Low temperature and low corrosive thermal aerosol fire extinguishing medium, method of making and use thereof

Abstract

The application relates to the field of gas fire extinguishing of fire-fighting equipment, and discloses a low-temperature and low-corrosion hot aerosol fire extinguishing medium, a preparation method and application thereof. The hot aerosol fire extinguishing medium comprises an oxidant and modified aluminum hydroxide, the oxidant is a mixture of strontium nitrate, potassium organic acid and chlorate, the content of silane groups in the modified aluminum hydroxide is 10-30 wt%, and the weight ratio of the oxidant to the modified aluminum hydroxide is 1:0.01-0.5. The hot aerosol fire extinguishing medium is stable in performance during combustion, can effectively reduce the combustion temperature, significantly improve the fire extinguishing efficiency, and simultaneously reduce the corrosiveness to electrical equipment.

Description

Technical Field

[0001] This invention relates to the field of gas extinguishing in fire protection equipment, specifically to a low-temperature and low-corrosive thermal aerosol extinguishing medium, its preparation method, and its application. Background Technology

[0002] Thermal aerosol fire extinguishing agents have gradually gained widespread attention as a new type of fire extinguishing technology. They have replaced traditional halon fire extinguishing agents due to their advantages such as shorter atmospheric persistence, environmental friendliness, and high fire extinguishing performance, becoming a new type of product in fire extinguishing equipment. The fire extinguishing principle of thermal aerosol fire extinguishing agents mainly involves the aerosol generator undergoing a combustion reaction after ignition, producing fire extinguishing substances to extinguish the flames.

[0003] Thermal aerosol fire extinguishing agents are classified into two types based on their primary oxidant components: Type K thermal aerosol fire extinguishing agents, which use potassium nitrate as the oxidant, and Type S thermal aerosol fire extinguishing agents, which use strontium nitrate as the oxidant in their aerosol components. However, in practice, it has been found that Type K thermal aerosol fire extinguishing agents can cause short circuits or corrosion to electrical equipment, while Type S thermal aerosol fire extinguishing agents, while releasing extinguishing substances through combustion, also eject high-temperature flames and residues from the nozzle, posing a risk of secondary ignition. Patent CN115364420B discloses a thermal aerosol fire extinguishing agent composed of potassium nitrate, strontium nitrate, dicyandiamide, epoxy resin, phenolic resin, and potassium oxalate. This thermal aerosol fire extinguishing agent avoids the use of magnesium powder, increases the safety performance of the thermal aerosol medium during production and storage, and lowers the extinguishing agent temperature; however, this fire extinguishing agent still exhibits strong corrosivity to electrical equipment.

[0004] Therefore, there is an urgent need for a thermal aerosol fire extinguishing medium that can maintain stable performance during combustion, reduce combustion temperature, effectively improve fire extinguishing efficiency, and reduce corrosion to electrical equipment. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of high combustion temperature, strong corrosivity, and poor extinguishing performance of existing thermal aerosol fire extinguishing agents, and to provide a low-temperature and low-corrosive thermal aerosol fire extinguishing medium, its preparation method, and its application. This thermal aerosol fire extinguishing medium has stable performance during combustion, can effectively reduce combustion temperature, significantly improve fire extinguishing efficiency, and at the same time reduce corrosion to electrical equipment.

[0006] To achieve the above objectives, the first aspect of the present invention provides a low-temperature and low-corrosion thermal aerosol fire extinguishing medium, the thermal aerosol fire extinguishing medium comprising an oxidant and modified aluminum hydroxide;

[0007] The oxidant is a mixture of strontium nitrate, potassium organic acid, and chlorate;

[0008] The modified aluminum hydroxide contains 10-30 wt% silane groups.

[0009] The weight ratio of the oxidant to the modified aluminum hydroxide is 1:0.01-0.5.

[0010] The second aspect of the present invention provides a method for preparing a low-temperature and low-corrosive thermal aerosol fire extinguishing medium, comprising mixing an oxidant, modified aluminum hydroxide, a combustible agent and a binder, adding a second solvent and then drying.

[0011] A third aspect of the present invention provides an application of the above-described thermal aerosol extinguishing medium in extinguishing fires in electrical equipment.

[0012] Through the above technical solutions, the low-temperature and low-corrosion thermal aerosol fire extinguishing medium, its preparation method, and its application provided by this invention achieve the following beneficial effects:

[0013] In this invention, a mixture of strontium nitrate, potassium organic acid, and chlorate is selected as an oxidant, which works synergistically with silane-modified aluminum hydroxide to stabilize the performance of the thermal aerosol fire extinguishing medium during combustion, effectively reduce the combustion temperature (less than 200°C), significantly improve the fire extinguishing performance (fire extinguishing efficiency less than 0.4) and combustion utilization rate (residual rate less than 6.5 wt%), while reducing the corrosiveness of the thermal aerosol medium. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] In a first aspect, the present invention provides a low-temperature and low-corrosion thermal aerosol fire extinguishing medium, wherein the thermal aerosol fire extinguishing medium comprises an oxidant and modified aluminum hydroxide;

[0016] The oxidant is a mixture of strontium nitrate, potassium organic acid, and chlorate;

[0017] The modified aluminum hydroxide contains 10-30 wt% silane groups.

[0018] The weight ratio of the oxidant to the modified aluminum hydroxide is 1:0.01-0.5.

[0019] In this invention, the thermal aerosol extinguishing medium can reduce combustion temperature, improve extinguishing performance, and reduce corrosivity. Based on the principle, the inventors hypothesize that: Potassium organic acid and modified aluminum hydroxide preferentially decompose in the early stages of combustion. This process is usually accompanied by an endothermic reaction and releases a large amount of non-combustible gas. The rapid expansion of these gases carries away a significant amount of heat, effectively reducing the combustion temperature. Secondly, the silane-modified aluminum hydroxide introduces silane groups on its surface, improving its dispersibility and compatibility in the thermal aerosol. During combustion, the modified aluminum hydroxide dehydrates to generate modified aluminum oxide. This product can be uniformly mixed with active products such as strontium oxide generated from the combustion of strontium nitrate, forming extremely fine composite particles. These composite particles can efficiently absorb and neutralize combustion free radicals in the flame, thereby improving extinguishing performance through chemical action. At high combustion temperatures, the silane groups of the modified aluminum hydroxide may react with alkali metal oxides generated after the combustion of the oxidant, generating weakly alkaline potassium silicate or strontium silicate, thus reducing the corrosivity of the thermal aerosol.

[0020] Combustion temperature refers to the highest temperature at the nozzle of the fire extinguishing device during the process of releasing hot aerosol extinguishing medium.

[0021] Combustion time refers to the time from ignition of a thermal aerosol extinguishing agent to complete combustion and cessation of the reaction, when no smoke or residue is emitted from the extinguishing device. Combustion time reflects the burning rate of the aerosol extinguishing agent; a higher burning rate results in a shorter combustion time, indicating more intense combustion.

[0022] Extinguishing time refers to the time from when the thermal aerosol extinguishing medium is sprayed from the nozzle to when the flaming fire is extinguished.

[0023] Fire extinguishing efficiency refers to the ratio of extinguishing time to combustion time. The fire extinguishing test of this invention is conducted in a relatively small space, where the aerosol generated by the combustion of the extinguishing agent can rapidly diffuse around the fire source in a very short time. When the aerosol extinguishing agent successfully extinguishes the fire before it completes combustion, using the ratio of extinguishing time to combustion time as a standard for evaluating its fire extinguishing efficiency is more accurate. When the fire extinguishing efficiency ratio is less than 1, the fire extinguishing efficiency reflects the amount of extinguishing medium consumed during extinguishing; the lower the percentage of the ratio of extinguishing time to combustion time, the higher the fire extinguishing efficiency.

[0024] The residue rate refers to the percentage calculated by comparing the solid residue remaining after the thermal aerosol extinguishing medium has completely burned with the original mass of the aerosol extinguishing medium. A lower residue rate indicates more complete combustion and higher utilization of the thermal aerosol extinguishing medium.

[0025] According to the present invention, preferably, the content of silane groups in the modified aluminum hydroxide is 15-25 wt%.

[0026] More preferably, the weight ratio of the oxidant to the modified aluminum hydroxide is 1:0.02-0.2.

[0027] In this invention, the content of silane groups in modified aluminum hydroxide is measured by X-ray photoelectron spectroscopy analysis.

[0028] According to the present invention, preferably, the weight ratio of strontium nitrate, potassium organic acid and chlorate in the oxidant is 10-20:1-4:1.

[0029] The organic potassium acid is at least one of potassium oxalate, potassium citrate, potassium gluconate, potassium tartrate, and potassium acetate.

[0030] The chlorate is at least one of potassium chlorate, magnesium chlorate, sodium chlorate, strontium chlorate, and ammonium chlorate.

[0031] In this invention, when the weight ratio of strontium nitrate, potassium organic acid, and chlorate in the oxidant meets the above-mentioned range, the fire extinguishing performance can be further improved and the corrosiveness to electrical equipment can be reduced.

[0032] According to the present invention, preferably, the weight ratio of strontium nitrate, potassium organic acid and chlorate in the oxidant is 14-17:2-3:1.

[0033] According to the present invention, preferably, the organic acid potassium is a mixture of potassium oxalate and potassium citrate;

[0034] The weight ratio of potassium oxalate to potassium citrate is 5-20:1.

[0035] In this invention, when the organic acid potassium meets the above-mentioned range, the corrosiveness of thermal aerosol to electrical equipment can be further reduced.

[0036] According to the present invention, preferably, the weight ratio of potassium oxalate to potassium citrate is 8-15:1.

[0037] According to the present invention, preferably, the method for preparing the modified aluminum hydroxide includes: mixing aluminum hydroxide and a coupling agent in the presence of a first solvent, and heating and stirring; wherein the weight ratio of aluminum hydroxide to coupling agent is 1:0.1-2.

[0038] According to the present invention, preferably, the weight ratio of aluminum hydroxide to coupling agent is 1:0.5-1.

[0039] According to the present invention, preferably, the coupling agent is selected from at least one of vinyltriethoxysilane, γ-aminopropyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane;

[0040] The first solvent is selected from at least one of water, ethanol, methanol, and acetonitrile.

[0041] According to the present invention, preferably, the temperature of the heating and stirring is 60-120°C, more preferably 80-100°C.

[0042] According to the present invention, preferably, the heating and stirring time is 40-100 min, more preferably 60-80 min.

[0043] In this invention, preferably, the first solvent is a mixture of water and ethanol, and more preferably, the volume ratio of water to ethanol is 2-6:1.

[0044] According to the present invention, preferably, the method for preparing the modified aluminum hydroxide further includes drying. The present invention does not limit the drying method; preferably, the drying is at least one of vacuum drying, spray drying, and airflow drying. More preferably, the drying temperature is 80-120°C, and the drying time is 2-8 hours.

[0045] According to the present invention, preferably, the thermal aerosol extinguishing medium further includes a combustible agent and a binder;

[0046] The weight ratio of the oxidant to the combustible agent is 1:0.1-5;

[0047] The weight ratio of the oxidant to the binder is 1:0.01-1.

[0048] More preferably, the weight ratio of the oxidant to the combustible agent is 1:0.2-0.8.

[0049] More preferably, the weight ratio of the oxidant to the binder is 1:0.03-0.06.

[0050] According to the present invention, preferably, the combustible agent is selected from at least one of lactose, sucrose, melamine, magnesium hydride and lithium hydride;

[0051] The adhesive is selected from at least one of phenolic resin, epoxy resin, shellac, polyvinyl alcohol, and idutol.

[0052] According to the present invention, preferably, the combustible agent is a mixture of lactose and magnesium hydride;

[0053] The weight ratio of lactose to magnesium hydride is 1-5:1.

[0054] More preferably, the weight ratio of lactose to magnesium hydride is 2.5-3.5:1.

[0055] Secondly, the present invention provides a method for preparing a low-temperature and low-corrosive thermal aerosol fire extinguishing medium, which involves mixing an oxidant, modified aluminum hydroxide, a combustible agent and a binder, adding a second solvent and then drying.

[0056] In this invention, the preparation method further includes pre-treating the oxidant, modified aluminum hydroxide, flammable agent and binder before mixing, wherein the pre-treatment includes pre-drying and pulverizing.

[0057] According to the present invention, preferably, the pre-drying temperature is 40-80°C, and the pre-drying time is 6-24 hours. The oxidant, modified aluminum hydroxide, flammable agent, and binder are pre-dried to reduce their moisture content to less than 2 wt%.

[0058] In this invention, there are no special restrictions on the pulverization method, as long as the oxidant, modified aluminum hydroxide, combustible agent and binder can be pulverized. Preferably, the pulverization method is at least one of ultrafine pulverization, high-shear wet pulverization and ball milling.

[0059] More preferably, the particle size of the oxidant, modified aluminum hydroxide, combustible agent, and binder powder is less than 10 μm.

[0060] According to the present invention, preferably, the mixing method is at least one of stirring mixing, ball milling mixing, and shear mixing.

[0061] More preferably, the mixing is ball milling, which includes adding a second solvent to wet the mixture during ball milling, followed by further ball milling, with a total ball milling time of 80-200 min.

[0062] According to the present invention, preferably, the second solvent includes at least one of acetone, ethanol and acetonitrile.

[0063] More preferably, the weight ratio of the second solvent to the oxidant is 0.5-2:1.

[0064] According to the present invention, preferably, the particle size of the thermal aerosol extinguishing medium is less than 4 μm.

[0065] Thirdly, the present invention provides an application of the above-mentioned thermal aerosol fire extinguishing medium in fire extinguishing of electrical equipment.

[0066] The present invention will be described in detail below with reference to the embodiments.

[0067] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0068] Preparation Example 1

[0069] Aluminum hydroxide and γ-aminopropyltriethoxysilane were dispersed in a mixed solution of water and ethanol (volume ratio 4:1), stirred at 80°C for 60 min, and then vacuum filtered to obtain a powder. The powder was placed in a drying oven and dried at 100°C for 4 h to obtain modified aluminum hydroxide-a. The weight ratio of aluminum hydroxide to γ-aminopropyltriethoxysilane was 1:0.5; the content of silane groups in the modified aluminum hydroxide was 22 wt%.

[0070] Preparation Example 2

[0071] Aluminum hydroxide and γ-aminopropyltriethoxysilane were dispersed in a mixed solution of water and ethanol (volume ratio 4:1), stirred at 80°C for 60 min, and then vacuum filtered to obtain a powder. The powder was placed in a drying oven and dried at 100°C for 4 h to obtain modified aluminum hydroxide-b. The weight ratio of aluminum hydroxide to γ-aminopropyltriethoxysilane was 1:0.1, and the content of silane groups in the modified aluminum hydroxide was 5 wt%.

[0072] Preparation Example 3

[0073] Aluminum hydroxide and γ-aminopropyltriethoxysilane were dispersed in a mixed solution of water and ethanol (volume ratio 4:1), stirred at 100°C for 60 min, and then vacuum filtered to obtain a powder. The powder was placed in a drying oven and dried at 100°C for 4 h to obtain modified aluminum hydroxide-c. The weight ratio of aluminum hydroxide to γ-aminopropyltriethoxysilane was 1:1.5; the content of silane groups in the modified aluminum hydroxide was 33 wt%.

[0074] Preparation Example 4

[0075] Aluminum hydroxide and vinyltriethoxysilane were dispersed in a mixed solution of ethanol and stirred at 80°C for 70 min. After vacuum filtration, a powder was obtained. The powder was placed in a drying oven and dried at 100°C for 4 h to obtain modified aluminum hydroxide-d. The weight ratio of aluminum hydroxide to γ-aminopropyltriethoxysilane was 1:1.5; the content of silane groups in the modified aluminum hydroxide was 26 wt%.

[0076] Example 1

[0077] 8.5 kg of strontium nitrate, 0.9 kg of potassium oxalate, 0.1 kg of potassium citrate, 0.5 kg of potassium chlorate, 1.5 kg of lactose, 0.5 kg of magnesium hydride, 0.5 kg of p-tert-butylphenol formaldehyde resin (weight average molecular weight of 1200 g / mol) and 0.3 kg of modified aluminum hydroxide-a were ball-milled for 50 min. After adding 10 L of acetone, the mixture was ball-milled for another 60 min. After air separation, the mixture was placed in a vacuum oven and dried at 50 °C for 6 h to prepare fire extinguishing medium-1 with an average particle size of 2 μm.

[0078] Example 2

[0079] The extinguishing medium was prepared according to the method of Example 1, except that an equal mass of modified aluminum hydroxide-d was used instead of modified aluminum hydroxide-a to prepare extinguishing medium-2 with an average particle size of 2 μm.

[0080] Example 3

[0081] The fire extinguishing medium was prepared in accordance with the method of Example 1, except that the weight of modified aluminum hydroxide-a was 2 kg, and fire extinguishing medium-3 with an average particle size of 2 μm was prepared.

[0082] Example 4

[0083] 7.3 kg of strontium nitrate, 1.5 kg of potassium oxalate, 0.2 kg of potassium citrate, 1 kg of potassium chlorate, 1.5 kg of lactose, 0.5 kg of magnesium hydride, 0.5 kg of p-tert-butylphenol formaldehyde resin (weight average molecular weight of 1200 g / mol) and 0.3 kg of modified aluminum hydroxide-a were ball-milled for 50 min. After adding 10 L of acetone, the mixture was ball-milled for another 60 min. After air separation, the mixture was placed in a vacuum oven and dried at 50 °C for 6 h to prepare fire extinguishing medium-4 with an average particle size of 2 μm.

[0084] Example 5

[0085] 8.5 kg of strontium nitrate, 1 kg of potassium oxalate, 1 kg of potassium chlorate, 1.5 kg of lactose, 0.5 kg of magnesium hydride, 0.5 kg of p-tert-butylphenol formaldehyde resin (weight average molecular weight of 1200 g / mol) and 0.3 kg of modified aluminum hydroxide-a were ball-milled for 50 min. After adding 15 L of acetone, the mixture was ball-milled for another 60 min. After air separation, the mixture was placed in a vacuum oven and dried at 50 °C for 6 h to prepare fire extinguishing medium-5 with an average particle size of 2 μm.

[0086] Example 6

[0087] 8.5 kg of strontium nitrate, 0.9 kg of potassium oxalate, 0.1 kg of potassium citrate, 0.5 kg of potassium chlorate, 7.5 kg of lactose, 2.5 kg of magnesium hydride, 0.5 kg of p-tert-butylphenol formaldehyde resin (weight average molecular weight of 1200 g / mol) and 0.3 kg of modified aluminum hydroxide-a were ball-milled for 50 min. After adding 10 L of acetone, the mixture was ball-milled for another 60 min. After air separation, the mixture was placed in a vacuum oven and dried at 50 °C for 6 h to prepare fire extinguishing medium-6 with an average particle size of 2 μm.

[0088] Example 7

[0089] 8.5 kg of strontium nitrate, 0.9 kg of potassium oxalate, 0.1 kg of potassium citrate, 0.5 kg of potassium chlorate, 2.5 kg of lactose, 0.5 kg of p-tert-butylphenol formaldehyde resin (weight average molecular weight of 1200 g / mol), and 0.3 kg of modified aluminum hydroxide-a were ball-milled for 50 min. After adding 10 L of acetone, the mixture was ball-milled for another 60 min. After air separation, the mixture was placed in a vacuum oven and dried at 50 °C for 6 h to prepare fire extinguishing medium-7 with an average particle size of 2 μm.

[0090] Comparative Example 1

[0091] The fire extinguishing medium was prepared according to the method of Example 1, except that an equal mass of modified aluminum hydroxide-b was used instead of modified aluminum hydroxide-a to prepare fire extinguishing medium-a with an average particle size of 2μm.

[0092] Comparative Example 2

[0093] The fire extinguishing medium was prepared according to the method of Example 1, except that an equal mass of modified aluminum hydroxide-c was used instead of modified aluminum hydroxide-a to prepare fire extinguishing medium-b with an average particle size of 2μm.

[0094] Comparative Example 3

[0095] The fire extinguishing medium was prepared according to the method of Example 1, except that the weight of modified aluminum hydroxide-a was 5.5 kg, and fire extinguishing medium-c with an average particle size of 6 μm was prepared.

[0096] Comparative Example 4

[0097] 8.5 kg of strontium nitrate, 1.5 kg of potassium nitrate, 1.5 kg of lactose, 0.5 kg of magnesium hydride, 0.5 kg of p-tert-butylphenol formaldehyde resin (weight average molecular weight of 1700 g / mol) and 0.3 kg of modified aluminum hydroxide-a were ball-milled for 50 min. After adding 10 L of acetone, the mixture was ball-milled for another 60 min. After air separation, the mixture was placed in a vacuum oven and dried at 50 °C for 6 h to prepare fire extinguishing medium-d with an average particle size of 2 μm.

[0098] Comparative Example 5

[0099] The extinguishing medium was prepared according to the method of Example 1, except that modified aluminum hydroxide was not added, and an extinguishing medium with an average particle size of 2 μm-e was obtained.

[0100] Test Example 1

[0101] The combustion temperature, combustion time, extinguishing time, and residual rate of the extinguishing media in the examples and comparative examples were tested, and the test results are shown in Table 1.

[0102] Test Method: A fire extinguishing device containing 2 kg of the extinguishing medium prepared in the examples and comparative examples was placed in a 3 m³ test space. The fuel pan was positioned in the center of the test space, with an area of ​​0.1 m² and a bottom height of 200 mm from the ground. A 30 mm thick layer of n-heptane was injected into the fuel pan, with the liquid level no more than 50 mm from the edge of the pan, and a water pad was placed at the bottom. The n-heptane in the pan was ignited, pre-burned for 30 seconds, and all openings in the test space were closed. The fire extinguishing device was manually activated. The time to extinguish the n-heptane fire and the time to stop the combustion of the extinguishing medium were monitored using a temperature sensor or infrared camera. The aerosol extinguishing agent spraying process was filmed using a high-speed infrared thermal imager at a frame rate of 100 fps and a filming temperature range of 150-600℃. Frame-by-frame playback and software analysis were used to calculate the highest temperature at the nozzle. After combustion, the remaining solid residue was weighed.

[0103] Test Example 2

[0104] Take four brass plates, polish them with 200-grit sandpaper, then rinse and wash them with tap water using a stiff brush, and finally wash and dry them with anhydrous ethanol. Place the treated brass plates in a 60℃ electric drying oven for 60 minutes. Use tweezers to place the four brass plates flat in four petri dishes. Then place two of the petri dishes diagonally across the experimental room, 100 mm from the ground and 200 mm from each adjacent wall. Place the other two petri dishes diagonally across the experimental room, 100 mm from the ceiling and 200 mm from each adjacent wall, alternating with the two petri dishes on the ground.

[0105] A fire extinguishing device was placed in the test room. The fire extinguishing media prepared in the examples and comparative examples were ignited, and a stopwatch was used to time the process. After 30 minutes, the petri dish containing the test plate was removed and placed in a constant temperature and humidity chamber at 30°C and 85% relative humidity for 24 hours. The color change was then observed. The above experiment was performed twice in parallel. The brass plate was observed for any obvious color change, and the result with the strongest corrosiveness was taken as the test result. The experimental results are shown in Table 1.

[0106] Table 1

[0107] Burning time (s) Combustion temperature (°C) Fire extinguishing time (s) Fire extinguishing efficiency Residual rate (wt%) Brass plate color Example 1 12.6 177 3.1 0.25 3.2 No significant changes Example 2 11.2 185 3.8 0.34 4.7 No significant changes Example 3 10.5 170 3.2 0.31 5.8 No significant changes Example 4 10.8 189 3.7 0.34 5.2 No significant changes Example 5 11.3 198 4.2 0.37 3.8 No significant changes Example 6 14.2 194 5.6 0.39 6.3 No significant changes Example 7 9.2 183 3.5 0.38 4.1 No significant changes Comparative Example 1 8.5 286 4.2 0.49 9.5 There are obvious rust marks Comparative Example 2 10.3 235 5.4 0.52 12.1 There are obvious rust marks Comparative Example 3 12.1 228 6.8 0.56 10.1 There are obvious rust marks Comparative Example 4 11.2 220 5.3 0.47 8.6 Very obvious rust Comparative Example 5 7.1 342 4.3 0.61 15.8 There are obvious rust marks

[0108] Table 1 shows that, based on the data from Example 1 and Comparative Example 1, the use of strontium nitrate, potassium organic acid, and chlorate as oxidants in this invention can significantly reduce the corrosiveness of the thermal aerosol extinguishing medium to electrical equipment. Data from Example 1 and Comparative Example 5 shows that, by adding silane-modified aluminum hydroxide, this invention can significantly reduce the combustion temperature of the thermal aerosol medium. Within the scope of this invention, the combustion temperature of the thermal aerosol extinguishing medium is less than 200°C, the extinguishing efficiency is less than 0.4 (a lower extinguishing efficiency value indicates higher extinguishing effectiveness), the solid residue rate is less than 6.5 wt%, and it exhibits low corrosivity to brass plates.

[0109] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A low-temperature and low-corrosion thermal aerosol fire extinguishing medium, characterized in that, The thermal aerosol extinguishing medium includes an oxidant and modified aluminum hydroxide; The oxidant is a mixture of strontium nitrate, potassium organic acid, and chlorate; The modified aluminum hydroxide contains 10-30 wt% silane groups. The weight ratio of the oxidant to the modified aluminum hydroxide is 1:0.01-0.

5.

2. The thermal aerosol fire extinguishing medium according to claim 1, wherein, The weight ratio of strontium nitrate, potassium organic acid, and chlorate in the oxidant is 10-20:1-4:1; The organic potassium acid is at least one of potassium oxalate, potassium citrate, potassium gluconate, potassium tartrate, and potassium acetate. The chlorate is at least one of potassium chlorate, magnesium chlorate, sodium chlorate, strontium chlorate, and ammonium chlorate.

3. The thermal aerosol fire extinguishing medium according to claim 2, wherein, The organic acid potassium is a mixture of potassium oxalate and potassium citrate; The weight ratio of potassium oxalate to potassium citrate is 5-20:

1.

4. The thermal aerosol fire extinguishing medium according to claim 1, wherein, The method for preparing the modified aluminum hydroxide includes: mixing aluminum hydroxide and a coupling agent in the presence of a first solvent, and heating and stirring; wherein the weight ratio of aluminum hydroxide to coupling agent is 1:0.1-2.

5. The thermal aerosol fire extinguishing medium according to claim 4, wherein, The coupling agent is selected from at least one of vinyltriethoxysilane, γ-aminopropyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane; The first solvent is selected from at least one of water, ethanol, methanol, and acetonitrile.

6. The thermal aerosol fire extinguishing medium according to claim 1, wherein, The thermal aerosol extinguishing medium also includes combustible agents and binders; The weight ratio of the oxidant to the combustible agent is 1:0.1-5; The weight ratio of the oxidant to the binder is 1:0.01-1.

7. The thermal aerosol fire extinguishing medium according to claim 6, wherein, The combustible agent is selected from at least one of lactose, sucrose, melamine, magnesium hydride, and lithium hydride; The adhesive is selected from at least one of phenolic resin, epoxy resin, shellac, polyvinyl alcohol, and idutol.

8. The thermal aerosol fire extinguishing medium according to claim 7, wherein, The combustible agent is a mixture of lactose and magnesium hydride; The weight ratio of lactose to magnesium hydride is 1-5:

1.

9. A method for preparing a low-temperature and low-corrosion thermal aerosol fire extinguishing medium, characterized in that, The oxidant, modified aluminum hydroxide, flammable agent and binder are mixed, and then a second solvent is added before drying.

10. The application of the thermal aerosol extinguishing medium according to any one of claims 1-8 and the thermal aerosol extinguishing medium prepared according to claim 9 in the extinguishing of fires in electrical equipment.