JP5839915B2 - Apparatus and method for sulfur hexafluoride decomposition treatment - Google Patents

Description

  The present invention relates to a sulfur hexafluoride decomposition apparatus and method capable of easily and reliably detoxifying sulfur hexafluoride.

Sulfur hexafluoride (SF ₆ ) is a chemically non-toxic, odorless, colorless, non-flammable gas, and has been used in, for example, electrical insulation, antioxidants, liquid crystal dry etching agents, and the like.
However, in the second evaluation report (1995) of the Intergovernmental Panel on Climate Change (IPCC), as greenhouse gases (Greenhouse Gas: GHG), carbon dioxide (CO ₂ ), methane (CH ₂ ) ₄ ), nitrous oxide (N ₂ O), hydrofluorocarbon, perfluorocarbon, sulfur hexafluoride (SF ₆ ) are designated, and the reduction of greenhouse gases has become an urgent task due to recent stricter regulations.

In this greenhouse gas (GHG), in particular, the warming coefficient of sulfur hexafluoride (SF ₆ ) is 23,900 times that of carbon dioxide (CO ₂ ), and a reduction in the amount of generation is eagerly desired. . It is a stable material with a very long lifetime of 3200 years.

  Therefore, conventionally, for example, a decomposition method of waste sulfur hexafluoride by, for example, combustion decomposition, inductively coupled thermal plasma treatment, etc., using a thermal decomposition process with a heater, hydrogen and oxygen, propane, city gas, or the like has been proposed ( Patent Document 1).

JP 2001-300288 A

However, since the conventional proposed method according to Patent Document 1 thermally decomposes waste sulfur hexafluoride (SF ₆ ), harmful decomposition products (for example, SF ₄ , S ₂ F ₂ , SOF ₄ , SO ₂ F _2). , HF, F ₂ , COCl _2, etc.).

As a facility for removing these decomposition products, detoxification treatment is performed by a chemical reaction with CaO, Ca (OH) ₂ , and MgO, but the removal rate is not sufficient and is a problem.

  Further, the combustion process is a thermal decomposition process, and since the decomposition temperature is not uniform, it may be discharged without being decomposed, and there is a problem of passing through a removal facility using CaO or the like.

Furthermore, despite the fact that sulfur hexafluoride (SF ₆ ) is a harmless material, hazardous substances are generated in the treatment process, so it is necessary to pay sufficient attention to the environment, and the installation cost of the treatment equipment will increase. There's a problem.

Although it is also proposed to regenerate, as mentioned above, its use is restricted from the viewpoint of reducing greenhouse gases, and waste sulfur hexafluoride (SF ₆ ) such as storage tanks that are stored There is an urgent need to establish detoxification technology.

  In view of the above problems, an object of the present invention is to provide a sulfur hexafluoride decomposition treatment apparatus and method that can easily and reliably decompose and detoxify waste sulfur hexafluoride.

The first invention of the present invention for solving the above-described problems includes a sulfur hexafluoride storage tank for storing sulfur hexafluoride, an alkali metal melting container for storing an alkali metal melt, and the alkali metal melting container. covering the periphery of a protective container to protect the interior with an inert gas, and heating means for heating the alkali metal melt vessel from the outside of the protective container, the surface of the alkali metal melt of the alkali metal melt vessel , comprising a sulfur hexafluoride supplying means for supplying a sulfur hexafluoride (SF _6), in the alkali metal melt vessel, the alkali metal melt is reacted with sulfur hexafluoride, a metal fluoride compound And a sulfur (S) reaction product, which is a sulfur hexafluoride decomposition treatment apparatus.

  A second invention is the sulfur hexafluoride decomposition treatment apparatus according to the first invention, wherein the sulfur hexafluoride supply means is provided with a heating means.

  A third invention is the sulfur hexafluoride decomposition treatment apparatus according to the first or second invention, wherein the melting temperature of the alkali metal melt 13 is 200 to 400 ° C.

  A fourth invention is the sulfur hexafluoride decomposition treatment apparatus according to any one of the first to third inventions, wherein the alkali metal is metallic lithium (Li) or metallic sodium (Na). .

  A fifth invention is the sulfur hexafluoride decomposition apparatus according to any one of the first to fourth inventions, wherein the inert gas is argon (Ar).

A sixth invention is a sulfur hexafluoride storage tank for storing sulfur hexafluoride, into the reaction vessel, the alkali metals particle-like material, and an alkali metal supply means for supplying with an inert gas, said reaction In the container, sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ), heating means for heating when supplying the sulfur hexafluoride, and alkali metal particulates in the reaction container, It is reacted with sulfur hexafluoride (SF _6), in sulfur hexafluoride decomposition treatment apparatus characterized by comprising generating the reaction product of a metal fluoride compound and a sulfur (S).

The seventh invention comprises a sulfur hexafluoride storage tank for storing sulfur hexafluoride, a fluidized alkali metal supply means for supplying fluidized alkali metal particulates in a fluidized bed reaction vessel, and a fluidized bed reactor. , Sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ), heating means for heating when supplying the sulfur hexafluoride, and alkali metal particulates in the fluidized bed reactor, It is reacted with sulfur hexafluoride (SF _6), in sulfur hexafluoride decomposition treatment apparatus characterized by comprising generating the reaction product of a metal fluoride compound and a sulfur (S).

Advantageously, in the invention of the sixth or seventh, in sulfur hexafluoride decomposition treating apparatus, wherein the temperature pressurized heat of the sulfur hexafluoride (SF ₆₎ is 200 ° C..

A ninth aspect of the invention, together with the alkali metal is heated from the outside the molten state of the alkali metal melt vessel, injecting waste sulfur hexafluoride in the alkali metal melt, the metal fluoride compounds and sulfur (S) The sulfur hexafluoride decomposition treatment method is characterized in that the reaction product is produced to detoxify sulfur hexafluoride.

  A tenth aspect of the invention is the sulfur hexafluoride decomposition treatment method according to the ninth aspect of the invention, wherein the melting temperature of the alkali metal melt is 200 to 400 ° C.

An eleventh invention supplies the alkali metal particulates into the reactor, the sulfur hexafluoride was injected into the alkali metal particulates, to produce a reaction product of a metal fluoride compound and a sulfur (S) The sulfur hexafluoride decomposition treatment method is characterized by detoxifying sulfur hexafluoride.

A twelfth aspect of the present invention is, with flowing the alkali metal particulate in the fluidized bed reactor, the sulfur hexafluoride was injected into the alkali metal particulates, the reaction products of metal fluoride compound and sulfur (S) The sulfur hexafluoride decomposition treatment method is characterized by detoxifying sulfur hexafluoride.

According to the present invention, an alkali metal is heated from the outside to be in a molten state, and sulfur hexafluoride is injected into the alkali metal melt to produce a reaction product of metal fluoride (LiF) and sulfur (S). And sulfur hexafluoride is detoxified, so that the complete detoxification of sulfur hexafluoride (SF ₆ ) can be performed reliably and safely.

In addition, using alkali metal particles, the alkali metal particles are supplied into the space or supplied into the fluidized bed, and sulfur hexafluoride is sprayed into the metal fluoride (LiF) and sulfur (S ) And the detoxification treatment of sulfur hexafluoride, the complete detoxification treatment of sulfur hexafluoride (SF ₆ ) can be performed reliably and safely.

FIG. 1 is a schematic diagram of a sulfur hexafluoride decomposition treatment apparatus according to the first embodiment. FIG. 2 is a schematic diagram of a sulfur hexafluoride decomposition treatment apparatus according to the second embodiment. FIG. 3 is a schematic diagram of a sulfur hexafluoride decomposition treatment apparatus according to the third embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

An apparatus for decomposing sulfur hexafluoride according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a sulfur hexafluoride decomposition treatment apparatus according to the first embodiment.
As shown in FIG. 1, the sulfur hexafluoride decomposition treatment apparatus 10 </ b> A includes an SF ₆ gas storage tank 12 that is a sulfur hexafluoride storage tank for storing waste sulfur hexafluoride (SF ₆ ) 11, an alkali metal (for example, Li melting vessel 14 which is an alkali metal melting vessel for storing a metallic lithium (Li) melt (hereinafter referred to as “metallic Li melting 13”), and the periphery of said Li melting vessel 14 are covered, and the inside thereof is an inert gas. A protective container 16 that is protected by (argon, helium) 15; a first heater 17 that is a heating means for heating the inside of the Li melting container 14 from the outside of the protective container 16; and a metal Li in the Li melting container 14 An SF ₆ gas supply pipe 18 which is a sulfur hexafluoride supply means for supplying sulfur hexafluoride 11 is provided on the surface of the melt 13. The melt 13 is reacted with sulfur hexafluoride 11 to produce a reaction product 19 of metal fluoride (LiF) and sulfur (S).
In FIG. 1, symbol L ₁ indicates an SF ₆ gas supply line, L ₂ indicates an inert gas supply line, and V ₁ and V ₂ indicate open / close valves, respectively.

The melting temperature of the alkali metal melt 13 is melted using a first heater 17 provided outside so as to be 200 to 400 ° C., and the progress of the reaction is promoted, so that sulfur hexafluoride (SF ₆ ) The decomposition of 11 is complete.

Here, in this embodiment, the second heater 20 which is a heating means for heating the periphery of the SF ₆ gas supply pipe 18 is provided. However, when the reaction proceeds sufficiently, or the first heater If the metal Li melt 13 in the Li container is sufficiently heated at 17, there is no need to heat or install.

The sulfur hexafluoride (SF ₆ gas) storage tank 12 is used as the sulfur hexafluoride storage tank. After collecting the used SF ₆ gas, the liquid is applied with a predetermined pressure (for example, a pressure of 10 kg / cm ₃ or more). it may be used liquid SF ₆ storage tank for storing the SF ₆ state.

As the alkali metal used in the present invention, it is preferable to use metallic lithium (Li) from the viewpoint of operability, but it is possible to decompose sulfur hexafluoride (SF ₆ ) 11 in addition to metallic lithium, metallic sodium (Na), An alkali metal such as metal potassium (K) can be exemplified.

  The inert gas 15 is supplied to prevent sulfur hexafluoride from flowing out of the protective container 16, and argon (Ar), helium (He), or the like is used as the inert gas. Is preferred. Note that nitrogen, which is frequently used as an inert gas, is not preferable because it produces a nitride of sulfur hexafluoride.

In order to treat sulfur hexafluoride using the metal Li melt 13, first, SF ₆ gas is injected into the Li melting vessel 14 in which the metal Li is heated and melted at 200 to 400 ° C., preferably 300 to 400 ° C. Thus, the reaction of the following formula (1) is caused to occur.
Since LiF (solid) and S (solid) constituting the reaction product 19 have a high specific gravity, they accumulate at the bottom of the metal Li melt 13. If a predetermined amount is accumulated, it is discharged separately and regenerated as necessary. I am trying to process it.
6Li (solid) + SF ₆ (gas) → 6LiF (solid) + S (solid) + Q (heat of reaction) (1)

The gas phase portion in the Li melting vessel 14 is an argon gas atmosphere that is an inert gas 15. This is because in the presence of air, carbon dioxide and Li in the air react to generate lithium carbonate (Li ₂ CO ₃ ), which is not preferable.

  Further, the exhaust gas 21 is discharged to the outside after being washed with, for example, a water scrubber.

As described above, according to the present invention, the complete detoxification treatment of discarded sulfur hexafluoride (SF ₆ ) can be performed reliably and safely.

An apparatus for decomposing sulfur hexafluoride according to an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a schematic diagram of a sulfur hexafluoride decomposition treatment apparatus according to the second embodiment. In addition, about the same member as the structural member of the sulfur hexafluoride decomposition processing apparatus of Example 1 shown in FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
As shown in FIG. 2, the sulfur hexafluoride decomposition apparatus 10 </ b> B is an alkali metal in a sulfur hexafluoride storage tank 12 that stores waste sulfur hexafluoride (SF ₆ ) 11 and a reaction vessel 51. Metal lithium (Li) particulate matter (hereinafter referred to as “metal Li particulate matter”) 52 is supplied into a supply line L ₁₃ which is an alkali metal supply means for supplying the inert gas 15 and the reaction vessel 51 includes six A supply line L ₁₁ that is sulfur hexafluoride supply means for supplying sulfur fluoride (SF ₆ ) 11, a heater 55 that is heating means for supplying the sulfur hexafluoride, and the reaction vessel 51 in inner, a metal Li particulates 52, sulfur hexafluoride (SF ₆₎ 11 are reacted to those obtained by a reaction product 56 of a metal fluoride (LiF) and sulfur (S).
In FIG. 2, L ₁₁ is an SF ₆ gas supply line, L ₁₂ is an inert gas supply line, L ₁₃ is a metal Li particulate supply line, L ₁₄ is a reaction product discharge line, V ₁₂ and V _13. Is an open / close valve, a reaction product receiver, 58a is a gas supply nozzle, and 58b is a supply nozzle.

In order to treat sulfur hexafluoride using the metal Li granular material 52, first, the metal Li granular material 52 separately granulated (for example, 100 μm or less) is filled in the metal Li supply tank 53, and inert gas (Ar) is supplied. And supplied into the reaction vessel 51 from the metal Li particulate supply line L ₁₃ . At the same time, SF ₆ gas heated by a heater (200 ° C.) is injected from the gas supply nozzle 58a, thereby causing the above-described reaction (1).

Further, the reaction product 56 collected in the bottom of the reaction vessel 51 is discharged to the reaction product receiver 57 via the reaction product discharge line L _14, and so as to separately process.

Here, the reaction between the metal Li particulate 52 and the sulfur hexafluoride (SF ₆ ) 11 is an exothermic reaction as shown in the above-described formula (1), so the reaction vessel 51 is cooled as necessary. A cooling means (not shown) may be provided.

In this embodiment, as compared with the first embodiment, the waste sulfur hexafluoride (SF ₆ ) 11 can be continuously supplied and detoxified.

An apparatus for decomposing sulfur hexafluoride according to an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a schematic diagram of a sulfur hexafluoride decomposition treatment apparatus according to the third embodiment. In addition, about the same member as the structural member of the sulfur hexafluoride decomposition processing apparatus of Example 1 and 2 shown in FIG.1 and 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
As shown in FIG. 3, the sulfur hexafluoride decomposition treatment apparatus 10 </ b> C includes a sulfur hexafluoride storage tank 12 for storing waste sulfur hexafluoride (SF ₆ ) 11 and a fluidized alkali metal in a fluidized bed reactor 71. For example, fluidized metal lithium (Li) particulates 72, which are particulates, are supplied into a fluidized alkali metal supply device 73 that supplies an inert gas (for example, Ar) and a fluidized bed reactor 71, and sulfur hexafluoride ( SF ₆ ) 11 is a supply line L ₂₁ that is a sulfur hexafluoride supply means, a heater 55 that is a heating means that is heated when supplying the sulfur hexafluoride, and the fluidized bed reactor 71. The metal Li granular material 52 and sulfur hexafluoride (SF ₆ ) 11 are fluidized to produce a reaction product 56 of metal fluoride (LiF) and sulfur (S). Reference numeral 74 denotes a fluidized gas supply device that supplies a fluidized gas (for example, Ar) 75 into the fluidized bed reaction device 71.

  In this embodiment, a fluidized bed reaction device 71 is composed of a fluidized bed reaction unit 71-1, a free board unit 71-2, and a heating unit 71-3. Moreover, the free board part 73-2 has a larger flow-path cross-sectional area than the fluidized bed reaction part 73-1.

In Example 2, the metallic Li particulate matter 52 and sulfur hexafluoride SF ₆ ) 11 are supplied into the space of the reaction vessel 51 to cause contact reaction, but in this example, the fluidizing material is used. It is made to react using the fluidized bed reaction container used.

  A part of the reaction product is recovered as a recovered reaction product 76 from the fluidized bed reaction section 71-1 by the recovery device 77 after a predetermined time has elapsed. Thereafter, the fluidized material is separated, and the fluidized material is reused.

In the present embodiment, as compared with the first embodiment, the sulfur hexafluoride (SF ₆ ) 11 can be continuously supplied and detoxified.

10A, 10B Sulfur hexafluoride decomposition treatment equipment 11 Sulfur hexafluoride (SF ₆ )
12 Sulfur hexafluoride (SF ₆ gas) storage tank 13 Metal Li melt 14 Li melting vessel 15 Inert gas 16 Protective vessel 17 First heater 18 SF ₆ gas supply pipe 19 Reaction product 51 Reaction vessel 52 Metal Li Granular material 53 Metal Li supply tank 55 Heater 56 Reaction product 71 Fluidized bed reactor 72 Fluidized metal Li granular material 76 Recovery reaction product

Claims (12)

A sulfur hexafluoride storage tank for storing sulfur hexafluoride;
An alkali metal melting container for storing an alkali metal melt;
A protective container covering the periphery of the alkali metal melting container and protecting the inside with an inert gas;
Heating means for heating the inside of the alkali metal melting container from the outside of the protective container;
Comprising sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ) to the surface of the alkali metal melt in the alkali metal melting vessel,
In the alkali metal melt vessel, the alkali metal melt is reacted with sulfur hexafluoride, hexafluoride, characterized by comprising generating the reaction product of a metal fluoride compound and a sulfur (S) Sulfur decomposition treatment equipment. In claim 1,
A sulfur hexafluoride decomposition treatment apparatus, wherein the sulfur hexafluoride supply means is provided with a heating means. In claim 1 or 2,
The sulfur hexafluoride decomposition treatment apparatus, wherein a melting temperature of the alkali metal melt is 200 to 400 ° C. In any one of Claims 1 thru | or 3,
The sulfur hexafluoride decomposition treatment apparatus, wherein the alkali metal is metallic lithium (Li) or metallic sodium (Na). In any one of Claims 1 thru | or 4,
The sulfur hexafluoride decomposition treatment apparatus, wherein the inert gas is argon (Ar). A sulfur hexafluoride storage tank for storing sulfur hexafluoride;
Into the reaction vessel, the alkali metals particle-like material, and an alkali metal supply means for supplying with an inert gas,
Sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ) into the reaction vessel;
Heating means for heating when supplying the sulfur hexafluoride;
In the reaction vessel, six, wherein the alkali metal particulate is reacted with sulfur hexafluoride (SF _6), that obtained by a reaction product of a metal fluoride compound and a sulfur (S) Sulfur fluoride decomposition treatment equipment. A sulfur hexafluoride storage tank for storing sulfur hexafluoride;
Fluidized alkali metal supply means for supplying fluidized alkali metal particulates in the fluidized bed reaction vessel,
In the fluidized bed reactor, sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ),
Heating means for heating when supplying the sulfur hexafluoride;
In the fluidized bed reactor, and wherein the alkali metal particulate is reacted with sulfur hexafluoride (SF _6), that obtained by a reaction product of a metal fluoride compound and a sulfur (S) The sulfur hexafluoride decomposition treatment equipment. In claim 6 or 7,
Sulfur hexafluoride decomposition treating apparatus, wherein the temperature pressurized heat of the sulfur hexafluoride (SF ₆₎ is 200 ° C.. With the alkali metal is heated from the outside the molten state of the alkali metal melt vessel, injecting waste sulfur hexafluoride in the alkali metal melt, the reaction product of a metal fluoride compound and sulfur (S) A method for decomposing and treating sulfur hexafluoride, comprising detoxifying sulfur hexafluoride. In claim 9,
The method for decomposing sulfur hexafluoride, wherein the melting temperature of the alkali metal melt is 200 to 400 ° C. Supplies alkali metal particulates into the reactor, the sulfur hexafluoride was injected into the alkali metal particulates, to produce a reaction product of a metal fluoride compound and sulfur (S), sulfur hexafluoride A sulfur hexafluoride decomposition treatment method comprising detoxification treatment. With flowing the alkali metal particulate in the fluidized bed reactor, the sulfur hexafluoride was injected into the alkali metal particulates, to produce a reaction product of a metal fluoride compound and sulfur (S), hexafluoride A sulfur hexafluoride decomposition treatment method comprising detoxifying sulfur.

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