Efficient dry powder extinguishing agent and preparation method thereof

Abstract

The invention relates to the technical field of dry powder extinguishing agents, in particular to an efficient dry powder extinguishing agent and a preparation method thereof. A preparation method of the efficient dry powder extinguishing agent comprises the following steps: uniformly mixing a sodium silicate solution and silica sol, adding aluminum nitrate into the mixture, stirring at 40-50 DEG C, adding hexadecyl trimethyl ammonium bromide into the mixture, carrying out ultrasonic treatment for 10-30 minutes, carrying out hydrothermal treatment, cooling to room temperature, filtering, drying, calcining at 300-350 DEG C for 10-30 minutes, cooling and crushing to obtain a porous composite material; adding anhydrite into the porous composite material, mixing, carrying out ball milling, screening, adding potassium sulfate, sodium bicarbonate, nano hydrophobic silicon dioxide, chlorinated rubber and water, mixing, grinding for 10-30 minutes, and carrying out ultrasonic treatment for 10-20 minutes to obtain a prefabricated material; uniformly mixing polyimide fibers and silicon nitride, adding silicone oil and zinc borate, uniformly mixing, adding the prefabricated material, uniformly stirring, sintering in vacuum, cooling, crushing and screening.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dry powder extinguishing agent, in particular to a high-efficiency dry powder extinguishing agent and a preparation method thereof. BACKGROUND

[0002] As an important fire extinguishing material, dry powder extinguishing agent is widely used in various fire extinguishing fields. It is mainly micron-sized particles prepared by mixing and grinding fire extinguishing base material, lubricant and a small amount of moisture-proof agent, and high-concentration dust cloud is formed by compressed gas injection to achieve fire extinguishing by covering the surface of the burning material to isolate oxygen, release inert gas to reduce oxygen concentration and interrupt the combustion chain reaction.

[0003] Compared with traditional water-based, foam and gas extinguishing agents, dry powder extinguishing agent has the characteristics of dry and easy flow, excellent moisture-proof and anti-caking performance, high storage stability and wide application range, especially for oil fires, which can effectively extinguish initial oil fires and become an important fire-fighting means in high-risk places such as oil tank area and chemical plant.

[0004] However, ordinary dry powder extinguishing agent mainly extinguishes fire by chemical inhibition, lacks physical cooling capacity, and its hydrophobic and lipophilic characteristics and large particle size cause the extinguishing agent particles to sink to the bottom of the oil, making it difficult to continuously cover the burning surface and effectively block the contact between combustible vapor and oxygen. At the same time, the surface temperature of the residual oil after extinguishing is still higher than the self-ignition point, and combined with the influence of heat radiation and external fire source, it is easy to cause reignition. This defect is particularly prominent in large oil tank area fires, and traditional dry powder is difficult to form effective coverage on the three-dimensional burning surface due to poor adhesion and insufficient flowability, resulting in a significant decrease in extinguishing efficiency.

[0005] At present, how to provide a dry powder extinguishing agent with high-efficiency cooling, anti-reignition and strong adhesion has become a research hotspot for improving the comprehensive performance of dry powder, which has important practical significance. SUMMARY

[0006] The present application relates to the technical field of dry powder extinguishing agent, in particular to a high-efficiency dry powder extinguishing agent and a preparation method thereof.

[0007] A preparation method of a high-efficiency dry powder extinguishing agent, comprising the following steps: S1, uniformly mix sodium silicate solution and silica sol, add aluminum nitrate to adjust the pH value of the system to 8-9.5, stir at 40-50℃ for 1-2h, add cetyltrimethylammonium bromide and ultrasonic treat for 10-30min, hydrothermal treatment at 170-180℃ for 5-10h, cool to room temperature, filter, vacuum dry, calcine at 300-350℃ for 10-30min, cool to room temperature, and crush to obtain a porous composite material; S2. Add hard gypsum to the porous composite material and mix. Ball mill for 1-2 hours, sieve, add potassium sulfate, sodium bicarbonate, nano hydrophobic silica, chlorinated rubber and water, mix and grind for 10-30 minutes, and ultrasonically treat for 10-20 minutes to obtain the preform. S3. Mix polyimide fiber and silicon nitride evenly, add silicone oil and zinc borate and mix evenly, add pre-made material and stir evenly, vacuum sinter at 150-220℃ for 10-30 minutes, cool naturally to room temperature, crush and sieve.

[0008] Preferably, in S1, the mass fraction of sodium silicate solution is 10-20%, the mass fraction of silica sol is 5-15%, and the ratio of sodium silicate solution, silica sol, aluminum nitrate, and hexadecyltrimethylammonium bromide is 10-30:5-15:3-8:1-2.

[0009] Preferably, in S1, a sodium hydroxide solution with a concentration of 1-2 mol / L is used to adjust the pH of the system to 8-9.5.

[0010] Preferably, in S1, the ultrasonic frequency is 40-50 kHz.

[0011] Preferably, in S2, the mass ratio of porous composite material, anhydrite, potassium sulfate, sodium bicarbonate, nano-hydrophobic silica, chlorinated rubber, and water is 6-20:1-3:25-40:8-15:2-4:2-4:3-5.

[0012] Preferably, in S2, the ball milling speed is 300-500 r / min.

[0013] Preferably, in step S2, particles with a size ≤20μm are obtained by sieving.

[0014] Preferably, in S2, the ultrasonic frequency is 40-60kHz.

[0015] Preferably, in S2, the nano-hydrophobic silica is nano-silica with perfluoroalkyl chains grafted onto its surface.

[0016] Preferably, in S3, the diameter of the polyimide fiber is 0.1-1 μm, and the mass ratio of polyimide fiber, silicon nitride, silicone oil, zinc borate, and preform is 2-5:1-2:1-3:1-2:50-100.

[0017] Preferably, A high-efficiency dry powder fire extinguishing agent is prepared by the above-mentioned preparation method for high-efficiency dry powder fire extinguishing agents.

[0018] Beneficial effects: This invention utilizes the hydrolysis of aluminum nitrate to generate Al(OH)3 sol, which is then orderly adsorbed onto the porous surface of silicate under the action of hexadecyltrimethylammonium bromide. Through hydrothermal treatment and calcination, a dense coating layer is formed, giving the product not only good flowability and smoke adsorption properties, but also forming a gradient endothermic structure when combined with anhydrite. When the extinguishing agent comes into contact with a high-temperature flame, it has a larger contact area with the flame, allowing for better fire extinguishing performance.

[0019] The combination of nano-hydrophobic silica and silicone oil forms a hydrophobic film, which, together with polyimide fibers, forms a three-dimensional support structure. This structure easily adheres to the three-dimensional surface of the burning object, significantly enhancing mechanical adhesion. Combined with silicon nitride, it enhances the mechanical strength of the material, allowing the extinguishing agent particles to firmly adhere to the three-dimensional burning surface, forming a continuous covering layer with a significant fire extinguishing effect.

[0020] This invention utilizes the hybridization reaction of organosilicon oil and inorganic silicates at high temperatures. Simultaneously, the borate produced by the decomposition of zinc borate fills the gaps in the network, forming a ceramic-like protective layer on the combustion surface. Moreover, its porous structure can adsorb the combustible gases produced by decomposition and suppress deflagration, making it particularly suitable for fighting three-dimensional fires in large oil tank areas.

[0021] This invention ensures that the microparticles remain in the flame area for a longer time, maximizing their fire-extinguishing performance. Furthermore, it exhibits excellent flow properties, is easy to spray, and can quickly extinguish fuel fires without reignition, effectively preventing the spread of fire in areas where fuel has flowed. The invention utilizes advanced production processes and is simple and easy to implement, making it highly valuable for practical applications. Attached Figure Description

[0022] Figure 1 This is a comparison chart of the moisture absorption rate and flowability of the dry powder fire extinguishing agents obtained in Example 5 and Comparative Examples 1-3.

[0023] Figure 2 The diagram shows a comparison of the penetration and electrical insulation properties of the dry powder fire extinguishing agents obtained in Example 5 and Comparative Examples 1-3.

[0024] Figure 3 This is a comparison chart of the extinguishing time of the dry powder extinguishing agents obtained in Example 5 and Comparative Examples 1-3. Detailed Implementation

[0025] The present invention will be further explained below with reference to specific embodiments.

[0026] The nano-hydrophobic silica used below was purchased from Quzhou Mouye Chemical Technology Co., Ltd., and is perfluorinated nano-silica. The chlorinated rubber used below was purchased from Shanghai Moulong Yuteng Chemical Co., Ltd., and its grade is CR-10.

[0027] Example 1 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 100g of 10% sodium silicate solution and 50g of 5% silica sol evenly. Add 30g of aluminum nitrate and adjust the pH of the system to 8-9.5 using 1mol / L sodium hydroxide solution. Stir at 40℃ for 1h. Add 10g of hexadecyltrimethylammonium bromide and sonicate for 10min at a frequency of 40kHz. Transfer to a high-pressure reactor and hydrothermally treat at 170℃ for 5h. Cool to room temperature, filter, vacuum dry, calcine at 300℃ for 10min, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 10g of anhydrite to 60g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 1 hour at a speed of 300r / min. After sieving, the particle size is ≤20μm. Add 250g of potassium sulfate, 80g of sodium bicarbonate, 20g of nano-hydrophobic silica, 20g of chlorinated rubber, and 30g of deionized water and mix and grind for 10 minutes. Then, ultrasonically treat for 10 minutes at a frequency of 40kHz to obtain the preform. S3. Mix 20g of polyimide fiber with a diameter of 0.50±0.05μm and 10g of silicon nitride evenly. Add 10g of silicone oil and 10g of zinc borate and mix evenly. Add 500g of pre-made material and stir evenly. Vacuum sinter at 150℃ for 10min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0028] Example 2 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 300g of sodium silicate solution with a mass fraction of 20% and 150g of silica sol with a mass fraction of 15% evenly. Add 80g of aluminum nitrate to the mixture. Adjust the pH of the system to 8-9.5 using a 2mol / L sodium hydroxide solution. Stir at 50℃ for 2 hours. Add 20g of hexadecyltrimethylammonium bromide and sonicate for 30 minutes at a frequency of 50kHz. Transfer the mixture to a high-pressure reactor and hydrothermally treat at 180℃ for 10 hours. Cool to room temperature, filter, vacuum dry, calcine at 350℃ for 30 minutes, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 30g of anhydrite to 200g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 2 hours at a speed of 500r / min. After sieving, the particle size is ≤20μm. Add 400g of potassium sulfate, 150g of sodium bicarbonate, 40g of nano-hydrophobic silica, 40g of chlorinated rubber, and 50g of deionized water and mix and grind for 30 minutes. Then, ultrasonically treat for 20 minutes at a frequency of 60kHz to obtain the preform. S3. Mix 50g of polyimide fiber with a diameter of 0.50±0.05μm and 20g of silicon nitride evenly. Add 30g of silicone oil and 20g of zinc borate and mix evenly. Add 1000g of pre-made material and stir evenly. Vacuum sinter at 220℃ for 30min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0029] Example 3 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 150g of sodium silicate solution with a mass fraction of 18% and 80g of silica sol with a mass fraction of 12% evenly. Add 40g of aluminum nitrate and adjust the pH of the system to 8-9.5 using a 1.8mol / L sodium hydroxide solution. Stir at 42℃ for 100min. Add 12g of cetyltrimethylammonium bromide and sonicate for 25min at a frequency of 42kHz. Transfer the mixture to a high-pressure reactor and hydrothermally treat at 177℃ for 7h. Cool to room temperature, filter, vacuum dry, calcine at 340℃ for 15min, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 15g of anhydrite to 160g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 100min at a speed of 350r / min. After sieving, the particle size is ≤20μm. Add 360g of potassium sulfate, 100g of sodium bicarbonate, 35g of nano-hydrophobic silica, 25g of chlorinated rubber, and 45g of deionized water and mix and grind for 15min. Then, ultrasonically treat for 18min at a frequency of 45kHz to obtain the preform. S3. Mix 40g of polyimide fiber with a diameter of 0.50±0.05μm and 13g of silicon nitride evenly. Add 25g of silicone oil and 12g of zinc borate and mix evenly. Add 900g of pre-made material and stir evenly. Vacuum sinter at 180℃ for 25min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0030] Example 4 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 250g of sodium silicate solution (12% by mass) and 120g of silica sol (8% by mass) evenly. Add 70g of aluminum nitrate and adjust the pH of the system to 8-9.5 using 1.2mol / L sodium hydroxide solution. Stir at 48℃ for 80min. Add 18g of cetyltrimethylammonium bromide and sonicate for 15min at a frequency of 48kHz. Transfer the mixture to a high-pressure reactor and hydrothermally treat at 173℃ for 9h. Cool to room temperature, filter, vacuum dry, calcine at 320℃ for 25min, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 25g of anhydrite to 100g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 80min at a speed of 450r / min. After sieving, the particle size is ≤20μm. Add 300g of potassium sulfate, 140g of sodium bicarbonate, 25g of nano-hydrophobic silica, 35g of chlorinated rubber, and 35g of deionized water and mix and grind for 25min. Then, ultrasonically treat for 12min at an ultrasonic frequency of 55kHz to obtain the preform. S3. Mix 30g of polyimide fiber with a diameter of 0.50±0.05μm and 17g of silicon nitride evenly. Add 15g of silicone oil and 18g of zinc borate and mix evenly. Add 700g of pre-made material and stir evenly. Vacuum sinter at 200℃ for 15min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0031] Example 5 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 200g of 15% sodium silicate solution and 100g of 10% silica sol evenly. Add 60g of aluminum nitrate and adjust the pH of the system to 8-9.5 using 1.5mol / L sodium hydroxide solution. Stir at 45℃ for 90min. Add 15g of cetyltrimethylammonium bromide and sonicate for 20min at a frequency of 45kHz. Transfer the mixture to a high-pressure reactor and hydrothermally treat at 175℃ for 8h. Cool to room temperature, filter, vacuum dry, calcine at 330℃ for 20min, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 20g of anhydrite to 120g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 90min at a speed of 400r / min. After sieving, the particle size is ≤20μm. Add 330g of potassium sulfate, 120g of sodium bicarbonate, 30g of nano-hydrophobic silica, 30g of chlorinated rubber, and 40g of deionized water and mix and grind for 20min. Then, ultrasonically treat for 15min at a frequency of 50kHz to obtain the preform. S3. Mix 35g of polyimide fiber with a diameter of 0.50±0.05μm and 15g of silicon nitride evenly. Add 20g of silicone oil and 15g of zinc borate and mix evenly. Add 800g of pre-made material and stir evenly. Vacuum sinter at 190℃ for 20min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0032] Comparative Example 1 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 200g of 15% sodium silicate solution and 100g of 10% silica sol evenly. Add 60g of aluminum nitrate and adjust the pH of the system to 8-9.5 using 1.5mol / L sodium hydroxide solution. Stir at 45℃ for 90min. Add 15g of cetyltrimethylammonium bromide and sonicate for 20min at a frequency of 45kHz. Transfer the mixture to a high-pressure reactor and hydrothermally treat at 175℃ for 8h. Cool to room temperature, filter, vacuum dry, calcine at 330℃ for 20min, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 20g of anhydrite to 120g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 90min at a speed of 400r / min. After sieving, the particle size is ≤20μm. Add 330g of potassium sulfate, 120g of sodium bicarbonate, 30g of nano-hydrophobic silica, 30g of chlorinated rubber, and 40g of deionized water and mix and grind for 20min. Then, ultrasonically treat for 15min at a frequency of 50kHz to obtain the preform. S3. Mix 35g of calcium carbonate and 15g of silicon nitride evenly, add 20g of silicone oil and 15g of zinc borate and mix evenly, add 800g of pre-made material and stir evenly, vacuum sinter at 190℃ for 20min, cool naturally to room temperature, pulverize, and sieve using a 15μm sieve.

[0033] Comparative Example 2 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Mix 200g of 15% sodium silicate solution and 100g of 10% silica sol evenly. Add 60g of aluminum nitrate and adjust the pH of the system to 8-9.5 using 1.5mol / L sodium hydroxide solution. Stir at 45℃ for 90min. Add 15g of cetyltrimethylammonium bromide and sonicate for 20min at a frequency of 45kHz. Transfer the mixture to a high-pressure reactor and hydrothermally treat at 175℃ for 8h. Cool to room temperature, filter, vacuum dry, calcine at 330℃ for 20min, cool to room temperature, and pulverize to obtain a porous composite material. S2. Add 20g of potassium sulfate to 120g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 90min at a speed of 400r / min. After sieving, the particle size is ≤20μm. Add 330g of potassium sulfate, 120g of sodium bicarbonate, 30g of nano-hydrophobic silica, 30g of chlorinated rubber, and 40g of deionized water and mix and grind for 20min. Then, ultrasonically treat for 15min at a frequency of 50kHz to obtain the preform. S3. Mix 35g of polyimide fiber with a diameter of 0.50±0.05μm and 15g of silicon nitride evenly. Add 20g of silicone oil and 15g of zinc borate and mix evenly. Add 800g of pre-made material and stir evenly. Vacuum sinter at 190℃ for 20min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0034] Comparative Example 3 A method for preparing a high-efficiency dry powder fire extinguishing agent includes the following steps: S1. Add 60g of aluminum nitrate to 300g of silica sol with a mass fraction of 10%, adjust the pH of the system to 8-9.5 using a 1.5mol / L sodium hydroxide solution, stir at 45℃ for 90min, add 15g of cetyltrimethylammonium bromide, sonicate for 20min at a frequency of 45kHz, transfer to a high-pressure reactor, hydrothermally treat at 175℃ for 8h, cool to room temperature, filter, vacuum dry, calcine at 330℃ for 20min, cool to room temperature, and pulverize to obtain a porous composite material; S2. Add 20g of anhydrite to 120g of porous composite material and mix. Then, put the mixture into a ball mill and ball mill for 90min at a speed of 400r / min. After sieving, the particle size is ≤20μm. Add 330g of potassium sulfate, 120g of sodium bicarbonate, 30g of nano-hydrophobic silica, 30g of chlorinated rubber, and 40g of deionized water and mix and grind for 20min. Then, ultrasonically treat for 15min at a frequency of 50kHz to obtain the preform. S3. Mix 35g of polyimide fiber with a diameter of 0.50±0.05μm and 15g of silicon nitride evenly. Add 20g of silicone oil and 15g of zinc borate and mix evenly. Add 800g of pre-made material and stir evenly. Vacuum sinter at 190℃ for 20min. Allow to cool naturally to room temperature. Crush and sieve using a 15μm sieve.

[0035] The performance of the dry powder fire extinguishing agents obtained in Example 5 and Comparative Examples 1-3 was tested in accordance with GB 4066-2017 "Dry Powder Fire Extinguishing Agents". The bulk density and moisture content of the dry powder fire extinguishing agents obtained in Example 5 and Comparative Examples 1-3 all met the requirements of GB 4066-2017 and showed no significant differences among them. The water repellency test results of all four agents showed no obvious water absorption and no clumping.

[0036] The results of moisture absorption, flowability, penetration, and electrical insulation of the dry powder fire extinguishing agents obtained in Example 5 and Comparative Examples 1-3 are as follows: Figure 1 and Figure 2As shown. The dry powder extinguishing agent obtained in Example 5 had the highest penetration and electrical insulation properties, which were superior to Comparative Examples 1-3 (P<0.05); while the dry powder extinguishing agent obtained in Example 5 had the lowest moisture absorption and flowability, which were not significantly different from Comparative Example 1, and were superior to Comparative Examples 2-3 (P<0.05).

[0037] A comparative fire extinguishing effect experiment was conducted in a relatively enclosed fire extinguishing test space (2m×2m×2.5m). The ambient temperature was 10-30℃, and ventilation and lighting conditions did not affect the free combustion of fuel. The combustion pan in the experiment was a square oil pan with dimensions of 31.64cm x 31.64cm and a height of 16cm, with a bottom area of ​​0.1m². 2 The bottom of the test chamber was lined with water, and the bottom of the oil pan was 22cm above the ground. The fuel used was soybean oil, and the amount used was 3L. First, a certain amount of water was added to the bottom of the oil pan, then the soybean oil was poured into the oil pan, and then it was ignited. The door was opened for pre-ignition for 30 seconds, the door of the test space was closed, and 100g of the dry powder extinguishing agent obtained in Example 5 and Comparative Examples 1-3 was sprayed in. The extinguishing time of each group was recorded.

[0038] like Figure 3 As shown, the dry powder extinguishing agent obtained in Example 5 had the shortest extinguishing time for fuel oil, which was better than that of Comparative Examples 1-3 (P<0.05).

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-efficiency dry powder fire extinguishing agent, characterized in that, Includes the following steps: S1. Mix sodium silicate solution and silica sol evenly, add aluminum nitrate to adjust the pH of the system to 8-9.5, stir at 40-50℃ for 1-2 hours, add hexadecyltrimethylammonium bromide and sonicate for 10-30 minutes, hydrothermally treat at 170-180℃ for 5-10 hours, cool to room temperature, filter, vacuum dry, calcine at 300-350℃ for 10-30 minutes, cool to room temperature, and pulverize to obtain porous composite material; S2. Add hard gypsum to the porous composite material and mix. Ball mill for 1-2 hours, sieve, add potassium sulfate, sodium bicarbonate, nano hydrophobic silica, chlorinated rubber and water, mix and grind for 10-30 minutes, and ultrasonically treat for 10-20 minutes to obtain the preform. S3. Mix polyimide fiber and silicon nitride evenly, add silicone oil and zinc borate and mix evenly, add pre-made material and stir evenly, vacuum sinter at 150-220℃ for 10-30 minutes, cool naturally to room temperature, crush and sieve.

2. The preparation method of the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S1, the mass fraction of sodium silicate solution is 10-20%, the mass fraction of silica sol is 5-15%, and the ratio of sodium silicate solution, silica sol, aluminum nitrate, and hexadecyltrimethylammonium bromide is 10-30:5-15:3-8:1-2.

3. The preparation method of the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S1, the pH of the system is adjusted to 8-9.5 using a sodium hydroxide solution with a concentration of 1-2 mol / L.

4. The preparation method of the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S1, the ultrasonic frequency is 40-50kHz.

5. The preparation method of the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S2, the mass ratio of porous composite material, anhydrite, potassium sulfate, sodium bicarbonate, nano-hydrophobic silica, chlorinated rubber, and water is 6-20:1-3:25-40:8-15:2-4:2-4:3-5.

6. The preparation method of the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S2, the ball milling speed is 300-500 r / min.

7. The preparation method of the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S2, the nano-hydrophobic silica is nano-silica with perfluoroalkyl chains grafted onto its surface.

8. The method for preparing the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S2, the ultrasonic frequency is 40-60kHz.

9. The method for preparing the high-efficiency dry powder fire extinguishing agent according to claim 1, characterized in that, In S3, the diameter of the polyimide fiber is 0.1-1μm, and the mass ratio of polyimide fiber, silicon nitride, silicone oil, zinc borate, and preform is 2-5:1-2:1-3:1-2:50-100.

10. A high-efficiency dry powder fire extinguishing agent, characterized in that, It is prepared by the method described in any one of claims 1-9 for the preparation of high-efficiency dry powder fire extinguishing agent.

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