Detoxification device and detoxification method for gas

Abstract

A detoxification device (100) that detoxifies a processing gas is provided with a decompression detoxification unit (1), an atmospheric pressure detoxification unit (2), and an exhaust pump (12). The decompression detoxification unit (1) includes a first inflow port (4i) and a first outflow port (14c). The atmospheric pressure detoxification unit (2) includes a second inflow port (16i) and a second outflow port (16o). The first outflow port (14c) communicates with an intake port (12i) of the exhaust pump (12), the second inflow port (16i) is connected to an exhaust port (12o) of the exhaust pump (12), and the exhaust pump (12) increases the pressure of the processing gas.　In the processing gas detoxification method according to the present invention the processing gas is detoxified in a reduced-pressure state, the pressure of the processing gas is increased to the atmospheric pressure, the processing gas is detoxified in the atmospheric-pressure state, and the processing gas is discharged.

Description

Gas detoxification device and method

[0001] The present invention relates to a gas abatement device and a gas abatement method.

[0002] In the electronics industry, which manufactures semiconductors, liquid crystals, etc., various film formation processes such as silicon oxide film CVD are used. For example, to form silicon-based thin films, silane-based gases, which are explosive and toxic, are mainly used. After being used in process equipment, process gases containing such silane-based gases are neutralized as exhaust gases in abatement equipment. In conventional abatement equipment, large amounts of diluting nitrogen gas are injected upstream of the abatement equipment to dilute explosive gases in the exhaust gases to below the explosion limit. For example, in a typical silicon oxynitride film CVD, SiH ４ / NH ３ / N ２ A mixed gas of O = 1 SLM / 10 SLM / 10 SLM is used, but SiH ４ Because the explosive range of flammable gas is 1.3% to 100%, the discharged process gas must be immediately diluted with nitrogen dilution gas by approximately 76 times. In addition to CVD processes, there are also processes that use hydrocarbon-based flammable gases, which necessarily require nitrogen dilution. Such dilution allows safe and reliable detoxification using conventional combustion or atmospheric pressure plasma pyrolysis devices. However, in atmospheric pressure detoxification devices that detoxify gases at atmospheric pressure, as the flow rate of flammable gas increases, the amount of nitrogen dilution gas required also increases, resulting in cost burdens and the enormous energy required to thermally decompose the large amount of gas. To solve this problem, reduced-pressure detoxification devices have been invented that reduce the amount of nitrogen dilution and can safely detoxify gases under reduced pressure.

[0003] Japanese Patent No. 4796733 Japanese Patent Application Laid-Open No. 2020-93237 WO2018 / 221067 WO2018 / 216446 Japanese Patent No. 7284546

[0004] Although the decompression detoxification system has the extremely effective advantage of being able to reduce the amount of nitrogen gas used for dilution, it also has the disadvantage of reducing the amount of ammonia (NH ３ However, there is a problem in that the removal properties of water-soluble gases such as HCl, HCl, and HCl are reduced.

[0005] In view of the above problems, an object of the present invention is to provide a detoxification apparatus and a detoxification method that can effectively remove the gas to be treated while reducing or significantly reducing the amount of nitrogen gas used for dilution.

[0006] The decontamination device of the present invention is a decontamination device for decontaminating a gas to be treated, and is characterized in that it comprises a reduced pressure decontamination section, an atmospheric pressure decontamination section, and an exhaust pump, the reduced pressure decontamination section having a first inlet port and a first outlet port, the atmospheric pressure decontamination section having a second inlet port and a second outlet port, the first outlet port communicating with an intake port of the exhaust pump, the second inlet port connected to an exhaust port of the exhaust pump, and the exhaust pump pressurizing the gas to be treated.

[0007] By using a detoxification device with this configuration, the gas to be treated can be introduced into the detoxification device under reduced pressure, and the gas to be treated treated in the reduced pressure detoxification section can be pressurized and introduced into the atmospheric pressure detoxification section for treatment, thereby making it possible to efficiently detoxify the gas to be treated.

[0008] Furthermore, in the abatement device of the present invention, in the above configuration, the reduced pressure abatement section has an inlet scrubber, a reaction chamber, and a water tank, the atmospheric pressure abatement section has an outlet scrubber, the water tank communicates with the inlet scrubber, the outlet of the inlet scrubber communicates with the inlet of the reaction chamber, the water tank stores treated water to be supplied to the inlet scrubber, and the first outlet port may be provided in the water tank.

[0009] By configuring the detoxification device in this way, the exhaust pump can also cool the treated water in the water tank.

[0010] Moreover, in the above-mentioned configuration, the abatement apparatus according to the present invention may further include a drainage pump, the water tank being in communication with a water intake port of the drainage pump, and the outlet scrubber being connected to the drainage port of the drainage pump.

[0011] By configuring the decontamination device in this manner, during normal operation the drainage pump supplies the treated water in the tank to the outlet scrubber side, and when the exhaust pump stops, the drainage pump can be used to exhaust the treated gas in the tank, making it possible to stop the decontamination device in a safe state.

[0012] Moreover, in the above-described configuration, the abatement apparatus according to the present invention may further include a circulation pipe, and the circulation pipe may connect the outlet scrubber with the inlet scrubber, the reaction chamber, and the water tank.

[0013] By using the abatement apparatus with this configuration, the circulation pipe can supply treated water on the atmospheric pressure abatement section side to the reduced pressure abatement section by utilizing the pressure difference between the reduced pressure abatement section and the atmospheric pressure abatement section.

[0014] Moreover, in the above-described configuration, the abatement device according to the present invention may further include a buffer tank, and the buffer tank may be in communication with the first inlet port.

[0015] By using a detoxification apparatus having such a configuration, it is possible to efficiently detoxify the gas to be treated even when the pressure fluctuation of the gas to be treated that is discharged is large, such as in an ALD process apparatus.

[0016] Furthermore, in the abatement device according to the present invention, in the above configuration, the reaction chamber may have a reactor body and a plasma generating means, and a plurality of cooling water ejectors arranged in a circumferential direction may be provided on an inner wall surface of the reactor body.

[0017] By using a detoxification device with such a configuration, it is possible to remove reaction products in the reaction chamber while suppressing a drop in plasma temperature.

[0018] Furthermore, in the above-described configuration, the detoxification device of the present invention may further include a pipe connecting the reduced pressure detoxification section and the atmospheric pressure detoxification section, and the pipe may be provided with an on-off valve and a check valve in series, with the check valve being located downstream of the on-off valve.

[0019] By combining the on-off valve and the check valve with such a configuration, airtightness on the pressure reducing side can be reliably ensured.

[0020] The detoxification method according to the present invention is characterized by comprising a decompression detoxification step of detoxifying a gas to be treated discharged from a gas generation source under reduced pressure, a pressurization step of pressurizing the gas to be treated to atmospheric pressure, an atmospheric pressure detoxification step of detoxifying the gas to be treated under atmospheric pressure, and a discharge step of discharging the gas to be treated.

[0021] By using the detoxification method having such a configuration, the gas to be treated can be detoxified efficiently.

[0022] Furthermore, in the decontamination method of the present invention, in the above configuration, the reduced pressure decontamination step may include a reduced pressure water spraying treatment step of spraying water onto the gas to be treated, and a heat treatment step of subjecting the gas to heat treatment using plasma, and the atmospheric pressure decontamination step may include an atmospheric pressure water spraying treatment step of spraying water onto the gas to be treated.

[0023] By using such a detoxification method, it is possible to effectively detoxify the gas to be treated by effectively utilizing the heat of the plasma, and then to effectively detoxify the reaction products and the like at atmospheric pressure.

[0024] According to the present invention, it is possible to provide a detoxification apparatus and a detoxification method that can effectively detoxify a gas to be treated while reducing or significantly reducing the amount of nitrogen gas used for dilution.

[0025] FIG. 1 is a schematic diagram showing the main configuration of the abatement apparatus 100 of embodiment 1. FIG. 2 is a partially enlarged view of the abatement apparatus 100 in the vicinity of the reaction chamber 5. FIG. 3 is a partially enlarged view showing the internal configuration of the reaction chamber 5, with FIGS. 3(A) and 3(B) showing vertical cross sections and FIG. 3(C) showing a horizontal cross section. FIG. 4 is a schematic diagram for explaining an experiment to verify the performance of the valve unit. FIG. 4(A) is a schematic diagram for explaining an experiment to verify the performance of the valve unit on the discharge side of the drainage pump 13, FIG. 4(B) is a schematic diagram for explaining an experiment to verify the performance of the valve unit on the discharge side of the exhaust pump 12, and FIG. 4(C) is a schematic diagram for explaining an experiment to verify the performance of the valve unit with respect to airtightness. FIG. 5 is a schematic diagram showing the main configuration of the abatement apparatus 100 of another embodiment.

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are not intended to limit the scope of the present invention. Furthermore, the same or similar components will be designated by the same reference numerals, and their description may be omitted.

[0027] Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," "same," "vertical," and "horizontal," as well as values ​​of length and angle (direction), pressure, etc., are not to be bound by strict meanings but are to be interpreted to include a range within which similar functions can be expected.

[0028] (Embodiment 1) <Apparatus Configuration> An embodiment of a detoxification apparatus 100 for a gas to be treated will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the main configuration of the detoxification apparatus 100 of embodiment 1. The detoxification apparatus 100 is preferably capable of detoxifying a gas (gas to be treated) containing harmful components (e.g., flammable gas) that is emitted from a gas generation source such as a film formation apparatus, but is not limited thereto. The detoxification apparatus 100 can be used to detoxify a gas (gas to be treated) containing harmful components that is emitted under reduced pressure from a gas generation source.

[0029] The detoxification device 100 has a reduced pressure detoxification section 1 (first detoxification section) and an atmospheric pressure detoxification section 2 (second detoxification section). The treatment pressure of the gas to be treated in the reduced pressure detoxification section 1 (first treatment pressure) is lower than the treatment pressure of the gas to be treated in the atmospheric pressure detoxification section 2 (second treatment pressure) ([first treatment pressure] < [second treatment pressure]). The reduced pressure detoxification section 1 performs detoxification treatment on the gas to be treated under a low pressure (reduced pressure) state.

[0030] The reduced pressure abatement section 1 and the atmospheric pressure abatement section 2 are connected by an exhaust pump 12 and a drainage pump 13. The exhaust pump 12 and the drainage pump 13 connect the reduced pressure abatement section 1 and the atmospheric pressure abatement section 2, and in that sense, they can also be interpreted as being located in a boundary area. During normal operation, the exhaust pump 12 and the drainage pump 13 are always operating. Note that multiple exhaust pumps 12 and drainage pumps 13 may be provided.

[0031] The reduced pressure abatement section 1 has an inlet scrubber 4, a reaction chamber 5, and a water tank 6 (tank section), while the atmospheric pressure abatement section 2 has an outlet scrubber 16. A gas outlet 4b of the inlet scrubber 4 and an inlet 5c of the reaction chamber 5 are connected by a pipe 11. The gas to be treated is delivered from a gas generation source by a vacuum pump 3 and introduced into the inlet scrubber 4 via a pipe 10 (inlet pipe) connected to a gas inlet 4i (first inlet port) of the inlet scrubber 4. The inlet scrubber 4 treats the gas to be treated under reduced pressure. The number of inlet scrubbers 4, reaction chamber 5, and outlet scrubber 16 is not limited to one, and multiple units may be provided.

[0032] In addition, a valve V1 (open / close valve) and a check valve CV1 downstream of the valve V1 are provided in the pipe 10b branching off from the pipe 10 and extending to the atmospheric pressure abatement section 2, and the valve V1 is maintained in a normally closed state. If an abnormality occurs in the abatement device 100, the valve V1 can be opened to discharge the gas to be treated outside the abatement device 100.

[0033] The water tank 6 is provided with a water storage section 6a (pressure-reduced water storage section) in which treated water (circulated water) is stored, and an internal space 6s above it. The treated water in the water storage section 6a is sucked in by a circulation pump 8 through a pipe 9b and supplied to the inlet scrubber 4 through a pipe 9a. The water tank 6 receives the treated water supplied to the inlet scrubber 4. A partition wall 7 is provided within the water tank 6, and the lower end of the partition wall 7 extends into the treated water stored in the water storage section 6a. The treated water in the water tank 6 and the partition wall 7 separate the internal space 6s into a first internal space 6s1 and a second internal space 6s2.

[0034] The lower end of the inlet scrubber 4 is connected to a first internal space 6s1 of the internal space 6s of the water tank 6, and treated water sprayed by an ejector 4a (spray nozzle) provided in the inlet scrubber 4 returns to the water tank 6 from the lower end of the inlet scrubber 4. The treated water is circulated between the inlet scrubber 4 and the water tank 6. Inside the inlet scrubber 4, treated water is sprayed onto the gas to be treated under reduced pressure, and detoxification treatment such as removal of water-soluble substances and dust is carried out.

[0035] The reaction chamber 5 can perform heat treatment on harmful components in the gas to be treated. Specifically, the reaction chamber 5 can decompose and / or react the harmful components in the gas to be treated that flows in from the inlet 5c via the pipe 11. For example, as will be described later, the reaction chamber 5 generates plasma in a reduced pressure state to thermally detoxify the gas to be treated.

[0036] Alternatively, the treated water may be supplied to the reaction chamber 5 by a circulation pump 8. The treated water is supplied to the reaction chamber 5 via a pipe 9c branched from the pipe 9a, and flows into the water tank 6 from the lower end of the reaction chamber 5 which communicates with the second internal space 6s2 of the internal space 6s. The treated water is circulated between the reaction chamber 5 and the water tank 6.

[0037] The first internal space 6s1 and the second internal space 6s2 of the water tank 6 are separated by the partition wall 7 and the treated water, which prevents the gas to be treated that flows from the reaction chamber 5 into the water tank 6 from flowing back toward the inlet scrubber 4. Similarly, the gas to be treated flows into the water tank 6 at the lower end of the inlet scrubber 4, and is prevented from flowing directly into the water tank 6 at the lower end of the reaction chamber 5.

[0038] A pipe 14a communicates with an exhaust port 14c (first outlet port) located above the surface of the treated water in the water tank 6, and is connected to an intake port 12i (intake port) of the exhaust pump 12. One end of the pipe 14b is connected to an exhaust port 12o (exhaust port) of the exhaust pump 12. The other end of the pipe 14b is connected to a gas inlet port 16i (second inlet port) of the outlet scrubber 16. The treated gas flowing into the water tank 6 flows into the exhaust pump 12 via the pipe 14a. The exhaust pump 12 does not require a dilution gas to deliver the treated gas to the outlet scrubber 16; it can pressurize the treated gas itself to atmospheric pressure (second treatment pressure) without dilution and deliver it to the gas inlet port 16i of the outlet scrubber 16 via the pipe 14b. The exhaust pump 12 also draws in the treated gas from the second internal space 6s2 above the water tank 6, thereby maintaining the reduced pressure decompression abatement unit 1. The exhaust pump 12 also has the effect of cooling the treated water in the water tank 6 because it removes the heat of vaporization when the treated water in the water tank 6 is vaporized.

[0039] In addition, a pipe 15a is connected to the water tub 6, and the pipe 15a is connected to the suction port 13i (water intake port) of the drainage pump 13. A pipe 15b, which is connected to the discharge port 13o (drainage port) of the drainage pump 13, is connected to the outlet scrubber 16. The suction side end (water intake port 15c) of the pipe 15a is located at a predetermined height h from the bottom surface of the water tub 6. The predetermined height h is equal to the height of the upper surface 6f of the water storage portion 6a of the water tub 6. Therefore, the height from the bottom surface of the water tub 6 to the lower end of the partition wall 7 is smaller than h, and the height from the bottom surface of the water tub 6 to the exhaust port 14c is greater than h.

[0040] Pipe 14b is provided with valve V2 (on-off valve), and pipe 15b is provided with valve V3 (on-off valve). Valves V2 and V3 are normally open and can be closed in the event of an abnormality. Pipe 14b is provided with check valve CV2 downstream of valve V2, and pipe 15b is provided with check valve CV3 downstream of valve V3 to prevent backflow of the treated gas and treated water from the outlet scrubber 16.

[0041] The outlet scrubber 16 has a water reservoir 16a (atmospheric pressure water reservoir) capable of storing treated water. The outlet end of the pipe 15b is connected to the water reservoir 16a, and the gas inlet 16i is located above the water reservoir 16a. The outlet scrubber 16 is installed independently of the water tank 6, but is connected to the water tank 6 by an exhaust pump 12 and a drainage pump 13. The outlet scrubber 16 may have a drainage port (not shown) so that treated water can be drained to maintain a constant water level in the water reservoir 16a.

[0042] A pipe 18 (water supply pipe) is connected to the outlet scrubber 16, and treated water is supplied to the inside of the outlet scrubber 16 through the pipe 18. The treated water is sprayed at atmospheric pressure from a spray nozzle 16b (spray nozzle) connected to the end of the pipe 18 onto the gas to be treated introduced into the outlet scrubber 16, and detoxification treatment such as removal of water-soluble substances and dust is performed. Since the inside of the outlet scrubber 16 is at atmospheric pressure, NH ３ It can remove water-soluble gases such as ammonia.

[0043] One end of a pipe 19 (exhaust pipe) is connected to an exhaust port 16o (second outlet port) of the outlet scrubber 16, and the treated gas that has flowed into the outlet scrubber 16 is released into the atmosphere via the pipe 19. Note that a blower (air blower) may be connected to the other end of the pipe 19 to release the treated gas into the atmosphere. When a blower is provided, strictly speaking, the pressure inside the pipe 19 located upstream of the blower will be negative compared to atmospheric pressure, but in this specification, the upstream side of the blower for releasing gas into the atmosphere is also considered to be at atmospheric pressure.

[0044] A pipe 29 (purge pipe) having a valve V4 (on-off valve) may be connected to the water tank 6, so that the water tank 6 can be purged with an inert gas such as nitrogen. The valve V4 is normally closed, but for maintenance of the abatement apparatus 100, the valve V4 can be opened to replace the air inside the abatement apparatus 100 with an inert gas. A check valve CV4 is preferably provided on the inert gas supply side of the valve V4. The valve V4 may also be configured so that it can be used as a pressure relief port when the abatement apparatus 100 is stopped, and a check valve CV4 may preferably be provided downstream of the valve V4.

[0045] A necessary amount of treated water can be supplied to the water tank 6 via a pipe 21 (water supply pipe). When the amount of treated water decreases due to evaporation or the like, treated water can be replenished to the water tank 6 from the pipe 21. The pipe 21 may merge with the pipe 9a, and treated water may be supplied to the water tank 6 via the pipe 21 and the pipe 9a.

[0046] As described above, valves V (valves V1, V2, V3, V4) and check valves CV (check valves CV1, CV2, CV3, CV4) are arranged in series in the piping connecting the reduced pressure atmosphere and the atmosphere, and check valve CV is arranged downstream of valve V. Even if valve V opens in an emergency (or abnormality), check valve CV can physically prevent backflow of fluid. Valve V is an automatic valve (torque valve) that performs torque operation in response to a signal, and can control its opening and closing. Even if dust contained in the fluid (exhaust gas or wastewater) adheres to valve V, it is possible to seal without trapping the dust. Valve V is arranged upstream, i.e., on the side where there is a higher risk of dust adhesion.

[0047] On the other hand, the check valve CV has an operating principle that is completely different from that of the automatic valve V. It is a physical valve that does not rely on signal operation, and malfunctions due to signal problems will not occur. However, there is a risk of dust and other particles getting trapped in the check valve CV. Therefore, by placing the check valve CV downstream of the valve V, that is, after the dust has passed through the valve V, even if dust that may adhere is contained in the fluid, the risk of the dust adhering to the check valve CV can be reduced. The backflow prevention performance of a valve unit that combines the valve V (opening / closing valve) and the check valve CV will be described later.

[0048] 2 shows a partially enlarged view of the detoxification device 100 near the reaction chamber 5. As described above, the exhaust pump 12 and the drainage pump 13 are connected to the water tank 6. The exhaust pump 12 is connected to a pipe 14a, which is connected to an exhaust port 14c (first outlet port) provided above the water surface and communicates with the second internal space 6s2. The exhaust pump 12 can exhaust the gas to be treated within the second internal space 6s2 above the water surface. Note that the exhaust pump 12 and the drainage pump 13 can preferably be water-sealed pumps. The use of a water-sealed pump makes it possible to discharge both gases such as the gas to be treated and treated water.

[0049] Pipe 15a is connected to drainage pump 13, and pipe 15a is provided with water intake port 15c at a predetermined height h from the bottom of water tank 6. Drainage pump 13 can maintain the water level in water tank 6 at a constant height h. Note that water tank 6 may be provided with a water level gauge so that water is supplied from pipe 21 when the water level falls below h by a predetermined amount.

[0050] The pipes 14a and 15a are connected by a bypass pipe 20, and a valve V6 (on / off valve) is provided on the bypass pipe 20. The valve V6 is normally closed, and the gas to be treated does not flow between the pipes 14a and 15a via the bypass pipe 20. The pipe 14a is provided with a valve V5 (on / off valve) and a valve V2, and the pipe 15a is provided with a valve V7 (on / off valve) and a valve V3. The valves V5, V2, V7, and V3 are normally open, allowing the exhaust pump 12 and the drainage pump 13 to exhaust and discharge the gas.

[0051] For example, in a configuration in which a single exhaust pump exhausts the gas to be treated inside the water tank 6, if the exhaust pump breaks down or becomes clogged with powder, there is a risk of a sudden increase in pressure inside the water tank 6. In this case, even if the abatement device is stopped in an emergency, the harmful gas will remain trapped inside, and subsequent recovery work will not be easy.

[0052] However, in the present detoxification apparatus 100, if one of the exhaust pump 12 and the drainage pump 13 stops due to a malfunction or the like, valve V6 can be opened and the gas to be treated can be discharged by the other pump, thereby avoiding a sudden increase in pressure in the decompression and detoxification unit 1. As a result, the detoxification apparatus 100 can be safely shut down. For example, if the exhaust pump 12 stops, valves V5 and V2 can be closed, valve V6 can be opened, and valves V7 and V3 can be maintained open, allowing the gas to be discharged by the drainage pump 13. Note that, as described above, employing a water-sealed pump as the drainage pump 13 also enables the gas to be discharged. In this way, the drainage pump 13, while having a different function from the exhaust pump 12, can address the risk of a sudden increase in pressure in the water tank 6, etc.

[0053] When the exhaust pump 13 stops, the valves V7 and V3 are closed, the valve V6 is opened, and the valves V5 and V2 remain open, so that the gas to be treated can be exhausted by the exhaust pump 12.

[0054] For verification, the exhaust characteristics of one of the exhaust pump 12 and the drainage pump 13 were investigated. First, in Fig. 2, the pressure inside the water tank 6 was 12.7 kPa when exhausting at a flow rate of 45 SLM by the exhaust pump 12 and draining at a flow rate of 12 L / min by the drainage pump 13 were simultaneously performed with the valve V6 of the bypass piping 20 closed. ４ If it contains SiH ４ From the viewpoint of reactivity, it is assumed that the pressure in the reduced pressure abatement section 1 will be kept below 33 kPa.

[0055] Next, the valve V6 of the bypass pipe 20 was opened, and the pressure inside the water tank 6 was measured when exhaust was performed at a flow rate of 45 SLM using only the exhaust pump 12, or when drainage was performed at a flow rate of 12 L / min using only the drainage pump 13. The result was 12.7 kPa. However, the valves before and after the pump that was not operating were closed.

[0056] In this way, it was confirmed that even when only one of the exhaust pump 12 and the drainage pump 13 is operating, the pressure in the decompression and abatement section 1 is lower than expected, and the same pressure can be maintained as when both the exhaust pump 12 and the drainage pump 13 are operating. In this way, by providing the bypass piping 20 and using the exhaust pump 12 and the drainage pump 13 having different functions, the abatement device 100 can be maintained in a safe state even when one of the pumps stops due to a malfunction or the like.

[0057] It is also possible to provide a pipe 29 for supplying a dilution gas to the water tank 6, and to supply, as a dilution gas, for example, nitrogen gas to the water tank 6 via a valve V4. Valve V4 is normally closed, and if one of the pumps fails, valve V4 can be opened to purge (dilute) the inside of the water tank 6 with nitrogen gas while continuing to evacuate with the other pump, allowing the abatement device 100 to be stopped in a safe state.

[0058] <Plasma Treatment Apparatus> Fig. 2 also shows a schematic configuration example of an abatement apparatus 100 that employs a plasma treatment apparatus as the reaction chamber 5. The reaction chamber 5 is capable of generating plasma (plasma jet) under reduced pressure. The reaction chamber 5 is equipped with a straight-tube reactor body 5a with both ends open and a plasma generation means 5b. A known device can be used as the plasma generation means 5b.

[0059] A plasma generating means 5b is provided at the upper end of the reactor body 5a, and the lower end (outlet bottom 5o) of the reactor body 5a communicates with the second internal space 6s2 of the water tank 6. The interior surrounded by the reactor body 5a constitutes a reaction space RS. The pressure of the reaction space RS of the reaction chamber 5 is, for example, in the range of 133 Pa to 93.1 kPa, preferably 6.65 kPa to 53.2 kPa, and more preferably in the range of 13.3±5.32 kPa.

[0060] A plasma jet torch 50 employing DC arc discharge can be preferably used as the plasma generating means 5b. The plasma jet torch 50 has a torch body 51, an anode 52 is provided at the tip of the torch body 51, and the space surrounded by the anode 52 constitutes a plasma generating section 54. A rod-shaped cathode 53 is provided inside the anode 52. An insulator is provided between the anode 52 and the cathode 53 to prevent electrical short-circuiting. The plasma generating means 5b has a power supply 56 that supplies DC power to the anode 52 and the cathode 53.

[0061] The torch body 51 has a working gas supply passage 55 communicating with the plasma generating section 54 to supply a working gas, which is a fluid for generating plasma, to the plasma generating section 54. The fluid for generating plasma can be at least one selected from the group consisting of nitrogen, oxygen, argon, helium, and water, and is supplied to the plasma jet torch 50 through the working gas supply port 55. A pipe 55a connected to the working gas supply port 55 is provided with a flow rate control means 55b, such as a mass flow controller, for controlling the flow rate of the working gas.

[0062] Plasma can be generated by supplying a working gas to the plasma generating unit 54 and applying a predetermined discharge voltage to the anode 52 and cathode 53 to generate an arc discharge. An opening, or nozzle 57, is provided at the tip of the anode 52, and the generated plasma is emitted from the nozzle 57 into the reaction space RS to form a plasma jet P. The energy of the plasma jet P can decompose or react harmful components in the gas to be treated.

[0063] Since the gas to be treated can be treated under reduced pressure, nitrogen gas for dilution is not required, or only a very small amount is required, inside the vacuum pump 3 or downstream of the vacuum pump 3. Therefore, almost all of the heat from the plasma jet P can be used directly for decomposing and reacting the gas to be treated.

[0064] Note that water may be supplied to the inside of the reaction chamber 5 for the purpose of dissolving the reaction product or cooling the reactor main body 5a. Figure 3 is a partially enlarged view showing the internal configuration of the reaction chamber 5, with Figures 3(A) and 3(B) showing vertical cross sections and Figure 3(C) showing a horizontal cross section. The reaction chamber 5 shown in Figures 3(B) and 3(C) is a modified version of the reaction chamber 5 shown in Figure 3(A).

[0065] The reaction chamber 5 shown in FIG. 3(A) has an inner cylinder 58 therein. The inner cylinder 58 has a cylindrical inner wall 58a and a bottom 58b, and further has an opening 58c at its upper end. The space surrounded by the inner wall 58a, the bottom 58b, and the reactor main body 5a (particularly the inner wall surface 5s of the reactor main body 5a) constitutes a water reservoir 58d. The reactor main body 5a is provided with a flow path 5d communicating with the water reservoir 58d. Treated water to be supplied to the reaction chamber 5 is supplied to the flow path 5d by a circulation pump 8 through a pipe (not shown) branching from the pipe 9a. The flow rate of the treated water can be adjusted by a valve (not shown) and monitored by a flow meter. Treated water from the water tank 6 is supplied to the water reservoir 58d via the flow path 5d by the circulation pump 8. The treated water overflows from the opening 58c of the inner cylinder 58, flows along the inner wall 58a, and forms a water wall 5w. The water wall 5w dissolves the reaction products and cools the reactor body 5a. The inside of the reactor body 5a is under reduced pressure, lowering the boiling point of the treated water, promoting boiling of the treated water, and the heat of vaporization of the treated water removes heat from the surroundings, increasing the cooling effect. The flow rate of the treated water supplied to the flow path 5d can be adjusted by a valve (not shown) and may be monitored by a flow meter.

[0066] On the other hand, Figures 3(B) and 3(C) show different embodiments of the reaction chamber 5. Figures 3(B) and 3(C) are vertical and horizontal cross-sectional views schematically illustrating a reaction chamber 5 in which treated water can be supplied to the inner wall surface 5s of the reactor body 5a without the inner cylinder 58. In the configuration in which the inner cylinder 58 is provided inside the reactor body 5a as shown in Figure 3(A), the water wall 5w formed in the reactor body 5a is positioned closer to the plasma jet P. As a result, the treated water is more likely to absorb the thermal energy of the plasma jet P, reducing the effectiveness of the plasma jet P in decomposing harmful components in the treated gas. However, in the configurations shown in Figures 3(B) and 3(C), the water wall 5w of the treated water is prevented from approaching the plasma jet P, thereby reducing the loss of thermal energy from the plasma jet P due to the heat of vaporization of the treated water.

[0067] As shown in FIG. 3(B), treated water is supplied as cooling water into the reaction chamber 5 through a flow path 5e. A jet 5f (cooling water jet) is provided at the end of the flow path 5e. Also, as shown in FIG. 3(C), a plurality of jets 5f are provided and arranged in the same circumferential direction along the inner wall surface 5s. The treated water discharged from the jets 5f flows in the same direction along the inner wall surface 5s, generating a swirling flow of the treated water. The jets 5f generate a swirling flow and have the function of cooling the inner wall surface 5s with the swirling flow. The jets 5f are preferably arranged so that a water flow is formed over the entire inner wall surface 5s. The treated water is supplied to the flow path 5e by a circulation pump 8, and the flow rate can be adjusted by a valve (not shown) and may be monitored by a flow meter.

[0068] The reaction chamber 5 ２ To confirm that O can be decomposed, ２ The decomposition rate (DRE) of N was investigated. ２ The gas to be treated containing O is SiH ４ / NH ３ / N ２ O / N ２ A mixed gas of 1 SLM / 10 SLM / 10 SLM / 179 SLM was used. The power supplied to the plasma jet torch 50 in the reaction chamber 5 was 15 kW, and the flow rate of nitrogen gas as the working gas was 80 SLM.

[0069] In the reaction chamber 5 shown in FIG. 3A, N ２ The decomposition rate of O exceeded 90%, while that of N under reduced pressure of 10 kPa was ２ The decomposition rate of O fell to a value below 85%. It is thought that under reduced pressure, the treated water boils at a low temperature, and the heat of vaporization takes thermal energy from the surroundings, causing the plasma temperature to drop and the reaction rate to drop. On the other hand, in the reaction chamber 5 shown in Figure 3(B), N ２ The decomposition rate of O exceeded 90%. It is believed that the improvement in decomposition characteristics was achieved by suppressing the decrease in plasma temperature.

[0070] <Performance Evaluation of Valve Unit> The performance of a valve unit combining a valve V (on-off valve) and a check valve CV was verified. Fig. 4 is a schematic diagram for explaining an experiment for verifying the performance of the valve unit. Fig. 4(A) is a schematic diagram for explaining an experiment for verifying the performance of the valve unit on the discharge side of the drainage pump 13, Fig. 4(B) is a schematic diagram for explaining the performance of the valve unit on the discharge side of the exhaust pump 12, and Fig. 4(C) is a schematic diagram for explaining an experiment for verifying the performance of the valve unit with respect to airtightness.

[0071] <Performance evaluation of the drainage pump valve unit> For verification, a water tank 6' was prepared, which was located on the exhaust pump 12 and drainage pump 13 side of the partition wall 7 of the water tank 6 and corresponded to a configuration in which the reaction chamber 5 was not installed. The water tank 6' was provided with a pipe 29, which allowed nitrogen gas to be introduced via a valve V4, and a concentration meter CM and a pressure gauge PG for measuring the gas concentration.

[0072] As shown in Figure 4(A), the water tank 6' is connected to an outlet scrubber 16 by pipes 15a and 15b (hereinafter sometimes referred to as pipe 15). Similar to the water tank 6 shown in Figure 2, the pipe 15 is connected to a drainage pump 13, and a valve V3 and a check valve CV3 are arranged in this order downstream of the drainage pump 13.

[0073] The following describes a verification experiment for the performance of the valve unit composed of valve V3 and check valve CV3. Treated water was stored in water tank 6' up to a height h determined by the position of water intake 15c at the end of pipe 15a. Concentration meter CM measures the oxygen concentration in the upper region of the treated water. Valve V4 was opened, and nitrogen was introduced through pipe 29 until the oxygen concentration in the upper region of the treated water reached 0.5% or less. Then, valve V4 was closed. Treated water was supplied to water tank 6' at a rate of 8 L / min through water supply pipe 21, and the treated water was discharged to outlet scrubber 16 by drainage pump 13. At this time, the pressure in water tank 6' was 8.5 to 9.5 kPa, and the oxygen concentration was 0.5%. With valve V3 open, the water supply from pipe 21 was stopped, and the drainage pump 13 was stopped. The changes in pressure and oxygen concentration in water tank 6' over time were investigated. The pressure was 9.2 kPa and the oxygen concentration was 0.5%, and no tendency for either to increase over time was observed. From the above, it was confirmed that the check valve CV3 prevented backflow and maintained the reduced pressure state of the water tank 6'.

[0074] To investigate the effect of dust in the treated water, simulated powder was mixed into the treated water in water tank 6', and the water supply from pipe 21 and the operation of drainage pump 13 were continued for five hours. After that, with valve V3 left open, the water supply from pipe 21 was stopped and drainage pump 13 was stopped. No increase in pressure or oxygen concentration was observed in water tank 6', and it was confirmed that check valve CV3 prevented backflow and maintained the reduced pressure state of water tank 6'. No adhesion of powder to check valve CV3 was observed.

[0075] Additionally, to confirm the effectiveness of arranging valve V3 and check valve CV3 in order from upstream, the positions of valve V3 and check valve CV3 were reversed, and check valve CV3 and valve V3 were arranged in order from upstream to downstream, and the impact of dust in the treated water was investigated. As described above, powder was mixed into the treatment water, and the water supply from pipe 21 and the operation of drainage pump 13 were continued for five hours. After that, with valve V3 left open, the water supply from pipe 21 was stopped, and drainage pump 13 was stopped. Although no increase in pressure or oxygen concentration was observed in water tank 6', it was confirmed that powder had partially adhered to check valve CV3. Therefore, there was concern that long-term use could result in inadequate closing operation and backflow prevention due to dust adhesion to check valve CV3.

[0076] To verify the effects of long-term use, a verification experiment was conducted for 20 days, for a total of 100 hours, using treated water containing powder and operating the water supply from the pipe 21 and the drainage pump 13 for 5 hours a day. After that, the water supply from the pipe 21 was stopped and the drainage pump 13 was stopped while keeping the valve V3 open. The changes in pressure and oxygen concentration over time were investigated, and an increase in the pressure and oxygen concentration was confirmed. After 30 minutes, the pressure reached 101 kPa and the oxygen concentration reached 18%, confirming that air was flowing backward through the check valve CV3. The above results indicate that, from the perspective of long-term operation of the abatement system 100, the valve V3 and the check valve CV3 should be arranged in order from upstream to downstream.

[0077] <Performance Evaluation of Valve Unit for Exhaust Pump> As shown in Fig. 4(B), the water tank 6' is connected to the outlet scrubber 16 by the pipe 14 (pipes 14a and 14b). As with the water tank 6 shown in Fig. 2, the pipe 14 is connected to the exhaust pump 12, and the valve V2 and the check valve CV2 are arranged in this order downstream of the exhaust pump 12.

[0078] Valve V2 was opened, valve V4 was opened, and nitrogen was introduced through pipe 29 at a flow rate of 20 SLM. The exhaust pump 12 then exhausted the water to the outlet scrubber 16 through pipe 14. Under this condition, the pressure and oxygen concentration in the region above the treated water in tank 6' were measured. The pressure was 10.2 to 10.7 kPa, and the oxygen concentration was 0.5%. Subsequently, valve V4 was closed while valve V2 was left open, the nitrogen supply was stopped, and the exhaust pump 12 was stopped. The changes in the pressure and oxygen concentration in tank 6' over time were then investigated. The results showed that the pressure remained at 10.6 kPa and the oxygen concentration remained at 0.5%, with no increase observed. This confirmed that the check valve CV2 alone was sufficient to prevent gas backflow and maintain the reduced pressure state in tank 6'.

[0079] If the valve V2 is located on the reduced pressure side and the check valve CV2 is located on the atmospheric pressure side (the outlet scrubber 16 side), when the exhaust pump 12 stops, the upstream side of the check valve CV2 is in a reduced pressure state and the downstream side is in an atmospheric pressure state, but both the upstream side and downstream side of the valve V2 are in a reduced pressure state. Therefore, there is no risk that the valve body of the valve V2 will be deformed due to the pressure difference.

[0080] On the other hand, if the check valve CV2 is located on the pressure reduction side and the valve V2 on the atmospheric pressure side (the outlet scrubber 16 side), when the exhaust pump 12 stops, the upstream side of the valve V2 will be in a reduced pressure state and the downstream side will be in an atmospheric pressure state, and a pressure difference will be applied to the valve disc of the valve V2, which may cause the valve disc to deform. Therefore, it is necessary to install the valve V2 on the pressure reduction side and the check valve CV2 on the atmospheric pressure side.

[0081] 4(C), in order to evaluate the performance of the valve unit, an airtight chamber 25 was prepared, and a valve V0 and a check valve CV0 were connected in series to a pipe 26 connected to the chamber 25. The chamber 25 was provided with an inlet port 27 and an exhaust port 28, as well as a concentration meter CM for measuring the gas concentration and a pressure gauge PG.

[0082] With valve V0 closed, nitrogen was flowing through inlet port 27, and the chamber 25 was evacuated by a vacuum pump (not shown) connected to exhaust port 28 until the oxygen concentration reached 0.5% or less. The oxygen concentration in chamber 25 was 0.5%, and the pressure was 8.5 to 9.5 kPa. Valve V27 of inlet port 27 was then closed to stop the supply of nitrogen, valve V28 of exhaust port 28 was closed, and the vacuum pump was stopped. Valve V0 was then opened, and chamber 25 was left in a reduced pressure state, and the changes in oxygen concentration and pressure over time were investigated. As a result, the pressure remained at 9.1 kPa, the oxygen concentration remained at 0.5%, and no increase in the oxygen concentration was observed.

[0083] By arranging the valve V0 on the reduced pressure side and the check valve CV0 on the atmospheric pressure side, the upstream side of the check valve CV0 is in a reduced pressure state and the downstream side is at atmospheric pressure, resulting in a large pressure difference. However, both the upstream and downstream sides of the valve V0 are in a reduced pressure state, and the valve body of the valve V0 will not deform. On the other hand, if the check valve CV0 is arranged on the reduced pressure side and the valve V0 on the atmospheric pressure side, the upstream side of the valve V0 is in a reduced pressure state and the downstream side is at atmospheric pressure. As a result, a large pressure difference is applied to the valve body of the valve V0, increasing the risk of the valve body deforming. Therefore, arranging the valve V0 on the upstream reduced pressure side and the check valve CV0 on the downstream atmospheric pressure side contributes to maintaining safety. For example, as shown in FIG. 1, in a valve unit consisting of a valve V1 and a check valve CV1 installed in a pipe 10b, the valve V1 is arranged on the upstream reduced pressure side and the check valve CV1 is arranged on the downstream atmospheric pressure side.

[0084] As described above, in any of the piping connecting the reduced pressure side (reduced pressure abatement section 1) and the atmospheric pressure side (atmospheric pressure abatement section 2), the valve unit used has a configuration in which valve V (opening / closing valve) is placed on the reduced pressure side and check valve CV is placed on the atmospheric pressure side, thereby ensuring reliable airtightness on the reduced pressure side.

[0085] <Detoxification Method> The detoxification process for the gas to be treated will be described below. Step 1 (Gas Introduction) The gas to be treated discharged from the gas generation source is introduced under reduced pressure into the reduced-pressure detoxification unit 1. Specifically, the gas to be treated is introduced into the inlet scrubber 4 via the pipe 10 and the gas inlet 4i.

[0086] Step 2 (reduced pressure detoxification: reduced pressure water spray treatment) In the inlet scrubber 4, the treated water supplied into the inlet scrubber 4 via the pipe 9a is released into the gas to be treated from the ejector 4a, adsorbs foreign matter and water-soluble substances contained in the gas to be treated, and falls into the water tank 6. The gas to be treated treated in the inlet scrubber 4 moves from the inlet scrubber 4 to the reaction chamber 5 via the pipe 11.

[0087] Step 3 (reduced pressure detoxification: reduced pressure heat treatment) The gas to be treated is introduced into the reaction chamber 5 under reduced pressure. In the reaction chamber 5, heat treatment is performed using plasma, and harmful components contained in the gas to be treated are thermally decomposed. In addition, reaction products are removed by treated water sprayed into the reaction chamber 5. Thereafter, the gas to be treated flows into the water tank 6 from the bottom end of the reaction chamber 5, and the treated water is collected in the water tank 6.

[0088] Step 4 (Pressurization) The gas to be treated is pressurized to atmospheric pressure by the exhaust pump 12 and introduced into the atmospheric pressure abatement section 2, specifically the outlet scrubber 16. The exhaust pump 12 is capable of pressurizing the gas to be treated without diluting it (undiluted).

[0089] Step 5 (Atmospheric Pressure Detoxification: Atmospheric Pressure Water Spray Treatment) In the outlet scrubber 16, treated water is sprayed from the sprayer 16b onto the gas to be treated. Water-soluble substances, dust, etc. in the gas to be treated are removed. The pressure of the gas to be treated is increased by the exhaust pump 12, and the molecular density of the gas is increased, so the detoxification efficiency in the outlet scrubber 16 is improved. For example, NH ３ The amount of water-soluble components such as ammonia dissolved in the gas is reduced under reduced pressure, and the removal characteristics of the water-soluble gas are deteriorated, but the removal characteristics can be improved by treating the gas under atmospheric pressure. Note that when a dilution gas is added to the gas to be treated and the pressure is increased to atmospheric pressure as in conventional exhaust pumps, the partial pressure of the water-soluble components is reduced, and the removal characteristics are therefore reduced compared to when the gas to be treated is pressurized without dilution.

[0090] Step 6 (Discharge) The treated gas is discharged from the outlet scrubber 16 and discharged to the outside of the abatement device 100 (or to the atmosphere) via the pipe 19 .

[0091] (Embodiment 2) In Embodiment 1, in the reduced pressure abatement section 1, treated water is circulated by the circulation pump 8 and supplied to the inlet scrubber 4 and the reaction chamber 5. However, depending on the temperature of the treated water, the treated water may evaporate near the suction port of the circulation pump 8, resulting in poor circulation. The abatement device 100 of Embodiment 2 utilizes a pressure difference to supply treated water from the outlet scrubber 16 of the atmospheric pressure abatement section 2 to the reduced pressure abatement section 1, thereby making it possible to eliminate the need for the circulation pump 8 of the reduced pressure abatement section 1.

[0092] FIG. 5 is a schematic diagram showing the main components of the abatement apparatus 100 of the second embodiment. As shown in FIG. 5, the circulation pipe 22 connects the atmospheric pressure abatement section 2 and the reduced pressure abatement section 1. One end (water intake end 22i) of the circulation pipe 22 is connected to the water reservoir 16a of the outlet scrubber 16. The other end (discharge end 22o) of the circulation pipe 22, specifically the ends (discharge end 22o) of the circulation pipes 22a and 22b branching from the circulation pipe 22, are connected to the reaction chamber 5 (e.g., flow path 5d or flow path 5e) and the inlet scrubber 4 (e.g., ejector 4a). The circulation pipe 22 communicates with the water reservoir 16a of the outlet scrubber 16, the inlet scrubber 4, and the reaction chamber 5, and can supply treated water to the inlet scrubber 4 and the reaction chamber 5. The circulation pipes 22a and 22b are provided with valves and flow meters to adjust the flow rate of the treated water. The end (drainage end 22o) of the circulation pipe 22c branched off from the circulation pipe 22 may be connected to the water tank 6. A valve and a flow meter may be provided on the circulation pipe 22c to adjust the total flow rate of the treated water flowing through the circulation pipe 22.

[0093] There is a pressure difference of, for example, 80 to 100 kPa between the atmospheric pressure abatement section 2 and the reduced pressure abatement section 1. This pressure difference causes the treated water to move from the atmospheric pressure abatement section 2 to the reduced pressure abatement section 1. Therefore, the reduced pressure abatement section 1 does not require power such as a circulation pump 8 for circulating the treated water in the water tank 6. The suction port, i.e., the connection between the water reservoir 16a and the circulation piping 22, is located in the atmospheric pressure abatement section 2. Because the outlet scrubber 16 is operated at a temperature sufficiently lower than the boiling point of the treated water, poor circulation due to boiling (or vaporization) of the treated water at the suction port does not occur.

[0094] The treated water that has moved to the reduced pressure abatement section 1 is discharged into the internal space of the inlet scrubber 4 or the internal space of the reaction chamber 5. Because the vapor pressure of the treated water in these spaces is lower than the atmospheric pressure, the treated water vaporizes easily, and the temperature of the discharged treated water drops due to the cooling effect caused by the heat of vaporization and adiabatic expansion. As an example, when water at 40°C was discharged into the space of the reduced pressure abatement section 1 at a pressure of 7 kPa, the temperature of the treated water dropped to 35°C, confirming a temperature drop of 5°C.

[0095] 5, a buffer tank 23 may be provided in communication with the gas inlet 4i to reduce pressure fluctuations of the gas to be treated. The amount of gas to be treated flowing in from a process device upstream of the abatement apparatus 100 may fluctuate due to the influence of the process step. In particular, in the case of ALD (atomic layer deposition) or ALE (atomic layer etching), for example, gas of approximately 100 to 1000 SCCM is turned on and off at 200 ms intervals, resulting in large instantaneous gas flow rate changes and extremely large gas flow rate and pressure fluctuations. Setting the processing capacity of the abatement apparatus 100, for example, the size and number of inlet scrubbers 4, to match the maximum gas flow rate would result in an increase in the size of the abatement apparatus 100, and increased facility and operating costs.

[0096] A buffer tank 23 is connected to a pipe 24 branching from a pipe 10 communicating with the vacuum pump 3 and the gas inlet 4i of the inlet scrubber 4 of the detoxification apparatus 100, thereby absorbing pressure fluctuations associated with changes in the flow rate of the gas to be treated. The buffer tank 23 is located at the most upstream position of the detoxification apparatus 100. When a large flow rate of the gas to be treated instantaneously flows into the pipe 10, the gas to be treated is temporarily stored in the buffer tank 23, thereby suppressing pressure fluctuations. If the conductance of the pipe 24 is G24 and the conductance of the inlet scrubber 4 side of the pipe 10 downstream of the pipe 24 is G10, G10 is preferably set to be smaller than G24 (G10<G24). When multiple inlet scrubbers 4 are provided, the pipe 10 may be branched downstream of the pipe 24, and the branched pipes 10 may be connected to the gas inlet 4i of each inlet scrubber 4.

[0097] A pressure gauge was installed in the inlet scrubber 4 to verify the suppression effect of pressure fluctuations in the buffer tank 23. For the experiment, 100 SLM of gas (nitrogen) was flowed in a configuration without the buffer tank 23. When 20 SLM of gas was added while the pressure in the inlet scrubber 4 was stable at 10 kPa, the pressure rose to 15-20 kPa. On the other hand, a similar experiment was conducted in a configuration with a 7 L buffer tank 23. As a result, it took several tens of seconds (approximately one minute) for a pressure increase in the inlet scrubber 4 to be confirmed. In other words, the pressure increase was delayed by approximately one minute, confirming that pressure fluctuations of several seconds or less could be adequately absorbed. From these experimental results, it can be seen that short-period pressure fluctuations in exhaust gases from ALD processes and the like can be adequately suppressed. It goes without saying that the buffer tank 23 can also be applied to the abatement apparatus 100 of embodiment 1.

[0098] According to the detoxification device of the present invention, after the gas to be treated is detoxified in the reduced pressure detoxification section, the pressure is increased by a pump and the gas is introduced into the atmospheric pressure detoxification section for further detoxification, thereby significantly reducing the amount of nitrogen used for dilution and the energy used for the decomposition reaction of harmful components. Furthermore, the pump that introduces the gas to be treated from the reduced pressure detoxification section to the atmospheric pressure detoxification section has the effect of cooling the treated water used in the reduced pressure detoxification section. Furthermore, the reduced pressure detoxification section and the atmospheric pressure detoxification section are connected by two pumps with different functions and purposes, improving the safety of the device. The detoxification device can be used, for example, as a detoxification device for exhaust gases from film-forming process equipment, and has high industrial applicability.

[0099] 100 Abatement device 1 Reduced pressure abatement section (first abatement section) 2 Atmospheric pressure abatement section (second abatement section) 3 Vacuum pump 4 Inlet scrubber 4a Spray nozzle 4b Gas outlet 4i Gas inlet (first inlet port) 5 Reaction chamber 5a Reactor body 5b Plasma generation means 5c Inlet 5d Flow path 5e Flow path 5f Sprayer (cooling water jet sprayer) 5o Outlet bottom 5s Inner wall surface 5w Water wall 50 Plasma jet torch 51 Torch body 52 Anode 53 Cathode 54 Plasma generation section 55 Supply path (working gas supply port) 55a Piping 55b Flow rate control means 56 Power source 57 Spray outlet 58 Inner cylinder 58a Inner wall 58b Bottom 58c Opening 58d Water storage section 6 Water tank (tank section) 6a Water storage section (reduced pressure water storage section) 6f Upper surface 6s Internal space 6s1 First internal space 6s2 Second internal space 7 Partition wall 8 Circulation pump 9a, 9b, 9c Piping 10 Piping (inlet pipe) 10b Piping 11 Piping 12 Exhaust pump 12i Intake section (intake port) 12o Discharge section (exhaust port) 13 Drain pump 13i Intake section (water intake port) 13o Discharge section (drain port) 14a, 14b Piping 14c Exhaust port (first outflow port) 15 Piping 15a, 15b Piping 15c Water intake port 16 Outlet scrubber 16a Water storage section (atmospheric pressure water storage section) 16b Spray nozzle 16i Gas inlet (second inlet port) 16o Exhaust port (second outlet port) 18 Pipe (water supply pipe) 19 Pipe (exhaust pipe) 20 Pipe (bypass pipe) 21 Pipe (water supply pipe) 22 Circulation pipe 22a, 22b, 22c Circulation pipe (branch pipe) 22i Water intake end 22o Drain end 23 Buffer tank 24 Pipe 25 Chamber 27 Inlet port 28 Exhaust port 29 Pipe V1, V2, V3, V4, V5, V6, V7, V27, V28 Valve (on / off valve) CV1, CV2, CV3, CV4 Check valve RS Reaction space P Plasma jet CM Concentration meter PG Pressure gauge

Claims

1. A detoxification device for detoxifying a gas to be treated, comprising a reduced pressure detoxification section, an atmospheric pressure detoxification section, and an exhaust pump, wherein the reduced pressure detoxification section has a first inlet port and a first outlet port, the atmospheric pressure detoxification section has a second inlet port and a second outlet port, the first outlet port communicates with an intake port of the exhaust pump, the second inlet port is connected to an exhaust port of the exhaust pump, and the exhaust pump pressurizes the gas to be treated.

2. The abatement device according to claim 1, characterized in that the reduced pressure abatement section has an inlet scrubber, a reaction chamber and a water tank, the atmospheric pressure abatement section has an outlet scrubber, the water tank is connected to the inlet scrubber, the outlet of the inlet scrubber is connected to the inlet of the reaction chamber, the water tank stores treated water to be supplied to the inlet scrubber, and the first outlet port is provided in the water tank.

3. The abatement system according to claim 2, further comprising a drainage pump, the water tank communicating with a suction port of the drainage pump, and the outlet scrubber connected to the drainage port of the drainage pump.

4. The abatement system according to claim 3, further comprising a circulation pipe, the circulation pipe connecting the outlet scrubber with the inlet scrubber, the reaction chamber and the water tank.

5. The abatement device according to claim 1, further comprising a buffer tank, said buffer tank communicating with said first inlet port.

6. The abatement device according to claim 2, characterized in that the reaction chamber has a reactor body and a plasma generating means, and the inner wall surface of the reactor body is provided with a plurality of cooling water ejectors arranged in the circumferential direction.

7. A detoxification device as claimed in any one of claims 1 to 6, characterized in that it is provided with a pipe connecting the reduced pressure detoxification section and the atmospheric pressure detoxification section, and an opening / closing valve and a check valve are provided in series in the pipe, and the check valve is arranged downstream of the opening / closing valve.

8. A method for detoxification comprising: a decompression detoxification step for detoxifying a gas to be treated discharged from a gas generation source under reduced pressure; a pressurization step for pressurizing the gas to be treated to atmospheric pressure; an atmospheric pressure detoxification step for detoxifying the gas to be treated under atmospheric pressure; and a discharge step for discharging the gas to be treated.

9. The decontamination method according to claim 8, characterized in that the reduced pressure decontamination step includes a reduced pressure water spraying treatment step of spraying water onto the gas to be treated, and a heat treatment step of subjecting the gas to heat treatment using plasma, and the atmospheric pressure decontamination step includes an atmospheric pressure water spraying treatment step of spraying water onto the gas to be treated.

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