JP4673780B2 - Hazardous gas removal equipment - Google Patents

Description

The present invention relates to a detoxification apparatus that removes harmful gas components contained in a processing gas by adsorbing them to a detoxifying agent. It relates to harmful equipment.

  In semiconductor manufacturing plants, etc., volatile inorganic hydrides that are hydrogen compounds such as arsenic and phosphorus, halogen compounds and organic compounds in which these hydrogen atoms are substituted with halogen atoms or alkyl groups, acidic gases such as fluorine and chlorine, or Various harmful gases represented by basic gases such as ammonia and hydrazine are used. Before exhaust gases containing these harmful gases are discharged into the atmosphere, it is necessary to detoxify the harmful gas components.

  As such detoxification treatment, there is a dry detoxification method in which exhaust gas is circulated through a detoxification tower filled with a solid detoxifying agent, and harmful gas components are adsorbed to the detoxifying agent or decomposed by the action of the detoxifying agent. Many have been adopted. However, in the case of such a method, there is an inherent limit in the amount of harmful gas that can be detoxified by the detoxifying agent per unit amount, and it is not possible to adsorb or decompose more than a predetermined amount of harmful gas. In other words, there is a limit to the amount of harmful gas that can be removed by a detoxification tower filled with a certain amount of a detoxifying agent. A so-called breakthrough phenomenon occurs in which the harmful gas passes through the detoxification tower without being detoxified.

Therefore, in order to prevent the leakage of undetoxified harmful gases, the presence or absence of breakthrough of the detoxifying agent is constantly monitored, the operation is stopped before the detoxifying tower loses its detoxifying capacity, and the detoxifying agent is replaced or It is necessary to update by refreshing. Therefore, conventionally, the presence or absence of breakthrough of the detoxifying agent has been detected mainly by one of the following two methods.
1) The detection agent that changes color by contact with harmful gas is packed in layers between the main removal agent layer and the preliminary removal agent layer, and the color change is observed visually or with a color mark sensor or the like through a viewing window. This is a method for detecting breakthrough of the main scavenger layer (see Patent Document 1 below).
2) Is it possible to detect that an abatement tower filled with an abatement agent is arranged in series in the front and rear stages and the weight of the rear abatement tower starts to increase (see Patent Document 2 below) or the abatement tower? A method of detecting breakthrough of the abatement tower in the previous stage by installing a gas detector between them (see, for example, Patent Document 3 below).

Japanese Patent Laid-Open No. 10-2894 JP-A-7-185256 JP 2002-267606 A

However, with regard to the detection method described in Patent Document 1, if the removal device is stopped immediately after the breakthrough of the main removal agent layer is quickly detected by the detection agent, the preliminary removal agent layer is used at all. Since this is renewed without being carried out, the use of the detoxifying agent occurs. On the other hand, if the preliminary detoxifying agent layer is not provided or the amount is reduced and packed, the detection agent discoloration detection delay occurs when drift occurs in the flow of harmful gas in the detoxifying tower. There arises a problem that the harmful agent layer may already break through and the harmful gas may leak out.
Even when such a detoxification tower filled with the main detoxifying agent layer and the pre-determination agent layer is provided in multiple stages in series, the main detoxification is caused by the detection agent filled between the two. This is a problem that can occur in the same manner as long as breakthrough of the agent layer is detected.

Moreover, about the detection method of the said patent document 2, by knowing whether or not the detoxifying agent started to adsorb harmful gas by measuring the weight of the detoxifying tower in the subsequent stage, Since it is based on the principle of detecting breakthrough, the detection accuracy is not high in the first place. This is because the downstream abatement tower is always loaded with a load corresponding to the pressure loss generated when passing through it, and the processing gas is removed from the downstream without using a special pressure regulator. In the case of the present invention introduced into the harmful tower, the measurement result of the weight of the latter-stage harmful tower using a load cell or the like always involves considerable fluctuation. Therefore, when detecting the increase in the weight of harmful gas flowing into the latter stage due to the breakthrough of the first stage detoxifying agent, the slight change in the weight of the detoxification tower is buried in the above fluctuation, so When a clear increase in the weight of the tower is detected, the previous detoxifying agent has broken through long before. That is, the time lag from the occurrence of breakthrough of the first stage detoxification tower to the detection by the second stage is considerable.
On the other hand, in order to continuously operate an in-series abatement apparatus such as the treatment apparatus described in Patent Document 2, before the rear-stage detoxifying agent breaks through after the previous stage, the previous stage that has already broken through Since the detoxifying agent must be updated and installed downstream of the rear-stage detoxification tower, the above-mentioned detection delay of the breakthrough in the front stage is extended to the post-stage detoxification tower. There is an essential problem that it is necessary to compensate for the increase in the amount of the detoxifying agent to be filled, resulting in an increase in the size of the apparatus.

  In addition, the detection method described in Patent Document 3 detects breakthrough of the abatement device by a breakthrough detector that combines a special gas concentration measuring device and an alarm device. Cause up. In addition, when a general gas detector is used as a breakthrough detector, the sensor of the detector is significantly deteriorated, and it is necessary to replace the detector every time the breakthrough pesticide is updated. There is also a problem that it interferes with continuous operation. This is because the gas detector is a device for confirming the absence of the gas and is not made on the assumption that the gas detector is continuously exposed to high-concentration gas. This is because when a general gas detector detects high-concentration harmful gas that flows in due to excessive flow, the sensitivity of the sensor is unavoidable, and without replacement, the hazardous gas may soon be undetectable. . In addition, using a special sensor that can withstand continuous exposure to a high concentration of harmful gas naturally has a problem of increasing costs.

The present invention has been made in order to solve the above-mentioned problems, the detoxifying agent filled in the detoxifying tower can be used without waste, breakthrough of the detoxifying agent can be detected quickly, and as well as a possible continuous implementation of the abatement process can be miniaturized inexpensive apparatus, and to provide a removal device for implementing the abatement of hazardous gases.

The harmful gas removal apparatus according to the present invention, in the removal apparatus in which the removal tower is arranged in series in the front stage and the rear stage, occurrence of breakthrough of the removal agent filled in the previous stage removal tower, This is based on the technical idea of detecting the presence or absence of discoloration of the detection agent provided in the abatement tower.

The harmful gas removal apparatus according to the present invention is:
(1) A detection window including a detection agent container loaded with a detection agent that changes color by contact with harmful gas and a viewing window for observing the color change of the detection agent is provided, and adsorbs the harmful gas. A detoxification device in which at least two or more types of detoxification towers filled with a detoxifying agent to be detoxified are arranged in series, and the introduced harmful gas is detoxified by passing through the two or more types of detoxification towers. The detection agent is a compound different from the detoxifying agent, and a processing gas is stored in the detoxifying tower upstream of the packed detoxifying agent in the flow direction of the passing harmful gas. A space is formed,
A detoxifying device, wherein at least part of the detection agent container is directly exposed to the processing gas storage space;
(2) At least a part of the detection agent positioned on the outermost surface visible from the viewing window is directly exposed to the processing gas storage space through the breathable detection agent container (1) Abatement device as described in);
(3) A gas inlet for introducing the harmful gas flowing through the detoxification tower into the detection agent container while providing the processing gas contact surface (gas contact surface ) of the viewing window to coincide with the inner wall surface position of the detoxification tower The abatement device according to (1) or (2) above, wherein at least the gas contact surface of the viewing window is formed;
(4) The abatement apparatus according to any one of (1) to (3), wherein the abatement apparatus includes at least first and second abatement towers arranged in series, and a treatment gas containing a harmful gas is introduced. The treatment gas is introduced into the first removal tower, the treatment gas discharged from the first removal tower is guided to the second removal tower, and the treatment discharged from the second removal tower A first gas line for deriving the gas out of the system, and a treatment gas is introduced into the second detoxification tower, and the treatment gas discharged from the second detoxification tower is led to the first detoxification tower, A detoxification device comprising a second gas line for deriving the processing gas discharged from the first detoxification tower outside the system, and a switching means for switching the flow path of the processing gas to the first gas line or the second gas line ;
Is the gist.

Furthermore, in the present invention,
( 5 ) The first gas line introduces the processing gas into the first detoxification tower, the pipe communicating the first and second detoxification towers, and the treatment discharged from the second detoxification tower It consists of piping that leads gas out of the system,
The second gas line includes a pipe for introducing the processing gas to the second detoxification tower, a pipe for communicating the second and first detoxification towers, and the processing gas discharged from the first detoxification tower. Consisting of piping leading out,
The switching means has a function of switching the flow path into which the processing gas containing harmful gas is introduced to the first or second detoxification tower, and the flow path of the processing gas discharged from the first detoxification tower to the second. One or more switching valves having at least a function of switching to a detoxification tower or outside of the system and a function of switching the flow path of the processing gas discharged from the second detoxification tower to outside of the first detoxification tower or system The abatement apparatus according to ( 4 ) above,
( 6 ) The abatement apparatus according to any one of ( 1 ) to ( 5 ), wherein the detection window is detachably attached to the abatement tower;
( 7 ) Any of the above ( 1 ) to ( 6 ), wherein the processing gas contact surface of the viewing window coincides with the inner wall surface position of the detoxification tower or is provided closer to the center of the detoxification tower than the position An abatement device according to crab;
The above-mentioned problems can be solved and the object of the present invention can be achieved.

The harmful gas removal apparatus according to the present invention detects the breakthrough of the removal agent filled in the removal tower, not in the removal tower, but in the downstream removal tower arranged in series. It is observed and detected by a window or the like. As a result, it is not necessary to fill the detoxifying tower with the preliminary detoxifying agent layer in both the first and second stages, and this can be detected after the detoxifying agent filled in the first detoxifying tower has completely passed through. Therefore, waste of the pesticide that remains unused is eliminated.
In addition, when detecting the breakthrough of the packed pesticide on the downstream side of the pesticide in the pesticide tower, when a drift occurs in the harmful gas flowing through the pesticide. Where there is a risk that detection delay may occur due to a reaction delay of the detection agent, by providing the detection agent in the vicinity of the inlet to which harmful gas is introduced as in the abatement apparatus according to the present invention, It is expected that no harmful gas drift occurs in the surroundings, and that the detection agent exhibits a color change reaction quickly and reliably.
In addition, according to the present invention, it is possible to immediately detect the breakthrough of the removal agent in the previous stage by visually observing the discoloration of the detection agent filled in the detection window. For example, the weight of the removal column is measured. Compared with the conventional detection method performed in this way, the occurrence of a breakthrough phenomenon can be detected quickly and reliably without being caused by fluctuations in gas flow velocity or pressure. For this reason, the amount of the detoxifying agent to be charged in the detoxifying towers in each stage can be suppressed, and the entire detoxifying tower and the detoxifying apparatus can be scaled down, and the handleability is improved.
Furthermore, according to the present invention for detecting the breakthrough of the upstream detoxifying agent by the discoloration of the detecting agent provided in the subsequent stage, the expensive gas detector is not contaminated by exposure to a high concentration of harmful gas. The detection agent in the latter stage used for the detection of breakthrough of the water can be renewed along with the subsequent removal agent, so there is no need to interrupt the removal process. Continuous implementation is possible, and workability and cost are excellent.

  Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings. However, in the present invention, as long as the above-described means are implemented and the above-described effects are obtained, the specific configuration of the piping that communicates between the abatement towers arranged in series and the gas flow path are switched. The specific combinations or arrangement positions of the switching valves are not limited to the following embodiments.

<About the system diagram of the abatement system and the abatement method>
FIG. 1 is a system diagram of a harmful gas removal apparatus according to an embodiment of the present invention. However, the vertical direction in the figure does not mean any vertical or horizontal direction in the installation space of the abatement device, and the flow direction of the harmful gas passing through the abatement tower is a downward flow from the top to the bottom. There is also no limitation on whether the flow is upflow from the vertically downward direction to the upward direction. In addition, a gas inlet and outlet may be formed on one end side of the detoxification tower, and a harmful gas flow path may be formed in a U-shape in the detoxification tower. It is arbitrary whether it is set as a horizontal type or a horizontal type. Regardless of which of these is selected, those skilled in the art can implement the harmful gas removal apparatus according to the present invention by appropriately setting the flow direction of the harmful gas and the primary / secondary interface of the switching valve. can do.

The detoxification apparatus according to the present invention includes at least two or more detoxification towers arranged in series, piping that communicates these, and switching means for switching the gas flow path. In the present embodiment, the abatement apparatus 10 includes a first abatement tower (hereinafter referred to as a first abatement tower) 40a and a second abatement tower (hereinafter referred to as a second abatement tower) 40b. Even if a third or fourth abatement tower is arranged in series, or a plurality of abatement towers arranged in series, a plurality of abatement towers connected in parallel to each other. You may comprise by a tower.
The first and second detoxification towers 40a and 40b have a breathable detection agent container loaded with detection agents 30a and 30b that change color by contact with harmful gas, and a view for observing the color change of the detection agent. Detection windows 20a and 20b each having a window are provided, and the first and second detoxification towers 40a and 40b are respectively filled with detoxifying agents 41a and 41b that adsorb and detoxify harmful gases. ing.
That is, the abatement apparatus 10 is a series multi-column abatement apparatus that adsorbs and removes the introduced harmful gas through two or more series of abatement towers arranged in series.

  The abatement apparatus 10 includes an on-off valve 50a for introducing harmful gas discharged from a semiconductor manufacturing apparatus and the like, and a flow rate adjusting valve for generating a processing gas having a predetermined flow rate by mixing a diluent gas such as nitrogen with the harmful gas. 50b. The pressure of the processing gas may be monitored by the pressure gauge 51, and the opening / closing of the flow rate adjustment valve 50b may be controlled so that a predetermined total pressure is maintained. Nitrogen, hydrogen, argon, helium, etc. are common as a dilution gas. In the present invention, the supply of the dilution gas is optional, and the “processing gas containing a harmful gas” refers to a case where one or two or more kinds of harmful gas and a harmless gas are mixed, and one or two or more kinds. The case of consisting only of harmful gases.

  When harmful gas removal treatment is performed continuously, the removal agent filled in the removal tower gradually loses its removal ability from the inlet side of the harmful gas, and eventually it breaks through to the entire removal tower. A phenomenon occurs. In the abatement apparatus 10 according to the present embodiment, the harmful passing through the detection windows 20a and 20b for detecting the occurrence of breakthrough of the detoxifying agent with respect to the first and second abatement towers 40a and 40b. It is provided respectively on the upstream side in the gas flow direction.

  The abatement apparatus 10 according to the present embodiment includes two gas lines as flow paths for the introduced processing gas. Specifically, the processing gas is introduced into the first abatement tower 40a, the processing gas discharged from the first abatement tower 40a is guided to the second abatement tower 40b, and is discharged from the second abatement tower 40b. The processing gas is introduced into the first gas line 11 (see FIG. 1) for deriving the processed gas out of the system and the second abatement tower 40b, and the processing gas discharged from the second abatement tower 40b It is the 2nd gas line 12 (refer FIG. 3) which guide | induces to the 1 detoxification tower 40a, and guides the process gas discharged | emitted from this 1st detoxification tower 40a out of the system.

As a switching means for switching the flow path of the processing gas, the abatement apparatus 10 according to the present embodiment combines this with two sets of four-way valves 15 and 16 each having two primary sides and two secondary sides. Realized.
Moreover, the 1st gas line 11 connects the piping which introduce | transduces process gas into the 1st removal tower 40a which is a front | former stage, the discharge port of the 1st removal tower 40a, and the introduction port of the 2nd removal tower 40b which is a back | latter stage. It consists of piping and piping which guide | induces the process gas discharged | emitted from the 2nd removal tower 40b out of the system.
On the other hand, the second gas line 12 communicates the piping for introducing the processing gas to the second detoxification tower 40b, which is the front stage, and the discharge port of the second detoxification tower 40b and the introduction port of the first detoxification tower 40a, which is the latter stage. And a pipe for leading the processing gas discharged from the first detoxification tower 40a out of the system. Since the first and second gas lines are selectively used by being switched by the switching means, a part or all of the piping is used in common for both gas lines as in this embodiment. Of course, an individual pipe may be provided for each gas line.

The arrows in FIG. 1 indicate how the processing gas flows through the abatement apparatus 10 according to the first gas line 11 and is led out of the system after being subjected to the abatement process.
The first gas line 11 is used to treat the processing gas introduced into the abatement apparatus 10.
(1) Lead to the inlet 46a of the first detoxification tower 40a through the four-way valve 15,
(2) The detoxification treatment is performed by passing the detoxifying agent 41a packed in the first detoxification tower 40a,
(3) The processing gas discharged from the discharge port 47a of the first removal tower 40a is guided to the introduction port 46b of the second removal tower 40b through the four-way valve 16, the check valve 17 and the four-way valve 15.
(4) A flow path for leading the processing gas discharged from the discharge port 47b of the second detoxification tower 40b out of the system via the four-way valve 16.

  When the processing gas containing harmful gas is introduced into the first detoxification tower 40a, the harmful gas is adsorbed and removed in order from the most upstream side (surface side) of the packed detoxifying agent 41a. Detoxify gas. At this time, in the first abatement tower 40a, a gap is defined as a processing gas storage space 42a on the upstream side in the flow direction of the processing gas, and the detection agent container of the detection window 20a is exposed in the space. When the processing gas containing the harmful gas is introduced into the abatement apparatus 10, the detection agent 30a loaded in the detection agent container quickly contacts the harmful gas and exhibits a discoloration reaction. Visible from the outside through 22a.

  When the harmful gas adsorption / detoxification reaction is performed, the detoxifying agent 41a gradually loses its detoxifying ability from the upstream side, and is not yet in contact with the harmful gas and has not been subjected to the detoxification treatment. The boundary (hereinafter referred to as “breakthrough line”) 45 proceeds downstream of the first abatement tower 40a. In general, the breakthrough line 45 has a substantially flat curved surface as a whole while the center of the abatement tower protrudes slightly downstream in a three-dimensional manner. As shown schematically in Fig. 4, the curve is slightly convex on the downstream side. However, the shape of the breakthrough line 45 varies depending on the local packing density of the detoxifying agent and the affinity between the harmful gas and the inner wall surface of the detoxifying tower.

  On the other hand, a partition member such as a stainless steel mesh 43a (43b) through which the processing gas can pass is stretched under the interior of the detoxification tower, and the bottom of the detoxification tower 41a (41b) is prevented while falling. A detoxifying gas storage section 44a (44b) is defined. The treatment gas that has passed through the detoxifying agent is temporarily stored in the detoxification gas storage unit 44a (44b), and is sent from the discharge port 47a (47b) to the four-way valve 16 through the piping while the pressure is stabilized. It is done.

  When the breakthrough line 45 reaches the stainless steel mesh 43a, the detoxifying agent 41a is broken, and thereafter, the harmful gas component in the processing gas is not sufficiently removed by the first removal tower 40a, and the four-way valve 16, It flows into the second detoxification tower 40 b through the check valve 17 and the four-way valve 15. However, since the second detoxifying tower 40b is filled with a fresh detoxifying agent 41b, the harmful gas is detoxified in the second detoxifying tower 40b, the processing gas is rendered harmless, and the four-way valve 16 and the open / close are opened and closed. It is led out of the system of the abatement apparatus 10 through the valve 50d. In addition, when there is a possibility that both the detoxifying agents filled in the first and second stage detoxification towers may break through, the detoxification apparatus 10 can be safely stopped by closing the on-off valve 50d.

Since the detection window 20b loaded with the detection agent 30b is provided on the upstream side of the second abatement tower 40b, it immediately contacts the detection agent 30b when harmful gas flows into the second abatement tower 40b. A discoloration reaction is caused and breakthrough of the first detoxification tower 40a is detected.
Thus, the detoxification method of detecting the breakthrough of the first detoxification tower 40a by the discoloration of the detection agent 30b provided upstream of the second detoxification tower 40b is actually a breakthrough in the previous detoxification tower. Since this is a method of detecting the occurrence later, there is no waste of renewing a part of the filled pesticides unused. Further, according to this method, the detection agent and the harmful gas come into contact with each other at a position upstream of the removal agent of the second removal tower 40b, and occurrence of discoloration of the detection agent is observed visually or with a color mark sensor or the like. Therefore, it is not affected by the drift of the processing gas containing harmful gas, and the breakthrough of the first stage can be carried out quickly and reliably compared to the conventional removal method that monitors the occurrence of weight increase of the latter removal tower. Can be detected.

  If breakthrough of the first detoxification tower 40a is detected by the detection window 20b, then the second detoxification tower 40b is the previous stage, and the processing gas is first introduced into the inlet 46b of the second detoxification tower 40b. The gas line is switched so that Thereby, while the harmful gas is being removed by the second removal tower 40b, the removal agent 41a of the first removal tower 40a is replaced or refreshed without stopping the removal apparatus 10. Can be updated.

The system diagram shown in FIG. 2 shows a state in which the first abatement tower 40a is removed from the abatement apparatus 10, and the abatement agent 41a filled in the inside and the detection agent 30a loaded in the detection window 20a are exchanged together. Show.
Specifically, the flow path of the four-way valve 15 is switched to guide the harmful gas introduced into the abatement apparatus 10 to the inlet 46b of the second abatement tower 40b. On the other hand, as in FIG. 1, the four-way valve 16 has a flow path for leading the processing gas discharged from the discharge port 47b of the second abatement tower 40b to the outside through the on-off valve 50d. The second abatement tower 40b is filled with a predetermined amount of the detoxifying agent 41b, and the predetermined time until the breakthrough line 45 reaches the stainless mesh 43b provided at the downstream end of the detoxifying agent 41b is as follows. Since the harmful gas can be sufficiently removed only by the second removal tower 40b, the removal process of the harmful gas is performed by updating the removal agent 41a and the detection agent 30a of the first removal tower 40a during this period. It can be carried out continuously without interruption.

  The system diagram shown in FIG. 3 shows a state in which the first abatement tower 40a in which the abatement agent and the detection agent are updated is attached to the abatement apparatus 10 again, and is installed as a subsequent stage of the second abatement tower 40b. Yes. Compared with the state of FIG. 2, although the detoxification process was continuously performed during the replacement operation of the first detoxification tower 40a, the breakthrough line 45 is proceeding to the downstream side of the second detoxification tower 40b. The detoxifying agent 41b is not yet broken through.

The second gas line 12 is selected for the processing gas flow path. That is, the four-way valve 16 is switched so that the processing gas discharged from the discharge port 47b of the second removal tower 40b is led to the four-way valve 15, and the treatment including the harmful gas introduced into the removal apparatus 10 is performed. Gas,
(1) It leads to the inlet 46a of the second abatement tower 40b through the four-way valve 15,
(2) Detoxifying treatment by passing the detoxifying agent 41b packed in the second detoxifying tower 40b,
(3) The processing gas discharged from the discharge port 47b of the second removal tower 40b is guided to the introduction port 46a of the first removal tower 40a through the four-way valve 16, the check valve 17 and the four-way valve 15.
(4) After passing between the refreshed detoxifying agents 41a, the processing gas discharged from the discharge port 47a of the first detoxifying tower 40a is led out of the system through the four-way valve 16 and the on-off valve 50d. A flow path is taken.

Further, when the detoxification process proceeds from this state and the detoxifying agent 41b filled in the second detoxification tower 40b breaks through, a part of the harmful gas passes through the second detoxification tower 40b without being detoxified. , Flows into the first detoxification tower 40a. In this case, the occurrence of breakthrough of the second abatement tower 40b corresponding to the former stage can be quickly detected by the detection window 20a of the first abatement tower 40a corresponding to the latter stage. While the treatment is performed only in the first detoxification tower 40a, the second detoxification tower 40b can be removed and the detoxification agent 41b and the detection agent 30b can be updated as shown in FIG. In this case, the processing gas containing the harmful gas introduced into the first detoxification tower 40a through the four-way valve 15 is detoxified by the detoxifying agent 41a, and the detoxification apparatus 10 through the four-way valve 16 and the on-off valve 50d. Derived outside the system.
When the second abatement tower 40b updated with the abatement agent 41b and the detection agent 30b is attached to the abatement apparatus 10 again, the processing gas is circulated according to the first gas line 11 shown in FIG. The breakthrough of one abatement tower 40a can be detected by the detection window 20b of the second abatement tower 40b at the subsequent stage.
As described above, the abatement apparatus 10 according to the present invention eliminates harmful gas continuously without the need to interrupt the operation when renewing the detoxifying agent or detecting agent of the detoxifying tower that has passed through. Can do.

The switching means for switching the flow path of the processing gas has a function of switching the flow path of the introduced processing gas to the first or second detoxification tower and the flow path of the processing gas discharged from the first detoxification tower. It is particularly limited as long as it has at least a function of switching to the second detoxification tower or outside the system and a function of switching the flow path of the processing gas discharged from the second detoxification tower to the first detoxification tower or outside the system. In addition to an embodiment using two types of four-way valves 15 and 16 as exemplified in the above embodiment, for example, a combination of first to third three-way valves may be used.
In particular,
The primary side of the first three-way valve is used as an inlet for processing gas containing harmful gas discharged from a semiconductor manufacturing apparatus or the like, one of the secondary sides is the inlet 46a of the first abatement tower 40a, and the other is the second. Communicating with the inlet 46b of the detoxification tower 40b;
The primary side of the second three-way valve is connected to the outlet 47a of the first abatement tower 40a, one of the secondary sides is connected to the inlet 46b of the second abatement tower 40b, and the other is connected to the on-off valve 50d;
The primary side of the third three-way valve is connected to the outlet 47b of the second abatement tower 40b, one of the secondary sides is connected to the on-off valve 50d, and the other is connected to the inlet 46a of the first abatement tower 40a. .
In the abatement apparatus 10 having such a configuration, the first gas line 11 is selected as a processing gas flow path by setting the secondary side of each three-way valve to the one side. Moreover, the 2nd gas line 12 is selected as a flow path of process gas by making all the secondary sides of each three-way valve into the said other side.

  The abatement device 10 has an on-off valve as a bypass line when no harmful gas component is mixed with the processing gas or as a bypass line when the first gas line 11 or the second gas line 12 is disconnected. You may provide the exhaust line 13 opened and closed by 50c (refer FIG. 1).

<About the detection window>
5A and 5B are schematic views of the detection window according to the present embodiment, in which FIG. 5A is a front view, and FIG. 5B is a bb cross-sectional view thereof. The abatement apparatus according to the present invention is characterized in that each of the two or more types of abatement towers arranged in series includes a detection window. The detection window 20 is a combination of a gas-permeable detection agent container 23 that transmits a processing gas and a transparent observation window 22. In addition, a flange 25 is provided for fixing to the detoxification tower 40 or for handling at the time of attachment / detachment.
When the detection agent 30 is loaded in the detection agent container 23 and a color change reaction occurs due to contact with harmful gas, the color change can be observed from the outside of the detoxification tower 40 through the observation window 22. Further, the detection window 20 according to the present embodiment has a processing gas reservoir in which the detection agent container 23 is formed on the upstream side of the processing gas flow direction (indicated by a white arrow in the figure) inside the detoxification tower. It is exposed to the space 42.

  Note that the detection windows provided in the multi-stage abatement towers in series may have the same structure or may be different from each other. The abatement apparatus 10 according to this embodiment is provided with a detection window 20 having the same structure. That is, the abatement tower 40 is the same as the first abatement tower 40a and the second abatement tower 40b shown in FIGS. 1 to 4, the detection window 20 is the same as the detection windows 20a and 20b, and the detection agent 30 is the same as the detection agent 30a and 30b, the viewing window 22 corresponds to the viewing windows 22a and 22b, the removal agent 41 also corresponds to the removal agents 41a and 41b, and the processing gas storage space 42 corresponds to the processing gas storage spaces 42a and 42b, respectively. is there.

Here, in order to efficiently perform the adsorption removal treatment of the processing gas containing the harmful gas with the detoxifying agent, it is preferable to use the detoxifying agent formed into particles having an average diameter of 0.5 to 2 mm. By setting it as this particle diameter, the pressure loss of the process gas at the time of passing a detoxification tower can be suppressed, ensuring a sufficient contact area with process gas.
Here, when the processing gas passes between the particulate harmful agents, a predetermined drift occurs depending on the packing density of the harmful agents and the material of the inner wall surface of the harmful column. The line does not necessarily travel uniformly through the pesticide. For this reason, when the detection agent container is mounted in the removal tower so as to be completely buried inside the removal agent, for example, when the packing density of the removal agent in the vicinity thereof is high, a harmful gas detection window is used. A predetermined time lag occurs until the detection of the detection agent with the occurrence of discoloration of the detection agent from the viewing window is delayed.
In contrast, as in such detection container 23 to the present embodiment, since at least a part is exposed to the processing gas storage space 42, the detection agent 30 flows into the processing gas storage space 42 through the pipe 60 Immediate contact with harmful gases in the treated gas. This is because the process gas storage space 42 has a higher fluidity of the process gas than the packed bed of the particulate detoxifying agent, and easily diffuses uniformly.
Therefore, the presence of harmful gas that has flowed into the subsequent stage due to the breakthrough of the upstream detoxification tower is caused by the change of the detection agent 30 loaded in the subsequent detection window 20 to the color-detected detection agent 31 as shown in FIG. Detected quickly.

Further, in the detection window 20, at least a part of the detection agent 30 positioned on the outermost surface visible from the observation window 22 is directly exposed to the processing gas storage space 42 through the breathable detection agent container 23. Is preferred. Thereby, when harmful gas flows into the detoxification tower 40 and the color change reaction of the detection agent 30 occurs, it can be immediately observed from the viewing window 22. Therefore, in the present embodiment, as shown in FIG. 5B, the processing gas contact surface (gas contact surface) 27 of the viewing window 22 is provided so as to coincide with the inner wall surface position of the detoxification tower 40, and A gas inlet 26 for introducing harmful gas flowing through the detoxification tower 40 into the detection agent container 23 is formed adjacent to at least the gas contact surface 27 of the viewing window 22.
Here, “the gas contact surface 27 of the viewing window 22 coincides with the position of the inner wall surface of the detoxification tower 40” means that the structure of the mounting hole and mounting member for mounting the detection window 20 is assumed to be the detoxification tower 40. The inner wall surface of the detoxification tower 40 assumed when it is assumed that the detection window 20 is not provided, and the inner surface (gas contact surface 27) of the observation window 22 of the detection window 20 attached to the detoxification tower 40 It means that they are flush or cross each other, and includes the case where the radius of curvature of the abatement tower 40 and the viewing window 22 are different.

  As described above, the gas for introducing the processing gas to the position adjacent to the gas contact surface 27 of the observation window 22 by matching the gas contact surface 27 of the observation window 22 with the surface position of the inner wall surface of the detoxification tower 40. By providing the introduction port 26, the harmful gas that has flowed into the processing gas storage space 42 immediately changes the color of the detection agent 30 that is visible from the viewing window 22, so that it is possible to accurately detect the breakthrough of the previous detoxification tower. it can.

  In the detection window 20, the gas contact surface 27 of the observation window 22 may be provided closer to the center of the detoxification tower 40 than the inner wall surface position of the detoxification tower 40. With such a configuration, the contact property between the harmful gas that has flowed into the processing gas storage space 42 through the pipe 60 and the detection agent 30 that can be observed from the viewing window 22 is further improved. “The gas contact surface 27 of the viewing window 22 is provided closer to the center side of the detoxification tower 40 than the inner wall surface position of the detoxification tower 40” means that the viewing window is viewed from the flow direction of the processing gas. This means that at least a part of the 22 gas contact surfaces 27 is closer to the center of the detoxification tower 40 than the inner wall surface of the detoxification tower 40.

Further, by making the detection window 20 detachable from the detoxification tower 40, the detection window 20 filled with the detection agent 30 can be externally attached to the detoxification tower 40 even when the detoxification tower 40 is filled with the detoxification agent 41. It can be installed from above and has excellent handling properties.
Furthermore, when updating the discolored detection agent 30 that has detected breakthrough of the abatement tower in the previous stage, in particular, the gas contact with the viewing window 22 should not be misunderstood during the next detection. Although it is necessary to cleanly remove the discolored detection agent 31 attached to the surface 27, it is preferable that the detection window 20 be detachable from the detoxification tower 40 from the viewpoint of workability.

The viewing window 22 is made of a light transmissive material such as glass or acrylic resin. The shape of the viewing window 22 is not limited to the circular shape shown in FIG. In addition, the detection windows 20 may be provided at a plurality of locations in the circumferential direction of the detoxification tower 40, or may be a belt-like window shape extending over the entire side surface of the detoxification tower 40. By providing such a detection window 20, the viewing area from the observation window 22 is enlarged, and breakthrough of the abatement tower in the previous stage can be reliably detected.
Moreover, the presence or absence of discoloration of the detection agent 30 detected from the viewing window 22 may be confirmed by visual observation or may be observed by a commercially available color mark sensor.

<About hazardous gas>
The harmful gas that can be detoxified in the present invention is not particularly limited as long as a combination with a detoxifying agent that suitably detoxifies can be selected. For example, arsine, phosphine, silane, diborane or arsenic , A volatile inorganic hydride such as a hydride such as phosphorus or selenium, or a volatile inorganic halide obtained by substituting a part or all of hydrogen of the volatile inorganic hydride with a halogen atom, or the hydrogen is an alkyl group or an alkoxide Volatile organic compounds substituted in the group, or fluorine, chlorine, hydrogen fluoride, hydrogen chloride, chlorine trifluoride, boron trifluoride, boron trichloride, silicon tetrafluoride, silicon tetrachloride, titanium tetrachloride, aluminum chloride , Acidic gas such as germanium tetrafluoride or tungsten hexafluoride, ammonia, monomethylamine, dimethylamino , It can be exemplified basic gas such as trimethylamine or hydrazine.

<About the pesticide>
The detoxifying agent 41 used in the present invention is not particularly limited as long as it can detoxify the processing gas containing the harmful gas by a dry purification method. Specifically, for example, a detoxifying agent containing manganese dioxide, copper oxide or cupric hydroxide as a main component can purify volatile inorganic hydrides, and activated carbon has an alkali metal salt or alkaline earth metal salt of formic acid. The detoxifying agent impregnated with can remove volatile inorganic halides, and the detoxifying agent impregnated with manganese dioxide or copper oxide with a copper salt can purify basic gas. When the harmful gas is a mixed gas of two or more types, even if a harmful agent capable of purifying any harmful gas component is selected and used, the harmful gases that can purify each harmful gas component are mixed. It may be used.

<About detection agent>
The detection agent 30 is a compound different from the detoxifying agent, and various compounds are used depending on the type of harmful gas to be detected. In general, a substance that changes color when contacted with the harmful gas, for example, bismuth chloride, Litmus, cupric hydroxide, etc. are used. These discoloring substances are used in the form of a molded body such as a sphere or a cylinder having a diameter of about 1 to 10 mm, or such particles in order to secure the fluidity of the processing gas while improving the contact efficiency between the processing gas and the detection agent. It may be used by supporting it on a carrier such as silica gel or alumina having a diameter.
In addition, the average diameter of the pesticide and the detection agent is obtained by sampling a predetermined ratio of the total filling amount, and calculating the average value of the diameters by approximating each particle to a sphere by a commercially available image processing apparatus. Can do.

<About the abatement tower>
The abatement tower 40 is generally a cylindrical container made of a corrosion-resistant metal material or the like, but its cross-sectional shape and center line shape are not particularly limited. In the present embodiment, a cylindrical or rectangular cylindrical stainless steel container can be used.

It is a systematic diagram of the harmful gas elimination apparatus concerning an embodiment of the invention. It is a systematic diagram of the abatement apparatus with the first abatement tower removed. It is a systematic diagram of the abatement apparatus which attached the 1st abatement tower which updated the abatement agent and the detection agent. It is a systematic diagram of the abatement apparatus with the second abatement tower removed. It is a schematic diagram of the detection window concerning embodiment of this invention, (a) is a front view, (b) is the bb sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Detoxification apparatus 11 1st gas line 12 2nd gas line 13 Exhaust lines 15, 16 Four-way valve 20 Detection window 22 Viewing window 23 Detection agent container 30 Detection agent 40 Detoxification tower 41 Detoxification agent 42 Processing gas storage space 44 Removal Harmful gas storage 45 breakthrough line

Claims (4)

A detection window comprising a detection agent container loaded with a detection agent that changes color by contact with harmful gas and a viewing window for observing the color change of the detection agent is provided, and the harmful gas is adsorbed and removed. A detoxification tower filled with at least two types of detoxifying agents filled in order to detoxify the harmful gas introduced through the two or more types of detoxification towers,
The detection agent is a compound different from the detoxifying agent,
Inside the detoxification tower, a processing gas storage space is formed on the upstream side of the filled detoxifying agent with respect to the flow direction of the harmful gas passing therethrough,
At least a part of said detection container is, abatement apparatus characterized by being exposed to the treatment gas retention space. The at least part of the detection agent located on the outermost surface visible from the viewing window is directly exposed to the processing gas storage space through a breathable detection agent container. Abatement equipment. A gas introduction port for introducing a harmful gas flowing through the detoxification tower into the detection agent container and at least providing a processing gas contact surface (gas contact surface) of the viewing window coincides with an inner wall surface position of the detoxification tower, It is formed adjacent to the gas contact surface of the viewing window
The abatement apparatus according to claim 1 or 2, characterized in that. The abatement apparatus according to any one of claims 1 to 3, comprising at least first and second abatement towers arranged in series, wherein a processing gas containing a harmful gas is introduced.
A processing gas is introduced into the first abatement tower, the processing gas discharged from the first abatement tower is guided to the second abatement tower, and the processing gas discharged from the second abatement tower is A first gas line leading out of the system,
A processing gas is introduced into the second detoxification tower, the processing gas discharged from the second detoxification tower is guided to the first detoxification tower, and the processing gas discharged from the first detoxification tower is A second gas line leading out of the system;
A detoxifying device comprising switching means for switching the flow path of the processing gas to the first gas line or the second gas line.

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