JP2001074205A - Catalytic combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid an abnormal rise in temperature of a raw gas and maintain excellent combustion by exchanging heat between the raw gas which has passed through a heat exchanger and the raw gas which has passed through a bypass portion. SOLUTION: A catalytic combustion device 10 is provided for combusting a used organic solvent for decomposition into hydrocarbon and water, for instance. The device comprises a catalytic portion 12 for combusting an organic solvent 11 (hereinafter referred to as a raw gas including, for instance, xylene, benzen, toluen, methane or the like) under a given catalyst, and comprises a heater 13 for heating the raw gas 11 up to a given combustion temperature. The device further comprises a first heat exchanger 15 for exchanging heat between the combusted raw gas, i.e., an exhaust gas 14 whose temperature has been raised high and the raw gas 11, and comprises a raw gas bypass portion 16 for permitting a portion or entire raw gas 11 to bypass the first heat exchanger 15. Still further, the device comprises a second heat exchanger 18 for exchanging heat between a raw gas 17 which has been thus bypassed and the raw gas 11 which has passed through the heat exchanger 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic combustion device for burning an organic solvent, decomposing it into carbon dioxide and water, and discharging the gas.

[0002]

2. Description of the Related Art Conventionally, organic solvents have been used in various technical fields (for example, in the cleaning and coating industries). Such an organic solvent cannot be directly discarded as industrial waste, but is generally burned using a catalytic combustion device, decomposed into carbon dioxide and water, and discharged. FIG. 2 is a schematic view of a conventional general catalytic combustion device.

Referring to FIG. 1, a catalytic combustion device 1 includes a heating unit 2 for heating air containing an organic solvent or the like (hereinafter, referred to as “raw gas”) to a predetermined combustion temperature, and a heating unit 2. A catalyst unit 3 for burning the raw gas, a heat exchanger 4, and a raw gas bypass unit 5 are provided. The heat exchanger 4 is configured to mix the raw gas (normally at normal temperature) introduced into the catalytic combustion device 1 with the catalytic unit 3.
The heat is exchanged with the gas (hereinafter, referred to as “combustion gas”) burned in the above, and the energy required for heating the raw gas is reduced. A part or the whole is directly supplied to the heating unit 2 without passing through the heat exchanger 4, and can be generally adjusted by an automatic flow control valve 6.

The reason for providing such a raw gas bypass section 5 is as follows. That is, the concentration of the raw gas varies depending on the environment in which the catalytic combustion device 1 is used. Then, depending on the concentration of the raw gas, when the total heat exchange is performed by the heat exchanger, the combustion temperature becomes too high, and there is a possibility that the catalyst unit 3 may be damaged by heat. For this reason, in order to suppress a rise in combustion temperature, part or all of the raw gas is directly supplied to the heating unit without passing through the heat exchanger 4.

[0005]

By the way, in such a catalytic combustion device 1, by bypassing a part of the raw gas, the raw gas that has been heat-exchanged and the raw gas that has not been heat-exchanged are located before the heating section. At this time, the two gases do not mix uniformly. For this reason, temperature unevenness occurs in the raw gas, and it becomes difficult to realize good combustion of the raw gas in the catalyst unit 3 as it is. Conventionally, in order to solve such a problem, a gas stirrer or the like is provided between the bypass merging section 7 and the heating section 2 to mitigate the temperature unevenness of the raw gas.

However, by providing such a gas stirrer or the like, the catalytic combustion device 1 becomes large and its structure becomes complicated. Further, the cost of the entire apparatus also increases.

Therefore, the present invention can realize good combustion by suppressing an abnormal rise in the combustion temperature of the raw gas.
It is an object of the present invention to provide an inexpensive and compact catalytic combustion device.

[0008]

In order to achieve the above object, a catalytic combustion apparatus according to the present invention comprises a heating section for heating a raw gas to a combustion temperature, and a combustion section for burning the heated raw gas to produce a combustion gas. A catalyst section for discharging, a heat exchanger having a raw gas insertion section through which the raw gas is inserted and a combustion gas insertion section through which the combustion gas is inserted, and performing heat exchange between the two gases; and a part or all of the raw gas In a catalytic combustion device having a raw gas bypass unit that supplies gas to a heating unit directly without passing through a heat exchanger without passing through a heat exchanger, the raw gas that has passed through the heat exchanger and the raw gas that has passed through the raw gas bypass unit A heat exchanger for exchanging heat between them is provided.

According to this configuration, it is possible to eliminate the temperature unevenness generated between the raw gas passing through the heat exchanger and the raw gas passing through the raw gas bypass.

[0010]

Embodiments of the present invention will be described below.

FIG. 1 is a diagram showing a configuration of a catalytic combustion device (hereinafter simply referred to as “device”) 10 according to an embodiment of the present invention.

Referring to FIG. 1, an apparatus 10 is used for, for example, burning a used organic solvent to decompose it into hydrocarbons and water. The apparatus 10 includes a catalyst section 12 for burning an organic solvent (hereinafter, simply referred to as “raw gas”) 11 as a raw gas under a predetermined catalyst, and a heating section for heating the raw gas 11 to a predetermined combustion temperature. A heating unit 13, a first heat exchanger 15 for exchanging heat between the burned raw gas, that is, the high-temperature exhaust gas 14 and the raw gas 11, and a first heat exchanger 15 for part or all of the raw gas 11 Heat exchanger 15
Raw gas bypass section 16 for bypassing the raw gas 1 and the raw gas 1 that has passed the first heat exchanger 15
And a second heat exchanger 18 for exchanging heat with the first heat exchanger 18.

The raw gas 11 varies depending on the environment in which the apparatus 10 is used. For example, xylene, benzene,
Toluene, methane, ethane and the like.

The catalyst section 12 burns the raw gas 11 (17) under a predetermined catalyst at a predetermined atmospheric temperature. Although various catalysts can be employed, in the present embodiment, a platinum catalyst is employed.

The heating section 13 is provided with a predetermined heating means. In this embodiment, an electric heater or the like is employed.

The first heat exchanger 15 may be, for example, a cross flow type, but is not limited thereto, and may be a counter flow type or a shell tube type.

The second heat exchanger 18 is a source gas 1 which has been heat-exchanged between the source gas 17 bypassed by the source gas bypass unit 16 and the exhaust gas 14 by the first heat exchanger 15.
The first heat exchanger 15 has the same configuration as that of the first heat exchanger 15. However, the second heat exchanger 18 may have a structure different from that of the first heat exchanger 15.

The raw gas bypass section 16 bypasses the raw gas 11 as described above, and is provided with an automatic flow control valve 19 for adjusting the bypass amount. Providing the bypass path in this way has a large relationship with the heat resistant temperature of the catalyst unit 12. That is, the catalyst unit 12
The raw gas 11 (17) is burned at a predetermined temperature. However, since the heat-resistant limit temperature of the catalyst is approximately 500 ° C., the temperature in the catalyst section 12 is usually controlled within the range of 250 ° C. to 450 ° C. There is a need.

On the other hand, the combustion temperature of the raw gas 11 (17) is
It depends greatly on the type of gas and its concentration,
The concentration varies greatly depending on the environment in which the device 10 is used. Then, the raw gas 11 (17) having a high combustion temperature and a high concentration
In the environment where is supplied, the first gas
When the heat exchange is performed by the heat exchanger 15, the combustion temperature becomes extremely high, and the catalyst unit 12 is damaged. In order to prevent this, the automatic flow control valve 19 is adjusted to control the bypass amount of the raw gas 11 so that the heat exchange efficiency of the first heat exchanger 15 is reduced.

According to the device 10 having such a configuration, in an environment where a predetermined amount of bypass is required for the raw gas 11,
The raw gas 11 and the raw gas 17 merge at a junction 20. For this reason, the raw gas 11 (17) passing through the junction 20
Temperature unevenness occurs, and as it is, even if heated by the heating unit 13, the temperature unevenness cannot be eliminated,
Good combustion in the catalyst unit 13 cannot be realized.

However, in the present apparatus 10, the raw gas 11 (17) passing through the junction 20 is heat-exchanged with the exhaust gas 14 by passing through the second heat exchanger 18, thereby eliminating temperature unevenness. can do. Thereby, the catalyst unit 1
The combustion of the raw gas 11 (17) in 2 can be improved. Moreover, the raw gas 11 (1
There is no need to provide a device for stirring 7), and the entire device 10 can be reduced in size and manufactured at low cost.

Particularly, in the apparatus 10 according to the present embodiment, the first
The same heat exchanger 15 and the second heat exchanger 18 are adopted, and they are arranged in series. Therefore, it is not necessary to manufacture the second heat exchanger 18 in particular. Further cost reduction can be realized.

[0023]

As described above, according to the invention of the present application, it is possible to eliminate uneven temperature occurring between the raw gas passing through the heat exchanger and the raw gas passing through the raw gas bypass section. In addition, the combustion of the raw gas in the catalyst section can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a structure of a catalytic combustion device according to an embodiment of the present invention.

FIG. 2 is a schematic view showing the structure of a conventional catalytic combustion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Catalytic combustion apparatus 11 Raw gas 12 Catalytic unit 13 Heating unit 14 Exhaust gas 15 First heat exchanger 16 Raw gas bypass unit 17 Raw gas 18 Second heat exchanger

Claims (1)

[Claims] 1. A heating section for heating a raw gas to a combustion temperature, a catalyst section for burning the heated raw gas and discharging a combustion gas, a raw gas insertion section through which the raw gas is inserted, and a combustion gas A heat exchanger having a combustion gas insertion portion through which heat is exchanged between the two gases, and a raw gas supplied to the heating portion directly without passing through the heat exchanger, bypassing part or all of the raw gas In a catalytic combustion device having a bypass portion, a heat exchanger for exchanging heat between the raw gas passing through the heat exchanger and the raw gas passing through the raw gas bypass portion is provided. Catalytic combustion device.