EP0069393A1 - Method for the early detection of carbonic fires in recipients containing dust of brown coal by detection of methane - Google Patents

Method for the early detection of carbonic fires in recipients containing dust of brown coal by detection of methane Download PDF

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Publication number
EP0069393A1
EP0069393A1 EP82106076A EP82106076A EP0069393A1 EP 0069393 A1 EP0069393 A1 EP 0069393A1 EP 82106076 A EP82106076 A EP 82106076A EP 82106076 A EP82106076 A EP 82106076A EP 0069393 A1 EP0069393 A1 EP 0069393A1
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Prior art keywords
dust
fires
detection
gas
gases
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German (de)
French (fr)
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EP0069393B1 (en
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Erhard Wolfrum
Hans-Peter Päffgen
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Rheinbraun AG
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Rheinische Braunkohlenwerke AG
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    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00Fire alarms; Alarms responsive to explosion
    • G08B17/10Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/117Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means by using a detection device for specific gases, e.g. combustion products, produced by the fire

Definitions

  • the invention relates to a method for the detection of smoldering fires in containers containing lignite dust, with the aid of which certain gases which form in the lignite dust and possibly escape therefrom can be measured with a suitable detector and used as "indicator gases" for early detection of smoldering fire.
  • the method of measuring the carbon monoxide (CO) formed underground is used successfully for the early detection of fires or smoldering fires in hard coal.
  • CO carbon monoxide
  • BK dust brown coal dust
  • the carbon monoxide content of the gas volume above the bed is currently also being determined.
  • the results of this method are not entirely clear, since CO and carbon dioxide (C0 2 ) occur as degradation products of functional groups in brown coal even when the ignition temperature of the brown coal has not yet been reached.
  • CO or C0 2 can, however, also occur as a decomposition product of functional groups in lignite if the ignition temperature of the coal has not yet been reached. This fact makes for practice, e.g. B. for a dust bunker, the specification of a limit concentration is necessary, from which the probability of the existence of a smoldering fire in a lignite dust bed is given.
  • H 2 and CH 4 only appear when a smoldering fire has occurred in the bed.
  • This detection of a smoldering fire by detecting H 2 and CH 4 is, in addition to the previous early detection via CO, a further developed method for the detection of smoldering fires in lignite dust. It is not absolutely necessary to state a limit concentration for H 2 and CH 4 , since these gases are specific for the presence of a smoldering fire. However, since it is difficult to measure the hydrogen content under operational conditions, the measurement of CH 4 is particularly suitable for the detection of smoldering fires.
  • a detector for detecting the gases in question is attached to the container containing lignite dust in such a way that it either probes into the discharge nozzle of the loading device engages container or in the interior above the emptying nozzle, wherein the probe can reach both in the area of the dumping height and in the gas space above the dumping height.
  • a plurality of such probes can also be provided spaced apart from one another and / or distributed in the circumferential direction over the length of the container.
  • the probes can either have detectors themselves or can be provided with connections which supply a mostly small amount of gas required for measurement to a suitable device, for example a gas chromatograph or other gas analyzer.
  • a suitable device for example a gas chromatograph or other gas analyzer.
  • the method according to the invention was first tested in the laboratory. For this purpose, smoldering fires were generated in a dust bed by heating the bed and introducing air.
  • the aim of the laboratory method was to compare the composition of the gases formed by a smoldering fire in the lignite dust with a gas that is formed when there is no smoldering fire.
  • the temperature in the bed was measured using thermocouples. After the above-mentioned temperatures in the bed had been reached, preheated air was introduced into the BK dust bed over a period of approximately 7.5 hours. The air flow rate was approx. 0.1 l / min.
  • the composition of the gas leaving the test apparatus was determined by gas chromatography with regard to H 21 CH 4 , CO and CO 2 .
  • FIG. 1 The results of the tests are shown in a diagram in FIG. 1.
  • the representation is not to scale, and in view of the relatively low values for hydrogen and methane.
  • the diagram shows the proportions of the individual gas components H 2 ' CH 4' CO and C0 2 in volume percent (vol.%) Depending on the test temperature.
  • H 2 and CH 4 While the gas components CO and C0 2 are already present at temperatures below the ignition temperature, H 2 and CH 4 only appear when the ignition temperature is reached in order to reach a maximum value relatively quickly and then decrease in concentration again. The relatively pronounced increase in the concentration of gases H 2 and CH 4 is therefore particularly well suited for the early detection of a smoldering fire.
  • the most suitable detection is the gas which has the highest concentration in the carbonization gas.
  • a smoldering fire detection of the gases CO and CO 2 which are present in higher concentrations, is problematic in practice, since a limit concentration must be defined, which, as stated, again depends on many individual influences.
  • the "indicator gases” H 2 and CH 4 and higher hydrocarbons can largely be used specifically for smoldering fire identification. Due to the higher concentration of H 2 in the carbonization gas, this gas should be more suitable than CH 4 . However, if a selection is made between the two "indicator gases” after practical determination or identification, only CH 4 remains as the “indicator gas” of choice.
  • a lignite dust bunker 1 narrows in its lower part to form a funnel 2 which opens into an outlet element 3.
  • This outlet member 3 consists in detail of a cellular wheel 4 with drive 5 and a bellows 6 for adaptation to different customers.
  • the dust bunker 1 at the level of its funnel 2 has a ring line 7 for supplying compressed air, so that the bed inside the dust bunker can be loosened if necessary.
  • a CH 4 -IR gas analyzer (not shown) reaches with a probe 8 into the emptying neck of the container.
  • three identical probes 9 are attached at almost the same distance and possibly distributed in the circumferential direction over the axial length of the container, the probes projecting both into the area of the dust bed 10 and into the gas space 11 above the bed. These probes are also connected to a CH 4 -IR gas analyzer. Between probe 8 or probes 9 and the CH 4 -IR-. Gas analyzers are built-in dust filters (not shown) to protect the measuring devices.
  • the basic CH 4 value determined in probe 9 in the bunker was 5-33 ppm
  • the basic CH 4 value measured in probe 8 when the bunker was emptied was approximately 10 ppm.

Abstract

For the early detection of fires smouldering in containers containing lignite dust, the presence of gas containing hydrogen and/or hydrocarbons is measured within the containers, respectively around the containers, those gases not being normally present in lignite dust or being present in very small amounts which are hardly detectable and appearing only with the formation of smouldering fires.

Description

Die Erfindung betrifft ein Verfahren zum Nachweis von Schwlebränden in Braunkohlenstaub enthaltenden Behältern, mit dessen Hilfe bestimmte, sich in dem Braunkohlenstaub bildende und ggf. draus austretende Gase mit einem geeigneten Detaktor gemessen und als "Indikator-Gase" zur Schwelbrand-Früherkennung verwendet werden können.The invention relates to a method for the detection of smoldering fires in containers containing lignite dust, with the aid of which certain gases which form in the lignite dust and possibly escape therefrom can be measured with a suitable detector and used as "indicator gases" for early detection of smoldering fire.

Für die Früherkennung von Bränden oder Schwelbränden in der Steinkohle wird die Methode der Messung des dabei gebildeten Kohlenmonoxids (CO) unter Tage erfolgreich angewandt. Zur Schwelbrandfrüherkennung während der Lagerung von Braunkohlenstaub (BK-Staub) in Bunkern wird gegenwärtig ebenfalls der Kohlenmonoxid-Gehalt des über der Schüttung befindlichen Gasvolumens bestimmt. Die Ergebnisse dieser Methode sind jedoch nicht vollkommen eindeutig, da CO und Kohlendioxid (C02) als Abbauprodukte funktioneller Gruppen der Braunkohle auch dann auftreten, wenn die Zündtemperatur der Braunkohle noch nicht erreicht ist.The method of measuring the carbon monoxide (CO) formed underground is used successfully for the early detection of fires or smoldering fires in hard coal. For early detection of smoldering fire during the storage of brown coal dust (BK dust) in bunkers, the carbon monoxide content of the gas volume above the bed is currently also being determined. However, the results of this method are not entirely clear, since CO and carbon dioxide (C0 2 ) occur as degradation products of functional groups in brown coal even when the ignition temperature of the brown coal has not yet been reached.

Für die sichere Lagerung, den Transport und den Umfang mit Braunkohlenstaub ist es jedoch wegen dessen Eigenschaft der leichten Entzündbarkeit bzw. Neigung zur Selbstentzündung unbedingt erforderlich, das Vorhandensein von Schwelbränden im Staub möglichst frühzeitig zu erkennen. Die Frühzeitigkeit der Erkennung ist besonders geboten, da einmal in Brand geratener Braunkohlenstaub nur mit Mühe wieder gelöscht werden kann.For safe storage, transport and the extent of lignite dust, however, it is due to its property of easy flammability or tendency to Self-ignition is absolutely necessary to detect the presence of smoldering fires in the dust as early as possible. Early detection is particularly advisable, since lignite dust that has caught fire can only be extinguished with difficulty.

Die Zunahme der kommerziellen Nutzung von Braunkohlenstaub in den letzten Jahren hat es erforderlich gemacht, den Staub auf Vorrat zu lagern, zwischenzulagern und meistens auch über bisweilen weite Strecken zu transportieren.The increase in the commercial use of lignite dust in recent years has made it necessary to store the dust in stock, to store it temporarily and, in most cases, to transport it over long distances.

Die Einhaltung der notwendigen Sicherheitsbestimmungen führte zur Formulierung der der Erfindung zugrunde liegenden Aufgabe, wonach eine Methode anzugeben ist, die das Vorhandensein von Schwelbränden innerhalb von in Behältern befindlichem Braunkohlenstaub zu einem möglichst frühen Zeitpunkt und mit grosser betrieblicher Sicherheit gewährleistet.Compliance with the necessary safety regulations led to the formulation of the object on which the invention is based, according to which a method is to be specified which guarantees the presence of smoldering fires within brown coal dust contained in containers at the earliest possible point in time and with great operational safety.

Bei der Beobachtung der Schüttungen von Braunkohlenstaub wurde nun gefunden, dass darin Wasserstoff (H2) bzw. Methan (CH4) enthaltende Gase.normalerweise fast überhaupt nicht oder nur in fast nicht mehr nachweisbar geringen Mengen auftreten. Anders verhält es sich mit CO bzw. C02, die stets vorhanden sind.When observing the fillings of lignite dust, it was found that gases containing hydrogen (H 2 ) or methane (CH 4 ) normally do not occur at all or only in small amounts that are almost undetectable. It is different with CO or C0 2 , which are always present.

Grössere Mengen an CO bzw. C02 können sich erst in dem Augenblick bilden, in dem innerhalb der Staubschüttung ein Schwelbrand entsteht.Larger amounts of CO or C0 2 can only form at the moment when a smoldering fire occurs within the bed of dust.

CO bzw. C02 können aber als Abbauprodukt funktioneller Gruppen der Braunkohle auch dann auftreten, wenn die Zündtemperatur der Kohle noch nicht erreicht ist. Dieser Sachverhalt macht für die Praxis, z. B. für einen Staubbunker, die Angabe einer Grenzkonzentration notwendig, ab der die Wahrscheinlichkeit des Vorhandenseins eines Schwelbrandes in einer Braunkohlenstaub-Schüttung gegegeben ist.CO or C0 2 can, however, also occur as a decomposition product of functional groups in lignite if the ignition temperature of the coal has not yet been reached. This fact makes for practice, e.g. B. for a dust bunker, the specification of a limit concentration is necessary, from which the probability of the existence of a smoldering fire in a lignite dust bed is given.

Grundsätzlich ist es so, dass die Werte für Grenzkonzentration an jedem Staubbehälter und für jede Staubsorte unterschiedlich sein und auch noch vom jeweiligen Füllungsgrad eines Behälters abhängen können.It is basically the case that the values for the limit concentration on each dust container and for each dust type are different and can also depend on the respective degree of filling of a container.

Es wurde in Laborversuchen festgestellt, dass H2 und CH4 erst dann auftreten, wenn ein Schwelbrand in der Schüttung entstanden ist. Dieser Nachweis eines Schwelbrandes über eine Detektion von H2 und CH4 ist neben der bisherigen Früherkennung über CO eine weiterentwickelte Methode zur Erkennung von Schwelbränden in Braunkohlenstaub. Die Angabe einer Grenzkonzentration ist für H2 und CH4 nicht unbedingt notwendig, da diese Gase für das Vorhandensein eines Schwelbrandes spezifisch sind. Da jedoch eine Messung des Wasserstoffgehaltes unter betrieblichen Bedingungen schwierig ist, bietet sich die Messung von CH4 zur Detektion von Schwelbränden als besonders geeignet an.It was found in laboratory tests that H 2 and CH 4 only appear when a smoldering fire has occurred in the bed. This detection of a smoldering fire by detecting H 2 and CH 4 is, in addition to the previous early detection via CO, a further developed method for the detection of smoldering fires in lignite dust. It is not absolutely necessary to state a limit concentration for H 2 and CH 4 , since these gases are specific for the presence of a smoldering fire. However, since it is difficult to measure the hydrogen content under operational conditions, the measurement of CH 4 is particularly suitable for the detection of smoldering fires.

Infolgedessen konnte zur Lösung der der Erfindung zugrunde liegenden Aufgabe angegeben werden, dass die Anwesenheit von CH4 und/oder höhere Kohlenwasserstoffe enthaltenden Gasen in Braunkohlenstaub gemessen wird.As a result, to achieve the object on which the invention is based, it was possible to state that the presence of gases containing CH 4 and / or higher hydrocarbons in lignite dust is measured.

Bei einer Vorrichtung zur Durchführung des erfindungsgemässen Verfahrens wird an dem Braunkohlenstaub enthaltenden Behälter ein Detektor zum Aufspüren der in Frage kommenden Gase derart angebracht, dass er mit einer Sonde entweder in den Entleerungsstutzen des Behälters eingreift oder in den Innenraum oberhalb des Entleerungsstutzens, wobei die Sonde sowohl im Bereich der Schütthöhe als auch in den Gasraum oberhalb der Schütthöhe hineingreifen kann. Selbstverständlich können über die Länge des Behälters auch mehrere derartige Sonden im gegenseitigen Abstand voneinander und/oder auch in Umfangsrichtung verteilt vorgesehen sein.In a device for carrying out the method according to the invention, a detector for detecting the gases in question is attached to the container containing lignite dust in such a way that it either probes into the discharge nozzle of the loading device engages container or in the interior above the emptying nozzle, wherein the probe can reach both in the area of the dumping height and in the gas space above the dumping height. Of course, a plurality of such probes can also be provided spaced apart from one another and / or distributed in the circumferential direction over the length of the container.

Die Sonden können entweder selbst Detaktoren aufweisen oder aber mit Anschlüssen versehen sein, welche eine zur Messung erforderliche, meist geringe Gasmenge einem geeigneten Gerät, beispielsweise einem Gaschromatographen oder anderen Gasanalysatoren zuführen.The probes can either have detectors themselves or can be provided with connections which supply a mostly small amount of gas required for measurement to a suitable device, for example a gas chromatograph or other gas analyzer.

Das erfindungsgemässe Verfahren wurde zunächst labormässig erprobt. Hierzu wurden in einer Staubschüttung Schwelbrände dadurch erzeugt, dass die Schüttung aufgeheizt und Luft eingeleitet wurde. Dabei hatte das labormässige Verfahren zum Ziel, die Zusammensetzung der durch einen Schwelbrand im Braunkohlenstaub gebildeten Gase mit einem Gas zu vergleichen, das dann gebildet wird, wenn kein Schwelbrand vorhanden ist.The method according to the invention was first tested in the laboratory. For this purpose, smoldering fires were generated in a dust bed by heating the bed and introducing air. The aim of the laboratory method was to compare the composition of the gases formed by a smoldering fire in the lignite dust with a gas that is formed when there is no smoldering fire.

Bei dem Versuch wruden ca. 1200 bis 1300 g BraunkohlenStaub aus der Produktion einer Brikettfabrik in ein von aussen beheizbares Glasgefäss'geschüttet, welches ein Fassungsvermögen von ca. 2,5 1 aufweist.In the experiment, approximately 1200 to 1300 g of lignite dust from the production of a briquette factory were poured into a glass vessel which can be heated from the outside and which has a capacity of approximately 2.5 l.

Danach wurde der Staub auf die in nachfolgender Tabelle wiedergegebenen Anfangstemperaturen erhitzt:

Figure imgb0001
The dust was then heated to the initial temperatures shown in the table below:
Figure imgb0001

Die Temperatur in der Schüttung wurde mit Hilfe von Thermoelementen gemessen. Nachdem die oben angegebenen Temperaturen in der Schüttung erreicht waren, wurde vorgewärmte Luft über einen Zeitraum von ungefähr 7,5 Stunden in die BK-Staubschüttung eingeleitet. Der Luftdurchsatz betrug ca. 0,1 l/min. Die Zusammensetzung des die Versuchsapparatur verlassenden Gases wurde gaschromatographisch hinsichtlich H21 CH4, CO und C02 ermittelt.The temperature in the bed was measured using thermocouples. After the above-mentioned temperatures in the bed had been reached, preheated air was introduced into the BK dust bed over a period of approximately 7.5 hours. The air flow rate was approx. 0.1 l / min. The composition of the gas leaving the test apparatus was determined by gas chromatography with regard to H 21 CH 4 , CO and CO 2 .

Während der Versuche 1 bis 3 bildeten sich durch Selbstoxidation, verbunden mit einem raschen Temperaturanstieg in den Staubschüttungen Schwelbrände. Im Verlauf der Versuche 4 bis 6 konnten auch nach 7,5 Stunden Luftzufuhr keine Schwelbrände beobachtet werden. Die die Schüttung verlassenden Gase wurden analysiert; bei den Versuchen 1 - 3 wurde festgestellt, dass H2 und CH4 austraten und der Anteil an CO und CO2 bei Bildung eines Schwelbrandes auf einen Maximalwert anstieg.During experiments 1 to 3, smoldering fires formed as a result of self-oxidation combined with a rapid rise in temperature in the dust beds. In the course of experiments 4 to 6, no smoldering fires were observed even after 7.5 hours of air supply. The gases leaving the bed were analyzed; In experiments 1-3, it was found that H 2 and CH 4 emerged and the proportion of CO and CO 2 rose to a maximum value when a smoldering fire formed.

Hohe H2-Konzentrationen wurden jedoch nur im Zusammenhang mit der Ausbildung von Schwelbränden festgestellt, dagegen war bei Abwesenheit eines Schwelbrandes kein H2 nachzuweisen (Versuche 4 - 6). Ein ähnliches Verhalten wie das von H2 konnte auch für CH4 festgestellt werden. Beispielsweise stieg der H2-Gehalt des Schwelgases im Verlauf des Versuches 1 (Anfangstemperatur 172° C) nach 1 h Luftzufuhr von 0 auf 2,16 Vol.%, während der CH4-Gehalt unter den gleichen Bedingungen von 0 auf 0,15 Vol.% anstieg. Wie die Versuche klar bestätigen, ist das Auftreten von höheren H2- und CH4-Konzentrationen im Abgas immer mit der Ausbildung eines Schwelbrandes gekoppelt. Dieses schliesst jedoch nicht vollkommen aus, dass Spuren dieser Gase im Gasvolumen oberhalb grosser Braunkohlenmengen (Bunker) ebensowohl festgestellt werden können.However, high H 2 concentrations were only found in connection with the formation of smoldering fires, whereas no H 2 was found in the absence of a smoldering fire (experiments 4 - 6). A behavior similar to that of H 2 was also found for CH 4 . For example, the H 2 content of the carbonization gas rose in the course of experiment 1 (initial temperature 172 ° C.) after 1 h of air supply from 0 to 2.16% by volume, while the CH 4 content rose from 0 to 0.15% by volume under the same conditions. As the tests clearly confirm, the occurrence of higher H 2 and CH 4 concentrations in the exhaust gas is always coupled with the formation of a smoldering fire. However, this does not completely exclude that traces of these gases in the gas volume above large quantities of lignite (bunkers) can be detected as well.

Die Ergebnisse der Versuche sind in der Fig. 1 in einem Diagramm dargestellt. Die Darstellung ist nicht maßstäblich, und zwar mit Rücksicht auf die im Verhältnis geringen Werte für Wasserstoff und Methan. Das Diagramm zeigt die Anteile der einzelnen Gaskomponenten H2' CH4' CO und C02 in Volumenprozenten (Vol.%) in Abhängigkeit von der Versuchstemperatur.The results of the tests are shown in a diagram in FIG. 1. The representation is not to scale, and in view of the relatively low values for hydrogen and methane. The diagram shows the proportions of the individual gas components H 2 ' CH 4' CO and C0 2 in volume percent (vol.%) Depending on the test temperature.

Alle Kurven zeigen einen im wesentlichen ähnlichen, glockenförmigen Verlauf mit nach oben gerichtetem Scheitelpunkt; von einer bestimmten Versuchstemperatur ab nimmt die Konzentration des jeweiligen Gases stetig zu, um nach Durchschreiten eines Maximalwertes, welcher für jedes untersuchte Gas unterschiedlich ist, wieder leicht abzufallen. Bei der Temperatur von 150° C setzte die Zündung bzw. Bildung eines Schwelbrandes ein; diese Temperatur ist durch eine vertikale, gestrichelte Linie markiert; sie wurde über ein Thermoelement ermittelt. In Abhängigkeit von den bei der Entzündung jeweils vorliegenden Bedingungen, wie Grösse des Behälters, Feuchtigkeitsgehalt des Braunkohlenstaubes und dgl. kann die Zündtemperatur auch grösser oder kleiner sein, so dass man hier von einem Temperaturbereich auszugehen hat, innerhalb dessen die Zündung einsetzt.All curves show an essentially similar, bell-shaped course with an apex pointing upwards; from a certain test temperature, the concentration of the respective gas increases steadily in order to drop slightly again after passing through a maximum value, which is different for each gas examined. At the temperature of 150 ° C the ignition or formation of a smoldering fire started; this temperature is marked by a vertical dashed line; it was determined using a thermocouple. Depending on the conditions at the time of ignition, such as the size of the container, moisture content of the lignite dust and the like, the ignition temperature can also be higher or lower, so that one has to start from a temperature range within which the ignition starts.

Bemerkenswert ist in diesem Zusammenhang in Fig. 1 zu erkennen, dass mit dem Erreichen des für die Zündung massgeblichen Temperaturbereiches die Konzentrationen von CO bzw. C02 ihren Maximalwert erreicht haben bzw. kurz davor stehen, um anschliessend wieder abzunehmen, während die Bildung der "Indikatorgase" H2 bzw. CH4 in diesem Temperaturbereich erst einsetzt und seine Maximalkonzentrationen entsprechend'später erreicht. Dabei konnte beobachtet werden, dass sich die Bildung und das Ansteigen der Konzentration von höherwertigen Kohlenwasserstoffen wie Äthan (C2H6), Propan (C3H8), Butan (C4H10), Pentan (C5H12) usw., solange diese Stoffe gasförmig vorlagen, zu höheren Temperaturbereichen hin verschob. Messungen in solchen Temperaturbereichen können beispielsweise dann von Interesse sein, wenn sich die äusseren Bedingungen, wie z. B. Druck, Feuchtigkeitsgehalt des Braunkohlenstaubes, Volumen des Behälters sowie die Atmosphäre im bzw. am Braunkohlenstaub enthaltenden Behälter geändert haben.It is noteworthy in this connection in FIG. 1 that when the temperature range relevant for the ignition is reached, the concentrations of CO or CO 2 have reached their maximum value or are about to do so, in order to subsequently decrease again, while the formation of the " Indicator gases "H 2 or CH 4 only start in this temperature range and reach their maximum concentrations accordingly later. It was observed that the formation and the increase in the concentration of higher-value hydrocarbons such as ethane (C 2 H 6 ), propane (C 3 H 8 ), butane (C 4 H 10 ), pentane (C 5 H 12 ) etc ., as long as these substances were in gaseous form, shifted to higher temperature ranges. Measurements in such temperature ranges can be of interest, for example, when the external conditions, such as e.g. B. pressure, moisture content of the lignite dust, volume of the container and the atmosphere in or on the lignite dust-containing container have changed.

Während die Gaskomponenten CO und C02 bereits bei Temperaturen unterhalb der Zündtemperatur vorliegen, treten H2 und CH4 erst bei Erreichen der Zündtemperatur auf, um verhältnismässig schnell einen Maximalwert zu erreichen und anschliessend in der Konzentration wieder abzunehmen. Der relativ stark ausgeprägte Konzentrationsanstieg der Gase H2 und CH4 ist daher besonders gut zur Früherkennung eines Schwelbrandes geeignet.While the gas components CO and C0 2 are already present at temperatures below the ignition temperature, H 2 and CH 4 only appear when the ignition temperature is reached in order to reach a maximum value relatively quickly and then decrease in concentration again. The relatively pronounced increase in the concentration of gases H 2 and CH 4 is therefore particularly well suited for the early detection of a smoldering fire.

An sich gilt zwar, dass eine Detektion desjenigen Gases am geeignetsten ist, welches die höchste Konzentration im Schwelgas aufweist. Ein Schwelbrandnachweis über die zwar in höheren Konzentrationen vorliegenden Gase CO und CO2 ist jedoch für die Praxis problematisch, da eine Grenzkonzentration festgelegt werden.muss, die, wie ausgeführt, wiederum von vielen einzelnen Einflüssen abhängt. Die "Indikatorgase" H2 und CH4 sowie höhere Kohlenwasserstoffe hingegen sind weitgehend spezifisch zur Schwelbrandidentifizierung einsetzbar. Aufgrund der höheren Konzentration an H2 im Schwelgas müsste sich dieses Gas eher eignen als CH4. Wird jedoch eine Auswahl zwischen beiden "Indikator-Gasen" nach praxisgerechter Bestimmung oder Identifikation getroffen, so bleibt nur CH4 als "Indikator-Gas" der Wahl übrig.It is true per se that the most suitable detection is the gas which has the highest concentration in the carbonization gas. However, a smoldering fire detection of the gases CO and CO 2 , which are present in higher concentrations, is problematic in practice, since a limit concentration must be defined, which, as stated, again depends on many individual influences. The "indicator gases" H 2 and CH 4 and higher hydrocarbons, on the other hand, can largely be used specifically for smoldering fire identification. Due to the higher concentration of H 2 in the carbonization gas, this gas should be more suitable than CH 4 . However, if a selection is made between the two "indicator gases" after practical determination or identification, only CH 4 remains as the "indicator gas" of choice.

In einem weiteren Versuch wurde die bis dahin labormässige Durchführung des erfindungsgemässen Verfahrens an einem mit Braunkohlenstaub gefüllten Bunker bei Vorliegen eines künstlich erzeugten Schwelbrandes erprobt. Die Anordnung ist in der Fig. 2 dargestellt.In a further experiment the previously laboratory-based implementation of the method according to the invention was tested on a bunker filled with brown coal dust in the presence of an artificially produced smoldering fire. The arrangement is shown in FIG. 2.

Ein Braunkohlenstaubbunker 1 verengt sich in seinem unteren Teil zu einem Trichter 2, der in ein Auslassorgan 3 mündet. Dieses Auslassorgan 3 besteht im einzelnen aus einem Zellenrad 4 mit Antrieb 5 und einem Faltenbalg 6 zur Anpassung an unterschiedliche Abnehmer. Weiterhin weist der Staubbunker 1 in der Höhe seines Trichters 2 eine Ringleitung 7 zur Zufuhr von Pressluft auf, damit die Schüttung im Inneren des Staubbunkers ggf. aufgelockert werden kann. Ein CH4-IR-Gasanalysator (nicht gezeigt) greift mit einer Sonde 8 in den Entleerungsstutzen des Behälters. Zusätzlich sind über die axiale Länge des Behälters drei gleichartige Sonden 9 in nahezu gleichem Abstand und ggf. in Umfangsrichtung verteilt angebracht, wobei die Sonden sowohl in den Bereich der Staubschüttung 10 als auch in den Gasraum 11 oberhalb der Schüttung hineinragen. Auch diese Sonden sind mit jeweils einem CH4-IR-Gasanalysator verbunden. Zwischen der Sonde 8 bzw. den Sonden 9 und den CH4-IR- . Gasanalysatoren sind Staubfilter (nicht gezeigt) zum Schutz der Messgeräte eingebaut.A lignite dust bunker 1 narrows in its lower part to form a funnel 2 which opens into an outlet element 3. This outlet member 3 consists in detail of a cellular wheel 4 with drive 5 and a bellows 6 for adaptation to different customers. Furthermore, the dust bunker 1 at the level of its funnel 2 has a ring line 7 for supplying compressed air, so that the bed inside the dust bunker can be loosened if necessary. A CH 4 -IR gas analyzer (not shown) reaches with a probe 8 into the emptying neck of the container. In addition, three identical probes 9 are attached at almost the same distance and possibly distributed in the circumferential direction over the axial length of the container, the probes projecting both into the area of the dust bed 10 and into the gas space 11 above the bed. These probes are also connected to a CH 4 -IR gas analyzer. Between probe 8 or probes 9 and the CH 4 -IR-. Gas analyzers are built-in dust filters (not shown) to protect the measuring devices.

Im Verlauf der einzelnen Versuche betrug der über die Sonde 9 ermittelte CH4-Grundwert im Bunker 5 - 33 ppm der über die Sonde 8 gemessene CH4-Grundwert bei der Entleerung des Bunkers ca. 10 ppm.In the course of the individual tests, the basic CH 4 value determined in probe 9 in the bunker was 5-33 ppm, the basic CH 4 value measured in probe 8 when the bunker was emptied was approximately 10 ppm.

Nach Erzeugung eines Schwelbrandes stieg der über die Sonden 9 gemessene CH4-Gehalt deutlich an. Ebenso nahm der während der Bunkerentleerung über die Sonde 8 registrierte CH4-Wert zu.After a smoldering fire had been generated, the CH 4 content measured by the probes 9 increased significantly. The CH 4 value registered during probe 8 emptying also increased.

Durch diese praxisnahen Untersuchungen wurden die zunächst labormässigen Versuche vollständig bestätigt.Through these practical investigations, the initially laboratory tests were fully confirmed.

Claims (3)

l. Verfahren zur Früherkennung von Schwelbränden in Braunkohlenstaub enthaltenden Behältern mittels Messung bestimmter aus dem Braunkohlenstaub austretender oder sich darin bildender Gase, dadurch gekennzeichnet, dass die Anwesenheit von Wasserstoff und/ oder Kohlenwasserstoffe enthaltenden Gasen im bzw. am Behälter gemessen wird.l. Method for the early detection of smoldering fires in lignite dust-containing containers by measuring certain gases escaping from or forming in the lignite dust, characterized in that the presence of hydrogen and / or hydrocarbon-containing gases in or on the container is measured. 2. Verfahren nach Anspruch l, dadurch gekennzeichnet, dass der Gehalt von Methan (CH4) und/oder höheren Kohlenwasserstoffen (CnH2n+2) gemessen wird.2. The method according to claim 1, characterized in that the content of methane (CH 4 ) and / or higher hydrocarbons (CnH 2 n + 2) is measured. 3. Vorrichtung zur Durchführung des Verfahrens nach den vorhergehenden Ansprüchen, dadurch gekennzeichnet, dass an dem Braunkohlenstaub enthaltenden Behälter ein Detektor für Wasserstoff bzw. Kohlenwasserstoffe enthaltende Gase derart angebracht ist, dass er mit einer Sonde entweder in den Entleerungsstutzen oder in den darüber befindlichen Innenraum des Behälters eingreift.3. A device for carrying out the method according to the preceding claims, characterized in that a detector for hydrogen or hydrocarbon-containing gases is attached to the container containing lignite dust in such a way that it either with a probe in the emptying nozzle or in the interior of the above Engages container.
EP82106076A 1981-07-08 1982-07-07 Method for the early detection of carbonic fires in recipients containing dust of brown coal by detection of methane Expired EP0069393B1 (en)

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AT82106076T ATE16429T1 (en) 1981-07-08 1982-07-07 PROCEDURE FOR EARLY DETECTION OF Smoldering Fires in Containers Containing Lignite Dust by Detection of Methane.

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DE3126864A DE3126864C2 (en) 1981-07-08 1981-07-08 Process for the early detection of smoldering fires in containers containing lignite dust
DE3126864 1981-07-08

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EP82902156A Pending EP0082867A1 (en) 1981-07-08 1982-07-07 Method for the early detection of fires smouldering in containers containing lignite dust by methane detection

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AT (1) ATE16429T1 (en)
AU (1) AU557814B2 (en)
CA (1) CA1187718A (en)
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DD (1) DD207438A1 (en)
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CN105510175A (en) * 2015-12-08 2016-04-20 辽宁工程技术大学 Method for measuring inhibition performance of inhibitor

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DE9417289U1 (en) * 1994-10-27 1995-01-26 Meinke Peter Prof Dr Ing Detector device, detector system and immunosensor for detecting fires
DE19808663C2 (en) * 1998-03-02 2001-05-23 Epcos Ag Fire detection system and operating procedures for this system
CN114813635B (en) * 2022-06-28 2022-10-04 华谱智能科技(天津)有限公司 Method for optimizing combustion parameters of coal stove and electronic equipment

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DE539562C (en) * 1929-01-24 1931-12-10 Hermann Heinicke Device for the determination of methane and other hydrocarbons in mixed gases by catalytic combustion
FR1321819A (en) * 1961-05-05 1963-03-22 Zd Y Prumyslove Automatisace Device for the control and analysis of gas and in particular for the detection of methane in mines and devices conforming to those fitted with the device or similar device
BE647714A (en) * 1964-05-11 1964-08-31
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CH586940A5 (en) * 1974-10-03 1977-04-15 Anglo Amer Corp South Africa New method of fire detection in mines - obtains continuous measurement of carbon dioxide concentration gives alarm when given value is exceeded
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US4129030A (en) * 1977-10-13 1978-12-12 Ads Systems, Inc. Sensing apparatus and method

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CN105510175A (en) * 2015-12-08 2016-04-20 辽宁工程技术大学 Method for measuring inhibition performance of inhibitor
CN105510175B (en) * 2015-12-08 2018-04-06 辽宁工程技术大学 A kind of method for determining retardant resistanceization performance

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DE3126864C2 (en) 1986-01-02
DD207438A1 (en) 1984-02-29
DE3267275D1 (en) 1985-12-12
ATE16429T1 (en) 1985-11-15
CA1187718A (en) 1985-05-28
CS245771B2 (en) 1986-10-16
AU8688682A (en) 1983-02-02
EP0082867A1 (en) 1983-07-06
AU557814B2 (en) 1987-01-08
DE3126864A1 (en) 1983-01-27
EP0069393B1 (en) 1985-11-06
WO1983000247A1 (en) 1983-01-20

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