JPS5881425A - Apparatus for removing ozone - Google Patents

Abstract

PURPOSE:To obtain a simple and inexpensive small ozone removing apparatus, by using a phenolic activated carbon fiber prepared from a cured novolak fiber stock material as an ozone removing material. CONSTITUTION:A cured novolak fiber prepared by applying curing treatment with formalin to a fiber obtained by melt spinning of a novolak resin is converted to an activated carbon fiber to form a phenolic activated carbon fiber and the obtained fiber is formed into a sheet alone or along with a binder such as pulp by a papermaking process. By this sheet, an ozone decomposing catalyst such as Pt, MnO2 or Na2CO3 may be supported. This activated carbon sheet is molded into a flat plate form or a corrugated form and provided to the gas exhaust fan pat of an electrophotographic copier as a filter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for removing ozone gas contained in the air and harmful to the human body.

Ozone has strong acid (power), so it can be used to purify water, deodorize, and sterilize 1) sterilize and bleach food.

It is used for industrial sewage purification, air purification, etc.

Excess ozone or newly generated ozone is emitted into the atmosphere from these factory facilities.

21.

Conventionally, activated carbon method, combustion method 1, gas cleaning method, etc. have been used as methods for purifying ozone emitted on an industrial scale. The activated carbon method utilizes catalytic decomposition of ozone on the surface of activated carbon, and it is known that approximately 6y of ozone can be treated per 1 F of activated carbon. The combustion method takes advantage of the property of ozone being thermally decomposed at high temperatures.

The gas cleaning method involves the decomposition of ozone with alkali metal hydroxides, arsenides or carbonates, and alkali sulfites.

This method utilizes the reducing action of alkali thiosulfate, etc. These methods are less effective against ozone, which contains trace amounts of No2 gas, and are dangerous.

Each has advantages and disadvantages in terms of cost, etc.

On the other hand, in recent years, devices that generate ozone have become more common in our living environments. For example, devices with powerful ultraviolet light sources such as electrophotographic copying machines, discharge breakdown recording devices, ozone sterilization devices, projection devices, projection devices, floodlights, etc.
These include low-temperature test equipment that uses xenon lamps and high- and low-pressure mercury lamps.

Such ozone has an odor limit concentration of 0.01 ppm. O5ppm causes respiratory damage, 0
．． 1 ppm or more causes physiological effects such as shortness of breath and headache.

Measures to remove ozone from office equipment as described above naturally have limitations in terms of size, cost, etc., and the following methods have been devised.

That is, the first method is a method consisting of an activated carbon layer and a gold-acid layer. In this method, a metal acid and arsenic compound are supported on granular activated carbon, and as shown in FIG. For example, this removing device 1 is installed in a gas exhaust fan section 2 of an electrophotographic copying machine to discharge ozone generated in a corona discharge section 4 for a zero-charging drum 3 from the fan section.

Although this method of using granular activated base has a certain effect, it has a short lifespan, and in order to maintain a sufficient lifespan, it is necessary to increase the area of contact with the gas.
In order to avoid large pressure drop and trap gas inside the equipment, products with activated carbon supported on the surface of urethane foam have been devised, but the activated carbon may fall off during use, causing practical problems. There is.

The second method is to install a new electrode in the device with a polarity opposite to that of ozone ions, and attempt to capture ozone electrically. This method has the disadvantage that a large amount of dust is introduced from the outside into the photosensitive screen section including the corona charger and is attracted thereto, and a new power source is required for the electrodes having the opposite polarity.

As mentioned above, conventional ozone decomposition and removal equipment has many unsatisfactory points in terms of cost, performance, and size.On the other hand, with the spread of electronic copying machines, small, simple, and low-cost ozone removal equipment has become available. The current situation is what is required.

The present invention overcomes the drawbacks of the conventional ozone decomposition equipment as described above, and it is possible to use activated carbon fibers, especially hard [hinovolac fibers] as a raw material, by using phenolic activated carbon fibers alone or on top of these activated carbon fibers, platinum group elements, etc. Oxidation 71 ng, ng,
The present invention relates to an ozone decomposition device configured to support at least one of sodium carbonate and arsenic acid.

The present invention will be explained in detail below.

Part 2: The structure of the material used in the ozone removal device of the present invention is schematically shown. In other words, (() as shown in the figure, a non-woven fabric, paper or felt-like material consisting of activated carbon fiber 11 alone; These include those made of non-woven fabric paper such as a binder 12, and those with (a) and ←) as shown in Figure 09.

Here, a major feature of the present invention is that a nonwoven fabric or paper made from activated carbon fibers is used as the ozone removal material, and in particular, hard Hinoki and Borac fibers are used among the activated carbon fibers. The characteristics of this activated carbon fiber, nonwoven fabric, and paper making will be described in comparison with other activated carbon fibers. In general, the types of activated carbon fibers are acrylic, rayon, pitch, coconut, and phenol. Among these, all other types except phenolic carbon fiber are hard and unsuitable for various processing.On the other hand, phenolic carbon fiber is strong and has excellent flexibility, and can be used even in paper-making state. It is sufficiently durable for use.From this point of view, phenolic activated carbon fibers are more preferable as the activated carbon fibers used in the present invention.The phenolic activated carbon fibers will be briefly described below.

To make hard hinovolac fibers from phenolic resin, novolac resin is melt-spun, hardened with formalin, and three-dimensionally cross-linked. This method includes directly carbonizing and activating the raw fiber to produce a phenolic activated carbon fiber product, carbonizing the raw fiber once to produce a phenolic activated carbon fiber, and spinning the raw fiber again to create a phenolic activated carbon fiber product. There is a method of knitting, woven fabric, or felt, and then activating carbon to produce phenolic or activated carbon fiber products. Incubation is performed under a mixed gas atmosphere at a temperature of 700 to 8001::.

Such phenolic activated carbon fibers have a specific surface area of 16oO to 2000, although it varies depending on the activation treatment conditions.
It is ri7y and is the acrylic type mentioned earlier.

Rayon-based, pitch-based, and palm-based ones are 700-1
The surface area is extremely large compared to that of 400 rrr'/y. The third @ shows the benzene adsorption behavior of the activated carbon paper used in the present invention using acrylic activated carbon.

As shown in comparison with that of plain paper, the activated carbon paper 21 of the present invention adsorbs about twice as much benzene as the acrylic thread 22, and the butterfly adsorbs almost no benzene with the plain paper 23. I understand that you can't see it.

As mentioned above, the flexibility of phenolic activated carbon fiber,
The large surface area is a major feature of the ozone pig removal device of the present invention. These features will be explained below in comparison with a conventional ozone removal device using activated carbon method.

Ozone is 160-200℃! It is very easily decomposed at temperatures below 100°C, but is stable at temperatures below 100°C. For this reason, ozone is decomposed at a temperature close to room temperature.Mochima 58-814
25(3) Various catalysts have been proposed for this purpose. Typical of these are diacid “himanganese” and platinum group elements.

These include sodium carbonate and activated carbon. - Removal of ozone by activated carbon involves not only the reaction by catalytic decomposition of ozone itself as shown in equation (1) below, but also the reaction shown in equation (2), (
It can also be carried out by an acid reaction with activated carbon itself as shown in 3).

03→o2...(1)
C+03→CO2+1/202II 61111111
1(2)C+ 203→CO2+ 2.0211111
+11@@ (3) In this way, activated carbon can be used as a catalyst (
While acting as shown in equation (1), it also consumes itself as shown in equation (2) I and (3). For this reason, in the conventional method using a packed bed of activated carbon particles, it is necessary to fill the bed with an excessive amount of activated carbon particles in advance, and the life of the device is very short, especially when the device has a large RB.

Furthermore, as described above, if the thickness of the activated carbon layer is increased to increase the contact area between the gas and the same substance, the pressure loss will increase and the device will instead be filled with air.

9. The phenolic activated carbon fiber paper of the present invention has very great features in overcoming the drawbacks of the conventional methods.

In other words, since the surface area is larger than other types and shapes of activated carbon fibers, the rate of consumption of activated carbon due to its own reaction with ozone is extremely small compared to the total surface area, resulting in a longer service life than conventional fibers. Become.

Furthermore, since the paper and nonwoven fabric are flexible, they can be molded into various shapes with 0T capability, and the relationship between pressure drop and gas-solid contact area can be made advantageous. FIG. 4 shows various shapes of the ozone removal device of the present invention, and various processing is possible to increase the contact area between ozone and activated carbon paper.

Although there are various possible installation examples of the device of the present invention, the following two are typical. Taking an electronic copying machine as an example, the first is an example in which a filter is installed in the discharge port 77 of the main body of the copying machine, and is used as shown in FIG. In this case, the material of the present invention can be molded into shapes as shown in FIGS. 4(a) and 4(b). (A) shows a flat paper 31 and a corrugated paper 1o (.

(b) is an example in which a long paper 33 is folded in a zigzag shape. Arrows ~ indicate the direction of travel of gas containing ozoi. 1g2 is used as shown in Figure 4 (c) and d).

That is, the paper 3 is attached to the inner wall of the outer frame 34 of the corona discharge section.
6 is brought into contact with each other. In this case, a conductive adhesive 36 such as silver paint may be interposed between the activated carbon paper 36 and the outer frame 34 in order to release the charged charges. In addition, if the activated carbon paper 37 is formed into a wave shape and installed on the wall surface of the frame as shown in Figure 4), the contact area with the generated gas will increase, and the ozone decomposition efficiency will be further improved. Especially the 4th
The reason why the paper of the present invention can be used as shown in Figs.
It is very effective as an installation example for quickly decomposing ozone gas generated by high-pressure discharge between the outer frame body 34. Also, in any of the above shapes and installation examples, it is also possible to use it as a paper filter. Moreover, since it is used by crucifixion, even when the ozone gas decomposition capacity reaches the end of its lifespan, it can be easily replaced with a new one.

Furthermore, the present invention includes a method of supporting various ozone decomposition catalysts on activated carbon fibers while taking advantage of the characteristics of phenolic activated carbon fibers as described above. As these ozone decomposition catalysts, manganese oxide, iron oxide, sodium carbonate, etc. are most suitable, and their supporting methods and custom orders will be described in the section of specific examples.

Next, specific examples of the present invention will be shown.

Example 1 Consisting of 60% phenolic activated carbon fiber and 6096 binder mainly composed of valves, thickness α2tran.

Activated carbon paper with activated carbon basis weight eoy 7nr', Example 2 The above activated carbon paper was immersed in an aqueous chloroplatinic acid solution of 06 mol/e and reduced to platinum in a hydrogen reducing atmosphere to support a platinum layer on the paper. 1, - Example 3 The above activated carbon paper was immersed in an aqueous sodium carbonate solution and air-dried. 14 Compound 858-81425 (4) Example 4 M
Example 6 Fe2O was formed on the above activated carbon paper by electroless plating rC.
The 41st F with the above 6 types of materials that precipitated two layers! (1'JA) We made an ozone removal device with the shape shown here, passed 0.6 ppm of ozone through it, measured the ozone concentration after passing, and determined the ozone removal rate.As a comparative example, we used only granular activated carbon. Experiments were also conducted using a commercially available conventional filter consisting of: The following table shows the ozone removal rate over time.

3. As described above, the ozone removal device of the present invention is small and simple, and is particularly suitable as an ozone removal device for small devices such as electrophotographic copying machines.

However, since the activated carbon fibers used in the device of the present invention are electrically conductive, the main body generates heat when an appropriate current is applied during use. As mentioned earlier, ozone 1l-j:1
Considering that the decomposition rate is accelerated in an atmosphere of 00°C or higher, this method makes it possible to decompose ozone at high temperatures, further increasing the effects of the present invention.

[Brief explanation of drawings]

Fig. 1 is a schematic vertical cross-sectional view showing an example of the installation of an ozone decomposition device in an electronic copying machine, Fig. 2 is a schematic diagram showing the structure of the activated carbon material used in the device of the present invention, and Fig. 3 is a hardened carbon material used in the device of the present invention. Figure 4 shows a comparison of benzene adsorption and desorption properties of novolac activated carbon fibers with that of a conventional example; Figure 4 shows some shapes of the device of the invention; It is a figure showing an example of installation. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Fig. 4 Fig.2

Claims (2)

[Claims] (1) An ozone removal device made of a nonwoven fabric, paper, or felt made of phenolic activated carbon fibers made from cured novolac fibers and other fibers. (2) The ozone removal device according to claim 1, wherein the nonwoven fabric, paper, or felt supports at least one of a platinum group element, manganese oxide, sodium carbonate, and iron oxide.