JP2001054723A - Method and apparatus for decomposing halogenated hydrocarbon gas - Google Patents

Abstract

(57) [Summary] Halogenation capable of decomposing halogenated hydrocarbon gas economically and stably without the need for special treatment and without generating dioxins without being capable of large-scale treatment Provided are a method and an apparatus for decomposing a hydrocarbon gas. SOLUTION: In treating a gas containing a halogenated hydrocarbon gas to decompose the halogenated hydrocarbon gas, a halogen-containing gas-resistant and conductive carrier 3 carries a halogenated hydrocarbon gas decomposition catalyst 4. Then, while the carrier 3 is heated by the electromagnetic induction heating mechanisms 5 and 6, a gas containing a halogenated hydrocarbon gas is passed through the carrier 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for decomposing a halogenated hydrocarbon gas, and more particularly to a method and an apparatus for efficiently decomposing ozone-depleting substances such as specific fluorocarbons into harmless substances.

[0002]

2. Description of the Related Art Halogenated hydrocarbons include organic chlorinated solvents and fluorocarbons, which are generally chemically and thermally stable, oil-soluble and highly volatile. Utilizing this property, for example, organochlorine solvents are used in large quantities in various industrial fields, such as dry cleaning detergents and metal degreasing detergents, and chlorofluorocarbons are used as cooler refrigerants and resin foaming agents. However, when released into the environment, they cause serious environmental problems such as destruction of the ozone layer and global warming, and substances that are carcinogenic and teratogenic when ingested by the human body have been pointed out. ing.

[0003] As a countermeasure to avoid these, various decomposition processing techniques have been proposed. For example, Japanese Patent Application Laid-Open No. H10-180040 discloses a method in which hydrogen, methane, and the like are mixed with chlorofluorocarbon gas for combustion decomposition. In this technique, chlorofluorocarbon and a combustion aid such as methane and hydrogen are added to the inside of a cylindrical burner to improve the combustibility, and mixing is performed by swirling flow to achieve uniform combustion (combustion method).

[0004] Japanese Patent Application Laid-Open No. 9-276691 discloses a method of hydrolyzing chlorofluorocarbon in a high-frequency plasma decomposition furnace, and introducing and burning the carbon dioxide and hydrogen generated by introducing air (plasma). Decomposition method).

Further, Japanese Patent Application Laid-Open No. Hei 10-180040 discloses a method for efficiently performing a photolysis treatment by passing a gas containing an organochlorine compound through a plurality of ultraviolet irradiation reactors in which gas is mixed completely and incompletely. It is disclosed (ultraviolet ray decomposition method).

Further, JP-A-8-38853 discloses a method of decomposing a halogen-containing waste by a hydrolysis reaction and an oxidative decomposition reaction with an oxygen-containing fluid in the presence of supercritical water at a high temperature and a high pressure. It has been disclosed (supercritical water splitting method).

Furthermore, Japanese Patent Application Laid-Open No. 6-343827 discloses a method in which a Freon-containing gas is brought into contact with a catalyst comprising platinum-supported silicon carbide for efficient decomposition. According to this technique, by using platinum-supported silicon carbide as a catalyst, corrosion resistance against hydrogen chloride generated during decomposition of chlorofluorocarbon is improved, and stable catalytic activity can be maintained for a long time.

[0008]

SUMMARY OF THE INVENTION Among the above prior arts,
Combustion method, plasma decomposition method, UV decomposition method and supercritical water decomposition method have a certain effect on the decomposition treatment of halogenated hydrocarbons, but efficiently and safely detoxify halogenated hydrocarbon gas in large quantities. As a method, it is hard to say that all are sufficient methods. For example, in the combustion method, a high temperature of 700 ° C. or more is required, and in addition, the released halogen forms a highly corrosive gas (hydrogen fluoride, hydrogen chloride, etc.), and the combustion furnace is corroded. Have a problem,
Also, it is difficult to control the temperature of combustion. In the plasma decomposition method, the running cost for electric power, plasma gas, and the like is high, and there is a problem in economy. Further, in the ultraviolet decomposition method, there is a limit to the scale-up of an ultraviolet lamp or a quartz jacket, and it is not suitable for decomposition of a large amount of gas. Further, the supercritical water splitting method requires a temperature of 400 ° C. or higher and a high pressure of 320 atm or higher.

[0009] In contrast to these techniques, the catalytic decomposition method has an advantage that an efficient treatment can be performed at a relatively low temperature and the treatment apparatus is simple. However, since the catalyst used in this catalytic decomposition method is generally expensive, if the catalyst is deteriorated due to uneven heating of the catalyst by an externally heated electric heater, the frequency of replacing the catalyst increases, and the economical efficiency increases. Will decrease. When a metal is used as the catalyst carrier,
There is a possibility that the catalyst carrier may be deteriorated by a halogen-containing gas such as a hydrogen halide gas.

Further, when the inventors of the present invention analyzed in detail the cracked gas generated when the catalyst was cracked using an externally heated electric heater as a heating source, it was found that the cracked gas contained dioxin. Was confirmed.

The present invention has been made in view of the above circumstances and is capable of mass processing, economically and stably producing halogenated hydrocarbons without special treatment and without generating dioxins. An object of the present invention is to provide a method and an apparatus for decomposing a halogenated hydrocarbon gas, which can decompose the gas.

[0012]

According to a first aspect of the present invention, there is provided a method for treating a gas containing a halogenated hydrocarbon gas to decompose the halogenated hydrocarbon gas, comprising the steps of: A gaseous and conductive carrier is loaded with a halogenated hydrocarbon gas decomposition catalyst, and the carrier is passed through a gas containing a halogenated hydrocarbon gas while heating the carrier by electromagnetic induction heating. And a method for decomposing a halogenated hydrocarbon gas.

In a second aspect based on the first aspect, the carrier is at least one of SiC and stainless steel.
Provided is a method for decomposing a halogenated hydrocarbon gas, wherein the method is constituted by a seed.

A third invention is characterized in that, in the first invention or the second invention, the catalyst contains at least one element selected from the group consisting of Pt, Pd, Au, Rh and Ni. The present invention provides a method for decomposing halogenated hydrocarbon gas.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the catalyst comprises W, Cr, Fe, Mo.
And a method for decomposing a halogenated hydrocarbon gas, comprising at least one element selected from the group consisting of V and V.

In a fifth aspect based on the first or second aspect, the catalyst is at least one element selected from the group consisting of Pt, Pd, Au, Rh and Ni, and / or W , Cr, Fe, Mo and V, at least one element selected from the group consisting of:
A method for decomposing a halogenated hydrocarbon gas, characterized by containing titania (TiO ₂ ).

A sixth aspect of the present invention is a method for treating a gas containing a halogenated hydrocarbon gas to decompose the halogenated hydrocarbon gas, wherein the halogen-containing gas-resistant conductive body is heated by electromagnetic induction heating. A method for decomposing a halogenated hydrocarbon gas, wherein a gas containing a halogenated hydrocarbon gas is passed through the heating body while heating in a heating method.

A seventh invention provides the method for decomposing a halogenated hydrocarbon gas according to the sixth invention, wherein the heating element is made of at least one material of SiC and stainless steel. I do.

According to an eighth aspect of the present invention, there is provided a halogen-resistant gas-conductive carrier which carries a halogenated hydrocarbon gas cracking catalyst and through which a gas containing a halogenated hydrocarbon gas is passed. Provided is a halogenated hydrocarbon gas decomposition apparatus, comprising: a heating mechanism for heating by an induction heating method.

According to a ninth aspect of the present invention, there is provided a halogen-containing gas-resistant and conductive heater through which a gas containing a halogenated hydrocarbon gas passes, and a heating mechanism for heating the heater by an electromagnetic induction heating method. The present invention provides an apparatus for decomposing a halogenated hydrocarbon gas, comprising:

The inventors of the present invention have found that dioxin is generated by the conventional catalytic decomposition method because, in an externally heated electric heater used as a heating means, the decomposition gas is difficult to cool due to its radiant heat, and dioxin is generated. It is presumed that this is because the temperature is kept in the re-synthesizing temperature range, and in order to prevent such a situation, it has been conceived that an electromagnetic induction heating system capable of rapid heating and rapid cooling may be used. In other words, since the electromagnetic induction heating method enables rapid heating and rapid cooling in this way, it can pass through the resynthesis temperature region of dioxin in a short time, and can prevent resynthesis of dioxins. In addition, when the electromagnetic induction heating method is used, uniform heating is possible, so that catalyst deterioration due to uneven heating is unlikely to occur. further,
By using a halogen-containing gas-resistant catalyst carrier, it is possible to perform a pollution-free treatment for stably decomposing a halogenated hydrocarbon gas for a long time. Furthermore, since only electromagnetic induction heating is performed without using such special treatment, a large amount of treatment is possible, and it is economical.

Further, since the halogenated hydrocarbon gas can be oxidized and decomposed by combustion without using a catalyst, as in the sixth and ninth inventions, instead of the carrier of the catalyst, the heated gas through which the gas passes is used. The same effect as in the case of using a catalyst can be obtained by providing a body and heating the heated body by electromagnetic induction to burn and oxidize and decompose the halogenated hydrocarbon gas.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. FIG. 1 is a cross-sectional view showing an example of an apparatus for decomposing a halogenated hydrocarbon gas used for carrying out the present invention. The decomposition apparatus 1 includes an insulating cylindrical container 2 and a carrier 3 provided in the cylindrical container 2 and supporting a decomposition catalyst 4.
And an electromagnetic induction coil 5 wound around the outside of the cylindrical container 2
And a high frequency power supply 6 for supplying high frequency to the electromagnetic induction coil 5
And

In the cylindrical container 2, a gas containing a halogenated hydrocarbon gas such as chlorofluorocarbon is introduced from one opening 2a, and decomposed gas is discharged from the other opening 2b.

The carrier 3 of the cracking catalyst 4 is made of a conductive material having resistance to a halogenated hydrocarbon gas and a halogen-containing gas generated by its decomposition, that is, excellent corrosion resistance in a halogen-containing gas atmosphere. Have been. The carrier 3 is made conductive because the carrier 3 is heated by Joule heat of the eddy current generated by the electromagnetic induction coil 5. Examples of such a material of the carrier 3 include carbon ceramics such as SiC, stainless steel (SUS), and the like. Further, by making the carrier 3 into a honeycomb shape or a similar shape, the contact efficiency between the catalyst and the halogenated hydrocarbon is improved, and it is possible to solve the problem of gas drift and the like.

As the decomposition catalyst 4, hydrogen halide is used.
Pt, Pd, Au, Rh and Ni with high corrosion resistance
Containing at least one element (group 1 element)
And among W, Cr, Fe, Mo and V
Those containing at least one element (Group 2 element) are preferably used
Can be. Further, the first group element or the second group element
Elements and TiO₂More preferably, the first group
Element, second group element and TiO₂Especially those containing all
Preferred. Group 1 element, Group 2 element and TiO ₂And all
Decomposes halogenated hydrocarbon gas
In addition to the function, it also has a function to decompose hydrocarbon gas,
High performance.

The first group element and the second group element may be a single substance or a compound, but the first group element is preferably used alone, and the second group element is an oxide, a carbide, a nitride, a sulfide. It is preferable to use it in a compound state. Among the first group elements, Pt is particularly preferred. Further, as the compound of the second group element, WO ₃ , CrO ₃ , Fe
Oxides such as ₂ O ₃ , MoO ₃ , and V ₂ O ₅ are suitable,
Of these, WO ₃ is particularly preferred. The combination of Pt—WO ₃ —TiO ₂ belonging to the group containing all of the first group element, the second group element, and TiO ₂ is most preferable because it exhibits high halogenated hydrocarbon decomposition performance even at a low temperature.

Examples of substances that can be treated in the present invention include Freon 11 (CFCl ₃ ) and Freon 12 (CF ₂
Various fluorocarbons represented by Cl ₂ ) can be exemplified. In addition, by appropriately setting the operating conditions, it is effective not only for decomposing various halogenated hydrocarbon gases such as volatile organic compounds (VOC's) such as tetrachloroethylene, but also gases containing dioxins, as well as fluorocarbons. It is.

In order to decompose the halogenated hydrocarbon gas by such a decomposer 1, first, power is supplied to the electromagnetic induction coil 5 from the high-frequency power source 6 to generate an eddy current in the carrier 3, and the joule The carrier 3 is heated to the operating temperature of the decomposition catalyst 4 by performing electromagnetic induction heating that generates heat. In this state, a gas containing a halogenated hydrocarbon gas as described above is introduced from the side of the opening 2 a of the cylindrical container 2 and passed through the carrier 3.

The gas containing the halogenated hydrocarbon gas is subjected to the exothermic action of the heated carrier 3 and the action of the decomposition catalyst while passing through the carrier 3, and the halogenated hydrocarbon gas therein is converted to, for example, HCl, HF, is decomposed like CO _2. The decomposed gas is supplied to the opening 2b of the cylindrical container 2.
Is discharged from

The preferred decomposition temperature for decomposing the halogenated hydrocarbon gas as described above is 200 to 800 ° C.
And more preferably 300 to 500 ° C. This is because the catalyst performance does not appear at lower temperatures, and at higher temperatures, the life of the catalyst is reduced, and furthermore, it is considered that the corrosion of the reactor by the acid gas becomes severe.

As described above, since the heating is performed by the electromagnetic induction heating method, the dioxin can be passed through the resynthesis temperature region in a short time, the resynthesis of dioxins can be prevented, and the catalyst is deteriorated due to uneven heating. Is unlikely to occur. Further, since the carrier 3 has a halogen-containing gas resistance, it is possible to perform a pollution-free treatment for stably decomposing the halogenated hydrocarbon gas for a long time.

In the above-described apparatus, the halogenated hydrocarbon is decomposed by the exothermic action of the carrier 3 and the action of the decomposition catalyst 4. However, the carrier 3 is simply used as a heating element without using a decomposition catalyst, and the exothermic action is used. Halogenated hydrocarbons can also be oxidatively decomposed by combustion. As described above, in the combustion oxidative decomposition of halogenated hydrocarbons performed using the high-temperature heat generation of the electromagnetic induction heater without using a catalyst, a higher decomposition temperature is required. ~ 12
00 ° C.

[0034]

(Example 1) Using a small flow reactor having the structure shown in FIG. 1, decomposition of Freon 12 (CF ₂ Cl ₂ ) was performed. Platinum (Pt) was used as the decomposition catalyst, and the diameter was 2
cm and a length of 4 cm on a porous SiC honeycomb (manufactured by IBIDEN). Air was introduced for the oxidative decomposition of chlorofluorocarbons, and steam was introduced for suppressing the decrease in the activity of the catalyst. The decomposition conditions are as follows. Decomposition temperature 500 ° C Freon concentration 1.5% by volume Gas flow rate 1500cc / hr Electromagnetic induction frequency 100kHz

Table 1 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 1, the decomposition rate was as high as 99.0%, and the activity was hardly reduced even after 200 hours. Further, the concentration of dioxin in the exhaust gas was a low value of 0.1 ng-TEQ / Nm ³ or less.

(Embodiment 2) Freon 12 in Embodiment 1
In the decomposition of, an experiment was carried out by changing the supported catalyst to metal oxide (WO ₃ ). The decomposition conditions such as the shape and size of the honeycomb, decomposition temperature, Freon concentration, gas (air / water vapor) inflow, and inverter frequency (electromagnetic induction frequency) were set to be the same as those in Example 1.

Table 1 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 1, the CFC decomposition rate was as high as about 93%, though not as high as that of Example 1 (supporting a Pt catalyst). A continuous experiment was performed for about 200 hours in the same manner as in Example 1. However, the decomposition rate was almost constant, and almost no decrease in the activity of the catalyst was observed.
Also, the dioxin concentration in the exhaust gas was 0.1%.
ng-TEQ / Nm ³ or less.

Example 3 Using a small flow reactor having the structure shown in FIG. 1, a combustion oxidative decomposition experiment of chlorofluorocarbon using the high-temperature heat generation of a SiC honeycomb was conducted. At this time, SiC
A honeycomb having the same shape and size as in Example 1 was used, and methane gas was added as a combustion aid in addition to the air of the carrier. In addition, the operating temperature was set to a high temperature to improve the efficiency of decomposing fluorocarbons and suppress the synthesis of dioxins. The decomposition conditions are as follows. Decomposition temperature 800 ° C Freon concentration 1.5% by volume Methane concentration 1.0% by volume Gas flow rate 1500cc / hr

Table 1 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 1, the decomposition rate of chlorofluorocarbon was about 85%, which was lower than the decomposition method using a catalyst as in Examples 1 and 2. The dioxin concentration in the exhaust gas was as low as 0.1 ng-TEQ / Nm ³ or less.

(Comparative Example 1) Using a small flow reactor,
Instead of electromagnetic induction heating, outer ring direct heating was used, and all conditions such as the reaction temperature were set to be the same as those in Example 1, and a CFC decomposition experiment was performed.

Table 1 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 1, although the initial decomposition rate was lower than that of Example 1 (electromagnetic induction heating), it was relatively high at about 86.0%, but the activity was reduced after 10 hours, and after 200 hours, Degradation rate is 65
%. Furthermore, dioxins are detected from the exhaust gas, the concentration showed a high value as 5.1ng-TEQ / Nm ^3.

(Comparative Example 2) Using a small flow reactor,
Instead of electromagnetic induction heating, outer ring direct heating was used, and all conditions such as the reaction temperature were set to be the same as those in Example 2, and a fluorocarbon decomposition experiment was performed.

Table 1 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 1, it was confirmed that the CFC decomposition rate was lower than in Comparative Example 1. Further, as time passes, the catalytic activity decreases, and after 200 hours, the CFC decomposition rate becomes about 57%.
%. Furthermore, dioxins are detected from the exhaust gas, the concentration showed a high value as 4.8ng-TEQ / Nm ^3.

[0044]

[Table 1]

(Example 4) CFC12 (CF ₂ Cl ₂ ) was decomposed by using a small flow reactor having the structure shown in FIG. Using a catalyst by a combination of _Pt-WO 3 -TiO ₂ as a decomposition catalyst. In this case, Pt-WO ₃ -
The catalyst was adjusted so that the constituent molar ratio of TiO ₂ was 1: 5: 94. The catalyst is 2 cm in diameter and 2 cm in length
On a porous SiC honeycomb (with a lattice spacing of 3 mm). When the porous SiC is heated by electromagnetic induction and the catalyst layer reaches a predetermined decomposition temperature, Freon 12 and air are mixed at a Freon 12 concentration of 3.25% by volume and a gas flow rate of 15,000 cc.
/ Hr into the reactor. Further, steam was introduced to promote the hydrolysis reaction of chlorofluorocarbon and to suppress the decrease in the activity of the catalyst. The decomposition conditions are as follows. Catalyst used Pt-WO ₃ -TiO ₂ (Pt: WO ₃ : TiO ₂ = 1: 5: 94) Carrier used SiC honeycomb carrier (2 cmφ × 2 cm grid spacing 3 mm) Decomposition temperature 400 ° C. Freon concentration 3.25 volume percent Gas flow 15000 cc / hr Gas component ratio CFC: H ₂ O: Air = 1: 3: 30 Electromagnetic induction frequency 100 kHz

Table 2 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 2, the initial decomposition rate was as high as 99%. Also, 2
After a continuous experiment of 00 hours, the decomposition rate was almost constant.
The catalyst activity was hardly reduced. Furthermore, the concentration of dioxin in the exhaust gas was 0.1 ng-T
It was a low value of EQ / Nm ³ or less.

(Embodiment 5) Freon 12 in Embodiment 4
In degradation, an experiment was conducted by changing the supported catalyst to the combination of Pt-TiO _2. At this time, the catalyst was adjusted so that the Pt: TiO ₂ ratio was 1:99 in molar ratio. All other experimental conditions were set in the same manner as in Example 4. The decomposition conditions are as follows. Catalyst used Pt-TiO ₂ (Pt: TiO ₂ = 1: 99) Carrier used SiC honeycomb carrier (2 cmφ × 2 cm grid spacing 3 mm) Decomposition temperature 400 ° C. Freon concentration 3.25% by volume Gas flow rate 15000 cc / hr Gas component ratio CFC: H ₂ O: Air = 1: 3: 30 Electromagnetic induction frequency 100 kHz

Table 2 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 2, although not reaching Example 5, the initial decomposition rate was 85%.
%, And there was almost no decrease in the catalyst activity even after 200 hours. Further, the concentration of dioxin in the exhaust gas was a low value of 0.1 ng-TEQ / Nm ³ or less.

(Example 6) Using a small flow reactor having the structure shown in FIG. 1, a combustion oxidative decomposition experiment of chlorofluorocarbon using the high-temperature heat generation of a SiC honeycomb was performed. At this time, SiC
A honeycomb having the same shape and size as in Example 4 was used as the honeycomb, and methane gas was added as a combustion aid in addition to the air of the carrier. The decomposition temperature was set to a high temperature to improve the efficiency of decomposing fluorocarbons and to suppress the synthesis of dioxins. The decomposition conditions are as follows. Carrier to be used SiC honeycomb carrier (2 cmφ × 2 cm, lattice spacing 3 mm) Decomposition temperature 800 ° C. Freon concentration 3.25% by volume Gas flow rate 15000 cc / hr Gas component ratio CFC: CH ₄ = 3: 5 Electromagnetic induction frequency 100 kHz

Table 2 shows the experimental conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 2, although the initial decomposition rate was lower than that of the catalytic decomposition methods of Examples 4 and 5, it showed a high decomposition rate of 78%. Further, time course of degradation rate less dioxin concentration in the exhaust gas also showed 0.1ng-TEQ / Nm ³ or less and a low value.

Comparative Example 3 Using a small flow reactor,
Instead of the electromagnetic induction heating, indirect heating using a tubular electric furnace was performed, and all other conditions such as the reaction temperature were set to be the same as those in Example 4, and a CFC decomposition experiment was performed.

Table 2 shows the conditions and the measurement results of the decomposition rate and dioxin concentration. As shown in Table 2, although the initial decomposition rate was lower than that of Example 4 (electromagnetic induction heating), the decomposition rate was as high as 95%. However, the catalytic activity decreased with time, and after 200 hours, the decomposition rate decreased to 72%. This is presumably because in the outer ring heating method, partial unevenness occurred in the heating of the catalyst, and particularly, the catalyst in the portion where the temperature was high (heat spot) was deteriorated. Furthermore, the concentration of the detected dioxins from the exhaust gas shows a higher value as 3.5ng-TEQ / Nm ^3.

(Comparative Example 4) Using a small flow reactor,
Instead of electromagnetic induction heating, indirect heating using a tubular electric furnace was performed, and all other conditions such as the reaction temperature were set to be the same as those in Example 5, and a CFC decomposition experiment was performed.

Table 2 shows the conditions and the measurement results of the decomposition rate and the dioxin concentration. As shown in Table 2, although the initial decomposition rate was lower than that of Example 5 (electromagnetic induction heating), it was as high as 81%. However, the catalytic activity decreased with time, and after 200 hours, the decomposition rate decreased to 61%. Further, the concentration of dioxin detected in the exhaust gas was 4.2 ng-TEQ.
/ Nm ³ as a high value.

[0055]

[Table 2]

(Examples 7 to 19) By the following kneading method:
Catalyst A to Catalyst I were prepared. First, 1000 ml of pure water
Titanium sulfate solution (Ti (SO₄)₂s
ol. ) 501.5 g was dropped at a rate of 20 ml / min.
To prepare a titanium hydroxide solution. At this time, p
Ammonia water (NH) so that H becomes 6.5 to 7.5.₃
 sol. ) At the same time as titanium hydroxide
Cool the solution with ice so that the temperature of the solution does not rise. This solution
Filtration removes ammonium sulfate in the resulting solution
And remove sufficiently by filtration. Up
Add a small amount of pure water and platinum chloride to the titanium hydroxide adjusted as described above.
Acid (H₂PtCl₆・ 6H₂O) 0.66 g and tan
Ammonium gustinate (5 (NH₄)₂O ・ 12WO
₃・ 5H₂O) Add 5.64 g, and in a kneader for 30 minutes
Kneaded. After that, it is extruded and granulated by a granulator, and the catalyst particles are
Obtained. After drying the particles at 120 ° C. for 24 hours, in air
After firing at 500 ° C for 3 hours, catalyst A (0.5 wt% P
t-10wt% WO₃/ TiO₂) Got.

By the same method, when the catalyst composition is 2.0 wt.
% Pt-10wt% WO₃/ TiO ₂Catalyst
B, 0.5wt% Pt-5wt% WO₃/ TiO₂Nana
Catalyst C, 0.5 wt% Pt-20 wt% WO₃
/ TiO₂D, 2.0 wt% Pt-4
0wt% WO₃/ TiO₂Catalyst E such that
And 0.1wt% Pt-10wt% WO₃/ TiO₂To
Catalyst F, 6.0 wt% Pt-10 wt% WO
₃/ TiO₂The catalyst G was adjusted such that Also, P
Instead of t, Pd and Au are added, respectively, and the catalyst composition is
0.5wt% Pd-10wt% WO₃/ TiO₂, 0.
5wt% Au-10wt% WO₃/ TiO₂To be
Catalysts H and I were prepared.

The catalyst J was prepared by the following impregnation method. First, chloroplatinic acid (H ₂ Pt) was added to about 200 ml of water.
Cl ₆ · _6H 2 O) 0.66g and ammonium tungstate _{(5 (NH 4) 2 O} · 12WO 3 · 5H
The ₂ O) 5.64 g was added and dissolved by heating. Thereafter, 44.75 g of titania is charged and left for 2 hours. The particles were dried at 120 ° C. for 24 hours, and then calcined in air at 500 ° C. for 3 hours to obtain Catalyst J (0.5 wt% Pt-10 wt%).
WO ₃ / TiO ₂ ) was obtained.

A stainless steel tube of a fixed bed flow type reactor was filled with 5 ml of the catalyst prepared as described above, and CFC12 containing hydrocarbon (propane) was aerated, whereby the CFC decomposition rate and hydrocarbon decomposition were measured. A test was performed to determine the rate. Table 3 shows the results.

The test conditions are as follows. Catalyst amount 5ml Reaction temperature 350 ℃ Space velocity 15000h^-1(Example 17 and
18 only 10,000h ^-1) Reaction gas flow rate 1250ml / min Reaction gas composition Freon (CFC12) concentration 2% Hydrocarbon (propane) concentration 1% Steam / Freon ratio (molar ratio) 5 Air balance

As shown in Table 3, from Examples 7 to 18,
When a catalyst containing Pt, WO ₃ and TiO ₂ is used, in addition to being able to decompose chlorofluorocarbons with high efficiency, hydrocarbons can be decomposed with high efficiency and these catalysts can be used for a long time. It was confirmed that the activity could be maintained.

[0062]

[Table 3]

[0063]

As described above, according to the present invention,
Since the electromagnetic induction heating method is used, there is no radiant heat from the outer tube compared to the conventional external heating method using an electric heater, enabling rapid heating and rapid cooling, and cooling of gas after passing through the catalytic reaction layer. Speed is fast. For this reason, it is possible to suppress the generation of dioxins resynthesized from free halogens, hydrocarbons, and the like after decomposition. In addition, when the electromagnetic induction heating method is used, uniform heating is possible, and the carrier itself generates heat uniformly, so that the decomposition reaction can proceed at the same temperature on all catalyst surfaces. In addition, the decomposition efficiency is increased, and a partial deterioration of the catalyst performance due to the temperature distribution is prevented, and the operating cost can be suppressed by extending the catalyst life. Furthermore, by using a halogen-containing gas-resistant material for the catalyst carrier, the carrier is not deteriorated even when it is touched not only by the halogenated hydrocarbon gas but also by its decomposition products such as hydrogen chloride and hydrogen fluoride. In addition, stable catalytic activity can be maintained, and pollution-free treatment for decomposing halogenated hydrocarbon gas stably for a long time can be performed. Furthermore, since only electromagnetic induction heating is performed without using special processing, large-scale processing is possible, and it is economical.

Since a halogenated hydrocarbon gas can be oxidized and decomposed by combustion without using a catalyst, a heating element through which the gas passes is provided in place of the catalyst carrier, and the heating element is heated by electromagnetic induction heating. By burning and oxidizing and decomposing the halogenated hydrocarbon gas, the same effect as in the case of using a catalyst can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a halogenated hydrocarbon gas decomposition apparatus used for carrying out the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1: Decomposition apparatus 2: Cylindrical container 3: Carrier 4: Decomposition catalyst 5: Electromagnetic induction coil 6: High frequency power supply

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) // C07D 319/24 C07D 319/24 (72) Inventor Toshihiko Okada 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan Inside Kokan Co., Ltd. (72) Inventor Minoru Asanuma 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Michiki Hattori 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Stock In company

Claims (9)

[Claims] 1. A method for treating a gas containing a halogenated hydrocarbon gas to decompose the halogenated hydrocarbon gas, wherein the halogen-containing gas-resistant and conductive carrier is a halogenated hydrocarbon gas decomposition catalyst. A halogenated hydrocarbon gas-containing gas is passed through the carrier while the carrier is heated by an electromagnetic induction heating method. 2. The method for decomposing a halogenated hydrocarbon gas according to claim 1, wherein the carrier is made of at least one of SiC and stainless steel. 3. The catalyst according to claim 1, wherein the catalyst contains at least one element selected from the group consisting of Pt, Pd, Au, Rh and Ni.
3. The method for decomposing a halogenated hydrocarbon gas according to item 1. 4. The catalyst according to claim 1, wherein the catalyst contains at least one element selected from the group consisting of W, Cr, Fe, Mo and V. 3. The method for decomposing a halogenated hydrocarbon gas according to item 1. 5. The catalyst according to claim 1, wherein the catalyst is at least one element selected from the group consisting of Pt, Pd, Au, Rh and Ni, and / or a group consisting of elements consisting of W, Cr, Fe, Mo and V. The method for decomposing a halogenated hydrocarbon gas according to claim 1 or 2, wherein the method comprises at least one selected element and titania (TiO ₂ ). 6. A method for treating a gas containing a halogenated hydrocarbon gas to decompose the halogenated hydrocarbon gas, comprising heating a halogen-containing and electrically conductive heater by an electromagnetic induction heating method. A method for decomposing a halogenated hydrocarbon gas, wherein a gas containing a halogenated hydrocarbon gas is passed through the heating body while the gas is being heated. 7. The method for decomposing a halogenated hydrocarbon gas according to claim 6, wherein the heating element is made of at least one material of SiC and stainless steel. 8. A halogen-resistant, gas-resistant and electrically conductive carrier carrying a halogenated hydrocarbon gas decomposition catalyst and through which a gas containing a halogenated hydrocarbon gas is passed; An apparatus for decomposing a halogenated hydrocarbon gas, comprising: 9. A halogen-containing gas-resistant and electrically conductive heating element through which a gas containing a halogenated hydrocarbon gas passes, and a heating mechanism for heating the heating element by an electromagnetic induction heating method. An apparatus for decomposing halogenated hydrocarbon gas.