A solid extinguishing medium - perfluorohexanone - composite extinguishing agent

Abstract

The application discloses a solid extinguishing medium-perfluorohexanone-composite extinguishing agent and relates to the technical field of extinguishing agents. In the preparation of the solid extinguishing medium-perfluorohexanone-composite extinguishing agent, modified aerogel is prepared by using water glass as a silicon source, solvent replacement and hydrophobic modification and normal-pressure drying; the perfluorohexanone is vacuum-adsorbed in the modified aerogel, so that the solid extinguishing medium-perfluorohexanone-composite extinguishing agent is prepared. The solid extinguishing medium-perfluorohexanone-composite extinguishing agent prepared by the application has the advantages of preventing re-ignition and good extinguishing effect.

Description

Technical Field

[0001] This invention relates to the field of fire extinguishing agent technology, specifically to a solid fire extinguishing medium - perfluorohexanone - composite fire extinguishing agent. Background Technology

[0002] Powder extinguishing agents, due to their wide applicability, have become one of the mainstream fire extinguishing media in high-rise buildings, electronic equipment rooms, and other similar locations. Their extinguishing mechanism primarily relies on chemical inhibition and asphyxiation. However, traditional powder extinguishing agents typically lack the ability to reduce the temperature of the flame zone, which to some extent limits their extinguishing effectiveness. Furthermore, these agents exhibit strong corrosiveness and insufficient resistance to reignition. In contrast, perfluorohexanone, as a highly efficient liquid extinguishing agent, has been widely used in total flooding fire suppression systems. However, in open environments, due to its low boiling point, perfluorohexanone readily vaporizes, making it difficult to maintain a liquid phase to penetrate the flame's thermal radiation zone and reach the core of the combustion reaction. A significant amount of the extinguishing agent is lost through vaporization during its migration towards the fire source, resulting in a substantial decrease in its actual extinguishing effect. Summary of the Invention

[0003] The purpose of this invention is to provide a solid fire extinguishing medium—perfluorohexanone—composite fire extinguishing agent, in order to solve the problems existing in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent is prepared by vacuum adsorption of perfluorohexanone in a modified aerogel.

[0005] As an optimization, the modified aerogel is prepared by solvent displacement and hydrophobic modification using water glass as the silicon source, followed by drying at normal pressure.

[0006] As an optimization, the hydrophobic modification was performed using trimethylchlorosilane.

[0007] As an optimization, the modulus of the water glass is 3 to 3.5.

[0008] A method for preparing a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent includes the following preparation steps: (1) First, adjust the pH of the water glass solution to 2-3 with hydrochloric acid, then adjust the pH to 5-5.5 with ammonia solution, seal the gel, age at room temperature, break it up, add anhydrous ethanol, shake in a water bath, filter, add n-hexane, shake in a water bath, filter, add trimethylchlorosilane solution, shake in a water bath, filter, wash, dry, and obtain the modified aerogel. (2) Add the modified aerogel into a pressure-resistant container, evacuate, let stand, close the gas valve, inject perfluorohexanone, seal, stir to adsorb, let stand, release the vacuum and take out to obtain solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent.

[0009] As an optimization, the mass ratio of the water glass solution, anhydrous ethanol, n-hexane, and trimethylchlorosilane solution in step (1) is 1:(2~3):(2~3):(2~3).

[0010] As an optimization, the water glass solution in step (1) is obtained by diluting water glass with water, wherein the mass ratio of water glass to water is 1:(1.5~2).

[0011] As an optimization, the volume ratio of trimethylchlorosilane to n-hexane in the trimethylchlorosilane solution in step (1) is (1.4~1.8):10.

[0012] As an optimization, the temperature of the water bath oscillation in step (1) is 40~50℃.

[0013] As an optimization, the drying in step (1) is performed by drying at 50~60℃, 80~90℃, and 120~130℃ for 3~4 hours respectively.

[0014] As an optimization, the mass ratio of the modified aerogel to perfluorohexanone in step (2) is 1:(0.2~0.3).

[0015] As an optimization, the vacuuming in step (2) needs to reduce the air pressure to below 100 Pa.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent, the present invention first uses water glass as a silicon source, and prepares a modified aerogel by solvent replacement, hydrophobic modification and drying at normal pressure; then, perfluorohexanone is vacuum adsorbed into the modified aerogel to obtain the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent.

[0017] First, using high-modulus water glass as the silicon source, the gel structure network obtained with water glass of a suitable modulus has sufficient strength, and the fine channels are not easily collapsed during the drying process, which is conducive to increasing the specific surface area and pore volume, thereby increasing the loading of perfluorohexanone. After the water glass solution gel ages into a wet gel, it cannot be dried directly to ensure the integrity and connectivity of the internal mesopores and micropores. Due to the high surface tension of water, direct drying will lead to excessive capillary pressure, which will destroy a large number of mesopores, resulting in a decrease in specific surface area and pore volume. Hexane solvent has low surface tension and is more volatile, but water and hexane are immiscible and difficult to directly replace. Therefore, anhydrous ethanol is first added to replace the water in the wet gel, and then hexane is added to replace the anhydrous ethanol, thereby replacing the solvent in the gel network with hexane as much as possible.

[0018] Secondly, after solvent replacement, a hexane solution of trimethylchlorosilane was added to modify the surface of the wet gel. This is because although solvent replacement reduces the capillary pressure encountered during drying, the wet gel still contains a large number of silanol groups. During drying, dehydration and condensation continue, leading to the collapse of mesoporous channels, a decrease in specific surface area and pore volume, and a poorer loading effect on perfluorohexanone. Furthermore, perfluorohexanone is a perfluorinated compound with low surface energy and poor compatibility with hydrophilic silanol groups, resulting in poor loading and adsorption effects. However, modification with trimethylchlorosilane effectively addresses this by covering and consuming the silanol groups in the channels, thus fixing the pore structure and increasing the specific surface area and pore volume. It also transforms the gel surface into a hydrophobic, low-surface-energy structure, allowing for better adsorption and loading of perfluorohexanone, effectively increasing the perfluorohexanone loading capacity. After modification with trimethylchlorosilane, it needs to be dried at atmospheric pressure. The drying process has a significant impact on the formation and fixation of pores and pore structure. If it is dried directly at high temperature, the solvent in the pores will boil and evaporate violently and undergo a phase change into gas. This violent phase change will cause damage and collapse of the pore structure, resulting in a decrease in specific surface area and pore volume. Therefore, it is chosen to dry at low temperature for a certain period of time first and then gradually increase the drying temperature to reduce the damage to the aerogel pores caused by solvent evaporation and phase change while ensuring thorough drying.

[0019] Finally, perfluorohexanone was adsorbed and loaded onto modified aerogel via vacuum adsorption. Perfluorohexanone is a high-performance fire extinguishing agent, but as a liquid extinguishing agent, its low boiling point is both an advantage and a disadvantage. The advantage is that its low boiling point allows it to rapidly vaporize and absorb heat in the fire, lowering the fire temperature and further extinguishing the flames through chemical inhibition, preventing reignition. However, the rapid vaporization phase transition results in significant consumption as it penetrates the core combustion zone, leading to a consumption rate far exceeding the actual effective amount. By adsorbing and loading perfluorohexanone onto modified aerogel, the solid modified aerogel can penetrate the combustion reaction zone and reach the core more quickly than perfluorohexanone, precisely releasing the loaded perfluorohexanone within the core zone, thus maximizing its excellent fire extinguishing performance. Simultaneously, the modified aerogel's excellent temperature resistance and insulation properties, when covering the combustion core, can block heat radiation outwards, synergistically reducing the fire temperature with perfluorohexanone and preventing further thermal runaway. Furthermore, the modified aerogel does not release all of the perfluorohexanone at once when it releases it. Its slow-release properties allow it to continuously release perfluorohexanone after it is sprayed, thereby maintaining the extinguishing concentration of perfluorohexanone in the fire for a long time, and thus reducing and inhibiting the occurrence of reignition. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] The raw material information used in all the following examples and comparative examples is as follows: Water glass: modulus 3.5, Baume degree 35°Bé; Water glass solution: obtained by diluting water glass with water, wherein the mass ratio of water glass to water is 1:2; Trimethylchlorosilane solution: In Example 1, the volume ratio of trimethylchlorosilane to n-hexane in the trimethylchlorosilane solution was 1.8:10; in Example 2, the volume ratio of trimethylchlorosilane to n-hexane in the trimethylchlorosilane solution was 1.6:10; and in Example 3, the volume ratio of trimethylchlorosilane to n-hexane in the trimethylchlorosilane solution was 1.4:10. Hydrochloric acid: concentration 0.1 mol / L; Ammonia solution: concentration 1 mol / L.

[0022] Example 1: A method for preparing a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent, the method comprising the following preparation steps: (1) The mass ratio of water glass solution, anhydrous ethanol, n-hexane and trimethylchlorosilane solution is 1:2:2:2. First, the pH of the water glass solution is adjusted to 2 with hydrochloric acid, and then the pH is adjusted to 5 with ammonia solution. The gel is sealed for 2 hours, aged at room temperature for 8 days, broken, anhydrous ethanol is added, and the mixture is shaken in a water bath at 40°C for 12 hours. After filtration, n-hexane is added, and the mixture is shaken in a water bath at 40°C for 12 hours. After filtration, trimethylchlorosilane solution is added, and the mixture is shaken in a water bath at 40°C for 12 hours. After filtration, the mixture is washed twice with n-hexane and dried at 50°C, 80°C and 120°C for 4 hours respectively to obtain the modified aerogel. (2) The modified aerogel was added to a pressure-resistant container at a mass ratio of 1:0.2 to perfluorohexanone. The container was evacuated to a pressure of less than 100 Pa. After standing for 40 min, the gas valve was closed, perfluorohexanone was injected, the container was sealed, and the container was stirred at 100 r / min for 60 min to adsorb the aerogel. After standing for 10 h, the container was removed from the vacuum to obtain a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent.

[0023] Example 2: A method for preparing a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent, the method comprising the following preparation steps: (1) The mass ratio of water glass solution, anhydrous ethanol, n-hexane and trimethylchlorosilane solution is 1:2.5:2.5:2.5. First, the pH of the water glass solution is adjusted to 2.5 with hydrochloric acid, and then the pH is adjusted to 5.2 with ammonia solution. The gel is sealed for 2.5h, aged at room temperature for 9 days, broken, anhydrous ethanol is added, and the mixture is shaken in a water bath at 45℃ for 11h. After filtration, n-hexane is added, and the mixture is shaken in a water bath at 45℃ for 11h. After filtration, trimethylchlorosilane solution is added, and the mixture is shaken in a water bath at 45℃ for 11h. After filtration, the mixture is washed twice with n-hexane and dried at 55℃, 85℃ and 125℃ for 3.5h respectively to obtain the modified aerogel. (2) The modified aerogel was added to a pressure-resistant container at a mass ratio of 1:0.25 to perfluorohexanone. The container was evacuated to a pressure of less than 100 Pa and allowed to stand for 45 min. The gas valve was closed, perfluorohexanone was injected, the container was sealed, and the container was stirred at 100 r / min for 55 min. The container was allowed to stand for 11 h, and the container was removed from the vacuum to obtain a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent.

[0024] Example 3: A method for preparing a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent, the method comprising the following preparation steps: (1) The mass ratio of water glass solution, anhydrous ethanol, n-hexane and trimethylchlorosilane solution is 1:3:3:3. First, the pH of the water glass solution is adjusted to 3 with hydrochloric acid, and then the pH is adjusted to 5.5 with ammonia solution. The gel is sealed for 3 hours, aged at room temperature for 10 days, broken, anhydrous ethanol is added, and the mixture is shaken in a 50°C water bath for 10 hours. After filtration, n-hexane is added, and the mixture is shaken in a 50°C water bath for 10 hours. After filtration, trimethylchlorosilane solution is added, and the mixture is shaken in a 50°C water bath for 10 hours. After filtration, the mixture is washed 3 times with n-hexane and dried at 60°C, 90°C and 130°C for 3 hours respectively to obtain the modified aerogel. (2) The modified aerogel was added to a pressure-resistant container at a mass ratio of 1:0.3 to perfluorohexanone. The container was evacuated to a pressure of less than 100 Pa and allowed to stand for 50 min. The gas valve was closed, perfluorohexanone was injected, the container was sealed, and the container was stirred at 150 r / min for 50 min. The container was allowed to stand for 12 h, and the vacuum was released to obtain the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent.

[0025] Comparative Example 1: The difference between the preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent in Comparative Example 1 and Example 2 is that the concentration of the trimethylchlorosilane solution used in step (1) is different, wherein the volume ratio of trimethylchlorosilane to n-hexane is 0.4:10. The remaining steps are the same as in Example 2.

[0026] Comparative Example 2: The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent in Comparative Example 2 differs from that in Example 2 in that the concentration of the trimethylchlorosilane solution used in step (1) is different, wherein the volume ratio of trimethylchlorosilane to n-hexane is 0.8:10. The remaining steps are the same as in Example 2.

[0027] Comparative Example 3: The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent in Comparative Example 3 differs from that in Example 2 in that the concentration of the trimethylchlorosilane solution used in step (1) is different, wherein the volume ratio of trimethylchlorosilane to n-hexane is 2.0:10. The remaining steps are the same as in Example 2.

[0028] Comparative Example 4: The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent in Comparative Example 4 differs from that in Example 2 in that the concentration of the trimethylchlorosilane solution used in step (1) is different, wherein the volume ratio of trimethylchlorosilane to n-hexane is 2.4:10. The remaining steps are the same as in Example 2.

[0029] Comparative Example 5: The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent in Comparative Example 5 differs from that in Example 2 in that trimethylchlorosilane solution is not used in step (1), and an equal volume of n-hexane is used instead of trimethylchlorosilane solution. The remaining steps are the same as in Example 2.

[0030] Comparative Example 6: The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent in Comparative Example 6 differs from that in Example 2 in step (1). Step (1) is modified as follows: the mass ratio of water glass solution, anhydrous ethanol, n-hexane, and trimethylchlorosilane solution is 1:2.5:2.5:2.5. First, the pH of the water glass solution is adjusted to 2.5 with hydrochloric acid, and then the pH is adjusted to 5.2 with ammonia solution. The gel is sealed for 2.5 hours, aged at room temperature for 9 days, broken up, anhydrous ethanol is added, and the mixture is shaken in a water bath at 45°C for 11 hours. After filtration, n-hexane is added, and the mixture is shaken in a water bath at 45°C for 11 hours. After filtration, trimethylchlorosilane solution is added, and the mixture is shaken in a water bath at 45°C for 11 hours. After filtration, the mixture is washed twice with n-hexane and dried at 125°C for 10 hours each time to obtain the modified aerogel. The remaining steps are the same as in Example 2.

[0031] Test Example 1: Basic performance testing: The specific surface area of ​​the prepared modified aerogel and the loading rate of perfluorohexanone in the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent were tested to evaluate the perfluorohexanone loading capacity. The specific test method is as follows: Specific surface area: The specific surface area of ​​the prepared modified aerogel was tested in accordance with GB / T 19587-2017. Nitrogen was used as the test gas and the BET multi-point method was used for testing. The specific surface area was calculated according to the calculation formula in the standard. Each group was tested in parallel for 5 times and the average value was recorded. Loading rate: In the adsorption step (2) of each embodiment and comparative example, the mass m1 of the modified aerogel and the mass m2 of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent obtained after adsorption were recorded. The loading rate was calculated by the formula loading rate = (m2-m1)÷m1×100%. Each group was measured in parallel 5 times, and the average value was recorded.

[0032] The results are shown in Table 1; A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-6 in Table 1 reveals that the modified aerogel prepared by the present invention has a high specific surface area and a high loading rate of perfluorohexanone.

[0033] Comparing the data in the table, Comparative Examples 1-5 demonstrate that trimethylchlorosilane effectively improves the specific surface area and perfluorohexanone loading rate of the aerogel. When the amount of trimethylchlorosilane used is too low, the high content of residual silanols leads to continued dehydration and condensation during drying, resulting in damage to the pore structure of the gel. When the amount of trimethylchlorosilane used is too high, excessive trimethylchlorosilane reacts violently with the residual silanols, causing the gel skeleton to collapse, which in turn leads to a decrease in specific surface area and a low perfluorohexanone loading rate. When no trimethylchlorosilane modification is performed, the strong hydrophilicity of the surface silanols results in poor compatibility with perfluorohexanone, leading to poor adsorption. Although the specific surface area is high, the perfluorohexanone loading rate is low.

[0034] By comparing the data in the table, the data in Comparative Example 6 shows that the gradient heating drying method makes the drying process more gentle, avoiding the collapse of the gel pore structure caused by direct high-temperature drying, which in turn leads to a decrease in specific surface area and a decrease in perfluorohexanone loading.

[0035] Test Example 2: Fire extinguishing performance test: The fire extinguishing performance of the prepared solid fire extinguishing medium - perfluorohexanone - composite fire extinguishing agent was evaluated by testing the extinguishing time and reignition situation of lithium battery thermal runaway fire. The specific test method is as follows: Fire extinguisher filling: Using a 500g portable fire extinguisher, weigh 500g of the prepared solid fire extinguishing medium - perfluorohexanone - composite fire extinguishing agent, pour it into the fire extinguisher using a funnel, and fill it using a nitrogen filling machine at a filling pressure of 1.2MPa to obtain the sample fire extinguisher. Fire extinguishing test platform: Using 18650 battery modules, containing 52 individual cells, each cell is 18mm in diameter, 65mm in height, with a capacity of 2.5Ah and a state of charge of 70%. There are 2 modules, placed on a 20cm high support, with a 30cm×30cm×5cm oil pool placed below. The oil pool contains 800ml of gasoline as an external combustion heat source. This device is placed in a 110cm×65cm×130cm combustion chamber, which is equipped with a viewing window, fire extinguishing agent nozzle, and temperature sensor.

[0036] Fire extinguishing test procedure: First, ignite the gasoline. After the battery module experiences thermal runaway, extinguish the open flame in the oil tank first, then extinguish the jet fire caused by the battery module. Stop spraying after the open flame disappears. Record the time from when the fire extinguisher starts spraying to when the open flame is extinguished as the extinguishing time. After the open flame is extinguished, continue to observe for 2 hours to see if it reignites. Record the reignition situation.

[0037] The results are shown in Table 2; A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-6 in Table 2 reveals that the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent prepared by the present invention has good fire extinguishing performance and no reignition.

[0038] By comparing the data in the table, the data from Comparative Examples 1 to 6 show that when the perfluorohexanone load is high, it can extinguish fires quickly and continuously release perfluorohexanone gas to maintain the extinguishing concentration, thereby reducing the possibility of reignition.

[0039] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent, characterized in that, The solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent is prepared by vacuum adsorption of perfluorohexanone in modified aerogel; The modified aerogel was prepared by solvent displacement and hydrophobic modification using water glass as the silicon source, followed by drying at normal pressure.

2. The solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 1, characterized in that, The hydrophobic modification was performed using trimethylchlorosilane.

3. The solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 1, characterized in that, The modulus of the water glass is 3 to 3.

5.

4. A method for preparing a solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent, characterized in that, The preparation steps include the following: (1) First, adjust the pH of the water glass solution to 2-3 with hydrochloric acid, then adjust the pH to 5-5.5 with ammonia solution, seal the gel, age at room temperature, break it up, add anhydrous ethanol, shake in a water bath, filter, add n-hexane, shake in a water bath, filter, add trimethylchlorosilane solution, shake in a water bath, filter, wash, dry, and obtain the modified aerogel. (2) Add the modified aerogel into a pressure-resistant container, evacuate, let stand, close the gas valve, inject perfluorohexanone, seal, stir to adsorb, let stand, release the vacuum and take out to obtain solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent.

5. The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 4, characterized in that, The mass ratio of the water glass solution, anhydrous ethanol, n-hexane, and trimethylchlorosilane solution in step (1) is 1:(2~3):(2~3):(2~3).

6. The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 4, characterized in that, The water glass solution in step (1) is obtained by diluting water glass with water.

7. The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 4, characterized in that, The temperature of the water bath oscillation in step (1) is 40~50℃.

8. The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 4, characterized in that, The drying in step (1) is to dry at 50~60℃, 80~90℃, and 120~130℃ for 3~4 hours respectively.

9. The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 4, characterized in that, The mass ratio of the modified aerogel to perfluorohexanone in step (2) is 1:(0.2~0.3).

10. The preparation method of the solid fire extinguishing medium-perfluorohexanone-composite fire extinguishing agent according to claim 4, characterized in that, The vacuuming process in step (2) requires reducing the air pressure to below 100 Pa.

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