispersion effect directly affects the uniformity of the subsequent reaction, which is crucial for forming high-quality flame retardants.

[0035] For example, sodium dodecyl sulfate is added as a complex emulsifier in the mixture, and water is used as the dispersion medium for emulsion polymerization. Emulsion polymerization is a polymerization method carried out in an aqueous phase, where monomers are dispersed into tiny droplets through the action of emulsifiers, thus achieving uniform reaction. Assuming that in the production scenario, after dissolving the emulsifier in water, it is slowly added to the mixture and subjected to high-shear emulsification treatment through a specific device, ensuring uniformity of monomer droplet size. This approach can significantly improve reaction efficiency and ensure that the generated copolymer solution has good stability, providing a guarantee for subsequent applications.

[0036] Specifically, the generated copolymer solution is continuously stirred for a period of time to ensure that all components are fully integrated and reach a stable state. This process can be seen as a consolidation and optimization of the previous reaction. Assuming that in actual operation, using a stirring device with a timing function, a reasonable stirring time is set to ensure that there is no obvious stratification or precipitation in the solution. This process of full integration can enhance the adhesion properties of the flame retardant, allowing it to form a solid covering layer on the surface of coal, effectively isolating air and achieving the purpose of suppressing spontaneous combustion. Through the close connection of each link, each step provides necessary support for the final formation of high-quality flame retardants, significantly improving the practical value of the product.

[0037] S103, using a dissolution method, butyl acrylate is added to the water, and after stirring evenly, a second mixture is obtained, which is used as a dispersion medium for subsequent reactions.

[0038] The butyl acrylate is slowly added to the previously prepared water, and stirring is continued during the addition to ensure uniform dispersion of the butyl acrylate in the water, forming a preliminary mixture. For the preliminary mixture, stirring is continued for a period of time to make the mixture of butyl acrylate and water more uniform, obtaining a second mixture, ensuring that it has good stability as a dispersion medium for subsequent reactions. The second mixture is placed in a reaction vessel to maintain a suitable reaction environment, providing a stable dispersion medium basis for the subsequent addition of other monomers and emulsifiers. Other reaction raw materials, such as vinyl acetate and methyl methacrylate, are gradually added to the second mixture, taking advantage of the dispersion medium properties of the second mixture to ensure uniform mixing of each raw material, laying the foundation for subsequent emulsion polymerization reactions, and thus achieving the goal of preparing a flame retardant for inhibiting coal spontaneous combustion.

[0039] For example, in the process of preparing a flame retardant, butyl acrylate is slowly added to the previously prepared water, and stirring is continued to ensure uniform dispersion. Assuming that in a laboratory environment, a container with a stirring device is used, a certain amount of pure water is poured in first, and then butyl acrylate is added at a slow rate, and the stirring device is kept at medium speed. The purpose of this is to allow butyl acrylate to be dispersed in the water in the form of fine droplets, avoiding local aggregation, thereby forming a preliminary mixture. This uniform dispersion is crucial for the smooth progress of subsequent reactions, as it directly affects the stability of the dispersion medium.

[0040] For example, further processing of the preliminary mixture requires continued stirring for a period of time to improve uniformity. Assuming that in the above laboratory scenario, the stirring device continues to work for a period of time to ensure that the mixture of butyl acrylate and water reaches a stable state, obtaining a second mixture. The purpose of this process is to strengthen the properties of the dispersion medium, allowing it to better carry the subsequent addition of raw materials. If this step is not done well, the subsequent raw materials may not be uniformly distributed, affecting the performance of the final flame retardant. Through such processing, a reliable foundation can be provided for subsequent reactions.

[0041] For example, placing the second mixture in a reaction vessel and maintaining a suitable reaction environment is an important step to pave the way for subsequent steps. Assuming that in the experiment, a corrosion-resistant and well-sealed reaction vessel is chosen, the second mixture is poured into it, and the temperature and pressure inside the container are controlled by external equipment. The benefit of this is to provide a stable environment for the subsequent addition of other monomers and emulsifiers, ensuring controllable reaction process, thereby helping to generate flame retardants with consistent performance.

[0042] For example, in the second mixture, gradually add other raw materials, such as vinyl acetate and methyl methacrylate, use its dispersion medium characteristics to ensure uniform mixing of raw materials, this process has a direct impact on the quality of the final product. It is envisaged that in the experimental operation, first add a small amount of vinyl acetate in multiple ways, observe the state of the mixture while adding, then add methyl methacrylate, continue to stir to avoid stratification. The benefit of doing so is to make full use of the dispersion capacity of the second mixture, so that various raw materials are fully integrated, creating favorable conditions for subsequent emulsion polymerization, ultimately helping to prepare a flame retardant that can effectively inhibit the spontaneous combustion of coal. The effect of such uniform mixing can significantly improve the coverage of the flame retardant on the surface of the coal pile, enhancing the protective effect.

[0043] S104, the first mixture is mixed with the second mixture, and the two mixtures are fully mixed by continuous stirring to obtain a third mixture, which is a basic solution for emulsion polymerization.

[0044] The first mixture and the second mixture are preliminarily mixed according to a predetermined ratio to form an initial mixture, ensuring that the two liquids are fully contacted in the container, laying a foundation for subsequent fusion processing. For the initial mixture, a continuous stirring method is used to mix the initial mixture by a stirring device at a constant speed, so that the components in the initial mixture are uniformly distributed to obtain a transition mixture. An appropriate amount of emulsifying aid, such as sodium dodecyl sulfate, is added to the transition mixture to enhance the fusion effect between the liquids, and the stirring is continued to ensure that the emulsifying aid is fully combined with the transition mixture to form a stable third mixture. The third mixture is observed to determine whether the stratification meets the requirements of the basic solution for emulsion polymerization. If the stratification does not meet the predetermined standard, the stirring is adjusted again until the third mixture meets the uniformity and stability of the basic solution for emulsion polymerization.

[0045] Specifically, when the first mixture and the second mixture are preliminarily mixed according to a predetermined ratio, the two liquids can be slowly poured into a glass container in a laboratory environment to ensure that they do not produce local non-uniformity when they come into contact due to too fast mixing. This method helps the two liquids to form a relatively uniform initial mixture in the initial stage, providing good foundation conditions for subsequent processing. Such operation can effectively avoid stratification or local high concentration of liquids, thereby laying a foundation for further fusion.

[0046] In one embodiment, for the initial mixture, a continuous stirring method can be used with an electric stirring device by setting a stable speed for the stirring paddle to rotate at a constant speed in the container, so that the various components in the initial mixture are fully contacted and dispersed.

[0047] For example, when dealing with a mixture similar to emulsion polymerization, the stirring process can last for a certain period of time to ensure that the tiny particles or droplets inside the liquid are evenly distributed, resulting in a transitional mixture. This evenly distributed state helps the subsequent addition of other additives to be more quickly integrated into the overall liquid, improving mixing efficiency.

[0048] Specifically, when adding emulsifying aids such as sodium dodecyl sulfate to the transitional mixture, the aid can be gradually added to the liquid in small quantities over multiple times while maintaining the stirring state.

[0049] For example, in an experimental scenario, after adding a small amount of aid each time, observe whether there are obvious changes in bubbles or particles on the surface of the liquid to ensure that the aid is fully combined with the transitional mixture. This approach can enhance the integration effect between liquids, form a stable third mixture, and avoid the phenomenon of local aggregation caused by the one-time addition of too much aid, ensuring the stability of the emulsion system.

[0050] In one embodiment, when observing the third mixture, the mixture can be placed in a transparent container and observed for a period of time to see if there are obvious stratification or precipitation phenomena. If stratification is found to not meet the requirements of the emulsion polymerization base solution, the stirring device needs to be started again for adjustment.

[0051] For example, in some preparation process of emulsion polymerization, if the upper layer of the liquid appears thin, while the lower layer is relatively thick, the overall liquid can be re-adjusted to an even state by stirring again. This repeated adjustment process can ensure that the third mixture meets the needs of subsequent polymerization reactions, providing a guarantee for the final preparation of a stable emulsion polymerization base solution. Through such meticulous operation, the quality and applicability of the mixture can be significantly improved.

[0052] S105、For the third mixture, add the sodium dodecyl sulfate as an emulsifying agent, and through stirring and integration processing, all components are evenly dispersed to obtain a pre-reaction mixture, which is a precursor for the synthesis of a flame retardant.

[0053] For the third mixture, sodium dodecyl sulfate is added as an emulsifier. Through stirring and blending, the components are uniformly dispersed in the liquid, forming a preliminary mixed liquid, ensuring that the monomers and additives are in sufficient contact in the water medium, laying the foundation for subsequent reactions, and obtaining an initial dispersion. For the initial dispersion, continuous stirring is used to further promote the interaction between the components, allowing the emulsifier and monomer molecules to form stable micro-droplet structures, ensuring uniform distribution of substances before the reaction, and obtaining a pre-reaction mixture. For the pre-reaction mixture, the stirring conditions are adjusted to maintain the stability of the liquid, avoiding stratification or sedimentation, while providing a uniform precursor environment for subsequent emulsion polymerization reactions, ensuring the effective combination of components during the synthesis of flame retardants. For the pre-reaction mixture as a precursor for the synthesis of flame retardants, the uniformity is maintained by controlling the environmental conditions, providing a guarantee for the formation of stable ternary copolymer structures in subsequent polymerization reactions, and thus achieving the goal of synthesizing flame retardants.

[0054] Specifically, the process of adding sodium dodecyl sulfate as an emulsifier to the third mixture can be understood as a key step in uniformly dispersing the components in the liquid through stirring and blending. Sodium dodecyl sulfate, as a surfactant, can reduce the interfacial tension between the components in the liquid, thereby helping the monomers and additives form a uniform dispersion state in the water medium. For example.

[0055] In one possible implementation, the third mixture is placed in a stirring device, and after adding an appropriate amount of sodium dodecyl sulfate, the liquid is gradually brought to a uniform state through moderate stirring. This approach helps ensure that the monomers can fully contact each other in subsequent reactions, avoiding incomplete reactions caused by uneven local concentrations, thereby laying the foundation for the synthesis of flame retardants.

[0056] Next, the initial dispersion is further continuously stirred to promote the interaction between the components, with the goal of allowing the emulsifier and monomer molecules to form stable micro-droplet structures.

[0057] For example, in a laboratory environment, it can be observed that after continuous stirring, a fine milky appearance forms on the surface of the liquid, indicating that the emulsifier has encapsulated the monomer molecules into droplets. This droplet structure effectively prevents the monomers from aggregating or stratifying before the reaction, ensuring the uniformity of the pre-reaction mixture and providing stable basic conditions for subsequent polymerization reactions. This uniformity is crucial for the performance of the final flame retardant.

[0058] Furthermore, the step of adjusting the stirring conditions for the pre-reaction mixture to maintain stability is crucial in avoiding stratification or sedimentation of the liquid.

[0059] For example, in actual operation, if the liquid is found to have slight signs of stratification after standing, the uniform state can be restored by adjusting the stirring speed or increasing the stirring time. This approach can provide a stable precursor environment for the emulsion polymerization reaction, ensuring that the components are effectively combined during the reaction, thereby improving the adhesion and stability of the flame retardant.

[0060] Finally, for the environmental condition control of the reaction-premixed liquid as the flame retardant synthesis precursor, the purpose is to maintain the uniformity of the liquid to support the subsequent polymerization reaction to form a stable terpolymer structure. For example.

[0061] In one embodiment, the reaction-premixed liquid can be kept stable under certain conditions by controlling the temperature and humidity of the stirring equipment. This control can effectively avoid external factors from interfering, providing a guarantee for the formation of a uniform polymer structure in the subsequent reaction, ultimately helping to synthesize a flame retardant with excellent performance. This approach can significantly improve the effectiveness of the flame retardant in actual application.

[0062] S106, performing a polymerization reaction on the reaction-premixed liquid by an emulsion polymerization method, controlling the reaction time and stirring speed, to obtain a high-molecular environmentally friendly flame retardant, the high-molecular environmentally friendly flame retardant having adhesion and stability.

[0063] Vinyl acetate is used as the main monomer, combined with methyl methacrylate and butyl acrylate as auxiliary monomers, mixed in a predetermined ratio to form an initial mixed liquid, and sodium dodecyl sulfate is added as an emulsifier, with water as a dispersion medium to ensure uniform dispersion of the initial mixed liquid in an emulsified state. For the initial mixed liquid, a polymerization reaction is performed by an emulsion polymerization method, controlling the stirring rate and reaction time in the reaction environment, so that the monomer molecules gradually polymerize to form a high-molecular chain structure, obtaining a preliminary polymerization liquid. The preliminary polymerization liquid is further stirred to ensure the stability of the high-molecular chain structure and promote the interaction between the emulsifier and the polymer, forming a stable emulsion liquid with adhesion properties. The final high-molecular environmentally friendly flame retardant is obtained from the stable emulsion liquid, ensuring that it has strong adhesion and stability, and is used to form a covering layer on the surface of coal to isolate air and inhibit oxidation.

[0064] For example, in the actual preparation of polymeric environmentally friendly flame retardants, vinyl acetate is first used as the main monomer, mixed with methyl methacrylate and butyl acrylate in a certain proportion. The key to this step is ensuring a balanced ratio between the monomers to form a polymer structure with good adhesion. Assuming that in a laboratory environment, a higher proportion of vinyl acetate can enhance the flexibility of the final product, while methyl methacrylate helps to improve hardness. Adding sodium dodecyl sulfate as an emulsifier allows the mixture to form a stable emulsion in water, laying the foundation for subsequent polymerization reactions. This emulsion helps the monomer molecules distribute evenly, thereby improving reaction efficiency.

[0065] For example, emulsion polymerization is a core step in polymerization reactions. This method avoids the use of organic solvents by polymerizing monomers in an aqueous medium, making it more environmentally friendly. During the reaction, controlling the stirring rate and reaction time is crucial. If the stirring rate is too slow, it may lead to uneven monomer distribution, affecting the formation of polymer chains; while proper stirring allows monomer molecules to fully contact and gradually polymerize into a polymer chain structure. This process directly determines the stability of the final product, ensuring the formation of the subsequent capping layer.

[0066] For example, after the polymerization reaction is complete, the resulting liquid is further stirred to optimize the structural stability of the polymer chains. Through continuous stirring, the interaction between the emulsifier and the polymer is enhanced, ultimately forming an emulsion with strong binding properties. This binding property allows the flame retardant to form a dense coating layer on the coal surface, isolating it from air and reducing oxidation. This treatment method significantly improves the product's usability.

[0067] For example, after obtaining the high-molecular-weight environmentally friendly flame retardant from the emulsion, its adhesion and stability become key characteristics. In practical applications, this flame retardant, when sprayed onto the coal surface, can quickly form a protective film. This film not only effectively isolates the coal from air but also resists the intrusion of external moisture, thereby suppressing the risk of spontaneous combustion. Compared to traditional water spraying methods, this method does not affect the calorific value of the coal, maintaining its economic value, while also demonstrating environmentally friendly advantages. Through the close integration of the above steps, the entire preparation process is interconnected, ensuring that the final product's performance meets expectations.

[0068] S107. Obtain the surface of the coal pile to be treated, and uniformly cover the surface of the coal pile with the polymer environmentally friendly flame retardant through a spraying device. The spraying process ensures that the flame retardant fully contacts the coal particles.

[0069] The surface morphology data of the coal pile to be processed is acquired, the surface of the coal pile is scanned by a three-dimensional scanning device, and high-precision three-dimensional point cloud data of the surface of the coal pile is generated. Based on the three-dimensional point cloud data of the surface of the coal pile, a geometric model of the surface of the coal pile is constructed, and the point cloud data is converted into a continuous surface grid model by using a triangular meshing method. For the surface grid model of the coal pile, the coverage path of the spraying device is calculated, and a path planning algorithm is used to ensure that the high-molecular environmentally friendly flame retardant uniformly covers the surface grid of the coal pile. The calculated coverage path is transmitted to the spraying device, and the spraying device is controlled to uniformly spray the high-molecular environmentally friendly flame retardant according to the path, so as to ensure that the flame retardant fully contacts the coal particles.

[0070] In a possible implementation, acquiring the surface morphology data of the coal pile to be processed is a key link. The surface of the coal pile usually has an irregular shape and is affected by the stacking method and environmental factors. By using a three-dimensional scanning device such as a laser scanner, the surface of the coal pile can be fully scanned to generate high-precision three-dimensional point cloud data. This data can reflect every detail of the surface of the coal pile, such as convex, concave, or inclined areas. This approach helps to accurately model later and ensures comprehensive coverage of spraying.

[0071] Specifically, it is particularly important to construct a geometric model of the surface of the coal pile based on the above three-dimensional point cloud data. The point cloud data itself is a discrete point set and cannot be directly used for path planning, so it is necessary to convert these points into a continuous surface grid model by using a triangular meshing method. For example, assuming that a coal pile surface has obvious slope changes, triangular meshing can subdivide the slope area into multiple small triangular faces to form an approximate real surface morphology. This model provides a reliable basis for subsequent path calculation, avoids the possibility of missing some areas during spraying, and improves the uniformity of flame retardant distribution.

[0072] In a possible implementation, calculating the coverage path of the spraying device for the constructed surface grid model of the coal pile is a core step of realizing uniform coverage. The path planning algorithm will design the best moving track of the spraying device according to the geometric characteristics of the grid model.

[0073] For example, on a coal pile with large surface undulations, the path planning will preferentially cover the high-convex areas and then gradually transition to the low-concave areas to ensure that each grid cell is covered by the flame retardant. Such a design can effectively improve the spraying efficiency, reduce resource waste, and ensure full contact between the flame retardant and the coal particles.

[0074] Specifically, the calculated coverage path is transmitted to the spraying device and controls its execution, which is the last link of the entire process. The spraying device can be a fixed nozzle or a mobile mechanical arm, which sprays the polymer environmental-friendly flame retardant on the coal pile surface according to the path instructions. For example, in the treatment of a large coal pile, the device may first spray along the edge of the coal pile in a ring shape, and then gradually advance to the central area to ensure that there is no dead angle coverage. This way not only improves the adhesion effect of the flame retardant, but also effectively isolates the air and reduces the risk of coal pile oxidation, providing safer protection for coal storage.

[0075] S108, forming an isolation film layer on the surface of the coal pile, the isolation film layer agglomerates coal particles by the binding effect of the polymer environmental-friendly flame retardant, isolates air, and obtains a treated coal pile.

[0076] The polymer environmental-friendly flame retardant is sprayed on the surface of the coal pile. The flame retardant takes vinyl acetate as the main monomer and forms a liquid substance with adhesive properties through emulsion polymerization reaction. It initially covers the loose particles on the surface of the coal pile to form an initial covering layer. The initial covering layer gradually solidifies on the surface of the coal pile. The covering layer agglomerates the dispersed particles on the surface of the coal pile into a more dense structure through the binding effect of the polymer environmental-friendly flame retardant, forming a first isolation film layer to limit direct contact between air and coal particles. The first isolation film layer further enhances its density during the solidification process, fills the small gaps on the surface of the coal pile, and forms a more complete second isolation film layer to ensure that air cannot penetrate into the interior of the coal pile. After the second isolation film layer is completely solidified, a stable protective structure is formed on the surface of the coal pile. The protective structure continuously maintains the agglomeration state of the coal particles through the binding effect of the polymer environmental-friendly flame retardant, isolates air, and obtains a treated coal pile.

[0077] For example, in actual application, the process of spraying the polymer environmental-friendly flame retardant on the surface of the coal pile can be understood as a means of protecting the coal pile by combining chemical substances with physical coverage. Initially, the flame retardant with vinyl acetate as the main monomer is prepared in liquid form. This liquid substance has strong fluidity and can quickly cover the loose particles on the surface of the coal pile. Assuming that in an open coal yard, the surface of the coal pile is in a loose particle state due to long-term exposure, after spraying, the liquid flame retardant will penetrate between the particles to form a uniform initial covering layer. The role of this covering layer is to provide a basis for subsequent solidification, while initially reducing the opportunity for air to come into contact with coal particles, thereby reducing the possibility of oxidation reaction.

[0078] For example, during the initial stage of gradual solidification of the cover layer, the adhesive properties of the flame retardant begin to take effect. This adhesive property is derived from the cross-linking reaction of the high molecular material under certain conditions, causing the originally dispersed coal particles to be bonded into a more compact whole, forming the first isolation film layer. It is envisaged that in a humid environment, there may be fine moisture on the surface of the coal pile, which will interact with the flame retardant to some extent and accelerate the solidification process. The formation of the first isolation film layer can significantly limit the entry of air into the coal pile, especially in areas where the surface of the coal pile is easily affected by wind. This layer of film acts as a barrier, protecting the internal coal particles from external oxygen intrusion.

[0079] For example, during the process of further enhancing the compactness of the first isolation film layer, it is particularly important to fill the tiny gaps on the surface of the coal pile. Multiple spraying or adjusting the concentration of the flame retardant can be used to ensure the completeness of the coverage, forming the second isolation film layer. In a windy coal yard environment, if the tiny gaps are not filled, they may become channels for air penetration. The formation of the second isolation film layer can effectively solve this problem, ensuring that air cannot penetrate deep into the coal pile. This layer-by-layer coverage makes the protection more complete.

[0080] For example, after the second isolation film layer is completely solidified, the stable protective structure formed on the surface of the coal pile can maintain the agglomeration state of the coal particles for a long time. This structure not only isolates air, but also to some extent, resists the influence of the external environment, such as rainwater erosion. In a long-term storage coal pile scenario, the stable protective structure can reduce the potential risks caused by environmental changes in the coal pile, maintaining the integrity of the coal pile. In this way, the treated coal pile can obtain better protection effect under various conditions, prolong the storage time and reduce losses.

[0081] S109, for the treated coal pile, detect the coverage integrity of the isolation film layer, if an uneven coverage area is detected, supplementally spray the high molecular environmentally friendly flame retardant to the area, to obtain an optimized treated coal pile.

[0082] The image data after spraying the flame retardant on the coal pile surface is obtained, the high-resolution camera is used to take panoramic pictures of the treated coal pile surface to generate first image data. The first image data is divided into multiple regions by image segmentation method to generate a region image set containing pixel distribution of each region. The pixel gray mean value of each region is calculated for the region image set to generate a gray distribution matrix. Based on the gray distribution matrix, the difference between the gray value of each region and the preset threshold is detected to generate a coverage integrity distribution map, and the gray abnormal region is marked as a non-uniform coverage region. The coordinate information of the non-uniform coverage region is extracted from the coverage integrity distribution map to generate a spraying supplement region list. The automatic spraying equipment is used to accurately supplement the spraying of the high-molecular environmentally friendly flame retardant on the non-uniform coverage region according to the spraying supplement region list to generate an optimized coal pile surface image. The optimized coal pile surface image is taken again to generate second image data. Based on the second image data, the region segmentation and gray analysis are repeated to verify the coverage integrity of the isolation film layer on the optimized coal pile surface to generate a final coverage integrity report.

[0083] Specifically, for the image data acquisition process after spraying the flame retardant on the coal pile surface, a high-resolution camera can be used to take panoramic pictures of the coal pile surface to form first image data. This method can capture the fine features of the coal pile surface and ensure the accuracy of subsequent analysis.

[0084] For example, in an open coal yard, the camera can be installed on a fixed support to take pictures of the coal pile surface from multiple angles to ensure coverage of all areas. This has the advantage of comprehensively recording the state after spraying the flame retardant, providing a reliable basis for subsequent detection.

[0085] In one embodiment, for the processing of the first image data, an image segmentation method can be used to divide it into multiple regions to form a region image set. This segmentation method divides the entire image by grid or specific boundary for regional analysis.

[0086] For example, the coal pile surface image can be divided into multiple small squares, each representing an independent region. This approach has the advantage of refining the analysis range and accurately locating possible problem areas to lay the foundation for subsequent coverage integrity detection.

[0087] It should be noted that for the gray analysis of the region image set, the pixel gray mean value of each region is calculated to generate a gray distribution matrix, and the difference with the preset threshold is detected based on this to form a coverage integrity distribution map.

[0088] For example, if the gray value in a certain region is significantly lower, it may indicate that the flame retardant coverage is insufficient and an effective isolation film layer has not been formed. This detection method has the advantage of quickly identifying non-uniform coverage regions and providing clear targets for subsequent supplemental spraying.

[0089] Specifically, the coordinate information of uneven coverage areas is extracted from the coverage integrity distribution map, a list of supplementary spraying areas is formed, and precise supplementation is performed using an automated spraying device.

[0090] For example, on the surface of a coal pile, some edge areas are detected to be under-coverage, and the device can direct the spraying of polymer environmental protection flame retardant according to the coordinate information. The advantage of this method is to avoid resource waste, while improving the uniformity of flame retardant coverage, ensuring the effective isolation of the coal pile from the air.

[0091] In one embodiment, for the surface of the coal pile after optimization processing, second image data can be generated by secondary shooting, and region segmentation and gray scale analysis can be repeated to verify the coverage integrity of the isolation film layer, and finally a coverage integrity report is formed.

[0092] For example, after supplementary spraying, the surface of the coal pile is photographed again to analyze whether the gray scale distribution tends to be consistent to confirm whether the flame retardant effect meets the expectation. The benefit of this verification process is to ensure the treatment effect and avoid missing problem areas, thereby improving the safety of the coal pile.

[0093] It should be noted that the above various links are closely connected, from image acquisition to coverage detection, to supplementary spraying and effect verification, forming a complete closed-loop process.

[0094] For example, the initial image data provides a basis for subsequent gray scale analysis, and the results of gray scale analysis directly guide the implementation of supplementary spraying, and the final verification link ensures the overall effect. This interlocking method not only improves the accuracy of detection and processing, but also significantly reduces the risk of spontaneous combustion of the coal pile, ensuring the safety during storage.

[0095] S1010, according to the storage environment of the coal pile after optimization processing, the state of the isolation film layer is checked regularly, and if the film layer is found to be damaged, the polymer environmental protection flame retardant is sprayed again to maintain the isolation effect.

[0096] The covering state data of the isolation film layer is obtained from the coal pile storage environment. By regularly scanning the surface of the coal pile, whether the film layer has damaged or peeled areas is recorded, and a covering state report is generated. For the damaged areas found in the covering state report, the specific location and range that need to be repaired are determined, the pre-established spraying path planning is used for accurate positioning of the damaged areas, and a repair area distribution map is generated. According to the repair area distribution map, the spraying amount and spraying path of the high-molecular environmentally friendly flame retardant are adjusted, and the damaged areas are covered again by the automatic spraying equipment to form a new isolation film layer. The covering state after spraying is recorded. The updated film layer integrity data is extracted from the covering state after spraying, and the covering state reports before and after repair are compared to determine whether the isolation film layer meets the preset integrity requirement, ensuring the effective isolation of the coal pile from the air and maintaining the isolation effect.

[0097] Specifically, for the acquisition of the covering state of the isolation film layer in the coal pile storage environment, regular surface scanning can be used. For example.

[0098] In one possible implementation, a high-resolution camera can be installed on a mobile track to scan the surface of the coal pile comprehensively and capture subtle damage or peeling traces of the film layer. This approach can quickly detect tiny cracks that are difficult to detect with the naked eye, providing accurate basis for subsequent repair. This not only improves the accuracy of detection, but also avoids the decline of isolation effect due to oversight, thereby protecting the coal pile from air oxidation.

[0099] Next, for accurate positioning of the damaged areas and determination of the repair range, the covering state report generated by scanning can be used.

[0100] In one possible implementation, assuming that the surface of the coal pile is divided into multiple grid areas, by comparing the film layer integrity data of each grid, the damaged location is quickly locked, and combined with the pre-established spraying path planning, a repair area distribution map is drawn. The advantage of this approach is that it can target problem areas, reduce resource waste, and ensure the efficiency and comprehensiveness of repair work, providing clear guidance for subsequent spraying.

[0101] Further, when implementing the re-spraying of the high-molecular environmentally friendly flame retardant, the automatic spraying equipment can be used to complete the covering work.

[0102] For example, the equipment can automatically adjust the nozzle angle and spraying amount according to the repair area distribution map to ensure that the flame retardant uniformly covers the damaged areas and forms a new isolation film layer. This automated operation can significantly improve the uniformity and efficiency of spraying, avoiding unevenness or omissions that may be caused by manual operation, thereby better maintaining the isolation effect and reducing the opportunity for the coal pile to come into contact with the air.

[0103] Finally, in the verification process of the film layer integrity after the spraying is completed, the updated coverage state data can be extracted again through the scanning device, and compared with the report before the repair.

[0104] In a possible implementation, if it is found that the film layer thickness or coverage of a certain area does not reach the expectation, it can be recorded and trigger local supplementary spraying. This comparison and verification method can ensure that the repaired film layer reaches the preset isolation standard, continuously protects the coal pile from oxidation and spontaneous combustion risk, and prolongs the storage safety period.

[0105] The above is only a specific implementation of the present specification, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described here. It should be understood that the protection scope of the present specification is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present specification, and these modifications or replacements should be covered within the protection scope of the present specification.

Claims

1. A high molecular environmentally friendly flame retardant, characterized in that, Its composition is composed of: Vinyl acetate: 10-12 parts; Methyl methacrylate: 1-3 parts; Butyl acrylate: 1-2 parts; Sodium dodecyl sulfate 3-8 parts; Water 75-85 parts.

2. A method for preparing the high molecular environmentally friendly flame retardant according to claim 1, characterized in that, Specifically comprising the following steps: Step (1) mix vinyl acetate and methyl methacrylate uniformly; Step (2) dissolve butyl acrylate in water, and mix them uniformly; Step (3) complete the mixing of reagents and water, and fuse them; Step (4) add sodium dodecyl sulfate to the above mixture, mix and fuse; stir for 1h until all reagents and solutions are mixed uniformly, that is, the flame retardant is synthesized.

3. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 2, characterized in that, Including: Obtain vinyl acetate, methyl methacrylate, butyl acrylate, sodium dodecyl sulfate and water as raw materials; Mix the raw materials in a predetermined ratio and carry out emulsion polymerization to obtain a flame retardant; Form a covering layer on the surface of coal by the flame retardant to inhibit spontaneous combustion of coal.

4. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 3, characterized in that, Said raw materials are mixed in a predetermined ratio and emulsion polymerized, including: Mixing vinyl acetate and methyl methacrylate uniformly to obtain a first mixture; Dissolve butyl acrylate in water to obtain a second mixture; Fuse the first mixture with the second mixture to obtain a third mixture; Add sodium dodecyl sulfate to the third mixture, stir until uniform, complete emulsion polymerization, and obtain the flame retardant.

5. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 3, characterized in that, Said obtaining vinyl acetate, methyl methacrylate, butyl acrylate, sodium dodecyl sulfate and water as raw materials, including: According to the mass percentage, obtain 10-12 parts of vinyl acetate, 1-3 parts of methyl methacrylate, 1-2 parts of butyl acrylate, 3-8 parts of sodium dodecyl sulfate and 75-85 parts of water as raw materials.

6. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 2, characterized in that, Said forming a covering layer on the surface of coal by the flame retardant, including: Spray the flame retardant on the surface of coal; Through the cohesive effect of the flame retardant, the coal particles are agglomerated to form a solidified covering layer; Isolate coal from air through the solidified covering layer to inhibit coal oxidation.

7. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 3, characterized in that, Said adding sodium dodecyl sulfate to the third mixture and stirring until uniform, including: Add sodium dodecyl sulfate to the third mixture; Stir the third mixture with added sodium dodecyl sulfate for 1 hour by stirring equipment to obtain a uniform emulsion polymerization product; Determine the flame retardant by the emulsion polymerization product.

8. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 5, characterized in that, Said isolating coal from air through the solidified covering layer, including: Reduce the contact area between the surface of coal and oxygen through the solidified covering layer; Reduce the gap between coal particles through the solidified covering layer to limit air penetration; According to the covering effect of the solidified covering layer, determine the degree of reduction of the risk of spontaneous combustion of coal.

9. The preparation method of the polymer-based environmentally friendly flame retardant according to claim 4, characterized in that, Said according to the mass percentage, obtain 10-12 parts of vinyl acetate, 1-3 parts of methyl methacrylate, 1-2 parts of butyl acrylate, 3-8 parts of sodium dodecyl sulfate and 75-85 parts of water as raw materials, including: Determine the mass percentage of each raw material; According to the mass percentage, measure the vinyl acetate, methyl methacrylate, butyl acrylate, sodium dodecyl sulfate and water respectively; Determine the raw material combination for emulsion polymerization by the measured raw materials.

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