DE1921871C3 - Foam extinguishing method and suitable means - Google Patents

Description

(CH ₃ J ₃ SiO-

CH ₃

—S — R ^a N (R ^? JR' — SiO_

Si (CH ₃ )

3U

contains, in which π 1 to 3, M an ammonium group or an alkali metal, R ¹ a divalent hydroxy-substituted alkylene, cycloalkylcn, alkyleneoxyalkylene or cycloalkyleneoxyalkylene group with 3 to 18 carbon atoms, R ² a divalent hydrocarbon group with 2 to 10 carbon atoms and R ³ a Hydrogen or a monovalent hydrocarbon group having 1 to 8 carbon atoms and the hydroxyl substituent of the group R ¹ is bonded to a carbon atom which is adjacent to that bonded to nitrogen.

") Process according to claim 1, characterized in that the organosilicon compound is one of the formula

(CH ₃ J ₃ SiO- [NaO ₃ SC ₂ H ₄ N (CH ₃ ) -CH ₂ CH (OH) CH ₂ OC ₃ H ₆ Si (CH ₃ ) O] - Si (CH ₃ I ₃

used.

3. The method according to claim 1, characterized in that one is used as the organosilicon compound those of the formula

(CH ₃ J ₃ SiO- [NaO ₃ SC ₂ H ₄ N (CH ₃ ) -CH ₂ CH (OH) CH ₂ OC ₃ H ,, Si (CH ₃ ) O] j ^ Si (CH ₃ k

35

used.

4. The method according to any one of claims I to 3, characterized in that the organosilicon compound used in an amount of from about 0.01 to about 0.4 weight percent based on the total weight of the liquid.

5. The method according to any one of claims 1 to 4, characterized in that as additional Foaming agent uses a partially hydrolyzed protein.

6. A method according to any one of claims I to 5, characterized in that f to the surface of the burning liquid hydrocarbons toils First, a dry chemical Feucrlösch-

45 medium and then the aqueous liquid is applied.

7. The method according to any one of claims I to 6, characterized in that there is an aqueous Liquid containing about 0.03 to 5 percent by weight of a water-soluble polymer based on the weight of the liquid.

8. The method according to claim 7, characterized in that the water-soluble polymer Polyoxyethylene glycol or carboxymethyl cellulose is used.

9. Agents containing the organosilicon compound of the general formula

(CH ₃ J ₃ SiO-

CH ₃ MO ₃ SR ² N (R ³ ) R'-SiO

, Si (CH ₃ I ₃

Wherein π I to 3, M an ammonium group or an alkali metal, R 'a divalent hydroxysubitituiertc alkylene, cycloalkylene, alkyleneoxyalkylene or cycloalkyleneoxyalkyl group with 3 to 18 carbon atoms, R ² a divalent hydrocarbon group with 2 to 10 carbon atoms and R ³ a hydrogen atom or a cin-

55 denotes a valent hydrocarbon group having 1 to 8 carbon atoms and the hydroxyl substituent of the group R ¹ is bonded to a carbon atom which is adjacent to that bonded to nitrogen, for carrying out the process according to claim 1.

The invention relates to a foam extinguishing process for nnendc liquid hydrocarbons or for Vcr- ; in the ignition of flammable cabbage waterffc by applying a foam from a liquid which is a surface-active organosilicon compound, optionally together with an additional foaming agent.

Extinguishing hydrocarbons with low flash points, especially fuels and oiling, through foam cover is known. The cover closes off volatile, flammable fumes the ambient air and prevents re-ignition. The water flowing out of the foam serves to cool the source of the fire.

I 921 871

Many foam fire extinguishers are mechanical Foam, thus obtained by mechanical Aufichüumen with air. Other foams are produced by the chemical reaction of an alkali carbonate with a acidic compound, such as aluminum sulfate, with release formed by carbon dioxide, if necessary a foam stabilizer is used, such as liquorice, Saponin, glue, glycerin, glucose, sodium sulfate, Quillaya bark.

Purely mechanical foams are suitable with hydrolyzed animal or vegetable proteins in water several additives, such as buffers, agents for lowering the freezing point, Foam stabilizers, bactericides and anti-corrosion agents.

A mechanical foam of hydrolyzed protein, while quite cheap, has several disadvantages. So a heavy cover with foam is needed; the hydrocarbon easily re-ignites, when the foam cover z. B. is torn by wind.

In addition, protein foams are not contractual with dry chemical extinguishers.

The applicability of dry chemical extinguishers for Hydrocarbon fire is limited because it does not cool the source of the fire and suppress it allow flammable vapors.

However, it is desirable to have a lock-out device to be used together with a foam. However, it becomes a highly potent organosilicon compound With a dry extinguishing agent and a protein foam applied, the foam airs together very quickly.

The use of hydrocarbons together with hydrolyzed proteins ^; Nening offers advantages in improving compatibility with organosilicon compound-treated potassium bicarbonate, but heavy, non-tearable covers are still required. Finally found mechanical foams with the help of surface-active agents made of perfluorocarbon compounds together with high molecular weight synthetic polymers (USA. Patent

3 258 423) application.

Certain organosilicon compounds have been

Already used in Mittein for extinguishing and / or preventing hydrocarbon fires. The addition a nonionic liquid polyalkyl silicon compound into a stabilized chemical foam Sodium bicarbonate and aluminum sulfate (U.S. Pat. No. 2,790,502) increases the flash point and Focus.

Hydrolyzable anionic silicone esters or mixtures have already been used in preventive fire protection condensed ethyl silicates obtained by reacting carbon tetrachloride with an aikanoi, applied, (British Patent 5 * 548).

However, these nonionic alkyl silicon compounds do not form any vapor-blocking layers, but in some cases act as defoamers

2s and so extinguish the fire.

The invention now relates to a foam extinguishing method for burning liquid hydrocarbons or to prevent the ignition of flammable hydrocarbons using a foam a foamable aqueous liquid containing a surface-active organic silicon compound, optionally together with additional foams, the inventively applied Organosilicon compound of the general formula

(CH ₃ ) MO ₃ SR ² N (R ³ IR ¹ -SiO

"SifCH ₃ ) ₃

corresponds to where η 1 to 3, M is an ammonium group or an alkali metal, R ^{1 is} a divalent hydroxy-substituted alkylene, cycloalkylene. Alkyleneoxyalkylene or cycloalkyleneoxyalkylene group with 3 to 18 carbon atoms, R ^{2 is} a divalent hydrocarbon group with 2 to IO carbon atoms and R ^{3 is} a hydrogen atom or monovalent hydrocarbon group with 1 to 8 carbon atoms and the hydroxyl substituent of the group R ¹ is bonded to a carbon atom that is attached to the is adjacent bound to nitrogen.

According to the invention, preferred organosilicon compounds are those of the average formula

(CHj) ₃ SiO- [NaO ₃ SC ₂ H ₄ N (CH ₃₎ -CH ₂ CH (OH) CH ₂ OC ₃ H ₆ Si (CH ₃₎ O] - Si (CH _{3) 3}

applied. It is appropriate that the concentration of organosilicon compound etsva 0.01 to 0.4 percent by weight, based on the liquid. As an additional foaming agent in the inventive Means a partially hydrolyzed protein are used. The application of the foam can be done in two ways, either by placing the foamed liquid on the source of the fire applies above or introduces the foam below the burning surface, so that it is attached to the Rising surface can extinguish the fire. It is also possible to focus on the source of the fire first Usual dry fire extinguishing agent and then only apply foam according to the invention. One The aqueous liquid used according to the invention is further improved by a content of fiw: i 0.03 to 5 percent by weight of a water-soluble Polymer, in particular polyoxyalkylene glycol or carboxymethyl cellulose.

A major advantage of the method according to the invention is that it causes renewed inflammation Freshly extinguished sources of fire are prevented. For this reason, the method according to the invention is suitable especially for combating hydrocarbons (Gasoline, naphtha, toluene, benzene]

and other highly flammable vapors. Due to the simultaneous cooling effect of the draining liquid The foam can also be used to successfully fight fires on the basis of kerosene and diesel oils or jet fuels. The liquids according to the invention are also distinguished turned to organosilicon compounds due to their considerable thermal stability. You can do these substances add known foam systems or he

in accordance with the fire extinguishing method with known , other systems, such as dry extinguishing, combine

Drain off the foams too

yg ^

'S drainage of the FIO *** ... aqueous show- "J""j ^ n ^ SS Wn d ^^, containing the surface- s ^" J ¹ ^ _{isl cine} continuous supply

the, i, ^

torn foam cover.

SSSÄ
Foaming agents do not show any

We-

^ 3 g

velvet viscosity and di

Formers are used and the organosilicon compounds used according to the invention are only used in relatively low concentrations, e.g. B. elwa iO.l /., Is higher concentrations _6n low Molekulargew.ch s _isatkonzc ntrat.onen m of nus

he ^ gem, received,

Powders such as a suppression of the vapors applied by the "Sndungsgemaß Organosü-cumver _{rfindunB can dic sch} a _U m, ldenden _{with ODC} ^ _OHNC Zusaü: before, cm" nnoder

Benefits even when in very small amounts be used. Most surprisingly, st de Ability of small amounts of the design applied organosilicon compounds hydrolyzed Protei foam systems with dry l · -euer

to make extinguishing chemicals compatible.

The concentration of the organosulfur compounds used according to the invention is within narrow limits not critical. However, it is desirable, at least about

0 01% of the organosilicon compound, based on the total weight of the liquid phase of the foam to use. When the organosilicon compound is used as the main foam stabilizer is, the liquid phase preferably contains about 0 4 up to about 10%, in particular about 0.5 to 1%: is however the main shaft stabilizer is a common one Substance, e.g. B. hydrolyzed protein, are less as needed about 0.4% up to 0.01%.

The spreading film that seals off the vapors is created by the drainage of liquid from the Sheep lamellas formed. The speed of the Drainage is therefore important. With the known Foam systems based on hydrolyzed

Protein _S is m drainage undesirable since it causes the Wassergeha't and the strength of the foam be,

"VtSSS ^ iSL the Ge

da Sctau «^ u _ammcn ^^
Jr ^ renzna _Flussigke it spreads s.ch as

such as "W" _coals wasserstofToberfla _C hc under J ^ _{and acts ah} barrier against vaporization

v _{Mo li (f nkeit is} the injection of the

the surface and is suitable bcson- ^ ^. ^ _LöschmiUe) over d, c

beUanKD ^ _{Uchen FüllstulzC} n stirred in

Jank ^^ J foam _it reaches the surface, the Jj durcS the foam and the, effect of the _{UNU, rdrücku} the Dampfabgabc ng similar ^{r un} _{b muster} n on the surface. J _{can be in} concentration.

S n _Dilute with Wrsser dievcrschaunv _{ibt. There can} also be a non- _{canceling YJ for the Miud to} delay the "

It contains fluids, such as isopropanol (about 1 bu AbgeBera enw, ^ ^ _Gcsamtgewlch

X in order to reduce the viscosity and a polymer against oxidative degradation. _{It also} means ^Y _{k ann} to Erniedrigum _{and a} ntibakterielle center and contain at _Customized re purposes. Since ₈₀ percent by weight

Brains

rams the concentrate

R ^J

M 0, SR ² NR ¹ SiO

where »1 I. in particular

CH ₃ CH ₃

J 1

MO ₃ SR ² NCH ₂ CH (OH) CH ₂ OC ₃ H ₆ SiO—

CH ₃ CH ₃

MO ₃ SR ² NC ₆ H ₃ (OH) C ₂ H ₄ SiO-

in which R ^{2 is} an alkylene or phenylene radical.
The groups

R ³

—R ² NR'—

(U)

(IV)

The pH value used according to the invention Liquid should be between 7 and 10 and can be adjusted with buffer if necessary.

The ratio of the foam volume to the weight of the liquid in the foam is called "foam expansion" Are defined. The foam expansion is adjusted via the volume of air used for foaming and is generally between about 4 and 11. The Foam expansion is also important in controlling the rate of liquid drainage and flowability of the foam.

Foams with less expansion can be thin and watery and are usually not sufficient heat resistant. Too much expansion foams have high viscosities and are inadequate flowable. By introducing more air, the expansion of a foam increases and the flow rate decreases. The molecular weight, the type and the concentration of the polymer which retards the drainage also affects the drainage rates.

Instead of air, other gases such as nitrogen can also be used for foaming. Carbon dioxide, difluorodichloromethane use.

The organosilicon compounds used according to the invention have only a very limited solubility in liquid hydrocarbons. You can z. B. by changing the type of to the organosilicon Backbone bound hydrophilic group influence, and / or it can thereby the solubility be lowered that the ratio of hydrophilic to hydrophobic parts in the organosilicon compound is increased. The lower the solubility in the hydrocarbon. the longer the effective Lifespan of the film that closes the vapors, provided the surfactant still has surface tension can lower.

Preferred siloxy units of the organosilicon compounds of the formula I used according to the invention are:

it in the formula

Alkyl OH -R ² NCH -CR ⁵ -R ⁴ R ⁴ -

is indicated in which R ⁴ = R ³ or together with the carbon atoms bonded to it form cycloalkyl groups with up to 12 carbon atoms, R ^{5 is} an alkylene group, an oxyalkylene group - OR ² - or an alkyleneoxyalkylene group -R ² OR ² -, e.g. B. with alkyl amino groups and hydroxyl groups substituted alkyleneoxyalkylene groups, such as

CH ₃ OH

- C ₂ H ₄ NCH ₂ CHCH ₂ OC ₃ H ₆ -

CH ₃ OH

-C ₂ H ₄ NCH ₂ CHOCH ₂ CH ₂ -C ₂ H ₅ OH

- C ₃ H ₆ NCHjCHCH ₂ OCH ₂ CH ₂ CH ₂ correspondingly substituted cycloalkylene groups. how

OH

CH ₂ CH ₂ CH ₂ -

C ₂ H ₅

OH

(ΙΠ) so substituted alkylene groups C ₄ H ₉ OH

- C ₂ H ₄ NCH ₂ CCH ₂ CH ₂ -

CH ₃ CH ₃ OH

- C ₂ H ₄ NCH ₂ CHCH ₂ CH ₂ -

and appropriately substituted cycloalkyleneoxyalkylene groups:

Me C ₂ H ₄ N

OH CH ₂ OCH ₂ CH ₂ CH ₂ -

.H,

should consist of 5 to 20 carbon atoms, where

the hydroxyl group and the amino nitrogen atom. The invention is illustrated by the following examples

are bonded to adjacent carbon atoms, as explained in more detail.

ei ^ CS>! c "^ *« **. „„ ,.. » an aqueous _solution

(CH _{3) 3} SiO- [NaO ₃ SC ₂ H ₄ N (CH ₃₎ -CH ₂ CH (OH) CH ₂ OC ₃ H ₆ Si (CH ₃₎ O] -Si (CH,) ₃

a film blocking off the vapors on the upper surface of the gasoline. The gasoline apparently ran out gradually exposed by draining the foam and breaking up the foam during the previous one 4 minutes. As the burning area slowly increased, the flames overcame the surface area, that made them look like candles at first uie time to completely overcome the effect of the film (burn-back line) was 0.2 minutes. This showed the formation and mode of action of the film blocking the vapors during the fire extinguishing. As shown, the effect of the Film does not depend on the foam's barrier effect on the

ok

15th

mi *, a concentration of 0.77 percent by weight Solids and a polymer of polyethylene oxide, the 1% aqueous solution of which has a viscosity of 3OcP at 25 ° C, in a concentration of 0.54 percent by weight.

A pan of 18.5 dm ² was filled with a layer of water to a height of 7.6 cm and 3.81 motor gasoline for test purposes was poured onto the water layer. The gasoline was ignited and after a pre-burning time of 10 to 15 seconds an air-expanded foam was applied to the surface of the burning hydrocarbon which had been produced from an aqueous solution of 1.13 percent by weight of the organosiloxane used according to Example I. An application rate of 41 cm ³ / dm ² · min with a foam expansion of 8.9 was used to produce a flowable foam. The fire was extinguished in 0.42 minutes, and the amount required to extinguish the fire, that is, the application density, was 36.7 cnrVdm ² . The flame from a propane burner was applied over the foam surface at the interface between the hot metal wall and the foam to determine how long the foam served as an effective barrier to the flammable vapors. The obtained value was measured as the time from fire resistance to reignition. The value in this case was 22.1 minutes. When the re-ignition sat down, the time required was measured. until the flames completely destroyed the coating of foam and film and let the gasoline burn free. This value was defined as the burn-back time. In this case, the re-ignited gasoline burned as a candle-like flame, although the entire surface no longer had foam. This indicated the presence

Example 2

In this example, the compatibility is shown a foam of the Example I used organo NLH £ tr ^{8 Matching Caps} "with ordinary silicon tern aI ^a i t ^{IU mb! Carbonate and} siliconbehandeltem Ammoniumd.hydrogenphosphat

wenduT Η ⁰ "y ^erS u ^{UCh according to} WeI» ntcr Vcr-NachTmi "i ^leiCh , ^Cn foam solution repeated. Feupplf K T " ^{dCS FeUerS the usual} up kS 7 ^{P aU} u ^{the show} " if1 area were scattered, where the ^{breakage of the foam} took place. The T ^{5 Pr} ° P ^{a "burning} ers was then wicdcr- '" ^gerichtct · ^w orauf the Schaumschich.

s ^{long became ki}

Example 3

According to the extinguishing method according to Example I, a foam was made from an aqueous solution of an organosilicon mixture the average formula

with a solids concentration of 0.75 "0 and the polyethylene oxide polymer of Example 1 with a solids concentration of 0.6% was used. The fire was extinguished in 0.8 minutes. A foam expansion of 8.8 and an application density 5c of 32.4 cm ³ / dm ² were used, the time from fire resistance to reignition was 17.5 minutes and the burn-back time was 0.3 minutes.

Example 4

The benefits of injecting foams in accordance with the invention below the surface are as follows Example explained.

The foam used in Example 3 was used. The foam was injected in the middle of the bottom of the tank and rose through the water layer and through the gasoline layer to the burning surface. The fire extinguishing was carried out in 0.47 minutes with an expansion value of 1.8 and an application density of 19.3 cm ³ dm ² . 65 The time between fire resistance and re-ignition is 15.4 minutes. The comparison of this value with the corresponding value according to example 3

rNaOjSC ₂ H ₄ N (CH, »CH ₂ CH (OH, CH ₂ OC _J H _t , Si, CH ,, O _{] l} , S" CH ,,,

a, erin ^{Cr A} _A ^nwcndu "g ^d" Tauchlöschverfah- and d, ^{"S? e} ™ ^to r ^ndu B aui" gsdiehte is required as it b ^ ^a ^ ^{short 's} time is wiped out of the A, ^applicati niögicnlt "the surface direct

Comparative experiment

55 with a

60 KSLTiP ^ ¹ * PV ^ignorance ^ gl, chkeit one

ken-Ϊ ^ ^hydrOl * ^{ized Proteln} S ^^ extinguishing agent. This foam

i ^again * inflammation after an

The test gasoline added. ^{And after} a pre-Lf H ou ^ the ^{surface of} the burning coal was expanded ^{with air ! ^ 0ht} · ^The ^^ "Tnlamellen constant ^an , the ^usual Mrolysierte Proteiny, ⁰¹ ^ ?; ⁰² ^ ^{1 in W} ^ er. The order ^{qII 0111} ^ ¹ ^ ^{dncr Schaumexpandie} -5,9, wöbe, emiquid foam produces wu.de.

12th

The fire was extinguished in one minute, 17 seconds, and the amount of water required for extinguishing or the application density was 51 cm ³ / dm ² . A propane burner flame was passed across the foam surface along the hot metal wall to determine how long the foam served as an effective barrier to the flammable vapors. This time from fire resistance to reignition was 58 seconds. When the fire started again, the time in which the flames had completely destroyed the foam coating and had allowed the gasoline to burn freely (burn-back time) was 6.75 minutes.

The experiment was repeated and after the fire was extinguished, a few grams of silicone treated potassium bicarbonate and silicone treated ammonium dihydrogen phosphate over the Scattered foam surface. The foam treated with the potassium bicarbonate immediately shrank and was destroyed. The foam treated with the phosphate slowly formed holes at the Fulverstelle. A flame held in the foam cover ignited the gasoline.

Example 5

The effects of a surfactant organosiloxane on the same hydrolyzed protein system according to comparison is explained in more detail in this example.

The foam solution consisted of 3 percent by volume hydrolyzed protein at 0.075 percent by weight an amphoteric organosilicon compound of the formula

_(CH3 J ₃ SiO [NaOjSC ₂ H ₄ N (CH ₃₎ CH ₂ CH (OH) CH ₂ OC ₃ H ₆ Si (CH ₃₎ O] ₁₄ Si (CH

air was used to generate foam. The foam expansion was 12.9. to achieve a liquid foam. The fire was extinguished in 58 seconds. The application density was 39 cm ³ dm ² . The time from extinction to re-ignition was 10 minutes and 18 seconds compared to 58 seconds in the comparison test without the use of an organosilicon compound according to the invention. After about 9 minutes all of the foam had disappeared and what appeared to be free gasoline remained. However, no ignition could be achieved for another 1.5 minutes. The effect of the film serving as a vapor barrier was visible for a further 3.5 minutes. The burn-back time was 41 seconds. The fire was again extinguished with the foam and a few grams of conventional fire extinguishing powder from the comparison test was sprinkled on the foam. No foam degradation was observed. The dry chemicals remained on the foam surface without changing its appearance. Stirring with the flame of a propane burner did not ignite the gasoline.

Example 6

The comparative experiment was carried out using an air-expanded foam made from an aqueous solution of 0.02 percent by weight of the amphoteric organosilicon compound from Example 5 and a 3 percent by volume solution of the same hydrolyzed protein. The fire was extinguished in 65 seconds using a foam expansion of 8.4. An application density of 3) 3

43 cm ³ / cm ² was required to obtain extinction. The time from fire resistance to re-ignition was 5 minutes and 17 seconds and the burn-back time was 37 seconds.

By adding the above usual powders to the foam, holes were obtained in the foam where the Chemicals had fallen, but the foam did not completely collapse. The effects a barrier film for the vapors were observed, ever but not to the same extent as in Example 5.

The results of Examples 5, 6 and the comparative experiment are summarized in the following table represents

comparison

common fire extinguishing powder

Example 5

common fire extinguishing powder

I- MD ₁₅ M **)

Example 6

common fire extinguishing powder
+ MD ₁₅ M **)

Weight
percent

3.48

3.48
0.075
3.48
0.02

cm ³ /
dm ² min

expansion

5.9

12.9

8.4

Delete line

(Minutes:

Seconds)

0:58

: 05

cnv '/ dm

example

Time to Wicderent / ündunj
(Minutes: seconds

Burn back time
(Minutes: seconds)

Compatibility with KHCO,

Dampfspc rr (remodeling

comparison
5

0 58
10:18

5:17

no
Yes

Yes*)

neiti

yes, about 3.5 minutes: effective

Yes*)

*) Not as far as in example 5.

13 ° 14

Example 7

This example illustrates the superiority of high molecular weight polymers as retardants for drainage against low molecular weight polymers.

A foam solution was prepared containing 0.1% hydroxyethyl cellulose with a viscosity of 40 cP in 1% aqueous solution at 25 ° C and 0.85 percent by weight of an amphoteric surface-active agent formula

(CH ₃₎ JSiO- [NaO ₃ SC ₂ H ₄ N (CH ₃₎ CH ₂ CH (OH) CH ₂ OC ₃ H ₆ Si (CH ₃₎ O] -Si (CH ₃ J ₃

contained.

A mechanical foam with a foam expansion of 6.5 was made from the solution. the Quarter life of the foam, d. H. the time it takes for a quarter of the weight of the liquid to drain off the foam required was 1.8 minutes.

Another foam solution was made that. 0.1 percent by weight of a hydroxyethyl cellulose with higher Molecular weight and a viscosity of 8000 cP in 1% aqueous solution at 25 ° C. and 0.85 percent by weight contained the organosilicon compound mentioned. The quarter-life of a mechanical foam with a foam expansion of 6.5 was 4.5 minutes.

Claims (1)

Patent claims: 1, foam extinguishing method for burning liquid Hydrocarbons or, to prevent ignition of flammable coals, hydrogen Application of a foam from a foamed aqueous liquid that has a surface-active Organosilicon compound, optionally together with an additional foaming agent characterized in that one applying an aqueous foamed liquid to the surface of the liquid hydrocarbon, the surface-active organosilicon compound of the general formula