JPH04126520A - Waste gas treating device - Google Patents

Abstract

PURPOSE:To reduce the cost and to improve reliability in treatment by roughly removing an org. solvent in the fluidized bed of an adsorption tower, removing the low-concn. solvent in the fixed bed provided in the fluidized bed and making the height of the fluidized bed different from that of a regeneration tower. CONSTITUTION:A fluidized bed 4 in which a first adsorbent 9 is circulated through the flow holes 7 of plural beds 8 and a fixed bed 5 are provided in an adsorption tower 2. The org. solvent is roughly removed by the first adsorbent 9 of the fluidized bed 4, and the low-concn. solvent is removed by a second adsorbent 10 of the fixed bed 5. Consequently, the second adsorbent 10 can be used for a long period, and the running cost is reduced. Furthermore, many kinds of components can be removed, and reliability in treatment is improved. The exhausted first adsorbent 9 is sent by a conveyor line 14a and regenerated. The height of the regeneration tower 3 is made different from that of the fluidized bed 4. Namely, highly reliable treatment is performed in the case when priority is given to the fluidized bed or to the regenerating means.

Description

[Detailed Description of the Invention] [Summary] Regarding an exhaust gas treatment device that treats exhaust gas containing various types of organic solvents at low concentrations, the present invention aims to reduce costs and improve processing reliability. In the exhaust gas treatment device, the exhaust gas treatment device includes an adsorption means for adsorbing and removing an organic solvent contained in an adsorption member, and a regeneration means for regenerating the adsorption member, wherein the adsorption means is provided with a plurality of layers of a floor portion having a flow hole formed therein. a fluidized bed in which a predetermined amount of a first adsorption member is fluidized;
a fixed bed filled with an adsorption member, and the exhaust gas is configured to pass from the fluidized bed to the fixed bed, and the first adsorption member in the fluidized bed mainly performs rough removal. The second adsorption member in the fixed bed removes the low-concentration organic solvent, and the regeneration means has a plurality of bed sections each having a plurality of flow holes formed therein. Regeneration is performed by fluidizing one adsorption member, and the height of the bed of the regeneration means is made different depending on the number of layers of the bed of the fluidized bed.

[Industrial application field]

The present invention relates to an exhaust gas treatment device for treating exhaust gas containing various types of organic solvents at low concentrations.

In recent years, for example, a wide variety of organic solvents such as alcohol and petroleum are used in semiconductor manufacturing processes.
A large amount of air is exhausted to maintain process stability and the working environment, resulting in a low exhaust concentration. Therefore,
It is necessary to treat even this low-concentration exhaust gas effectively and at low cost.

[Conventional technology]

Traditionally, there are two methods of exhaust gas treatment: an adsorption method and a combustion method (including catalytic oxidation). When the concentration of exhaust gas to be treated is low, the adsorption method is generally used due to running costs and stability. It is.

Adsorption methods include a fluidized bed method and a fixed bed method (activated carbon particles, activated carbon fibers), and FIG. 3 shows a conventional exhaust gas treatment device. Figure 3 (A) is a conceptual diagram of the fluidized bed type;
B) is a conceptual diagram of a fixed bed type.

In FIG. 3(A), the interior of the adsorption tower 20 is formed in multiple stages, and activated carbon 21 in the form of spherical particles flows through a large number of alternately formed flow holes. Exhaust gas with a lower concentration flows in through the inflow hole 22 formed at the bottom stage, and gas from which organic components have been removed is discharged from the top stage.

Furthermore, the inside of the regeneration tower 23 is also formed in multiple stages, and the activated carbon 21a to be regenerated flows through the flow holes. A heater 24 is provided on the side of this regeneration tower 23.

Then, the contaminated activated carbon 21 is sent along with air from the bottom of the adsorption tower 20 to the top of the regeneration tower 23 via a transport line 25a, and the contaminated activated carbon 21 is sent from the bottom of the regeneration tower 23 to the top of the adsorption tower 20 via a transport line 25b. The activated carbon 21a is sent together with air.

Such a fluidized bed type exhaust gas treatment device uses activated carbon 21
The regeneration of a is heated (approximately 200"C) with a heater 24, and nitrogen (N2) is added to improve the regeneration efficiency. In other words, since no steam is used during regeneration, there is an advantage that no waste water is generated. The activated carbon can be continuously transferred outside the system and sufficiently heated in the regeneration tower 23.The organic solvent regenerated from the activated carbon 21a in the regeneration tower 23 is cooled in a condenser and recovered.

Next, in FIG. 3(B), two towers 30a.

30b is alternately adsorbed and regenerated. tower 30a
, 30b are filled with activated carbon particles 31a, 31b (or activated carbon fibers). For example, if the tower 30a is an adsorption tower, the tower 30b is a regeneration tower. In this case, the tower (adsorption) 30
Exhaust gas 32 is supplied from below a through a valve 33a and discharged from above through a valve 33b, while steam is supplied from above a column (regeneration) 30b through a valve 34c, and the regenerated organic The solvent is cooled and recovered using a condenser. After the adsorption in the column 30a has been carried out for a predetermined period of time, the column 30b is used as an adsorption column, and the column 30a is used as an adsorption column.
A is a regeneration tower. In this case, supply and discharge are carried out through the respective valves 33a to 33c and 34a to 3.
Controlled by 4c.

Such a fixed bed type exhaust gas treatment device has the advantage of low running costs and no influence even if the concentration or amount of exhaust gas fluctuates.

[Invention or problem to be solved]

However, in the fluidized bed type, the adsorption reaction rate is generally 0.
．． 8 m/see ~1.1 m/sec (maximum 1.0
m/5ec), and since the activated carbon 21 flows, it is difficult to perform more uniform and reliable adsorption against fluctuations in exhaust gas concentration and amount. Furthermore, if reliable removal (adsorption) is to be performed using a fluidized bed method, only an adsorption tower with a height of 10 m or more will be sufficient to remove low concentration levels.
Furthermore, in the case of a low adsorption tower, the amount of N2 used for regeneration must be increased, which increases running costs. On the other hand, in a fixed bed type, if the activated carbon is in the form of particles, the device will be large and the set area will be large. Furthermore, in the case of activated carbon or fibrous material, the amount of steam used during regeneration increases, the amount of exhaust gas increases, or a separate device for removing water is required, increasing running costs.

As described above, there is a problem in that the adsorption method cannot achieve reasonable initial costs, running costs, and maintenance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an exhaust gas treatment device that reduces costs and improves processing reliability.

[Means to solve the problem]

The above problem is solved by an exhaust gas treatment device having an adsorption means for adsorbing and removing an organic solvent contained in exhaust gas on an adsorption member, and a regeneration means for regenerating the adsorption member, in which the adsorption means has a communication hole or the like. a fluidized bed in which a predetermined amount of the first adsorption member is fluidized by providing a plurality of bed sections;
a fixed bed filled with a predetermined amount of the second adsorption member;
The solution is to pass the exhaust gas from the fluidized bed to a fixed bed. Further, the first adsorption member in the fluidized bed mainly performs rough removal, the second adsorption member in the fixed bed removes the organic solvent at a low concentration, and the regeneration means , regeneration is performed by fluidizing the first adsorption member provided in a plurality of layers in a bed portion having communication holes, and the height according to the number of layers of the bed portion of the regeneration means and the bed portion of the fluidized bed. Formed with different heights depending on the number of layers.

[Effect]

As mentioned above, in the adsorption means, a fluidized bed and a fixed bed are provided in the fluidized bed. That is, the first adsorption member flows through the flow holes in the bed section of the plurality of layers in the fluidized bed. Therefore,
The exhaust gas is processed by flowing into a fluidized bed, passing through the fluidized bed, and then passing through a fixed bed. For example, a first adsorption member in a fluidized bed mainly performs coarse removal, and a second adsorption member in a fixed bed removes low-concentration organic solvents. That is, by performing rough removal with the first adsorption member and precise removal with the second adsorption member, the second adsorption member (fixed bed) can be operated for a long period of time, and running costs can be reduced. Furthermore, it becomes possible to remove various components, thereby improving the reliability of the process.

Further, the first adsorbent is regenerated by a regeneration means, and the height of the regeneration means and the height of the fluidized bed of the adsorption means are formed to be different. That is, it is possible to perform more reliable processing when placing emphasis on the fluidized bed (the fluidized bed is high) or when placing emphasis on the regeneration means (the regeneration means is high).

〔Example〕

FIG. 1 shows a configuration diagram of an embodiment of the present invention. In FIG. 1, an exhaust gas treatment device 1 includes an adsorption tower 2 which is an adsorption means.
and a regeneration tower 3 which is a regeneration means.

The adsorption tower 2 consists of a fluidized bed 4 and a fixed bed 5.
Exhaust gas flows into the fluidized bed 4 through the duct 6 at the bottom of the fluidized bed 4. The exhaust gas is passed through a fixed bed 5, and the treated exhaust gas is discharged from above the fixed bed 5. The fluidized bed 4 is provided in multiple layers in a bed portion 8 having a predetermined number of flow holes 7 formed therein, and the first adsorption member 9 flows therein. In addition, a second
The adsorption member 10 is filled.

Here, the first adsorption member 9 is made of activated carbon for polymers, which is suitable for moisture removal and durable, and the second adsorption member l
O is used in activated carbon or selected amounts for long-life small molecules. For polymers, those with large diameter adsorption grooves on the activated carbon surface are mainly selected, and for low molecules, those with small diameters are selected.

On the other hand, similar to the fluidized bed 4 of the adsorption tower 2, the regeneration tower 3 is provided with a plurality of layers in the bed section 12 in which the flow holes 11 are formed, in which the first adsorption member 9 that has already been adsorbed is fluidized. is played.

Further, this regeneration tower 3 is provided with a heater 13.

Further, a conveyance line 14a is provided between the bottom of the fluidized bed 4 of the adsorption tower 2 and the top of the regeneration tower 3, and the adsorbed first adsorption member 9 is sent to the regeneration tower 3 by air. On the other hand, the first adsorption member 9 regenerated by the regeneration tower 3
is sent from the bottom to the top of the fluidized bed 4 via a conveyance line 14b.

In such an exhaust gas treatment apparatus 1, exhaust gas containing an organic solvent flows into the fluidized bed 4 from the duct 6 of the adsorption tower 2. In the fluidized bed 4, moisture, high concentration organic matter, etc. are removed by the activated carbon for polymers of the first adsorption member 9, and then in the fixed bed 5, low concentration organic matter is removed. When the first adsorption member 9 in the fluidized bed 4 becomes contaminated due to repetition of such processing, it is sent to the regeneration tower 3 via the conveyance line 14a.

In the regeneration tower 3, by heating with a heater 13 while supplying nitrogen (N2), water and high concentration organic matter separated from the first adsorption member 9 are discharged with nitrogen, and are liquefied and recovered by a condenser. Then, the regenerated first adsorption member 9
is again sent to the fluidized bed 4 of the adsorption tower 2 via the conveyance line 14b, and these steps are repeated.

In this way, since the fluidized bed 4 of the adsorption tower 2 performs rough removal and the fixed bed 5 performs precise removal, it is possible to remove various components, and the second adsorption member 10 of the fixed bed 5 can be removed. It is possible to extend the service life, thereby reducing running costs.

Note that the exhaust gas treatment apparatus 1 in FIG. 1 shows a case where the adsorption tower 2 is formed higher than the regeneration tower 3.

This is because, as mentioned above, the absolute amount adsorbed by the activated carbon of the first adsorption member 9 is constant, so the fluidized bed 4
This is because when a high amount of activated carbon is formed and the amount of activated carbon is large, it is not necessary to perform regeneration treatment of a large amount of activated carbon in the regeneration tower 3. That is, the removal efficiency in the fluidized bed 4 is increased and the reliability of the treatment is improved.

Here, FIG. 2 shows a configuration diagram of another embodiment of the present invention.

The exhaust gas treatment apparatus 1A shown in FIG. 2 has a regeneration tower 3A higher than the fluidized bed 4A of the adsorption tower 2A, and the other configurations are the same as in FIG. 1.

That is, since the first adsorption member 9 of the fluidized bed 4A is small in quantity and has a high adsorption concentration, it takes a sufficient amount of time to perform regeneration in the regeneration tower 3A.

With this, as well as in FIG. 1, it is possible to remove various components, reduce running costs, and improve processing reliability.

〔Effect of the invention〕

As described above, according to the present invention, a fixed bed is provided in a fluidized bed,
In addition, by performing rough removal in a fluidized bed and removing low-concentration organic solvents in a fixed bed, and by making the heights of the fluidized bed and regeneration tower different, it is possible to remove various components and reduce running costs. The reliability of processing can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram of another embodiment of the present invention, and FIG. 3 is a conceptual diagram of a conventional exhaust gas treatment device. In the figure, 1. IA is an exhaust gas treatment device, 2.2A is an adsorption tower, 3.3A is a regeneration tower, 4.4A is a fluidized bed, 5 is a fixed bed, 6 is a duct, 7; 11 is a flow hole, 8 .12 is a floor, 9 is a first suction member, IO is a second suction member, 13 is a heater, and 14a and 14b are conveyance lines. Fig. 1 is a block diagram of an embodiment of the present invention; Fig. 1 is a block diagram of another embodiment of the present invention (A); Fig. 3 is a conceptual diagram of a conventional exhaust gas treatment device.

Claims (1)

[Scope of Claims] (1) Exhaust gas treatment device comprising adsorption means (2) for removing organic solvents contained in exhaust gas by adsorption to an adsorption member, and regeneration means (3) for regenerating the adsorption member. In this case, the adsorption means (2) is a fluidized bed (4) that includes a plurality of bed sections (8) in which flow holes (7) are formed and in which a predetermined amount of the first adsorption member (9) is fluidized.
and a fixed bed (5) filled with a predetermined amount of the second adsorption member (10) in the fluidized bed (4), and the exhaust gas is transferred from the fluidized bed (4) to the fixed bed (5). ). (2) The first adsorption member (9) in the fluidized bed (4) is
The exhaust gas treatment apparatus according to claim 1, wherein the exhaust gas treatment apparatus mainly performs rough removal, and the second adsorption member (10) in the fixed bed (5) removes the organic solvent at a low concentration. . (3) The regeneration means (3, 3_A) has a communication hole (7, 1
1) is provided in multiple layers, and the first adsorption member (9) is fluidized and regenerated;
The height depending on the number of layers of the bed section (12) of the regeneration means (3, 3_A) and the height depending on the number of layers of the bed section (8) of the fluidized bed (4, 4_A) are formed to be different. The exhaust gas treatment device according to claim (1) or (2).