EP1112222A1 - Anti-deflagration device for hydrogen recombining unit by catalysis - Google Patents

Anti-deflagration device for hydrogen recombining unit by catalysis

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Publication number
EP1112222A1
EP1112222A1 EP99936744A EP99936744A EP1112222A1 EP 1112222 A1 EP1112222 A1 EP 1112222A1 EP 99936744 A EP99936744 A EP 99936744A EP 99936744 A EP99936744 A EP 99936744A EP 1112222 A1 EP1112222 A1 EP 1112222A1
Authority
EP
European Patent Office
Prior art keywords
housing
hydrogen
outlet
filters
recombiner
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP99936744A
Other languages
German (de)
French (fr)
Inventor
Olivier Braillard
Guy Sias
Pierre Dolla
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
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Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP1112222A1 publication Critical patent/EP1112222A1/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B5/00—Water
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/075—Ethers or acetals
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/11—Aldehydes
    • A61K31/115—Formaldehyde
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/325—Carbamic acids; Thiocarbamic acids; Anhydrides or salts thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K33/00—Medicinal preparations containing inorganic active ingredients
    • A61K33/02—Ammonia; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K33/00—Medicinal preparations containing inorganic active ingredients
    • A61K33/42—Phosphorus; Compounds thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J12/00—Chemical processes in general for reacting gaseous media with gaseous media; Apparatus specially adapted therefor
    • B01J12/007—Chemical processes in general for reacting gaseous media with gaseous media; Apparatus specially adapted therefor in the presence of catalytically active bodies, e.g. porous plates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B01J19/002—Avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by suppressing side-reactions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/12—Arrangements or mounting of devices for preventing or minimising the effect of explosion ; Other safety measures
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
    • G21C19/28—Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core
    • G21C19/30—Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core with continuous purification of circulating fluent material, e.g. by extraction of fission products deterioration or corrosion products, impurities, e.g. by cold traps
    • G21C19/317—Recombination devices for radiolytic dissociation products
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/075—Ethers or acetals
    • A61K31/08—Ethers or acetals acyclic, e.g. paraformaldehyde
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/12—Ketones
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/12—Ketones
    • A61K31/121—Ketones acyclic
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/13—Amines
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/59—Compounds containing 9, 10- seco- cyclopenta[a]hydrophenanthrene ring systems
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K33/00—Medicinal preparations containing inorganic active ingredients
    • A61K33/40—Peroxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00245—Avoiding undesirable reactions or side-effects
    • B01J2219/00259—Preventing runaway of the chemical reaction
    • B01J2219/00263—Preventing explosion of the chemical mixture
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0602—Wall structures; Special features thereof
    • F17C2203/0607—Coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
    • F17C2205/03—Fluid connections, filters, valves, closure means or other attachments
    • F17C2205/0302—Fittings, valves, filters, or components in connection with the gas storage device
    • F17C2205/0341—Filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2221/00—Handled fluid, in particular type of fluid
    • F17C2221/01—Pure fluids
    • F17C2221/012—Hydrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/32—Hydrogen storage

Definitions

  • Hydrogen can be released in significant quantities under certain accidental operating circumstances of a nuclear power plant. This hydrogen accumulating in the confined atmosphere of the enclosure of the plant is capable of reaching the concentration at which the mixture it forms with air becomes explosive, which must absolutely be avoided. This is why hydrogen recombination devices have been designed, which carry out the chemical synthesis of water with it and oxygen from the ambient air and therefore maintain the hydrogen concentration at an acceptable level.
  • Their structure is simple and includes a lower gas inlet and upper outlet housing, and catalyst-lined surfaces within the housing to promote reaction.
  • the gas mixture subjected to the synthesis of water undergoes a natural draft similar to that of a chimney in the housing because of the well known exotherm of the reaction.
  • the recombiners are not without problems. Indeed, under certain conditions they can produce deflagrations; especially at the beginning of the operation of the recombiner, when the temperature rises sharply but irregularly, which produces expansions differential and deformations of the carrier plates of the catalytic coating.
  • Particles can detach from the catalytic coating, and they present their own dangers when they leave the recombiner and have entered the surrounding colder atmosphere: the water vapor which the gas current had charged while crossing the recombiner condenses, and therefore can no longer inhibit deflagrations; if the surrounding atmosphere is already heavily charged with hydrogen, the detached catalytic particles can initiate these deflagrations there, or even the explosion which the recombiners had precisely to prohibit.
  • Catalysts have also been proposed which are supposed to act for a low concentration of hydrogen so as never to allow it to rise in the enclosure; but if the hydrogen appears with an abundant flow, there is a risk of explosion.
  • the document DE 197 04 608 C describes a catalytic recombiner, the housing of which is blocked by a filter above the catalytic surfaces, and which also comprises cups for retaining the catalytic particles detached at the inlet of the housing.
  • the filters proposed here are rigid membranes or walls added to the openings small enough to retain the detached catalytic particles, with the possible exception of the smallest. This property distinguishes them from the grids commonly encountered in existing recombiners and whose sole function is to protect their content against intrusion by solid bodies, during assembly maneuvers for example and which occupy only a small proportion of the area of inlet and outlet ports. It also distinguishes them from the cups of patent DE 197 04 608 C, which are separated by spacings large enough and distributed in two layers to occupy the entire section of the housing. All these devices do not really impede the flow of gases and therefore do not prevent the gushing of a very hot plume at the outlet of the housing, nor puffs resulting from sudden recombinations on leaving or entering the housing.
  • the filters proposed here reduce these dangerous phenomena by somewhat confining the gaseous content of the housing, and thus regulating its flow. They also slow down the heating of the recombiner on the appearance of hydrogen, and therefore the thermal stresses undergone by the load-bearing surfaces of the catalytic coating and the risks of spotting of particles. On the other hand, they reduce the flow rate which can pass through the catalyst, but this counts less than the advantages mentioned, and this drawback can be corrected by increasing the size of the recombiner.
  • FIG. 1 represents a traditional recombiner
  • the recombiner of FIG. 1 comprises a flat box with rectangular faces, which is however opened by its lower face and whose front face 2 carries an upper opening 3, equipped with a protective grid 4; a similar grid could be placed through the lower opening 1.
  • a gas rich in hydrogen can thus enter through the lower opening in the housing 5; it then passes in front of plates 6 oriented vertically and transversely and whose main faces 7 carry a coating of platinum and palladium catalyzing the recombination of hydrogen.
  • Palladium produces recombination from the bass temperatures and platinum is effective at high temperatures; this is therefore essential to initiate recombination, while the role of platinum becomes preponderant as soon as the heat produced has heated the plates 6, which are very thin, having only a few tenths of a millimeter in thickness.
  • the gas heats up during the synthesis reaction of water and rises by natural convection in the housing 5 until it leaves through the upper opening 3.
  • the embodiment of the invention which is shown in FIG. 2 consisted in removing the grid 4 and putting an outlet filter 8 on at, - the upper opening 3, as well as an inlet filter 9 under the lower opening.
  • the filters 8 and 9 shown here are filters formed of intertwined metal wires, and the weft of the wires is chosen so that the interstices (from 100 to 150 ⁇ m approximately) remaining between them are finer than the catalytic particles which would be susceptible to 'be torn off during recombination: they therefore remain trapped in the housing 5 and can no longer drift towards regions rich in hydrogen which could form outside the recombiner. They continue to ensure recombination, but in a gas mixture rich in water vapor which inhibits potential deflagrations.
  • Filters 8 and 9 produce pressure drops which reduce the flow of gas passing through the recombiner and therefore, consequently, reduce the risks of deflagration which too sudden arrival of hydrogen could produce; 1 heating of the plates 6 and the risk of detachment of particles from the catalytic coating by deformations due to expansion differentials are lessened; finally, the water vapor is better retained in the recombiner. All these effects contribute to better security. Finally, the interior of the recombiner remains warmer, which improves its draft, and the plume from the recombiner is colder and therefore less reactive and less dangerous.
  • the outlet filter 8 is placed in front of the upper opening 3, rather than through it, if it is desired to reduce the pressure drop at this location. It then extends around the outlet orifice 3 to provide a more abundant outlet area for the gas, without having to enlarge the openings of the filter 8.
  • the filter 8 has the appearance of a parallelepipedal cage open in front of the outlet opening 3, and ribs 11 are used to attach it to the housing 5.
  • the inlet filter 9 is advantageously constructed in the same way, projecting around the lower opening 1 and in the form of a parallelepiped cage, in order to do not brake the air intake too much. These filters 8 and 9 projecting and encompassing empty volumes outside the housing 5 are much preferred to the usual flat filters.
  • the upper opening 3 disposed laterally can also be replaced by an upper opening 12 formed by the absence of an upper face on a recombiner housing, as illustrated in FIG. 3; in addition, this last illustrated embodiment includes a larger catalysis surface thanks to the presence of two parallel rows of plates 6, instead of one.
  • the rows can also be extended to have more plates 6; the housing, 13 in this embodiment, has then a substantially pyramidal shape (instead of being parallelepiped as in the previous embodiments) tapering between a lower portion 14 surrounding the plates 6 and an upper portion 15 at the top of which is formed the upper opening 12.
  • the lower filter 16 is still located immediately below the plates 6 and the upper filter 17 is mounted on the upper opening 12 or through it, in the same way as for FIG. 2.
  • the improvement brought by the invention is appreciable since 'During a real test, it was found that the filters reduced the threshold for the appearance of deflagrations in the recombiner from 8% of hydrogen in dry air to 10%. The heating of the plates was slower by 20%, but the local temperature differences were reduced by half.
  • the plume at the exit of the recombiner had a temperature of less than 100 ° C instead of up to 600 ° C, which should considerably reduce the risks of external deflagration; in addition, the temperature in the recombiner was 400 ° C instead of 200 ° C, favoring the effect of the draw.
  • a filter is a perforated wall or membrane, constructed to stop the detached catalyst particles but let the gases pass, while inflicting a sufficient pressure drop on the flow to slow the exit of the gas puffs. very hot.

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  • Health & Medical Sciences (AREA)
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  • Medicinal Chemistry (AREA)
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  • High Energy & Nuclear Physics (AREA)
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  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

Abstract

The invention concerns an anti-deflagration device for a hydrogen recombining unit comprising filters (8) and (9) at the input and at the output of a convection container (5) containing plates (6) coated with a catalytic coating. Said filters (8) and (9) generate a pressure drop which prevents the sudden occurrence of a large amount of gas in the recombining unit and confine inside the container (5) the particles which are released from the catalytic coating, thereby reducing the risks of deflagration.

Description

DISPOSITIF A TI-DEFLAGRATION DE RECOMBINEUR D'HYDROGÈNEHYDROGEN RECOMBINATOR TI-DEFLAGRATION DEVICE
PAR CATALYSEBY CATALYSIS
DESCRIPTIONDESCRIPTION
On décrira ici un dispositif anti- déflagration d'un recombineur d'hydrogène par catalyse.An anti-deflagration device for a hydrogen recombiner by catalysis will be described here.
De l'hydrogène peut être libéré en quantité importante dans certaines circonstances accidentelles de fonctionnement d'une centrale nucléaire. Cet hydrogène s 'accumulant dans l'atmosphère confinée de l'enceinte de la centrale est susceptible d'atteindre la concentration à laquelle le mélange qu'il forme avec l'air devient explosif, ce qui doit absolument être évité. C'est pourquoi on a conçu des appareils de recombinaison de l'hydrogène, qui réalisent la synthèse chimique de 1 ' eau avec lui et 1 ' oxygène de 1 ' air ambiant et maintiennent donc la concentration en hydrogène à un niveau acceptable. Leur structure est simple et comprend un boîtier à entrée de gaz inférieure et à sortie supérieure, et des surfaces garnies de catalyseur à l'intérieur du boîtier pour favoriser la réaction. Le mélange gazeux soumis à la synthèse de l'eau subit un tirage naturel analogue à celui d'une cheminée dans le boîtier à cause de 1 ' exothermie bien connue de la réaction. Mais les recombineurs ne sont pas sans poser des problèmes. En effet, dans certaines conditions ils peuvent produire des déflagrations ; notamment au début du fonctionnement du recombineur, quand la température s ' élève brusquement mais irrégulièrement, ce qui produit des dilatations différentielles et des déformations des plaques porteuses du revêtement catalytique.Hydrogen can be released in significant quantities under certain accidental operating circumstances of a nuclear power plant. This hydrogen accumulating in the confined atmosphere of the enclosure of the plant is capable of reaching the concentration at which the mixture it forms with air becomes explosive, which must absolutely be avoided. This is why hydrogen recombination devices have been designed, which carry out the chemical synthesis of water with it and oxygen from the ambient air and therefore maintain the hydrogen concentration at an acceptable level. Their structure is simple and includes a lower gas inlet and upper outlet housing, and catalyst-lined surfaces within the housing to promote reaction. The gas mixture subjected to the synthesis of water undergoes a natural draft similar to that of a chimney in the housing because of the well known exotherm of the reaction. But the recombiners are not without problems. Indeed, under certain conditions they can produce deflagrations; especially at the beginning of the operation of the recombiner, when the temperature rises sharply but irregularly, which produces expansions differential and deformations of the carrier plates of the catalytic coating.
Des particules peuvent se détacher du revêtement catalytique, et elles présentent des dangers propres quand elles sont sorties du recombineur et ont pénétré dans l'atmosphère environnante plus froide : la vapeur d'eau dont le courant gazeux s'était chargé en traversant le recombineur se condense, et ne peut donc plus inhiber des déflagrations ; si l'atmosphère environnante est déjà fortement chargée en hydrogène, les particules catalytiques détachées peuvent y amorcer ces déflagrations, voire l'explosion que les recombineurs devaient précisément interdire.Particles can detach from the catalytic coating, and they present their own dangers when they leave the recombiner and have entered the surrounding colder atmosphere: the water vapor which the gas current had charged while crossing the recombiner condenses, and therefore can no longer inhibit deflagrations; if the surrounding atmosphere is already heavily charged with hydrogen, the detached catalytic particles can initiate these deflagrations there, or even the explosion which the recombiners had precisely to prohibit.
Des tentatives précédentes d'améliorer le fonctionnement de recombineurs ont consisté à améliorer l'adhérence des particules catalytiques aux surfaces d'accrochage, mais les possibilités sont limitées.Previous attempts to improve the functioning of recombiners have been to improve the adhesion of catalytic particles to the attachment surfaces, but the possibilities are limited.
On a aussi proposé des catalyseurs qui sont supposés agir pour une concentration faible d'hydrogène afin de ne jamais la laisser s'élever dans l'enceinte ; mais si l'hydrogène apparaît avec un débit abondant, il y a risque d'explosion.Catalysts have also been proposed which are supposed to act for a low concentration of hydrogen so as never to allow it to rise in the enclosure; but if the hydrogen appears with an abundant flow, there is a risk of explosion.
Le document DE 197 04 608 C décrit un recombineur catalytique dont le boîtier est barré par un filtre au-dessus des surfaces catalytiques, et qui comprend encore des coupelles de rétention des particules catalytiques détachées à l'entrée du boîtier.The document DE 197 04 608 C describes a catalytic recombiner, the housing of which is blocked by a filter above the catalytic surfaces, and which also comprises cups for retaining the catalytic particles detached at the inlet of the housing.
On combat ainsi les risques de déflagration provoqués par les particules détachées du revêtement catalytique sans pourtant s'opposer à leur détachage. Cette conception n'est toutefois pas parfaite. Le filtre placé au travers du boîtier produit une perte de charge importante qui affaiblit le tirage de l'écoulement produit par le recombineur. Le texte propose de le construire avec des ouvertures pouvant aller jusqu'à 1 mm de large, mais si l'affaiblissement du tirage peut alors être réduit, le filtre ne pourra plus retenir que les plus grosses particules. Enfin, il n'est pas pris de précaution pour limiter les sorties de gaz très chauds sous forme de bouffées (la réaction de recombinaison étant explosive, et souvent saccadée en pratique) ni la température du panache émis à la sortie quand la recombinaison est faite à un débit stable.This combats the risk of explosion caused by particles detached from the catalytic coating without, however, opposing their removal. However, this design is not perfect. The filter placed through the housing produces a loss of heavy load which weakens the flow draft produced by the recombiner. The text proposes to build it with openings up to 1 mm wide, but if the weakening of the draft can then be reduced, the filter will only be able to retain the larger particles. Finally, no precaution is taken to limit the exits of very hot gases in the form of puffs (the recombination reaction being explosive, and often jerky in practice) nor the temperature of the plume emitted at the exit when the recombination is done at a stable rate.
C'est pourquoi il est préconisé ici, à titre d'invention, d'installer des filtres des deux côtés du catalyseur, et à l'entrée et à la sortie du boîtier .This is why it is recommended here, as an invention, to install filters on both sides of the catalyst, and at the inlet and outlet of the housing.
Les filtres proposés ici sont des membranes ou des parois rigides et ajoutées, aux ouvertures suffisamment petites pour retenir les particules catalytiques détachées, à l'exception peut-être des plus petites. Cette propriété les distingue des grilles couramment rencontrées dans les recombineurs existants et dont la seule fonction est de protéger leur contenu contre les intrusions de corps solides, au cours de manoeuvres de montage par exemple et qui n'occupent qu'une faible proportion de l'aire des orifices d'entrée et de sortie. Elle les distingue aussi des coupelles du brevet DE 197 04 608 C, qui sont séparées par des espacements assez grands et réparties en deux couches pour occuper toute la section du boîtier. Tous ces engins n'entravent pas véritablement l'écoulement des gaz et ne s'opposent donc pas au jaillissement d'un panache très chaud à la sortie du boîtier, ni de bouffées résultant de recombinaisons soudaines à la sortie ou à l'entrée du boîtier.The filters proposed here are rigid membranes or walls added to the openings small enough to retain the detached catalytic particles, with the possible exception of the smallest. This property distinguishes them from the grids commonly encountered in existing recombiners and whose sole function is to protect their content against intrusion by solid bodies, during assembly maneuvers for example and which occupy only a small proportion of the area of inlet and outlet ports. It also distinguishes them from the cups of patent DE 197 04 608 C, which are separated by spacings large enough and distributed in two layers to occupy the entire section of the housing. All these devices do not really impede the flow of gases and therefore do not prevent the gushing of a very hot plume at the outlet of the housing, nor puffs resulting from sudden recombinations on leaving or entering the housing.
Les filtres proposés ici réduisent ces phénomènes dangereux en confinant quelque peu le contenu gazeux du boîtier, et régularisant ainsi son écoulement. Ils ralentissent aussi 1 ' échauffement du recombineur à l'apparition de l'hydrogène, et donc les sollicitations thermiques subies par les surfaces porteuses du revêtement catalytique et les risques de détachage de particules. En contre partie, ils diminuent le débit qui peut traverser le catalyseur, mais cela compte moins que les avantages mentionnés, et on peut corriger cet inconvénient en augmentant la taille du recombineur. L'invention sera maintenant décrite plus en détail à l'aide des figures suivantes :The filters proposed here reduce these dangerous phenomena by somewhat confining the gaseous content of the housing, and thus regulating its flow. They also slow down the heating of the recombiner on the appearance of hydrogen, and therefore the thermal stresses undergone by the load-bearing surfaces of the catalytic coating and the risks of spotting of particles. On the other hand, they reduce the flow rate which can pass through the catalyst, but this counts less than the advantages mentioned, and this drawback can be corrected by increasing the size of the recombiner. The invention will now be described in more detail using the following figures:
- la figure 1 représente un recombineur traditionnel ,FIG. 1 represents a traditional recombiner,
- et les figures 2 et 3 représentent diverses formes de réalisation de l'invention.- And Figures 2 and 3 show various embodiments of the invention.
Le recombineur de la figure 1 comprend un boîtier plat aux faces rectangulaires, qui est cependant ouvert par sa face inférieure et dont la face avant 2 porte une ouverture supérieure 3, équipée d'une grille 4 de protection ; une grille semblable pourrait être placée à travers l'ouverture inférieure 1. Un gaz riche en hydrogène peut ainsi entrer par l'ouverture inférieure dans le boîtier 5 ; il passe alors devant des plaques 6 orientées verticalement et transversalement et dont les faces principales 7 portent un revêtement de platine et de palladium catalysant la recombinaison de l'hydrogène. Le palladium produit la recombinaison dès les basses températures et le platine est efficace aux températures élevées ; celui-là est donc essentiel pour amorcer la recombinaison, alors que le rôle du platine devient prépondérant dès que la chaleur produite a échauffé les plaques 6, qui sont très fines, n'ayant que quelques dixièmes de millimètres d'épaisseur. Le gaz s'échauffe au cours de la réaction de synthèse de l'eau et s'élève par convection naturelle dans le boîtier 5 jusqu'à sortir par l'ouverture supérieure 3. La réalisation de l'invention qui est représentée à la figure 2 a consisté à supprimer la grille 4 et à mettre un filtre de sortie 8 sur à, - l'ouverture supérieure 3, ainsi qu'un filtre d'entrée 9 sous l'ouverture inférieure. Les filtres 8 et 9 représentés ici sont des filtres formés de fils métalliques entrecroisés, et on choisit la trame des fils de façon que les interstices (de 100 à 150 μm environ) subsistant entre eux soient plus fins que les particules catalytiques qui seraient susceptibles d'être arrachées au cours de la recombinaison : elles restent donc prisonnières dans le boîtier 5 et ne peuvent plus dériver vers des régions riches en hydrogène qui pourraient se former hors du recombineur. Elles continuent d'assurer la recombinaison, mais dans un mélange gazeux riche en vapeur d'eau qui inhibe les déflagrations potentielles. Les filtres 8 et 9 produisent des pertes de charge qui réduisent le débit de gaz passant par le recombineur et donc, en conséquence, réduisent les risques de déflagration qu'une arrivée trop brusque d'hydrogène pourrait produire ; 1 ' échauffement des plaques 6 et les risques de détachages de particules du revêtement catalytique par des déformations dues aux dilatations différentielles sont amoindris ; enfin, la vapeur d'eau est mieux retenue dans le recombineur. Tous ces effets concourent à une meilleure sécurité. Enfin, l'intérieur du recombineur reste plus chaud, ce qui améliore son tirage, et le panache issu du recombineur est plus froid et donc moins réactif et moins dangereux.The recombiner of FIG. 1 comprises a flat box with rectangular faces, which is however opened by its lower face and whose front face 2 carries an upper opening 3, equipped with a protective grid 4; a similar grid could be placed through the lower opening 1. A gas rich in hydrogen can thus enter through the lower opening in the housing 5; it then passes in front of plates 6 oriented vertically and transversely and whose main faces 7 carry a coating of platinum and palladium catalyzing the recombination of hydrogen. Palladium produces recombination from the bass temperatures and platinum is effective at high temperatures; this is therefore essential to initiate recombination, while the role of platinum becomes preponderant as soon as the heat produced has heated the plates 6, which are very thin, having only a few tenths of a millimeter in thickness. The gas heats up during the synthesis reaction of water and rises by natural convection in the housing 5 until it leaves through the upper opening 3. The embodiment of the invention which is shown in FIG. 2 consisted in removing the grid 4 and putting an outlet filter 8 on at, - the upper opening 3, as well as an inlet filter 9 under the lower opening. The filters 8 and 9 shown here are filters formed of intertwined metal wires, and the weft of the wires is chosen so that the interstices (from 100 to 150 μm approximately) remaining between them are finer than the catalytic particles which would be susceptible to 'be torn off during recombination: they therefore remain trapped in the housing 5 and can no longer drift towards regions rich in hydrogen which could form outside the recombiner. They continue to ensure recombination, but in a gas mixture rich in water vapor which inhibits potential deflagrations. Filters 8 and 9 produce pressure drops which reduce the flow of gas passing through the recombiner and therefore, consequently, reduce the risks of deflagration which too sudden arrival of hydrogen could produce; 1 heating of the plates 6 and the risk of detachment of particles from the catalytic coating by deformations due to expansion differentials are lessened; finally, the water vapor is better retained in the recombiner. All these effects contribute to better security. Finally, the interior of the recombiner remains warmer, which improves its draft, and the plume from the recombiner is colder and therefore less reactive and less dangerous.
Divers modes de réalisation sont possibles, mais il est avantageux que le filtre de sortie 8 soit placé devant l'ouverture supérieure 3, plutôt qu'à travers elle, si on veut réduire la perte de charge à cet endroit. Il déborde alors autour de l'orifice de sortie 3 pour offrir une superficie de sortie plus abondante au gaz, sans qu'on doive agrandir les ouvertures du filtre 8. Le filtre 8 a l'aspect d'une cage parallélépipédique ouverte devant l'ouverture de sortie 3, et des nervures 11 servent à l'attacher au boîtier 5. Le filtre d'entrée 9 est avantageusement construit de la même façon, en débordant autour de 1 ' ouverture inférieure 1 et en forme de cage parallélépipédique, afin de ne pas trop freiner l'entrée d'air. Ces filtres 8 et 9 saillant et englobant des volumes vides hors du boîtier 5 sont nettement préférés aux filtres plats usuels.Various embodiments are possible, but it is advantageous that the outlet filter 8 is placed in front of the upper opening 3, rather than through it, if it is desired to reduce the pressure drop at this location. It then extends around the outlet orifice 3 to provide a more abundant outlet area for the gas, without having to enlarge the openings of the filter 8. The filter 8 has the appearance of a parallelepipedal cage open in front of the outlet opening 3, and ribs 11 are used to attach it to the housing 5. The inlet filter 9 is advantageously constructed in the same way, projecting around the lower opening 1 and in the form of a parallelepiped cage, in order to do not brake the air intake too much. These filters 8 and 9 projecting and encompassing empty volumes outside the housing 5 are much preferred to the usual flat filters.
L'ouverture supérieure 3 disposée latéralement peut aussi être remplacée par une ouverture supérieure 12 formée par l'absence d'une face supérieure sur un boîtier de recombineur, comme l'illustre la figure 3 ; de plus, cette dernière réalisation illustrée comprend une surface de catalyse plus importante grâce à la présence de deux rangées parallèles de plaques 6, au lieu d'une. Les rangées peuvent aussi être allongées pour disposer plus de plaques 6 ; le boîtier, 13 dans cette réalisation, a alors une forme sensiblement pyramidale (au lieu d'être parallélépipédique comme dans les réalisations précédentes) s' amincissant entre une portion inférieure 14 entourant les plaques 6 et une portion supérieure 15 au sommet de laquelle est ménagée l'ouverture supérieure 12. Le filtre inférieur 16 est encore situé immédiatement au-dessous des plaques 6 et le filtre supérieur 17 est monté sur l'ouverture supérieure 12 ou à travers elle, de la même façon que pour la figure 2. L'amélioration apportée par l'invention est sensible puisqu'au cours d'un essai réel, on constata que les filtres faisaient reculer le seuil d'apparition des déflagrations dans le recombineur de 8 % d'hydrogène dans de l'air sec à 10 % . L ' échauffement des plaques fut plus lent de 20 %, mais les différences locales de températures furent réduites de moitié. Le panache à la sortie du recombineur eut une température de moins de 100°C au lieu de jusqu'à 600°C, ce qui devrait réduire considérablement les risques de déflagration externe ; en outre, la température dans le recombineur fut de 400°C au lieu de 200°C, favorisant l'effet du tirage. Cette évolution considérable des températures s'explique par ce que la vapeur d'eau commence à se condenser sur le filtre de sortie, au lieu de le faire seulement dans le panache, et en ce que les particules qui pouvaient produire la recombinaison exothermique dans le panache de sortie sont toutes arrêtées. On voit aussi que la chaleur est mieux confinée dans le boîtier. Enfin, la recombinaison d'hydrogène fut réduite de 15 %, mais cette perte d'efficacité est modérée et peut être annulée si on ajoute des recombineurs ou si on agrandit les surfaces de catalyse. D'autres filtres que des réseaux de fils métalliques entrecroisés peuvent être utilisés. Au sens de l'invention, un filtre est une paroi ou membrane ajourée, construire pour arrêter les particules de catalyseur détachées mais laisser passer les gaz, tout en infligeant une perte de charge suffisante à l'écoulement pour freiner la sortie des bouffées de gaz très chauds . The upper opening 3 disposed laterally can also be replaced by an upper opening 12 formed by the absence of an upper face on a recombiner housing, as illustrated in FIG. 3; in addition, this last illustrated embodiment includes a larger catalysis surface thanks to the presence of two parallel rows of plates 6, instead of one. The rows can also be extended to have more plates 6; the housing, 13 in this embodiment, has then a substantially pyramidal shape (instead of being parallelepiped as in the previous embodiments) tapering between a lower portion 14 surrounding the plates 6 and an upper portion 15 at the top of which is formed the upper opening 12. The lower filter 16 is still located immediately below the plates 6 and the upper filter 17 is mounted on the upper opening 12 or through it, in the same way as for FIG. 2. The improvement brought by the invention is appreciable since 'During a real test, it was found that the filters reduced the threshold for the appearance of deflagrations in the recombiner from 8% of hydrogen in dry air to 10%. The heating of the plates was slower by 20%, but the local temperature differences were reduced by half. The plume at the exit of the recombiner had a temperature of less than 100 ° C instead of up to 600 ° C, which should considerably reduce the risks of external deflagration; in addition, the temperature in the recombiner was 400 ° C instead of 200 ° C, favoring the effect of the draw. This considerable evolution of temperatures is explained by the fact that the water vapor begins to condense on the outlet filter, instead of doing it only in the plume, and in that the particles which could produce the exothermic recombination in the exit plume are all stopped. We also see that the heat is better confined in the housing. Finally, the recombination of hydrogen was reduced by 15%, but this loss of efficiency is moderate and can be canceled if we add recombiners or if we increase the catalysis surfaces. Filters other than networks of crossed metallic wires can be used. Within the meaning of the invention, a filter is a perforated wall or membrane, constructed to stop the detached catalyst particles but let the gases pass, while inflicting a sufficient pressure drop on the flow to slow the exit of the gas puffs. very hot.

Claims

REVENDICATIONS
1. Dispositif anti-déflagration de recombineur d'hydrogène comprenant un boîtier (5) ouvert à une entrée inférieure (1) et une sortie supérieure (3,12) et garni de surfaces (16) porteuses de revêtement catalytique de la synthèse de l'eau, caractérisé en ce que l'entrée et la sortie sont garnies de filtres (8,9,16,17) fixes de rétention des particules catalytiques.1. Anti-deflagration device for a hydrogen recombiner comprising a casing (5) open to a lower inlet (1) and an upper outlet (3.12) and provided with surfaces (16) carrying the catalytic coating of the synthesis of l water, characterized in that the inlet and outlet are fitted with fixed filters (8, 9, 16, 17) for retaining the catalytic particles.
2. Dispositif selon la revendication 1, caractérisé en ce que le filtre à la sortie du boîtier est placé hors du boîtier et déborde autour de l'orifice de sortie. 2. Device according to claim 1, characterized in that the filter at the outlet of the housing is placed outside the housing and projects around the outlet orifice.
3. Dispositif selon l'une quelconque des revendications 1 ou 2 , caractérisé en ce que les filtres sont formés de fils métalliques entrecroisés.3. Device according to any one of claims 1 or 2, characterized in that the filters are formed of crossed metallic wires.
4. Dispositif selon l'une quelconque des revendications 1 à 3 , caractérisé en ce que le boîtier (5) est un parallélépipède et la sortie (3) est latérale .4. Device according to any one of claims 1 to 3, characterized in that the housing (5) is a parallelepiped and the outlet (3) is lateral.
5. Dispositif selon l'une quelconque des revendications 1 à 3 , caractérisé en ce que le boîtier (13) est pyramidal. 5. Device according to any one of claims 1 to 3, characterized in that the housing (13) is pyramidal.
EP99936744A 1998-08-17 1999-08-17 Anti-deflagration device for hydrogen recombining unit by catalysis Withdrawn EP1112222A1 (en)

Applications Claiming Priority (3)

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FR9810468 1998-08-17
FR9810468A FR2782278B1 (en) 1998-08-17 1998-08-17 CATALYSIS HYDROGEN RECOMBINATOR ANTI-DEFLAGRATION DEVICE
PCT/FR1999/001999 WO2000009442A1 (en) 1998-08-17 1999-08-17 Anti-deflagration device for hydrogen recombining unit by catalysis

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CA (1) CA2340034A1 (en)
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US8568395B2 (en) 2004-05-03 2013-10-29 Woodwelding Ag Light diffuser and process for producing the same
CN105334305B (en) * 2014-07-14 2020-10-16 霍尼韦尔国际公司 Porous member
FR3025857B1 (en) * 2014-09-11 2017-04-21 Air Liquide HYDROGEN SUPPLY STATION
EP3023992A1 (en) * 2014-11-21 2016-05-25 Westinghouse Electric Germany GmbH Filtered containment vent system for a nuclear power plant

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DE4003833A1 (en) * 1990-01-08 1991-07-11 Grs Ges Fuer Reaktorsicherheit Catalytic hydrogen gas absorption unit for nuclear reactors - has filter enclosure to protect catalytic coating from aerosol fat and steam pollution before working temp. is reached
DE4036126A1 (en) * 1990-11-13 1992-05-14 Grs Ges Reaktorsicherheit Hydrogen oxidn. catalyst container - with aerosol-impermeable wall, useful in light water reactor
DE19704608C1 (en) * 1997-02-07 1998-06-10 Siemens Ag Convection-driven hydrogen recombination chimney within nuclear power plant containment

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AU5173499A (en) 2000-03-06
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CA2340034A1 (en) 2000-02-24
FR2782278A1 (en) 2000-02-18

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