JP3498523B2 - Exhaust gas treatment equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for purifying an exhaust gas in which dust, water, harmful volatile organic compounds, malodorous components, etc. are mixed in a gas, and a granular catalyst fixed bed type combustion oxidation is used. The present invention relates to an exhaust gas treatment device capable of easily performing a regeneration treatment of a granular catalyst fixed bed of the device.

[0002]

2. Description of the Related Art For example, exhaust gas generated in various manufacturing processes such as a casting process often contains various kinds of dust, water, harmful volatile organic compounds, malodorous components, etc. It is common to use a granular catalyst fixed bed type combustion oxidizer for purification treatment of volatile organic compounds and malodorous components in combination with a dust collector for purification treatment of the above dust.

However, if the particulate catalyst fixed bed type combustion oxidizer is continuously operated for a long time, catalyst poisons such as silica compounds in the gas are deposited on the surface of the particulate catalyst to deteriorate the catalytic performance. Therefore, there is a problem that it is necessary to perform the catalyst replacement work regularly, and continuous operation for a long time cannot be performed and the processing efficiency is lowered. On the other hand, as a method of preventing the accumulation of the catalyst poison as described above, it is considered that the deterioration of the catalyst performance is delayed by raising the combustion temperature of the combustion oxidation device from the normal temperature of about 300 ° C to about 500 ° C.
In this case, the equipment cost and running cost are high, which is not practical.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems and efficiently discharges exhaust gas containing dust, water, harmful volatile organic compounds, malodorous components, etc. for a long time. The present invention has been completed with the object of providing an exhaust gas treatment apparatus that can be purified and can easily perform a regeneration treatment of a granular catalyst fixed bed of a granular catalyst fixed bed type combustion oxidation device.

[0005]

The exhaust gas treating apparatus of the present invention made to solve the above-mentioned problems includes a dust collector for collecting and removing dust in the exhaust gas, and a harmful volatile component and an offensive odor component in the exhaust gas. In the exhaust gas treatment system that is connected to a granular catalyst fixed bed combustion oxidation system that removes by combustion,
It consists of a blower and an air volume adjustment damper between the device and the dust collector.
A closed loop structure is provided in which an air flow rate adjusting means is provided, and a feedback gas circulation path connecting the outlet of the combustion oxidizer and the dust collector is provided, and the particulate catalyst fixed bed is fluidized and regenerated in the gas circulation path. It is characterized in that a switching damper means for use is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. The drawing shows the case of purifying the moist exhaust gas generated at the time of separating the casting and the raw sand after the casting in the foundry, and 1 in the figure shows dust, water, harmful volatile organic compounds and malodorous components. A suction hood covering the mixed exhaust gas generation source 10, 2 is a bag filter type dust collector for collecting and removing dust in the exhaust gas, 3 is a blower, and 4 is a burner for harmful volatile components and malodorous components in the exhaust gas. This is a granular catalyst fixed bed combustion oxidizer for removal, and the above configuration is basically the same as a conventional exhaust gas treating apparatus of this type.

In the present invention, a gas circulation path 5 for feedback connecting the outlet of the combustion oxidizer 4 and the inlet of the dust collector 2 is provided, and the particulate catalyst fixed layer 4a flows through the gas circulation path 5. It has a characteristic configuration in that a switching damper means for a closed loop configuration for converting into a reproduction process is provided. That is, normally, the exhaust gas is purified by the dust collector 2 and the granular catalyst fixed bed type combustion oxidizer 4 to remove dust, harmful volatile organic compounds, malodorous components, etc. When the catalyst deterioration of the granular catalyst fixed layer 4a occurs, a feedback gas circulation path 5 connecting the outlet of the combustion oxidizer 4 and the inlet of the dust collector 2 is formed by operating the switching damper means, and this closed loop state is formed. By circulating the gas in the gas circulation path 5, the granular catalyst fixed layer 4a is fluidized, and the catalyst poison accumulated on the catalyst surface is removed and regenerated.

The switching damper means for the closed loop construction is a switching damper 7 for opening and closing the suction of the exhaust gas to the dust collector 2.
a, a switching damper 7b that opens and closes the communication of the gas circulation path 5 to the dust collector 2, and a switching damper 7c that opens and closes the discharge of the processing gas of the combustion oxidizer 4 and are used during normal purification processing. When the switching dampers 7a and 7c are opened and the switching damper 7b is closed, on the other hand, when the granular catalyst fixed layer 4a is fluidized and regenerated, the switching damper 7b is opened and the switching dampers 7a and 7c are closed. Good.

Further, the blower 3 provided between the dust collector 2 and the combustion oxidizer 4 is provided with an air volume adjusting means consisting of an air volume adjusting damper 8 for the normal operation and the granular catalyst fixed bed. It is configured so that the gas flow rate during the regeneration treatment of 4a can be adjusted to an optimum value. By the way, in the illustrated apparatus, the gas flow rate during the regeneration process was set to be about 1.2 to 1.5 times the gas flow rate during normal operation and operated. The air volume adjusting means may be, for example, a mechanism for adjusting the rotation speed of the blower 3 under inverter control. A heat exchanger 6 is built in the granular catalyst fixed bed type combustion oxidizer 4 so that the combustion oxidizer 4 can be operated efficiently.

With such a structure, the rare gas generated in the generation source 10 is collected by the suction hood 1 and introduced into the dust collector 2 to remove dust in the exhaust gas, and then the combustion oxidizer 4 is used.
It is basically the same as the conventional exhaust gas treating apparatus of this type in that the volatile component and the odorous component are burned and removed to perform the purification treatment after the temperature is introduced into the heat exchanger 6 and the temperature is raised by the heat exchanger 6. is there. If the catalyst performance deteriorates due to inactive catalyst poisons such as silica compounds in the gas accumulated on the surface of the granular catalyst after continuous operation for a long time, the switching damper 7b
And a switching damper 7a, 7c is closed to form a closed loop using the gas circulation path 5, and further the gas flow rate is increased by about 1.2 to 1.5 times to operate the granular catalyst fixed bed. 4a is fluidized and the catalyst is regenerated. That is, the inactive layer covering the surface of the granular catalyst by this regeneration treatment is, as shown in FIG.
Due to the collision and abrasion of the granular catalysts, they are separated and the surface is activated again. Further, at this time, the separated inactive layer is introduced into the dust collector 2 through the gas circulation path 5 and is removed, so that it is not released into the atmosphere.
There is no concern about air pollution. After the regeneration process of the granular catalyst is completed in this way, the switching damper 7 is again activated.
When a and 7c are opened and the switching damper 7b is closed and normal operation is resumed, the dust collection removal processing of dust in the exhaust gas and the combustion removal processing of harmful volatile components and malodorous components are restarted again. By repeating the above, the exhaust gas purification process can be continuously operated for a long time.

[0011]

As is apparent from the above description, the present invention can efficiently purify exhaust gas containing dust, water, harmful volatile organic compounds, malodorous components, etc. for a long time, In addition, it is possible to easily regenerate the granular catalyst fixed bed of the granular catalyst fixed bed type combustion oxidizer, and as a result, it is not necessary to perform regular catalyst replacement work as in the past, and it is a large work. In addition to being able to improve efficiency, it is possible to significantly reduce equipment costs and running costs. Further, it has an advantage that it can be improved by only adding a gas circulation path for feedback and a switching damper for a closed loop configuration to the conventional apparatus, and a low cost system with low equipment cost can be provided. Therefore, the present invention, as an exhaust gas treatment apparatus that eliminates the conventional problems, is extremely important in contributing to industrial development.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing a case where a granular catalyst fixed bed is subjected to a fluidization treatment.

[Explanation of symbols]

2 dust collector 4 Combustion oxidizer 4a Granular catalyst fixed bed 5 gas circulation 6 heat exchanger 7a switch damper 7b switching damper 7c switching damper 8 Air volume adjustment damper

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-112515 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01D 53/86

Claims (3)

(57) [Claims] 1. Exhaust gas in which a dust collector (2) for collecting and removing dust in exhaust gas and a granular catalyst fixed bed type combustion oxidizer (4) for burning and removing harmful volatile components and malodorous components in exhaust gas are connected. in the processing apparatus, the combustion oxidizer (4)
A blower (3) and an air volume adjustment damper between the dust collector (2)
(8) An air volume adjusting means is provided, and a feedback gas circulation path (5) connecting the outlet of the combustion oxidizer (4) and the inlet of the dust collector (2) is provided, and the gas circulation path (5) is also provided. The exhaust gas treating apparatus is characterized in that it is provided with a switching damper means of a closed loop configuration for fluidizing and regenerating the granular catalyst fixed layer (4a). 2. The switching damper means includes a switching damper (7a) that opens and closes suction of exhaust gas to the dust collector (2) and a switching damper (7b) that opens and closes communication of the gas circulation path (5) to the dust collector (2). And a switching damper (7c) for opening and closing the discharge of the processing gas from the combustion oxidizer (4).
The exhaust gas treatment device according to item 1. 3. A granular bed fixed bed combustion oxidizer (4).
A heat exchanger (6) is built in the said 1 or 2.
The exhaust gas treatment device according to item 1.