RU2730075C1 - Fire extinguishing compound - Google Patents

Abstract

FIELD: fire extinguishing compounds.

SUBSTANCE: invention relates to fire-extinguishing compositions containing or forming a gas phase, which can be used in extinguishing landscape fires. Technical result is achieved by using composition for fire extinguishing, including carbamide, sodium bicarbonate and water, which additionally contains phosphorus-boron-containing oligomer and carboxymethyl cellulose at following ratio of components, wt%: carboxymethyl cellulose 1; phosphorus-boron-containing oligomer 7–8; carbamide 5–10; sodium bicarbonate 6–8; water – balance.

EFFECT: invention widens range of means for fire extinguishing and reduces time of fire extinguishing.

1 cl, 2 tbl

Description

The invention relates to fire extinguishing compositions containing or forming a gas phase, which can be used in extinguishing landscape fires.

Known fire extinguishing composition [ed. wit. SU912177, A62D1 / 00, publ. 15.03.82], which includes water, an inert component, mainly nitrogen, and carbon dioxide is used as an auxiliary component in the form of a catalyst.

The disadvantage of this invention is the limited scope of its application, i.e. its use to extinguish the fire of certain substances or operation in the absence of people due to the high toxicity of the introduced components.

Known foaming composition for extinguishing fires, including a surfactant (surfactant) - alkyl sulfonates, foam stabilizer - higher fatty alcohols and / or derivatives of amines, butanol, butyl ether of acetic acid, urea (carbamide), corrosion inhibitor - polyphosphate, simple water-soluble ethers cellulose, which can be used carboxymethyl cellulose or methyl cellulose and water [patent 2158155, A62D1 / 00, publ. 27.10.00].

The disadvantage of this invention is the presence in the compositions of substances that emit highly toxic combustion products during operation.

The closest to the proposed chemical composition is a foaming agent for extinguishing fires [ed. wit. 2203707, A62D1 / 04 publ. 10.05.03.] Containing normal primary ammonium alkyl sulfates of C12-C14 fractions, butanol, carbamide, and sodium bicarbonate.

The disadvantage of this composition is the use of substances that, when burned, release toxic products.

The objective of the present invention is to obtain a water-polymer fire-extinguishing solution with high flame retardant properties.

The technical result of the claimed invention is to expand the arsenal of means for extinguishing a fire and reducing the time to extinguish a fire.

The technical result is achieved by using a composition for extinguishing fires, including carbamide, sodium bicarbonate and water, which additionally contains a phosphorus-boron-containing oligomer and carboxymethyl cellulose, with the following ratio of components, wt%:

Carboxymethyl cellulose 1 Phosphorus-boron oligomer 7-8 Urea 5-10 Bicarbonate of soda 6-8 Water Rest

The presence of sodium bicarbonate and urea in the extinguishing solution helps to expand the temperature range of the solution in the environment. The content of the phosphorusboron-containing oligomer in the formulation, as a flame retardant additive, contributes to the localization and elimination of fires. The amide form of nitrogen in carbamide is well absorbed by plants damaged by landscape fire.

In the proposed fire extinguishing composition, the following components are used: carboxymethyl cellulose (GOST 11293-89), phosphorus-boron-containing oligomer, carbamide (GOST 2081-2010), sodium bicarbonate (GOST 2156-76), drinking water (GOST R 51232-98).

The Mooney viscosity of the claimed composition was determined using a VZ-246 viscometer (d = 0.4 cm) by the time the liquid flowed out of the capillary, which was determined using an electronic stopwatch with an accuracy of ± 0.01 s. The temperature of the investigated working solutions of fire-extinguishing compositions is 20 ° C.

The flowability of the tested samples of fire-extinguishing compositions from various surfaces is determined as follows:

2 ml of the composition was applied to a wooden block measuring 20 × 6 cm, fixed on a tripod horizontally. The bar was gradually tilted until the composition drained from the wooden surface. Measurements of the runoff angle were carried out in 3-fold repetition.

The measurement of the angle of runoff on a hydrophobic surface (plastic) was carried out in a similar manner.

The spreading of fire-extinguishing solutions on horizontal surfaces was determined by the method:

On a hydrophobic plastic surface, 2 ml of working extinguishing solutions were applied. The spreading area of these samples, which formed an ellipse, is measured using measuring instruments and is determined by the formula:

S = πRr,

where R is the semi-major axis of the ellipse, r is the semi-minor axis of the ellipse, π ≈ 3.14

Determination of the spreading area of samples of fire extinguishing compositions on a hydrophobic surface is carried out in the initial period of time and 15 minutes after the application of the working composition to the hydrophobic surface.

The fire extinguishing properties of the test solutions along vertical surfaces were determined by the following method:

The wooden sample was fixed vertically in a tripod using clamps. The sample was heated using a Multiplaz 3500 plasma torch with a flame temperature of 8000 ° C.

The sample was placed at a distance of 5 cm from the Multiplaz 3500 plasma torch. The torch flame was directed to the sample and the time of the start of the test was recorded.

Investigations into the combustion of southern reed in natural conditions were determined by the following method:

A model experiment was set up to simulate a natural steppe fire. Dry stems of southern reed, in windy weather, were set on fire from different sides of the selected fire source with a size of 25 ... 50 cm. At the moment of the highest intensity of burning of the reed, it was extinguished with the investigated water-polymer composition at a distance of 30 ... 45 cm. In order to study the possibility of repeated fire, the reed was ignited again after 30 ... 40 minutes.

The fire extinguishing mechanism of the proposed agent is incorporated in the developed formulation consisting of a water-soluble polymer of carboxymethylcellulose, a phosphorus-containing additive in the form of a phosphorus-boron-containing oligomer, carbamide, sodium bicarbonate. The fire extinguishing effect of the combined composition is represented by a complex of chemical interactions that occur during the cessation of combustion, namely:

- TSF (Phosphorus-boron-containing oligomer) - is a viscous uncolored liquid, readily soluble in water, dimethylformamide, acetone, alcohols - an oligomer obtained from boric acid and dimethylphosphite. Contains flame retardant additives that help localize and eliminate fires.

- Urea (carbamide), which is part of the fire extinguishing composition, in the form of an aqueous solution, under the influence of the temperature of the flame or radiant heat exchange, decomposes into two components: carbon dioxide (CO ₂ ) and ammonia (NH ₃ ). The chemical reaction proceeds with significant heat absorption, therefore the effect of cooling the combustion reaction zone occurs.

- Ammonia is a colorless gas with a characteristic odor (the smell of "ammonia") - it burns well with the release of nitrogen. Nitrogen (N ₂ ) is an inert diluent of the combustion reaction zone and an effective extinguishing agent. Ammonia, passing into a liquid state, and subsequently evaporating under the influence of the heat of the flame, absorbs a large amount of heat. In this case, the temperature in the combustion zone decreases and, as a consequence, the flame goes out.

- Sodium bicarbonate (NaHCO ₃ ) is used to neutralize the acids formed in the reaction.

The compositions of the proposed extinguishing solution and the prototype are presented in table 1.

Table 1

Ingredients, wt. % Content of mixture components Prototype Example 1 Example 2 Example 3 Carboxymethyl cellulose 1 1 1 0 Phosphorus-boron oligomer 7 7.5 8 0 Urea five 7.5 ten five Bicarbonate of soda 6 7 8 0.05 Water 81 77 73 75.95 Normal primary ammonium alkyl sulfates of C12-C14 fractions 0 0 0 12 Butanol 0 0 0 7

Table 2 shows the comparative technical and operational characteristics of the proposed extinguishing solution and the prototype.

table 2

Index Test result Example 1 Example 2 Example 3 Prototype Appearance homogeneous liquid without stratification homogeneous liquid without stratification homogeneous liquid without stratification homogeneous liquid without stratification Mass fraction of sediment without thermal exposure and after thermal exposure,% five 4 five 0 Density at 20 ° С, kg / m ³ 1070 ± 5 1078 ± 5 1081 ± 5 1020 ± 5 Hydrogen index of 1% aqueous solution, pH 6.7 ± 0.2 6.8 ± 0.2 6.8 ± 0.2 8.7 ± 0.1 Kinematic viscosity at 20 ° С, mm ² s, no more 2.15 ± 0.10 2.16 ± 0.10 2.17 ± 0.10 2.57 ± 0.03 Biodegradability Soft (decay over 94%) Soft (decay over 94%) Soft (decay over 94%) Soft (decay over 90%) Duration of extinguishing a model hearth with a diameter, cm
25
28
50 91
115
145 90
113
142 86
109
135 102
276
not extinguished Mooney viscosity, conv. units
- specific viscosity
- relative viscosity
- reduced viscosity 2.02
3.02
2.02 2.17
3.17
2.17 2.23
3.23
2.23 Solution drainage angle, °
- from a wooden surface
- from a hydrophobic surface (plastic) 7.9
7.2 8.5
6.4 9.0
6,7 Solution spreading area, cm ²
- after application to the surface
- in 15 minutes 5.94
7.07 6.36
7.42 8.48
9.33 Fire-extinguishing properties of the test solutions on vertical surfaces
- change in the mass of a wooden sample, g
- the volume of the burnt surface, cm ³
- time of resistance to combustion, s
- group of fire retardant efficiency 4.639
17,494
23
I 4.639
17,494
23
I 3.826
15,079
31
I Investigations of the combustion process of southern reed in natural conditions
- time of extinguishing at dispersive wetting, s
- re-ignition of the processed southern reed
- visual observation of the combustion process 11 ... 13
Not visible
Flames are small and steep. Charring. Slight white smoke. Instant 10 ... 13
Not visible
Flame tongues are precipitous. Slight white smoke. Charring along the edges of southern reed stems. 8 ... 11
Not visible
The flame is hardly noticeable. Slight smoke production. Instant.

The claimed liquid-phase extinguishing composition is characterized by a neutral environment and biodegradability, which contributes to the rapid recovery of the landscape biocenosis after a fire.

Examples 1-3. Preparation of fire-extinguishing compositions (in accordance with the recipe given in table 1).

1. A solution was prepared (A) - a weighed portion of carboxymethyl cellulose was placed in glass flasks and poured with cold water. The resulting mixture in a water bath (temperature 40 ... 50 ° C) was dissolved with stirring until homogeneous. A phosphorus-boron-containing oligomer and carbamide were added to the resulting solutions.

2. Prepare solution (B) - Sodium bicarbonate was dissolved in a small amount of water with stirring.

3. The solution (A) was gradually added to the solution (B) with stirring, the resulting solutions were brought with water to obtain a predetermined mass of the target product.

For the preparation of solutions, water with a hardness not exceeding 3.0 mg-eq / l (soft water) is used.

Environmental conditions during the experiments: air and water temperature 20 ± 2 ° C, pressure 84-106.7 kPa, relative air humidity 60-70%.

Thus, a composition for extinguishing fires, including carbamide, carboxymethyl cellulose, sodium bicarbonate, a phosphorus-boron-containing oligomer and water, with the stated ratio of components, provides a reduction in the time for extinguishing a fire.

Claims (2)

Composition for extinguishing fires, including carbamide, sodium bicarbonate and water, characterized in that the composition additionally contains a phosphorus-boron-containing oligomer and carboxymethyl cellulose in the following ratio of components, wt%: Carboxymethyl cellulose 1 Phosphorus-boron oligomer 7-8 Urea 5-10 Bicarbonate of soda 6-8 Water Rest