JPH07106318B2 - Heating element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, hot water supply, drying, cooking, refrigeration, to a heating element that having a deodorizing function in air-conditioning equipment.

[0002]

Conventionally, as the deodorizing method of malodorous substances, deodorant
Spraying agents, adsorbing odorous components on activated carbon or zeolite that is porous and has a large adsorption capacity , or contacting heated catalysts with odorous components to deodorize them by oxidative decomposition ,
Recently, methods oxidation decomposing malodorous gas component by placing the equipment which gave ozone generating function in the room by the ozone gas
Etc. have been adopted .

On the other hand , in the conventional heating element, a ferrochrome wire, a nichrome wire, a kanthal wire or the like is used as an electric resistor and aluminum is used.
Metal tube so as not to short with Na or magnesia
There are those built electrically insulating <br/> quartz tube with a sheath heater or a hollow heat resistance which is incorporated, ceramic tube, the electrical resistor on the glass tube or the like. Further cordierite to the tubular heating body outer surface, clay, glass walk those coated nickel oxide, the far-infrared high radiation material such as iron oxide, or certain
Such as a ceramic heater obtained a ceramic sintered
There was. Feeding the hot water, drying, cooking, refrigeration and air-conditioning equipment directly above the heating element heating, or force a temperature by blowing air wind by the fan to the heating element, a reflector is provided behind the heating element The object to be heated is heated by, for example, radiant heating.

However, the conventional deodorizing method has the following problems. That is, when performing deodorization by adsorption of odorous as activated carbon or zeolite had to lever replaced reaches the adsorption saturation. Further, when performing deodorization with a catalyst, there is a problem that deodorization cannot be performed unless the catalyst is heated to an activation temperature or higher . Furthermore, the oxidative decomposition of odor components with ozone, in order to control the optimal ozone generation concentration decomposition deodorization, and it must be equipped with a special device, Ri difficult odor components there is decomposed by ozone, further The life of the ozone generator is
Comparatively short, it is such as Ru problem entirety in Gerare.

Further, when a noble metal as in the prior art had use a supported catalyst in the zeolite surface, odor components zeolite
If greater than the pores of the bets, because it can not odorous component enters the pores, since the noble metal present in the zeolite pores (about a few angstroms) can not function effectively deodorizing effect
The fruit is low.

[0006]

[SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, there is provided a heating element for removing odors and harmful gases over long periods <br/> with a simple construction is there.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a quartz or glass body having a hollow tubular shape containing an electric resistor on the outer surface thereof.
Olite powder, precious metal, alumina, inorganic vine
A heating element to form a silica or Ranaru catalytic coating layer as loaders.

[0008]

[Function] In the present invention, a hollow tube containing an electric resistor
For the quartz or glass body outer surface is provided with a catalytic coating layer, the heating element generates heat by energization, while heating the body or object to be heated, the catalyst coating layer is also heated simultaneously becomes Rukoto. Because the catalyst coating layer of this covers the periphery of the heating element, radiation from electric resistor, by heat transfer, the heat absorbed efficiently, the catalyst coating layer is heated to the activation temperature in a short time the catalyst . Air heating element near, lever to contact the catalyst has been heated above the activation temperature, odorous components in the air, for example, ammonia or fatty acids, is oxidized and decomposed by the catalytic action
It is deodorized and purified.

[0009] The, the catalyst coating layer, since contain a zeolite having superior adsorption properties, when not energized electrical resistor, odor components are adsorbed. In this case, zeolite adsorption capacity, when the reach saturation, by energizing the electric resistor, odor components adsorbed is Ri <br/> oxidative decomposition by the catalyst, the zeolite Ru played.

[0010] In addition, the present invention is usually zeolite at room temperature
Odor components adsorbed on the bets, by intermittently energizing the heating elements, it is used as a deodorizer for a long period of time
It is possible.

The above operation has been described in the case of natural convection that occurs in the vicinity of the heating element, but a more remarkable effect can be obtained in the case of a warm air blower forcibly blowing air to the heating element with a fan or the like .

[0012]

EXAMPLES Examples of heating elements according to the present invention will be described below.
I will explain in detail. First, a hollow tube containing an electric resistor
Coating layer formed on the outer surface of quartz or glass
The material, composition, etc. will be explained.

[0013] In the present invention, with the zeolite powder
And aluminum oxide (Al _Two O _Three : Hereinafter referred to as alumina
To do. ) Mixing catalyst powder with precious metal supported on the surface
Therefore, the deodorizing function is fully exerted. In addition, aluminum
Simultaneous loading of rare earth oxides and other promoters on the surface
As a result, the catalytic activity can be further improved.

[0014] In the present invention, the precious metal or the precious metal and the auxiliary
As the alumina of the carrier that supports the catalyst simultaneously,
Highly stable and stable α-alumina, β, γ, δ,
Theta, η, ρ, and χ type metastable alumina are suitable. Carrier
The content of alumina is 20 to 6 in the catalyst coating layer.
It is desirable that the range is 0 wt%. Alumina content
If the ratio is less than 20 wt%, the catalyst powder is in the catalyst coating layer.
Since it cannot be dispersed in a wide range, it exhibits a sufficient catalytic function.
It's hard to do. Also, the alumina content exceeds 60 wt%.
As a result, the ability of the catalyst to absorb odor decreases.

As the noble metal, platinum (Pt) or para
It was desired to use the indium (Pd). Especially Pt and P
When mixed with d , it is more effective for deodorizing various odorous components . Ruthenium is used for oxidative decomposition of Pt and Pd.
Higher than (Ru) and iridium (Ir) , Pt and P
This is because the further a high activity by using a mixture of a d. Also, Ru in the case of use at high temperatures, it is necessary to note detrimental to Ru is volatilized.

Next, it is desirable that the catalyst coating layer Maseru containing cerium oxide as a co-catalyst. This is because it is Rukoto improved catalytic oxidative decomposition activity to hydrocarbon compounds. 2 cerium oxide content in the catalyst coating layer
It is desirable that the content be ˜15 wt%. The oxidative decomposition characteristic of the catalyst when the content of cerium oxide exceeds 15 wt% is
On the contrary, it decreases, and if it is less than 2 wt%, a sufficient addition effect of cerium oxide cannot be obtained .

In the catalyst coating layer, a catalyst similar to cerium oxide is used as a catalyst.
It is also effective to Maseru contains barium oxide as a medium. The content rate of barium oxide in the catalyst coating layer in the present invention is preferably 0.5 to 5 wt%. When the content of barium oxide is more than 5 wt% reduces the adhesion of the catalyst coating layer, and in less than 0.5 wt% can not be obtained a sufficient effect of adding barium oxide.

[0018] Similar effects of adding even with barium carbonate in place of the barium oxide is obtained. The desirable amount of barium carbonate added is 0.
It is 5 to 5 wt%.

[0019] The specific surface area of the catalysts powder is desirably ^{10 m} 2 / g or more. This is because, as the specific surface area of the catalyst powder increases, the far-infrared radiation amount ratio increases as compared with the near-infrared radiation amount emitted, but the specific surface area is 10 m ² / g.
This is because a sufficient far-infrared radiation amount ratio can be obtained by the above.

[0020] Various zeolites as zeolite powder is Ru used <br/>, among them, because the copper ion-exchanged A-type zeolite adsorption properties of odorous is most excellent, the present invention
This was mainly adopted in.

Furthermore, as the inorganic binder, silica is excellent in most binding property, without lowering the catalytic properties, peeling from the substrate when the quartz substrate, a glass surface to form a catalytic coating layer It is possible to form a coating that is difficult to do.

The content of silica of the present invention is preferably a 10 to 40 wt% in the catalyst coating layer. Silica content
If the ratio exceeds 40 wt%, cracks are likely to occur in the catalyst coating layer, and the adhesiveness is likely to deteriorate. If it is less than 10 wt%, a sufficient adhesion effect due to silica cannot be obtained.

[0023] Rutoki to form a catalyst coating layer, either by roughening the quartz or glass tube outer surface, was thoroughly degreased, it is desirable to provide a catalyst coating layer. These processes, square
More law can Rukoto improve the adhesion between the quartz or glass tube outer surface and the catalytic coating layer.

[0024] The present invention is a hollow tubular body containing an electric resistor.
Zeolite powder on the outer surface of the quartz or glass body of
Noble metal, alumina, and silica as an inorganic binder
A catalyst layer made of mosquito is formed. With this material composition
This not only improves the catalytic action of precious metals for oxidative decomposition.
In addition, the adsorption characteristics can be improved. Ie
By using alumina and zeolite simultaneously,
More acidic odor component than using Mina or Zeolite alone
It is possible to obtain a synergistic effect of improving the adsorption characteristics for
Wear.

[0025] As a method for forming the catalyst coating layer of the present invention <br/> it can be used a variety of methods. For example, spray coating, dip coating, electrostatic coating, roll coating method, Ru screen printing method Nadogaa Gerare.

A typical embodiment of the heating element of the present invention is shown in FIG.
Shown in. In FIG. 1, 1 is a nichrome wire, 2 is a quartz tube, 3
Is a catalyst coating layer, 4 is an insulator, and 5 is an air flow.

[0027] A specific example below. Example 1 An outer peripheral surface of a quartz tube having an outer diameter of 10 mm, an inner diameter of 9 mm and a length of 344 mm is degreased and washed.

On the other hand, it was supported Pt .gamma.-alumina 160
g, 400 g of a silicic acid colloid aqueous solution containing 20 wt% in terms of silica , 200 g of water, and 160 g of copper ion-exchanged A-type zeolite powder were sufficiently mixed using a ball mill to prepare a slurry A. The average particle size of this slurry A was 4.5 μm. This slurry A was applied to the entire circumference by spraying, leaving 33 mm on both sides of the outer peripheral surface between the quartz, and then dried at 100 ° C. for 2 hours, followed by 5
Bake at 00 ° C for 1 hour to dehydrate the silicate colloid ,
A quartz tube provided with the catalyst coating layer 3 was prepared. The coating weight is 1.0 g and the Pt content is 25 mg.

A 40 Ω coil-shaped nichrome wire 1 was incorporated in this quartz tube, and a heating element A having a catalyst coating layer which was insulated and held on both sides of the quartz tube by an insulator 4 was prepared.

In addition, chloroplatinic acid, alumina and copper ion exchange
A conversion A-type zeolite and硅 acid colloid solution, and water were mixed sufficiently in a ball mill to prepare a slurry B. Using this slurry B, a heating element B in which a copper ion-exchanged A-type zeolite or silica was also loaded with a noble metal was prepared. The coating weight and the Pt content were the same as those of the heating element A.

[0031] were compared for the heating elements A and B perform <br/> oxidation cleaning test of isovaleric acid, the heating element having no catalytic coating layer. The oxidation purification test of isovaleric acid was 250 liters.
Place the heating elements in a container made of fluororesin torr cube, to where the temperature of the outer surface of the center of the heating body is heated so as to be 450 ° C., isovaleric acid to a concentration of the 40ppm It was carried out by injecting it into a container and examining the change over time in the concentration. The time course of isovaleric acid concentration was examined by gas chromatography. The results are shown in (Table 1).

[0032]

[Table 1]

[0033] As Table 1 is apparent, by Rukoto to form a catalyst coating layer on the heating element, it is possible to remove odor components. Also, calling Netsutai B also copper ion-exchange A-type zeolite and silica was supported precious metal had a lower activity than calling Netsutai A having supported thereon a noble metal only on the alumina surface. This is because the odor component is larger than the zeolite pores,
Odor component <br/> Me was difficult to enter into the zeolite pores, the noble metal present in the zeolite pores (about several angstroms) is believed to be due to not function effectively. Contact to the present invention reverse to Ru in the presence of a noble metal on alumina surface
As a result, the function of the supported precious metal can be fully exerted.

[0034] Next, the methyl mercaptan adsorption test heat generating A, was compared to the heating element without conventional catalyst coating layer does not have a catalyst coating layer according to an embodiment of the present invention. In the methyl mercaptan adsorption test, the heating element is placed in a 250 liter cubic container made of fluorocarbon resin, the heating element is not heated, and methyl mercaptan is injected into the container so that the concentration becomes 8 ppm and the concentration changes with time. It went by investigating. The change with time of the methyl mercaptan concentration was examined by gas chromatography. The results are shown in (Table 2).

[0035]

[Table 2]

As is clear from (Table 2), the inclusion of zeolite in the catalyst coating layer enables deodorization by adsorption at room temperature.

[0037] (Embodiment 2) Next, in order to examine the optimal zeolite was investigated adsorption capacity of various zeolites. First, in the slurry A prepared in Example 1, a slurry was prepared by replacing the copper ion- exchanged A- type zeolite in the slurry with another ion-exchanged zeolite. Each of these slurries is then hollowed by dipping so that the film thickness becomes 150 μm.
Coated on tubular quartz, calcined at dried 500 ° C., the catalyst to be
Kutsugaeso were formed.

[0038] These catalyst body, odor components adsorbed capacity of each catalytic body at room temperature, as in Example 1 using methyl mercaptan (8 ppm) is typical odor components same
It was a test of the like. The test method is the same as in Example 1
Retain the methyl mercaptan in the container using a bottle
The time required to reduce the survival rate to 20% (Methyl Merca
The putan removal time) was measured and evaluated. The results are shown in (Table 3).

[0039]

[Table 3]

As is clear from (Table 3), the copper ion-exchanged A-type zeolite gives methyl mercaptan in the shortest time.
Odor components adsorbed capacity because it can be removed copper ion-exchange A
Type zeolite is it is thought to be the most excellent and desirable.

[0041] In slurry A was prepared in (Example 3) Example 1, bind to the silicate colloid aqueous solution in the slurry, contained in final solids
As the amount of loaders are the same, the slurry is replaced with a variety of non-quality protein binder <br/> prepared, were prepared in the same manner as in the heating element. In order to investigate the film hardness of these catalyst coating layers, a pencil hardness test of JIS G-3320 was conducted. Further, for each heating element, an isovaleric acid purification test was conducted in the same manner as in Example 1, and the residual rate after 10 minutes was obtained.
The results are shown in (Table 4).

[0042]

[Table 4]

As shown in (Table 4), when alumina sol or bentonite is used, the film hardness is reduced, and when Li silicate or water glass is used, the film hardness is improved, but the film is not porous and the catalytic activity is decreased. I understood it. As described above, silicate colloids water as an inorganic electrolyte binder
By using silica generated from the liquid, a strong coating can be formed without lowering the catalytic activity.

[0044] In slurry A prepared in Example 4 Example 1, based on the total solid content in the slurry, a variety of content between 5～60Wt% by converting the silicate colloidal aqueous silica A slurry in which the amount of increased silica was reduced by alumina was prepared, and using this, a heating element was formed in the same manner as in Example 1 in which 1.0 g of the catalyst coating layer was formed on the entire outer peripheral surface of the quartz tube. A thermal shock test was performed on these heating elements to examine the adhesion of the catalyst coating layer. Thermal shock test, were energized electrical resistors incorporated in the quartz tube, the surface temperature of the central catalytic coating layer was set for each 25 ° C., it was maintained at that temperature for 10 minutes, then put into water of room temperature catalytic coating The layer was checked for peeling, and the maximum temperature at which peeling did not occur was taken as the thermal shock resistance temperature. The results are shown in (Table 5).

[0045]

[Table 5]

[0046] (Table 5) than seen, best adhesion with content of less 10 wt% or more 40 wt% of the silica is evident obtained Rukoto.

[0047] In slurry A (Example 5) Example 1 Al supporting the noble metal
Aluminum that does not carry precious metals for catalysts instead of mina
Comparative Slurry 1 using Na, containing no precious metal for catalyst,
And all the alumina of the carrier is copper ion exchange A type Zeoli
Comparative Slurry 2 and Comparative Slurry 1 with
All ion-exchanged A-type zeolites carry precious metals
Example 1 using Comparative Slurry 3 with no alumina
Comparative example with 1.0 g of each catalyst coating layer similar to
Heat bodies 1, 2, and 3 were produced.

[0048] Acetic acid adsorption test for comparative heating elements 1, 2 and 3
A test was conducted, and the acetic acid residual rate of 100 minutes after the start of measurement was determined by the present invention.
It was compared with the heating element A. The results are shown in (Table 6).

[0049]

[Table 6]

[0050] As is clear from (Table 6), acidic odor formation
The heating element A of the present invention is
Was superior to the comparative heating elements 1, 2, 3. Therefore,
Zeolite powder with precious metal supported on the surface of lumina and zeolite
Alumina and zeolite can be obtained by using powder at the same time.
Characteristics of Acid Odor Components Compared to Using Alone
It is possible to obtain a synergistic effect of improving

[0051] (Example 6) Cerium nitrate 6 in various quantitative ratios was added to Slurry A of Example 1.
Hydrochloric acid was added, and the same method as in Example 1 was followed to remove the quartz tube.
With the same amount of catalyst coating layer as the heating element A on the surface, cerium nitrate
The cerium oxide content produced by thermal decomposition of the catalytic coating
Different heat generation as shown in (Table 7) for the whole layer
The body was made. The increase of cerium oxide in the catalyst coating layer
Minutes were prepared by reducing the amount of γ-alumina.

[0052] For these heating elements,
Sovaleric acid was selected and this isovaleric acid purification test was carried out in Example 1.
I went the same way.

[0053] The test method was the same as in Example 1, except that
Put the heating element in the closed box of the tor and let the air inside the box
Dilute 40 ppm concentration of isovaleric acid at 450 ° C.
Contact the heating element to oxidize and decompose it,
Measure the current-carrying time required for 80% of herbate to disappear
It was The results are shown in (Table 7).

[0054]

[Table 7]

[0055] As shown in (Table 7), cerium oxide
Of the hydrocarbon compound
The catalytic oxidation activity for Oxidation
If the cerium content exceeds 15 wt%, the catalyst will be oxidized.
The solution property begins to deteriorate, and if it is less than 2 wt%, the cerium oxide
Since it is not possible to obtain a sufficient addition effect of um,
The desirable content of um is 2 to 15 wt% in the catalyst coating layer.
Is.

[0056] (Example 7) Various amounts of barium oxide were added to the slurry A of Example 1.
The same procedure as in Example 1 was applied to the outer surface of the quartz tube.
Includes barium oxide in the same amount of catalyst coating as heating element A
The rates are as shown in (Table 8) for the entire catalyst coating layer.
Different heating elements were prepared. The oxidation in the catalyst coating layer
The barium increase was prepared by reducing the amount of γ-alumina.

[0057] For these heating elements,
Sovaleric acid is selected and this isovaleric acid Purification test Example 1
I went the same way.

[0058]

[Table 8]

[0059] Touch barium oxide as shown in (Table 8).
By including it in the medium coating layer,
The catalytic oxidation activity can be improved.

[0060] Barium oxide content exceeds 10 wt%
Then, the adhesiveness of the catalyst coating layer begins to decrease, and 0.5w
If it is less than t%, a sufficient addition effect of barium oxide cannot be obtained.
Therefore, the desirable content of barium oxide is the catalyst coating.
It is 0.5 to 5 wt% in the layer.

[0061]

As described above, the heating element according to the present invention is electrically charged.
Outside of the quartz or glass of the hollow tubular with a built-in air resistance
Zeolite powder with excellent adsorption properties on the surface and precious metal for catalyst
From genus, alumina and silica as an inorganic binder
A heating element with a catalyst coating layer
If the odorous components in the air of the
Wear and heat the body or the object to be heated by the heat generated by energizing
At the same time, the catalyst in the catalyst coating layer is heated to the activation temperature in a short time.
Raised and adsorbed by the zeolite powder in the catalyst coating
Adsorption ability of zeolite powder by oxidative decomposition of odor components
The odor component in the air around the heating element
It is effectively decomposed and deodorized for purification.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a heating element according to an embodiment of the present invention.

[Explanation of symbols]

 1 Nichrome wire 2 Quartz tube 3 Catalyst coating layer 4 Insulator 5 Air flow

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number for FI Technical indication C03C 17/36 H05B 3/44 7512-3K (72) Inventor Yasue Yamade Kadoma City, Osaka Kadoma 1006, Matsushita Electric Industrial Co., Ltd. (56) Reference Japanese Patent Laid-Open No. 63-7845 (JP, A) US Patent 3779710 (US, A)

Claims (4)

[Claims] 1. Zeolite powder and a noble metal are provided on the outer surface of a hollow tubular quartz or glass body containing an electric resistor .
A heating element having a catalyst coating layer formed of alumina and silica as an inorganic binder . 2. The noble metal is previously supported on alumina.
The heating element according to claim 1, wherein: 3. A heating element according to claim 1 or 2 wherein the zeolite is a copper ion-exchange A-type zeolite. 4. A catalyst is formed on the surface of alumina together with a precious metal for a catalyst.
Cerium oxide, barium oxide and burr carbonate as catalysts
At least one selected from the group of um is added and supported.
4. The catalyst powder according to claim 1, wherein the catalyst powder is used.
Heating element.