Chemical coolant for aerosol free extinguishing agent and preparation method

Abstract

Disclosed are a chemical coolant for an aerosol fire extinguishing agent and a preparation method. The chemical coolant is prepared by means of selecting an inorganic salt of K / Na / Mg / Ca / Sr that can undergo a decomposition reaction and combining same with an organic flame retardant and a binder. By using a metal inorganic salt, a decomposition reaction occurs at a high temperature to generate active metal substances such as K / Na / Mg / Ca / Sr oxide, and the fire extinguishing capacity is enhanced while combustion heat is absorbed. The organic flame retardant also undergoes a vaporization or decomposition reaction at a high temperature to generate a non-combustible gas such as NH3, N2, CO2, and water vapor, the aerosol content is increased while flame extinction and cooling are achieved, and the fire extinguishing capacity is enhanced. Furthermore, the organic flame retardant also has certain binding characteristics. An auxiliary binder is used for binding the chemical coolant to increase the stability, thereby preventing the metal inorganic salt in the chemical coolant from experiencing pulverization during storage, transportation, and use.

Description

CHEMICAL COOLANT FOR AEROSOL FIRE EXTINGUISHING AGENT AND PREPARATION METHOD TECHNICAL FIELD The present invention relates to the technical field of chemical coolants, in particular to a chemical coolant for aerosol fire extinguishing agents and a preparation method thereof. BACKGROUND After burning, a thermal aerosol fire extinguishing agent will produce a large amount of non-combustible gas such as N2, CO2, and water vapor, as well as solid particles of oxides like potassium and strontium; among them, the non-combustible gas can reduce the concentration of flammable gas and oxygen at a fire site, and inhibit flames, and the solid particles of oxides can capture radicals such as HO , H . and 0 , and reduce the concentration of active radicals at a fire site to achieve chemically inhibiting and extinguishing fire and perform fire-extinguishing in multiple dimensions; in addition, a thermal aerosol fire-extinguishing agent prepared with technological development becomes weaker and weaker in corrosiveness and environmental pollution, and the range of its application expands more widely. However, it is necessary for the thermal aerosol extinguishing agent to perform combustion under a strongly-exothermic reaction during extinguishing fire, and its peak temperature during spurting can reach about 1000°C, posing significant safety hazards and secondary disasters. Therefore, in order to reduce safety' risks, it is necessary to block or absorb the heat generated during the combustion of the thermal aerosol fire-extinguishing agent. Currently, the thermal aerosol fire-extinguishing agent is typically used in combination with a coolant to reduce spurting temperature. Commonly-used coolants are divided into physical coolants and chemical coolants. A Chinese patent (CN102872557B) discloses a physical cooling method that replaces chemical coolants for aerosol fire-extinguishing devices, making it possible to replace chemical coolants, so as to achieve rapid cooling and enable airflow to rapidly circulate, by way of loading physical decelerant and a physical coolant on the top of the chemicals column. A Chinese patent (CN101716404B) discloses a cooling filtration layer for thermal aerosol fire-extinguishing devices, making it possible for chemical coolants to participate in reactions without damaging structural layers of a cooling module, by way of loading the chemical coolants onto the cooling module. An US Patent (US20120273714A1) discloses a catalytic chemical coolant for aerosol and a preparation method thereof, wherein the catalytic chemical coolant is prepared by way of using endothermic cooling materials such as manganese oxalate and potassium permanganate, metal oxides or hydroxides, processing aids such as stearates, and binders composed of alkaline metal silicates and water-soluble polymers in solution, and further includes a surface coating agent made from hydroxymethyl or hydroxyethyl cellulose films. The catalytic chemical coolant has higher strength, better cooling performance, and eliminates toxic gases produced from the fire-extinguishing agents. A Chinese patent (CN110755776B) discloses an assembly method for thermal aerosol coolants and thermal aerosol generating agents, making it possible for the thermal aerosol coolant to promptly and fully exert its heat-absorbing and cooling effect when an strongly-exothermic reaction occurs to the thermal aerosol generating agent and reduce the impact on performance of combustion and injection, by way of combining or individually using physical coolants such as cast iron, ceramics, an graphite and chemical coolants such as alkaline magnesium carbonate and calcium carbonate. However, the chemical coolants currently prepared for aerosol fire-extinguishing agents only specialize in functions such as extinguishing flames and cooling, while the large amount of heat generated during the extinguishing process is not fully utilized, resulting in wasting energy to a certain extent. SUMMARY OF THE INVENTION In order to address the above technical problem, an objective of the present invention is to provide a chemical coolant for aerosol fire extinguishing agents and a preparation method thereof, so as to make it possible to raise ability to extinguish fire and enable flames to be extinguished and temperature to drop, by way of preparing a new chemical coolant based on the idea that thermal aerosol fire-extinguishing agents generate a large amount of heat during burning and spurting and such heat is fully utilized to produce a new aerosol capable of fire-extinguishing. In order to achieve the above objective, a chemical coolant for aerosol fire extinguishing agents consists of 30%-69% of organic flame retardants, 30%-69% of metallic inorganic salts, and 1 %-l 0% of binders, based on 100 percent by weight. Preferably, the organic flame retardant is any one of dicyandiamide, melamine, melamine cyanurate, melamine phosphate, melamine borate, poly-melamine pyrophosphate, and melamine pyrophosphate. Preferably, the metal inorganic salt is an inorganic salt of K / Na / Mg / Ca / Sr capable of reacting for decomposition. Preferably, the inorganic salt of K / Na / Mg / Ca / Sr capable of reacting for decomposition is any one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, magnesium carbonate, magnesium bicarbonate, calcium carbonate, calcium bicarbonate, strontium carbonate, and strontium bicarbonate. Preferably, the binder is any one of ethyl cellulose, phenolic resin, epoxy resin, hydroxypropyl methylcellulose, polyvinyl alcohol and dextrin. Hie present invention also provides a method for preparing a chemical coolant for aerosol fire extinguishing agents, specifically including the following steps. (1) Weighing an organic flame retardant, a metal inorganic salt, and a binder, then sieving and blending them by means of a sieve several times to obtain a mixture; (2) Adding anhydrous methanol to the mixture, then blending them to obtain a wet material; (3) Granulating the wet material through a sieve to obtain wet coolant particles, then drying the wet coolant particles to obtain dry coolant particles, next sieving the dry coolant particles by means of a sieve 2 times to obtain coolant particles; and (4) Pressing the coolant particles to obtain a coolant product. Preferably, the sieve defined in step (1) is a 100-mesh sieve, and the process of sieving the organic flame retardant, the metal inorganic salt, and the binder is executed 3-5 times. Preferably, the anhydrous methanol defined in step (2) accounts for 10-20% of the total weight of the mixture. Preferably, the sieve defined in step (3) is a 20-mesh sieve, and the process of drying the wet coolant particles is executed at 55-65°C for 12-24 hours until a volatile content is less than 1%. Preferably, the process of pressing the coolant particles in step (4) is executed under 10 MPa, and the coolant product has a diameter of 6 mm and a thickness of 5.5 mm. The present invention has the following beneficial effects: The inorganic salt of K / Na / Mg / Ca / Sr capable of reacting for decomposition that is used as a main component of the coolant, can generate active metal substances for extinguishing fire while undergoing an endothermic decomposition reaction, and raise the ability for the aerosol fire-extinguishing agent to extinguish fire while extinguishing flames and cooling. In addition, a thermal decomposition reaction also occurs at about 300°C to the organic flame retardant used in combination and absorbs heat while producing non-flammable gas such as NH3, N2, CO2, and water vapor, making it possible to reduce the concentration of flammable gas and oxygen and cover flames, raising the ability to cool and extinguish fire. Furthermore, the selected organic flame retardants also have a certain cohesiveness, and are used in combination with the binders to bind the metal inorganic salts, making it possible to enhance the cohesiveness of the chemical coolant, prevent the metal inorganic salts from pulverizing, and improve tire stability of the chemical coolant during storage, transportation, and use, thereby ensuring an effect of cooling the aerosol fire-extinguishing agent. DETAILED DESCRIPTION We shall further describe the technical solutions of the present invention in combination with the figures and specific embodiments. It should be noted that the following examples are only some preferred embodiments of the present invention and should not be understood as any limitations imposed on the present invention. The protection scope of the present invention shall be defined by the claims. Any modifications or substitutions to the technical solutions of the present invention made by a person skilled in the art without any inventive work fall within the protection scope of the present invention. EXAMPLE 1 (1) Weighing 50% of potassium carbonate, 45% of dicyandiamide, and 5% of phenolic resin, which have a particle size less than 100 mesh, then sieving and blending them by means of a 100-mesh sieve 3 times to obtain a mixture. (2) Adding 14% anhydrous methanol to the mixture, then blending them to obtain a wet material. (3) Granulating the wet material through a 20-mesh sieve to obtain wet coolant particles, then drying the wet coolant particles at 55-65°C for 12-24 hours until a volatile content is less than 1% to obtain coolant particles. (4) Putting the coolant particles in a tablet press and pressing them under 10 MPa to obtain a coolant product having a diameter of 6 mm and a thickness of 5.5 mm. EXAMPLE 2 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of potassium bicarbonate, 45% of melamine, and 5% of ethyl cellulose, which are used for preparation to obtain a chemical coolant product. EXAMPLE 3 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of sodium carbonate, 45% of melamine cyanurate, and 5% of epoxy resin, which are used for preparation to obtain a chemical coolant product. EXAMPLE 4 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of sodium bicarbonate, 45% of melamine phosphate, and 5% of polyvinyl alcohol, which are used for preparation to obtain a chemical coolant product. EXAMPLE 5 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of magnesium carbonate, 45% of poly-melamine pyrophosphate, and 5% of hydroxypropyl methylcellulose, which are used for preparation to obtain a chemical coolant product. EXAMPLE 6 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of magnesium bicarbonate, 45% of melamine, and 5% of dextrin, which are used for preparation to obtain a chemical coolant product. EXAMPLE 7 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of potassium carbonate, 45% of dicyandiamide, and 5% of ethyl cellulose, which are used for preparation to obtain a chemical coolant product. EXAMPLE 8 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 50% of magnesium bicarbonate, 45% of dicyandiamide, and 5% of ethyl cellulose, which are used for preparation to obtain a chemical coolant product. EXAMPLE 9 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 30% of potassium carbonate, 60% of dicyandiamide, and 10% of phenolic resin, which are used for preparation to obtain a chemical coolant product. EXAMPLE 10 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 69% of potassium carbonate, 30% of dicyandiamide, and 1% of phenolic resin, which are used for preparation to obtain a chemical coolant product. CONTROL 1 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 95% of dicyandiamide, and 5% of ethyl cellulose, which are used for preparation to obtain a chemical coolant product. CONTROL 2 The method and steps are the same as those in Example 1. except that the raw materials are replaced with 99% of melamine and 1% of phenolic resin, which are used for preparation to obtain a chemical coolant product. CONTROL 3 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 95% of potassium carbonate and 5% of dextrin, which are used for preparation to obtain a chemical coolant product. CONTROL 4 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 80% of potassium carbonate and 20% of dextrin, which are used for preparation to obtain a chemical coolant product. CONTROL 5 Tire method and steps are the same as those in Example 1, except that the raw materials are replaced with 20% of sodium bicarbonate, 79% of dicyandiamide, and 1% of dextrin, which are used for preparation to obtain a chemical coolant product. CONTROL 6 The method and steps are the same as those in Example 1, except that the raw materials are replaced with 79% of sodium bicarbonate, 20% of dicyandiamide, and 1% of dextrin, which are used for preparation to obtain a chemical coolant product. Result Detection: Weighing 70g of the chemical coolant product obtained in Examples 1-10 and Controls 1-6 and 70g of physical coolants (ceramic balls with ¢6), then assembling them with 50g of chemicals columns of a K-type aerosol fire-extinguishing agents (homemade, 73% of KNOs and 27% of reducing agents) to form a small fire-extinguishing device respectively, then conducting a spurting experiment, and measuring the device's weight before and after the experiment to determine a released quantity based on a weight difference; at the same time, measuring the temperature at 0.5 cm from the nozzle of the device during the spurting experiment. Placing the chemical coolant products prepared in Examples 1-10 and Controls 1-5 at 85% humidity and 25°C for a high-humidity test, then observing and recording situations that the chemical coolant products have been pulverized after 12 hours, 24 hours, and 1 week. The results are shown in the table as follows. Released quantity / g Spurting temperature / °C Fire-extinguishin g time / s Pulverization Example 1 103.2 364 21 Not pulverized after 1 week. Example 2 104.5 357 20 Not pulverized after 1 week. Example 3 102.6 347 25 Not pulverized after 1 week. Example 4 101.8 362 24 Not pulverized after 1 week. Example 5 105.1 346 30 Not pulverized after 1 week. Example 6 103.7 368 31 Not pulverized after 1 week. Example 7 103.9 354 19 Not pulverized after 1 week. Example 8 105.9 348 32 Not pulverized after 1 week. Example 9 104.2 343 27 Not pulverized after 1 week. Example 10 106.2 347 20 Not pulverized after 1 week. Control 1 109.6 650 Not extinguished after 300s Not pulverized after 1 week. Control 2 108.7 664 Not extinguished after 300s Not pulverized after 1 week. Control 3 95.2 345 34 Pulverized after 12 hours. Control 4 105.2 354 40 Pulverized after 1 week. Control 5 100.5 475 52 Pulverized after 1 week. Control 6 103.4 351 27 Pulverized after 24 hours. physical coolant 45.3 704 Not extinguished after 300s - Hie results are shown in Table 1. Compared with physical coolants, the chemical coolants prepared in Examples 1-10 present a lower spurting temperature, a shorter fire-extinguishing time, and a higher released quantity during the spurting experiment; in addition, after the high-humidity test, die chemical coolant products have not been pulverized, and their storage durability gets improved. In Controls 1-2, the organic flame retardants used as an effective component of the chemical coolant, do not contain any metal inorganic salts; although the released quantity is higher than that of Examples 1-10, the spurting temperature is noticeably increased, posing a poor cooling effect and failure to extinguish fire. In Controls 3-4, the metal organic salts used as an effective component of the chemical coolant, do not contain any organic flame retardants; although they have good effects of cooling and fire-extinguishing, they are prone to pulverization. In Controls 5-6, the chemical coolant is prepared by using the metal inorganic salts whose content is excessively low or high; among them, the chemical coolant prepared by using the metal inorganic salts whose content is high presents a better effect of cooling and fire-extinguishing, while the chemical coolant prepared by using the metal inorganic salts whose content is low presents a comparatively-poorer effect of cooling and fire-extinguishing; in addition, both types of coolants are prone to pulverization, and the higher the content of the inorganic salts, the more likely pulverization occurs.

Claims

1. A chemical coolant for aerosol fire extinguishing agents consisting of 30%-69% of organic flame retardants, 30%-69% of metallic inorganic salts, and l%-10% of binders, based on 100 percent by weight.

2. The chemical coolant for aerosol fire extinguishing agents according to claim 1, wherein the organic flame retardant is any one of dicyandiamide, melamine, melamine cyanurate, melamine phosphate, melamine borate, poly-melamine pyrophosphate, and melamine pyrophosphate.

3. Tire chemical coolant for aerosol fire extinguishing agents according to claim 1, wherein the metal inorganic salt is an inorganic salt of K / Na / Mg / Ca / Sr capable of reacting for decomposition.

4. The chemical coolant for aerosol fire extinguishing agents according to claim 3, wherein the inorganic salt of K / Na / Mg / Ca / Sr capable of reacting for decomposition is anyone of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, magnesium carbonate, magnesium bicarbonate, calcium carbonate, calcium bicarbonate, strontium carbonate, and strontium bicarbonate.

5. The chemical coolant for aerosol fire extinguishing agents according to claim 1, wherein the binder is any one of ethyl cellulose, phenolic resin, epoxy resin, hydroxypropyl methylcellulose, polyvinyl alcohol and dextrin.

6. A method for preparing the chemical coolant for aerosol fire extinguishing agents claimed in any one of claims 1-5, comprising the steps of(1) weighing an organic flame retardant, a metal inorganic salt, and a binder, then sieving and blending them by means of a sieve several times to obtain a mixture;(2) adding anhydrous methanol to tire mixture, then blending them to obtain a wet material;(3) granulating the wet material through a sieve to obtain wet coolant particles, then drying the wet coolant particles to obtain dry coolant particles, next sieving the dry coolant particles by means of a sieve 2 times to obtain coolant particles; and(4) pressing the coolant particles to obtain a coolant product.

7. The method according to claim 6, wherein the sieve defined in step (1) is a 100-mesh sieve, and the process of sieving the organic flame retardant, the metal inorganic salt, and the binder is executed 3-5 times.

8. The method according to claim 6, wherein the anhydrous methanol defined in step (2) accounts for 10-20% of the total weight of the mixture.

9. The method according to claim 6. wherein the sieve defined in step (3) is a 20-mesh sieve, and the process of drying the wet coolant particles is executed at 55-65°C for 12-24 hours until a volatile content is less than 1%.

10. The method according to claim 6, wherein the process of pressing the coolant particles in step (4) is executed under 10 MPa, and the coolant product has a diameter of 6 mm and a thickness of 5.5 mm.