Aerogel dry water fire extinguishing agent and preparation method and application thereof

Abstract

The application discloses an aerogel dry water fire extinguishing agent and a preparation method and application thereof, and specifically relates to the following steps: preparing SiO2 gel; preparing salt-containing SiO2 slurry; performing solid-liquid separation to obtain gel filter cake; washing part of the gel filter cake with pure water to obtain hydrophilic SiO2 wet gel, mixing a dry water base with the hydrophilic SiO2 wet gel to obtain a dry water mixture; modifying the remaining gel filter cake to obtain hydrophobic SiO2 aerogel; and placing the dry water mixture, a surfactant and the hydrophobic SiO2 aerogel in a high-speed dispersion machine stirring container to perform high-speed stirring, thereby obtaining the aerogel dry water fire extinguishing agent. In the application, the aerogel is used to replace other hydrophobic powders, the aerogel itself has good heat insulation and flame retardant properties, and compared with the currently commonly used strong hydrophobic nanoparticles in the preparation of dry water, the prepared fire extinguishing agent has more excellent fire extinguishing effect.

Description

Technical Field

[0001] This invention relates to the field of fire extinguishing materials technology, specifically to an aerogel dry water fire extinguishing agent, its preparation method, and its application. Background Technology

[0002] Dry water is a core-shell structured dry powder material composed of highly hydrophobic nanoparticles encapsulating tiny liquid droplets. It appears as a fluffy solid powder, but its main component is liquid, with liquid accounting for over 90%. Due to its high hydrophobicity and high water content while retaining the appearance of a solid powder, dry water has been applied in firefighting in recent years, such as the dry water extinguishing agents described in references 1-4.

[0003] Reference 1: Chinese patent document with publication number CN110433443A.

[0004] Reference 1 describes a method for preparing a silica gel-based dry water material and its application as a fire extinguishing agent: Inexpensive industrial water glass is selected as the silicon source. After passing through a strong acid cation exchange resin chromatography column, the pH is adjusted to 6-7 with alkali. Then, before gelation, it is mixed with hydrophobic nanoparticles and stirred in a high-speed stirrer. After stirring, it is allowed to stand for 20-30 minutes to obtain the silica gel-based dry water material.

[0005] Reference 2: Chinese patent document with publication number CN113069707A.

[0006] Reference 2 describes a method for preparing a gel-based dry water extinguishing agent for lithium battery fires: gellan gum, gelatin, carrageenan, agar, and polyvinyl alcohol are added to deionized water and stirred to obtain a mixed sol solution; the mixed sol solution is mixed evenly with a water glass solution; a concentrated strong acid solution is slowly added dropwise to the evenly mixed solution to make its pH reach 7-9, forming a hydrogel; the hydrogel is broken up, and hydrophobic silica and the broken hydrogel are added to a stirrer and stirred to obtain a gel-based dry water extinguishing agent.

[0007] Reference 3: Chinese patent document with publication number CN117717747A.

[0008] Reference 3 describes a dry water extinguishing agent and its preparation method: an insoluble extinguishing core material is mixed with a hydrophobic shell material and then stirred at high speed to obtain a dry water extinguishing agent; the insoluble extinguishing core material is an insoluble iron salt suspension, an insoluble iron salt emulsion, or an insoluble iron salt gel; the high-speed stirring speed is 4000-8000 r / min, and the high-speed stirring time is 1-6 min.

[0009] Reference 4: Chinese patent document with publication number CN112206457A.

[0010] Reference 4 describes a biomass gel-based dry water powder fire extinguishing agent and its preparation method. Its components, by mass percentage, are: 5%–10% hydrophobic solid particles, 0.1%–1.0% aqueous matrix, 0.5%–2.0% gelling agent, and the balance being water. The fire extinguishing agent of this invention exhibits high stability, excellent fire extinguishing efficiency, and is environmentally friendly. Compared with ordinary dry water fire extinguishing agents, this fire extinguishing agent adds a gelling agent and aqueous matrix to a water-based mixture, transforming the internal solution into a gel through their reaction. This significantly improves its pressure resistance and water retention, and has broad application prospects. Summary of the Invention

[0011] The purpose of this invention is to enrich the technical routes of dry water extinguishing agents and to provide an aerogel dry water extinguishing agent, its preparation method, and its application.

[0012] To address the shortcomings of the aforementioned technical problems, the present invention provides a method for preparing an aerogel dry water extinguishing agent, comprising the following steps:

[0013] S1. Add the silicon source to pure water and mix well to obtain solution A;

[0014] S2. Add acid solution to solution A and mix well to obtain solution B. Control the pH of solution B to 1-6.5 and the temperature to 20-55℃ for 0.2-6h. After the reaction is completed, add alkaline solution dropwise, control the pH of solution to 7.5-10.5 and the temperature to 20-55℃ for 0.1-5h. After the reaction is completed, allow it to stand and gel to obtain SiO2 gel.

[0015] S3. After aging the SiO2 gel at a temperature of 25-50℃, a salt-containing SiO2 slurry is obtained.

[0016] S4. The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake;

[0017] S5. Part of the gel filter cake is washed with pure water to obtain hydrophilic SiO2 wet gel. The dry water matrix is ​​mixed with the hydrophilic SiO2 wet gel to obtain a dry water mixture.

[0018] S6. The remaining gel filter cake is mixed with the hydrophobic modifier and reacted at 40-60℃ for 0.5-24h. After supercritical CO2 drying, hydrophobic SiO2 aerogel powder is obtained.

[0019] S7. Place the dry water mixture, surfactant, and hydrophobic SiO2 aerogel powder into a high-speed disperser mixing container and stir at high speed to obtain the aerogel dry water fire extinguishing agent.

[0020] As a further optimization of the preparation method of the aerogel dry water extinguishing agent of the present invention: the silicon source is one or more of sodium silicate, potassium silicate, orthosilicic acid and silica sol, and the molar concentration of silicon source in the mixed solution of silicon source and water is 0.1 to 10 mol / L.

[0021] As a further optimization of the preparation method of the aerogel dry water extinguishing agent of the present invention: the acid solution is one or more of sulfuric acid solution, nitric acid solution or hydrochloric acid solution; the alkaline solution is one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution or ammonia water.

[0022] As a further optimization of the preparation method of the aerogel dry water extinguishing agent of the present invention: in step S4, the dry water matrix is ​​an aqueous solution of sodium chloride or an aqueous solution of ammonium dihydrogen phosphate, the concentration of sodium chloride solution is 5-26.5%, and the concentration of ammonium dihydrogen phosphate solution is 5-10%; the mass ratio of dry water matrix to hydrophilic SiO2 wet gel is 3-5:1.

[0023] As a further optimization of the preparation method of the aerogel dry water fire extinguishing agent of the present invention: the hydrophobic modifier in step S5 is one or more of trimethylchlorosilane (TMCS), methyltrimethoxysilane (MTMS), hexamethyldisilazane (HMDZ) or trimethylethoxysilane (TMES); the mass ratio of hydrophobic modifier to silicon source is 2 to 8:20.

[0024] As a further optimization of the preparation method of the aerogel dry water extinguishing agent of the present invention: the mass ratio of the dry water mixture, surfactant and hydrophobic SiO2 aerogel in step S6 is 100:1~5:10~30.

[0025] As a further optimization of the preparation method of the aerogel dry water extinguishing agent of the present invention: the surfactant in step S6 is polyethylene glycol octylphenyl ether or sodium dodecylbenzenesulfonate.

[0026] The present invention also provides an aerogel dry water extinguishing agent, which is obtained by the above preparation method. The aerogel dry water extinguishing agent is a gel dry water droplet wrapped by hydrophobic aerogel powder and is in the form of fine particles.

[0027] The present invention also provides the application of the above-mentioned aerogel dry water extinguishing agent in the preparation of fire extinguishing patches: the porous material is immersed in the extinguishing agent, so that the extinguishing agent particles are immersed into the pores of the porous material to obtain the extinguishing material, the extinguishing material is coated on the temperature-controlled pyrolysis film, and the fire extinguishing patch is obtained by encapsulation and cutting.

[0028] The porous material is an inorganic material, an inorganic material modified with organic material surface, or an organic-inorganic hybrid material, and the particle size of the porous material is 100-400 μm.

[0029] The temperature-controlled pyrolysis membrane is a phenolic resin film, an epoxy resin film, a polystyrene film, or a polybutyl acrylate film.

[0030] The present invention has the following beneficial effects:

[0031] 1. This invention uses aerogel instead of other hydrophobic powders. Aerogel itself has good heat insulation and flame retardancy. Compared with the strongly hydrophobic nanoparticles commonly used to prepare dry water, the resulting fire extinguishing agent has a better fire extinguishing effect.

[0032] 2. The present invention incorporates a portion of wet gel into the dry water matrix to support the dry water extinguishing agent particles, which can significantly improve the pressure resistance of the dry water extinguishing agent, so that it will not produce a large amount of structural damage when it agglomerates. This can effectively ensure the fire extinguishing efficiency of the dry water extinguishing agent during use.

[0033] 3. In the preparation of aerogel, this invention omits the washing process, allowing the sodium bicarbonate gel product to remain in the finished product. On one hand, sodium bicarbonate decomposes into water and carbon dioxide at high temperatures, simultaneously absorbing heat from the surrounding environment and lowering the temperature below the auto-ignition point of the combustible material, thus achieving a fire extinguishing effect. On the other hand, the carbon dioxide produced by the decomposition of sodium bicarbonate can dilute oxygen, further inhibiting combustion.

[0034] 4. The thickness of the fire extinguishing patch of this invention can be customized, making it suitable for fire extinguishing in confined spaces; the shape can be customized, making it suitable for various flat, curved, and even irregularly shaped surfaces; no signal control is required, and the release of the extinguishing agent is triggered by ambient temperature, avoiding failures caused by sensor or circuit problems; the fire extinguishing patch is attached to the area to be protected, and can release the extinguishing agent immediately when a fire breaks out to achieve the fire extinguishing effect; the fire extinguishing patch has a long lifespan, is easy to maintain, and the extinguishing agent can remain unreleased for a long time when there is no fire. Attached Figure Description

[0035] Figure 1 A photograph of the hydrophilic SiO2 wet gel prepared in Example 1;

[0036] Figure 2 The image shows the actual product of the aerogel dry water extinguishing agent prepared in Example 1.

[0037] Figure 3 A physical image of the aerogel dry water extinguishing agent prepared for Comparative Example 1;

[0038] Figure 4 The particle size distribution diagram of the aerogel dry water extinguishing agent prepared in Example 1;

[0039] Figure 5 The particle size distribution diagram of the aerogel dry water extinguishing agent prepared for Comparative Example 1 is shown. Detailed Implementation

[0040] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0041] <Aerogel dry water extinguishing agent>

[0042] The preparation method of aerogel dry water extinguishing agent includes the following steps:

[0043] A method for preparing an aerogel dry water extinguishing agent includes the following steps:

[0044] S1. Add the silicon source to pure water and mix well to obtain solution A;

[0045] The silicon source is one or more of sodium silicate, potassium silicate, orthosilicic acid and silica sol, and the molar concentration of the silicon source is 0.1 to 10 mol / L.

[0046] S2. Add an acid solution (0.2-0.5 mol / L) to solution A and mix well to obtain solution B. Control the pH of solution B to 1-6.5 and the temperature to 20-55℃ for 0.2-6 h. After the reaction is completed, add an alkaline solution (0.2-0.5 mol / L) dropwise, control the pH of the solution to 7.5-10.5 and the temperature to 20-55℃ for 0.1-5 h. After the reaction is completed, allow it to stand and gel to obtain SiO2 gel.

[0047] The acid solution is one or more of sulfuric acid solution, nitric acid solution, or hydrochloric acid solution; the alkaline solution is one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution, or ammonia solution.

[0048] S3. After aging the SiO2 gel at a temperature of 25-50℃, a salt-containing SiO2 slurry is obtained.

[0049] S4. The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake.

[0050] S5. Part of the gel filter cake is washed with pure water to obtain a hydrophilic SiO2 wet gel. The dry water matrix is ​​mixed with the hydrophilic SiO2 wet gel to obtain a dry water mixture.

[0051] The dry aqueous matrix is ​​an aqueous solution of sodium chloride or ammonium dihydrogen phosphate, with a sodium chloride solution concentration of 5–26.5% and an ammonium dihydrogen phosphate solution concentration of 5–10%. The mass ratio of the dry aqueous matrix to the hydrophilic SiO2 wet gel is 3–5:1.

[0052] Dry water is a core-shell structured dry powder material composed of strongly hydrophobic nanoparticles encapsulating tiny liquid droplets. It appears as a fluffy solid powder, but its main component is actually liquid, with liquid accounting for more than 90%.

[0053] S6. The remaining gel filter cake is mixed with a hydrophobic modifier and reacted at 40-60℃ for 0.5-24h. After supercritical CO2 drying, hydrophobic SiO2 aerogel powder is obtained.

[0054] The hydrophobic modifier is one or more of trimethylchlorosilane (TMCS), methyltrimethoxysilane (MTMS), hexamethyldisilazane (HMDZ) or trimethylethoxysilane (TMES); the mass ratio of the hydrophobic modifier to the silicon source is 2 to 8:20.

[0055] S7. Place the dry water mixture, surfactant, and hydrophobic SiO2 aerogel powder into a high-speed disperser mixing container and stir at high speed (stirring speed 5000-8000 r / min, stirring time 5-10 min) to obtain the aerogel dry water extinguishing agent. The aerogel dry water extinguishing agent is a gel dry water droplet wrapped with hydrophobic aerogel powder and is in the form of fine particles.

[0056] The mass ratio of the dry water mixture, surfactant, and hydrophobic SiO2 aerogel is 100:1~5:10~30.

[0057] This invention uses aerogel instead of other hydrophobic powders. Aerogel itself has good heat insulation and flame retardancy. Compared with the strongly hydrophobic nanoparticles commonly used to prepare dry water, the resulting fire extinguishing agent has a better fire extinguishing effect.

[0058] Incorporating a portion of wet gel into the dry water matrix to support the dry water extinguishing agent particles can significantly improve the pressure resistance of the dry water extinguishing agent, preventing significant structural damage during agglomeration. This effectively ensures the extinguishing efficiency of the dry water extinguishing agent during use.

[0059] In the preparation of aerogel, the washing process is omitted, allowing the sodium bicarbonate product to remain in the finished product. On one hand, sodium bicarbonate decomposes into water and carbon dioxide at high temperatures, absorbing heat from the surrounding environment and lowering the temperature below the auto-ignition point of the combustible material, thus achieving a fire extinguishing effect. On the other hand, the carbon dioxide produced by the decomposition of sodium bicarbonate can dilute oxygen, further inhibiting combustion.

[0060] Fire extinguishing patches

[0061] The preparation method of the fire extinguishing patch includes the following steps:

[0062] Step 1: Immerse the porous material in the extinguishing agent, allowing the extinguishing agent particles to penetrate into the pores of the porous material.

[0063] The porous material is an inorganic material, an organically modified inorganic material, or an organic-inorganic hybrid material, with a particle size of 100–400 μm. Inorganic materials include, but are not limited to, molecular sieves, aerogels, diatomaceous earth, and foam ceramics; organically modified inorganic materials include, but are not limited to, the aforementioned surface-modified inorganic materials; organic-inorganic hybrid materials include, but are not limited to, MOF materials and COF materials. The temperature-controlled pyrolysis membrane is a phenolic resin film, epoxy resin film, polystyrene film, or polybutylene acrylate film.

[0064] Step 2: Apply the fire extinguishing material to the temperature-controlled pyrolysis membrane to a certain thickness.

[0065] The temperature-controlled pyrolysis membrane is a phenolic resin film, an epoxy resin film, a polystyrene film, or a polybutyl acrylate film.

[0066] The specific application process can be either coating or roller coating, and the coating thickness of the fire extinguishing material is 0.1-10cm.

[0067] Step 3: Package and cut the material from Step 2 to obtain the fire extinguishing patch.

[0068] This fire extinguishing patch has the following advantages:

[0069] 1. Thickness can be customized, making it especially suitable for fire extinguishing in confined spaces;

[0070] 2. The shape can be customized and is suitable for various flat, curved, and even irregularly shaped surfaces.

[0071] Lithium-ion batteries used in new energy vehicles and energy storage are prone to thermal runaway and subsequent combustion. Traditional fire suppression methods involve placing a fire suppression module within the battery pack, filled with extinguishing agent. When a thermal runaway signal is detected, the module opens to release the extinguishing agent. However, this approach has several drawbacks: 1. The process from detecting a thermal runaway signal to the extinguishing agent module releasing the agent involves signal transmission and control. Failures in any sensor or signal circuitry during this process can cause the fire suppression module to malfunction, either resulting in a false alarm and wasted extinguishing agent, or failing to open during thermal runaway. 2. Even if sensors and circuitry function normally during thermal runaway, allowing for effective signal transmission and extinguishing agent release, the extinguishing agent module may be far from the location of the thermal runaway. The extinguishing agent may not be able to reach the runaway area in time, or even be blocked by the combustion airflow during the runaway.

[0072] The fire extinguishing patch of this invention has a customizable thickness, making it suitable for fire extinguishing in confined spaces; its shape is also customizable, suitable for various flat, curved, and even irregularly shaped surfaces; it requires no signal control, as the release of the extinguishing agent is triggered by ambient temperature, avoiding failures caused by sensor or wiring problems; the fire extinguishing patch is attached to the area to be protected, and can release the extinguishing agent immediately upon the occurrence of a fire to achieve the desired extinguishing effect; the fire extinguishing patch has a long lifespan, is easy to maintain, and the extinguishing agent can remain unreleased for a long time when there is no fire.

[0073] <Example 1>

[0074] Sodium silicate is mixed with water to obtain solution A, with a molar concentration of sodium silicate of 1 mol / L.

[0075] Sulfuric acid solution (0.3 mol / L) was added to solution A and mixed to obtain solution B. The pH of solution B was controlled at 4.0 and the temperature was 40℃ for 3 hours. After the reaction was completed, sodium hydroxide solution (0.3 mol / L) was added dropwise, and the pH of the solution was controlled at 8.5 and the temperature was 35℃ for 3 hours. After the reaction was completed, SiO2 gel was obtained after static gelation.

[0076] The SiO2 gel was aged at 35°C to obtain a salt-containing SiO2 slurry.

[0077] The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake.

[0078] One-third of the gel filter cake was washed with pure water to obtain a hydrophilic SiO2 wet gel (see actual photo of the hydrophilic SiO2 wet gel). Figure 1 As shown in the figure, a sodium chloride aqueous solution (concentration of 20%) was mixed with a hydrophilic SiO2 wet gel at a mass ratio of 4:1 to obtain a dry water mixture.

[0079] The remaining gel filter cake was mixed with trimethylchlorosilane and reacted at 50°C for 12 h. After supercritical CO2 drying, hydrophobic SiO2 aerogel was obtained.

[0080] A dry water mixture, polyethylene glycol octylphenyl ether, and hydrophobic SiO2 aerogel were placed in a high-speed disperser mixing container and stirred at high speed in a mass ratio of 100:2:20 to obtain the aerogel dry water fire extinguishing agent (see actual photos of the aerogel dry water fire extinguishing agent as shown). Figure 2 (As shown).

[0081] Figure 4 The particle size distribution of the prepared aerogel dry water extinguishing agent is shown in the figure. D10: 13.21 μm; D50: 34.87 μm; D90: 89.99 μm; D95: 109.91 μm; D97: 123.96 μm; average particle size 44.73 μm.

[0082] <Example 2>

[0083] Solution A is obtained by mixing orthosilicic acid with water, and the molar concentration of orthosilicic acid is 0.1 mol / L.

[0084] Nitric acid solution (0.2 mol / L) was added to solution A and mixed to obtain solution B. The pH of solution B was controlled at 1.0 and the temperature was 55℃ for 0.1 h. After the reaction was completed, potassium hydroxide solution (0.5 mol / L) was added dropwise, and the pH of the solution was controlled at 10.5 and the temperature was 20℃ for 0.1 h. After the reaction was completed, SiO2 gel was obtained after static gelation.

[0085] The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake.

[0086] Take 1 / 3 of the gel filter cake and wash it with pure water to obtain a hydrophilic SiO2 wet gel. Mix the hydrophilic SiO2 wet gel with a sodium chloride aqueous solution (concentration of 10.5%) at a mass ratio of 3:1 to obtain a dry water mixture.

[0087] The remaining gel filter cake was mixed with methyltrimethoxysilane and reacted at 40°C for 20 h. After supercritical CO2 drying, hydrophobic SiO2 aerogel was obtained.

[0088] The dry water mixture, sodium dodecylbenzenesulfonate, and hydrophobic SiO2 aerogel are placed in a high-speed disperser mixing container at a mass ratio of 100:1:30 and stirred at high speed to obtain the aerogel dry water fire extinguishing agent.

[0089] <Example 3>

[0090] Solution A is obtained by mixing silica sol with water, and the molar concentration of sodium silicate is 10 mol / L.

[0091] Hydrochloric acid solution (0.5 mol / L) was added to solution A and mixed to obtain solution B. The pH of solution B was controlled at 6.5 and the temperature was 20℃ for 6 h. After the reaction was completed, calcium hydroxide solution (0.2 mol / L) was added dropwise, and the pH of the solution was controlled at 7.5 and the temperature was 55℃ for 5 h. After the reaction was completed, SiO2 gel was obtained after static gelation.

[0092] The SiO2 gel was aged at 35°C to obtain a salt-containing SiO2 slurry.

[0093] The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake.

[0094] Take 1 / 3 of the gel filter cake and wash it with pure water to obtain a hydrophilic SiO2 wet gel. Mix the hydrophilic SiO2 wet gel with an aqueous solution of ammonium dihydrogen phosphate (concentration of 6.5%) at a mass ratio of 3.54:1 to obtain a dry water mixture.

[0095] The remaining gel filter cake was mixed with hexamethyldisilazane and reacted at 60°C for 2 hours. After supercritical CO2 drying, hydrophobic SiO2 aerogel was obtained.

[0096] The dry water mixture of sodium dodecylbenzenesulfonate and hydrophobic SiO2 aerogel are placed in a high-speed disperser mixing container and stirred at high speed in a mass ratio of 100:5:10 to obtain the aerogel dry water fire extinguishing agent.

[0097] <Example 4>

[0098] Diatomaceous earth (particle size 300 μm) was immersed in the fire extinguishing agent prepared in Example 1, so that the fire extinguishing agent particles were immersed into the pores of the porous material to obtain the fire extinguishing material.

[0099] The fire extinguishing material is coated onto a temperature-controlled pyrolysis membrane (phenolic resin film) to a certain thickness.

[0100] Fire extinguishing patches are obtained by packaging and cutting.

[0101] <Example 5>

[0102] Diatomaceous earth (particle size 100μm) was immersed in the fire extinguishing agent prepared in Example 2, so that the fire extinguishing agent particles were immersed into the pores of the porous material to obtain the fire extinguishing material.

[0103] The fire extinguishing material is coated onto a temperature-controlled pyrolysis membrane (epoxy resin film) to a certain thickness.

[0104] Fire extinguishing patches are obtained by packaging and cutting.

[0105] <Example 6>

[0106] Diatomaceous earth (particle size 400 μm) was immersed in the fire extinguishing agent prepared in Example 3, so that the fire extinguishing agent particles were immersed into the pores of the porous material to obtain the fire extinguishing material.

[0107] The fire extinguishing material is coated onto a temperature-controlled pyrolysis membrane (polystyrene film) to a certain thickness.

[0108] Fire extinguishing patches are obtained by packaging and cutting.

[0109] <Comparative Example 1>

[0110] Sodium silicate was mixed with water (sodium silicate molar concentration was 1 mol / L) and pumped into a high-pressure carbonization reaction aging vessel. High-pressure carbon dioxide was injected into the reaction aging vessel. The temperature of the high-pressure carbonization reaction aging vessel was controlled at 50℃, the stirring speed was 800 rpm, the carbon dioxide pressure was 10 MPa, and the reaction time was 30 min to obtain SiO2 gel.

[0111] The temperature inside the high-pressure carbonization reaction aging vessel is controlled at 60℃ and the carbon dioxide pressure is 10MPa for aging and solidification for 2 hours. Then the pressure inside the vessel is released to obtain a salt-containing SiO2 slurry.

[0112] The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake.

[0113] Prepare an aqueous solution of sodium chloride (concentration of 20%) to obtain a dry water matrix.

[0114] The gel filter cake was mixed with trimethylchlorosilane and reacted at 50°C for 12 h. After supercritical CO2 drying, hydrophobic SiO2 aerogel was obtained.

[0115] The dry water matrix, surfactant, and hydrophobic SiO2 aerogel were placed in a high-speed disperser mixing container at a mass ratio of 100:2:20 and stirred at high speed to obtain the aerogel dry water fire extinguishing agent (actual product photo as shown). Figure 3 (As shown).

[0116] Figure 5 The particle size distribution of the aerogel dry water extinguishing agent was obtained as follows: D10: 30.32 μm; D50: 66.67 μm; D90: 132.19 μm; D95: 153.35 μm; D97: 166.55 μm; average particle size 74.69 μm.

[0117] Performance Testing

[0118] Loose density test:

[0119] Weigh 50g of powder sample, accurate to 0.2g, and place it in a stoppered graduated cylinder. Invert the graduated cylinder 10 times at a rate of 2s per cycle. Then, let the stoppered graduated cylinder stand vertically to the horizontal plane for 3 minutes, record the sample volume, and calculate the bulk density D according to the formula D=m / V and record it. Perform the experiment 3 times and take the average value.

[0120] Pressure resistance test:

[0121] The pressure resistance of dry-water extinguishing agents was evaluated using the high-pressure breakage rate. Prepared dry-water extinguishing agents were sieved into particle sizes of 50–100 μm, 100–150 μm, and 150–250 μm. 5 g samples were weighed from each particle size range and added to a high-pressure reactor. The reactor was pressurized to 1.2 MPa with nitrogen and pressurized for 5 minutes before depressurization. The pressurized samples were then sieved through a sieve corresponding to their original particle size. Any change in particle size was considered a breakage. The breakage amount within each range was recorded, and the breakage rates were summed to obtain the total breakage rate. Each extinguishing agent was tested three times.

[0122] This shows that, under the same pressure conditions, the breakage rate of dry water extinguishing agents with added wet gel is significantly lower than that of dry water without wet gel. The addition of wet gel improves the pressure resistance of the dry water powder. This is because colloidal particles in the solution will connect with each other under certain conditions to form a spatial network structure. The voids in the structure are filled with liquid as a dispersion medium. Under high pressure, the spatial skeleton formed enhances the structural strength of the dry water material, and the core-shell structure is more stable. Under high pressure, it will not produce a large amount of structural damage, thus effectively ensuring the extinguishing efficiency of the dry water extinguishing agent during use.

[0123] The experimental results on the breakage rate show that the breakage rate increases significantly when the particle size exceeds 150 μm.

[0124] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing an aerogel dry water extinguishing agent, characterized in that: Includes the following steps: S1. Add the silicon source to pure water and mix well to obtain solution A; S2. Add acid solution to solution A and mix well to obtain solution B. Control the pH of solution B to 1-6.5 and the temperature to 20-55℃ for 0.2-6h. After the reaction is completed, add alkaline solution dropwise, control the pH of solution to 7.5-10.5 and the temperature to 20-55℃ for 0.1-5h. After the reaction is completed, allow it to stand and gel to obtain SiO2 gel. S3. After aging the SiO2 gel at a temperature of 25-50℃, a salt-containing SiO2 slurry is obtained. S4. The salt-containing silica slurry is transferred to a vacuum filter washing machine for solid-liquid separation to obtain a gel filter cake; S5. Part of the gel filter cake is washed with pure water to obtain hydrophilic SiO2 wet gel. The dry water matrix is ​​mixed with the hydrophilic SiO2 wet gel to obtain a dry water mixture. S6. The remaining gel filter cake is mixed with the hydrophobic modifier and reacted at 40-60℃ for 0.5-24h. After supercritical CO2 drying, hydrophobic SiO2 aerogel powder is obtained. S7. Place the dry water mixture, surfactant, and hydrophobic SiO2 aerogel powder into a high-speed disperser mixing container and stir at high speed to obtain the aerogel dry water fire extinguishing agent.

2. The preparation method of the aerogel dry water extinguishing agent as described in claim 1, characterized in that: The silicon source is one or more of sodium silicate, potassium silicate, orthosilicic acid and silica sol, and the molar concentration of the silicon source in the mixed solution of silicon source and water is 0.1 to 10 mol / L.

3. The preparation method of the aerogel dry water extinguishing agent as described in claim 1, characterized in that: The acid solution is one or more of sulfuric acid solution, nitric acid solution or hydrochloric acid solution; the alkaline solution is one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution or ammonia solution.

4. The preparation method of the aerogel dry water extinguishing agent as described in claim 1, characterized in that: In step S5, the dry aqueous matrix is ​​an aqueous solution of sodium chloride or an aqueous solution of ammonium dihydrogen phosphate, with a sodium chloride solution concentration of 5-26.5% and an ammonium dihydrogen phosphate solution concentration of 5-10%; the mass ratio of the dry aqueous matrix to the hydrophilic SiO2 wet gel is 3-5:

1.

5. The preparation method of the aerogel dry water extinguishing agent as described in claim 1, characterized in that: In step S6, the hydrophobic modifier is one or more of trimethylchlorosilane TMCS, methyltrimethoxysilane MTMS, hexamethyldisilazane HMDZ, or trimethylethoxysilane TMES; the mass ratio of the hydrophobic modifier to the silicon source is 2 to 8:

20.

6. The preparation method of the aerogel dry water extinguishing agent as described in claim 1, characterized in that: In step S7, the mass ratio of the dry water mixture, surfactant, and hydrophobic SiO2 aerogel is 100:1~5:10~30.

7. An aerogel dry water extinguishing agent, characterized in that: The aerogel dry water extinguishing agent, prepared by the preparation method described in any one of claims 1-6, is a gel dry water droplet encapsulated by hydrophobic aerogel powder and is in the form of fine particles.

8. The application of the aerogel dry water extinguishing agent as described in claim 7 in the preparation of fire extinguishing patches, characterized in that: The porous material is immersed in the extinguishing agent, allowing the extinguishing agent particles to penetrate into the pores of the porous material to obtain the extinguishing material. The extinguishing material is then coated onto a temperature-controlled pyrolysis membrane, and after encapsulation and cutting, the extinguishing patch is obtained.

9. The application of the aerogel dry water extinguishing agent as described in claim 8 in the preparation of fire extinguishing patches, characterized in that: The porous material is an inorganic material, an inorganic material modified with organic material surface, or an organic-inorganic hybrid material, and the particle size of the porous material is 100-400 μm.

10. The application of the aerogel dry water extinguishing agent as described in claim 8 in the preparation of fire extinguishing patches, characterized in that: The temperature-controlled pyrolysis membrane is a phenolic resin film, an epoxy resin film, a polystyrene film, or a polybutyl acrylate film.

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