JP4150450B2 - Catalytic reaction apparatus and catalyst excitation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention relates to a catalyst excitation energy in a technical field for purifying an environment contaminated with a harmful substance by utilizing catalytic action such as deodorization, antifouling, SOx / NOx removal, and a field where a conventional catalyst or photocatalyst has been used. The present invention relates to a catalyst excitation technique in a technical field substituting for heat or light energy used as a light source or in a technical field where photocatalytic action is required but heat or light energy cannot be applied.
[0002]
[Prior art]
Photocatalyst related
(1) W096 / 29375
"Method for making the surface of a substrate photocatalytically superhydrophilic, a substrate having a superhydrophilic photocatalytic surface, and a method for producing the same"
(2) JP-A-2-273514
"Removal and removal method of antioxidant harmful substances"
Photocatalyst (expressed as a semiconductor with a forbidden band of 0.5-5 eV)
Irradiate UV to remove harmful substances.
[0003]
Discharge-related catalyst
(1) Reality 6-45975
"Corona discharge device"
It is intended to remove ozone by using a conductive shield made of corrugated cardboard sheet made of activated carbon paper. Further, as an existing technique, an ozone decomposition catalyst is disclosed in which metals such as manganese dioxide, lead peroxide, palladium, platinum, nickel, rhodium and metal oxides are supported on activated carbon.
(2) Japanese Patent Publication No. 7-015602
"Corona discharge device"
A shield member is formed from an activated carbon fiber material carrying a metal or metal oxide (manganese oxide).
[0004]
(3) JP-A-5-088504
"Ion generator"
Charging device with low ozone generation
Ozone decomposition catalysts are generally known as ozone decomposition catalysts such as platinum on wire mesh, copper oxide and nickel other than platinum.
[0005]
(4) No. 2633756
"Electrophotographic equipment"
The present invention relates to a catalyst layer of an air filter. As the catalyst, CuO, MnO₂And catalysts containing water-soluble polymers are disclosed.
(5) JP-A-6-317974
"Corona discharge device"
The electrode shape is serrated and a catalyst is placed around it. Ozone generation is as low as about 1/4 compared to wire.
[0006]
(6) JP-A-8-062928
“Charging device and image forming apparatus using this charging device”
Charging is performed by a contact charging member (blade).
(7) JP-A-5-088507
`` Charging member ''
Charging is performed by a contact charging member (roller).
[0007]
(8) JP-A-5-173402
"Charging brush"
Charging is performed by a contact charging member (brush).
(9) JP-A-5-119585
"Corona discharge device"
Although there is no description of a photocatalyst, an ozonolysis accelerator is coated on the inner peripheral side of the shield. The material name of the ozonolysis accelerator is selected from metal oxides such as manganese dioxide, lead dioxide and platinum, and metals. The binder is a conductive resin composition or a conductive rubber composition.
[0008]
Catalyst related
(1) JP 7-134473 A
"Corona discharge device"
Corona discharge device A plate-shaped insulating catalyst for ozone decomposition is installed at or near the open end of the shield case side of the corona discharge device to reduce the amount of ozonozone in the shield case and control the ion flow to stabilize the discharge. Let
(2) JP-A-5-261246
"Deodorizer and its operating method"
A bad odor is adsorbed by the catalyst, and the catalyst is regenerated and activated by decomposing the odor component adsorbed and adsorbed on the catalyst by ozone generated by the discharge phenomenon.
(3) Japanese Patent No. 2625811
"Ozone decomposition catalyst"
Ozone decomposition catalyst with manganese oxide and flame retardant supported on activated carbon. Formed inside the corona discharge shield.
[0009]
The photocatalyst has been announced by Japan regarding the electrolysis of water using a titanium oxide photocatalyst [Fujishima. A. Honda. K. Nature, Vol. 238, JULY (1972) p37-38], since then, its applied development has been widely promoted and has been actually used in products.
[0010]
For example, it has been developed in various application fields such as antibacterial, deodorizing, antifouling, environmental purification, energy conversion, and surface modification (for example, WO96 / 29375). However, since the excitation means has been expanded to be limited to light, as a matter of course, its use is limited to the extent that light can be applied. Of course, it is preferable from the viewpoint of LCA (Life Cycle Assessment) to use sunlight as an energy source that does not cost if it is outdoors.
[0011]
However, taking air pollution purification as an example, the light necessary for excitation of the most frequently used titanium dioxide photocatalyst is ultraviolet light of 400 nm or less, which is contained only 4 to 5% in sunlight. Therefore, it is possible to treat pollutants such as SOx and NOx in a normal pollution concentration environment of 10 ppm level. However, when the pollution concentration is 100 ppm or more, it cannot be said that the amount of excitation energy is sufficient. material". Vo1.44, no. 8 (1996) P107].
[0012]
Thus, there are limitations to high concentration processing. In addition, the final function can be obtained when the device is added with illumination that generates special ultraviolet light, but there are drawbacks such as the fact that the incidental to the function expression such as generation and shielding of ultraviolet light tends to be large. is there. There is also a demand for use in places where ultraviolet light cannot be introduced.
[0013]
If the catalytic action can be obtained by excitation means other than ultraviolet light, the range of applications will be further expanded. In particular, with increasing interest in environmental issues in recent years, it is important to present further application development in the field of environmental purification. As an example, generation of harmful gas by a charging mechanism is given as an environmental problem of the image forming apparatus. That is, in many image forming apparatuses, the photoconductor is charged using corona discharge, but ozone (O₃) And nitrogen oxides (NOx) are generated, resulting in a deterioration in the off-ice environment and a decrease in the life of the OPC photoreceptor. When no measures are taken, the ozone concentration just below the charger is 1 to several tens of ppm, and the nitrogen oxide concentration is N0.₂It is said to be 0.01 to 0.1 ppm in terms of conversion.
[0014]
On the other hand, when the influence on the human body is taken into consideration, a value of 0.1 ppm is shown as a recommended ozone allowable concentration value by the Japan Industrial Hygiene Association. Efforts have been made to make 0.02 ppm or less. At the present stage, corona discharge wire materials are changed and the generation and reduction of harmful gas filters are carried out ["Electrophotographic process technology", published by Triqueps Co., Ltd. (1992). P60].
[0015]
Among these, the catalyst used for reducing the discharge products by the ozone decomposition catalyst and the filter is activated carbon, platinum, copper oxide, nickel (Japanese Patent Laid-Open No. 5-088504) or manganese oxide (Japanese Patent Publication No. 7-015602). Etc. As another technique that does not generate ozone, an electrode is formed in a sawtooth shape, and a catalyst is disposed around the electrode (Japanese Patent Laid-Open No. 6-317974), a roller (Japanese Patent Laid-Open No. 5-88507), a brush (Japanese Patent Laid-Open No. 5-173402). ), Flade (Japanese Patent Laid-Open No. 8-62928), and the like, which are intended to reduce discharge products by charging with a contact charging member. However, at present, the corona charging method is frequently used in many image forming apparatuses.
[0016]
On the other hand, since the photoconductor used in the image forming apparatus uses a material (photoconductive material) that causes an electrical change by light, an ultraviolet light source is introduced into the image forming apparatus, thereby causing air pollution. In general, it is difficult to remove harmful gases using a photocatalyst for purification.
[0017]
The next example is an air cleaner. Many catalysts are also used in deodorizers, but ozone is generated by an ozonizer, the odor is decomposed and deodorized by the action of the ozone, and the catalyst itself does not function to deodorize, but the odor component It is a role as a thing to adsorb | suck. An example of this is JP-A-5-261246. Further, when a photocatalyst is used as a harmful substance removal technique, ultraviolet rays are used as disclosed in JP-A-2-2735104 and JP-A-3-23310, except that sunlight or an ultraviolet component in a weak fluorescent lamp is used. . Therefore, it is limited to the scope of technology that can use light.
[0018]
[Problems to be solved by the invention]
  The present invention relates to an apparatus for catalytic reaction that excites a catalyst (hereinafter also referred to as a photocatalyst or a semiconductor catalyst) that is excited by light and causes chemical changes of oxidation and reduction without using light or heat, andImage forming apparatus using the sameThe purpose is to provide.
[0019]
[Means for Solving the Problems]
  The present inventionGaseous organic substances containing at least one element selected from carbon, hydrogen, oxygen, nitrogen and sulfur, or gaseous mixtures containing the organic substances, or nitrogen, sulfur and phosphorus An apparatus for catalytic reaction capable of decomposing and removing at least one gaseous substance selected from oxides or oxides or a gaseous mixture containing the gaseous substance, and (i) excited by light A catalyst having a property of causing a chemical change of oxidation and reduction or a layer containing the catalyst, and means for exciting the catalyst with an electron beam; ii The catalyst reaction apparatus characterized in that the catalyst or the layer containing the catalyst with respect to the means for exciting the catalyst has conductivity and can move periodically. Image forming apparatus using the apparatusBy providing the above, the above problems could be solved.
  In addition, according to the present invention, since the catalyst is excited by the action of electrons or ions, the catalytic effect is always maintained in the state of use.
[0020]
The photocatalyst used in the present invention is a photocatalyst that is generally known as a photocatalyst, a substance that improves the activity of the photocatalyst, for example, a substance that is carried on a metal, a substance that can adsorb a contaminant, such as activated carbon, Catalysts such as those supported on an adsorbent such as zeolite to increase the catalyst efficiency can be mentioned.
[0021]
  In the case of electron beam excitationSince the catalyst layer is gradually charged up due to the charge of electrons or ions, it is preferable to make the catalyst layer conductive in order to release the accumulated charge. As a specific means for imparting conductivity to the catalyst layer, a catalyst having conductivity from the beginning is used, impurities are doped, or an electron donating component is excessively compared with an exact stoichiometric ratio. A means of using the provided catalyst is mentioned.
[0022]
In addition, the substrate of these reaction devices or the substrate in contact with the layer containing at least the catalyst or catalyst has conductivity, for example, the contact surface of the substrate or the substrate and the catalyst is metal. Alternatively, it is preferable to have conductivity such as a metal film because it is easier to prevent the catalyst layer from being charged and to easily release the charge.
[0023]
Further, the active irradiation means (particularly the electron beam irradiation means) may be installed in a spatial region having sufficient energy to excite the catalyst due to electrons and ions generated by the active irradiation means. This is preferable because the catalytic action can be efficiently extracted.
[0024]
As the means for generating electrons, corona discharge is the simplest. However, in order to prevent the discharge wire used in the means for generating electrons from being deteriorated by the atmospheric gas (especially oxygen or moisture), lower pressure is more advantageous. .
[0025]
As one specific use form, there is a use form in which the catalytic reaction device for decomposing and removing the discharge product is provided in and near the corona discharge unit in the image forming apparatus as described above. As another specific form of use, an apparatus for catalytic reaction that decomposes and removes gaseous harmful substances can be considered. In such an apparatus, in order to prevent abnormal discharge and short-circuit, it is preferable to include means for removing suspended dust, for example, removal means such as a filter.
Furthermore, when the catalytic reaction apparatus of the present invention is used for a slow reaction in which the adsorption reaction is rate-determining, the catalytic reaction occurrence part and the adsorption part are spatially functionally separated to periodically form the catalytic reaction occurrence part. It is preferable to adopt a configuration in which the catalyst layer moves.
[0026]
In many cases, the harmful gas component to be decomposed by oxidation-reduction has a concentration of ppm or ppb level, so it is more advantageous to concentrate and recover than processing at the concentration in the atmospheric state, By reducing the concentration, it is possible to prevent the efficiency from being reduced when processing under reduced pressure.
[0027]
Embodiment
Hereinafter, embodiments of the present invention will be described.
[0028]
Photocatalyst used in the present invention
Titanium oxide (TiO₂) Zinc oxide (ZnO₂) Cadmium oxide (CdO), tungsten trioxide (WO₃), Diiron trioxide (Fe₂O₈), Tin oxide (SnO)₂), Strontium titanate (SrTiO)₃), Zirconium oxide (ZrO)₂), And In₂O₃, Ag₂O, MnO₂, Cu₂O, V₂O₅Metal oxides such as cadmium sulfide (CdS), cadmium selenide (CdSe), zinc sulfide (ZnS), zinc selenide (ZnSe), and PbS, In₂S₃, Cu₂S, MoS₂, WS₂, Sb₂S₃, Bi₂S₃ZnCdS₂, WSe₂, HgSe, PbSe, CdTe, and other chalcogenide compounds.
In addition, metals and metal compounds such as silicon carbide (SiC), gallium arsenide (GaAs), gallium phosphide (GaP), silicon Si (n-type), and germanium Ge (n-type).
Among the above-mentioned catalysts, tin oxide (SnO) may be used as a material that is electrically conductive.₂), Indium oxide (In 2 O 8), and the like are preferable.
[0029]
Examples of the metal supported for improving the catalytic activity include transition metals such as iron, cobalt, nickel, copper, zinc, baradium, silver, platinum, and gold. The loading of these metals is said to be particularly effective in extracting a reduction reaction by electrons excited in the conduction band.
[0030]
Among the catalyst excitation methods, the most easily used method is an electron beam excitation method. However, since the electron beam has a negative charge, there is a problem that when the irradiation is continuously performed, the catalyst layer itself gradually has a negative potential, and the catalyst layer has conductivity as described above. Preferably it is.
[0031]
In addition, as a material well known as a transparent conductive film, zinc oxide (ZnO) is used for introducing impurities into the catalyst or for providing an excessive electron donating component as compared with an accurate stoichiometric ratio. Can be mentioned. Further, as the electron donating substance, it can be selected from elements of Group III of the periodic table having one valence higher than that of zinc, and Al is particularly suitable.
[0032]
The mixed Al is Al in the crystal lattice.³⁺Thus, electrons are emitted and donated into the film. In the case of zinc oxide, it is known that the conductivity of the film is increased by zinc atoms or oxygen vacancies contained in the crystal lattice. The concentration of the impurity level formed in this way is 10 as an effective component operating in the film.^-2-10^-4(Atom number ratio to the main component metal). Even if it does not originally have conductivity, the catalyst layer can be made conductive by this method.
[0033]
Furthermore, it is possible to impart conductivity even if the catalyst material is mixed with a group of materials exhibiting conductivity. The amount of conductive material to be mixed is SnO₂, In₂O₈ZnO or the like is preferably about 5 to 50% by weight. Alternatively, particulate carbon or metal may be mixed to provide conductivity. In the case of carbon or metal, the amount may be smaller than that of the conductive material, and the mixing amount is preferably 0.1 to 20% by weight. Also, the level of conductivity of the catalyst layer is required for antistatic applications.⁸Ω / □ or less, more preferably 10⁵-10⁶It is the surface resistivity at the level of Ω / □.
[0034]
Next, the catalytic reaction application apparatus will be specifically described.
In the discharge in the air, the electron generated from the corona wire has a very short mean free path in the air of 0.34 μm, and therefore the kinetic energy that the electron obtains from the electric field is estimated to be very small (for example, When the distance from the corona wire to the ground electrode is 10 mm and the applied voltage is 10 kV, the simple average electric field is 10⁶V / m, accelerated by a mean free path of 0.34 μm, and a kinetic energy of about 0.34 eV. [Calculated from kinetic energy of one electron (eV) = electric field strength (V / m) × travel distance (m). ]
[0035]
However, in reality, neutral molecules are ionized one after another due to the avalanche phenomenon. The minimum energy required to ionize each neutral molecule in the air is said to be 12.06 eV for oxygen molecules and 15.58 eV for nitrogen molecules. On the other hand, the bunt gap of the catalyst that seems to be effective according to the present invention is in the range of 0.3 to 5 eV. Therefore, as long as corona discharge is occurring, it is considered that there is sufficient energy to excite (or activate) the catalyst in the air by disposing it within the discharge range.
[0036]
Furthermore, in the application to general environmental purification technology, in most cases, the concentration of the reactant is a very small amount of mainly degradable harmful substances having a ppm or ppb level. Therefore, it is very inefficient if it is to be treated as it is in an atmospheric environment. Moreover, even if an attempt is made to concentrate and treat harmful substances, there is a problem that if they are excited with light energy, they cannot be treated at high concentrations under the excitation density of the catalyst. However, according to the present invention, instead of treating the concentration at the ppm level in the atmosphere, it is also possible to concentrate and separate the pollutants to a high concentration of harmful substances, and then perform the concentrated treatment in a reduced pressure. Also in terms of efficiency, the treatment at the ppm level in atmospheric pressure and 10^-4Since the amount of substance is almost equal to the treatment under reduced pressure at the Torr level, 10^-1-10^-3There is an advantage if it can be processed under reduced pressure at the Torr level.
Furthermore, it is desirable to install such a purification facility near the exhaust outlet of the high-concentration pollutant because the concentration / separation process is reduced.
[0037]
Next, the technical contents in the image forming apparatus of the present invention will be described. The current flowing through the shield by corona discharge is 10^-4-10^-6A level, the voltage applied to the shield is about 5-10 kV, the area inside the shield is about 2.8 cm²Since it is a value in the image forming apparatus apparatus Spiro7000 manufactured by Ricoh Co., Ltd., the irradiation energy on the shield surface is as follows.
(10^-4-10^-6A) × (5-10 × 10³V) /2.8cm²= 1.8 to 357 mVA / cm²
[0038]
Next, the excitation intensity required by the prior art will be described.
As an excitation energy (ultraviolet ray intensity) of a catalyst generally known as a photocatalyst, 1 μW / cm is used to bring out an antibacterial action.²Strength is required. This is a normal intensity level of room light. In removing harmful substances, for example, 1 ppm level of NO_XThe necessary UV intensity is 0.1 mW / cm²It is said that it is sufficient, which corresponds to the outdoors on a cloudy winter day. Also, the usual outdoor strength is 1mW / cm²On a sunny summer day, up to 4mW / cm²To reach.
Therefore, several mW / cm for excitation to derive the oxidation and reduction chemistry of the catalyst²Given the level of energy intensity, it would be applicable in many cases.
[0039]
In the case of the image forming apparatus calculated above, the range can be adjusted to be higher than the excitation energy level outlined in the prior art, and the redox product of the discharge product can be sufficiently oxidized. Furthermore, although the discharge current increases as the discharge current increases, the decomposition absorption efficiency does not change in the decomposition catalyst and filter used in the prior art and the capacity is saturated. The line excitation method has an advantage that the decomposition efficiency of the discharge product of the cracking catalyst increases because the number of reaction sites in the excited state increases as the excitation intensity increases. Therefore, there is an advantage that the setting range of the process can be expanded.
[0040]
Since the product after decomposition becomes gaseous oxygen when it is decomposed with respect to ozone, there is no particular problem. In the case of nitrogen oxides, NO on the catalyst surface₂Or HNO combined with moisture in the air₃Exist as a residue. In the case of nitrogen oxides, it is necessary to replace them periodically. However, it is possible to recycle it because it is possible to remove the pollutants by washing and drying enough to wash away with water.
[0041]
Further, a catalytic reaction application apparatus other than the image forming apparatus will be described. These devices correspond to air purifiers. The object of treatment according to the present invention is gaseous.
For example, a gaseous organic substance containing at least one element selected from carbon, hydrogen, oxygen, nitrogen, and sulfur, or a gaseous mixture containing the organic substance, or nitrogen, sulfur, and phosphorus An apparatus for catalytic reaction that decomposes and removes a gaseous substance comprising at least one selected from suboxides or oxides or a gaseous mixture containing the gaseous substance can be given.
[0042]
The catalytic reaction application apparatus as described above is a gaseous organic substance mainly composed of carbon, hydrogen, oxygen, nitrogen, sulfur or the like, or a gaseous substance composed of nitrogen, sulfur, phosphorus suboxides or oxides. Any one or a mixture thereof may be provided in a flow path in which the gaseous substance is decomposed and removed. In many cases, the substances in the previous period are off-flavors or irritating odors that are uncomfortable for humans, or are harmful to the human body and the environment.
[0043]
In addition to the gaseous harmful substances as described above, there are many solid substances such as house dusts such as dust and dust, fungi such as fungi, and insects. When using a discharge wire, there is a possibility of causing abnormal discharge or short-circuiting due to these airborne suspended matters. Although it may not be necessary in a very clean environment, it is preferable to provide a removing means such as a filter in order to prevent abnormal discharge or short-circuit due to floating substances in the atmosphere.
[0044]
In the apparatus described so far, it is assumed that a reaction occurs directly under the excitation means, but a slow reaction in which the adsorption reaction is rate-limiting can also occur. In the reaction in which the adsorption is rate-limiting, it is effective to take as wide an area as possible for the adsorption. Therefore, it is desirable that the catalytic reaction occurrence part and the adsorption part are functionally separated in time or space so that the catalyst layer periodically moves to the catalytic reaction occurrence part. For example, FIG. 5 shows a conceptual configuration diagram as an example of such a configuration. The shape is not limited to a cylindrical shape, may be a disk shape, may be a spiral shape, or may be partially cut so as to be replaceable. Further, it is possible to provide a means for detecting the concentration of the substance to be treated on the downstream side of the flow of the substance to be treated to control the moving speed of the substrate on which the catalyst layer is provided.
[0045]
【Example】
Examples of the present invention will be described below.
[0046]
Example 1
Acetaldehyde is removed by oxidation of catalyst surface by electron beam.
Anatase-type titanium oxide (specific surface area of about 300 m), a commercially available photocatalyst coating agent, on an aluminum plate having a width of 30 cm, a length of 5 cm, and a thickness of 1 mm²/ G) and carbon powder were mixed and applied to form a catalyst layer. The area resistance こ の of this catalyst layer is 2 × 10⁷Ω / □, and the film thickness was about 3 μm. A discharge wire serving as an electron emission source was installed 9 mm away from the catalyst layer to insulate it from the surroundings. The aluminum plate was connected to the ground, and the electrical component was assembled so that the electron emission source could be applied with a potential of −10 kV with respect to this ground. Next, a sealed case capable of shielding the light surrounding the portion other than the power supply portion of this apparatus so as to have a volume of 5 liters was made and filled with acetaldehyde to 250 ppm by concentration detection. After making these preparations, the power source of the electrical equipment was turned on to start discharging. After 20 minutes, the acetaldehyde concentration had dropped to 20 ppm.
[0047]
Example 2
Shield of corona charger of image forming device
Commercially available titanium oxide photocatalyst material containing an inorganic binder on the inner surface of the shield part of the corona charger of the image forming apparatus (for example, Tainok CA-62 or CRA-62 manufactured by Taki Chemical Co., Ltd.) is 0.3 to 0.5 μm. Coated with a thickness of. After being heat-treated and hardened, it was incorporated into an image forming apparatus.
Various conditions in the image forming apparatus were 7.8 mm at the shortest distance from the discharge wire and 125 mm at the farthest distance. The total area of the shield part is 2.8cm²It is. The voltage applied to the discharge wire, called the filament, is -5 to -10 kV with respect to the shield voltage or ground, and a rectangular current controlled at the both ends of the wire by a constant current type inverter power supply by a PWM (pulse width modulation) system for electron emission. A wave voltage is applied.
[0048]
When the surface potential of the OPC photoconductor was charged to -600 to -800 V, the current flowing through the photoconductor was several tens of μA, while the current flowing through the shield formed with the catalyst layer was several hundred μA. As an improvement effect of ozone decomposition / removal, the ozone concentration of the metal shield alone is 1.1 ppm as measured directly under the charger, whereas the ozone concentration when the catalyst is attached is detected in the range of 0.1-0.2 ppm. It was.
[0049]
In terms of appearance, when the number of copies reached from 230,000 to 250,000, discoloration was observed in the shield part, and it was dried and regenerated after washing with water. Nitrate ions were detected in the water used for washing with water, and the pH was slightly acidic at 6.0. The discoloration appears to be due to adsorption of nitrogen oxides. On the other hand, the regenerated parts could be used repeatedly as if they were new.
In the present embodiment, the example in which the catalyst layer is arranged in the shield part example is shown, but not limited to the shield part example, the range covered by electrons or ions having energy necessary for catalyst excitation, such as the grid part or the exhaust part of the charging device. If it is in.
[0050]
Example 3 (use for air purifier)
There is an air purifier as a device for purifying polluted air. Untreated air is introduced, suspended dust is first removed, harmful substances are decomposed with a catalyst, and then purified through a final filter. FIG. 3 shows a conceptual diagram after introduction of the atmosphere. As shown in FIG. 4, the catalytic reaction device portion was composed of an inner portion formed in a conical shape and a cylindrical outer portion so that the air flow was concentrated on the tube wall portion. The catalyst layer was formed on the inner surface of a cylindrical outer wall surface continuous with the conical portion and a tubular portion provided on the outer surface thereof. As a material for the catalyst layer, a mixture of zinc oxide, indium tin oxide and an inorganic hinder was formed on the wall surface by coating with a thickness of 0.3 μm, followed by heat treatment drying. The electron emission portion is fixed to the inner portion by an electrically insulated insulator, and is controlled by a power source (not shown).
[0051]
The introduced untreated gas is compressed into a part of the catalyst layer by the inner bell-shaped part of the inner case, proceeds along the flow path while hitting the wall surface where the catalyst layer is formed, and in the flow of the catalyst layer It is gradually decomposed by redox reaction. As a configuration, when the amount of floating dust is small, the configuration shown in FIG. 5 may be connected to a filter that removes floating dust and the like.
[0052]
In the catalytic reaction application apparatus in which the outer diameter of the inner cylinder formed with the catalyst layer is 30 cm, the inner diameter of the outer cylinder is 32 cm, and the length of the catalyst layer in the flow path direction is 50 cm, the flow rate is 8 liters / minute. A gas containing toluene at a concentration of 8 ppm was introduced. When the concentration of toluene was measured at the outlet of the catalyst layer reaction section, the concentration was reduced to 0.5 ppm. At this time, the voltage applied to the electron emission source was −15 kV, and the current flowing between the electron emission source and the catalyst layer was 1.2 mA.
[0053]
Example 4
In the catalyst reaction apparatus having the same shape as in Example 3, a catalyst having titanium oxide and activated carbon as main components and a coating agent by an inorganic binder is coated on the wall surface by the same area as in Example 3 so as to have a thickness of 0.5 μm. Dried to form. An oil rotary pump is connected to the exhaust port, and a solenoid valve is provided on the upstream side of the oil rotary pump.^-3The contact is provided with Toor and the solenoid valve is opened and closed.^-3The pressure was reduced so that it was maintained on the Toor table. A gas containing 50% by volume or more of nitrogen oxide was introduced into the reaction system at a flow rate of 1.5 cc / min using a reading meter in a reactor maintained in a depressurized state (in a normal atmosphere) Nitrogen oxide concentration is on the order of several ppm, so it is equivalent to being concentrated 10,000 times). Although the removal rate of nitrogen oxides is not much different from that in the case of treatment in the atmosphere, since the deterioration of the discharge wire is difficult to proceed, the wire replacement frequency is reduced to about 1/100.
[0054]
Example 5
In the case where the adsorption of the reactant to the catalyst layer is rate-limiting rather than the oxidation-reduction reaction, the excitation of the catalyst layer may be a point in the entire reaction, and it is desirable to take a large part that causes the adsorption reaction. For example, as shown in FIG. 6, the excitation part of the catalyst layer is a part of the rotation, and the other part is a part intended to adsorb the reactant. In such an apparatus, a detection part (not shown) for a substance to be reacted is provided on the downstream side of the flow path, and a feed hack is applied to the excitation conditions, the rotation speed of the drum coated with the catalyst layer, and the like. It is possible to process while optimizing the part.
[0055]
[Effects of the invention]
  In the case of simple adsorbents such as unexcited catalysts and activated carbon sheets of the prior art, there are problems such as a decrease in the decomposition effect of the catalyst due to the formation of a contaminated layer by atmospheric components and a decrease in the adsorption effect due to the adsorption saturation of contaminants I have a dotComparisonHowever, when a photocatalyst is used, the catalyst is activated during operation, so that there is an advantage that the effect of removing discharge products can be further improved and the effect can be sustained.
[0056]
Also, when maintenance is inspected when the effect is reduced, the conventional one is not recycled but discarded, whereas the photocatalyst can be washed with water to remove the adsorbed material and regenerate the catalyst, leading to resource saving.
[0057]
  Furthermore, in addition to the above-described effects, the invention of each claim can exhibit the following specific effects.
(1)There is provided an apparatus capable of causing catalysis even in a field where light cannot be used, as compared with a field of use limited to light of a photocatalyst.
(2)Since the catalyst layer has electrical conductivity, the layer itself is not charged up, and thus an apparatus capable of continuously producing a catalytic action is provided.
(3) An apparatus capable of decomposing and removing harmless substances that cause an unpleasant odor or irritating odor to the human body or cause deterioration of the global environment such as global warming when released into the atmosphere is provided.
(4) The discharge product can be decomposed and removed before diffusing out of the charger, and further, the catalyst is excited by the action of electrons or ions during discharge, so that the catalytic effect is always maintained in use. Further, even when an ozone decomposition filter is provided in the middle of the exhaust path, an apparatus is provided that can prolong the decomposition characteristics because the concentration when the filter is brought into the filter is low.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the principle of the present invention.
FIG. 2 is a diagram illustrating a configuration diagram when applied to a charger of an image forming apparatus.
FIG. 3 is a diagram illustrating a case where a catalytic reaction apparatus is incorporated in the middle of a flow path of a gas to be processed.
FIG. 4 is a diagram illustrating the internal structure of a catalytic reaction apparatus.
FIG. 5 is a diagram illustrating a partial cross-sectional view of a catalytic reaction apparatus incorporating a suspended dust filter.
FIG. 6 is a diagram illustrating a configuration of a catalytic reaction apparatus in which a catalyst or a layer containing a catalyst can periodically move with respect to an active irradiation means.

Claims (2)

Gaseous organic substances containing at least one element selected from carbon, hydrogen, oxygen, nitrogen and sulfur, or gaseous mixtures containing the organic substances, or nitrogen, sulfur and phosphorus An apparatus for catalytic reaction capable of decomposing and removing at least one gaseous substance selected from oxides or oxides or a gaseous mixture containing the gaseous substance, and (i) excited by light A catalyst having the property of causing chemical changes of oxidation and reduction, or a layer containing the catalyst, and means for exciting the catalyst with an electron beam , and (ii) a catalyst or means for exciting the catalyst An apparatus for catalytic reaction, wherein a layer containing a catalyst has conductivity and can move periodically. An image forming apparatus in which a corona discharge is used for charging a photosensitive member and a catalytic reaction device capable of decomposing and removing a discharge product in or near the corona discharge unit is provided. A catalyst having a property of being excited by light and causing a chemical change of oxidation and reduction, or a layer containing the catalyst, and a means for exciting the catalyst with an electron beam , and (ii) a means for exciting the catalyst On the other hand, the image forming apparatus is characterized in that the catalyst or the layer containing the catalyst has conductivity and can move periodically.

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