Preparation method of stable gel composite solid water fire extinguishing agent

Abstract

The invention discloses a preparation method of a stable gel composite solid water fire extinguishing agent. In order to overcome the key defect that water is separated out due to the fact that a shell is damaged in the long-term storage process of an existing solid water fire extinguishing agent, an organic-inorganic composite gelation technology is innovatively adopted. Through a specific preparation process, an aqueous solution and a modified hydrophobic solid material (such as nano silicon dioxide, stearate and the like) are mixed under specific conditions, and specific organogelators (such as high-molecular polymers, low-molecular-weight organogels and the like) are introduced to form a composite structure with a water phase cured by a stable gel network. Microscopically, the fire extinguishing agent is of a microcapsule structure in which gel-state water is wrapped by a hydrophobic material shell; macroscopically, the fire extinguishing agent keeps a dry powder flowing state.

Description

Technical Field

[0001] The invention belongs to the technical field of fire protection, and in particular relates to a method for preparing a stable gel composite solid water fire extinguishing agent. Background Art

[0002] Lithium-ion batteries are widely used due to their high energy density (such as new energy vehicles and energy storage systems), but fires caused by thermal runaway are characterized by high temperatures, strong re-ignition, and easy release of toxic gases. Although traditional water-based fire extinguishing agents can reduce the temperature when extinguishing lithium-ion battery fires, they may cause the battery short circuit to worsen; although dry powder fire extinguishing agents can isolate oxygen, their coverage is limited and it is difficult to penetrate the interior of the battery to suppress re-ignition; therefore, there is an urgent need to develop a new type of fire extinguishing agent that combines efficient cooling, long-term oxygen isolation, and resistance to re-ignition. Solid water fire extinguishing agents have a powdery appearance and combine the fire extinguishing efficiency of water with the fluidity of dry powder, showing unique advantages in fire fighting. However, when existing solid water fire extinguishing agents are stored for a long time, the water core wrapped by the surfactant is prone to water loss due to factors such as osmotic pressure and temperature fluctuations, resulting in a significant decrease in fire extinguishing efficiency with prolonged storage time; this problem seriously limits the practical application of solid water fire extinguishing agents, especially in industries such as industry and transportation that require long-term storage. How to solve the problem of water loss during long-term storage of solid water fire extinguishing agents has become the key to solid water fire extinguishing agents becoming special fire extinguishing agents for lithium-ion batteries. Summary of the Invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a method for preparing a stable gel composite solid water fire extinguishing agent.

[0004] In order to achieve the above-mentioned object, the method for preparing a stable gel composite solid water fire extinguishing agent provided by the present invention comprises the following steps performed in sequence:

[0005] 1) Weigh the following raw material components according to the following mass percentages and set aside: ultrafine hydrophobic powder carrier: 1.0-12.0%, inorganic flame retardant gel: 5.0-20.0%, organic gel factor: 0.5%-4.0%, water: balance to 100%;

[0006] 2) mixing the organogelator and water and stirring thoroughly to obtain a gel precursor solution;

[0007] 3) mixing the gel precursor solution and the inorganic flame retardant gel and stirring them thoroughly until the inorganic flame retardant gel is dispersed and mixed uniformly to obtain an organic-inorganic hybrid gel solution;

[0008] 4) injecting the organic-inorganic hybrid gel solution into the ultrafine hydrophobic powder carrier, and then placing the mixture in a blender for stirring to obtain a gel composite solid water fire extinguishing agent having a core-shell structure with a hydrophobic outer shell and a gel water inner core.

[0009] The ultrafine hydrophobic powder carrier is selected from at least one of hydrophobized silica powder, carbon fluoride powder, hydrophobized ceramic powder, hydrophobized metal oxide powder, hydrophobized insoluble salt powder, hydrophobized polymer powder, hydrophobized biomass carbon powder and hydrophobized mineral powder.

[0010] The inorganic flame retardant gel is selected from at least one of ammonium dihydrogen phosphate, decabromodiphenyl ether, tetrabromobisphenol A, aluminum hydroxide, magnesium hydroxide, antimony trioxide, triphenyl phosphate, melamine, polysiloxane, ammonium polyphosphate-pentaerythritol-melamine expansion system, sodium bicarbonate, potassium carbonate and zinc borate.

[0011] The organic gel factor is selected from at least one of polyacrylamide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, sodium polyacrylate, polyvinyl pyrrolidone, polyacrylamide-sodium acrylate copolymer, sodium alginate, gelatin, agar, chitosan, poly (N-isopropylacrylamide) and carrageenan.

[0012] The specific surface area of ​​the ultrafine hydrophobic powder carrier is 200 to 500 m 2 / g.

[0013] In step 2), the stirring speed is 700-1200 r / min and the stirring time is 1-5 min.

[0014] In step 3), the stirring speed is 400-800 r / min and the stirring time is 0.5-5 min.

[0015] In step 4), the stirring speed is 600-1300 r / min and the stirring time is 10-15 min.

[0016] The particle size of the ultrafine hydrophobic powder carrier is 120 to 400 μm.

[0017] The main principles of the preparation method for the stable gel composite solid water fire extinguishing agent provided by the present invention are: using a hydrophilic organic polymer as the gel component, which locks in moisture through hydrogen bonding and physical encapsulation, thereby inhibiting water loss from the solid water particles. The gel not only enhances storage stability but also forms a viscous coating during fire extinguishing, prolonging the cooling time and isolating oxygen, further reducing the risk of re-ignition of battery fires. The use of an inorganic flame-retardant gel effectively interrupts the chain reaction and enhances the fire extinguishing efficiency of the solid water fire extinguishing agent. Microscopically, the gel solution is coated with an ultrafine hydrophobic powder carrier, which separates the gel components into a discontinuous state, thereby reducing the conductivity of the gel solution and preventing electrical conduction in battery fires. This fire extinguishing agent can maintain its performance during long-term storage, achieving efficient fire extinguishing and safe application.

[0018] Compared with the existing technology, the present invention has the following beneficial effects:

[0019] (1) The organic polymer organogel factor added in the present invention has made a breakthrough in solving the problem of water loss during long-term storage of solid water. Organic polymer organogel factors (such as polyacrylamide and sodium alginate) are now used to form a hydrogen bond network to physically lock in moisture, achieving a water loss rate of less than 5% within 2 years and improving storage stability by 10 times.

[0020] (2) This invention innovatively incorporates a triple fire extinguishing mechanism: the inorganic flame retardant gel vaporizes to absorb heat (physical cooling, heat absorption ≥ 2260 kJ / kg); the organic melt gel forms a viscous coating to isolate oxygen; and the inorganic flame retardant gel's heated products interrupt free radical chains (chemical flame suppression). The hydrophobic powder separates the gel into micron-sized isolated units, completely eliminating the risk of electrical conductivity and significantly improving the fire extinguishing efficiency of the solid water fire extinguishing agent.

[0021] (3) The present invention has a simple step-by-step process, in which mechanical stirring is performed during the preparation process, and no steps such as stamping or heating are required, so the production cost is low and it is beneficial to popularization and application.

[0022] (4) The solid water fire extinguishing agent of the present invention has a powdery appearance at room temperature and pressure, which makes it easy to store and can the fire extinguishing agent, saving transportation and maintenance costs. It can be used with existing fire extinguisher equipment and has wide applicability. DETAILED DESCRIPTION

[0023] This section provides a detailed and precise description of the embodiments of the present invention. Obviously, the examples described here represent only a portion of the numerous embodiments of the present invention, and are not exhaustive. Based on the embodiments of the present invention, all other embodiments that can be devised by those skilled in the art without inventive work are encompassed within the scope of protection of the present invention.

[0024] Example 1

[0025] The raw materials and mass ratios used in this embodiment are: the ultrafine hydrophobic powder carrier is 5.6% hydrophobized silica powder; the organic gel factor is 0.5% sodium polyacrylate, the inorganic flame retardant gel is 12.2% ammonium dihydrogen phosphate, and water, the balance is 100%;

[0026] 1) Sodium polyacrylate and water were mixed and stirred thoroughly with mechanical stirring at a speed of 800 r / min for 3 min to form a uniform gel precursor solution;

[0027] 2) mixing the gel precursor solution obtained in step 1) with ammonium dihydrogen phosphate and stirring thoroughly, using mechanical stirring at a stirring speed of 400 r / min for 30 seconds to obtain an organic-inorganic hybrid gel solution;

[0028] 3) injecting the organic-inorganic hybrid gel solution into the hydrophobized silica powder, and then placing it in a blender and stirring at a stirring speed of 800 r / min for 7 min to obtain a granular gel composite solid water fire extinguishing agent having a core-shell structure with a hydrophobic shell and a gel-like water core.

[0029] After experimental measurement, the liquid water content of the gel composite solid water fire extinguishing agent that is not wrapped by the solid hydrophobic material is 0.6%, and the D90 particle size of the particles is 28mm. In the fire extinguishing test carried out on a 230Ah lithium-ion battery heated to a fire state, the experimental results clearly showed that the fire extinguishing agent can quickly extinguish the open flame within 4s and ensure that the battery does not reignite. Furthermore, through the standard test process of the cup burner, the fire extinguishing concentration of the gel composite solid water fire extinguishing agent provided by the present invention for a standard methane flame is accurately quantified as 31g / m 3 .

[0030] In addition, the above-mentioned gel composite solid water fire extinguishing agent can also extinguish battery fires including lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, sodium batteries, potassium batteries, zinc batteries, vanadium liquid flow batteries, solid-state batteries, lithium-sulfur batteries, sodium ion batteries, potassium ion batteries, zinc ion batteries, and magnesium batteries.

[0031] Example 2

[0032] The raw materials and mass ratios used in this embodiment are as follows: the ultrafine hydrophobic powder carrier is 6.1% carbon fluoride powder; the organic gel factor is 1.4% polyacrylamide; the inorganic flame retardant gel is 13.2% sodium bicarbonate; and water, the balance is 100%;

[0033] The specific preparation process is as follows:

[0034] 1) Mixing polyacrylamide and water and stirring them thoroughly with mechanical stirring at a stirring speed of 800 r / min for 2 min to form a uniform gel precursor solution;

[0035] 2) mixing the gel precursor solution obtained in step 1) with sodium bicarbonate and stirring thoroughly, using mechanical stirring at a stirring speed of 400 r / min for 30 seconds to obtain an organic-inorganic hybrid gel solution;

[0036] 3) injecting the organic-inorganic hybrid gel into the carbon fluoride powder, and then placing it in a blender and stirring it at a stirring speed of 800 r / min for 9 minutes to obtain a gel composite solid water fire extinguishing agent with a core-shell structure having a hydrophobic shell and a gel water core.

[0037] After experimental measurement, the liquid water content of the gel composite solid water fire extinguishing agent that is not wrapped by the solid hydrophobic material is 1.2%, and the D90 particle size of the particles is 30mm. In the fire extinguishing test carried out on a 230Ah lithium-ion battery heated to a fire state, the experimental results clearly showed that the fire extinguishing agent can quickly extinguish the open flame within 5s and ensure that the battery does not reignite. Furthermore, through the standard test process of the cup burner, the fire extinguishing concentration of the gel composite solid water fire extinguishing agent provided by the present invention for a standard methane flame is accurately quantified as 31g / m3.

[0038] Example 3

[0039] The raw materials and mass ratios used in this embodiment are as follows: the ultrafine hydrophobic powder carrier is 5.1% hydrophobized ceramic powder; the organic gel factor is 1.6% sodium alginate; the inorganic flame retardant gel is 13.2% aluminum hydroxide powder; and water, the balance to 100%.

[0040] The specific preparation process is as follows:

[0041] 1) Sodium alginate and water were mixed and stirred thoroughly with mechanical stirring at a speed of 800 r / min for 3 min to form a uniform gel precursor solution;

[0042] 2) mixing the gel precursor solution obtained in step 1) with aluminum hydroxide powder and stirring them thoroughly, using mechanical stirring at a stirring speed of 400 r / min for 40 seconds to obtain an organic-inorganic hybrid gel solution;

[0043] 3) injecting the organic-inorganic hybrid gel into the hydrophobized ceramic powder, and then placing it in a blender and stirring at a stirring speed of 1000 r / min for 5 min to obtain a gel composite solid water fire extinguishing agent with a core-shell structure having a hydrophobic shell and a gel-like water core.

[0044] After experimental determination, the liquid water content of the gel composite solid water fire extinguishing agent that is not wrapped by the solid hydrophobic material is 1.0%, and the D90 particle size of the particles is 28mm. In the fire extinguishing test carried out on a 230Ah lithium-ion battery heated to a fire state, the experimental results clearly showed that the fire extinguishing agent can quickly extinguish the open flame within 5s and ensure that the battery does not reignite. Furthermore, through the standard test process of the cup burner, the fire extinguishing concentration of the gel composite solid water fire extinguishing agent provided by the present invention for a standard methane flame is accurately quantified as 33g / m 3 .

[0045] Comparative Example 1

[0046] This comparative example is a traditional solid water fire extinguishing agent preparation method, compared with Examples 1, 2, and 3: hydrophobic fumed silica 7.8%, water, the balance to 100%. The preparation method is as follows:

[0047] 1) Stir in a blender at a medium speed of 1000 r / min for 10 minutes to allow the water to be coated with the carrier powder to form particles;

[0048] 2) Sieving or centrifuging to obtain solid water particles with uniform particle size;

[0049] 3) The obtained solid water particles are placed in an electric vibrating screen machine and passed through a sieve to obtain ordinary solid water materials with a particle size of 50 to 100 μm.

[0050] The performance parameters of the water-solidifying materials of Examples 1, 2, 3 and Comparative Example 1 were compared respectively, and the test method was as follows:

[0051] Compressive strength test: Take 30g of solid water materials of different particle sizes and place them in an acrylic pressure tank. By compressing nitrogen into the tank, slowly increase the pressure in the pressure tank at a rate of 0.05MPa / s. Stop increasing the pressure when obvious liquid precipitation is observed. If precipitation continues, stop increasing the pressure until 10% liquid is precipitated and record the value; if it is insufficient, continue to slowly increase the pressure until 10% liquid is precipitated. Do each example three times and take the average value. The measured pressure is the compressive strength.

[0052] Water retention performance test: 30g of water-solidifying materials of different particle sizes were taken and placed in a limited space. After shaking, the four groups of examples were left to stand for one month, and the proportion of precipitation was calculated based on the volume as the particle breakage rate.

[0053] Table 1

[0054] sample Example 1 Example 2 Example 3 Comparative Example 1 Compressive strength (MPa) 1.31 1.01 1.21 0.45 Water retention rate (%) 2.8 3.2 4.9 43

[0055] Performance tests have shown that adding inorganic flame retardant gel to the powder and organic gel factor to the liquid can achieve triple fire extinguishing and quickly extinguish the fire; at the same time, the addition of organic gel factor allows the water-solidifying material to be preserved for a long time while retaining its original fire extinguishing properties.

Claims

1. A method for preparing a stable gel composite solid water fire extinguishing agent, characterized in that: The preparation method comprises the following steps performed in sequence: 1) Weigh the following raw material components according to the following mass percentages and set aside: ultrafine hydrophobic powder carrier: 1.0-12.0%, inorganic flame retardant gel: 5.0-20.0%, organic gel factor: 0.5%-4.0%, water: balance to 100%; 2) mixing the organogelator and water and stirring thoroughly to obtain a gel precursor solution; 3) mixing the gel precursor solution and the inorganic flame retardant gel and stirring them thoroughly until the inorganic flame retardant gel is dispersed and mixed uniformly to obtain an organic-inorganic hybrid gel solution; 4) injecting the organic-inorganic hybrid gel solution into the ultrafine hydrophobic powder carrier, and then placing the mixture in a blender for stirring to obtain a gel composite solid water fire extinguishing agent having a core-shell structure with a hydrophobic outer shell and a gel water inner core.

2. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: The ultrafine hydrophobic powder carrier is selected from at least one of hydrophobized silica powder, carbon fluoride powder, hydrophobized ceramic powder, hydrophobized metal oxide powder, hydrophobized insoluble salt powder, hydrophobized polymer powder, hydrophobized biomass carbon powder and hydrophobized mineral powder.

3. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: The inorganic flame retardant gel is selected from at least one of ammonium dihydrogen phosphate, decabromodiphenyl ether, tetrabromobisphenol A, aluminum hydroxide, magnesium hydroxide, antimony trioxide, triphenyl phosphate, melamine, polysiloxane, ammonium polyphosphate-pentaerythritol-melamine expansion system, sodium bicarbonate, potassium carbonate and zinc borate.

4. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: The organic gel factor is selected from at least one of polyacrylamide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, sodium polyacrylate, polyvinyl pyrrolidone, polyacrylamide-sodium acrylate copolymer, sodium alginate, gelatin, agar, chitosan, poly (N-isopropylacrylamide) and carrageenan.

5. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: The specific surface area of ​​the ultrafine hydrophobic powder carrier is 200 to 500 m 2 / g.

6. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: In step 2), the stirring speed is 700-1200 r / min and the stirring time is 1-5 min.

7. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: In step 3), the stirring speed is 400-800 r / min and the stirring time is 0.5-5 min.

8. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: In step 4), the stirring speed is 600-1300 r / min and the stirring time is 10-15 min.

9. The method for preparing a stable gel composite solid water fire extinguishing agent according to claim 1, characterized in that: The particle size of the ultrafine hydrophobic powder carrier is 120 to 400 μm.