Forest and grassland fire extinguishing barrier foam and preparation method thereof

Abstract

The application discloses a forest and grassland fire extinguishing and blocking foam and a preparation method thereof. The foam is prepared by a foam generating system and is composed of 5-20% of A material, 0.5-0.8% of B material, 1.8-3% of a coagulant and the rest of water. The A material is composed of 1-10 parts of organic aggregate and 100-200 parts of inorganic aggregate. The B material is composed of 2-7 parts of a composite surfactant and 1-6 parts of a cross-linking agent. The coagulant is carbon dioxide gas. The inorganic aggregate is condensed to form colloidal particles and polymerized under the action of hydrogen ions generated by the dissolution of carbon dioxide to form a three-dimensional network structure of the gel skeleton, the foam is changed into the gel foam, and a heat-insulating and fire-resistant blocking layer is formed on the surface of the combustible material. The foam prepared by the application has controllable gel time, high fire extinguishing efficiency, good heat-insulating effect and environmental friendliness, and has a wide application prospect in forest and grassland fire.

Description

Technical Field

[0001] This invention belongs to the field of fire-fighting foam extinguishing technology. Specifically, this invention relates to a fire-blocking foam for extinguishing forest and grassland fires and its preparation method. Background Technology

[0002] The response to and management of forest and grassland fires has always been a thorny challenge facing the international community. Regarding the prevention and control of forest and grassland fires, scholars both domestically and internationally have conducted in-depth research on fire spread mechanisms, fire extinguishing materials, and firefighting equipment, achieving a series of preliminary results. However, the global development of forest and grassland fire extinguishing technologies and equipment has currently encountered a bottleneck, particularly in improving the extinguishing efficiency of fire extinguishing agents, where enormous potential remains to be explored.

[0003] Gel foam, as an innovative fire extinguishing technology, is currently used to extinguish Class A and Class B fires. It is mainly composed of foaming agents, gelling agents, accelerators, and functional additives. This foam can quickly cover a large area, effectively isolating oxygen and heat, thus achieving rapid fire extinguishing. It also possesses excellent adhesion and penetration, reaching deep into combustible materials to effectively prevent reignition, making it highly effective for extinguishing Class A fires. Simultaneously, it can rapidly construct firebreaks, demonstrating exceptional application value in forest and grassland fire fighting scenarios. Its fire resistance is significantly improved compared to traditional foam extinguishing agents, thus making it also highly suitable for Class B fires.

[0004] Currently, gel foams are mainly composed of organic and inorganic components. Inorganic gel foams are used on a large scale, primarily in the coal mining sector. Further technological improvements and optimizations are needed to expand their application in other fields. Existing materials for forest fire prevention, such as WO2024 / 103869A1, CN119034151A, and CN118543065A, provide excellent ideas, but some unresolved issues remain.

[0005] 1. Regarding the selection of gelling agents, inorganic materials produce gel foams with lower cost, better heat resistance, and faster preparation, but they also have problems such as high concentration, poor water retention, brittleness, and easy powdering; organic materials have better film-forming properties and require lower addition amounts, but they also have problems such as high cost, high viscosity, and poor foaming effect.

[0006] 2. Most of the acidic coagulants used are corrosive and irritating, which can affect instruments and personnel. If the acidity of the coagulant is too high, it can also cause local pH to be too high during mixing, resulting in clumping and interfering with the foaming process.

[0007] 3. Poor compatibility between preparation methods and gel materials; poor foaming effect of high-viscosity mixtures; small adjustment range of traditional accelerator dosage; difficulty in achieving precise control of curing time in conventional systems; mismatch between gelling time and usage conditions will cause problems such as unstable foaming effect and equipment blockage.

[0008] 4. Some materials have shortcomings in terms of environmental protection. If they are used in forest and grassland fire fighting, they may cause significant ecological problems.

[0009] 5. The preparation and formulation process is too cumbersome and complicated, which is not conducive to industrial production and rapid fire response.

[0010] In view of the above challenges and problems, there is an urgent need to develop an environmentally friendly gel foam that is specifically designed for forest and grassland fires and has both efficient firefighting and rapid isolation effects. Summary of the Invention

[0011] The primary objective of this invention is to provide a fire-resistant foam for forest and grassland fires. This novel gel foam formulation should possess excellent foam performance, stable low-temperature performance, low cost, and outstanding environmental properties, thereby effectively addressing various forest and grassland fire scenarios.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A forest and grassland fire extinguishing barrier foam is made of the following components by weight percentage: 5% to 20% of component A, 0.5% to 0.8% of component B, 1.8% to 3% of accelerator, and the remainder is water;

[0014] Material A is made by mixing 100-200 parts of inorganic aggregate and 1-10 parts of organic aggregate;

[0015] Material B is prepared by mixing 2 to 7 parts of a composite surfactant and 1 to 6 parts of a crosslinking agent;

[0016] The accelerator is the acidic gas carbon dioxide.

[0017] Preferably, the inorganic aggregate is one of liquid sodium silicate, liquid lithium silicate, and liquid potassium silicate. The concentration and modulus of the inorganic aggregate affect the cost, gel time, and gel strength. Inorganic aggregates with a modulus of 3 or higher are selected, as they are more effective at low concentrations. The proportion of the inorganic aggregate in component A is adjusted according to actual needs. Liquid sodium silicate with a modulus of 3.3 and a Baume degree of 42° is preferred.

[0018] Preferably, the organic aggregate is one or more long-chain organic polymer materials, such as sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyacrylamide, xanthan gum, silicone polyether emulsion, and sodium alginate. The addition of organic aggregate improves the water retention and strength of the foam, but excessive addition will result in high viscosity and cost, affecting the foaming ratio; therefore, it should constitute a relatively low proportion in component A.

[0019] Preferably, the composite surfactant is formulated from anionic surfactant and amphoteric surfactant in a mass ratio of 1-6:1-6. Different mass ratios result in different foaming effects; the optimal overall foaming effect is achieved when the mass ratio is 4:1.

[0020] Furthermore, the anionic surfactant is a sulfonic acid surfactant, preferably sodium dodecyl sulfonate or sodium α-olefin sulfonate; the amphoteric surfactant is a quaternary ammonium base surfactant, preferably cocamidopropyl betaine, lauramide propyl betaine, or cocoyl hydroxysulfonate. Both types of surfactants have high solubility and good environmental friendliness.

[0021] Preferably, the crosslinking agent is one or more substances containing organic functional groups and silaneoxy groups, such as γ-aminopropyltriethoxysilane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane.

[0022] Furthermore, the pressure and flow rate of compressed carbon dioxide can be used to control the foaming ratio.

[0023] The second objective of this invention is to provide a method for preparing the above-mentioned forest and grassland fire extinguishing barrier foam. A targeted generation system is designed, the preparation steps are simple, the foaming and gelation processes are easy to control, and the foam can be prepared rapidly.

[0024] Step 1: Set up a foam generation system. The system includes a water source, an A / B mixture storage tank, a proportioning pump, a carbon dioxide gas source, a gas flow control valve, and a foaming device. The water source and the A / B mixture storage tank are connected to the liquid inlet of the foaming device through the proportioning pump, and the carbon dioxide gas source is connected to the gas inlet of the foaming device through the gas flow control valve.

[0025] Step 2: Mix material A and material B according to the formula ratio and add the mixture to the storage tank for later use; the system uses a proportioning mixing pump to mix water with the mixture of materials A and B to obtain a diluted solution with a set ratio and outlet pressure, which is then introduced into the foaming device.

[0026] Step 3: Carbon dioxide, the coagulant, is introduced into the foaming device through a gas flow control valve to control the outlet pressure and flow rate, and partially dissolved to play a coagulant role; the outlet of the foaming device is the fire-extinguishing foam for forest and grassland fires.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention combines the advantages of both organic and inorganic materials through doping and cross-linking reinforcement to create a gel foam. While ensuring the foam's fire extinguishing effect, it reduces the concentration of inorganic aggregates, lowers material costs, and avoids clogging caused by excessively rapid gelation. Organic aggregates can bind to water molecules through hydrogen bonds into the three-dimensional network structure, enhancing the foam skeleton's ability to retain moisture and improving foam stability. The cross-linking agent strengthens the connection between inorganic and organic aggregates, further stabilizing the foam skeleton and improving the adhesion between the foam and combustible materials.

[0029] 2. This invention screens out a sulfonic acid-based anionic surfactant and a quaternary ammonium base zwitterionic surfactant, and optimizes their compounding to obtain an environmentally friendly composite surfactant with excellent foaming performance.

[0030] 3. In this invention, no precipitation will occur prematurely when carbon dioxide of any concentration or in excess is added. This is because the dissolution process of carbon dioxide and the appropriate acidity prevent the local pH value from becoming too high during the gelation process.

[0031] 4. Using carbon dioxide provides an inert atmosphere, isolating oxygen and suffocating the fire source. Furthermore, its hydrolysis products can interrupt the chain reaction of combustion, participating in the fire extinguishing mechanism and further enhancing the fire extinguishing effect of the foam. Moreover, utilizing industrial waste gases such as power plant flue gas as a carbon dioxide source, it participates in the gel reaction to form the gel skeleton of the foam, creating a heat-insulating and fire-resistant barrier layer on the surface of combustible materials, thus achieving greenhouse gas fixation and reducing direct carbon dioxide emissions.

[0032] 5. Both materials A and B are liquids, allowing for rapid on-site mixing. A specially designed foam generation system enables the rapid production of gel foam with a high expansion ratio and fine texture. The relationship between foaming time, gel time, and separation time is achieved through formulation adaptation: foaming time < gel time < separation time. A shorter foaming time than gel time avoids excessive mechanical disturbance after gelation, which could damage the gel foam framework. A shorter gel time than separation time allows the foam to gel and solidify during a relatively fine stage before coarsening. This preparation method is simple, fast, and produces high-quality, fine foam.

[0033] 6. The foam prepared by this invention can maintain fluidity for a certain period of time, fully cover and impregnate combustibles, and play the functions of fire extinguishing and cooling. The gelation time is controllable, the fire extinguishing efficiency is high, the heat insulation effect is good, and it is environmentally friendly. It has broad application prospects in forest and grassland fires. Attached Figure Description

[0034] Figure 1This is a schematic diagram of the preparation system for fire-extinguishing barrier foam designed for forest and grassland fires according to the present invention. In the diagram, 1-water source; 2-AB material mixture storage tank; 3-proportioning mixing pump; 4-carbon dioxide gas source; 5-gas flow control valve; 6-foaming device. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] Unless otherwise specified, all percentages and parts mentioned in this implementation plan are by weight.

[0037] First, numerous embodiments were carried out, in which different inorganic aggregates, different organic aggregates, different coagulants, and different crosslinking agents were used to prepare this fire-extinguishing barrier foam under laboratory conditions. The materials with better gelation effect, fire extinguishing effect, and barrier effect were screened out, and the theoretical principle was analyzed. The invention content has been introduced and will not be listed here.

[0038] In the following embodiments, material A is prepared by thoroughly stirring 120 parts of inorganic aggregate and 3 parts of organic aggregate in a reactor for 1 to 3 hours to fully dissolve and mix them; the inorganic aggregate is liquid sodium silicate (i.e., water glass) with a modulus of 3.3 and a Baume degree of 42°, and the organic aggregate is hydroxypropyl methylcellulose and sodium alginate in a mass ratio of 1:1.

[0039] Material B is prepared by mixing 6 parts of a composite surfactant and 1 part of a crosslinking agent in a reactor for 0.1 to 1 hour. The composite surfactant is prepared by mixing sodium α-olefin sulfonate, an anionic surfactant and cocamidopropyl betaine, in a mass ratio of 4:1, in a reactor for 0.1 to 1 hour. The crosslinking agent is 3-(2-aminoethyl)-aminopropyltrimethoxysilane.

[0040] Figure 1 This is a schematic diagram of the preparation system for fire-extinguishing barrier foam designed for forest and grassland fires according to the present invention. The system includes a water source 1, an AB mixture storage tank 2, a proportioning pump 3, a carbon dioxide gas source 4, a gas flow control valve 5, and a foaming device 6. The water source 1 and the AB mixture storage tank 2 are respectively connected to the liquid inlet of the foaming device 6 through the proportioning pump 3, and the carbon dioxide gas source 4 is connected to the gas inlet of the foaming device 6 through the gas flow control valve 5.

[0041] The specific implementation method is as follows: First, a suitable formula ratio is selected through comprehensive analysis; according to the ratio, material A and material B are mixed into a liquid and added to the AB mixture storage tank 2 for later use; the system uses a proportional mixing pump 3 to mix the water provided by water source 1 with the AB mixture to obtain a diluted liquid with a set ratio and outlet pressure, which is then introduced into the foaming device 6; compressed carbon dioxide provided by carbon dioxide gas source 4 is controlled by a gas flow control valve 5 to regulate the outlet pressure and flow rate, and is then introduced into the foaming device 6 for foaming, where partial dissolution plays a role in promoting coagulation; the outlet of the foaming device 6 produces forest and grassland fire extinguishing barrier foam.

[0042] Example 1

[0043] A forest and grassland fire extinguishing barrier foam is made by introducing carbon dioxide at 1 MPa with a volume of 12 times the liquid volume (at normal temperature and pressure, hereinafter omitted) in a foaming device, comprising the following liquid components by mass percentage: 5% of component A, 0.5% of component B, and the balance being water.

[0044] Example 2

[0045] A forest and grassland fire extinguishing barrier foam is made by introducing carbon dioxide at 1 MPa at a mass percentage of 12 times the volume of the liquid into a foaming device, comprising the following liquid components in mass percentage: 10% component A, 0.5% component B, and the balance being water.

[0046] Example 3

[0047] A forest and grassland fire extinguishing barrier foam is made from the following liquid components by mass percentage: 15% component A, 0.5% component B, and the balance being water. The foam is produced by introducing carbon dioxide at 1 MPa at a volume 12 times that of the liquid in a foaming device.

[0048] Example 4

[0049] A forest and grassland fire extinguishing barrier foam is made from the following liquid components by mass percentage: 20% component A, 0.5% component B, and the balance being water, by introducing 1 / 2 volume of carbon dioxide at 1 MPa into a foaming device.

[0050] A forest and grassland fire extinguishing barrier foam, comprising the following mass percentages: Example 5

[0051] The liquid composition is: 10% of component A, 0.6% of component B, and the remainder is water. It is prepared by passing carbon dioxide at 1 MPa through a foamer at a volume 12 times that of the liquid.

[0052] Example 6

[0053] A forest and grassland fire extinguishing barrier foam is made from the following liquid components by mass percentage: 10% component A, 0.7% component B, and the balance being water. The foam is produced by introducing carbon dioxide at 1 MPa in a foaming device at a volume 12 times that of the liquid.

[0054] Example 7

[0055] A forest and grassland fire extinguishing barrier foam is made from the following liquid components by mass percentage: 10% component A, 0.8% component B, and the balance being water. The foam is produced by introducing carbon dioxide at 1 MPa at a volume 12 times that of the liquid in a foaming device.

[0056] Example 8

[0057] A forest and grassland fire extinguishing barrier foam is made from the following liquid components by mass percentage: 10% component A, 0.7% component B, and the balance being water. Carbon dioxide is introduced into the foamer at 1 MPa at a volume 16 times that of the liquid.

[0058] Example 9

[0059] A forest and grassland fire extinguishing barrier foam is made by introducing carbon dioxide at 1 MPa at a volume of 20 times the volume of the liquid in a foaming device, comprising the following mass percentages of liquid: 10% of component A, 0.7% of component B, and the balance being water.

[0060] Nine groups of fire-extinguishing barrier foams for different forest and grassland fires were prepared. The gelation time, foaming ratio (foam volume / raw material liquid volume), foam effect (whether there was liquid separation before gelation, whether the foam decayed), and fire resistance (deformation within 15s of ignition burn was poor, deformation within 30s was average, and no deformation within 30s was good) were measured from the time of spraying. The data obtained are shown in Table 1.

[0061] Table 1. Case studies of foam extinguishing techniques for different forest and grassland fires

[0062]

[0063]

[0064] Examples 1 to 4, based on different amounts of component A and accelerator, show that the prepared foams all successfully gelled without flowing when inverted, exhibiting strong adhesion to wood. However, excessively high concentrations of component A may result in excessively low foam moisture content, affecting foam quality and fire resistance. Insufficient accelerator additions may cause excessively long foam gelation time, with liquid separation occurring before gelation. Therefore, a concentration range of 10% to 15% of component A is preferred.

[0065] Examples 2, 5, 6, and 7, with different amounts of B material added, show that when the amount of B material added exceeds 0.7%, the foaming ratio and foam quality no longer increase, and the fire resistance remains largely unchanged.

[0066] Examples 6, 8, and 9 with different gas-liquid ratios show that the gas-liquid ratio mainly affects the foaming ratio, but excessively high foaming ratios with low foam density can also affect the fire resistance effect.

[0067] In one of the superior embodiments, the foam does not exhibit liquid separation or decay, and after burning for 30 seconds, a hard shell forms on the foam surface without overall collapse, demonstrating good burn resistance.

[0068] While the above embodiments provide some implementation methods of the present invention, for those skilled in the art, any changes or modifications to the component ratios or substitutions of similar materials in the embodiments without departing from the basic principles of the present invention are all within the scope of the claims to which this invention pertains.

Claims

1. A fire-blocking foam for extinguishing forest and grassland fires, characterized in that, It is made from the following components by weight percentage: 10% to 15% of component A, 0.5% to 0.7% of component B, 1.8% to 3% of coagulant, and the remainder is water; Material A is made by mixing 100-200 parts of inorganic aggregate and 1-10 parts of organic aggregate; the inorganic aggregate is one of liquid sodium silicate, liquid lithium silicate, and liquid potassium silicate, and the organic aggregate is one or more of long-chain organic polymer materials. Material B is prepared by mixing 2 to 7 parts of a composite surfactant and 1 to 6 parts of a crosslinking agent; the composite surfactant is prepared by compounding anionic surfactant and amphoteric surfactant in a mass ratio of 1 to 6: 1 to 6, wherein the anionic surfactant is a sulfonic acid surfactant, the amphoteric surfactant is a quaternary ammonium base surfactant, and the crosslinking agent is one or more substances containing organic functional groups and silane groups. The accelerator is acidic gas carbon dioxide; The foam is prepared through the following steps: Step 1: Construct a foam generation system. The system includes a water source (1), an AB material mixture storage tank (2), a proportioning pump (3), a carbon dioxide gas source (4), a gas flow control valve (5), and a foaming device (6). The water source (1) and the AB material mixture storage tank (2) are respectively connected to the liquid inlet of the foaming device (6) through the proportioning pump (3). The carbon dioxide gas source (4) is connected to the gas inlet of the foaming device (6) through the gas flow control valve (5). Step 2: Mix material A and material B according to the formula ratio and add them to the storage tank for later use; the system uses a proportional mixing pump (3) to mix water and the mixture of material A and B to obtain a diluted liquid with a set ratio and outlet pressure, which is then introduced into the foaming device (6). Step 3: Carbon dioxide, the coagulant, is controlled by the gas flow control valve (5) to control the outlet pressure and flow rate, and is introduced into the foaming device (6) to foam and partially dissolve to play a coagulant role; the outlet of the foaming device (6) produces forest and grassland fire extinguishing barrier foam.

2. The forest and grassland fire extinguishing foam according to claim 1, characterized in that, The organic aggregate is one or more of the following: sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyacrylamide, xanthan gum, silicone polyether emulsion, and sodium alginate.

3. The forest and grassland fire extinguishing foam according to claim 1, characterized in that, The anionic surfactant is one of sodium dodecyl sulfonate and sodium α-olefin sulfonate; the amphoteric surfactant is one of cocamidopropyl betaine, lauramide propyl betaine, and cocamidopropyl hydroxysulfonate.

4. The forest and grassland fire extinguishing foam according to claim 1, characterized in that, The crosslinking agent is one or more of γ-aminopropyltriethoxysilane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane.

Images