JPH05187623A - Catalytic reactor - Google Patents

Abstract

PURPOSE:To obtain a catalytic reactor by which a loss of radiation to the outside is made minimal, a heat in the catalyst reactor is used effectively, thereby a heat input for heating a catalyst is made the necessary minimum and a mixed gas of relatively low temperature constituted of an unburnt gas of fuel, a malodorant component, a harmful component, etc., and air is made to react smoothly to be odorless and harmless and exhausted. CONSTITUTION:A catalytic reactor has a construction wherein an outer passage 6 is formed by an outer wall 1 and an intermediate wall 2, an intermediate passage 7 is formed by the intermediate wall 2 and an inner wall 3, an inner passage 8 is formed inside the inner wall 3 and a catalyst 5 is disposed in the inner passage 8, and wherein a heater 4 is provided in the outer periphery of the catalyst 5 and a reaction gas is made to pass through the outer passage 6, the intermediate passage 7 and the inner passage 8 in this sequence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic reactor for reacting a mixed gas of a relatively low temperature composed of air such as fuel, malodorous components, harmful components, etc., and air, and exhausting them as odorless and harmless. Regarding

[0002]

2. Description of the Related Art A catalytic reactor that is a factory-scale large-scale one that oxidizes (with air) a small amount of pre-existing gas, harmful component gas, and malodorous component gas contained in combustion exhaust gas to make them harmless and odorless To small ones used as members of household appliances. And platinum as a catalyst,
A noble metal-based metal such as palladium, a heavy metal-based compound such as manganese, a perovskite-based complex oxide, or the like is used.
The catalyst is used in various shapes such as pellets, mats, nets, and honeycombs, but when handling gaseous reactants, honeycombs with low ventilation resistance and high mechanical strength are used. Is often used. However, these (oxidation) catalysts have low reactivity at room temperature, and it is necessary to set the reaction gas temperature or the catalyst temperature to about 200 ° C. or higher in order to effectively function (increase the reactivity) of the catalyst.

[0003]

When the reaction gas introduced into the catalyst can be set sufficiently higher than 200 ° C. such as combustion exhaust gas, it can be used as it is, but when it is not the reaction gas when passing through the catalyst. It is necessary to raise the temperature to 200 ° C. or higher with a heater such as a heater to enhance the catalytic reactivity. At this time, generally, a structure in which the entire outside is covered with a heat insulating material is often used in order to reduce the heat radiation loss at the time of heating, but by covering with the heat insulating material, the surface area is rather increased and the heat radiation loss increases. Often occurs. In addition, the catalytic reactor also becomes large.
In particular, when the catalyst itself is relatively small, heat loss becomes remarkable, and there is a problem that the required input for heating the catalyst becomes excessive. The present invention has been made to solve the above problems, and an object of the present invention is to provide a catalytic reactor having a compact structure in which the heat input for heating the catalyst is minimized.

[0004]

In order to solve the above problems, the present invention forms an outer passage with an outer wall and an inner wall, forms an inner passage with the inner wall and an inner wall, and forms an inner passage in the inner wall. Formed, the catalyst is placed in the passage thereof, and a heater is provided on the outer periphery of the catalyst,
The catalytic reactor is configured so that the reaction gas passes through the outer passage, the middle passage, and the inner passage in this order.

[0005]

When the reaction gas is introduced into the catalytic reactor having the above-mentioned structure according to the present invention, the reaction gas first enters the outermost passage which is the outermost passage of the reactor and then proceeds to the middle passage where it is heated by the heater. Then, the temperature reaches a temperature sufficient for the reaction, enters the inner passage, passes through the catalyst installed in the same portion, reacts, and is discharged to the outside. Since the main component of the reaction gas before introducing the catalytic reactor is air and the temperature is almost room temperature, when it is introduced into the outer passage, it forms an adiabatic layer of air with the outside world, and the heat inside the reactor is dissipated to the outside. It gets harder. Therefore, it is possible to eliminate the specifications of the heat insulating material and the like. At this time, a part of the heat is transferred to the reaction gas mainly composed of air, but since the reaction gas thereafter enters the middle passage and is heated, the transferred heat is used for preheating the reaction gas. Also, since the heater is installed around the catalyst in the middle passage, it heats the reaction gas before passing through the catalyst and also heats the catalyst from the outside, so that the catalytic reaction in the same part can proceed smoothly. Becomes Further, the heat of the exhaust gas after passing through the catalyst is recovered by the reaction gas introduced into the intermediate passage through the inner wall and used for preheating the reaction gas. In this way, the heat emitted from the heater is effectively utilized for the catalytic reaction, and the heat dissipation loss to the outside can be extremely reduced.

[0006]

FIG. 1 is a vertical sectional view of an embodiment according to the present invention. Reference numeral 1 is an outer wall, 2 is an inner wall, and 3 is an inner wall. The outer wall 1 and the inner wall 2 form an outer passage 6, the inner wall 2 and the inner wall 3 form a middle passage 6, and the inner wall 3 The passage 8 is formed. Each wall is made of a stainless steel plate which is a heat resistant metal, but when it is used as a high temperature reactor, it may be made of a ceramic plate or the like. A catalyst 5 in which a precious metal-based metal is carried on a honeycomb-shaped (monolith) carrier is installed in the inner passage 8. In addition to this, the catalyst 5 may have various shapes such as a pellet shape and a mat shape. Reference numeral 4 denotes a heater, and here, a surface insulating type electric heater formed in a cylindrical shape so as to be housed on the outer periphery of the inner wall 3 holding the catalyst 5 is used. The heater 4 is provided so as to be in direct contact with the inside of the inner wall 3 and the outer periphery of the catalyst 5, and the middle passage 6 is provided through the inner wall 3.
It is also possible to heat the reaction gas passing through it. In the former configuration, fins may be provided on the outer peripheral portion of the heater, and in the latter configuration, fins may be provided on the outer side of the inner wall 3 for promoting heat transfer to the reaction gas. Reference numeral 9 is a reaction gas inlet, and 10 is an exhaust gas outlet. 12 is a plurality of passages 1
Reference numeral 11 is an air chamber having 2a, and 11 is a temperature detector for detecting the reaction gas temperature and controlling the heater input. 1
3 is an adiabatic seat. The arrows in the figure indicate the flow of the reaction gas.

It is introduced into the catalytic reactor through the reaction gas inlet 9 in which the component gas and the air are mixed, and enters the outer passage 6 through the passage 12a of the air chamber 12. The reaction gas passing through the outer passage 6 is slightly preheated by the heat transmitted from the inside through the inner wall 2 and forms an air heat insulating layer by itself to prevent heat dissipation from the outer wall 1 to the outside. After that, the reaction gas proceeds to the inner passage, recovers heat from the downstream side of the catalyst through the inner wall 3, and is further preheated. The heat recovery is further promoted by attaching fins for promoting heat transfer to the inner and outer surfaces of the inner wall 3.
Next, the reaction gas is heated to a predetermined temperature by contacting a heater provided in the middle passage 7, and further passes through the catalyst in the inner passage 8. At this time, an oxidation reaction is performed on the surface of the catalyst 5, and the gas is converted into oxides such as carbon dioxide and water. The exhaust gas after passing the catalyst 5 transfers heat to the reaction gas passing through the intermediate passage 7 through the inner wall 3 on the downstream side thereof, and the exhaust gas is cooled to a low temperature and discharged from the exhaust gas outlet 10 to the outside of the device. The input of the heater 4 is controlled by monitoring the temperature of the temperature detector 11, so that the temperature of the reaction gas is appropriately maintained and the reaction proceeds smoothly. The catalytic oxidation reaction temperature is usually about 200 to 800.
It is appropriate to set the temperature within the range of ° C, but it is necessary to set it flexibly according to the type of reaction gas. According to this example, when the catalyst inlet temperature was set to 500 ° C., carbon monoxide gas was mixed at a concentration of 0.1% in air to form a reaction gas, and the catalyst was passed at a flow rate of 20 NL / min. The heating efficiency of the heater 4 (= heater input / theoretical required heating amount × 100) was about 90%. In this way, the heat of the heater 4 can be used very effectively to allow the reaction to proceed, and the heat dissipation effect to the air can also minimize the heat dissipation loss to the outside.
Further, since the structure is simple and a heat insulating material is not required, it is compact and can be manufactured at low cost. As a matter of course, the mounting direction of the catalytic reactor can be set freely, so it is easy to use. Therefore, it can be used for a wide range of purposes such as purification of gas in the combustion exhaust gas having a relatively low temperature and purification of offensive odors generated from various devices.

[0008]

EFFECTS OF THE INVENTION The present invention has the above-described structure, which minimizes heat radiation loss to the outside and enables effective use of heat in the catalytic reactor, thereby minimizing the heat input for heating the catalyst. It is possible to provide a container. Moreover, the structure is simple and compact, and it is possible to manufacture at low cost. Also, the mounting direction is free,
Since it is easy to use, it can be used for a wide range of purposes, such as purification of gases from combustion exhaust gas having a relatively low temperature, purification of offensive odors generated from various devices, and the like.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment according to the present invention.

[Explanation of symbols]

 1 outer wall 2 middle wall 3 inner wall 4 heater 5 catalyst 6 outer passage 7 middle passage 8 inner passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Suzuki, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. An outer passage is formed by an outer wall and an inner wall, a middle passage is formed by the inner wall and an inner wall, an inner passage is formed in the inner wall, and a catalyst is arranged in the inner passage. A catalytic reactor in which a heater is provided on the outer periphery of the catalyst and a reaction gas is passed from the outer passage to the middle passage and then the inner passage in this order.