JPS62201631A - Treatment of gas containing combustible component - Google Patents

Abstract

PURPOSE:To stably treat a gas contg. combustible components for a long period by passing the gas through a rotary regenerative heat-exchange body to heat the gas, then bringing the gas into contact with an oxidation catalyst, and bringing the gas further heated by the oxidation heat again into contact with the oxidation catalyst to regeneration the catalyst. CONSTITUTION:The exhaust gas contg. combustible components such as solvent and CO is passed through a heat receiving fluid-side passage A of a heat accumulating body 36 which is formed into a honeycomb structure and can be freely rotated, and heated. The gas is then passed through the inlet-side oxidation catalyst 39 and the combustibles are mostly oxidized. The exhaust gas heated by the oxidation heat is reversed in a header 40 and passed through the outlet- side oxidation catalyst. The SO2, etc., deposited on the catalyst are desorbed, and the catalyst is regenerated. The gas is passed through the heat radiating fluid-side passage to heat the heat accumulating body. Besides, the heat receiving side and the heat radiating side are successively alternated by the rotation of a rotating shaft 34, and the leakage of the fluid is prevented by a partition structure 38.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a method for treating gases containing combustible components, such as carbon oxides.

"Prior Art and its Problems" Exhaust gas containing flammable components derived from solvents such as toluene, xylene, alcohols, and cellosolves is emitted from automobile paint drying processes or steel plate paint drying ovens. In addition, exhaust gas containing carbon monoxide is emitted from iron ore sintering furnaces. Such gases containing flammable components at a concentration of at most several percent or less, or in some cases less than 1%, must be treated after the combustible components they contain are treated to prevent air pollution or from the viewpoint of health and safety. must be released into the atmosphere.

Conventionally, methods for treating these gases containing flammable components include a method in which the gas is heated to a high temperature using a burner or the like to combust the combustible components, and a method in which the gas is brought into contact with an oxidation catalyst to oxidize the combustible components. It has been adopted.

However, in the former case, it is necessary to heat the gas to about 600 to 800 degrees Celsius and to allow a certain amount of residence time, which has the disadvantage of requiring a large-scale heat-resistant structure and consuming a large amount of thermal energy. .

On the other hand, the latter gas can be processed at lower temperatures, which simplifies the equipment and consumes less energy. However, in addition to the flammable components mentioned above, the gas also contains SOx, tar, etc. It also often includes S
Ox, tar, and the like adhere to the catalyst and reduce the activity of the catalyst, making it difficult to stably process combustible components. Another problem is that the temperature of the gas is too low compared to the activation temperature of the oxidation catalyst, so that combustible components can only be treated insufficiently or at all.

``Object of the Invention'' The object of the present invention is to provide a combustible component that can be stably treated over a long period of time without reducing the activity of the oxidation catalyst when oxidizing gas containing flammable components using an oxidation catalyst. It is an object of the present invention to provide a method for treating gas containing gas, and furthermore, to provide a treatment method that allows the above-mentioned treatment using an oxidation catalyst even if the gas containing combustible components is at a low temperature.

"Summary of the Invention" The method for treating gas containing flammable components according to the present invention involves passing the gas containing combustible components through the heat-receiving fluid side flow path of a rotary regenerative heat exchanger to raise the temperature to a temperature equal to or higher than the activation temperature of the oxidation catalyst. oxidize the combustible component by bringing it into contact with an oxidation catalyst in that state, further increasing the temperature of the gas by the heat of oxidation, and regenerating the oxidation catalyst by bringing the gas into contact with the oxidation catalyst again, Furthermore, it is characterized in that it is taken out through a heat radiation fluid side flow path of the rotary regenerative heat exchanger.

In this way, the combustible component-containing gas is passed through the receiver of the rotary regenerative heat exchanger and the S fluid side flow path to reach a temperature higher than the activation temperature of the oxidation catalyst before being brought into contact with the oxidation catalyst. It exhibits its activity and can effectively oxidize combustible components such as carbon oxide, hydrocarbons, and oxygen-containing organic solvents. Then, the temperature of the gas is further raised by the heat of oxidation of the combustible components, and this gas is brought into contact with the oxidation catalyst again, so that the sow, tar, etc. contained in the gas containing the combustible components are transferred to the catalyst. Even if the activity of the catalyst decreases due to adhesion, the catalyst can be regenerated by removing the SOX, tar, etc. by vaporization or the like.

Furthermore, since this high-temperature gas is passed through the heat radiation fluid side flow path of the rotary regenerative heat exchanger, it can be used to heat the single-rotary regenerative heat exchanger and preheat the combustible component-containing gas. .

In a preferred embodiment of the invention, as an oxidation catalyst.

The active species used is one or more selected from Ru, Rh, Pd and Pt. A catalyst having such active species can be easily regenerated by raising the temperature to a high temperature even if the catalyst activity decreases due to adsorption of SOX, tar, etc. in the gas.

According to another preferred embodiment of the present invention, a combustible component is further added to the combustible component-containing gas for treatment. In other words, in order to regenerate the catalyst, it is necessary to raise the temperature of the gas above the regeneration temperature of the oxidation catalyst using the heat of oxidation of the combustible components, and to bring this gas into contact with the oxidizer V again. When the amount of combustible components used is small, sufficient oxidation heat cannot be obtained, and it may be difficult to raise the temperature of the gas above the regeneration temperature of the oxidation catalyst. In such a case, by adding a flammable component such as propane in advance and treating the gas, the temperature of the gas can be raised to the above-mentioned regeneration temperature or higher.

"Embodiments of the Invention" Examples of the present invention will be described in detail below with reference to the drawings.

1 and 2 illustrate an example of a rotary regenerative heat exchanger for implementing the present invention.

In FIGS. 1 and 2, 31 is a cylindrical casing with a closed bottom and has a fluid inlet 32 and a fluid outlet 33 in the upper part. A rotating shaft 34 is inserted through the axial center of the casing 31 and is rotatably supported by a support mechanism 35 at the bottom.

Inside the casing 31, a heat storage body 36 is arranged as a rotary regenerative heat exchange body, leaving a space functioning as a header 40 at the bottom. That is, the heat storage body 36 is formed of a material having heat resistance and heat storage properties such as ceramics or metal in a honeycomb shape, a wire mesh laminate shape, a three-dimensional mesh shape, etc., and has a large cylindrical shape as a whole, and from a macroscopic perspective, Fluid is allowed to flow through the heat storage body 36 parallel to the rotating shaft 34 .

The heat storage body 36 is pivotally attached to the rotation shaft 34 so as to be rotatable integrally with the rotation shaft 34, and is rotated by a rotation transmission device 37 installed outside the casing 31. Heat storage body 3
In the rotation path 6, A, that is, the part that directly communicates with the fluid population 32 is the heat-receiving fluid side flow path, and B, that is, the part that directly communicates with the fluid outlet 33.
The part that directly communicates with is the heat dissipation fluid side flow path. Therefore, in the heat storage body 36, the heat receiving fluid side flow path and the heat dissipation fluid side flow path are sequentially and relatively alternately replaced by the rotation thereof.

Note that the gap between the outer periphery of the heat storage body 3B and the inner periphery of the casing 31 is sealed by an appropriate method to prevent fluid from flowing. A partition structure 38 is provided in the upper part of the casing 31 between the fluid port 32 and the fluid outlet 33 .

A sealing structure is provided that prevents the fluid in the fluid port 32 and the fluid in the fluid outlet 33 from coming into contact with each other.

Further, an oxidation catalyst 38 containing platinum as an active species is supported on the lower end surface of the heat storage body 3B. Therefore, the oxidation catalyst 3
9 rotates around the rotating shaft 34 together with the heat storage body 36 . This oxidation catalyst 39 is.

When the fluid is exhaust gas with a predetermined CO concentration, the C in the exhaust gas
This is to oxidize and remove O and release heat of CO oxidation. Further, a space is formed between the oxidation catalyst 38 and the bottom of the casing 31, and a header 40 that reverses the flow path of the fluid is provided.
It becomes.

Next, an embodiment of the present invention using the above heat exchanger will be described. Now, from the fluid inlet 32, the CO concentration is 3% and the temperature is 150.
We will flow exhaust gas at ℃. Note that this exhaust gas contains SOx at a concentration of about 1100 pp. Since the temperature of this exhaust gas is too low, almost no catalytic reaction occurs even if it is brought into direct contact with the oxidation catalyst 39 at this temperature.
The CO is essentially not oxidized at all.

Therefore, in the present invention, the exhaust gas is first passed through the heat-receiving fluid side flow path A of the heat storage body 36 and heated, and at the outlet thereof, the exhaust gas is heated.
After being heated to 0° C., it passes through an oxidation catalyst 39 on the inlet side. In this way, the exhaust gas is heated to 300°C, which is higher than the activation temperature of the oxidation catalyst, and then passes through the oxidation catalyst 3B on the inlet side, so most of the CO in the exhaust gas is oxidized.
Oxidation heat is released. As a result, the exhaust gas is
The temperature is 480° C. when it is reversed inside and passes through the oxidation catalyst 38 on the exit side again. Note that the oxidation catalyst 38 on the inlet side is chemically poisoned by SOx and its activity is reduced. And the oxidation catalyst 38 on the outlet side.

It is regenerated by contacting exhaust gas heated to 480°C. That is, SOx attached to the fermentation catalyst 3B on the inlet side
is desorbed and removed from the catalyst.

The exhaust gas further passes through the heat radiation fluid side flow path B of the heat storage body 36 and heats the heat storage body 3B. This heat causes the heat storage body 36
When this part rotates and becomes the heat-receiving fluid side flow path A, the exhaust gas can be preheated. At the fluid outlet 33, the exhaust gas temperature is 380° C. and the GO concentration is 0.5%. In order to regenerate the oxidation catalyst 39 sufficiently and reliably, it is necessary to turn it over at the header 40 and regenerate the oxidation catalyst 39 on the outlet side.
It is preferable that the gas temperature at the time of contact with 9 is 440° C. or higher.

Next, another embodiment of the present invention using the above heat exchanger will be described. This time, exhaust gas with a CO concentration of 0.5% and a temperature of 150° C. will be used. In addition, the exhaust gas contains W degrees to
It contains about opp-level of SOx. In the case of this exhaust gas, it is expected that sufficient GO oxidation heat will not be obtained due to the low CO concentration. Therefore, 0.3% propane is added to the exhaust gas in advance. In this way, when the exhaust gas to which propane has been added flows from the fluid port 32, the exhaust gas is transferred to the heat storage body 3B.
When passing through the heat-receiving fluid side flow path A, it is heated to 300°C.
CO and propane are oxidized through the oxidation catalyst 39 on the inlet side. This generates oxidation heat and raises the temperature of the exhaust gas to 480°C. Furthermore, the exhaust gas is reversed by the header 40 and the oxidation catalyst 3 on the outlet side
9. The oxidation catalyst 38 on the exit side comes into contact with the exhaust gas heated to 480° C., removes attached SOx, and is regenerated. The exhaust gas further passes through the S-fluid side flow path B of the heat storage body 36 and heats the heat storage body 36 . At the fluid outlet 33, the exhaust gas temperature is 380°C, 0.05°C 0.04%,
The propane concentration is 0.02%.

In the above embodiment, a case is shown in which the heat storage body 36 and the oxidation catalyst 38 interlocked with the heat storage body 36 are continuously rotated to exchange heat, but the heat storage body 36 and the oxidation catalyst 39 are Alternatively, the partition structure 38 may be configured as a rotatable hood, and heat exchange may be performed by switching and rotating the partition structure 3B.

"Effects of the Invention" As explained above, according to the present invention, the gas containing combustible components is passed through the heat-receiving fluid side flow path of the rotary regenerative heat exchanger to be heated to a temperature higher than the activation temperature of the catalyst in advance, and then the gas is heated to the oxidation catalyst. Since they are brought into contact with each other, combustible components such as carbon oxide and hydrocarbons can be effectively oxidized. Then, the temperature of the gas is further increased by the heat of oxidation of the combustible components, and this gas is brought into contact with the oxidation catalyst again, so that SOx, tar, etc. contained in the gas adhere to the catalyst and become activated. Even if these decrease, they can be desorbed to regenerate the catalyst. Furthermore, since this high-temperature gas is passed through the heat radiation fluid side flow path of the rotary regenerative heat exchanger, it can be used to preheat newly incoming gas containing combustible components. Therefore, combustible component-containing gas can be stably treated for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing an example of a rotary regenerative heat exchanger for carrying out the present invention, and FIG. 2 is a sectional view taken along the line ■--■ in FIG. 31...Casing, 32...Fluid inlet, 33...
・Fluid outlet, 34... Rotating shaft, 36... Heat storage body, 3
8... Partition structure, 38... Oxidation catalyst, 40... Header. Engraving of the drawing (no changes to the content) Rod 1 drawing name z drawing hand HC? City official document (method) q 1, 1986

Claims (1)

[Claims] 1. Gas containing combustible components is passed through the heat-receiving fluid side flow path of the rotary regenerative heat exchanger, heated to a temperature higher than the activation temperature of the oxidation catalyst, and brought into contact with the oxidation catalyst in that state. to oxidize the combustible components, further raise the temperature of the gas by the heat of oxidation, bring this gas into contact with the oxidation catalyst again to regenerate the oxidation catalyst, and further heat dissipation from the rotary regenerative heat exchanger. A method for processing a gas containing combustible components, characterized by passing the gas through a fluid side flow path and taking it out. 2. The treatment method according to claim 1, wherein the oxidation catalyst has one or more selected from Ru, Rh, Pd, and Pt as an active species. 3. Claim 1 or 2, wherein a combustible component is further added to the gas containing the combustible component.
Treatment method described in section.