EP0043401B1 - Process and apparatus for removing tritium from a gaseous mixture - Google Patents

Process and apparatus for removing tritium from a gaseous mixture Download PDF

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EP0043401B1
EP0043401B1 EP81101653A EP81101653A EP0043401B1 EP 0043401 B1 EP0043401 B1 EP 0043401B1 EP 81101653 A EP81101653 A EP 81101653A EP 81101653 A EP81101653 A EP 81101653A EP 0043401 B1 EP0043401 B1 EP 0043401B1
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tritium
gaseous mixture
reaction vessel
hydrogenation
acid
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French (fr)
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EP0043401A1 (en
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Heinrich Dr. Dipl.-Chem. Weichselgartner
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Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/02—Treating gases

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  • the present invention relates to a method according to the preamble of claim 1. Furthermore, the invention relates to devices for performing such methods.
  • gaseous tritium (T,) is produced, which is known to be radioactive and must therefore be removed from the atmosphere of the work area or the like.
  • a final concentration of some 10 -5 Ci / m 3 air can be achieved in this way. In practice, however, you often have to be content with a few 10- 4 cm 3 .
  • the present invention is accordingly based on the object of specifying methods and devices with which tritium can be removed from a gas mixture more completely than was previously possible.
  • the known oxidation process in which the tritium is oxidized to water is therefore replaced by a reduction process or hydrogenation process which provides an easily separable, in particular liquid or solid, reaction product.
  • the reaction of tritium with oxygen should not fall under the terms of reduction or hydrogenation processes.
  • Suitable and proven hydrogenation reactions are the hydrogenation of carbon and petroleum or fat hardening (hydrogenation of oily fats to solid fats), the addition of hydrogen to double or triple bonds (conversion of benzene into cyclohexane, of naphthalene into decalin and tetralin), the reduction from aldehydes and ketones to alcohols and from nitriles and nitro compounds to amines.
  • the tritium can be removed from a gas mixture by hydrogenating unsaturated organic compounds, in particular unsaturated carboxylic acids.
  • unsaturated monocarboxylic acids are used with particular advantage, and the hydrogenation can advantageously be carried out catalytically.
  • Unsaturated fatty acids in particular those having 5 to 20 carbon atoms, are preferably used.
  • the linolenic acid C 17 H 29 -COOH has three double bonds: and the linoleic acid C 17 H 31 -COOH two of which: both are converted into stearic acid CH 3 - (CH 2 ) 16 -COOH during the hydrogenation. If these unsaturated monocarboxylic acids are hydrogenated with tritium, the tritium is firmly bound in the stearic acid, ie one or more of the CH 2 groups contain T instead of H.
  • the hydrogenation process can be controlled so that the tritiated stearic acid is broken down by the incorporation of the tritium into fragments with a shorter chain length and other physical properties than the long-chain C 17 fatty acids.
  • This has the great advantage that the tritium-containing reaction products can be separated continuously or discontinuously from the compounds not reacted with tritium and removed from the hydrogenation device as a result of different solubility, density or melting and boiling points. This means that a fresh reactant is always available for the hydrogenation and only relatively small amounts of tritium-containing, radioactive reaction products are formed.
  • a fixed bed, a fluidized bed, a liquid or an emulsion column can be used as the hydrogenation device or column.
  • the method and the devices according to the invention are excellently suited for exhaust air purification of work rooms and for air purification of closed systems, such as inert gas glove boxes.
  • closed systems such as inert gas glove boxes.
  • inert gas gloveboxes The advantage of inert gas gloveboxes is that the preferred unsaturated fatty acids cannot be autoxidized due to the absence of air-oxygen, so the effectiveness cannot be reduced (no high "blind consumption” of unsaturated fatty acids, no resinification, etc.).
  • the lowest T concentrations can be continuously eliminated in inert gas containers.
  • a device for carrying out the method according to the invention is shown schematically.
  • the device serves to clean the atmosphere in a closed work space 10, which is shown as a so-called glovebox.
  • the atmosphere in the closed space 10 is circulated by a fan.
  • the gas from the room 10 flows through an extraction line 14, an activity measuring device 16, a hydrogenation device 18, which is connected to a regeneration device 20, then through another activity measuring device 22 and finally through the blower 12 and a return line 24 back into the room 10.
  • the atmosphere in room 10 can consist of an inert gas, in particular an inert gas such as argon.
  • the hydrogenation device 18 can contain a fluidized bed or a fixed bed, solution or emulsion column.
  • the hydrogenation device preferably contains an unsaturated fatty acid and the regeneration device 20 serves for the separation of tritium-containing reaction products.
  • the hydrogenation device 18 may also be preceded by a known oxidizing device 26, which contains a catalytic furnace 28 and a molecular sieve column 30 and may otherwise be designed in a known manner.
  • the aim should therefore be to improve the mixing of the gas phase with the liquid phase, for example by pumping, atomizing or similar measures.

Description

Die vorliegende Erfindung betrifft ein Verfahren gemäss dem Oberbegriff des Anspruchs 1. Ferner betrifft die Erfindung Einrichtungen zur Durchführung solcher Verfahren.The present invention relates to a method according to the preamble of claim 1. Furthermore, the invention relates to devices for performing such methods.

Bei manchen kern- und plasmaphysikalischen Experimenten und Arbeiten entsteht gasförmiges Tritium (T,), das bekanntlich radioaktiv ist und daher aus der Atmosphäre des betreffenden Arbeitsraumes oder dergl. entfernt werden muss.In some nuclear and plasma-physical experiments and work, gaseous tritium (T,) is produced, which is known to be radioactive and must therefore be removed from the atmosphere of the work area or the like.

Es ist bekannt, tritiumhaltige Luft aus Arbeitsräumen, Gloveboxen und dergleichen mittels eines Gebläses abzusaugen und das Tritium in einem katalytischen Ofen, der CuO, Pd oder Pt als Katalysator enthalten kann, mit Sauerstoff zu tritiumhaltigem Wasser umzusetzen. Das entstehende Wasser wird anschliessend in einem Molekularsieb absorbiert. Die heute üblichen Tritiumabscheidungssysteme dieser Art enthalten ausser dem katalytischen Ofen und dem Molekularsieb, die die beiden Hauptkomponenten des Systems darstellen, noch Heizvorrichtungen, Kühlvorrichtungen, Wärmeaustauscher und dergleichen.It is known to extract air containing tritium from workrooms, gloveboxes and the like by means of a blower and to convert the tritium with oxygen to water containing tritium in a catalytic furnace which may contain CuO, Pd or Pt as a catalyst. The resulting water is then absorbed in a molecular sieve. The tritium deposition systems of this type which are common today contain, in addition to the catalytic furnace and the molecular sieve, which are the two main components of the system, heating devices, cooling devices, heat exchangers and the like.

Man kann auf diese Weise eine Endkonzentration von einigen 10-5Ci/m3 Luft erzielen. In der Praxis muss man sich jedoch oft mit einigen 10-4 Cilm3 begnügen.A final concentration of some 10 -5 Ci / m 3 air can be achieved in this way. In practice, however, you often have to be content with a few 10- 4 cm 3 .

Es ist noch weitgehend inklar, von welchen Faktoren die minimal zu erzielende T-Konzentration in der gereinigten Luft abhängt. Wesentlich ist vermutlich der Wasserdampfpartialdruck im Molekularsieb und die Ausbeute bei der katalytischen Oxidation. Bereits bei einer 1%-igen Beladung eines Molekularsiebs beträgt der Wasserdampfpartialdruck bei 20°C etwa 1,3 · 10-5 Pa (10-7 Torr), was bezogen auf THO einer T-Aktivität von 2 · 10-4Ci/m3 Luft entspricht. Hieraus ist sofort ein gravierender Nachteil der heute üblichen Reinigungstechnik ersichtlich: Da die Raumluft-Feuchtigkeit gleichzeitig mit dem tritiumhaltigen Wasser von den Molekularsieben absorbiert wird, ist die Grenze der optimalen Beladung der Molekularsiebe (ca. 1%) sehr schnell erreicht. Man muss daher die Molekularsiebkolonnen entsprechend gross dimensionieren oder aber häufig regenerieren, was zu grossen Mengen an kontaminiertem Wasser führt. Bei unvollständiger katalytischer Oxidation des Tritiums zu Wasser verbleibt gasförmiges Tritium, das dieMolekularsiebe ungehindert passiert und somit als unzulässige Abluftaktivität auftritt.It is still largely included on which factors the minimum T concentration in the purified air depends. The water vapor partial pressure in the molecular sieve and the yield in the catalytic oxidation are presumably essential. Even with a 1% loading of a molecular sieve, the water vapor partial pressure at 20 ° C is about 1.3 · 10 -5 Pa (10- 7 Torr), which, based on THO, has a T activity of 2 · 10 -4 Ci / m 3 corresponds to air. This immediately shows a serious disadvantage of today's cleaning technology: Since the ambient air moisture is absorbed by the molecular sieves at the same time as the water containing tritium, the optimum loading of the molecular sieves (approx. 1%) is reached very quickly. One must therefore dimension the molecular sieve columns appropriately large or frequently regenerate them, which leads to large amounts of contaminated water. In the event of incomplete catalytic oxidation of the tritium to water, gaseous tritium remains, which passes through the molecular sieves unhindered and thus occurs as an inadmissible exhaust air activity.

Man hat versucht, die oben erwähnten bekannten Verfahren durch Kühlung der Molekularsiebe mit flüssigem Stickstoff und durch neuartige Edelmetall-Katalysatoren zu beheben, die Erfolge sind jedoch nicht befriedigend.Attempts have been made to eliminate the known processes mentioned above by cooling the molecular sieves with liquid nitrogen and by means of novel noble metal catalysts, but the successes have not been satisfactory.

Der vorliegenden Erfindung liegt dementsprechend die Aufgabe zugrunde, Verfahren und Einrichtungen anzugeben, mit denen Tritium aus einem Gasgemisch vollständiger entfernt werden kann, als es bisher möglich war.The present invention is accordingly based on the object of specifying methods and devices with which tritium can be removed from a gas mixture more completely than was previously possible.

Diese Aufgabe wird erfindungsgemäss durch die Massnahmen gemäss Anspruch 1 gelöst.According to the invention, this object is achieved by the measures according to claim 1.

Gemäss der Erfindung wird also das bekannte Oxidationsverfahren, bei dem das Tritium zu Wasser oxidiert wird, durch ein Reduktionsverfahren oder Hydrierungsverfahren das ein leicht abscheidbares, insbesondere flüssiges oder festes Reaktionsprodukt liefert, ersetzt. Die Umsetzung des Tritiums mit Sauerstoff soll dabei nicht unter die Begriffe Reduktions- oder Hydrierungsverfahren fallen.According to the invention, the known oxidation process in which the tritium is oxidized to water is therefore replaced by a reduction process or hydrogenation process which provides an easily separable, in particular liquid or solid, reaction product. The reaction of tritium with oxygen should not fall under the terms of reduction or hydrogenation processes.

Wasserstoff und damit auch Tritium, insbesondere in atomarer Form, reagiert mehr oder weniger leicht mit anderen Atomen oder Molekülen, insbesondere ungesättigte Kohlenwasserstoffverbindungen. Geeignete und erprobte Hydrierungsreaktionen sind die Hydrierung von Kohlenstoff und Erdöl oder die Fetthärtung (Hydrierung öliger Fette zu festen Fetten), ferner die Anlagerung von Wasserstoff an Doppel- oder Dreifachbindungen (Umwandlung von Benzol in Cyclohexan, von Naphthalin in Dekalin und Tetralin), die Reduktion von Aldehyden und Ketonen zu Alkoholen und von Nitrilen und Nitroverbindungen zu Aminen.Hydrogen and therefore also tritium, especially in atomic form, reacts more or less easily with other atoms or molecules, especially unsaturated hydrocarbon compounds. Suitable and proven hydrogenation reactions are the hydrogenation of carbon and petroleum or fat hardening (hydrogenation of oily fats to solid fats), the addition of hydrogen to double or triple bonds (conversion of benzene into cyclohexane, of naphthalene into decalin and tetralin), the reduction from aldehydes and ketones to alcohols and from nitriles and nitro compounds to amines.

Schwere Erdölfraktionen können durch das sog. «Hydrocracking» in Produkte mit niederem Siedebereich umgewandelt werden. Das Verfahren arbeitet bei mässigen Drücken und Temperaturen in Gegenwart von Edelmetallkatalysatoren. Bei einem Einsatz von 100 Gew.-Teilen schwerem Vacuumgasöl und 3 Gew.-Teilen Wasserstoff entstehen beispielsweise nach einmaligem Durchgang

  • 3,2 Gew.-Teile NH3 + H2S
  • 2,5 Gew.-Teile C1 bis C3-Fraktionen
  • 3,6 Gew.-Teile C4-Fraktion
  • 8,7 Gew.-Teile Cs und Ce-Fraktionen
  • 14,8 Gew.-Teile C7-Fraktion

und 70,3 Gew.-Teile einer höher siedenden Fraktion.
(nach: Read, D., C.H. Watkins u. J.G. Eckhouse; Oil Gas J. 63, 86 (24.5.1965)).Heavy petroleum fractions can be converted into products with a low boiling range using so-called «hydrocracking». The process works at moderate pressures and temperatures in the presence of precious metal catalysts. If 100 parts by weight of heavy vacuum gas oil and 3 parts by weight of hydrogen are used, for example, after a single pass
  • 3.2 parts by weight of NH 3 + H 2 S
  • 2.5 parts by weight of C 1 to C 3 fractions
  • 3.6 parts by weight of C 4 fraction
  • 8.7 parts by weight of C s and C e fractions
  • 14.8 parts by weight of C 7 fraction

and 70.3 parts by weight of a higher boiling fraction.
(after: Read, D., CH Watkins and JG Eckhouse; Oil Gas J. 63, 86 (May 24, 1965)).

Es ist also grundsätzlich möglich, Hydrierungen so zu steuern, dass längerkettige Kohlenwasserstoffe in kürzerkettige überführt werden. Wie später dargelegt werden wird, stellt diese Tatsache einen besonderen Vorzug des erfindungsgemässen Verfahrens dar.It is therefore basically possible to control hydrogenations in such a way that longer-chain hydrocarbons are converted into shorter-chain ones. As will be explained later, this fact represents a particular advantage of the method according to the invention.

Es hat sich herausgestellt, dass sich das Tritium aus einem Gasgemisch durch Hydrierung von ungesättigten organischen Verbindungen, insbesondere von ungesättigten Carbonsäuren, entfernenlässt. Mit besonderem Vorteil werden ungesättigte Monocarbonsäuren verwendet, wobei die Hydrierung vorteilhafterweise katalytisch erfolgen kann. Vorzugsweise werden ungesättigte Fettsäuren, insbesondere solche mit 5 bis 20 C-Atomen verwendet.It has been found that the tritium can be removed from a gas mixture by hydrogenating unsaturated organic compounds, in particular unsaturated carboxylic acids. Unsaturated monocarboxylic acids are used with particular advantage, and the hydrogenation can advantageously be carried out catalytically. Unsaturated fatty acids, in particular those having 5 to 20 carbon atoms, are preferably used.

Beispielsweise weist die Linolensäure C17H29-COOH drei Doppelbindungen auf:

Figure imgb0001
und die Linolsäure C17H31-COOH deren zwei:
Figure imgb0002
beide gehen bei der Hydrierung in Stearinsäure CH3-(CH2)16-COOH über. Werden diese ungesättigten Monocarbonsäuren mit Tritium hydriert, so wird das Tritium fest in der Stearinsäure gebunden, d.h. eine oder mehrere der CH2-Gruppen T enthalten anstelle von H.For example, the linolenic acid C 17 H 29 -COOH has three double bonds:
Figure imgb0001
 and the linoleic acid C 17 H 31 -COOH two of which:
Figure imgb0002
 both are converted into stearic acid CH 3 - (CH 2 ) 16 -COOH during the hydrogenation. If these unsaturated monocarboxylic acids are hydrogenated with tritium, the tritium is firmly bound in the stearic acid, ie one or more of the CH 2 groups contain T instead of H.

Der Hydrierungsprozess kann so gesteuert werden, dass die tritierte Stearinsäure durch den Einbau des Tritiums in Bruchstücke mit geringerer Kettenlänge und anderen physikalischen Eigenschaften als die langkettigen C17-Fettsäuren aufgespalten wird. Dies hat den grossen Vorteil, dass die tritiumhaltigen Reaktionsprodukte infolge unterschiedlicher Löslichkeit, Dichte bzw. Schmelz-und Siedepunkten kontinuierlich oder diskontinuierlich von den nicht mit Tritium umgesetzten Verbindungen abgetrennt und aus der Hydrierungsvorrichtung entfernt werden können. Damit steht für die Hydrierung immer ein frischer Reaktionspartner zur Verfügung und es entstehen nur verhältnismässig geringe Mengen von tritiumhaltigen, radioaktiven Reaktionsprodukten.The hydrogenation process can be controlled so that the tritiated stearic acid is broken down by the incorporation of the tritium into fragments with a shorter chain length and other physical properties than the long-chain C 17 fatty acids. This has the great advantage that the tritium-containing reaction products can be separated continuously or discontinuously from the compounds not reacted with tritium and removed from the hydrogenation device as a result of different solubility, density or melting and boiling points. This means that a fresh reactant is always available for the hydrogenation and only relatively small amounts of tritium-containing, radioactive reaction products are formed.

Als Hydrierungsvorrichtung oder - kolonne können ein Festbett, ein Wirbelbett, eine Flüssigkeits- bzw. eine Emulsionskolonne verwendet werden.A fixed bed, a fluidized bed, a liquid or an emulsion column can be used as the hydrogenation device or column.

Das Verfahren und die Einrichtungen gemäss der Erfindung eignen sich hervorragend zur Abluftreinigung von Arbeitsräumen und zur Umluftreinigung von geschlossenen Systemen, wie Inertgasgloveboxen. Bei Inertgasgloveboxen ergibt sich der Vorteil, dass eine Autoxidation der vorzugsweise verwendeten ungesättigten Fettsäuren wegen der Abwesenheit von Luft-Sauerstoff nicht stattfinden kann, somit kann die Effektivität nicht verringert werden (kein hoher «Blindverbrauch» an ungesättigten Fettsäuren, keine Verharzung usw.).The method and the devices according to the invention are excellently suited for exhaust air purification of work rooms and for air purification of closed systems, such as inert gas glove boxes. The advantage of inert gas gloveboxes is that the preferred unsaturated fatty acids cannot be autoxidized due to the absence of air-oxygen, so the effectiveness cannot be reduced (no high "blind consumption" of unsaturated fatty acids, no resinification, etc.).

Wird eine Einrichtung, die nach dem erfindungsgemässen Verfahren arbeitet, als Not- bzw. Störfallsystem eingesetzt, so werden alle denkbaren Nachteile (Autoxidation, Abbau der Verbindungen) minimalisiert, da die vergleichsweise geringen Kosten für den Ersatz verbrauchter Chemikalien nicht ins Gewicht fallen.If a device that works according to the method according to the invention is used as an emergency or accident system, all conceivable disadvantages (auto-oxidation, degradation of the connections) are minimized, since the comparatively low costs for the replacement of used chemicals are negligible.

Durch die Erfindung werden die folgenden Vorteile erreicht:The following advantages are achieved by the invention:

Herkömmliche Systeme werden stets vom Wirkungsgrad der Oxidationsreaktion abhängen, nicht umgesetztes Tz-Gas verlässt die bekannten Anlagen ungehindert. Besonders in Räumen mit hoher Luftfeuchtigkeit wird die maximal zulässige Beladung der Molekularsiebe rasch überschritten. Die Restgasaktivität steigt dann rasch an.Conventional systems will always depend on the efficiency of the oxidation reaction, unreacted T z gas leaves the known plants unhindered. The maximum permissible loading of the molecular sieves is quickly exceeded, especially in rooms with high air humidity. The residual gas activity then increases rapidly.

Diese Nachteile entfallen bei dem erfindungsgemässen Verfahren. Insbesondere bei Kombination des herkömmlichen Oxidationsverfahrens mit dem erfindungsgemässen Reduktions- bzw. Hydrierungsverfahren werden sowohl tritiumhaltiges Wasser als auch T2 weitestgehend aus den gereinigten Gasgemischen beseitigt. Bei Verwendung in einem Störfallsystem hat das Verfahren gemäss der Erfindung den besonderen Vorteil, dass «Durchbruchskonzentrationen" ( > 1 % Wasserdampfkonzentration) am Molekularsieb und damit Aktivitäten über 10-5 Ci/M3 nicht auftreten können. Bei dem Verfahren gemäss der Erfindung ist ein kontinuierlicher Ersatz des verbrauchten Reaktionspartners (hydrierte Fettsäuren) und damit ein Dauereinsatz möglich, es sind keine Regenerationspausen erforderlich und die Aktivität kann daher nicht ansteigen.These disadvantages are eliminated in the method according to the invention. Particularly when the conventional oxidation process is combined with the reduction or hydrogenation process according to the invention, both tritium-containing water and T 2 are largely eliminated from the purified gas mixtures. When used in an accident system, the method according to the invention has the particular advantage that "breakthrough concentrations " (> 1% water vapor concentration) on the molecular sieve and thus activities above 10 -5 Ci / M 3 cannot occur. In the method according to the invention there is a Continuous replacement of the consumed reaction partner (hydrogenated fatty acids) and thus continuous use is possible, no breaks in regeneration are necessary and the activity cannot therefore increase.

In Inertgascontainments können geringste T-Konzentrationen kontinuierlich beseitigt werden.The lowest T concentrations can be continuously eliminated in inert gas containers.

In der Zeichnung ist beispielsweise eine Einrichtung zur Durchführung des erfindungsgemässen Verfahrens schematisch dargestellt. Die Einrichtung dient zur Reinigung der Atmosphäre in einem abgeschlossenen Arbeitsraum 10, der als sogenannte Glovebox dargestellt ist. Die Atmosphäre in dem abgeschlossenen Raum 10 wird durch ein Gebläse umgewälzt. Das Gas aus dem Raum 10 strömt durch eine Entnahmeleitung 14, ein Aktivitätsmessgerät 16, eine Hydrierungsvorrichtung 18, die mit einer Regenerationsvorrichtung 20 verbunden ist, dann durch eine weitere Aktivitätsmessvorrichtung 22 und schliesslich durch das Gebläse 12 und eine Rückführungsleitung 24 zurück in den Raum 10. Die Atmosphäre im Raum 10 kann aus einem Inertgas, insbesondere einem Edelgas wie Argon bestehen. Die Hydrierungsvorrichtung 18 kann ein Wirbelbett oder eine Festbett-, Lösungs- oder Emulsions-Kolonne enthalten. Vorzugsweise enthält die Hydrierungsvorrichtung eine ungesättigte Fettsäure und die Regenerierungsvorrichtung 20 dient zur Abscheidung von tritiumhaltigen Reaktionsprodukten.In the drawing, for example, a device for carrying out the method according to the invention is shown schematically. The device serves to clean the atmosphere in a closed work space 10, which is shown as a so-called glovebox. The atmosphere in the closed space 10 is circulated by a fan. The gas from the room 10 flows through an extraction line 14, an activity measuring device 16, a hydrogenation device 18, which is connected to a regeneration device 20, then through another activity measuring device 22 and finally through the blower 12 and a return line 24 back into the room 10. The atmosphere in room 10 can consist of an inert gas, in particular an inert gas such as argon. The hydrogenation device 18 can contain a fluidized bed or a fixed bed, solution or emulsion column. The hydrogenation device preferably contains an unsaturated fatty acid and the regeneration device 20 serves for the separation of tritium-containing reaction products.

Wenn die Atmosphäre im Raum 10 Sauerstoff enthält und z. B. aus Luft besteht, kann der Hydrierungsvorrichtung 18 noch eine bekannte Oxidierungsvorrichtung 26 vorgeschaltet sein, die einen katalytischen Ofen 28 und eine Molekularsiebkolonne 30 enthält und im übrigen in bekannter Weise ausgebildet sein kann.If the atmosphere in the room contains 10 oxygen and z. B. consists of air, the hydrogenation device 18 may also be preceded by a known oxidizing device 26, which contains a catalytic furnace 28 and a molecular sieve column 30 and may otherwise be designed in a known manner.

Die folgenden Versuchsergebnisse zeigen die Leistungsfähigkeit des erfindungsgemässen Verfahrens:

  • Die erste Versuchsanordnung bestand lediglich aus einer ständig geschüttelten Gasmaus (Vol. 150 ml), in der bei normaler Raumtemperatur 50 ml Linolsäure, 5 ml Linolensäure und 1 g eines Pd-Katalysators mit 1 ml H2 beaufschlagt wurden. so dass im freien Gasraum über der Säure-Katalysatormischung die Wasserstoff-Konzentration 1 % in Luft betrug. Die Konzentrationsabnahme wurde durch in zeitlichen Abständen durchgeführte Messungen der Wasserstoffkonzentration in µl H2 (pro ml Probe) bestimmt.
The following test results show the performance of the method according to the invention:
  • The first experimental set-up consisted only of a constantly shaken gas mouse (volume 150 ml) in which 50 ml of linoleic acid, 5 ml of linolenic acid and 1 g of a Pd catalyst were charged with 1 ml of H 2 at normal room temperature. so that the hydrogen concentration in the free gas space above the acid-catalyst mixture was 1% in air. The decrease in concentration was determined by measuring the hydrogen concentration in µl H 2 (per ml sample) at intervals.

Nach 8 Minuten ergaben sich noch 3,25 µl H2, nach 15 min noch 0,50 µl, nach 22 min noch 0,05 µl und schliesslich nach 30 min nur noch 0,002 µl H2. Wenn man die H2-Werte formal auf Tritium umrechnet, so könnte die Abnahme der Aktivität wie folgt angegeben werden:

  • Start-Aktivität 2,5 Ci, nach 8 min noch 0,8 Ci, nach 15 min noch 0,1 Ci, nach 22 min 0,01 Ci und schliesslich nach 30 min nur noch 0,001 Ci, d. h. mit dieser Anordnung würde eine Tritium-Aktivität von 2,5 Ci innerhalb von 30 Minuten auf 10-3 Ci reduziert.
After 8 minutes, 3.25 μl of H 2 were obtained , after 15 min 0.50 μl, after 22 min still 0.05 μl and finally after 30 min only 0.002 μl H 2 . If the H2 values are formally converted to tritium, the decrease in activity could be stated as follows:
  • Start activity 2.5 Ci, after 8 min 0.8 Ci, after 15 min 0.1 Ci, after 22 min 0.01 Ci and finally after 30 min only 0.001 Ci, ie with this arrangement a tritium -Activity reduced from 2.5 Ci to 10- 3 Ci within 30 minutes.

Die zweite Versuchsanordnung bestand aus einer senkrecht stehenden Edelstahl-Kolonne (0 70 mm, h = 450 mm), in der 300 ml einer Linol/ Linolensäuremischung mit Pd-Katalysator (2 g Pd auf Al2O3; 5% an Pd) über Glaskugel-Füllkörper (5 mm 0) verteilt sind. Unterhalb der Füllkörper mündet ein Gaseinleitrohr, oberhalb derselben sind Prallbleche angeordnet. Mittels einer Membranpumpe wurde ein Inertgas (He, 4 1 pro min) umgewälzt. Das freie Volumen betrug 1,5 I. Um zu vergleichbaren H2-Konzentrationen zu kommen, wurden in diese Apparatur 15 ml H2 (=37,5 Ci auf Tritium umgerechnet) eingegeben.The second experimental arrangement consisted of a vertical stainless steel column (0 70 mm, h = 450 mm) in which 300 ml of a linoleic / linolenic acid mixture with Pd catalyst (2 g Pd on Al 2 O 3 ; 5% on Pd) were transferred Glass ball packing (5 mm 0) are distributed. A gas inlet pipe opens below the filler, baffles are arranged above it. An inert gas (He, 41 per minute) was circulated using a membrane pump. The free volume was 1.5 I. In order to achieve comparable H 2 concentrations, 15 ml of H 2 ( = 37.5 Ci converted to tritium) were introduced into this apparatus.

Mit dieser Anordnung konnte eine Abnahme der (Auf der Basis der Hz-Werte errechneten) Aktivität auf 10-3 Ci erst in rund 160 min erreicht werden.With this arrangement, a decrease in the activity (calculated on the basis of the H z values) to 10- 3 Ci could only be achieved in about 160 min.

Gegenüber der ersten Versuchsanordnung ist also die fünffache Zeit aufzuwenden. Diese Tatsache ist auf die wesentlich schlechtere Durchmischung zurückzuführen. Es ist also anzustreben, beispielsweise durch Umpumpen, Zerstäuben oder ähnliche Massnahmen, die Durchmischung der Gasphase mit der Flüssigkeitsphase zu verbessern.Compared to the first test arrangement, five times the time has to be spent. This fact is due to the much poorer mixing. The aim should therefore be to improve the mixing of the gas phase with the liquid phase, for example by pumping, atomizing or similar measures.

Trotzdem zeigt ein Vergleich mit einer von der Industrie gefertigten Anlage, die nach dem bisher angewandten Prinzip (katalytische Oxidation/ Molekularsieb-Adsorption) arbeitet, welches Potential im neuen Verfahren steckt:

  • Bei gleicher H2-Startkonzentration benötigt die Industrieanlage rund 70 min um die Konzentration um einen Faktor von 10-3 zu verringern (die Laborapparatur wie beschrieben 160 min). Dabei nimmt erstere einen Raum von ca. 1,2 x 1,0 x 0,75 m ein, während die Laborapparatur lediglich 0,25 x 0,2 x 0,6 m misst und ganz wesentlich weniger kostet.
Nevertheless, a comparison with a system manufactured by industry, which works according to the principle previously used (catalytic oxidation / molecular sieve adsorption), shows the potential of the new process:
  • With the same H2 starting concentration, the industrial system needs around 70 minutes to reduce the concentration by a factor of 10- 3 (the laboratory equipment as described 160 minutes). The former occupies a space of approximately 1.2 x 1.0 x 0.75 m, while the laboratory equipment measures only 0.25 x 0.2 x 0.6 m and costs considerably less.

Eine praktische Anlage zur Prozessierung von Glovebox-Atmosphären kann z.B. die folgenden Parameter aufweisen:

  • Volumen - Glovebox ca. 1000 1
  • Gebläse-Leistung ca. 100 1/min
  • Abmessungen der Hydrierkolonne 0 12 cm h 60cm
  • Füllkörper (z. B. Al2O3) mit Pd beschichtet ca. 2 I
  • (ca. 10 g Pd pro I Flüssigkeit)
  • Füllung mit Linol/Linolensäure ca. 2 I.
A practical system for processing glovebox atmospheres can have the following parameters, for example:
  • Volume - glovebox approx. 1000 1
  • Blower output approx. 100 1 / min
  • Dimensions of the hydrogenation column 0 12 cm h 60cm
  • Packing material (e.g. Al 2 O 3 ) coated with Pd approx. 2 l
  • (approx. 10 g Pd per I liquid)
  • Filling with linoleic / linolenic acid approx. 2 I.

Claims (7)

1. Process for cleaning a gaseous mixture which contains a small proportion of tritium in which for the purpose of removing the tritium to the greatest extent possible the gaseous mixture is passed through a reaction vessel in which the tritium is absorbed by a chemical reaction and thereby removed from the gaseous mixture, characterised in that the reaction vessel through which the tritium-containing gaseous mixture flows includes an unsaturated organic compound, in particular an unsaturated carboxylic acid, to which the tritium is bound by a hydrogenation process.
2. Process as claimed in claim 1, characterised in that the gaseous mixture is passed through a reaction vessel which contains at least one polyunsaturated monocarboxylic acid, in particular li- noleic acid and/or linolenic acid.
3. Process as claimed in claim 1 or 2, characterised in that the reaction vessel additionally contains a catalyst catalysing the hydrogenation reaction.
4. Apparatus for carrying out the method as claimed in claim 1 including a reaction vessel which contains a compound which can be hydrogenated by tritium, characterised by an ar- rangementfor passing a gaseous mixture containing a small proportion of tritium through the reaction vessel which contains an unsaturated organic compound, in particular an unsaturated carboxylic acid, and a device for continuously removing compounds hydrogenated with tritium.
5. Apparatus as claimed in claim 4, characterised in that the reaction vessel includes a fluidized bed, a fixed bed column, a solution system or an emulsion system.
6. Apparatus as claimed in claim 4 or 5, characterised in that a device for catalytically oxidizing the tritium and for removing the tritium-containing water is disposed upstream of the reaction vessel.
7. Apparatus as claimed in claim 4, 5 or 6, characterised in that the device for passing the tritium-containing gaseous mixture is part of a closed gas circuit which also includes a working space (10) and a revolving device (12).
EP81101653A 1980-07-04 1981-03-06 Process and apparatus for removing tritium from a gaseous mixture Expired EP0043401B1 (en)

Applications Claiming Priority (2)

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DE3025494 1980-07-04
DE3025494A DE3025494C2 (en) 1980-07-04 1980-07-04 Process for removing tritium from a gas mixture

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EP0043401A1 EP0043401A1 (en) 1982-01-13
EP0043401B1 true EP0043401B1 (en) 1985-09-25

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EP (1) EP0043401B1 (en)
JP (1) JPS5717898A (en)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3511320C1 (en) * 1985-03-28 1986-10-09 Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V., 3400 Göttingen Device for cleaning the gas atmosphere of several work rooms
DE3606317A1 (en) * 1986-02-27 1987-09-03 Kernforschungsz Karlsruhe METHOD AND DEVICE FOR DECONTAMINATING THE EXHAUST GAS FROM THE FUEL CYCLE OF A FUSION REACTOR OF TRITIUM AND / OR DEUTERIUM IN CHEMICALLY BONDED EXHAUST GAS COMPONENTS
DE3636632A1 (en) * 1986-10-28 1988-05-05 Ntg Neue Technologien Gmbh & C ORGANIC SOLID MATERIAL FOR THE ABSORPTION OF TRITIUM (T) FROM A FLOWING GAS MIXTURE
FR2620262B1 (en) * 1987-09-09 1989-11-17 Commissariat Energie Atomique PROCESS AND PLANT FOR THE TREATMENT OF SOLID ORGANIC WASTE CONTAMINATED WITH TRITIUM
JP6044003B2 (en) 2014-07-03 2016-12-14 株式会社ピーシーエス Method for replacing tritium and removing tritium in water containing tritium
CN109887632A (en) * 2019-04-19 2019-06-14 江油联合氚碳仪器有限责任公司 System for highly humid air detritiation
CN115382389A (en) * 2022-08-23 2022-11-25 中国原子能科学研究院 Tail gas treatment method and system

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US3147243A (en) * 1960-08-08 1964-09-01 Continental Oil Co Radioactive polymers
US4178350A (en) * 1973-08-27 1979-12-11 Engelhard Minerals & Chemicals Corp. Removal of tritium and tritium-containing compounds from a gaseous stream
US4020003A (en) * 1976-02-24 1977-04-26 The United States Of America As Represented By The United States Energy Research And Development Administration Fixation of tritium in a highly stable polymer form

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JPS5717898A (en) 1982-01-29
EP0043401A1 (en) 1982-01-13
US4490288A (en) 1984-12-25
JPH0147758B2 (en) 1989-10-16
DE3025494C2 (en) 1986-01-16
CA1165096A (en) 1984-04-10
DE3172399D1 (en) 1985-10-31

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