Chemical coolant for aerosol fire extinguishing agent and preparation method thereof

Abstract

The invention discloses a chemical coolant for an aerosol fire extinguishing agent and a preparation method thereof. The chemical coolant is prepared by selecting K / Na / Mg / Ca / Sr inorganic salts capable of undergoing decomposition reactions, combining them with an organic flame retardant and a binder. The metal inorganic salts undergo decomposition reactions at high temperatures to produce active metal substances such as K / Na / Mg / Ca / Sr oxides, thereby improving the fire extinguishing capability while absorbing combustion heat. The organic flame retardant also undergoes vaporization or decomposition reactions at high temperatures to produce non-combustible gases such as NH3, N2, CO2, and water vapor, thereby extinguishing flames and lowering temperatures while increasing the content of the aerosol and improving the fire extinguishing capability. Meanwhile, the organic flame retardant also has certain bonding properties, and the auxiliary binder is used to bond the chemical coolant, thereby improving stability and preventing the metal inorganic salts in the chemical coolant from pulverizing during storage, transportation, and use.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical coolants, and in particular relates to a chemical coolant for an aerosol fire extinguishing agent and a preparation method thereof. Background Art

[0002] After the thermal aerosol fire extinguishing agent burns, it will produce a large amount of non-combustible gases such as N2, CO2 and water vapor, as well as solid oxide particles such as potassium and strontium. The non-combustible gas can reduce the concentration of combustible gas and oxygen in the fire scene and suppress the flame; while the oxide solid particles can capture HO·, H· and O· free radicals, reduce the concentration of active free radicals in the fire scene to achieve chemical suppression fire extinguishing, and extinguish fire in multiple dimensions. With the development of technology, the corrosiveness and environmental pollution of the prepared thermal aerosol fire extinguishing agent are getting smaller and smaller, and its application range is becoming more and more extensive. However, the thermal aerosol fire extinguishing agent needs to burn when extinguishing a fire, which is a strong exothermic reaction. When spraying, its maximum temperature can reach about 1000℃, causing great safety hazards and secondary disasters. Therefore, in order to reduce safety hazards, it is necessary to block or absorb the heat generated during the combustion of the thermal aerosol fire extinguishing agent.

[0003] At present, a method of using a hot aerosol fire extinguishing agent in combination with a coolant to reduce the spraying temperature is generally adopted. Commonly used coolants are divided into physical coolants and chemical coolants. Chinese patent CN102872557B discloses a physical cooling method for replacing the chemical coolant of an aerosol fire extinguishing device. By installing a physical deceleration agent and a physical coolant above the cartridge, the chemical coolant is replaced to achieve rapid cooling and ensure rapid circulation of airflow; Chinese patent CN101716404B discloses a cooling filter layer of a hot aerosol fire extinguishing equipment, and a chemical coolant is loaded on the cooling layer module, so that the chemical coolant does not damage the structural layer of the cooling module when participating in the reaction. US Patent US20120273714A1 discloses a catalytic chemical coolant for aerosol and a preparation method thereof, wherein the catalytic chemical coolant is prepared by using heat absorbing cooling materials such as manganese oxalate and potassium permanganate, metal oxides or hydroxides, processing aids such as stearates, and a binder of alkali metal silicate and water-soluble polymers in accordance with the composition of the solution, and further comprising a surface coating agent made of hydroxymethyl or hydroxyethyl cellulose film, and the catalytic chemical coolant has high strength and good cooling effect and eliminates toxic gases in the fire extinguishing agent product. Chinese Patent CN110755776B discloses an assembly method for a hot aerosol coolant and a hot aerosol generator, wherein the cast iron, ceramic or graphite physical coolant and chemical coolants such as basic magnesium carbonate and calcium carbonate are combined or used alone, so that the hot aerosol coolant can timely and fully exert the heat absorbing and cooling effect when the hot aerosol generator undergoes a strong exothermic reaction, thereby reducing the impact on the combustion injection performance.

[0004] However, the chemical coolants currently prepared for hot aerosol fire extinguishing agents only take into account their flame extinguishing and temperature reducing functions, while the large amount of heat generated during the fire extinguishing process is not fully utilized, resulting in a certain amount of energy waste. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a chemical coolant for aerosol fire extinguishing agent and a preparation method thereof. According to the idea that a large amount of heat will be generated during the combustion and spraying process of hot aerosol fire extinguishing agent, and the heat is fully utilized to produce a new aerosol with fire extinguishing ability, a new chemical coolant is prepared, which can improve the fire extinguishing ability while ensuring the flame extinguishing and cooling effect.

[0006] In order to achieve the above object, the present invention provides a chemical coolant for aerosol fire extinguishing agent, which is composed of 30%-69% organic flame retardant, 30%-69% metal inorganic salt and 1%-10% binder.

[0007] Preferably, the organic flame retardant is any one of dicyandiamide, melamine, melamine cyanurate, melamine orthophosphate, melamine borate, melamine phosphate or melamine pyrophosphate.

[0008] Preferably, the metal inorganic salt is a K / Na / Mg / Ca / Sr inorganic salt that can undergo a decomposition reaction.

[0009] Preferably, the inorganic salt of K / Na / Mg / Ca / Sr that can undergo decomposition reaction is any one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, magnesium carbonate, magnesium bicarbonate, calcium carbonate, calcium bicarbonate, strontium carbonate or strontium bicarbonate.

[0010] Preferably, the binder is any one of ethyl cellulose, phenolic resin, epoxy resin, hydroxypropyl methyl cellulose, polyvinyl alcohol or dextrin.

[0011] The present invention also provides a method for preparing a chemical coolant for an aerosol fire extinguishing agent, which specifically comprises the following steps:

[0012] (1) weighing an organic flame retardant, a metal inorganic salt, and a binder, sieving and mixing them multiple times to obtain a mixture;

[0013] (2) adding anhydrous methanol to the mixture and mixing to obtain a wet material;

[0014] (3) sieving the wet material into granules, and then drying and sieving it again to obtain coolant granules;

[0015] (4) The coolant particles are pressed to obtain a coolant product.

[0016] Preferably, the sieve in step (1) is 100 mesh, and the sieving times are 3-5 times.

[0017] Preferably, the mass of the anhydrous methanol in step (2) accounts for 10-20% of the mass of the mixture.

[0018] Preferably, the sieve in step (3) is 20 mesh, and the drying condition is 55-65° C. for 12-24 hours until the volatile content is less than 1%.

[0019] Preferably, the pressing condition in step (4) is 10 MPa, and the diameter of the finished coolant product is 6 mm and the height is 5.5 mm.

[0020] The beneficial effects of the present invention are: using K / Na / Mg / Ca / Sr inorganic salts that can undergo decomposition reactions as the main components of the coolant, the endothermic decomposition reaction produces fire-extinguishing active metal substances, and the fire-extinguishing ability of the aerosol fire extinguishing agent is improved while eliminating smoke and cooling. The organic flame retardant used in combination also undergoes a thermal decomposition reaction at around 300°C to absorb heat, and produces non-combustible gases such as NH3, N2, CO2, and water vapor, which can reduce the concentration of combustible gas and oxygen and cover the flame, thereby enhancing the cooling ability and fire-extinguishing ability; in addition, the selected organic flame retardant also has a certain degree of adhesion, and cooperates with the adhesive to bond the metal inorganic salt, thereby improving the adhesion of the chemical coolant, avoiding the pulverization of the metal inorganic salt, and improving the stability of the finished chemical coolant during storage, transportation and use, thereby ensuring the cooling effect of the aerosol fire extinguishing agent. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further explained below in conjunction with specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The protection scope of the present invention shall be subject to the contents recorded in the claims. Any modification or replacement made by a person skilled in the art to the technical solution of the present invention without creative work shall fall within the protection scope of the present invention.

[0022] Example 1

[0023] (1) Weighing 50% potassium carbonate, 45% dicyandiamide and 5% phenolic resin with a mesh size less than 100, passing through a 100-mesh sieve three times, dry-mixing and mixing to obtain a mixture;

[0024] (2) Weighing 14% anhydrous methanol and adding it to the mixture, mixing evenly to obtain a wet material;

[0025] (3) passing the wet material through a 20-mesh screen to granulate, and then drying at 55° C. for 12 h to 24 h until the volatile content is less than 1%, thereby obtaining chemical coolant granules;

[0026] (4) The coolant particles are placed in a tablet press and pressed at 10 MPa to obtain a chemical coolant product with a diameter of 6 mm and a height of 5.5 mm. The finished product is in a cylindrical shape.

[0027] Example 2

[0028] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% potassium bicarbonate, 45% melamine and 5% ethyl cellulose to prepare a finished chemical coolant.

[0029] Example 3

[0030] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% sodium carbonate, 45% melamine cyanurate and 5% epoxy resin to prepare a finished chemical coolant.

[0031] Example 4

[0032] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% sodium bicarbonate, 45% melamine orthophosphate and 5% polyvinyl alcohol to prepare a finished chemical coolant.

[0033] Example 5

[0034] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% magnesium carbonate, 45% focused melamine phosphate and 5% hydroxypropyl methylcellulose to prepare a finished chemical coolant.

[0035] Example 6

[0036] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% magnesium bicarbonate, 45% melamine and 5% dextrin to prepare a finished chemical coolant.

[0037] Example 7

[0038] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% potassium carbonate, 45% dicyandiamide and 5% ethyl cellulose to prepare a finished chemical coolant.

[0039] Example 8

[0040] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 50% magnesium hydroxide, 45% dicyandiamide and 5% ethyl cellulose to prepare a finished chemical coolant.

[0041] Example 9

[0042] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 30% potassium carbonate, 60% dicyandiamide and 10% phenolic resin to prepare a finished chemical coolant.

[0043] Example 10

[0044] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 69% potassium carbonate, 30% dicyandiamide and 1% phenolic resin to prepare a finished chemical coolant.

[0045] Comparative Example 1

[0046] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 95% dicyandiamide and 5% ethyl cellulose to prepare a finished chemical coolant.

[0047] Comparative Example 2

[0048] The method and steps are the same as those in Example 1, wherein the raw materials are replaced with 99% melamine and 1% phenolic resin to prepare a finished chemical coolant.

[0049] Comparative Example 3

[0050] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 95% potassium carbonate and 5% dextrin to prepare a finished chemical coolant.

[0051] Comparative Example 4

[0052] The method and steps are the same as those in Example 1, wherein the raw materials are replaced with 80% potassium carbonate and 20% dextrin to prepare a finished chemical coolant.

[0053] Comparative Example 5

[0054] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 20% sodium bicarbonate, 79% dicyandiamide and 1% dextrin to prepare a finished chemical coolant.

[0055] Comparative Example 6

[0056] The method and steps are the same as those of Example 1, wherein the raw materials are replaced with 79% sodium bicarbonate, 20% dicyandiamide and 1% dextrin to prepare a finished chemical coolant.

[0057] Results test:

[0058] Take the finished chemical coolant and physical coolant (Φ6 ceramic ball) prepared in Examples 1-10 and Comparative Examples 1-6, respectively, and 50g of K-type aerosol fire extinguishing agent (homemade, 73% KNO3 + 27% reducing agent) to assemble into a small fire extinguishing device, and conduct a spraying experiment. The device weight is weighed before and after the experiment, and the spraying amount is obtained by the weight difference before and after. At the same time, the temperature at 0.5cm away from the nozzle of the device is tested during the spraying experiment.

[0059] The finished chemical coolants prepared in Examples 1-10 and Comparative Examples 1-5 were placed under a high humidity test at a humidity of 85% and a temperature of 25° C. The powdering of the finished chemical coolants was observed and recorded after 12 h, 24 h and 1 week.

[0060] The results are shown in the table below:

[0061]

[0062]

[0063] The results are shown in Table 1: Compared with the physical coolant, the chemical coolant prepared in Examples 1-10 has a lower spraying temperature, a shorter fire extinguishing time and a higher spraying amount when conducting the spraying experiment, and after the high humidity experiment, the finished chemical coolant does not pulverize, and the storage resistance is improved. However, Comparative Examples 1 and 2 all use organic flame retardants as the effective ingredients of chemical coolants, and do not contain metal inorganic salts. Although the spraying amount is increased compared with Comparative Examples 1-10, the spraying temperature is significantly increased, the cooling effect is poor, and the fire extinguishing fails. Comparative Examples 3 and 4 all use metal organic salts as the effective ingredients of chemical coolants without adding organic flame retardants. Although they all have good cooling and fire extinguishing effects, they are prone to pulverization. Comparative Examples 5 and 6 use chemical coolants prepared by using metal inorganic salts with too low or too high content, respectively. The coolant with a high content of metal inorganic salt has better cooling and fire extinguishing effects, while the coolant with a low content of metal inorganic salt has relatively poor cooling and fire extinguishing effects. Both coolants are prone to pulverization, and the higher the inorganic salt content, the more prone to pulverization.

Claims

1. A chemical coolant for an aerosol fire extinguishing agent, characterized in that: It is composed of 30%-69% organic flame retardant, 30%-69% metal inorganic salt and 1%-10% binder; The organic flame retardant is any one of dicyandiamide, melamine, melamine cyanurate, melamine orthophosphate, melamine borate, focused melamine phosphate or melamine pyrophosphate; The metal inorganic salt is a K / Na / Mg inorganic salt that can undergo a decomposition reaction; The K / Na / Mg inorganic salt capable of undergoing a decomposition reaction is any one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, magnesium carbonate or magnesium bicarbonate.

2. The chemical coolant for an aerosol fire extinguishing agent according to claim 1, characterized in that: The binder is any one of ethyl cellulose, phenolic resin, epoxy resin, hydroxypropyl methyl cellulose, polyvinyl alcohol or dextrin.

3. A method for preparing a chemical coolant for an aerosol fire extinguishing agent comprising the chemical coolant for an aerosol fire extinguishing agent according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Weighing an organic flame retardant, a metal inorganic salt and a binder, sieving and mixing them several times to obtain a mixture; (2) adding anhydrous methanol to the mixture and mixing to obtain a wet material; (3) Screening the wet material into granules, and then drying and screening it again to obtain coolant granules; (4) The coolant particles are pressed to obtain a coolant product.

4. The preparation method according to claim 3, characterized in that: The sieve of step (1) has a mesh size of 100 and is screened 3-5 times.

5. The preparation method according to claim 3, characterized in that: The mass of the anhydrous methanol described in step (2) accounts for 10-20% of the mass of the mixture.

6. The preparation method according to claim 3, characterized in that: The mesh size of the sieve in step (3) is 20 mesh, and the drying condition is drying at 55-65° C. for 12-24 hours until the volatile content is less than 1%.

7. The preparation method according to claim 3, characterized in that: The pressing condition in step (4) is 10 MPa, and the diameter of the finished coolant is 6 mm and the height is 5.5 mm.

Images