JPH10249142A - Exhaust gas treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust treatment device provided with a desorption tower enabling to efficiently regenerate an adsorbent at high temp. SOLUTION: Heaters 27 are provided on a desorption part 17 of the desorption tower 13 provided with the exhaust gas treatment device, and adsorbent carbon is dopped on the heaters 27 to directly heat the adsorbent carbon. The adsorbent carbon is heated until a desorption temp. at high temp., and gas originated from organic matters adsorbed on the adsorbent carbon is easily desorbed most of the adsorbed gas at high temp., and the adsorbent carbon is regenerated to one nearly equal to new activated carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exhaust treatment apparatus provided with a desorption tower for regenerating an adsorbent for removing an organic raw gas contained in exhaust gas.

In recent years, semiconductor devices (LS) have been installed in semiconductor factories.
With the mass production of I), an exhaust treatment device for removing an organic raw gas contained in the exhaust gas of the semiconductor device manufacturing device with an adsorbent is installed. Since the adsorbent is regenerated in the desorption tower in the exhaust treatment device and is recycled, it is required to regenerate the adsorbent efficiently.

[0003]

2. Description of the Related Art FIG. 9 (a) is a schematic vertical sectional view of a desorption tower 1 provided in a conventional exhaust treatment device. Activated carbon as an adsorbent obtained by adsorbing an organic raw gas in an adsorption tower (not shown) is supplied to the desorption tower 1 from its upper end. The activated carbon is heated in the desorption section 2. When the activated carbon is heated to the desorption temperature, the organic raw gas adsorbed on the activated carbon separates from the activated carbon to regenerate the activated carbon. The regenerated activated carbon is cooled in the cooling unit 3 and supplied to the adsorption tower again.

[0004] As shown in FIG. 9 (b), a desorption section 2 is provided with a brass electric heater 4 provided along the inner surface of a cylindrical desorption tower 1, and a radial section between the center of the desorption tower 1 and the heater. And fins 5 to which the heat of the heater is conducted. The fins 5 are provided so as to partially overlap each other in the vertical direction (the front and back sides in FIG. 9B) so that the activated carbon does not drop directly. Therefore, the activated carbon is indirectly heated by the heat conducted to the fins 5 hit when falling.

[0005]

Incidentally, in recent years, in the process of manufacturing a semiconductor device, an organic raw gas having a high boiling point (for example, N-methyl-2-pyrrolidone (NMP),
° C) is being used. Therefore, in the desorption tower 1, it is necessary to regenerate the activated carbon by heating the activated carbon to a high desorption temperature of 200 ° C. or higher corresponding to the organic raw gas having a high boiling point.

However, in the conventional desorption tower 1, since the activated carbon is indirectly heated by the fins 5 provided radially from the heater 4, it is difficult to heat the activated carbon to a high temperature of 200 ° C. or more, and the activated carbon is efficiently produced. Can't play. When the activated carbon is regenerated at a low temperature, the adsorption capacity of the activated carbon is reduced and the processing capacity of the exhaust treatment device is reduced. For example, the specific surface area showing the adsorption performance of activated carbon regenerated at low temperature is reduced to about 40% of the specific surface area of new activated carbon. Therefore, in the conventional exhaust treatment device, it is necessary to always replace the activated carbon with new activated carbon in order to maintain the treatment capacity,
Since the replacement requires a lot of cost, there is a problem that the operating cost of the exhaust treatment device increases.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an exhaust treatment apparatus provided with a desorption tower capable of efficiently regenerating an adsorbent at a high temperature. is there.

[0008]

In order to achieve the above-mentioned object, the present invention according to claim 1 is characterized in that an adsorbent which is supplied from a supply port provided at an upper end and adsorbs a raw gas which falls down in a tower is adsorbed by a predetermined amount. In an exhaust treatment apparatus provided with a desorption tower having a desorption section for regenerating the adsorbent by heating to a desorption temperature, a heater for heating an adsorbent falling in the tower is directly mounted in the desorption tower. The gist is that you have done it.

According to a second aspect of the present invention, in the exhaust treatment apparatus according to the first aspect, a recess is formed in a surface of the heater so that a partial surface of the adsorbent is in contact with the heater. The invention according to claim 3 is the exhaust treatment device according to claim 1 or 2, wherein a space between the supply port and the heater is provided.
The gist of the present invention is to provide a dispersing unit for uniformly dispersing the falling adsorbent in the tower.

[0010] The invention described in claim 4 is the invention according to claims 1 to 3.
In the exhaust treatment device according to any one of the above,
The gist of the invention is that at least a part of the detachable side wall of the detachable side wall has a double structure of an inner wall and an outer wall, and an inert gas is supplied between the inner wall and the outer wall.

According to a fifth aspect of the present invention, in the exhaust treatment apparatus of the fourth aspect, a control means for controlling a supply amount of the inert gas supplied to the inner wall and the outer wall is provided.

[0012] The invention according to claim 6 is the invention according to claims 1 to 5.
In the exhaust treatment device according to any one of the above,
The gist is that a supply port of the desorption tower and a discharge port for discharging the regenerated adsorbent are provided with a valve for sealing the inside of the desorption tower.

(Operation) Therefore, according to the first aspect of the present invention, the adsorbent having adsorbed the raw gas is directly heated by the heater directly mounted in the desorption tower, so that the adsorbent is higher than the boiling point of the raw gas. And the raw gas is desorbed.

According to the second aspect of the present invention, a concave portion is formed on the surface of the heater, the concave portion being in contact with a part of the surface of the adsorbent.
The contact area between the adsorbent and the heater increases. According to the third aspect of the present invention, a dispersing section for uniformly dispersing the falling adsorbent in the tower is provided between the supply port and the heater, and the adsorbent is heated uniformly.

According to the fourth aspect of the present invention, at least a portion of the detachable side wall of the detachable side wall has a double structure of an inner wall and an outer wall, and an inert gas is supplied between the inner wall and the outer wall. The detachable part is kept warm.

According to the fifth aspect of the present invention, the control means for controlling the supply amount of the inert gas supplied to the inner wall and the outer wall is provided, and the supply of the inert gas is controlled. According to the invention described in claim 6, a valve is provided between the supply port of the desorption tower and the discharge port for discharging the regenerated adsorbent, and the inside of the desorption tower is sealed by the valve.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the organic exhaust treatment device 11 of the present embodiment includes an adsorption tower 1
2 and a desorption tower 13 are provided. The adsorption tower 12 is provided for purifying an exhaust gas of a semiconductor manufacturing apparatus (not shown) by adsorbing an organic raw gas contained in the exhaust gas on activated carbon as an adsorbent. The desorption tower 13 is provided to desorb the organic raw gas adsorbed on the activated carbon and regenerate the activated carbon.

The adsorption tower 12 has a lower end connected to a semiconductor manufacturing apparatus (not shown) via a transport pipe 14, and the exhaust of the manufacturing apparatus is supplied to a motor fan 15 provided in the transport pipe 14.
Supplied by In the adsorption tower 12, the activated carbon fluidizing section 1 is provided.
6 are provided in a plurality of stages in the vertical direction. Activated carbon (hereinafter, referred to as desorbed carbon) regenerated in the desorption tower 13 is constantly supplied to the activated carbon flowing section 16 at the uppermost stage. Each activated carbon flowing section 16 horizontally moves the supplied activated carbon in a predetermined direction, and gradually transports the activated carbon from the upper stage to the lower stage.

Therefore, the exhaust gas supplied to the adsorption tower 12 passes between the activated carbons transported by the activated carbon flowing sections 16 while rising from the lower end to the upper end of the adsorption tower 12. The exhaust gas is discharged from the lower end of the adsorption tower 12 as a purified gas, in which the organic raw gas contained in the exhaust gas is adsorbed on the activated carbon and purified. The activated carbon that has absorbed the organic raw gas (hereinafter referred to as adsorbed carbon) is conveyed to the upper end of the desorption tower 13.

The desorption tower 13 is formed in a square cylindrical shape. The desorption tower 13 is provided with a desorption section 17. The desorption section 17 is provided for heating the conveyed adsorbed carbon to a predetermined desorption temperature. The desorption temperature is set to a high temperature (for example, 400 to 500 ° C.) corresponding to the boiling point of the organic raw gas. For example, N-methyl-
In the case of 2-pyrrolidone (NMP), since the boiling point is 202 ° C., the adsorbed carbon is heated to a temperature sufficiently higher than the boiling point of the organic raw gas. Then, the organic raw gas adsorbed on the adsorbed carbon is easily desorbed, and the adsorbed carbon is regenerated to become desorbed carbon.

For example, the present applicant regenerates the adsorbed carbon at a high temperature of 500 ° C. using the exhaust treatment device 11 of the present embodiment, and the specific surface area of the desorbed carbon is about 9% of the specific surface area of the new activated carbon.
It has been obtained by experiment that it is 3%. In addition, the present applicant has obtained through experiments that the specific surface area of the desorbed carbon regenerated by the conventional exhaust treatment device (desorption temperature: 200 ° C.) is about 41% of the specific surface area of the new activated carbon. Accordingly, most of the adsorbed organic raw gas is desorbed from the adsorbed carbon, and the organic raw gas is efficiently removed.

The desorbed coal from which the organic gas has been desorbed is circulated to the adsorption tower 12 and reused. The organic raw gas desorbed from the adsorbed carbon is sent to the concentration tower 18. The condenser tower 19 is provided with a condenser 19, and the organic raw gas sent to the condenser tower 18 is cooled and liquefied by cooling water circulated and supplied to the condenser 19, and stored in a storage tank (not shown) as a recovery solvent.

The exhaust treatment device 11 is provided with an upper transfer section 20. The upper transport section 20 is provided with the adsorption tower 12
Activated carbon is circulated between the column and the desorption tower 13, and the supplied activated carbon is supplied from above each column. The upper transport unit 20 includes an adsorbed coal transport unit 21 and a desorbed coal transport unit 22. Atmosphere is supplied to both transport units 21 and 22 by a motor fan 23. The adsorbed carbon transport unit 21 transports the adsorbed carbon discharged from the adsorption tower 12 by the supplied atmosphere to the upper end of the desorption tower 13. The desorbed coal transport unit 22 transports the desorbed coal discharged from the desorption tower 13 to the upper part of the adsorption tower 12 by the supplied atmosphere.

Next, the structure of the desorption tower 13 will be described in detail with reference to FIGS. As shown in FIG. 2, the desorption tower 13 is provided with a supply port 24 at its upper end, and
Is transported into the desorption tower 13 through the supply port 24 and drops to the desorption section 17.

A dispersing plate 26 as a dispersing portion is provided between the supply port 24 and the attaching / detaching portion 17. Dispersion plate 26
Is provided in order to distribute the supplied desorbed carbon evenly in the horizontal direction with respect to the desorption section 17. The dispersion plate 26
It is made of a metal plate (punched metal) having a plurality of through holes formed with a predetermined inner diameter through which desorbed coal can pass, and is formed in a mountain shape having the center of the desorption tower 13 as an apex.

The adsorbed carbon supplied into the desorption tower 13 falls near the top of the dispersion plate 26 in a concentrated manner. Then, the adsorbed carbon is moved toward the inner wall of the desorption tower 13 by the mountain-shaped dispersion plate 26, and falls onto the desorption section 17 through a through hole formed in the dispersion plate 26. As a result, the adsorbed carbon supplied in a concentrated manner is evenly dispersed in the horizontal direction by the dispersion plate 26 and supplied to the desorption unit 17.

As shown in FIG. 3, the detachable portion 17 is provided with a plurality of heaters 2 over opposed side faces formed in a rectangular cylindrical shape.
7 are directly inserted in a predetermined arrangement. The arrangement of the heaters 27 is set so that the adsorbed carbon that is dispersed and falls always hits the heaters 27.

As shown in FIG. 4, each of the heaters 27 is formed of a material having good heat resistance and heat conductivity in a substantially cylindrical cross section, and includes a nichrome wire 28 for heating the adsorbed carbon 25 therein. In addition, a recess 29 having substantially the same outer shape as that of the adsorbed carbon is formed on the surface of each heater 27. Therefore, since a part of the surface of the adsorbed carbon comes into contact with the concave portion 29, each heater 27
The contact area between the carbon and the adsorbed carbon increases, and the heat of the heater 27 is efficiently transmitted to the adsorbed carbon. Further, since the adsorbed carbon is evenly dispersed by the dispersing plate 26 and falls into the desorption section 17, the temperature of each adsorbed carbon is substantially uniform without variation.

Therefore, the adsorbed carbon is directly heated by the heater 27 while falling in the desorption tower 13, and the heat of the heater 27 is easily transmitted to the adsorbed carbon by a large contact area. As a result, the temperature of each adsorbed carbon rises to a high desorption temperature (500 ° C. in the present embodiment).

Then, most of the organic raw gas adsorbed on the adsorbed carbon is adsorbed by the high temperature and easily desorbed. Therefore, the adsorbed carbon is similar to the new activated carbon (the specific surface area of the regenerated adsorbed carbon is lower than that of the new activated carbon. (More than about 93% of surface area)
It becomes desorbed charcoal regenerated up to. In addition, since each adsorbed carbon is heated to a substantially uniform temperature, each adsorbed carbon is uniformly reproduced without any variation.

The regenerated desorbed coal falls into a cooling unit 30 provided below the desorption unit 17. The cooling unit 30 includes a condenser, and is provided to cool the desorbed coal heated and regenerated in the desorption unit 17. That is, the desorbed coal is cooled by the cooling water supplied and circulated to the cooling unit 30. Then, the cooled desorbed coal is discharged from a discharge port 31 provided at the lower end of the desorption tower 13, and is again supplied to the adsorption tower 12 by the upper transport unit 20.

Therefore, in this embodiment, the adsorbed carbon can be efficiently regenerated as compared with the conventional case of regenerating the activated carbon at a low temperature, so that the activated carbon can be used for a long period of time. As a result, the need to replace the activated carbon is reduced, and the replacement period is lengthened, so that the operating cost of the exhaust treatment device 11 can be reduced. In addition, since the activated carbon can be efficiently regenerated, the ability to adsorb the organic raw gas in the adsorption tower 12, that is, the initial performance of the exhaust treatment device 11, can be easily maintained.

The supply port 24 provided at the upper end of the desorption tower 13 is provided with a solenoid valve 32. An electromagnetic valve 33 is provided at a discharge port 31 provided at the lower end of the desorption tower 13. The two solenoid valves 32 and 33 are used to seal the inside of the desorption tower 13. The two solenoid valves 32 and 33 are provided to keep the temperature inside the desorption tower 13 constant.
That is, when the electromagnetic valve 32 at the upper end is opened, the electromagnetic valve 32
The air in the desorption tower 13 heated by the heater 27 is discharged to the outside of the tower. When the lower electromagnetic valve 33 is opened, air having a lower temperature than that in the desorption tower 13 is supplied into the desorption tower 13 through the electromagnetic valve 33, and the desorption tower 13 is opened.
Temperature in the interior. Therefore, the temperature in the desorption tower 13 can be kept constant by opening and closing the solenoid valves 32 and 33 as appropriate.

The side wall 13a of the desorption tower 13 has an inner wall 3
4 and an outer wall 35, and an inert gas such as nitrogen gas is supplied between the outer wall 35 and the inner wall 34.
Pressure is supplied by opening and closing the solenoid valves 36 and 37 provided at the lower end and the upper end. Therefore, the temperature in the desorption tower 13 is not easily transmitted to the outside by the inner wall 34 and the outer wall 35 of the double structure and the supplied inert gas.
That is, the desorption tower 13 is formed by the double side wall and the inert gas.
Is constituted.

The inert gas is used to keep the temperature inside the desorption tower 13 constant. That is, the solenoid valves 36 and 3
7 is kept closed, the desorption tower 1
The temperature inside 3 is hard to propagate outside and rises. On the other hand, when the solenoid valves 36 and 37 are opened to circulate the inert gas, the temperature inside the desorption tower 13 is lowered by the circulating inert gas. Thereby, the inside of the desorption tower 13 can be maintained at a predetermined temperature.

The double-structured side wall has a so-called explosion-proof structure. That is, even if the inner wall 34 of the desorption tower 13 is damaged due to deterioration or the like, it is possible to prevent the heater 27, the adsorbed carbon, and the like, which have become hot due to the double-walled outer wall 35, from escaping from the damaged portion to the outside of the desorption tower 13. Can be prevented.

On the side wall of the desorption section 17 of the desorption tower 13,
A thermometer mounting port 38 is provided, and a thermometer 39 (not shown in FIG. 2) shown in FIG. 5 is inserted into the desorption tower 13 from the thermometer mounting port. The thermometer 39 is provided for detecting the temperature inside the desorption tower 13 in the desorption section 17. The detected temperature is, for example, the electromagnetic valve 3
2, 33, 36, 37 are used for opening and closing control. That is, based on the temperature inside the desorption tower 13 detected by the thermometer 39, the solenoid valves 32 and 33 are controlled to open and close to discharge the high-temperature gas inside the tower to the outside of the tower and supply the low-temperature air to the inside of the tower. This keeps the temperature inside the desorption tower 13 constant. Also, based on the temperature in the tower, the solenoid valves 36, 3
By controlling the supply and stop of the inert gas by opening and closing 7, the temperature in the tower is kept constant.

Further, a thermometer mounting port 40 is provided on a side wall below the cooling section 30, and a thermometer 41 (not shown in FIG. 2) shown in FIG. 5 is inserted into the desorption tower 13 from the thermometer mounting port. Has been inserted. The thermometer 41 is provided to detect the temperature of the desorbed coal. The detected temperature is used to drive and control the pump 42 shown in FIG. That is, when the temperature of the desorbed coal cooled by the cooling unit 30 is higher than a desired temperature, the pump 42 is drive-controlled to increase the supply amount of the cooling water and lower the temperature of the desorbed coal. ing.

FIG. 5 is a block diagram showing an example of an electrical configuration of the organic exhaust treatment device 11. As shown in FIG. Organic exhaust treatment equipment 1
1, a control device 43 is provided. Control device 43
Are connected to the thermometers 39 and 41, the heater 27, the pump 42, and the solenoid valves 32, 33, 36 and 37.

The control device 43 controls the heater 27 to heat the adsorbed carbon supplied into the desorption tower 13 to a predetermined desorption temperature, and to control the temperature in the desorption tower 13 detected by the thermometer 39. Input, and based on the temperature, the solenoid valve 3
The temperature in the desorption tower 13 is kept constant by controlling the opening and closing of 2 to 37. Further, the control device 43 inputs the temperature of the desorbed coal detected by the thermometer 41, and based on the temperature, the pump 4
2 is controlled to control the supply amount of the cooling water to keep the temperature of the desorbed coal at a predetermined temperature.

As described above, the present embodiment has the following advantages. In the present embodiment, the desorption tower 13
The heater 27 is directly mounted on the desorption section 17 of the above, and the adsorbed carbon is dropped on the heater 27 to directly heat the adsorbed carbon. The adsorbed carbon is heated to a high desorption temperature, and most of the organic raw gas adsorbed on the adsorbed carbon is easily adsorbed and desorbed by the high temperature, and the adsorbed carbon is almost regenerated as well as new activated carbon. As a result, it is not necessary to replace the activated carbon for a long period of time, so that the operating cost of the exhaust treatment device 11 can be reduced. In addition, since the adsorbed carbon is almost regenerated to the same extent as new activated carbon, the ability to adsorb the organic raw gas in the adsorption tower 12, that is, the initial performance of the exhaust treatment device 11, can be maintained for a long time.

Further, a dispersion plate 26 is provided between the supply port of the adsorbed carbon and the desorbing section 17, and the adsorbed carbon is dispersed by the dispersing plate 26 and dropped on the desorbing section 17. Therefore,
Each adsorbed carbon can be heated uniformly.

A concave portion 29 having substantially the same outer shape as that of the adsorbed carbon was formed on the surface of the heater 27. The adsorbed charcoal is
, The contact area increases. Therefore, since the heat of the heater 27 is efficiently transmitted to the adsorbed carbon, the adsorbed carbon can be efficiently heated to a high temperature.

The present invention may be carried out in the following modes in addition to the above embodiment. In the above embodiment, the desorption tower 13
The heating efficiency is increased by providing a mountain-shaped dispersion plate 26 above the desorption section 17 so that the adsorbed carbon that falls is evenly distributed in a plane with respect to the desorption section 17 as shown in FIG. Alternatively, a bifurcated separating portion 26a may be provided to disperse the activated carbon.

In the above-described embodiment, the heat retaining portion is formed by pressurizing and supplying an inert gas such as nitrogen gas between the inner wall 34 and the outer wall 35 as a double-sided overall structure of the desorption tower 13. You may implement so that it may be provided only in a part of column 13. For example, as shown in FIG. 7, only the side surface of the detachable portion 17 may be covered with an inert gas. As shown in FIG. 8, only the side surface of the desorption section 17 is covered with the inert gas, and at least one (both in FIG. 8) of the electromagnetic valves of the supply port 24 and the discharge port 31 is omitted. You may.

In the above embodiment, the recess 29 having a diameter corresponding to the size of the activated carbon is formed on the outer periphery of the heater 27. However, the outer periphery may be formed in any shape such as a simple cylindrical shape.

In the above embodiment, the desorption section 17 for regenerating the adsorbed carbon in the desorption tower 13 and the cooling section 30 for cooling the regenerated desorbed coal are integrally provided.
May be implemented as a separate configuration.

In the above embodiment, the organic raw gas was removed by using activated carbon as an adsorbent.
It may be carried out by using an adsorbent such as activated alumina and a special agent added adsorbent.

In the above embodiment, the present invention is embodied in the exhaust treatment apparatus 11 for adsorbing the organic raw gas and purifying the exhaust gas.
The present invention may be embodied in an exhaust treatment device that adsorbs and treats a source gas other than the organic source gas.

[0050]

As described above, according to the first to sixth aspects of the present invention, there is provided an exhaust treatment apparatus provided with a desorption tower capable of efficiently regenerating an adsorbent at a high temperature. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an organic exhaust treatment device according to an embodiment.

FIG. 2 is a schematic configuration diagram of a desorption tower according to one embodiment.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a cross-sectional view of a heater according to one embodiment.

FIG. 5 is a block diagram showing an electrical configuration of the organic exhaust treatment device.

FIG. 6 is a schematic configuration diagram of another desorption tower.

FIG. 7 is a schematic configuration diagram of another desorption tower.

FIG. 8 is a schematic configuration diagram of another desorption tower.

9A is a schematic vertical sectional view of a conventional desorption tower, and FIG. 9B is a schematic plan sectional view.

[Description of Signs] 11 Exhaust treatment device 13 Desorption tower 17 Desorption unit 25 Activated carbon as adsorbent 26 Dispersion plate as dispersion unit 27 Heater

Claims (6)

[Claims] 1. A desorption tower having a desorption section for heating an adsorbent, which is supplied from a supply port provided at an upper end thereof and adsorbing raw gas falling in the tower to a predetermined desorption temperature, to regenerate the adsorbent, is provided. In the exhaust treatment device, the heater for heating the adsorbent falling in the tower is directly installed in the desorption tower in the desorption section. 2. The exhaust processing apparatus according to claim 1, wherein a concave portion is formed on the surface of the heater so that a partial surface of the adsorbent is in contact with the heater. 3. The exhaust gas treatment apparatus according to claim 1, further comprising a dispersion section between the supply port and the heater for uniformly dispersing the falling adsorbent in the tower. 4. The exhaust gas treatment apparatus according to claim 1, wherein at least a portion of the detachable side wall of the detachable side wall has a double structure of an inner wall and an outer wall. An exhaust treatment device that supplies an inert gas between itself and the outer wall. 5. The exhaust processing apparatus according to claim 4, further comprising a control unit that controls a supply amount of the inert gas supplied to the inner wall and the outer wall. 6. The exhaust treatment device according to claim 1, wherein a supply port of the desorption tower and a discharge port for discharging the regenerated adsorbent are provided inside the desorption tower. Exhaust treatment device equipped with a sealing valve.