DE102009057441A1 - Agent, useful for extinguishing and inerting inorganic fire material, comprises a fire extinguishing agent and an additive including hydrocarbons and oxygenated hydrocarbon compounds - Google Patents

Abstract

Agent for extinguishing and inerting an inorganic fire material, comprises: a fire extinguishing agent; and an additive including hydrocarbons or oxygenated hydrocarbon compounds, where the oxygen index of the additive is grater than the oxygen index of the inorganic fire material, and the ratio of the concentration of the fire extinguishing agent to the concentration of the additive is more than the total inerting.

Description

The invention relates to means for extinguishing and inerting inorganic fires.

The production, processing and storage of inorganic fires and other handling, such. B. the transport of these substances is associated with sometimes high risk. A number of compounds are at least, if they burn to a greater extent, not or only very difficult extinguishable. For this reason, attempts have been made to provide new extinguishing agents for extinguishing inorganic fires.

In the SU 10 97 348 a fire extinguishing agent is described in particular for chlorosilanes, in which water was added to 6 to 15% ethyl or Methylsilikonatnatrium. However, this extinguishing agent is not suitable for extinguishing all chlorosilanes, as it does not show a sufficient extinguishing effect, for example in chlorosilanes containing hydrogen.

Furthermore, from the SU 149 982 It is known to add 40 to 60% polymeric phenylsilanolsiloxane to the extinguishing agent to increase the extinguishing activity in the extinction of hydrogenchlorosilanes.

This extinguishing agent acts primarily by the formation of a cover layer. As is known, only closed cover layers have a sufficient extinguishing effect. As soon as the fire breaks through the top layer at one point, the protective effect of the remaining top layer is also abolished. For gaseous fires, topcoats are also not suitable.

In general, another problem is that chlorosilanes, as difficult-to-extinguish substances for the conventional extinguishing agents, require a very high extinguishing concentration and a large amount of extinguishing agent. The extinguishing concentrations known from the literature can not be reached with these extinguishing agents outside closed containers. This means that these extinguishing agents are ineffective outside closed containers.

For the extinguishment of chlorine-containing organosilicon compounds, an extinguishing agent mixture was developed which consists of 97% silicon tetrachloride and 0.1 to 3% hexachlorodisilane and in the SU 12 04 218 is described. Also for these agents, the problem already mentioned in the previous extinguishant applies that high amounts of extinguishing agent in relation to the amount of combustible substance are required. In this case, in addition, despite the relatively small vessel used having a diameter of 200 mm, an extinguishing time of 7 seconds was still needed.

A disadvantage of all the aforementioned means the enormously large required amount of extinguishing agent, which makes the extinguishing process ultimately so uneconomical that it is technically no longer feasible.

Furthermore, attempts have been made to increase the extinguishing effectiveness of carbon dioxide by adding halons. So will in the DD 205 336 A1 uses a fire extinguishing agent that consists of carbon dioxide and a halon. This agent is relatively expensive due to the use of halons. It is mainly used when extinguishing normally extinguishable substances and at spatially limited sources of fire. To extinguish the hard-to-extinguish, non-self-ignitable chlorosilanes a high quenching concentration is required, so that the use of this agent would be uneconomical. In addition, the extinguishing concentration required to extinguish these substances outside closed containers can not be achieved with this extinguishing agent. This means that this agent is unsuitable for extinguishing, for example, non-auto-ignitable chlorosilanes outside closed containers.

From the DE 40 14 645 A1 For example, there is known an extinguishing and inerting agent for extinguishing non-auto-ignitable chlorosilanes, which comprises, in addition to an inert gas as the second component, lower alkanes. These agents cause an additional extinguishing effect in the extinction of trichlorosilane. The additional extinguishing effect is attributed to the different boiling temperatures of the components of the extinguishing agent and the trichlorosilane. Thus, the boiling point of the additive should be between the boiling point of the fuel and the boiling point of the extinguishing agent.

The object of the invention is to provide a cost-effective means for extinguishing and inerting of inorganic fires, which is effective even with economical use and can also be used outside closed containers.

This object is achieved by an agent comprising an extinguishing agent and an additive from the group of hydrocarbons and oxygen-containing hydrocarbon compounds, wherein the oxygen index of the additive OI _{Z is} greater than the oxygen index of the inorganic fuel OI _BS and the ratio α of concentration of the extinguishing agent c _LM to the concentration of the additive c _{Z is} greater than the total inerting I _tot .

Surprisingly, it has been found that the additives mentioned, which themselves constitute organic fuels, substantially increase the extinguishing effectiveness in extinguishing inorganic fires under certain conditions. It is believed that the improvement in extinguishing effectiveness stems from the change in the combustion mechanism due to the additives.

The agent according to the invention initially acts in a known manner by lowering the concentration of the reacting substances, that is to say of the combustible substances and of the oxygen, in the flame.

By the addition of hydrocarbons or oxygen-containing hydrocarbon compounds, the oxygen index OI is now surprisingly increased so much that even with relatively small amounts of extinguishing agents, inorganic fires can be extinguished in a short time. As a result, an economical use of the agent according to the invention is possible.

Suitable extinguishing agents are inert gases, water, in particular in the form of mist or steam, dry powder, halons, haloketones or a mixture of the abovementioned extinguishing agents.

Nitrogen, carbon dioxide, argon, helium and SF ₆ have proven to be particularly suitable as inert gas. As halons, for example, the environmentally friendly non-ozone depleting halogenated hydrocarbon heptafluoropropane and as a haloketone example, CF ₃ -CF ₂ -C (O) -CF (CF ₃ ) ₂ can be used.

Suitable extinguishing powders are, on the one hand, the so-called ABC powders (eg, ammonium phosphate or ammonium sulfate based powders) and BC powders (eg, sodium bicarbonate based powders), on the other hand, metal brazing powders (eg, powders NaCl-based).

The term "extinguishing agent" is understood in the context of the present invention, the conventional extinguishing agents, which are usually used for extinguishing.

By "means" or "means for erasing and inerting" is hereinafter understood the entire means used for erasing (and inerting) means consisting of the "conventional" extinguishing agent and the additive according to the invention.

Suitable additives are hydrocarbons such as alkanes, alkenes, alkynes, aromatic hydrocarbon compounds or oxygen-containing hydrocarbons such as alkanols, ethers, ketones, aldehydes, esters, carboxylic acids or mixtures thereof.

In particular, as additives methane, ethane, propane, cyclopropane, n-butane, iso-butane, cyclobutane, n-pentane, iso-pentane, n-hexane, iso-hexane, gasoline, diesel, bitumen, benzene, toluene, xylene, Ethylbenzene, condensed aromatics, polyethylene, polypropylene, ethene, propene, butene, butadiene, pentene, methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, pentanol, hexanol, heptanol or higher alkanols, phenol, methyl tert , Butyl ether, acetone, butanone, pentanone or hexanone, benzophenone.

Likewise, alkanecarboxylic acids, in particular alkanecarboxylic acids having more than 3 carbon atoms and fatty acids, and also aromatic carboxylic acids, furthermore carboxylic acid esters such as propionic acid, butyric acid or longer-chain alkanecarboxylic esters such as fatty acid esters can be used as additives, the alcohol radical of the ester being selected from a linear or branched alkanol, for example a the aforementioned alcohols may be formed.

The additives according to the invention can also be added to the extinguishing agent in the form of emulsions or dissolved.

The proportion of the additive in the composition depends on the type and state of aggregation of the additive, the extinguishing agent and the fuel and is generally above 0.1%. For gaseous or liquid agents, the proportion of the additive in the agent is preferably between 0.5 and 15% by volume in the gas phase and more preferably between 3 and 7% by volume. For solid agents, the proportion of the additive in the agent is preferably between 0.1% and 50% and preferably between 1% and 6%.

In order to ensure that the agent according to the invention is not flammable in air at room temperature, moreover, the ratio α of the concentration of the extinguishing agent c _LM to the concentration of the additive c _{Z must be} greater than the total inerting I _tot .

The total inerting I _tot is the minimum possible concentration ratio of inert gas to additive, in which the mixture remains incombustible at any dilution with air.

Preferably, extinguishing agent and additive should be selected so that they are present in the same state of aggregation, more preferably, the boiling temperatures for gaseous extinguishing agents and additives in the liquefied state are not far apart.

The composition according to the invention is suitable for extinguishing and inerting inorganic fires, in particular for extinguishing metals, hydrogen, CS ₂ , carbon, in particular hot carbon, sulfur, inorganic sulfur compounds, phosphorus, inorganic phosphorus compounds, hydrides, silicon compounds with Si-H- or Si-Si bonds, of halosilanes and of germanium compounds, provided that their oxygen index OI _{BS is} smaller than that of the additive OI _Z.

In the field of deletion or inertization of metals, the agent according to the invention is preferably used for metals of the 1st and 2nd main group, in particular of Li, Na, K, Rb, Cs, Be, Mg, Ca and of aluminum and iron. Nevertheless, the use of the agent according to the invention is also possible with other metals. Furthermore, the agent according to the invention can be used for extinguishing or inertizing metal hydrides and metal sulfides.

The oxygen index of the fuel OI _BS is temperature-dependent. The versions apply for room temperature. If the oxygen index of the inorganic fuel OI _{BS is} above that of the additive OI _Z , the extinguishing effect is not effected. However, if the fuel itself has a significantly higher temperature than the additive and thereby the oxygen index of the fuel OI _BS drops below that of the additive OI _Z , an effective extinguishing effect can be achieved due to the higher temperature of the fuel.

A first preferred embodiment of the invention relates to a means for extinguishing the fires from the class carbon, sulfur, phosphorus, phosphorus compounds, metals, metal hydride and metal sulfides with dry powder or inert gas, in particular argon or N ₂ , or haloketones as extinguishing agent and the additive according to the invention from the group of hydrocarbons or oxygen-containing hydrocarbon compounds.

A further preferred embodiment relates to an agent for extinguishing and inerting inorganic fires with water in the form of mist or steam and the additive according to the invention from the class of hydrocarbons or oxygen-containing hydrocarbon compounds. This water-based agent is particularly suitable for extinguishing and inerting carbon, sulfur, sulfur compounds, phosphorus, phosphorus compounds, metal sulfides, hydrogen and CS ₂ . For extinguishing metals and metal hydrides, this agent is not suitable.

A third preferred embodiment relates to an agent for extinguishing the inorganic fires from the group of metals, metal hydrides and metal sulfides with extinguishing agents from the group of inert gases, haloketones, extinguishing powder or mixture thereof, which are added as an additive hydrocarbons or oxygen-containing hydrocarbon compounds. For this embodiment, suitable hydrocarbons or oxygen-containing hydrocarbon compounds are in particular methane, ethane, propane, alkanols, ethers, ketones, aldehydes, esters, carboxylic acids or mixtures thereof.

A particularly preferred variant of this embodiment relates to a means for inerting and quenching of metals and metal hydrides, in particular light metals, either with metal fire powder and polyethylene powder or with one or more of the extinguishing agent argon or nitrogen and a gaseous hydrocarbon, in particular methane, ethane, propane or butane Additive.

In addition, an agent containing the extinguishing agent CO ₂ and a gaseous hydrocarbon as an additive can also be used for extinguishing or inerting sulfur or phosphorus or compounds thereof.

In the context of the present invention, the extinguishing foam filled with inert gas, in particular a medium or high-viscosity foam, can be used as the inventive means for extinguishing and inertizing, to which is then added as additive a gaseous hydrocarbon, such as methane, ethane, propane or butane. Thus, inert gas and gaseous hydrocarbon compound are fixed together in the light foam bubbles, and thereby a new quenching and inerting agent is provided.

The extinguishing agent according to the invention can also be used successfully as a preventive protection against fires and explosions as an inerting agent.

With regard to the extinction or inertization of carbon, it should be borne in mind that the oxygen index of carbon is only so low at higher temperatures of the carbon that it is below the oxygen index OI _{Z of} the additive; ie, the means according to the invention can be used in part only for extinguishing hot carbon.

The conditions according to the invention relate to a fire in air or a gas mixture having an oxygen content, in particular up to 23% by volume.

The invention also relates to the use of the abovementioned means for extinguishing inorganic substance fires and for inerting.

The invention will be described in more detail below with reference to exemplary embodiments.

In the following Ausführungsbeisielen nitrogen, carbon dioxide and metal fire powder are used as extinguishing agents, which was added as an additive methane, propane, ethene and polyethylene.

I. Total inertization of various combinations of additives and extinguishing agents

The minimum possible ratio of extinguishing agent (or inert gas) to additive, in which the mixture remains incombustible at any dilution with air, is called total inerting I _tot . It can be determined by checking whether the mixture is combustible in air or it can be read from inerting diagrams. Many inertization diagrams have been published in the literature, for example in Lewis, v. Elbe: "Combustion, Flames and Explosions of Gases", Academy Pess Inc. New York, London 1961, 2 ; VT Monachov: "Methods for Investigating the Fire Hazard of Substances", Staatsverlag der DDR, Berlin 1984, p. 118 ; WA Bondar, WI Gorschkow, BG Popov, VN Werjowkin: "Static Electricity and Fire Protection", State Publishing House of the GDR, Berlin 1977, p. 106, 161 ,

An explosion does not take place or the agent is incombustible if the concentrations are not within the explosive range and do not cut it even when diluted with air. The limiting case of total inertization is when the line of the dilution process just touches the line of the blast area. At the point of contact, the additional concentration and the extinguishing agent or inert gas concentration can be read off and put into relation in the inertisation diagram.

In part, the concentrations of total inertization are also published as such. However, this information differs from the exact determination on the inertization diagram, since - depending on the author - different high safety factors are included.

In the context of the present invention, the "total inerting I _tot " is to be determined exactly from the inertization diagram.

• ~ = Schätzwert

Table 1 shows the limits for the inerting of flammable gases and vapors at 1 bar total pressure (literature values), which must be safely exceeded for total inerting of some substances. (Source: Technical Rules for Industrial Safety TRBS 2152 Part 2, Technical Rules for Hazardous Substances TRGS 722, "Avoidance or Reduction of Hazardous Explosive Atmospheres (Edition 08/2006) , These values already include a safety factor. Total inertisation I _dead Flammable substance Temperature in ° C Minimum value of the ratio of the molar parts of inert gas (N ₂ or CO ₂ ) and additive (Z) for inerting with any addition of air N ₂ / Z CO ₂ / Z butane 20 27 - butane 20 28 13 Ethan 20 21 11 ethylene 20 24 13 methane 20 11 5 pentane 20 ~ 42 - propane 20 26 13 propylene 20 23 12 Gasoline 20 ~ 42 - hydrogen 20 17 12 methyl ethyl ketone 20 26 - ethanol 20 17 - methanol 20 7 - Propanol-1 20 19 - 2-propanol 20 25 - Table 1

• ~ = Estimated value

Thus, the literature values which include a safety factor give the maximum concentration of the additive in which the inert gas containing CO ₂ and N ₂ contains:

II. Determination of the oxygen index (OI) of various fires

The gaseous extinguishing agent was tested in a vertical glass tube through which an extinguishing agent-air mixture flows. The test was carried out on the basis of DIN EN ISO 4589 and ASTM D 2863-06a (Determination of the oxygen index).

As combustible substances were inorganic and organic gaseous, liquid and solid fires. The liquids were placed in a small 10 mm diameter cup in the middle of the tube. Through a wick, the substances came in contact with the surrounding gas.

If the concentration of the gas is constant over time, the ignition of the vapors takes place at the wick by means of an electric igniter or a hydrogen flame.

The gases to be tested are introduced through a bent glass tube into the vertical glass tube.

The solids were positioned in the form of a bed (in the case of the red phosphor) or in the form of a candle (in the case of sulfur) in the middle of the tube.

Depending on the set extinguishing agent concentration, the flame extinguishes again on the wick after some time. The extinguishing agent concentrations that cause certain identical burn times are defined as extinguishing concentrations. The converted oxygen concentration is the oxygen index.

execution

The implementation is described in more detail below using the example of carbon dioxide with the addition of propane.

oder
unter Zusatz von Kohlendioxid und Propan

The procedure was carried out in the oxygen index apparatus (total volume flow = 0.1473 l / s)
with the addition of carbon dioxide

or
with the addition of carbon dioxide and propane

The gas flows were adjusted by means of rotameters.

The wick method was used for the liquids. The ignition took place by means of a hydrogen flame.

The gases were introduced into the apparatus with the aid of a curved glass tube nozzle (inner diameter 4 mm) so that the flame size was 2-3 cm. Propane was ignited by hydrogen flame. The ignition of the hydrogen was carried out at elevated gas flow with a gas lighter above the gauge (room air). After ignition, the flame was then immediately reduced down to 2-3 cm.

The solids were placed in a metal cup on a stainless steel pedestal in the apparatus. For this purpose, a sulfur candle with wick was first cast from the sulfur powder. The red phosphorus was filled directly into the metal cup as a powder bed and the oxide layer was loosened with a wire in between.

Ignition was by means of a hydrogen flame.

Calculation basis

• V.

  - volume flow [Is ^-1 ]

  V. _Z

  - Volume flow of the additive [Is ^-1 ]

  V. _ges.

  - total volume flow [Is ^-1 ]

• V. _ges. = 0.1473 Is ^-1 (glass tube)
  
• V. _O₂ = OI · V. _ges.

V ._Z = 1 / α·V ._CO₂ For carbon dioxide as an extinguishing agent then also applies V. _N₂ = 3.815 · V. _O₂

V. _Z = 1 / α · V. _CO₂

The oxygen index (OI) is the volume fraction of oxygen in the total volume flow at which the flame burns as accurately as possible for 3 minutes.

For nitrogen as extinguishing agent then also applies V. _Z = [1 / α * V. _ges. (1 - 4.815 · OI)]: [1 + 1 / α] V. _CO₂ = 0 V. _N₂ = V. _ges. - V. _O₂ - V. _Z

In the metal firing tests, the oxygen index apparatus is not used, but the extinguishing powder with the additive is added directly to the preheated burning sodium.

III. embodiments

a) Comparison of the extinguishing effect of various fires when extinguished with carbon dioxide or carbon dioxide with the addition of propane (C ₃ H ₈ )

b) Comparison of the extinguishing effect of various fires when extinguished with nitrogen or nitrogen with the addition of propane (C ₃ H ₈ ) or ethene.

The measurements show a significant increase in the oxygen index OI when adding hydrocarbons for the fuels sodium, carbon disulfide, sulfur, phosphorus (red) and hydrogen.

IV. Extinguishing Tests of Sodium Embers with Mixtures of Metal Fire Powder (MBP) and Polyethylene Powder (PE) as Extinguishing Media

Test Description:

As fuel is sodium (Na) in a porcelain crucible in the oven for 10 min. preheated at 250 ° C. On a copper wire loop, first a small amount of Na is ignited with the help of a hydrogen flame and thus the Na in the crucible.

The extinguishing agent used is metal fire powder (MBP) with additions of polyethylene powder (PE) as additive and pure PE.

The agent is added to the burning sodium by means of a small funnel until the sodium quenches. Subsequently, the required mass of the extinguishing agent with addition (m _Lm ) is balanced.

First, the experiments are carried out with the fuel mass (m _Na ) 1 g of sodium and then checked in part with 2 g of sodium.

The evaluation and results are summarized in the following table:

Result:

The optimum concentration ratio of additive (polyethylene) to extinguishing agent is 3%.

If the addition of polyethylene is too high, the polyethylene burns itself. Concentrations above 6% of polyethylene should not be used because of the risk of explosion.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• SU 1097348 [0003]
• SU 149982 [0004]
• SU 1204218 [0007]
• DD 205336 A1 [0009]
• DE 4014645 A1 [0010]

Cited non-patent literature

• Lewis, v. Elbe: "Combustion, Flames and Explosions of Gases", Academy Pess Inc. New York, London 1961, 2 [0044]
• VT Monachov: "Methods for investigating the fire hazard of substances", Staatsverlag der DDR, Berlin 1984, p. 118 [0044]
• WA Bondar, WI Gorshkov, BG Popov, VN Werjowkin: "Static Electricity and Fire Protection", State Publishing House of the GDR, Berlin 1977, p. 106, 161 [0044]
• Technical Rules for Industrial Safety TRBS 2152 Part 2, Technical Rules for Hazardous Substances TRGS 722, "Avoidance or Reduction of Hazardous Explosive Atmospheres (Edition 08/2006) [0048]
• DIN EN ISO 4589 [0050]
• ASTM D 2863-06a [0050]

Claims (11)

Means for extinguishing and inerting inorganic fires BS, which comprises an extinguishing agent LM and an additive Z from the group of hydrocarbons and oxygen-containing hydrocarbon compounds, wherein the oxygen index of the additive OI _{Z is} greater than the oxygen index of the inorganic firing OI _BS and the ratio α from concentration of the extinguishing agent c _LM to the concentration of the additive c _{Z is} greater than the total inerting I _tot . Composition according to claim 1, characterized in that the extinguishing agent is an inert gas, water, in particular in the form of mist or steam, dry powder, a halon, a haloketone or a mixture of the aforementioned extinguishing agents. Composition according to claim 2, characterized in that the inert gas is nitrogen, carbon dioxide, argon, helium or SF ₆ and the quenching powders from the group of ABC powder, BC powder or metal fire powder are selected. Composition according to one of the preceding claims, characterized in that the additives from the group of hydrocarbons are alkanes, alkenes, alkynes, aromatic hydrocarbon compounds and the oxygen-containing hydrocarbon compounds from the group of alkanols, ethers, ketones, aldehydes, esters, carboxylic acids or mixtures thereof. Composition according to claim 4, characterized in that the additives are selected from the group of methane, ethane, propane, cyclopropane, n-butane, iso-butane, cyclobutane, n-pentane, iso-pentane, n-hexane, iso-hexane, Gasoline, diesel, bitumen, benzene, toluene, xylene, ethylbenzene, condensed aromatics, polyethylene, polypropylene, ethene, propene, butene, butadiene, pentene, methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, pentanol, Hexanol, heptanol or the higher alkanols, phenol, methyl tert. Butyl ether, acetone, butanone, pentanone or hexanone, benzophenone, the alkanecarboxylic acids, in particular alkanecarboxylic acids having more than 3 carbon atoms and fatty acids, the aromatic carboxylic acids and the carboxylic acid esters. Agent according to one of the preceding claims, characterized in that the inorganic flammable metals, hydrogen, CS ₂ , carbon, in particular hot carbon, sulfur, inorganic sulfur compounds, phosphorus, inorganic phosphorus compounds, hydrides, silicon compounds with Si-H or Si-Si bonds or halosilanes. Agent according to one of the preceding claims for extinguishing the fires from the class carbon, sulfur, phosphorus, phosphorus compounds, metals, metal hydride and metal sulfides with extinguishing agents from the group extinguishing powder, inert gas, in particular CO ₂ , argon or N ₂ and haloketone, which Hydrocarbon or an oxygen-containing hydrocarbon compound is added as an additive. Agent according to one of claims 1 to 6 for extinguishing and inerting inorganic fires excluding metals and metal hydrides with water in the form of mist or vapor and an additive from the group of hydrocarbons and oxygen-containing hydrocarbon compounds, in particular for extinguishing and inerting of carbon, Sulfur, sulfur compounds, phosphorus, phosphorus compounds, metal sulfides, hydrogen, CS ₂ , Si-Si containing and Si-H containing compounds. Agent according to one of claims 1 to 6 for extinguishing inorganic flammable substances from the group of metals, metal hydride and metal sulfides with extinguishing agents from the group of inert gases, haloketones, extinguishing powder or their mixture, which are added as an additive hydrocarbons or oxygen-containing hydrocarbon compounds. Agent according to one of Claims 1 to 6 or 9 for extinguishing and inerting metals and metal hydrides with the extinguishing agent metal fire powder and polyethylene powder as additive or with one or more of the extinguishing agents argon, nitrogen and a gaseous hydrocarbon, in particular methane, ethane, propane or butane, Additionally. Means according to 1 to 6 for extinguishing and inerting of sulfur, phosphorus or their compounds, characterized in that the extinguishing agent is CO ₂ , to which a gaseous hydrocarbon is added as an additive.