DE102009057441B4 - Use of an agent for extinguishing and inerting inorganic fires - Google Patents

Abstract

Use of an agent for extinguishing and inerting inorganic fuels BS, which comprises an extinguishing agent LM and an additive Z from the group of hydrocarbons and oxygen-containing hydrocarbon compounds, the oxygen index of the additive OIZ being greater than the oxygen index of the inorganic combustible OIBS and the ratio α from the concentration of the extinguishing agent cLM to the concentration of the additive cZ is greater than the total inertization Itat, the inorganic fuel from the group of metals, hydrogen, CS2, carbon, sulfur, inorganic sulfur compounds, phosphorus, inorganic phosphorus compounds and hydrides, with the exclusion of Si Hydrides is selected and the extinguishing agent is an inert gas, water, a halon, a halogen ketone or a mixture of the aforementioned extinguishing agents.

Description

The invention relates to the use of an agent 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.

The DE 1 190 796 B teaches a liquid for the extinguishment of fires of all kinds, especially dry fires, hydrocarbon fires and also carbon disulfide based on aqueous solutions of potassium salts of organic acids, which to improve the extinguishing effect in the extinction of hydrocarbons and sulfur compounds, a small amount of an aliphatic alcohol can be added with low molecular weight.

From the US 2 346 627 A It is known to extinguish light metal fires with granulated carbon as the extinguishing agent, which is coated with an organic substance with a high flash point and a high boiling point such as mineral or vegetable oil, the carbon for covering the light metal and the oil for evaporation and displacement of the Oxygen serves. However, sporadic flames can occur when deleting. However, since these are not continuous flames, they do not have to be cleared.

The GB 518 717 A teaches the use of pasty or semi-liquid agents to extinguish light metal fires, which contain a mineral, vegetable oil or wax in addition to a powdery inorganic substance such as talc or diatomaceous earth. The deletion takes place through the formation of cover layers, whereby in the case of the inflammation of the mineral, vegetable oil or wax this further fire is extinguished by the further addition of these oils / waxes.

In the SU 10 97 348 A1 a fire extinguishing agent is described in particular for chlorosilanes, in which water 6 to 15% sodium ethyl or Natriummethylsiliconat was added. 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 A1 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 A1 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 used a fire extinguishing agent that consists of carbon dioxide and a halon consists. 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 and the DD 295 554 A5 there is known a quenching and inerting agent for quenching non-auto-ignitable chlorosilanes, which comprises lower alkanes in addition to an inert gas as the second component. 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.

From the JP 000H10314335 A It is known to dry a mixture of 58% dry sodium carbonate, 21% dry potassium carbonate and 21% dry lithium carbonate together with a grinding aid and a surface finish for two hours at 140 ° C and then add to this agent 5% polyethylene. The resulting mixture is used as extinguishing agent for metal fires. With this agent, a 2 to 3 mm thick fire-extinguishing cover layer is to be achieved, disadvantageous, however, is the complex production of the extinguishing agent.

From the EP 0 803 468 A1 For example, a method of stabilizing hydridic silane is known.

The object of the invention is to provide a cost-effective means for use in 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 a gaseous or liquid 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 firing OI _BS and the ratio α Concentration of the extinguishing agent c _LM to the concentration of the additive c _Z 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 acts initially in a known manner, by lowering the concentration of the reacting substances, ie the combustible substances and 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 is possible.

Suitable extinguishing agents are inert gases, water mist or steam, halons or haloketones or mixtures thereof.

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.

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.

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 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 extinguishing 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.

In order to ensure that the agent 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 is suitable for extinguishing and inerting inorganic fuels from the group of metals, hydrogen, CS ₂ , carbon, in particular hot carbon, sulfur, inorganic sulfur compounds, phosphorus, inorganic phosphorus compounds, hydrides with the exclusion of Si hydrides and germanium compounds, if so whose oxygen index OI _{BS is} smaller than that of the additive OI _Z.

In the field of deletion or inertization of metals, the agent 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 is also possible with other metals. Furthermore, the agent can be used to quench or inertize 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, the phosphorus compounds, the metals, metal hydride and metal sulfides with inert gas, in particular argon or N ₂ , or haloketones as extinguishing agent and the addition from the group the hydrocarbons or the oxygen-containing hydrocarbon compounds.

A further preferred embodiment relates to a means for extinguishing and inerting inorganic fuels with water in the form of mist or steam and the addition of the class of hydrocarbons or oxygen-containing hydrocarbon compounds. This water vapor or mist-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 a means for extinguishing the inorganic flammable substances from the group of metals, metal hydrides and metal sulfides with extinguishing agents from the group of inert gases, the haloketones, or their mixture, 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.

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, an extinguishing foam filled with inert gas, in particular a medium or high-viscosity foam, can be used as the means for extinguishing and inertizing, to which a gaseous hydrocarbon such as methane, ethane, propane or butane is then added as additive. 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 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 that the funds can be used partially only for the eradication of hot carbon.

The conditions relate to a fire in air or a gas mixture with an oxygen content, in particular up to 23 vol .-%.

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

In the following examples, the extinguishing agents used are nitrogen and carbon dioxide, to which methane, propane and ethene have been added as additives.

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. Chem. 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.

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 operational safety TRBS 2152 Part 2, Technical Rules for Hazardous Substances TRGS 722, "Avoidance or restriction 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 n-butane 20 27 - i-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, from the literature values which include a safety factor, the maximum concentration of the additive in the agent containing the relevant inert gas CO ₂ and N ₂ results:

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 in accordance with 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 [ls ^-2 ]

  V. _Z

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

  V. _ges.

  - total volume flow [ls ^-1 ]

For carbon dioxide as an extinguishing agent then also applies

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

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.

Claims (11)

Use of an agent for extinguishing and inerting inorganic fuels 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 fuel OI _BS and the Ratio α from the concentration of the extinguishing agent c _LM to the concentration of the additive c _Z greater than the total inerting I _tat , wherein the inorganic fuel from the group metals, hydrogen, CS ₂ , carbon, sulfur, inorganic sulfur compounds, phosphorus, inorganic phosphorus compounds and hydrides , excluding Si hydrides and the extinguishing agent is an inert gas, water, a halon, a haloketone or a mixture of the aforementioned extinguishing agents. Use of a composition according to claim 1, characterized in that the inert gas is nitrogen, carbon dioxide, argon, helium or SF ₆ . Use of a composition according to any one of the preceding claims, characterized in that the additive from the group of hydrocarbons 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 are. Use of a composition according to claim 3, characterized in that the additive is 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 higher alkanols, phenol, methyl tert. Butyl ether, acetone, butanone, pentanone or hexanone, benzophenone, alkanecarboxylic acids, especially alkanecarboxylic acids having more than 3 carbon atoms and fatty acids, aromatic carboxylic acids and carboxylic acid esters. Use of a composition according to one of the preceding claims for extinguishing the fires from the class carbon, sulfur, phosphorus, phosphorus compounds, metals, metal hydrides and metal sulfides with extinguishing agents from the group inert gas, in particular CO _2, argon or N ₂ , and haloketone, which a hydrocarbon or an oxygen-containing hydrocarbon compound is added as an additive. Use of a composition according to any one of claims 1 to 4 for extinguishing and inerting inorganic fuels, 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. Use of a composition according to claim 6 for extinguishing and inerting carbon, sulfur, sulfur compounds, phosphorus, phosphorus compounds, metal sulfides, hydrogen and CS ₂ . Use of a composition according to any one of claims 1 to 4 for extinguishing the inorganic flammable substances from the group of metals, metal hydrides and metal sulfides with extinguishing agents from the group of inert gases, the haloketones or their mixture, which are added as an additive hydrocarbons or oxygen-containing hydrocarbon compounds. Use of an agent according to one of claims 1 to 4 or 8 for extinguishing and inerting metals and metal hydrides with argon and / or nitrogen as extinguishing agent and a gaseous hydrocarbon, in particular methane, ethane, propane or butane, as additive. Use of a composition according to any one of claims 1 to 4 for extinguishing and inerting sulfur, phosphorus or compounds thereof, characterized in that the extinguishing agent is CO ₂ , to which a gaseous hydrocarbon is added as additive. Use of a composition according to claim 1, characterized in that the water is water in the form of mist or steam.