JP2013066855A - Apparatus and method for decomposition treatment of sulfur hexafluoride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for decomposition of sulfur hexafluoride which enable convenient and reliable decomposition and detoxification of sulfur fluoride.SOLUTION: The apparatus includes a sulfur hexafluoride storage tank 12 storing sulfur hexafluoride 11, a supply tank 14 supplying a hydrolyzing agent 13 of a metal, e.g. iron, a hydrolysis section 15 packed with the hydrolyzing agent 13 to allow hydrolysis, a liquid recovery section 18 and a solid recovery section 19 recovering liquid products 16 and solid products 17, respectively, produced by the hydrolysis, a heater 20 serving as a heating means for heating the hydrolysis section 15 externally, a sulfur hexafluoride (SF) gas feed line Lfeeding sulfur hexafluoride (SF) 11 to the hydrolyzing agent 13 in the hydrolysis section 15 and a steam supply means 22 for supplying high-temperature steam 21 into the hydrolysis section 15. The sulfur hexafluoride 11 is hydrolyzed for detoxification treatment in the hydrolysis section 15.

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 degradable organisms (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 aspect of the present invention to solve the above problems, and sulfur hexafluoride storage tank for storing a sulfur hexafluoride (SF _6), wherein sulfur hexafluoride (SF ₆₎ hydrolyzing the hydrolyzing A supply tank for supplying a decomposition reaction agent, a hydrolysis reaction section filled with the hydrolysis reaction agent, sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ) into the hydrolysis reaction section, A heating means for heating the hydrolysis reaction part from the outside; a steam supply device for supplying high-temperature steam into the hydrolysis reaction part; and a liquid reaction product obtained by hydrolysis of the sulfur hexafluoride (SF ₆ ); It comprises a liquid recovery part and a solid recovery part for recovering a solid reaction product, and in the hydrolysis reaction part, sulfur hexafluoride (SF ₆ ) is hydrolyzed and detoxified. Sulfur hexafluoride decomposition A certain sense apparatus.

  According to a second aspect of the invention, there is provided the sulfur hexafluoride decomposition treatment apparatus according to the first aspect of the invention, wherein the hydrolysis reaction agent is supplied into the hydrolysis reaction section by an inert gas.

  According to a third aspect of the invention, there is provided the sulfur hexafluoride decomposition treatment apparatus according to the first or second aspect of the invention, wherein the inside of the hydrolysis reaction section is an inert gas atmosphere.

  A fourth invention is the sulfur hexafluoride decomposition treatment apparatus according to any one of the first to third inventions, wherein the temperature in the hydrolysis reaction section is 500 to 600 ° C.

  A fifth invention is the sulfur hexafluoride decomposition treatment apparatus according to any one of the first to fourth inventions, wherein the hydrolysis reaction agent is a metal or a phosphate.

According to a sixth aspect of the present invention, there is provided a sulfur hexafluoride storage tank for storing sulfur hexafluoride (SF ₆ ), a hydrolysis reaction vessel filled with a hydrolysis reaction agent therein, and a high temperature in the hydrolysis reaction section. And a steam supply means for supplying steam, wherein the sulfur hexafluoride decomposition treatment apparatus comprises a hydrolytic reaction of sulfur hexafluoride and detoxification treatment in the hydrolysis reaction vessel. .

  A seventh invention is characterized in that a hydrolysis reagent, high-temperature steam and sulfur hexafluoride are supplied into a hydrolysis reaction section, and sulfur hexafluoride is rendered harmless by hydrolysis reaction. Sulfur decomposition treatment method.

  The eighth invention is the sulfur hexafluoride decomposition treatment method according to the seventh invention, wherein the hydrolysis temperature is 500 to 600 ° C.

According to the present invention, since sulfur hexafluoride is hydrolyzed using a hydrolysis reagent, 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 graph showing the relationship between the hydrolysis reaction temperature (° C.) and the decomposition rate (%).

  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 a sulfur hexafluoride storage tank 12 for storing sulfur hexafluoride 11 as waste, and a metal hydrolysis reaction agent 13 such as iron, for example. A supply tank 14 to be supplied, a hydrolysis reaction section 15 that is filled with the hydrolysis reaction agent 13 to cause a hydrolysis reaction, and a liquid recovery section 18 that recovers a liquid reaction product 16 and a solid reaction product 17 by hydrolysis, respectively. And a solid recovery unit 19, a heater 20 as a heating means for heating the hydrolysis reaction unit 15 from the outside, and sulfur hexafluoride (SF ₆ ) in the hydrolysis reaction agent 13 in the hydrolysis reaction unit 15. 11 and sulfur hexafluoride (SF ₆₎ gas supply line L ₁ for supplying, comprising a steam supply means 22 for supplying a high-temperature steam 21 to the hydrolysis reaction unit 15, the smell in the hydrolysis section 15 , Sulfur hexafluoride 11 by hydrolysis reaction is made with detoxified.
In FIG. 1, reference numeral 23 is a reaction gas, 24 is an alkaline liquid scrubber device, 25 is an analyzer, 26 is a switching valve, L ₂ is an inert gas supply line, L ₃ is a metal Li supply line, and L ₄ is water vapor. L ₅ is a gas discharge line for the reaction gas 23, L ₆ is a gas recirculation line for the reaction gas 23, L ₇ is a gas discharge line for the reaction gas, L ₈ is a discharge line for the liquid reaction product 16, V ₁ ˜V ₆ is an open / close valve, P is a pump, and F is an exhaust fan.

Here, in the present embodiment, the hydrolysis reaction unit 15 is composed of a vertical reaction region 15a and a horizontal reaction region 15b, and the lower end side of the vertical reaction region 15a and the horizontal reaction. A fluidized bed type conveyor 27 is provided on the bottom side of the region 15b. Thus, as the reaction time elapses, the fluidized bed type conveyor 27 is driven to move the solid reaction product 17 to the solid recovery unit 19 side, and the solid reaction product 17 is dropped and recovered in the recovery container 19a. doing.
The recovered solid reaction product 17 is regenerated and reused as a hydrolysis reaction agent 13 in a known recycling process (not shown).

  The hydrolysis reaction section 15 is filled with a hydrolysis reaction agent (for example, iron) 13 in advance, and the hydrolysis reaction agent 13 is supplied from the supply tank 14 as necessary.

  In the hydrolysis reaction section 15, high-temperature steam (for example, 500 ° C.) 21 from a steam supply means (for example, a boiler) 22 is supplied into the hydrolysis reaction section 15 in order to promote the hydrolysis reaction.

In this example, iron (Fe) as a metal carrier is used as the hydrolysis reaction agent 13, but the present invention is not limited to this. For example, a metal carrier of aluminum (Al), a phosphate FePO ₄ , AlPO ₄ or the like may be used.

Here, when iron (Fe) is used as the hydrolysis reaction agent 13, the hydrolysis reaction of the following formula (1) proceeds in the hydrolysis reaction unit 15. Through the hydrolysis reaction, SF ₆ (gas) finally becomes sulfur dioxide (SO ₂ ), and further becomes sulfuric acid (H ₂ SO ₄ ).
SF ₆ (gas) + H ₂ O + Fe → H ₂ SO ₄ (liquid) + FeF ₃ (solid) (1)

FIG. 3 shows the relationship between the hydrolysis reaction temperature (° C.) and the decomposition rate (%).
The hydrolysis reaction in the hydrolysis reaction unit 15 starts at about 150 ° C., but as shown in FIG. 3, when the decomposition rate is 100%, Fe is 500 ° C. It is necessary to do it above.

Here, in FIG. 3, 5 kg of iron (Fe) and iron phosphate (FePO ₄ ) were used as the hydrolysis reaction agent 13, and the reaction gas was supplied thereto at a condition of 40 L / h. The composition of the reaction gas was sulfur hexafluoride (SF ₆ ): 10% by volume, nitrogen (N ₂ ) 80% by volume, and steam (H ₂ O): 10% by volume.
As shown in FIG. 3, when FePO ₄ was used as a reactant, it was confirmed that a decomposition rate of 100% was achieved at 450 ° C.

Therefore, the high temperature steam 21 supplied to the hydrolysis reaction unit 15 is set to 500 ° C. or higher, and the heating by the heater 20 is also controlled so that the temperature in the hydrolysis reaction unit 15 is maintained at 500 to 600 ° C. Yes.
Further, the periphery of the SF ₆ gas supply line L ₁ may be further heated by a heating means, but it is not necessary to provide it when the reaction proceeds sufficiently.

Thereby, the complete decomposition process of waste sulfur hexafluoride (SF ₆ ) can be achieved.

  Here, when supplying the hydrolysis reactant 13, for example, an inert gas 31 of argon (Ar) is supplied from an inert gas cylinder 32. As the inert gas, helium (He) or the like is preferably used in addition to argon (Ar). Nitrogen is not preferable because it produces nitrides of sulfur hexafluoride.

The gas phase portion in the hydrolysis reaction portion 15 is an argon gas atmosphere that is an inert gas. 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.

The storage tank 12 for storing waste sulfur hexafluoride (SF ₆ ) is normally stored in a gaseous state, but may be stored in a liquid state at a predetermined pressure (for example, a pressure of 10 kg / cm ₃ or more). .

Here, when storing sulfur hexafluoride (SF ₆ ) in a liquid state, for example, alcohol (for example, ethyl alcohol) can be used. This is because sulfur hexafluoride (SF ₆ ) is preferable because it has good solubility in ethyl alcohol and the OH group of the alcohol contributes to the hydrolysis reaction and promotes decomposition.

Sulfuric acid (H ₂ SO ₄ ), hydrofluoric acid (HF), and the like, which are liquid reaction products 16 generated by the hydrolysis reaction, fall from the gap of the conveyor 27 to the liquid recovery unit 18 side, and then liquid reaction products are generated. open and closing valve of the discharge line L ₈ of the object 16, is collected into the waste liquid tank 28, then the waste solution processing is performed.

The reaction gas 23 discharged from the solid recovery unit 19 side is purified by an alkaline liquid scrubber device 24 interposed in the gas discharge line L ₅ , and externally discharged from the reaction gas discharge line L ₇ by the exhaust fan F. To be released.

At this time, the presence or absence of unreacted sulfur hexafluoride (SF ₆ ) in the reaction gas 23 is confirmed by the analyzer 25 interposed in the gas discharge line L ₅ .

The analyzer 25 may be any one that confirms sulfur hexafluoride (SF ₆ ). For example, an infrared measuring device (IR meter) using infrared spectroscopy can be used.

As a result of analysis by the analyzer 25, when sulfur hexafluoride (SF ₆ ) remains in the reaction gas 23, the switching valve 26 is switched and the reaction gas 23 is supplied to the gas recirculation line L ₆ . In addition, the hydrolysis reaction is again performed in the reaction unit 15, and 100% complete decomposition treatment is performed.

In this example, iron (Fe) was used as the hydrolysis reagent 13, but metals other than iron (aluminum, manganese, zinc, calcium) and phosphates (iron phosphate, aluminum phosphate, manganese phosphate, An example of hydrolysis when zinc phosphate and calcium phosphate are used is shown in the following formulas (2) to (10).
SF ₆ (gas) + H ₂ O + Al → H ₂ SO ₄ (liquid) + AlF ₃ (solid) (2)
SF ₆ (gas) + H ₂ O + Mn → H ₂ SO ₄ (liquid) + MnF ₂ (solid) (3)
SF ₆ (gas) + H ₂ O + Zn → H ₂ SO ₄ (liquid) + ZnF ₂ (solid) (4)
SF ₆ (gas) + H ₂ O + Ca → H ₂ SO ₄ (liquid) + CaF ₂ (solid) (5)
SF ₆ (gas) + H ₂ O + FePO ₄ → H ₂ SO ₄ (liquid) + H ₂ PO ₄ (liquid) + FeF ₃ (solid) (6)
SF ₆ (gas) + H ₂ O + AlPO ₄ → H ₂ SO ₄ (liquid) + H ₂ PO ₄ (liquid) + AlF ₃ (solid) (7)
SF ₆ (gas) + H ₂ O + Mn ₃ (PO ₄ ) ₂ → H ₂ SO ₄ (liquid) + H ₂ PO ₄ (liquid) + MnF ₂ (solid) (8)
SF ₆ (gas) + H ₂ O + Zn ₃ (PO ₄ ) ₂ → H ₂ SO ₄ (liquid) + H ₂ PO ₄ (liquid) + ZnF ₂ (solid) (9)
SF ₆ (gas) + H ₂ O + Ca ₃ (PO ₄ ) ₂ → H ₂ SO ₄ (liquid) + H ₂ PO ₄ (liquid) + CaF ₂ (solid) (10)

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 treatment apparatus 10B includes a sulfur hexafluoride storage tank 12 that stores sulfur hexafluoride (SF ₆ ) 11 and a hydrolysis reaction agent 13 inside. And a steam supply means 22 for supplying the high-temperature steam 21 into the hydrolysis reactor 51. In the hydrolysis reaction section 51, sulfur hexafluoride (SF ₆ ) 11 is provided. Is hydrolyzed and detoxified.

In Example 1, the hydrolysis reactant 13 is supplied and fluidized in the reaction unit 15 and is then hydrolyzed by supplying sulfur hexafluoride (SF ₆ ) 11. In this example, A hydrolysis reaction agent 13 is filled inside, sulfur hexafluoride (SF ₆ ) 11 and high-temperature steam 21 are supplied to the filled hydrolysis reaction agent 13 from the lower side of the hydrolysis reaction vessel 51, and a heater By heating at 20 to 500 to 600 ° C., the sulfur hexafluoride (SF ₆ ) 11 is hydrolyzed.

  The liquid reaction product 16 generated by the hydrolysis is recovered by the liquid recovery unit 18 on the bottom side of the hydrolysis reactor 51 and separately subjected to waste liquid treatment.

  The reaction gas 23 is checked for the degree of decomposition by an analyzer not shown in the same manner as in Example 1, and is recycled if necessary so that the hydrolysis rate becomes 100%.

In this embodiment, the reaction is a batch-type reaction, which is preferable when waste sulfur hexafluoride (SF ₆ ) need not be continuously processed.

In addition, in the sulfur hexafluoride decomposition treatment apparatus 10B, two hydrolysis reactors 51 are provided, while one of them undergoes the hydrolysis treatment, while the other one exchanges the hydrolysis reaction agent, and alternately hexafluoride. By supplying sulfur (SF ₆ ), continuous treatment becomes possible.

As described above, according to the present invention, it is possible to completely treat sulfur hexafluoride (SF ₆ ) 100% while being a decomposition apparatus with a simple configuration. As a result, it is possible to quickly eradicate stable sulfur hexafluoride (SF ₆ ) which is 23,900 times that of carbon dioxide (CO ₂ ) and has a very long lifetime of 3200 years.

10A, 10B Sulfur hexafluoride decomposition treatment equipment 11 Sulfur hexafluoride (SF ₆ )
DESCRIPTION OF SYMBOLS 12 Sulfur hexafluoride storage tank 13 Hydrolysis reaction agent 14 Supply tank 15 Hydrolysis reaction part 16 Liquid reaction product 17 Solid reaction product 18 Liquid recovery part 19 Solid recovery part 20 Heating heater 21 High temperature steam 22 Steam supply means

Claims (8)

A sulfur hexafluoride storage tank for storing sulfur hexafluoride (SF ₆ );
A supply tank for supplying a hydrolysis reagent for hydrolyzing the sulfur hexafluoride (SF ₆ );
A hydrolysis reaction section filled with the hydrolysis reaction agent;
Sulfur hexafluoride supply means for supplying sulfur hexafluoride (SF ₆ ) into the hydrolysis reaction section;
Heating means for heating the hydrolysis reaction part from the outside;
A steam supply device for supplying high-temperature steam into the hydrolysis reaction section;
A liquid recovery unit and a solid recovery unit for recovering a liquid reaction product and a solid reaction product obtained by hydrolysis of the sulfur hexafluoride (SF ₆ );
A sulfur hexafluoride decomposition treatment apparatus, wherein sulfur hexafluoride (SF ₆ ) is hydrolyzed and detoxified in the hydrolysis reaction section. In claim 1,
A sulfur hexafluoride decomposition treatment apparatus, wherein the hydrolysis reaction agent is supplied into the hydrolysis reaction section by an inert gas. In claim 1 or 2,
An apparatus for decomposing sulfur hexafluoride, wherein the inside of the hydrolysis reaction section is an inert gas atmosphere. In any one of Claims 1 thru | or 3,
The sulfur hexafluoride decomposition treatment apparatus, wherein the temperature in the hydrolysis reaction part is 500 to 600 ° C. In any one of Claims 1 thru | or 4,
The sulfur hexafluoride decomposition treatment apparatus, wherein the hydrolysis reaction agent is a metal or a phosphate. A sulfur hexafluoride storage tank for storing sulfur hexafluoride (SF ₆ );
A hydrolysis reactor filled with a hydrolysis reagent inside,
Steam supply means for supplying high temperature steam into the hydrolysis reactor,
A sulfur hexafluoride decomposition treatment apparatus, wherein sulfur hexafluoride (SF ₆ ) is hydrolyzed and detoxified in the hydrolysis reactor. Sulfur hexafluoride, characterized by supplying hydrolysis reagent, high-temperature steam and sulfur hexafluoride into the hydrolysis reactor and detoxifying sulfur hexafluoride (SF ₆ ) by hydrolysis reaction Decomposition method. In claim 7,
The sulfur hexafluoride decomposition treatment method, wherein the hydrolysis temperature is 500 to 600 ° C.

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