Fluorine-free gel foam extinguishing agent and preparation method thereof

Abstract

The invention discloses a fluoride-free gel foam extinguishing agent and a preparation method thereof. The fluoride-free gel foam extinguishing agent is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water. The weight percentage of each component is as follows: 0.1-3% of the composite foaming agent, 0.1-5% of the composite gelling agent, 0.1-1% of the cross-linking agent, 3-5% of the flame retardant and the balance of water. The preparation method of the fluoride-free gel foam extinguishing agent comprises the following steps: S1, preparing the foam component; s2, preparing a gel component; and S3, the foam component and the gel component are mixed and stirred to be uniform, the mixture is poured into a foaming device to be subjected to foaming operation, and then the fluoride-free gel foam extinguishing agent is obtained. The konjaku flour and the xanthan gum in the fire extinguishing agent have a cross-linking effect with aluminum citrate to form a stable three-dimensional cross-linked network structure, so that the stability and the water retention capacity of foam are improved, a good synergistic effect is achieved, and the fire extinguishing effect is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of fire extinguishing, in particular to a fluorine-free gel foam fire extinguishing agent and a preparation method thereof. Background Art

[0002] Coal, a vital global energy source and chemical raw material, boasts abundant reserves and widespread distribution, making it the primary energy source for many countries. However, coal mining faces numerous challenges, including frequent gas explosions, fires, and water inrush. In particular, mine fires are often caused by the spontaneous combustion of residual coal. These challenges not only limit safe coal mining but also pose a serious threat to the lives of miners. To reduce the incidence of spontaneous coal combustion, researchers worldwide have proposed a variety of technologies, including grouting, inert gas injection, retardants, foams, and gels, but each has its limitations. Gel firefighting technology has attracted widespread attention due to its excellent sealing and water retention properties. However, gels have poor fluidity and diffusivity and are prone to cracking. Foam firefighting technology, on the other hand, offers excellent fluidity and packing properties, but is prone to water loss and lacks stability. To overcome the shortcomings of these two technologies, gel-foam technology has emerged.

[0003] Gel foam is composed of a blowing agent, a gelling agent, a cross-linking agent, and other auxiliary ingredients. Its formation process can be divided into two stages: first, surfactant molecules form a foam at the gas-liquid interface; then, the liquid film, through the action of the gelling agent and cross-linking agent, forms a stable three-dimensional network structure, thereby enhancing the foam's stability and limiting the drainage of the liquid film and the diffusion of gases. Gel foam exhibits good fluidity before gelation and excellent water retention and cooling properties after gelation. This effectively overcomes the shortcomings of traditional water-based foams, such as easy breakage and rapid water loss, while also compensating for the poor diffusivity of gel technology. Therefore, gel foam technology not only has greater stability but also improves fire prevention and extinguishing effectiveness.

[0004] The invention patent with the publication number of "CN118543065 B" discloses a solid gel foam fire extinguishing agent and its preparation method. The gel foam can form a semi-gel state inside the pipeline and during the spraying process, and can quickly adhere to the fire extinguishing object to form a solid gel. It has the advantages of low density, low oil infiltration, low resistance, high adhesion, fire resistance and difficult defoaming. However, too fast gelation is extremely unfavorable for long pipeline transportation, and it is easy to accumulate in the pipeline and cause blockage. The invention patent with the publication number of "CN116284987 B" discloses a bio-based composite gel foam fire extinguishing agent and its preparation method. The prepared biomass-based composite gel foam has excellent biodegradability and biocompatibility, high specific strength, small pore size, and density as low as 0.7g / cm 3, but the foaming multiple is low, making it difficult to achieve large-area coverage and efficient barrier. The invention patent with the patent publication number "CN119113468 A" discloses a gel foam for preventing coal spontaneous combustion. The gel foam has excellent water retention, but the gelling agent mass percentage of the gel foam is relatively high, and no flame retardant and antioxidant are added. The flame retardant effect of the foam under high temperature conditions is limited and it is easy to break and collapse. The invention patent with the patent publication number "CN110124244 A" discloses a Class A foam based on a C4 twin-type fluorinated surfactant. The Class A foam fire extinguishing agent can effectively control the re-ignition of solid combustibles, greatly reduce the operating intensity, and improve the on-site fire extinguishing efficiency, but the foam contains fluorinated surfactants, which have certain pollution to the environment. The invention patent with patent publication number "CN101265811 A" discloses a method for preparing a multi-phase gel foam for preventing and controlling coal spontaneous combustion. The gel foam uses fly ash slurry, which has a relatively complex composition. After breaking the gel, a large amount of solid particulate pollutants will remain, and there is a problem of the gelation time being too long or too short.

[0005] In summary, the stability of the single gel network structure of gel foam still has major shortcomings, and foam drainage and coarsening problems are very likely to occur. In addition, the fluorine components in the foam fire extinguishing agent are not easy to degrade naturally, which will seriously harm the environment. It is necessary to improve it. Summary of the Invention

[0006] The purpose of the present invention is to provide a fluorine-free gel foam fire extinguishing agent with scientific formula design, good thermal stability, long water retention time, good wrapping and sealing effect, and significant effect of inhibiting spontaneous combustion of coal, and a preparation method thereof, in order to solve the above problems.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] A fluorine-free gel foam fire extinguishing agent comprises a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the weight percentages of the components are as follows: composite foaming agent 0.1-3%, composite gelling agent 0.1-5%, cross-linking agent 0.1-1%, flame retardant 3-5%, and the balance is water.

[0009] Furthermore, the weight percentages of the components in the fluorine-free gel foam fire extinguishing agent are: composite foaming agent 1.8%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0010] Furthermore, the composite foaming agent is prepared by compounding two or three of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside; the mass ratio of the sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside is 1:0.8 to 1:0.6 to 0.8.

[0011] Furthermore, the composite gelling agent is prepared from konjac flour and xanthan gum; the mass ratio of the konjac flour to the xanthan gum is 3 to 4:1.

[0012] Furthermore, the cross-linking agent is aluminum citrate.

[0013] Furthermore, the flame retardant is dimethyl methylphosphonate.

[0014] A method for preparing a fluorine-free gel foam fire extinguishing agent comprises the following steps:

[0015] S1, preparing a foam component;

[0016] S2, preparing gel components;

[0017] S3. Mix the foam component and the gel component and stir them evenly, pour them into a foaming device for foaming to obtain a fluorine-free gel foam fire extinguishing agent.

[0018] Furthermore, the step S1 includes the following steps:

[0019] S11. Weigh dimethyl methylphosphonate in proportion, add it to a beaker filled with water, stir evenly and allow the dimethyl methylphosphonate to completely dissolve;

[0020] S12. Weigh sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside in proportion, pour them into a beaker containing dimethyl methylphosphonate in sequence, and stir evenly to obtain a foam component.

[0021] Furthermore, step S2 includes the following steps:

[0022] S21. Weigh aluminum citrate in proportion, add it to a beaker filled with water, and stir evenly;

[0023] S22. Weigh konjac flour and xanthan gum in proportion, slowly add them to the beaker containing aluminum citrate while stirring during the addition process to obtain a gel component.

[0024] Compared with the prior art, the present invention has the following advantages and positive effects:

[0025] 1. The sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside components of the composite foaming agent and the konjac flour and xanthan gum components of the composite gelling agent of the present invention do not contain any fluorine components, are easily degraded, and meet environmental protection requirements;

[0026] 2. The konjac flour and xanthan gum in the present invention are cross-linked with aluminum citrate to form a stable three-dimensional cross-linked network structure, which greatly improves the mechanical properties, thermal stability and deformation resistance of the gel foam, effectively increases the resistance to the flow of the foam solution, and slows down the drainage rate and coarsening rate of the foam, improves the stability and water retention capacity of the foam, has good synergy, and enhances the fire extinguishing effect.

[0027] 3. The gelled foam produced in the present invention can still maintain its structural integrity when facing continuous burning of a high-temperature fire source as high as 1300°C or above, and will not collapse. At the same time, it will not burn itself, nor provide combustion-supporting conditions for combustion, and has an excellent inhibitory effect on coal spontaneous combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a diagram showing the carbonization of the fire area of the gel foam after it was burned for 2 minutes;

[0030] Figure 2 This is a microscopic morphology of the coal sample covered with the gel foam prepared in Example 2;

[0031] Figure 3 is the TG-DTG curve of raw coal;

[0032] Figure 4 This is the TG-DTG curve of the coal sample after 336 hours of gel foam action. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts, any modifications, equivalent replacements, improvements, etc., shall be included in the scope of protection of the present invention.

[0034] The present invention discloses a fluorine-free gel foam fire extinguishing agent, wherein the raw materials of the fluorine-free gel foam fire extinguishing agent are composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water;

[0035] The mass percentage of the composite foaming agent in the fire extinguishing agent is 0.1-3%. The composite foaming agent is prepared by compounding two or three of sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (LAS-30), and decyl glucoside (APG0814), with a mass ratio of 1:0.8 to 1:0.6-0.8.

[0036] The function of the composite foaming agent is to produce abundant foam while reducing the surface tension of water, so that the foam can spread quickly on the coal body, thereby achieving rapid and efficient fire extinguishing.

[0037] The mass percentage of the composite gelling agent in the fire extinguishing agent is 0.1-5%. The composite gelling agent is prepared by compounding konjac flour and xanthan gum in a mass ratio of 3-4:1. Both konjac flour and xanthan gum are soluble polysaccharide polymer compounds with long-chain structures.

[0038] The composite gelling agent forms a stable gel skeleton structure and reacts with the cross-linking agent to form a more stable three-dimensional network gel structure, enhancing the stability of the foam. Both the konjac glucomannan and xanthan gum molecules in konjac flour have long chain structures in aqueous solution. During dissolution, these chains interpenetrate and entangle with each other, forming a preliminary physical network structure that provides the basic framework for the formation of gel foam. Furthermore, the konjac glucomannan molecular chains contain a large number of hydroxyl groups, and the side chains of xanthan gum molecules also have numerous hydroxyl and carboxyl groups that can form hydrogen bonds. These groups can form hydrogen bonds with water molecules, forming a hydration film around the molecules. The polar groups on the konjac flour and xanthan gum chains also form intermolecular hydrogen bonds, further strengthening the interactions between the molecular chains, making the physical network structure more stable and improving the strength and toughness of the gel foam.

[0039] The cross-linking agent is aluminum citrate, and its mass percentage in the fire extinguishing agent is 0.1 to 1%;

[0040] The aluminum ions (Al3+) in the cross-linking agent aluminum citrate can undergo coordination reactions with functional groups with lone pair electrons, such as hydroxyl and carboxyl groups, on the molecular chains of konjac flour and xanthan gum, forming cross-linking points between different molecular chains. These cross-linking points connect the molecular chains of konjac flour and xanthan gum together, transforming the originally relatively loose physical network structure into a tighter and more stable three-dimensional cross-linked network structure, greatly improving the mechanical properties, thermal stability and deformation resistance of the gel, and effectively preventing the collapse and rupture of the gel foam during use.

[0041] The flame retardant is dimethyl methylphosphonate, and its mass percentage in the fire extinguishing agent is 3 to 5%;

[0042] Dimethyl methylphosphonate can increase the viscosity and elasticity of the foam liquid film and slow down the drainage rate. The polar groups on the molecular chains in the foam liquid film interact with the polar groups of dimethyl methylphosphonate, which can further improve the stability of the foam. At the same time, the phosphoric acid and metaphosphoric acid produced by the decomposition of dimethyl methylphosphonate when exposed to high temperature can promote the formation of a carbon layer. The free radical scavenger produced by its decomposition inhibits the free radical chain reaction of the combustion reaction to reduce the combustion rate. After the colloid in the foam liquid film is carbonized by heat, it interweaves with the carbon layer promoted by dimethyl methylphosphonate, thereby enhancing the flame retardant properties of the coal body.

[0043] The performance and effect of the fluorine-free gel foam of the present invention are further verified by the following examples, comparative examples and test examples;

[0044] Example 1:

[0045] This embodiment discloses a fluorine-free gel foam fire extinguishing agent, which is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentages of the components are: composite foaming agent 0.8%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0046] The composite foaming agent used is prepared from sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside in a mass ratio of 1:1:0.6; the composite gelling agent is prepared from konjac flour and xanthan gum in a mass ratio of 4:1; the cross-linking agent is aluminum citrate; and the flame retardant is dimethyl methylphosphonate.

[0047] At the same time, this embodiment also discloses a method for preparing the above-mentioned fluorine-free gel foam fire extinguishing agent, comprising the following steps:

[0048] The first step is to prepare a foam component;

[0049] S1: Weigh 6 g of dimethyl methylphosphonate using an electronic balance and pour it into a beaker containing 92.4 g of water. Stir evenly and dissolve it fully in water.

[0050] S2: Weigh 0.6 g of sodium lauryl sulfate, 0.6 g of sodium dodecylbenzenesulfonate, and 0.4 g of decyl glucoside using an electronic balance, and then pour them into the aqueous solution containing dimethyl methylphosphonate, stir evenly, and completely dissolve them to obtain a foam component;

[0051] The second step is to prepare the gel component;

[0052] S1: Weigh 0.5g of aluminum citrate using an electronic balance and pour it into a beaker containing 97.5g of water. Stir well and dissolve it fully in water.

[0053] S2: Weigh 1.6 g of konjac flour and 0.4 g of xanthan gum using an electronic balance, pour the konjac flour and xanthan gum into an aqueous solution containing aluminum citrate while stirring, and stir until completely dissolved to obtain a gel component;

[0054] The third step is to mix the foam component and the gel component;

[0055] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a fluorine-free gel foam composition.

[0056] Example 2:

[0057] This embodiment discloses a fluorine-free gel foam fire extinguishing agent, which is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentages of the components are: composite foaming agent 1.6%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0058] The composite foaming agent used is prepared from sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside in a mass ratio of 1:1:0.6; the composite gelling agent is prepared from konjac flour and xanthan gum in a mass ratio of 4:1; the cross-linking agent is aluminum citrate; and the flame retardant is dimethyl methylphosphonate.

[0059] At the same time, this embodiment also discloses a method for preparing the above-mentioned fluorine-free gel foam fire extinguishing agent, comprising the following steps:

[0060] The first step is to prepare a foam component;

[0061] S1: Weigh 6 g of dimethyl methylphosphonate using an electronic balance and pour it into a beaker containing 90.8 g of water. Stir evenly and dissolve it in water.

[0062] S2: 1.2 g of sodium lauryl sulfate, 1.2 g of sodium dodecylbenzenesulfonate, and 0.8 g of decyl glucoside were weighed using an electronic balance, and then poured into the aqueous solution containing dimethyl methylphosphonate, stirred evenly, and completely dissolved to obtain a foam component;

[0063] The second step is to prepare the gel component;

[0064] S1: Weigh 0.5g of aluminum citrate using an electronic balance and pour it into a beaker containing 97.5g of water. Stir well and dissolve it fully in water.

[0065] S2: Weigh 1.6 g of konjac flour and 0.4 g of xanthan gum using an electronic balance, pour the konjac flour and xanthan gum into an aqueous solution containing aluminum citrate while stirring, and stir until completely dissolved to obtain a gel component;

[0066] The third step is to mix the foam component and the gel component;

[0067] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a fluorine-free gel foam composition.

[0068] Example 3:

[0069] This embodiment discloses a fluorine-free gel foam fire extinguishing agent, which is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentages of each component are: composite foaming agent 0.8%, composite gelling agent 0.5%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0070] The composite foaming agent used is prepared from sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside in a mass ratio of 1:1:0.6; the composite gelling agent is prepared from konjac flour and xanthan gum in a mass ratio of 4:1; the cross-linking agent is aluminum citrate; and the flame retardant is dimethyl methylphosphonate.

[0071] At the same time, this embodiment also discloses a method for preparing the above-mentioned fluorine-free gel foam fire extinguishing agent, comprising the following steps:

[0072] The first step is to prepare the foam component

[0073] S1: Weigh 6 g of dimethyl methylphosphonate and pour it into a beaker containing 92.4 g of water. Stir evenly and fully dissolve it in water.

[0074] S2: Use an electronic balance to weigh 0.6 g, 0.6 g, and 0.4 g of sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate (LAS-30), and decyl glucoside (APG0814), respectively, and then pour them into the aqueous solution containing dimethyl methylphosphonate in the first step, stir evenly, and dissolve them completely.

[0075] Step 2: Prepare the gel component

[0076] S1: Weigh 0.5g of aluminum citrate and pour it into a beaker containing 98.5g of water. Stir well and fully dissolve it in water.

[0077] S2: Weigh 0.8g of konjac flour and 0.2g of xanthan gum using an electronic balance, pour them into the aqueous solution containing the cross-linking agent in the first step while stirring, and stir evenly to completely dissolve them.

[0078] Step 3: Mix the foam component and the gel component

[0079] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a gel foam composition.

[0080] Example 4:

[0081] This embodiment discloses a fluorine-free gel foam fire extinguishing agent, which is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentages of the components are: composite foaming agent 1.6%, composite gelling agent 0.8%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0082] The composite foaming agent used is prepared from sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside in a mass ratio of 1:1:0.6; the composite gelling agent is prepared from konjac flour and xanthan gum in a mass ratio of 4:1; the cross-linking agent is aluminum citrate; and the flame retardant is dimethyl methylphosphonate.

[0083] At the same time, this embodiment also discloses a method for preparing the above-mentioned fluorine-free gel foam fire extinguishing agent, comprising the following steps:

[0084] The first step is to prepare a foam component;

[0085] S1: Weigh 6 g of dimethyl methylphosphonate using an electronic balance and pour it into a beaker containing 90.8 g of water. Stir evenly and dissolve it in water.

[0086] S2: 1.2 g of sodium lauryl sulfate, 1.2 g of sodium dodecylbenzenesulfonate, and 0.8 g of decyl glucoside were weighed using an electronic balance, and then poured into the aqueous solution containing dimethyl methylphosphonate, stirred evenly, and completely dissolved to obtain a foam component;

[0087] The second step is to prepare the gel component;

[0088] S1: Weigh 0.5g of aluminum citrate using an electronic balance and pour it into a beaker containing 97.9g of water. Stir well and dissolve it fully in water.

[0089] S2: Weigh 1.28 g of konjac flour and 0.32 g of xanthan gum using an electronic balance. Pour the konjac flour and xanthan gum into an aqueous solution containing aluminum citrate while stirring, and stir until completely dissolved to obtain a gel component.

[0090] The third step is to mix the foam component and the gel component;

[0091] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a fluorine-free gel foam composition.

[0092] Comparative Example 1:

[0093] Comparative Example 1: A foam fire extinguishing agent is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentage of each component is: composite foaming agent 1.2%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0094] The composite foaming agent used is prepared from sodium lauryl sulfate and sodium fatty alcohol polyoxyethylene ether sulfate, with a mass ratio of 1:1; the composite gelling agent is prepared from konjac flour and xanthan gum, with a mass ratio of 4:1; the cross-linking agent is aluminum citrate; and the flame retardant is dimethyl methylphosphonate.

[0095] The steps for preparing a gel foam fire extinguishing agent provided in Comparative Example 1 are as follows:

[0096] The first step is to prepare a foam component;

[0097] S1: Weigh 6 g of dimethyl methylphosphonate using an electronic balance and pour it into a beaker containing 92.4 g of water. Stir evenly and dissolve it fully in water.

[0098] S2: Weigh 1.2 g of sodium lauryl sulfate and 1.2 g of sodium fatty alcohol polyoxyethylene ether sulfate using an electronic balance, then pour them into the aqueous solution containing dimethyl methylphosphonate, stir evenly, and completely dissolve them to obtain a foam component;

[0099] The second step is to prepare the gel component;

[0100] S1: Weigh 0.5g of aluminum citrate using an electronic balance and pour it into a beaker containing 96.7g of water. Stir well and dissolve thoroughly in water.

[0101] S2: Weigh 1.6 g of konjac flour and 0.4 g of xanthan gum using an electronic balance, pour the konjac flour and xanthan gum into an aqueous solution containing aluminum citrate while stirring, and stir until completely dissolved to obtain a gel component;

[0102] The third step is to mix the foam component and the gel component;

[0103] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a fluorine-free gel foam composition.

[0104] Comparative Example 2:

[0105] Comparative Example 2: A foam fire extinguishing agent is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentage of each component is: composite foaming agent 1.2%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0106] The composite foaming agent used is prepared from sodium lauryl sulfate and sodium fatty alcohol polyoxyethylene ether sulfate, with a mass ratio of 1:1; the composite gelling agent is prepared from sodium silicate and xanthan gum, with a mass ratio of 3:2; the cross-linking agent is aluminum citrate; and the flame retardant is dimethyl methylphosphonate.

[0107] The steps for preparing a gel foam fire extinguishing agent provided in Comparative Example 2 are as follows:

[0108] The first step is to prepare the foam component

[0109] S1: Weigh 6 g of dimethyl methylphosphonate and pour it into a beaker containing 91.6 g of water. Stir evenly and fully dissolve it in water.

[0110] S2: Use an electronic balance to weigh 1.2 g of sodium lauryl sulfate and 1.2 g of sodium fatty alcohol polyoxyethylene ether sulfate, and then pour them into the aqueous solution containing dimethyl methylphosphonate in the first step, stir evenly, and dissolve them completely.

[0111] Step 2: Prepare the gel component

[0112] S1: Weigh 0.5g of aluminum citrate and pour it into a beaker containing 97.5g of water. Stir well and dissolve it fully in water.

[0113] S2: Use an electronic balance to weigh 1.2g of sodium silicate and 0.8g of xanthan gum respectively. Pour the sodium silicate and xanthan gum into the aqueous solution containing aluminum citrate in the first step while stirring, and stir evenly to completely dissolve them.

[0114] Step 3: Mix the foam component and the gel component

[0115] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a gel foam composition.

[0116] Comparative Example 3:

[0117] Comparative Example 3: A foam fire extinguishing agent is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentage of each component is: composite foaming agent 1%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

[0118] The composite foaming agent used is prepared from decyl glucoside and sodium polyoxyethylene fatty alcohol ether sulfate, with a mass ratio of 1:1; the composite gelling agent is prepared from sodium alginate and xanthan gum, with a mass ratio of 2:3; the cross-linking agent is calcium chloride; and the flame retardant is dimethyl methylphosphonate.

[0119] The steps for preparing a gel foam fire extinguishing agent provided in Comparative Example 3 are as follows:

[0120] The first step is to prepare the foam component

[0121] S1: Weigh 6 g of dimethyl methylphosphonate and pour it into a beaker containing 92 g of water, stir evenly, and fully dissolve it in water.

[0122] S2: Use an electronic balance to weigh 1.4 g of sodium fatty alcohol polyoxyethylene ether sulfate and 0.6 g of decyl glucoside, and then pour them into the aqueous solution containing dimethyl methylphosphonate in the first step, stir evenly, and completely dissolve them.

[0123] Step 2: Prepare the gel component

[0124] S1: Weigh 0.5g of calcium chloride and pour it into a beaker containing 97.5g of water. Stir well and dissolve it fully in water.

[0125] S2: Use an electronic balance to weigh 0.8g of sodium alginate and 1.2g of xanthan gum respectively, and pour them into the aqueous solution containing calcium chloride in the first step while stirring, and stir evenly to make them completely dissolved.

[0126] Step 3: Mix the foam component and the gel component

[0127] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a gel foam composition.

[0128] Comparative Example 4:

[0129] Comparative Example 4: A foam fire extinguishing agent is composed of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the mass percentage of each component is: composite foaming agent 0.8%, composite gelling agent 1%, cross-linking agent 1%, and the balance is water.

[0130] The composite foaming agent used is prepared from sodium dodecyl sulfate and sodium dodecylbenzene sulfonate in a mass ratio of 1:1; the composite gelling agent is prepared from sodium carboxymethyl cellulose and sodium silicate in a mass ratio of 3:2; and the cross-linking agent is aluminum citrate.

[0131] The steps for preparing a gel foam fire extinguishing agent provided in Comparative Example 4 are as follows:

[0132] The first step is to prepare a foam component;

[0133] Weigh 0.8 g of sodium dodecyl sulfate and 0.8 g of sodium dodecylbenzenesulfonate using an electronic balance, pour them into a beaker containing 98.4 g of water, stir them evenly, and dissolve them completely to obtain a foam component;

[0134] The second step is to prepare the gel component;

[0135] S1: Weigh 2g of aluminum citrate using an electronic balance and pour it into a beaker containing 96g of water. Stir evenly and dissolve it fully in water.

[0136] S2: Weigh 1.2 g of sodium carboxymethyl cellulose and 0.8 g of sodium silicate using an electronic balance, pour them into the aqueous solution containing aluminum citrate while stirring, and stir until they are completely dissolved to obtain a gel component;

[0137] The third step is to mix the foam component and the gel component;

[0138] The foam component is completely poured into the gel component, stirred evenly, and after fully mixing, poured into a foaming device for foaming to obtain a gel foam composition.

[0139] Test Example 1

[0140] The gel foam compositions prepared in Examples 1-4 and Comparative Examples 1-4 were tested for apparent viscosity, foaming multiple and water retention.

[0141] 1. Viscosity measurement: Use an NDJ-5S rotational viscometer to measure viscosity. Select an appropriate rotor speed for viscosity measurement. Place the prepared gel foam composition into a beaker. When the rotor is completely immersed in the foam, begin viscosity measurement. When the reading on the viscosity counter screen stabilizes, record the reading at this time as the viscosity of the foam.

[0142] 2. Determination of foaming multiple: Pour the uniformly mixed gel foam composition into the foaming device, set the air compressor pressure to 6MPa for foaming, take 500ml of the obtained foam into a beaker, weigh the foam (m), and calculate the foaming multiple according to the following formula:

[0143] E = 500 / m;

[0144] 3. Foam stability measurement: 100 ml of the prepared gel foam composition was placed in a beaker, and its natural storage time at room temperature was observed.

[0145] 4. Water retention: Place 100 ml of the foam composition in a crucible and record the total mass of the crucible and foam, M0. Then, place the crucible containing the foam in a 60°C constant temperature drying oven for 8 hours. Record the weight of the crucible, M1, and calculate the water retention according to the following formula:

[0146] Φ=(M0-M1) / M0;

[0147] The test data results are shown in Table 1.

[0148] Table 1

[0149] Apparent viscosity Foaming multiple Foam stability Water loss rate Example 1 13915mPa·s 7.7 ≥48h 18.4％ Example 2 15638 mPa·s 9.3 ≥72h 12.5％ Example 3 7440 mPa·s 15.0 ≥18h 54.6％ Example 4 9673mPa·s 11.7 ≥22h 35.7％ Comparative Example 1 12675mPa·s 6.8 ≥36h 27.6％ Comparative Example 2 8654mPa·s 14.8 ≥15h 61.2％ Comparative Example 3 9749 mPa·s 12.4 ≥21h 37.3％ Comparative Example 4 6893 mPa·s 20.0 ≥5h 89.8％

[0150] As shown in Table 1, although the foaming ratios of Examples 1-4 are lower than those of Comparative Examples 1-4, their foam viscosities and natural storage times at room temperature are significantly longer than those of Comparative Examples 1-4. This indicates that the foam stability of Examples 1-4 is significantly better than that of Comparative Examples 1-4, suggesting that the three-dimensional network structure formed by cross-linking xanthan gum, konjac gum, and aluminum citrate helps improve the stability and water retention of the foam.

[0151] Test Example 2

[0152] The gel foam compositions prepared in Examples 1-4 and Comparative Example 1 / 4 were subjected to a burning resistance test. The gel foam compositions were burned at a high temperature of 1300°C for 2 minutes. The carbonization of the gel foam exposed to the fire was measured. The test results are as follows: Figure 1 As shown. Figure 1 Comparing the graphs a to d of the changes in Examples 1-4 after burning for 2 minutes with the graph e of the changes in Comparative Example 1 after burning for 2 minutes, it can be seen that the burning resistance of the foam is significantly improved with the increase of the concentration of the gelling agent. Figure 1 By comparing the change graph c of Example 3 after burning for 2 minutes with the change graph f of Comparative Example 4 after burning for 2 minutes, it can be seen that the different components of the gelling system have a significant effect on the burning resistance of the foam, indicating that xanthan gum and konjac gum have a good synergistic effect with aluminum citrate, which can significantly improve the thermal stability of the foam.

[0153] Test Example 3

[0154] The microscopic morphology of the coal sample covered with the gel foam composition prepared in Example 2 is as follows: Figure 2 Observation Figure 2 The results show that after gel foam treatment, the surface of the coal sample exhibits a continuous and evenly distributed gel film, which seals the pores and cracks in the coal and isolates the air from contact. The gel foam has a stable structure and is not easily decomposed or inactivated by external environmental factors such as temperature and humidity. It maintains its protective effect on the coal over a long period of time, effectively reducing the likelihood of oxidation reactions and providing a strong safeguard against coal spontaneous combustion.

[0155] Test Example 4

[0156] The stage division and corresponding characteristic temperature of the coal sample after the raw coal and gel foam composition were treated for 336 hours (14 days) with oxygen are shown in Table 2. The experimental data were obtained by Netzsch STA449 comprehensive thermal analyzer. The TG-DTG curve of the coal sample after the raw coal and gel foam were treated for 336 hours is shown in Figure 3 、 Figure 4As shown in Table 2, the characteristic temperatures of the coal samples treated with gel foam were significantly higher than those of the original coal. For example, T2 increased from 153°C to 195°C, T5 was delayed from 411°C to 441°C, and T7 was delayed from 598°C to 635°C, representing increases of 42°C, 30°C, and 37°C, respectively. This indicates that the gel foam treatment slowed the oxidation process of the coal and effectively inhibited its spontaneous combustion.

[0157] Table 2

[0158]

[0159]

[0160] In Table 2, T1 represents the dehydration temperature, which means the temperature at which the first minimum value appears on the differential thermogravimetric (DTG) curve. This is the temperature at which the first minimum value on the DTG curve is caused by the evaporation of water in the coal and the beginning of desorption of some gases.

[0161] T2 represents the drying cracking temperature, which means: it appears as the first minimum value on the thermogravimetric (TG) curve. At this time, the coal sample reaches the lowest mass due to water evaporation, and then the activity of coal molecules increases and oxidation weight gain begins.

[0162] T3 represents the temperature of maximum weight gain rate, which means: it is generally determined according to the DTG curve, and is the temperature of the first maximum point of the DTG curve; this point is the sign that the oxygen absorption rate of the coal sample reaches its peak, reflecting the intensity of the reaction between the coal sample and oxygen, which corresponds to the maximum weight gain rate point of the coal sample in the oxygen absorption reaction.

[0163] T4 represents the pyrolysis temperature, which means: generally according to the TG curve, it is the temperature point on the TG at which the coal body weight reaches the maximum. This is because the coal sample reaches the maximum mass due to the oxidation reaction, and then the coal structure begins to decompose, and is about to enter a faster weight loss stage.

[0164] T5 represents the ignition point temperature, which means: draw tangents to the TG curve through T4 and T6 respectively, and the temperature corresponding to the intersection is the ignition point temperature. After this point, the coal sample enters the combustion stage, which is the turning point for the coal sample to switch from slow oxidation to intense combustion.

[0165] T6 represents the maximum weight loss rate temperature, which means: the temperature corresponding to the maximum weight loss rate peak on the DTG curve. As the coal-oxygen reaction reaches its climax, a large amount of CO, CO2 and other gases are released, causing the coal sample quality to drop sharply.

[0166] T7 represents the burnout temperature, which means that this temperature point indicates that the combustible components in the coal sample are completely consumed, the residual mass tends to be stable, and no longer fluctuates significantly with temperature changes.

[0167] The present invention has the following beneficial effects:

[0168] 1. The sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside components of the composite foaming agent and the konjac flour and xanthan gum components of the composite gelling agent of the present invention do not contain any fluorine components, are easily degraded, and meet environmental protection requirements;

[0169] 2. The konjac flour and xanthan gum in the present invention are cross-linked with aluminum citrate to form a stable three-dimensional cross-linked network structure, which greatly improves the mechanical properties, thermal stability and deformation resistance of the gel foam, effectively increases the resistance to the flow of the foam solution, and slows down the drainage rate and coarsening rate of the foam, improves the stability and water retention capacity of the foam, has good synergy, and enhances the fire extinguishing effect.

[0170] 3. The gelled foam of the present invention can maintain its structural integrity and will not collapse when facing a high-temperature fire source of more than 1300°C. At the same time, it will not burn itself and will not provide combustion-supporting conditions for the combustion of the flame, thereby having an excellent inhibitory effect on the spontaneous combustion of coal.

Claims

1. A fluorine-free gel foam fire extinguishing agent, characterized in that: The fluorine-free gel foam fire extinguishing agent consists of a composite foaming agent, a composite gelling agent, a cross-linking agent, a flame retardant and water; the weight percentage of each component is: composite foaming agent 0.1-3%, composite gelling agent 0.1-5%, cross-linking agent 0.1-1%, flame retardant 3-5%, and the balance is water.

2. The fluorine-free gel foam fire extinguishing agent according to claim 1, characterized in that: The weight percentages of the components in the fluorine-free gel foam fire extinguishing agent are: composite foaming agent 1.8%, composite gelling agent 1%, cross-linking agent 0.25%, flame retardant 3%, and the balance is water.

3. The fluorine-free gel foam fire extinguishing agent according to claim 2, characterized in that: The composite foaming agent is prepared by compounding two or three of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and decyl glucoside; the mass ratio of the sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and decyl glucoside is 1:0.8 to 1:0.6 to 0.

8.

4. The fluorine-free gel foam fire extinguishing agent according to claim 3, characterized in that: The composite gelling agent is prepared from konjac flour and xanthan gum; the mass ratio of the konjac flour to the xanthan gum is 3-4:

1.

5. The fluorine-free gel foam fire extinguishing agent according to claim 4, characterized in that: The cross-linking agent is aluminum citrate.

6. The fluorine-free gel foam fire extinguishing agent according to claim 5, characterized in that: The flame retardant is dimethyl methylphosphonate.

7. A method for preparing the fluorine-free gel foam fire extinguishing agent as claimed in claim 6, characterized in that: The following steps are involved: S1, preparing a foam component; S2, preparing gel components; S3. Mix the foam component and the gel component and stir them evenly, pour them into a foaming device for foaming to obtain a fluorine-free gel foam fire extinguishing agent.

8. The method for preparing the fluorine-free gel foam fire extinguishing agent according to claim 7, wherein: The step S1 comprises the following steps: S11. Weigh dimethyl methylphosphonate in proportion, add it to a beaker filled with water, stir evenly and allow the dimethyl methylphosphonate to completely dissolve; S12. Weigh sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and decyl glucoside in proportion, pour them into a beaker containing dimethyl methylphosphonate in sequence, and stir evenly to obtain a foam component.

9. The method for preparing the fluorine-free gel foam fire extinguishing agent according to claim 8, wherein: The step S2 comprises the following steps: S21. Weigh aluminum citrate in proportion, add it to a beaker filled with water, and stir evenly; S22. Weigh konjac flour and xanthan gum in proportion, slowly add them to the beaker containing aluminum citrate while stirring during the addition process to obtain a gel component.

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