JP2001058117A - Method for treating exhaust gas and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously remove tacky substances and malodorant components in exhaust gas by pre-forming an adsorbent layer of a desired thickness in the primary side of a filter cloth by feeding to a bag filter an adsorbent of an average particle size of a specific value and clean air and after then feeding exhaust gas to the bag filter. SOLUTION: An adsorbent comprising, for example, active carbon powder of an average particle size of 1-100 micron meter, preferably 1-approximately 30 micron meter is charged into an adsorbent feed hopper 5. The adsorbent is fed to an exhaust gas duct P1 through an adsorbent feed pipe 7 by the suction force of an exhaust fan F and the feed of high-pressure air, and also is fed into a bag filter 1 after being mixed with clean air through an air introducing pipe 4, and is sticked on the primary surface of a filter cloth 2 to form an adsorbent layer of a desired thickness. Then, the exhaust gas containing resin components and malodorant components is fed into the bag filter 1. The exhaust gas is exhausted into the atmosphere through an exhaust gas duct P2 after passing through the filter cloth 2, tacky substances are sticked on the near- surface place of the adsorbent layer, and the malodorant components are adsorbed in the adsorbent to be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating an exhaust gas containing an adhesive substance such as a tar mist or a tar component and a malodorous component such as an organic compound, and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, the exhaust gas from a drying oven provided in a coating facility or a printing facility or the exhaust gas from a metal heat treatment furnace contains high levels of organic solvents, plasticizers or surfactants generated by thermal decomposition. It contains a sticking substance such as a so-called tar mist, oily smoke mist, and a mist component having a boiling point, and a malodorous component composed of an organic compound such as aldehydes and carboxylic acids.

[0003] For this reason, the odorous components contained in the exhaust gas from a drying oven or the like are generally subjected to a direct combustion treatment or a catalytic combustion treatment using a heat storage combustion type deodorizer or a catalytic combustion type deodorizer.

However, when the exhaust gas containing the adhesive substance is directly treated by a thermal storage combustion type deodorizer or a catalytic combustion type deodorizer, the adhesive substance adheres to the surface of the thermal storage material or the catalyst and removes the thermal storage material or the like for a short time. In some cases, clogging occurs or the catalyst surface is coated (so-called poisoning), making deodorizing treatment impossible.

[0005] Therefore, a filtering device such as a cyclone or a bag filter or an electric dust collector is installed upstream of the deodorizing device so that tar mist and tar components in the exhaust gas are removed in advance and then supplied to the deodorizing device. Was.

[0006]

However, in the above-mentioned filtration apparatus, there was a problem that the dust could hardly be collected because the average particle size of the tar mist and the tar component was as small as about 0.3 μm. For example, a bag filter, which is one of the filtration devices, targets particles of 1 micron or more in dust collection.

When the electric dust collector collects dust mist and tar components, the tar mist and the like adhere to the electrode plate of the electric dust collector and the dust collecting effect is weakened. Therefore, the electrode plate is periodically cleaned. There was a problem that had to be.

The inventors of the present invention have made various studies and found that the bag filter has an average particle size of 0.3 as described above.
It is not possible to collect tar mist and tar components of about micron, but if powder of 1 to 100 micron, preferably 30 micron or less is uniformly adhered and laminated to a filter cloth of bag filter to a thickness of 10 mm or more, the Fine particles of about 0.3 micron can be collected with high efficiency.
It has been found that malodorous substances can be removed at the same time by using a porous adsorbent such as zeolite and diatomaceous earth.

Accordingly, the present invention provides an adsorbent layer formed of a porous adsorbent of 1 to 100 microns on the primary side of a filter cloth of a bag filter, and supplying the exhaust gas to the adsorbent layer to thereby form the adhesive substance. It is an object of the present invention to provide an exhaust gas treatment method and an exhaust gas treatment device for removing odor components.

[0010]

In order to achieve the above object, the present invention provides a bag filter having an average particle diameter of 1 to 100 microns when treating an exhaust gas containing an adhesive substance and a malodorous component with a bag filter. An adsorbent and clean air are supplied to adhere the adsorbent to the primary side of the filter cloth to a predetermined thickness to form an adsorbent layer in advance, and then the exhaust gas is supplied to a bag filter to supply the adsorbent. The layer removes adhesive substances and odorous components in the exhaust gas.

Further, an exhaust gas treatment apparatus is provided, wherein a bag filter is provided at a predetermined position of an exhaust gas duct through which exhaust gas containing an adhesive substance and an odor component flows, and an exhaust fan is provided downstream of the bag filter. An adsorbent supply hopper for supplying an adsorbent having an average particle diameter of 1 to 100 microns to a predetermined position of an exhaust gas duct upstream of the bag filter via a supply pipe, and a filter cloth secondary of the bag filter. A high-pressure air supply means for backwashing is provided on the side, and a return pipe is provided for returning an adsorbent that separates and falls from the filter cloth primary side at the time of backwashing to the adsorbent supply hopper,
Further, the present invention is an exhaust gas treating apparatus provided with a damper for controlling the flow of exhaust gas at a predetermined position of an exhaust gas duct upstream of a connection portion between the supply pipe and the exhaust gas duct.

Further, there is provided an exhaust gas treatment apparatus provided with an air supply pipe provided with a valve at a predetermined position upstream of a connection portion between the supply pipe of the adsorbent supply hopper and the exhaust gas duct and downstream of the damper.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings.
It is explained according to. In the figure, reference numeral 1 denotes a conventionally known bus.
The filter cloth 2 is provided inside the filter.
The exhaust gas from the drying oven of the coating equipment is not
Exhaust gas duct P ₁Supply into the bag filter 1 through
After passing through the filter cloth 2,
Adhesive substances and odorous components are removed, and exhaust gas
To P_TwoIt is more likely to be released to the atmosphere. In addition,
F is an exhaust fan.

On the secondary side of the filter cloth 2 in the bag filter 1, a high-pressure air supply pipe 3 for backwashing is provided.

[0015] 4 at the air inlet tube which communicates with the exhaust gas duct P ₁ of the upstream side, an exhaust gas duct P ₁ by opening and closing of the valve V ₁
It supplies clean air to the air. Further, the damper V ₂ in the exhaust gas duct P ₁ on the upstream side of the connecting portion a of the air inlet pipe 4 are installed.

[0016] 5 the adsorbent feed hopper has a dispensing valve V ₃ at the bottom, and the adsorbent supply pipe 7 provided with a three-way valve V ₄ via the mixer 6, the exhaust gas duct P ₁ It communicates downstream from the connection part a with the air introduction pipe 4. Also,
The other end of the mixer 6 is in communication with the high pressure air source (not shown) via a valve V _5.

Further, a discharge valve V ₆ is provided at the lower end of the bag filter 1. One end of the discharge valve V ₆ is connected to the adsorbent supply hopper 5 via a return pipe 9, and the other end is connected to the discharge valve V _6. forming a circulation path of the adsorbent S is connected to a mixer 8 connected via a valve V ₇ to the high pressure air source not the shown.

Next, the operation of the exhaust gas treatment apparatus having the above configuration will be described. First, in the structure, the adsorbent feed hopper 5, the average particle diameter of 1 to 100 microns, preferably 1-30 microns, for example, the adsorbent S consisting of activated carbon powder was charged, the valve V ₁ open the damper V ₂ closed, three-way valve V _4, together with a communication with adsorbent supply pipe 7, drives the metering valve V ₃ while driving the exhaust fan F, to a valve V ₅ opened. It should be noted that the valve V ₇ is closed.

Thus, the adsorbent S is supplied from the adsorbent supply pipe 7 to the exhaust gas duct P ₁ by the suction force of the exhaust fan F and the supply of high-pressure air, and is mixed with clean air from the air introduction pipe 4. Into the bag filter 1 and filter cloth 2
After adhering to the primary surface of the filter cloth 2 for a predetermined time, an adsorbent layer Sa having a predetermined thickness (at least 10 mm) is formed on the primary surface of the filter cloth 2.

[0020] Thus, the predetermined thickness of the adsorbent layer Sa is formed, the driving of the dispensing valve V ₃ is stopped, the valve V _1, V ₅ and damper V ₂ and at the same time closed is opened An exhaust gas containing a tarnish component and a malodorous component is supplied into the bag filter 1.

As described above, the exhaust gas supplied into the bag filter 1 passes through the filter cloth 2 and then passes through the exhaust gas duct P _2.
The exhaust gas is discharged to the atmosphere via the exhaust fan F. During this time, the tarnish component adheres to the vicinity of the surface of the adsorbent layer Sa, and the malodorous component is also adsorbed by the adsorbent S and removed. At this time, the adhesive substances such as tar mist and tar components adhere to the surface portion of the adsorbent layer Sa and do not enter the inside, and thus have no effect on the adsorption and removal of the offensive odor component.

When the adsorption process is performed for a predetermined time, an adhesive substance adheres to the surface of the adsorbent layer Sa around each of the adsorbents S, resulting in a so-called clogged state. Stop F and damper V
₂ is closed, and high-pressure air for backwashing is supplied from the high-pressure air supply pipe 3 to the secondary side of the filter cloth 2. In this case, since the adhesive substance hardly exists at the contact portion of the adsorbent layer Sa with the filter cloth 2 as shown in FIG. 2A, high-pressure air for back washing is supplied to the secondary side of the filter cloth 2. Then, as shown in FIG. 2B, the adsorbent layer S
a separates from the surface of the filter cloth 2 and falls to the lower part of the bag filter 1.

[0023] Thereafter, filtration driving the discharge valve V _6, the valve V ₇ is opened, the adsorbent S 'peeled falling back into the adsorbent feed hopper 5, and mixed with fresh adsorbent, again by the process described above An adsorbent layer Sa is formed on the surface of the cloth 2 to remove the sticky substances and odorous components in the exhaust gas.

In returning the separated adsorbent S ',
As shown in FIG. 3, the lower part of the bag filter 1 and the discharge valve V ₆
A storage tank 10 provided with a stirring and transporting unit 11 such as a screw conveyor is provided between the tanks, and the separated adsorbent S 'is stirred and then returned to the adsorbent supply hopper 5 so that the adsorbent is made uniform. You may.

The backwashing of the filter cloth 2 may be performed at predetermined time intervals as described above. However, as the adhesive substance adheres to the surface of the adsorbent layer Sa, the resistance that passes through the filter cloth 2 is reduced. Since the pressure difference increases and the pressure difference between the primary side and the secondary side of the filter cloth 2 increases, the pressure difference may be measured, and the backwash may be performed when the measured value exceeds a predetermined set value.

[0026] While repeating the backwash operation described above, since most of the surface of the adsorbent S is adsorption performance is coated with an adhesive substance falls below a predetermined value, the damper V ₂ closed, exhaust fan F
The stop adsorbent S in the bag filter 1 communicates with a three-way valve V ₄ After returning all the adsorbent feed hopper 5 to the outside of the system, drives the metering valve V ₃ the valve V ₅ is opened, suction The adsorbent S in the material supply hopper 5 is discharged out of the system. Thereafter, a new adsorbent S is replenished into the adsorbent supply hopper 5, an adsorbent layer Sa is formed on the primary surface of the above-mentioned filter cloth 2, and the exhaust gas is treated.

In the above-described embodiment, the adsorbent S is supplied to the bag filter 1 by using high-pressure air. However, as shown in FIG. 4, a three-way valve V ₃ is provided above the exhaust gas duct P _1. an adsorbent supply hopper 5 through the adsorbent supply pipe 7 having provided, by gravity the adsorbent S to exhaust gas duct P ₁ by driving the metering valve V _3, exhaust fan F
May be driven to mix the clean air supplied from the air supply pipe 4 with the adsorbent S by the suction force of the exhaust fan F and supply the mixed air to the bag filter 1.

Further, in the above-described embodiment, when the adsorbent S is supplied to the bag filter 1, clean air is supplied from the air introducing pipe 4. May be omitted so that the air introduction pipe 4 is not provided.

In the above description, the particle size of the adsorbent S is 1 to
The reason why the thickness of the adsorbent layer Sa is set to 100 mm or more and the thickness of the adsorbent layer Sa is set to 10 mm or more is that if the diameter is smaller than 1 micron, the particles pass through the filter cloth 2 and the adsorbent layer Sa is not formed.
This is because, when the diameter exceeds micron, the filter cloth 2 is separated from the filter cloth 2 by its own weight, and a layer of 10 mm or more cannot be formed on the surface of the filter cloth 2. Also, the thickness of the adsorbent layer Sa is 10
If the thickness is smaller than 0 mm, the malodorous component composed of ultrafine particles cannot be completely captured.

[0030]

As is apparent from the above description, claim 1
In the invention according to the present invention, the exhaust gas is passed through the porous adsorbent layer having a predetermined thickness formed on the primary surface of the filter cloth of the bag filter, thereby simultaneously removing the sticky substances such as tar mist and tar components and the bad odor component in the exhaust gas. Therefore, it is not necessary to separately treat the adhesive substance and the malodorous component as in the related art.

Further, in the invention according to claim 2,
Even if the adsorption capacity of the porous adsorbent is reduced, the adsorbent layer can be easily separated from the filter cloth 2 by back washing of the bag filter and can be reused, which is economical. However, in the invention according to the second aspect, since the removal of the adhesive substance and the deodorization of the malodorous component can be simultaneously processed by one bag filter, the device can be simplified. In addition, the device itself is inexpensive.

Further, in the invention according to the third aspect, since the air supply pipe is provided at a predetermined position of the exhaust gas duct upstream of the bag filter, it is possible to suppress the amount of high-pressure air used.

Further, in the present invention, since the adhesive substance adheres to the porous adsorbent layer and adheres little to the inner wall of the apparatus, there is an effect that almost no cleaning work of the apparatus is required.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an exhaust gas treatment apparatus according to the present invention.

FIG. 2 (A) is an enlarged view of an adsorbent layer and a filter cloth surface,
(B) is a diagram showing peeling of the adsorbent layer.

FIG. 3 is a diagram showing another embodiment below a bag filter.

FIG. 4 is a partial view showing another means for supplying the adsorbent to the bag filter.

[Explanation of symbols]

1 bag filter, 2 filter cloth, 3 high-pressure air supply pipe for backwash, 4 air introduction pipe, 5 adsorbent supply hopper, 6, 8
~ Mixer 7 adsorbent supply pipe 9 to return pipe, F. to the exhaust fan, P _1, P ₂ - exhaust gas _{duct, V 1, V 5, V} 7 ~ valve,
V ₂ ~ damper, V ₃ ~ metering valve, V ₄ ~ three-way valve, V ₆ ~ discharge valve.

Continued on the front page F term (reference) 4D002 AA40 AB02 AB03 BA04 BA14 BA16 CA20 DA41 DA45 DA47 EA07 GA01 GA02 GB02 GB04 GB12 HA06 4D058 JA04 JB34 MA15 NA04 PA04 PA09 SA08 TA03 TA07

Claims (3)

[Claims] When an exhaust gas containing an adhesive substance and a malodorous component is treated with a bag filter, an adsorbent having an average particle size of 1 to 100 microns and clean air are supplied to the bag filter to thereby form a primary side of a filter cloth. Adsorbing the adsorbent to a predetermined thickness to form an adsorbent layer in advance, and then supplying the exhaust gas to a bag filter to remove the sticky substance and the malodorous component in the exhaust gas by the adsorbent layer. A method for treating exhaust gas, comprising the steps of: 2. An exhaust gas treatment apparatus comprising: a bag filter disposed at a predetermined position of an exhaust gas duct through which exhaust gas containing an adhesive substance and a malodorous component flows; and an exhaust fan disposed downstream of the bag filter. An adsorbent supply hopper for supplying an adsorbent having an average particle diameter of 1 to 100 microns to a predetermined position of an exhaust gas duct upstream of the bag filter via a supply pipe, and a filter cloth secondary of the bag filter. A high pressure air supply means for backwashing is provided on the side, and a return pipe is provided for returning an adsorbent that separates and falls from the filter cloth primary side at the time of backwashing to the adsorbent supply hopper,
An exhaust gas treatment device, wherein a damper for controlling the flow of exhaust gas is disposed at a predetermined position of the exhaust gas duct upstream of a connection portion between the supply pipe and the exhaust gas duct. 3. An air supply pipe having a valve at a predetermined position upstream of a connection between a supply pipe of the adsorbent supply hopper and an exhaust gas duct and downstream of the damper. The exhaust gas treatment device according to claim 2.