JPH0739722A - Method and apparatus for purification of exhaust gas - Google Patents

Abstract

PURPOSE:To surely eliminate hazardous ingredients and odoral ingredients in an exhaust gas without requiring a complicated constitution of an apparatus. CONSTITUTION:A flow path 6 for adsorption and a flow path 7 for oxidation are arranged in the opposite direction and in being neighbor to each other and a plurality of units wherein an adsorbent layer 2 and an oxidation catalyst layer 3 are provided on a sheet of electrode element 12 are assembled and this is arranged in the flow path 6 for adsorption so as to be the adsorbent layer 2 and in the flow path 7 for oxidation so as to be the oxidation catalyst layer 3 to adsorb hazardous ingredients and odoral ingredients in an exhaust gas on the adsorbent and adsorbed ingredients are eliminated by heating the element and oxidative treatment can be performed with the oxidation catalyst. It is possible thereby to surely eliminate the hazardous and odoral ingredients by means of a simple constitution of an apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to exhaust gas purification for removing combustible harmful and malodorous components such as hydrocarbons, carbon monoxide, and odorous gases in exhaust gas discharged from various industries and chemical plants. A method and its apparatus.

[0002]

2. Description of the Related Art In the manufacturing and processing industry of various organic substances represented by resin manufacturing and processing, the exhaust gas from the factory may contain a trace amount of a component causing a bad odor and a component harmful to the human body. It is desired to remove these from the viewpoint of pollution prevention. Various efforts have been made for the treatment of such exhaust gas, but when the amount of the harmful and malodorous components contained in the exhaust gas becomes extremely small, it becomes difficult to treat them, and the conventional technique treats them. Some things are not available.

In the method adopted as the above treatment method, the exhaust gas is introduced into a combustion furnace and is burned to oxidize the harmful and malodorous components (hereinafter referred to as the direct combustion method), and the oxidation catalyst is used as the above-mentioned method. There is a method (hereinafter referred to as a catalytic combustion method) of treating harmful and malodorous components by catalytically oxidizing them. In particular, the catalytic combustion method is regarded as a preferable method because it suppresses the generation of nitrogen oxides, which is a source of pollution. In addition to this, as a method generally used, there is a method (hereinafter, referred to as a simple adsorption method) of adsorbing harmful and malodorous components by passing exhaust gas through an adsorbent such as activated carbon.

When treating a gas in which the amount of harmful or malodorous components contained in the exhaust gas is extremely small, a method combining a simple adsorption method and a direct combustion method or a catalytic combustion method, that is, a harmful or malodorous component once in the exhaust gas Is adsorbed on the adsorbent, and when the amount of adsorption reaches a certain level, a high-temperature gas is blown to desorb the adsorbed components, and the mixture is directly incinerated or oxidized by an oxidation catalyst (hereinafter referred to as adsorption-oxidation treatment method). Is also widely used.

[0005]

The present invention is an apparatus using the adsorption-oxidation treatment method among the above-mentioned various methods, but the conventional apparatus has the following problems.

When desorbing harmful and malodorous components that have once been adsorbed, the adsorbent is heated to a temperature of 100 to 500 ° C., so that some heat source is required. In the conventional technology, since the auxiliary burner burns the fuel to heat it,
Extra fuel for the auxiliary burner is required, and the control system for operating the auxiliary burner is complicated. Also, by making the adsorbent layer rotatable and adsorbing it only in a certain area of the adsorbent layer, the rotor of the adsorbent layer is rotated when adsorption has progressed to some extent, and the new adsorbent layer part is exposed to exhaust gas while adsorbing the adsorbent layer. In the method of desorbing the hot gas by passing it through the part of the adsorbent layer in which the adsorbent layer has been completed, the adsorbent layer may be deformed or damaged due to the change in the temperature distribution generated during the rotation of the rotor. Furthermore, since the rotating part is required, the device configuration becomes complicated, and the cost of the device increases.

An object of the present invention is to reliably remove harmful and malodorous components of exhaust gas with a simple device structure.

[0008]

Means for Solving the Problems The above-mentioned problems are solved by introducing a gas containing exhaust gas from an intake port into a gas flow path connected to the intake port, and introducing harmful or odorous components contained in the taken gas into the gas flow path. Adsorbed to the adsorbent layer disposed in, and if necessary or periodically heated the adsorbent layer to desorb the harmful and malodorous components that have been adsorbed, desorbed harmful,
The malodorous component was oxidized by the oxidation catalyst layer disposed in the gas flow channel downstream of the adsorbent layer, and the harmful and malodorous component-removed gas was disposed further downstream in the gas flow channel of the oxidation catalyst layer. In the method for purifying exhaust gas discharged from the discharge port, an adsorbent layer and an oxidation catalyst layer are formed in separate regions on a continuous metal plate-shaped substrate, and the continuous substrate is provided with the oxidation catalyst layer downstream of the adsorbent layer. This is achieved by a method of arranging the adsorbent layer and the oxidation catalyst layer so that the temperature of the adsorbent layer is higher than that of the adsorbent layer and the oxidation catalyst layer.

The above-mentioned problem is further solved by an intake port for taking in a gas containing exhaust gas, a gas flow path connected to the intake port, and a harmful or malodorous component contained in the gas introduced in the gas flow path. An adsorbent layer for adsorbing the adsorbent, an oxidation catalyst layer disposed in a gas flow path on the downstream side of the adsorbent layer for oxidizing and removing harmful and malodorous components desorbed from the adsorbent layer by heating the adsorbent layer, and the oxidation In an exhaust gas treatment device including a discharge port for discharging a gas in which a harmful and malodorous component is separated and removed, which is arranged in a gas flow path on the downstream side of a catalyst layer, the adsorbent layer and the oxidation catalyst layer are made of a continuous metal. The adsorbent layer and / or the oxidation catalyst layer are formed in different regions of the plate-shaped substrate, and the adsorbent layer and / or the oxidation catalyst layer are formed in the middle part between the region where the adsorbent layer is formed and the region where the oxidation catalyst layer is formed. Electric current is applied to the board edges facing each other. Electrodes are provided for the substrate, and the substrate is arranged so that the adsorbent layer and the oxidation catalyst layer are located in the gas flow path and the adsorbent layer is on the upstream side of the oxidation catalyst layer. To be done.

[0010]

When a gas containing harmful and malodorous components is taken in through the suction port, the gas passes through the adsorbent layer on the substrate having the electrode. At this time, harmful and malodorous components of the gas are adsorbed by the adsorbent. When the adsorbed amount reaches a certain level, the adsorbent layer on the substrate having the electrode is adsorbed because the adsorbent layer on the substrate having the electrode is heated by energizing and heating the electrode at the intermediate portion of the substrate having the electrode and the end portion on the adsorbent layer side. The desorbed component is desorbed, and the desorbed component flows to the oxidation catalyst layer, where it is oxidized by the catalyst of the oxidation catalyst layer which is heated together with the adsorbent layer by heat conduction of the substrate. Then, the treated gas is discharged to the outside of the device through the discharge port.

[0011]

FIG. 1 shows an embodiment of the present invention. The exhaust gas purifying apparatus 1 is arranged adjacent to each other so that the exhaust gas flow directions are opposite to each other, and the adsorption flow path 6 and the oxidation flow path 7 each include an inlet 14 and an outlet 15. And a substrate having electrodes (hereinafter, electrode element 1
2) are combined so that the surfaces formed by the adsorbent layer 2 and the oxidation catalyst layer 3 are parallel to the flow direction of the exhaust gas. 7 and a gap 13 connecting the adsorption flow path 6 and the oxidation flow path 7.

The electrode element 12 is a substrate made of metal and has an electrode lead-out portion 4A connected to each electrode and a lead wire 4 connected to the electrode lead-out portion 4A. As shown in FIG. 4, an electrode joint portion 10 and an electrode fixing hole or notch 11 are provided in the intermediate portion and both end portions of the surface of the electrode element 12, respectively.
The adsorbent layer 2 is formed on one half of the surface and the oxidation catalyst layer 3 is formed on the other half. Further, as shown in FIGS. 2 and 3, the plurality of electrode elements 12 are combined with each other by using the electrode fixing material 8 so as to couple the intermediate electrode 5 and the end electrode 4B. The combined electrode elements are arranged such that the adsorbent layer portion thereof is located in the adsorption flow channel 6 and the oxidation catalyst layer portion thereof is located in the oxidation flow passage 7, and the adsorbent layer side end portion of the electrode element is disposed. The oxidation catalyst layer side end is attached to the wall surface of the flow path via an inorganic seal material 9 which also functions as an electrical insulating material and serves as a thermal expansion absorber. Further, the intermediate electrode 5 blocks the partition between the adsorption flow channel 6 and the oxidation flow channel 7 in the portion where the combined electrode elements are attached.

After passing through the adsorbent layer 2 in the adsorption channel 6, the exhaust gas flow is reversed in the gap 13, passes through the oxidation catalyst layer 3 in the oxidation channel 7, and is discharged to the outside of the apparatus. To be done. In this process, since the electrode element is not normally energized, harmful and malodorous components in the exhaust gas are adsorbed by the adsorbent layer 2. When the harmful and malodorous components are adsorbed to the adsorbent layer 2 to some extent and the adsorbing effect of the adsorbent layer 2 is lost, the electrode element is energized and the electrode element is heated.
The components adsorbed on the adsorbent layer 2 are desorbed, and the desorbed components flow to the oxidation catalyst layer 3 where they are oxidized.

The energization can be performed by separating the adsorbent layer 2 and the oxidation catalyst layer 3 through the intermediate electrode 5. Therefore, if it becomes necessary to heat only one side of the adsorbent layer 2 or the oxidation catalyst layer 3, by energizing only one side,
The purpose of heating the electrode element is reached. In this embodiment, both the adsorbent layer 2 and the oxidation catalyst layer 3 are configured to be able to conduct electricity, but the adsorbent layer 2 and the oxidation catalyst layer 3 are integrated as an electrode element, and the adsorbent layer 2 and Since the substrate of the oxidation catalyst layer 3 is a metal, the heat conduction is good. Therefore, if one of them is energized and heated, the other also generates heat by heat conduction. This is a major feature of this embodiment, and the heat required for operating the device can be utilized very effectively.

The form of energization (the amount of energization, the interval of energization, etc.) changes variously depending on the capacity of the apparatus and the amount and type of exhaust gas to be treated, but the desorption and oxidation of harmful and malodorous components in the exhaust gas can be most effectively performed. It may be set so as to meet the conditions.

When the electrode element is directly fixed to the flow path, the electrode element heated by the energization is
Deforms due to thermal expansion. In order to prevent this, in this embodiment, an inorganic sealing material 9 having a low density is arranged between both ends of the electrode element and the flow path so as to serve as both electrical insulation and absorption of thermal expansion.

The electrode element made of a metal substrate, which is one of the basic constitutions of this embodiment, may be basically any element as long as it can attach the adsorbent and the oxidation catalyst. However, in order to effectively perform the adsorption in a small space, it is desirable that the adsorbent can support as much amount as possible. On the other hand, in the oxidation catalyst portion, it is necessary to increase the contact efficiency in order to promote the oxidation reaction. In consideration of such a point, in this embodiment, the metal substrate of the electrode element is made of expanded metal. However, the type of metal used for the metal substrate, the size and shape for making the electric resistance thereof to a predetermined value, the number of electrode elements, and the like are selected according to the capacity of the device. Further, if an appropriate electrode element is used, exhaust gas treatment can be performed reliably regardless of the amount of exhaust gas.

The procedure for producing the adsorbent layer of the electrode element is as follows. First, a small amount of an appropriate binder or additive is added to the raw material of the adsorbent and kneaded to obtain a paste having an appropriate consistency. Next, the paste is applied to the expanded metal using a spatula or a roll. In order to prevent the adsorbent layer from peeling off from the expanded metal, an appropriate amount of inorganic fiber or inorganic plate-like material having an appropriate size may be added to the paste. These are commonly used techniques. In this way, the adsorbent layer 2 carrying a large amount of adsorbent is obtained.

On the other hand, the oxidation catalyst layer 3 can be formed by the same method. FIG. 4 schematically shows the electrode element thus obtained, in which the metal used as the substrate is slightly exposed on the element surface. In the region of the electrode joint portion 10 shown in FIGS. 4 and 5, an adsorbent and an oxidation catalyst are not applied to join the intermediate electrode 5 and the end electrode 4B, and a hole for fixing the electrode is further provided. Alternatively, a notch 11 is provided. As for the oxidation catalyst layer 3A of the element shown in FIG. 5 with respect to FIG. 4, the oxidation catalyst is not applied in a paste form,
The oxidation catalyst portion is dipped in a slurry made of a catalyst raw material to remove the excess slurry so that the expanded metal mesh is not crushed. This is because in the case of an oxidation catalyst, not only the amount of the oxidation catalyst itself but also the degree of contact between the treatment gas and the catalyst is important, and the three-dimensional structure peculiar to expanded metal is effective in improving the contact efficiency between the catalyst component and the treatment gas. Because there is. However, in practical use, which of the oxidation catalyst layers 3 and 3A is selected depends on the content of the processing gas and the performance of the oxidation catalyst.

Although the areas of the adsorbent layer 2 and the oxidation catalyst layer 3 or 3A are made substantially equal in FIGS. 4 and 5, the area ratio may be changed according to various conditions.

[0021]

According to the present invention, the structure of the exhaust gas purifying device is simplified, the design is facilitated, and the cost of the device is reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of an exhaust gas purifying apparatus of the present invention.

FIG. 2 is a perspective view of a combined electrode element of an embodiment of an exhaust gas purifying apparatus of the present invention.

FIG. 3 shows an exhaust gas purifying apparatus of the embodiment shown in FIG. 1 of the present invention.
It is a sectional view taken along the line III-III.

FIG. 4 is an elevational view of an electrode element of an embodiment of the exhaust gas purifying apparatus of the present invention.

FIG. 5 is an elevational view of another example of the electrode element of the embodiment of the exhaust gas purifying apparatus of the present invention.

[Explanation of symbols]

 1 Exhaust Gas Purification Device 2 Adsorbent Layer 3 Oxidation Catalyst Layer 3A Oxidation Catalyst Layer 4 Lead Wire 4A Electrode Extraction Part 4B End Electrode 5 Intermediate Electrode 6 Adsorption Flow Path 7 Oxidation Flow Path 8 Electrode Fixing Material 9 Inorganic Sealing Material 10 Electrode Joint part 11 Fixing hole or notch 12 Electrode element 13 Gap 14 Suction port 15 Discharge port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B01D 53/81 53/94 B01D 53/36 103 Z

Claims (3)

[Claims] 1. A gas containing exhaust gas is introduced from an inlet into a gas passage connected to the inlet, and harmful and malodorous components contained in the introduced gas are adsorbed in an adsorbent layer arranged in the gas passage. The adsorbent layer is adsorbed and the adsorbent layer is heated as necessary or periodically to desorb the adsorbed harmful and malodorous components, and the desorbed harmful and malodorous components are separated from the adsorbent layer on the downstream side gas. In the exhaust gas purification method, the oxidation treatment is carried out in the oxidation catalyst layer arranged in the flow path, and the harmful and malodorous components are discharged from the discharge port arranged on the gas flow path downstream side of the oxidation catalyst layer, An adsorbent layer and an oxidation catalyst layer are formed in separate regions on a continuous metal plate-shaped substrate, and the continuous substrate is placed in the gas flow path so that the oxidation catalyst layer is on the downstream side of the adsorbent layer. And heat either the adsorbent layer or the oxidation catalyst layer. The exhaust gas purifying method is characterized in that the temperature of the other is raised by doing so. 2. A suction port for taking in a gas containing exhaust gas, a gas flow channel connected to the suction port, and an adsorption for adsorbing harmful and malodorous components contained in the gas taken in and arranged in the gas flow channel. An agent layer, an oxidation catalyst layer disposed in a gas flow path on the downstream side of the adsorbent layer for oxidizing and removing harmful and malodorous components desorbed from the adsorbent layer by heating the adsorbent layer, and a downstream of the oxidation catalyst layer In an exhaust gas treatment device including a discharge port for discharging a gas in which harmful and malodorous components are separated and removed, which is disposed in a side gas flow path, a metal plate-shaped substrate in which the adsorbent layer and the oxidation catalyst layer are continuous Formed in different regions of the substrate and facing the intermediate portion of the region where the adsorbent layer of the substrate is formed and the region where the oxidation catalyst layer is formed, and to face the intermediate portion with the adsorbent layer and / or the oxidation catalyst layer interposed therebetween. Electrodes are provided on the edge of the substrate The exhaust gas purifying apparatus is characterized in that the substrate is arranged such that the adsorbent layer and the oxidation catalyst layer are respectively located in the gas flow path and the adsorbent layer is on the upstream side of the oxidation catalyst layer. . 3. The exhaust gas purifying apparatus according to claim 2, wherein the metal plate-shaped substrate is an expanded metal.