Chlorine-free environment-friendly coal transportation and storage antifreezing agent and preparation method thereof

Abstract

The application discloses a kind of chlorine-free environment-friendly coal transportation and storage antifreeze and preparation method thereof, belong to coal storage and transportation technical field, the preparation method of the chlorine-free environment-friendly coal transportation and storage antifreeze, comprising the following steps: natural oil is heated and stirred, vacuum dewatering is carried out, then amine compound is added to modify reaction, after reaction is finished, cooling is obtained Intermediate product 1, water, thickening agent and metal corrosion inhibitor are added to it again, stir uniformly, obtain the chlorine-free environment-friendly coal transportation and storage antifreeze.I.e. the antifreeze prepared in the application forms weak interface on the surface of coal and carriage or warehouse, is easy to destroy, prevents "freezing vehicle phenomenon";And no chlorine component is used, fundamentally eliminates the corrosion problem caused by chloride ion;It is relatively simple to clean simultaneously because it has certain emulsifying capacity itself;And raw material is more natural oil or recycled oil, with the advantages of green environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of coal storage and transportation technology, and particularly relates to a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage and its preparation method. Background Technology

[0002] To improve thermal efficiency and safety, coal is typically washed (or prepared) before transportation or storage, a refining process. However, this process increases the moisture content of the processed coal, generally between 6.5% and 14%. Studies have shown that when the moisture content exceeds 8%, the coal's freeze-thaw resistance increases significantly, especially in cold northern regions during winter. This can cause the coal to freeze during transportation, leading to loading and unloading difficulties and severely impacting transportation efficiency.

[0003] To address the problem of coal freezing during transportation due to high moisture content, various methods have been tried both domestically and internationally, such as vibration, blasting, electric heating, and freezing storage. However, these methods have shortcomings in terms of effectiveness, operability, and cost. Currently, a commonly used measure is to spray antifreeze agents on the coal surface to lower the freezing point of water. Calcium chloride, due to its significant pour point depressant effect and low price, is often used as the inorganic pour point depressant component in coal antifreeze agents. Patent publication CN101381594A discloses a formulation and preparation method for a coal antifreeze agent, specifically composed of: 1-3 parts by weight of sodium carboxymethyl cellulose, 5-15 parts by weight of magnesium chloride, 5-15 parts by weight of calcium chloride, 0.05-0.2 parts by weight of boric acid, and 75-80 parts by weight of water. The preparation steps of the antifreeze are as follows: (1) Add half of the component water to reactor No. 1, slowly add sodium carboxymethyl cellulose at room temperature and pressure and stir until completely dissolved; (2) Add the remaining half of the component water to reactor No. 2, slowly add calcium chloride, magnesium chloride and boric acid at room temperature and pressure and stir until completely dissolved; (3) Mix the solutions in reactors No. 1 and No. 2 into reactor No. 3 and stir at room temperature for 20 minutes to obtain the antifreeze. Although the addition of chloride can effectively lower the freezing point, its excessive use will lead to excessive chlorine content in coal, affecting coal export and increasing the emission of harmful pollutants during combustion. In addition, chloride will accelerate the corrosion of transportation and combustion equipment and shorten the service life of equipment. The patent with publication number CN 112251195 A discloses a chlorine-free coal transportation antifreeze. Its principle has not changed compared with the above patent. The difference is that the patent uses organic substances or organic salt solutes such as polyethylene glycol and glycerol, sodium formate and sodium acetate. Existing antifreeze agents operate on the colligative property of solutions (Raoult's law), lowering the freezing point by reducing the proportion of water. This means that existing patents, while effective in delaying the freezing process, do not effectively prevent coal from freezing and adhering to the metal surfaces of the car body. Once freezing occurs, significant manpower or machinery is required for ice breaking and cleaning, resulting in low loading and unloading efficiency and poor operational safety. Furthermore, organic matter or salt solvents in these agents easily leave residues on the car body surface, which are difficult to clean and thus affect subsequent antifreeze performance. In addition, petroleum jelly also presents the problem of being difficult to clean.

[0004] Therefore, there is an urgent need to develop a new chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage that forms a weak interface, ensuring antifreeze performance while also being highly efficient, environmentally friendly, and easy to clean. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage, and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage includes the following steps:

[0008] Natural oils are heated and stirred, then dehydrated under vacuum. Sodium hydroxide and amine compounds are added sequentially for modification. After the reaction is completed, the mixture is cooled to obtain intermediate product 1. Water, thickener, and metal corrosion inhibitor are then added to the intermediate product 1 and stirred until homogeneous to obtain the chlorine-free environmentally friendly antifreeze agent for coal transportation and storage.

[0009] In a further preferred embodiment, after obtaining intermediate product 1, the step of adding an acid anhydride compound to carry out an esterification reaction is further included, that is: adding an acid anhydride compound to intermediate product 1 to carry out an esterification reaction to obtain intermediate product 2, and then adding water, thickener and metal corrosion inhibitor to it, stirring evenly to obtain the chlorine-free environmentally friendly coal transportation and storage antifreeze agent.

[0010] In a further preferred embodiment, after obtaining intermediate product 2, the step of adding a sulfonating agent to carry out a sulfonation reaction is also included, namely: adding water and a sulfonating agent to the intermediate product 2 to carry out a sulfonation reaction, and after the reaction is completed, adding a thickener and a metal corrosion inhibitor, stirring evenly, to obtain the chlorine-free environmentally friendly coal transportation and storage antifreeze agent.

[0011] Beneficial Effects: This invention provides a method for preparing a chlorine-free, environmentally friendly antifreeze for coal transportation and storage. Through a series of chemical modification processes, natural oils are transformed into a composite functional antifreeze with excellent antifreeze properties, easy cleaning, and good stability. This preparation process not only avoids the corrosiveness, environmental pollution, and coal quality contamination problems caused by traditional chloride antifreeze agents, but also innovatively adopts the technical concept of "forming a weak interface," fundamentally solving the problem of difficult loading and unloading of coal in cold regions due to freezing during transportation and storage.

[0012] The entire preparation process of this invention uses natural oils as starting materials. Through heating, stirring, and vacuum dehydration, water in the oils is effectively removed, preventing hydrolysis or oxidation side reactions during subsequent high-temperature reactions and ensuring the stability of the reaction system and product quality. Subsequently, in the presence of the alkaline catalyst sodium hydroxide, amine compounds are added for modification. This reaction is mainly amidation or ester amination, causing the triglycerides in the natural oils to react with the amines to generate surface-active amide derivatives. These products not only enhance the polarity and hydrophilicity of the oils but also endow them with certain emulsifying abilities. This allows them to effectively adhere to metal surfaces to form a protective layer during subsequent use and to be emulsified and dispersed by the aqueous system during cleaning, significantly improving cleaning convenience.

[0013] Based on intermediate product 1, an acid anhydride compound is further introduced to carry out an esterification reaction, generating a modified oil product with a carboxyl group (intermediate product 2). This step not only increases the molecular polarity and enhances its adsorption capacity to the metal surface, but also provides active sites for the subsequent sulfonation reaction. Next, a sulfonating agent is added, and a sulfonation reaction is carried out under mild conditions to introduce hydrophilic sulfonic acid groups (–SO3). - This further enhances the water solubility and emulsifying properties of the product. This series of chemical modifications enables the final product to form a thin and uniform oily barrier film between the coal and the car body, effectively weakening the bonding strength of the frozen interface and achieving a "weak interface" effect. This allows the frozen coal to be easily peeled off under external force, avoiding the "frozen car" phenomenon.

[0014] Furthermore, the addition of hydroxyethyl cellulose as a thickener during the preparation process significantly improves the viscosity and adhesion of the antifreeze, preventing excessive flow on the vehicle surface and ensuring uniform coverage and long-term retention after spraying, thus enhancing antifreeze efficiency. The composite metal corrosion inhibitor composed of benzotriazole and borax effectively inhibits the electrochemical corrosion process on metal surfaces without compromising overall environmental performance, protecting transport vehicles and coal storage equipment and extending their service life. Additionally, the invention can selectively add mineral oil components such as liquid paraffin or dimethyl silicone oil to further optimize the antifreeze's flowability, film-forming properties, and low-temperature stability, broadening its applicability in low-temperature environments.

[0015] In summary, this invention constructs a chlorine-free, environmentally friendly antifreeze agent with integrated structure and function through multi-step chemical modification. Its core advantages lie in: abandoning the traditional colligative principle of "lowering the freezing point," it instead achieves antifreeze by constructing a "weak interface," fundamentally avoiding the harm of chloride ions to coal quality and equipment; simultaneously, utilizing natural oils as raw materials, combined with the synergistic effects of emulsifying, thickening, and corrosion-inhibiting components, it achieves multiple technological breakthroughs, including excellent antifreeze performance, environmental friendliness, and ease of cleaning. This antifreeze agent is suitable for large-scale coal storage and transportation scenarios and aligns with the direction of green and low-carbon development, possessing broad market prospects and significant application value.

[0016] Preferably, the mass ratio of the natural oils and amine compounds is (415~440):(80~150); and / or,

[0017] The mass ratio of the metal corrosion inhibitor to the natural oil is (12~24):(415~440); and / or,

[0018] The mass ratio of the thickener to the natural oil is (4~9):(415~440); and / or,

[0019] The mass ratio of the acid anhydride compound to the natural oil is (100~150):(415~440); and / or,

[0020] The mass ratio of the sulfonating agent to the natural oil is 340:415.

[0021] Optionally, the natural oil is one or a mixture of soybean oil, rapeseed oil, palm oil, lard, and tallow.

[0022] Optionally, the metal corrosion inhibitor includes benzotriazole and borax; the mass ratio of the two is 2:1.

[0023] Optionally, the thickener is hydroxyethyl cellulose.

[0024] Optionally, the amine compound is selected from at least one of monoethanolamine, diethanolamine, and ethylenediamine.

[0025] Optionally, the anhydride compound is selected from at least one of maleic anhydride, succinic anhydride, phthalic anhydride, and pyromellitic anhydride.

[0026] Optionally, the sulfonating agent is sodium metabisulfite or sodium bisulfite.

[0027] Optionally, the raw materials of the chlorine-free environmentally friendly coal transportation and storage antifreeze agent also include mineral oil; the mineral oil is liquid paraffin or dimethyl silicone oil; the mineral oil is added at the same time as natural oils.

[0028] Optionally, the modification reaction conditions are: reacting at 120-160℃ for 2 hours.

[0029] Optionally, the esterification reaction is carried out at 80-85°C for 4 hours.

[0030] Optionally, the sulfonation reaction is performed at 80-85°C for 0.5 hours.

[0031] A chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage is prepared by the above-mentioned preparation method.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] The antifreeze prepared by this invention exhibits excellent comprehensive performance and environmental advantages in practical applications. Its core mechanism lies in the chemical modification of natural oils into functional substances with special interfacial properties, thereby forming a uniform, stable, but weakly bonded isolation interface layer between coal and the metal surface of transport vehicles or storage warehouses. This "weak interface" structure maintains good flexibility and integrity even at low temperatures, effectively preventing direct contact between coal particles and the metal surface, significantly reducing freezing intensity. Even if the coal freezes slightly under extremely cold conditions, it can be easily peeled off under external forces such as mechanical vibration, unloading, or simple impact, completely avoiding the "frozen truck" problem common in traditional transportation and greatly improving loading and unloading efficiency and operational safety. Crucially, this invention completely eliminates chlorine-containing inorganic salts such as calcium chloride and sodium chloride, fundamentally eliminating the risk of electrochemical corrosion of metal equipment by chloride ions. This not only extends the service life of transport vehicles, coal bunkers, and conveying equipment but also avoids technical barriers to coal combustion quality and export trade caused by excessive chlorine content. More notably, the antifreeze prepared in this invention incorporates hydrophilic groups such as amide, carboxyl, and sulfonic acid groups into its molecular structure, giving it a certain degree of self-emulsification ability. During post-use cleaning, the antifreeze can be rapidly emulsified and dispersed by water, making it easy to rinse clean and preventing the formation of stubborn oil film residue on the vehicle's surface. This ensures the effectiveness and uniformity of subsequent antifreeze application. Furthermore, this invention preferentially uses renewable natural oils such as soybean oil, rapeseed oil, and palm oil as its main raw materials. These oils are widely available, biodegradable, and align with the principles of green chemistry and sustainable development, truly achieving…

[0034] It ensures environmental friendliness throughout the entire process from raw materials to application. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 The images show the cleaning effect after applying the antifreeze prepared in Example 1 of this invention and the petroleum jelly in Comparative Example 2; a is the original state of the galvanized steel surface; b is the state after application, where the left image shows petroleum jelly applied and the right image shows the antifreeze from Example 1 applied; c is the state after rinsing with tap water for 4 seconds, where the left image shows petroleum jelly and the right image shows the antifreeze from Example 1. Detailed Implementation

[0037] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0038] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0039] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0040] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0041] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0042] This invention provides a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage, and its preparation method. The raw materials for this chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage include: oils (animal and vegetable oils and mineral oils), modifiers, metal corrosion inhibitors, thickeners, and water.

[0043] This invention discloses a method for preparing a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage, comprising one or more of the following steps:

[0044] 1. Natural oils are melted at high temperatures, and the first step of modification is carried out using small molecule reactions containing active groups;

[0045] 2. Esterification with acid anhydrides is used as the second step of modification;

[0046] 3. A sulfonating agent is then added to carry out a sulfonation reaction, which is the third step of modification;

[0047] 4. Add other ingredients and mix.

[0048] In some alternative embodiments, the natural oil is one or a mixture of more of the following: soybean oil, rapeseed oil, palm oil, lard, and tallow.

[0049] In some alternative embodiments, the small molecule used in the first step of modification is one or more of monoethanolamine, diethanolamine, and ethylenediamine.

[0050] In some optional embodiments, the anhydride compound in the second step of modification is one or more of maleic anhydride, succinic anhydride, phthalic anhydride, and pyromellitic anhydride.

[0051] In some alternative embodiments, the sulfonating agent used in the third step of modification is sodium metabisulfite or sodium bisulfite.

[0052] In addition, to ensure the performance of the prepared antifreeze, other conventional additives, such as emulsifiers, can be selectively added to the above formula.

[0053] The antifreeze prepared by this invention forms a weak interface (similar to the fragile interface of butter) on the surface of coal and the car body or warehouse, which is easily broken and prevents the "frozen car phenomenon"; it does not use chlorine-containing components, thus fundamentally eliminating the corrosion problem caused by chloride ions; at the same time, because it has a certain emulsification ability, it is relatively simple to clean; and the raw materials mostly use natural oils, which is green and environmentally friendly.

[0054] All raw materials used in this invention were purchased from the market.

[0055] The technical solution of the present invention will be further illustrated by the following embodiments.

[0056] Example 1 Oil Modification 1

[0057] A method for preparing a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage includes the following steps:

[0058] Add 430 kg of rapeseed oil to the reactor, heat and start stirring. After the temperature reaches 105℃, start vacuum dehydration for 15-30 min. Continue heating to 120℃, add 0.5 kg of flake sodium hydroxide and 147 kg of diethanolamine, and react for 2 h. After the reaction is completed, cool down to 50℃ and add 200 kg of warm water (the water temperature should not be lower than 30℃). Then add 4 kg of hydroxyethyl cellulose and stir continuously for more than 30 min. Then add metal corrosion inhibitor (8 kg of benzotriazole and 4 kg of borax), stir for another 15 min, and then discharge to prepare a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage.

[0059] Example 2 Oil Modification 2

[0060] A method for preparing a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage includes the following steps:

[0061] Add 440 kg of soybean oil to a reactor, heat until no solids remain, then start stirring. Continue heating to 105°C, then begin vacuum dehydration for 15-30 minutes. Continue heating to 160°C, then add 0.5 kg of flake sodium hydroxide, 53 kg of diethanolamine, and 30 kg of monoethanolamine, and react for 2 hours. After the reaction, cool down to 85°C and add 150 kg of phthalic anhydride, maintaining the temperature at 80°C for 4 hours. After the temperature is maintained, add 700 kg of water and 7 kg of hydroxyethyl cellulose. Cool down to 40°C and add 100 kg of 40 wt% sodium hydroxide solution. Stir for 15 minutes, then add a metal corrosion inhibitor (14 kg of benzotriazole and 7 kg of borax), stir for 15 minutes, and then discharge the material to prepare a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage.

[0062] Example 3 Oil Modification 3

[0063] A method for preparing a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage includes the following steps:

[0064] Add 415 kg of 10°C palm oil (where 10°C is the melting point of palm oil) to a reactor. Heat to melt it into a liquid, then start stirring. Continue heating to 105°C, then begin vacuum dehydration for 15-30 minutes. Continue heating to 140°C, then add 0.5 kg of flake sodium hydroxide, 53 kg of diethanolamine, and 30 kg of monoethanolamine. React for 2 hours. After the reaction is complete, cool down to 85°C, then add 100 kg of maleic anhydride and maintain the temperature at 80°C for 4 hours. After the temperature is maintained at 80°C, add 800 kg of warm water (not exceeding 50°C) and 340 kg of 30 wt% sodium bisulfite solution. 20 kg of 40 wt% sodium hydroxide solution was added and the reaction was maintained at 80℃ for 30 min. 9 kg of hydroxyethyl cellulose was added and the mixture was stirred for 1.5 h. The mixture was then cooled to 40℃ and metal corrosion inhibitor (16 kg of benzotriazole and 8 kg of borax) was added. After stirring for another 15 min, the mixture was discharged to prepare a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage.

[0065] Example 4: Oil-modified 2+ oil compound

[0066] The preparation method of a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage differs from Example 2 only in that...

[0067] In the initial preparation stage of Example 2, 80 kg of liquid paraffin was added, with the rest remaining unchanged, to prepare a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage.

[0068] Example 5: Oil-modified 3+ oil compound

[0069] The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage differs from Example 3 only in that...

[0070] In the initial preparation stage of Example 3, 20 kg of dimethyl silicone oil was added, with the rest remaining unchanged, to prepare a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage.

[0071] To demonstrate that the fragile layer formed by the antifreeze prepared according to this invention improves the problem of frozen vehicles, rather than the surface activity of the modified antifreeze, comparative examples 1-2 were provided. The comparisons demonstrate that the purpose of the modification in this invention is to form a fragile layer without being as difficult to clean as pure oil.

[0072] Comparative Example 1

[0073] A traditional inorganic salt antifreeze was formulated based on common antifreeze formulas on the market. Its main component is calcium chloride, and it is compounded with other components.

[0074] The specific formula (parts by weight) is shown in Table 1.

[0075] Table 1

[0076]

[0077] Comparative Example 2

[0078] Use petroleum jelly paste.

[0079] Figure 1 Images show the cleaning effect after applying the antifreeze prepared in Example 1 of this invention and the petroleum jelly in Comparative Example 2; a) shows the original state of the galvanized steel surface; b) shows the state after application, where the left image is petroleum jelly and the right image is the antifreeze from Example 1; c) shows the state after rinsing with tap water for 4 seconds, where the left image is petroleum jelly and the right image is the antifreeze from Example 1. Figure 1 As can be seen, after applying 0.08g of petroleum jelly and rinsing with tap water, droplets remained on the surface, indicating that the surface was not clean. However, after applying 0.3g of the antifreeze agent of this invention, the surface was clean. This proves that the antifreeze agent prepared by this invention has a certain emulsifying ability, making it simple and clean to clean.

[0080] Effect verification:

[0081] I. The antifreeze effect of this invention is mainly aimed at preventing coal from freezing in the car body. Considering that the antifreeze mechanism of this invention is completely different from that of common antifreeze agents on the market, the freezing point in SH / T 0090-1991 was not used for characterization. Instead, an alternative effect verification test was designed, the process of which is as follows:

[0082] First, a steel trough with dimensions of 240mm (length) × 140mm (width) × 230mm (height) was constructed. During the experiment, a fixed mass (27.6-28.4g) of antifreeze was applied to the surface of the steel trough. (The amount of antifreeze applied in Comparative Examples 1 and 2 was the same as the dry weight of the example.) After application, the trough was placed in a 105℃ oven for 30 seconds. After removal, coal with a fixed moisture content (12%) was added, and the total mass of the added coal (6.5-7kg) was weighed. Then, the trough was left to stand for 5 minutes before being placed in a refrigerator. The refrigerator temperature was adjusted as required; in this experiment, -40℃ was selected. After 24 hours, the trough was emptied, the remaining mass of coal in the trough was measured, and the coal residue percentage was calculated. Specific data are shown in Table 2.

[0083] Table 2. Results of Conventional Performance Tests for Coal Antifreeze

[0084]

[0085] II. The metal corrosion resistance of the antifreeze agents in Examples 1-5 and Comparative Examples 1-2 was tested according to JB / T 7901. Four steel sheets, four aluminum sheets, four stainless steel sheets, and four copper sheets with dimensions of 50mm×50mm×2mm were obtained and immersed in the coal antifreeze agents of Examples 1-5 and Comparative Examples 1-2, respectively. The immersion time was specified in the standard. After the experiment, the metal sheets were removed and the corrosion was observed. The test results are shown in Table 3.

[0086] Table 3 Corrosion Rate

[0087]

[0088] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage, characterized in that, Includes the following steps: Natural oils are heated and stirred, then dehydrated under vacuum. Amine compounds are added for modification. After the reaction is completed, the mixture is cooled to obtain intermediate product 1. Water, thickener and metal corrosion inhibitor are then added to the intermediate product 1 and stirred evenly to obtain the chlorine-free environmentally friendly coal transportation and storage antifreeze agent. or, Natural oils are heated, stirred, and dehydrated under vacuum. Then, amine compounds are added for modification. After the reaction is completed, the mixture is cooled to obtain intermediate product 1. An acid anhydride compound is added to intermediate product 1 for esterification to obtain intermediate product 2. Water, thickener, and metal corrosion inhibitor are then added to intermediate product 2 and stirred evenly to obtain the chlorine-free environmentally friendly coal transportation and storage antifreeze agent. or, Natural oils are heated, stirred, and dehydrated under vacuum. Then, amine compounds are added for modification. After the reaction is completed, the mixture is cooled to obtain intermediate product 1. An acid anhydride compound is added to intermediate product 1 for esterification to obtain intermediate product 2. A sulfonating agent is added to intermediate product 2 for sulfonation. Water, thickener, and metal corrosion inhibitor are then added and stirred evenly to obtain the chlorine-free environmentally friendly coal transportation and storage antifreeze agent. The metal corrosion inhibitors include benzotriazole and borax.

2. The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage according to claim 1, characterized in that, The mass ratio of the natural oils and amine compounds is (415~440):(80~150); and / or, The mass ratio of the metal corrosion inhibitor to the natural oil is (12~24):(415~440); and / or, The mass ratio of the thickener to the natural oil is (4~9):(415~440); and / or, The mass ratio of the acid anhydride compound to the natural oil is (100~150):(415~440); and / or, The mass ratio of the sulfonating agent to the natural oil is 340:

415.

3. The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage according to claim 1, characterized in that, The natural oil is selected from at least one of soybean oil, rapeseed oil, palm oil, lard, and tallow; and / or, The thickener is hydroxyethyl cellulose; and / or, The amine compound is selected from at least one of monoethanolamine, diethanolamine, and ethylenediamine; and / or, The acid anhydride compound is selected from at least one of maleic anhydride, succinic anhydride, phthalic anhydride, and pyromellitic anhydride; and / or, The sulfonating agent is sodium metabisulfite or sodium bisulfite.

4. The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage according to claim 1, characterized in that, The raw materials of the chlorine-free environmentally friendly coal transportation and storage antifreeze agent also include liquid paraffin or dimethyl silicone oil; the timing of adding the liquid paraffin or dimethyl silicone oil is the same as that of natural oils.

5. The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage according to claim 1, characterized in that, The conditions for the modification reaction are: reaction at 120-160℃ for 2 hours.

6. The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage according to claim 1, characterized in that, The esterification reaction was carried out at 80-85℃ for 4 hours.

7. The preparation method of a chlorine-free environmentally friendly antifreeze agent for coal transportation and storage according to claim 1, characterized in that, The sulfonation reaction conditions are: reaction at 80-85℃ for 0.5h.

8. A chlorine-free, environmentally friendly antifreeze agent for coal transportation and storage, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

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