Gas disinfestation device and gas treatment method

Abstract

The invention provides a gas disinfection device and a gas processing method, which can realize energy conservation and expand the range of use conditions. This gas disinfestation device is provided with a first reactor 4 and a second reactor 5. The first reactor 4 has a first reaction space 6 surrounded by a heating wall 7, and the second reactor 5 has a second reaction space 16 surrounding the heating wall 7. A gas and a reducing agent are introduced from one end side of the first reaction space 6, and the other end side of the first reaction space 6 communicates with the second reaction space 16. Oxygen or an oxygen-containing gas is introduced into the second reaction space (16).

Description

Technical Field

[0001] The invention relates to a gas harm removal device and a gas harm removal method. Background Art

[0002] Sometimes, exhaust gas generated in various industrial processes such as manufacturing contains components that may have adverse effects on the human body. For example, in semiconductor manufacturing plants, N2O is sometimes used as an oxidant in film formation processes. In addition, thermal NOx is sometimes generated by high-temperature processes such as the combustion of nitrogen compounds. In particular, N2O is a greenhouse gas with a high global warming coefficient, and its emission needs to be reduced. As one of the exhaust gas detoxification devices, there is known a device that thermally decomposes such harmful components. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent No. 7021730 Patent Document 2: Japanese Patent Application Publication No. 2005-125285 Patent Document 3: Japanese Patent Application No. 2008 / 096466 Patent Document 4: Japanese Patent Application Laid-Open No. 2008-253903 Summary of the invention Problems to be solved by the invention

[0004] For example, in order to thermally decompose nitrous oxide (N2O) which is a nitrogen oxide, it is necessary to perform heat treatment at a high temperature. Therefore, a detoxification device using thermal decomposition generally requires high power, and energy saving of the detoxification device is required. Among the existing pest control devices, there are also pest control devices that can achieve energy saving. However, according to various requirements of users of the pest control devices (such as further low temperature, etc.), it is required to further expand the range of use conditions of the pest control devices.

[0005] In view of the above problems, an object of the present invention is to provide a gas detoxification device and a gas detoxification method that can achieve energy saving and expand the range of use conditions to expand the range of choices for users. Technical means to solve problems

[0006] The gas detoxification device (1) according to the present invention is characterized in that: It has a first reactor (4) and a second reactor (5), The first reactor (4) has a first reaction space (6) surrounded by a heated wall (7), The second reactor (5) has a second reaction space (16) surrounding the heating wall (7), The gas and the reducing agent are introduced from one end of the first reaction space (6), The other end side of the first reaction space (6) is connected to the second reaction space (16). Oxygen or an oxygen-containing gas is introduced into the second reaction space (16).

[0007] By forming the gas harm removal device of this structure, the range of usable conditions that can meet the requirements of users can be expanded by selecting the reducing agent. In addition, the reducing agent can be reacted with oxygen in the second reaction space, and its combustion heat can be used for the reduction reaction in the first reaction space, which can contribute to energy saving.

[0008] Furthermore, in the gas detoxification device (1) according to the present invention, in addition to the above-mentioned structure, the first reactor (4) may include a gas flow regulator (13) in the first reaction space (6).

[0009] By forming the gas detoxification device with such a structure, the reduction reaction of the gas in the first reaction space can be promoted, which can contribute to the improvement of the detoxification efficiency.

[0010] In addition, the gas detoxification device (1) according to the present invention may be, based on the above structure, The heating wall (7) has a straight tube shape, The gas flow regulator (13) has a gas flow control unit (15). The length direction of the airflow control portion (15) is arranged to be parallel to the length direction of the heating wall (7).

[0011] With the gas detoxification device having such a structure, the reduction reaction in the first reaction space can be promoted by the gas flow control unit, and the gas flow regulator can be easily attached to and detached from the first reactor, thereby improving the maintainability.

[0012] Furthermore, in the gas detoxification device (1) according to the present invention, in addition to the above-mentioned structure, the reducing agent may be a combustible gas.

[0013] By forming the gas harm removal device of this structure, as a reducing agent, a flammable reducing gas can be appropriately selected and burned in the second reactor, and its heat energy can be used for the reduction reaction in the first reactor. In addition, by selecting hydrogen as the reducing agent in particular, the low temperature of the treatment temperature can be achieved, and the use temperature range of the harm removal treatment can also be expanded, thereby expanding the scope of the user's selection.

[0014] Furthermore, in the gas detoxification device (1) according to the present invention, in addition to the above-mentioned configuration, the reducing agent may be an organic solvent.

[0015] By forming the gas detoxification device of such a structure, it is also possible to meet the requirements of users who do not want to use flammable gas.

[0016] In addition, the gas detoxification system (100) according to the present invention is characterized in that: The gas detoxification device (1), an inlet scrubber (2) and an outlet scrubber (3) are provided. The inlet scrubber (2) is in communication with the first reactor (4), The outlet scrubber (3) is in communication with the second reactor (5).

[0017] By forming a gas detoxification system of this structure, dust, water-soluble components, etc. can be removed in the inlet scrubber, and then the detoxification target components in the gas can be decomposed in the gas detoxification device, cooled and appropriately diluted in the outlet scrubber and released into the atmosphere.

[0018] In addition, the method for removing harm from gas according to the present invention is characterized in that it comprises: a gas introduction step of introducing the gas into the first reactor (4); A reduction step of mixing the reducing agent introduced into the first reactor (4) with the gas and reducing the gas; a combustion step of introducing the gas after the reduction step and the remaining reducing agent into the second reactor (5) and reacting the oxygen introduced into the second reactor (5) with the remaining reducing agent; and A degassing step is performed to discharge the gas after the combustion step from the second reactor (5).

[0019] By forming such a method for removing harm from gas, the range of usable conditions that can meet the requirements of users can be expanded by selecting a reducing agent. In addition, the reducing agent can react with oxygen in the second reaction space, and its combustion heat can be used for the reduction reaction in the first reaction space, which can contribute to energy saving. Effects of the Invention

[0020] According to the present invention, it is possible to provide a gas detoxification device and a gas detoxification method that can achieve energy saving and expand the range of use conditions to expand the range of choices for users. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a cross-sectional view schematically showing the main structure of a gas detoxification system 100 using the gas detoxification device 1. (Embodiment 1) Figure 2 (A) is a partial side view showing the structure of the gas flow adjuster 13 installed on the heating wall 7. Figure 2 (B) is a top view showing the arrangement relationship between the heating wall 7 and the support portion 14 of the gas flow adjuster 13, Figure 2 (C) is a bottom view showing the arrangement relationship between the heating wall 7 and the pipe 9 for supplying the reducing gas. Figure 3 (A) is a graph showing the relationship between the N2O removal efficiency and the hydrogen flow rate. Figure 3 (B) is a graph showing the relationship between the cost required for exhaust gas treatment and the treatment temperature. Figure 4 Schematic diagram showing the main structure of the gas detoxification system 100. (Embodiment 2) Figure 5 (A) is a graph showing the relationship between the removal efficiency of N2O and the supply amount of IPA. Figure 5 (B) is a graph showing the relationship between the N2O removal efficiency and the ethanol supply amount. Figure 6 (A) is a graph showing the dependence of NF3 removal efficiency on hydrogen flow rate, Figure 6 (B) is a graph showing the dependence of the NF3 removal efficiency on the ethanol flow rate. Figure 6 (C) is a graph showing the dependence of the NF3 removal efficiency on the isopropyl alcohol (IPA) flow rate. DETAILED DESCRIPTION

[0022] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. However, the following embodiments do not constitute a restrictive interpretation of the main idea of ​​the present invention. In addition, sometimes the same or the same type of components are marked with the same figure number and the description is omitted.

[0023] Furthermore, terms such as "parallel", "orthogonal", "same", lengths, angle values, etc. used in this specification to determine shapes, geometric conditions and their degrees are not limited to the strict meanings, but are interpreted to include the scope of the degree to which the same function can be expected.

[0024] (Implementation Method 1) Hereinafter, a gas detoxification system 100 according to an embodiment of the present invention will be described. Figure 1 1 is a cross-sectional view showing the main structure of a gas detoxification system 100 using the gas detoxification device 1. Figure 1 In the figure, arrows schematically show the flow of gas (for the sake of understanding). Figure 2 (A) is a schematic diagram showing the gas flow around the gas flow regulator 13. Figure 2(B) shows the arrangement relationship between the heating wall 7 and the support portion 14 of the gas flow regulator 13 in the inner tube heater type detoxification device, and is a top view observed from the upper part of the heating wall 7. Figure 2 (C) shows the arrangement relationship between the heating wall 7 and the pipe 9 for supplying the reducing gas, and is a bottom view of the heating wall 7 as seen from the bottom surface side.

[0025] The gas detoxification system 100 includes a gas detoxification device 1, an inlet scrubber 2, and an outlet scrubber 3. The gas detoxification device 1 performs detoxification treatment on a to-be-treated gas containing nitrogen oxides (N2O, etc.). exist Figure 1 In the embodiment, the gas detoxification device 1, the inlet scrubber 2 and the outlet scrubber 3 are integrally formed, but they may be independently formed and connected by pipes. When the inlet scrubber 2 and the outlet scrubber 3 are independently formed, known wet scrubbers may be used respectively.

[0026] The gas detoxification device 1 includes a first reactor and a second reactor, that is, an internal reactor (internal reactor) 4 and an external reactor (external reactor) 5 . The internal reactor 4 has an internal reaction space 6 (first reaction space), and the internal reaction space 6 is surrounded by the inner wall surface of a cylindrical heating wall 7 (reaction wall) opened at both ends.

[0027] The heating wall 7 can be maintained at a predetermined temperature. For example, the heating wall 7 includes a heating mechanism (for example, a heating wire) and can be maintained at a desired temperature, for example (not limited to) 700°C to 1000°C. The temperature control method may utilize a known technique using a thermometer for detecting the temperature of the heating wall 7 and a control device, such as PID control.

[0028] The surface (inner wall surface and outer wall surface) of the heating wall 7 covers the above-mentioned heating mechanism and is made of a known fire-resistant and corrosion-resistant material, and is resistant to the chemical reaction in the gas detoxification device 1 . The internal reactor 4 is configured such that the internal reaction space 6 is maintained at a high temperature by the heating wall 7 , and in this respect, it can be considered as a substantially hot wall type reactor.

[0029] A reducing gas such as hydrogen, methane or other hydrocarbon gas is supplied as a reducing agent (reducing substance) from one end of the internal reaction space 6 (or the heating wall 7) through a reducing gas supply port 8 (hereinafter referred to as a gas supply port 8). A pipe 9 (reducing gas supply line) for supplying a reducing gas is connected to the gas supply port 8 , and the reducing gas is fed from a supply source such as a bottle (not shown) to the gas supply port 8 through the pipe 9 . In addition, the reducing gas is not limited to the above-mentioned example, and a combustible gas that decomposes nitrogen oxides into nitrogen and water and reacts with oxygen may be used.

[0030] It is generally known that in order to thermally decompose nitrogen oxides, such as N2O, it is necessary to heat to 1100°C or more, but by adding methane, decomposition can be performed at 900°C, and low temperature gas treatment can be achieved. As described later, by using hydrogen as an added gas, further low temperature can be achieved, for example, N2O can be decomposed at 800°C. From the viewpoint of reducing power consumption, hydrogen can be appropriately used as a reducing gas. Therefore, the temperature range that can be used for the harm removal treatment can be expanded (the low temperature region can be expanded), and thus the temperature selection range of the user of the harm removal device can be expanded. When hydrogen is used as the reducing gas, for example, a hydrogen supply line is usually provided in a semiconductor factory, so the existing supply line can be used. The reducing gas to be used can also be appropriately selected according to the equipment owned by the user.

[0031] The reducing gas supplied from the supply source is controlled in flow rate by a flow control device FCD such as a mass flow controller, transported through the pipe 9, and introduced into the internal reaction space 6 through the gas supply port 8. (See Figure 2 (C.)

[0032] The gas detoxification device 1 is provided with a gas inlet 10 (processed gas inlet) for introducing a processed gas into the internal reaction space 6. The gas inlet 10 is located at one end side of the internal reaction space 6 (more specifically, the heating wall 7). exist Figure 1 In the example shown, the gas supply port 8 is provided on the wall surface of the introduction pipe 50 connected to one end (bottom surface) of the heating wall 7, and the reducing gas is supplied to the internal reaction space 6 from below the one end of the heating wall 7 through the gas introduction port 10. In this case, the reducing gas is introduced into the internal reaction space 6 after being mixed with the treated gas. In addition, the gas supply port 8 can also be provided on the wall surface at one end side of the heating wall 7, and the reducing gas is supplied from above the gas inlet port 10. In order to introduce the reducing gas into the internal reaction space 6 and make it fully react with the treated gas, the gas supply port 8 only needs to be located at one end side of the internal reaction space 6, and thus, the introduction pipe 50 can be located at one end (bottom surface) of the heating wall 7, and can also be located at the wall surface at one end side of the heating wall 7.

[0033] The treated gas may be directly introduced into the internal reactor 4 of the gas detoxification device 1 from the gas inlet 10, or may be supplied to the gas inlet 10 via the inlet scrubber 2. The inlet scrubber 2 connected to the internal reactor 4 may use a known device. exist Figure 1 In the example shown, the inlet washer 2 has a straight-tube type inlet washer body 21 and a nozzle 22 for discharging liquid. The treated gas introduced from the gas inlet 23 to the inlet scrubber main body 21 (at Figure 1 In order to remove dust, water-soluble components, etc., a liquid medicine such as water is released (sprayed in a mist form) from the nozzle 22. The released liquid medicine is recovered in the liquid medicine tank 40. The recovered liquid medicine is sent to the nozzle 22 by the pump P through the circulation pipe 24. Furthermore, the chemical tank 40 is provided with a drain valve 41 , and the chemical can be discharged from the drain valve 41 for replacement of the chemical during periodic maintenance or the like.

[0034] The treated gas subjected to dust removal and other treatments in the inlet scrubber 2 flows out from the gas outlet 26 provided in the inlet scrubber body 21 and flows into the internal reactor 4 of the gas detoxification device 1 through the gas inlet 10 . exist Figure 1 In the example shown, the space between the liquid level of the liquid tank 40 and the ceiling surface of the liquid tank 40 is used as a flow path (inflow path FPi) from the inlet scrubber 2 to the gas detoxification device 1 (internal reactor 4). In addition, a pipe for gas circulation may be separately provided to connect the gas outlet 26 with the gas inlet 10.

[0035] like Figure 1 , Figure 2 As shown in FIG. 1B , a gas outlet 12 opened to the external reaction space 16 is provided at the other end of the internal reactor 4 opposite to the gas inlet 10 . The other end side of the internal reaction space 6 communicates with the external reaction space 16 . Therefore, the treated gas introduced from the gas inlet 10 moves along the longitudinal direction of the internal reaction space 6 (or the heating wall 7 ) together with the reducing gas introduced from the gas supply port 8 , and flows out from the gas outlet 12 to the external reaction space 16 .

[0036] A gas flow regulator 13 is provided in the internal reaction space 6 of the internal reactor 4 of the gas detoxification device 1. Figure 2 As shown in (C), the reducing gas introduced from the gas supply port 8 is released toward the gas flow regulator 13. Alternatively, the reducing gas may be released from the gas supply port 8 so as to flow along the inner wall surface of the heating wall 7.

[0037] Figure 2 (A) is a partial cross-sectional view showing the structure of the gas flow regulator 13 installed on the heating wall 7, and schematically shows the gas flow around the gas flow regulator 13. like Figure 2 As shown in FIG. 2 (A), the gas flow adjuster 13 includes a T-shaped support portion 14 and a gas flow control portion 15 .

[0038] The support portion 14 has a head portion 14 a and a shaft portion 14 b . The head 14a is provided at the gas outlet 12 of the heating wall 7 so as to be in contact with the surface of the upper end of the heating wall 7. (See Figure 2 (A) Figure 2 (B) By configuring the heating wall 7 to have a straight tube shape and configuring the shaft portion 14 b to have a straight rod shape, the shaft portion 14 b can be easily inserted into the heating wall 7 . The length of the head 14a in the longitudinal direction is longer than the inner diameter of the heating wall 7, and the shaft 14b of the support 14 is suspended in the internal reaction space 6 through the head 14a. The shaft 14b is arranged parallel to the longitudinal direction of the internal reaction space 6 from the gas outlet 12 toward the gas inlet 10. By forming such a structure, it becomes easy to assemble and disassemble the gas flow conditioner 13 to the heating wall 7. For example, the gas flow conditioner 13 removed from the internal reactor 4 can be easily reattached after cleaning, and the maintainability can be improved.

[0039] The airflow control unit 15 is fixed to the shaft portion 14 b . In the example shown in the figure, the components of the airflow control unit 15 are arranged in a direction parallel to the longitudinal direction of the heating wall 7 . The reducing gas flowing from the gas supply port 8 through the pipe 9 flows toward the gas flow control unit 15 and mixes with the gas to be processed to form a mixed gas. As described later, the mixed gas of the gas to be processed and the reducing gas is stirred by the gas flow control unit 15.

[0040] A mixed gas formed by mixing the gas to be processed and the reducing gas flows from the gas inlet 10 toward the gas outlet 12 in the internal reaction space 6 . The gas flow control unit 15 of the gas flow regulator 13 provided in the internal reaction space 6 partially blocks the linear flow (or laminar flow) of the mixed gas from the gas inlet 10 to the gas outlet 12 . For example, Figure 2 As shown in (A) of FIG. 1 , the flow of the mixed gas is partially blocked by the airflow control unit 15 , and a complex flow (turbulent flow) is generated under the influence of vortices, for example, as shown by arrows in the figure. Therefore, the mixed gas stays in the internal reaction space 6 for a longer time, and the mixing of the decomposition target component of the treated gas and the reducing gas is further promoted, and the decomposition reaction of the decomposition target component is promoted. As a result, the decomposition temperature of the nitrogen oxides in the internal reaction space 6 can be lowered. Alternatively, the gas flow regulator 13 can contribute to shortening the length of the inner reaction space 6 (heating wall 7) in the longitudinal direction required for the reduction reaction. The gas flow regulator 13 can contribute to energy saving and miniaturization of the gas detoxification device 1.

[0041] The gas flow adjuster 13 , in particular, the gas flow control unit 15 , may be in various shapes as long as it is partially configured to at least partially block the laminar flow of the mixed gas in the internal reaction space 6 .

[0042] When hydrogen is used as an example of the reducing gas, in the internal reactor 4, nitrogen oxides and hydrogen are converted into nitrogen and water by, for example, the following reaction. N2O+H2→N2+H2O(+NO+NO2) 2NO+2H2→N2+2H2O 2NO2+4H2→N2+4H2O Furthermore, when hydrocarbons such as methane are used as the reducing gas, carbon dioxide is further generated.

[0043] The gas reduced in the internal reactor 4 flows through the gas outlet 12 to the external reactor 5 accommodating the internal reactor 4. The introduced reducing gas is consumed by the reduction reaction, but the remaining reducing gas that does not participate in the reduction of nitrogen oxides remains. The reducing gas (for example, hydrogen or hydrocarbon) is a combustible gas, and therefore, as described below, the remaining excess reducing gas is combusted in the external reactor 5 .

[0044] The external reactor 5 has an external reaction space 16 (second reaction space), and the external reaction space 16 is surrounded by a heat insulating wall 17. The external reaction space 16 is formed as an outer wall surface of the heating wall 7 surrounding the internal reactor 4. Unlike the internal reactor 4 , the external reactor 5 is configured to be supplied with heat energy from a heating wall 7 provided inside the external reactor 5 .

[0045] Oxygen or oxygen-containing gas (eg, air) is supplied to the external reaction space 16 via a pipe 19 provided at an air intake port 18. For example, oxygen can be supplied by introducing dry air (indicated by DA in the figure) using a blower (not shown). The reducing gas (hydrogen) contained in the gas flowing into the external reaction space 16 from the gas outlet 12 is a combustible gas, and reacts (burns) with oxygen by the heat energy supplied from the heating wall 7 to be converted into water. 2H2+O2→2H2O When hydrocarbons are used as the reducing gas, they are converted into water and carbon dioxide.

[0046] The combustion heat of hydrogen in the external reaction space 16 is used to heat the heating wall 7 of the internal reactor 4. Therefore, the energy (electricity) required for the heating mechanism for heating the heating wall 7 can be reduced, which contributes to energy saving.

[0047] The gas purified in the external reactor 5 is discharged to the outside of the external reactor 5 through the gas discharge port 11 (purified gas discharge port). Furthermore, the high-temperature gas discharged from the gas discharge port 11 may be used to heat the gas to be processed introduced from the gas inlet 10 into the internal reactor 4 . For this purpose, a heat exchanger (not shown) may be provided between the inlet pipe 50 connected to the gas inlet port 10 and the exhaust pipe 51 connected to the gas exhaust port 11. The exhausted heat energy can be effectively utilized, thereby achieving energy saving of the gas detoxification device 1.

[0048] Especially in Figure 1 In the example shown, the treated gas is introduced into the internal reaction space 6 from the gas inlet 10 located at one end (first end) of the heating wall 7, and then the gas flows into the external reaction space 16 from the other end (second end) of the heating wall 7 and flows along the length direction of the heating wall 7. Thereafter, the gas is discharged from the gas outlet 11 of the external reactor 5 located at the first end. Therefore, the gas inlet 10 and the gas outlet 11 are located on the first end side of the heating wall 7 and are close to each other, so that heat exchange between the gas inlet 10 and the gas outlet 11 becomes easy.

[0049] The gas after reduction and oxidation (combustion) treatment by the gas detoxification device 1 is introduced into the outlet scrubber 3 through the inlet 30. Figure 1 In the example shown, the space between the chemical liquid surface of the chemical liquid tank 40 and the ceiling surface of the chemical liquid tank 40 is used as a flow path (outflow path FPo) from the gas detoxification device 1 (external reactor 5) to the outlet scrubber 3.

[0050] exist Figure 1In the example shown, the inlet scrubber 2 and the outlet scrubber 3 share a chemical tank 40. Therefore, the outflow path FPo and the inflow path FPi are separated by the partition wall 42. As a result, the gas before being treated by the gas detoxification device 1 is prevented from mixing with the gas after being treated. Furthermore, a gas circulation pipe may be separately provided to communicate between the gas exhaust port 11 and the inlet 30 of the outlet scrubber 3 . In addition, the inlet scrubber 2 and the outlet scrubber 3 may be provided separately without sharing the chemical solution tank 40 .

[0051] like Figure 1 As shown, the outlet scrubber 3 communicating with the external reactor 5 has a straight-tube type outlet scrubber body 31 and a nozzle 32 for discharging liquid. The gas introduced from the inlet 30 to the outlet scrubber body 31 is cooled by a chemical liquid such as water discharged from the nozzle 32, and dust, water-soluble components, etc. are removed. The released chemical solution is recovered in the chemical solution tank 40 . Figure 1 Although an example is shown in which new chemical liquid (water or the like) is supplied from a supply source (not shown), the chemical liquid recovered in the chemical liquid tank 40 may be circulated by a pump similarly to the inlet scrubber 2 .

[0052] The outlet scrubber body 31 may include a dilution port 33 above the nozzle 32 as a flow path for taking in dry air for dilution (indicated by DA in the figure).

[0053] An exhaust fan 34 is provided at the top outlet of the outlet scrubber body 31 , and the exhaust fan 34 can discharge the treated exhaust gas into the atmosphere.

[0054] Thus, the gas detoxification device 1 has two reactors with different functions, namely, an internal reactor 4 for reduction reaction and an external reactor 5 for oxidation reaction, wherein the internal reactor 4 is arranged inside the external reactor 5. The heating wall 7 of the internal reactor 4 surrounds the internal reaction space 6 and heats the internal reaction space 6. The external reaction space 16 is configured to surround the heating wall 7. That is, the external reaction space 16 accommodates the heating wall 7, is heated by the heating wall 7, and heats the heating wall 7 by utilizing the heat generated by the oxidation reaction in the external reaction space 16. As a result, the energy consumption required for heating the heating wall 7 can be reduced. Thus, the external reaction space 16 can effectively utilize the reducing gas required for the reduction reaction of the internal reactor 4. In addition, there is no need to separately provide a reducing gas processing device, and the area occupied by the gas detoxification device 1 can be reduced.

[0055] Figure 3 (A) is a graph showing the relationship between the N2O removal efficiency and the flow rate of hydrogen introduced into the internal reactor 4 at a treatment temperature of 700°C to 850°C in the internal reactor 4. The vertical axis is the N2O removal efficiency (%), and the horizontal axis is the hydrogen flow rate (SLM). Figure 3 In (A), □ (hollow squares) represent data at 700°C, ▲ (solid triangles) represent data at 750°C, ◆ (solid diamonds) represent data at 800°C, and △ (hollow triangles) represent data at 850°C. In addition, the removal efficiency was verified under the condition of N2O flow rate of 7 (SLM). Figure 3 (B) is a graph showing the relationship between the cost and the treatment temperature required for the exhaust gas treatment in the gas detoxification device 1. The vertical axis is the calculated value of the cost (arbitrary unit), and the horizontal axis is the treatment temperature (°C).

[0056] like Figure 3 As shown in (A), as the hydrogen flow rate increases, the removal efficiency of N2O increases. In addition, with the lowering of the treatment temperature, the removal efficiency of N2O tends to decrease, but by increasing the hydrogen flow rate, the removal efficiency of N2O can be improved. When the treatment temperature is 850°C to 750°C, a higher N2O removal efficiency can be obtained. In addition, even if the treatment temperature is lowered to 700°C, a higher N2O removal efficiency can be obtained by further increasing the hydrogen flow rate. However, when the treatment temperature is 700°C, the required amount of hydrogen tends to increase significantly. In addition, in the above verification, although a large amount of N2O was processed, it was confirmed that NO x The concentration is still suppressed to about 200 ppm. In addition, it is also possible to further dilute the air supplied from the dilution port 33 to a discharge standard (for example, less than 100 ppm to 150 ppm) that meets the discharge criteria of the target facility as needed. Generally, if only N2O is thermally decomposed, several thousand ppm of NO will be produced. x Therefore, it is difficult to inhibit NO x However, as described above, it can be understood that the NO from the gas detoxification device 1 x The concentration of N2O is suppressed to below about 200 ppm, which is a very low concentration. That is, the gas detoxification device 1 can take into account both the high N2O removal efficiency and the NO x In addition, it can be further understood that the gas detoxification device 1 is an excellent detoxification device that can also achieve low temperatures for the treatment temperature and can take both of the above into account in a wide range of temperature regions. Furthermore, since the remaining reducing gas, ie, the combustible gas (hydrogen) is consumed by combustion, the emission standard can be satisfied.

[0057] Figure 3 (B) shows the relationship between cost (calculated value) and processing temperature. Figure 3 As shown in (B), the cost is minimized when the processing temperature is 800°C. If the treatment temperature is lowered, the amount of hydrogen required increases, so the cost of hydrogen gas increases. In particular, the cost of hydrogen gas tends to increase significantly at 700°C. On the other hand, if the treatment temperature is increased, the energy (electricity) required for heating increases. Figure 3 From the perspective of cost shown in (B), 800°C is optimal. Thus, the gas detoxification device 1 can realize the low temperature of the processing temperature and the range of the temperature that can be adopted becomes wider, thereby expanding the selection range of the components considering the heat resistance. By low temperature, the cooling time during maintenance is shortened and the maintainability is also improved. Furthermore, if one wishes to reduce the amount of hydrogen used, a higher treatment temperature may be selected. The optimum treatment temperature can be adopted by comprehensively considering the concentration of nitrogen oxides in the gas of the object of the detoxification treatment, the maintainability, operation and management of the gas detoxification device 1, the heat resistance and durability of the components used, etc. In this way, the range of the use conditions of the gas detoxification device 1 that can cope with the user's requirements is expanded.

[0058] (Method for removing harm from the treated gas) The method for removing nitrogen oxides (N2O) using the gas removal system 100 including the gas removal device 1 having the above-described structure includes the following steps. Step 0: The heating wall 7 as the heating means is controlled to set the temperature of the internal reaction space 6 to a predetermined temperature, for example, 800° C. At this time, the external reaction space 16 is also heated and maintained at a predetermined temperature. In addition, step 0 is one of the start-up steps of the gas detoxification device 1 . Step 1: The treated gas (exhaust gas) is introduced into the inlet scrubber 2 to remove dust, water-soluble components, etc. contained in the treated gas. Step 2: Introduce the gas to be processed into the internal reactor 4. Step 3: The reducing agent introduced into the internal reactor 4 is mixed with the treated gas in the internal reactor 4 (internal reaction space 6) (forming a mixed gas), and the treated gas is reduced by the reducing agent (reducing gas). In addition, reducing the treated gas more specifically means reducing the detoxification target component (in this case, nitrogen oxides) in the treated gas. Step 4: The mixed gas treated in the internal reactor 4 (the exhaust gas after the reduction treatment and the remaining reducing agent) is released to the external reactor 5 . Step 5: The oxygen (air) introduced into the external reactor 5 (external reaction space 16) is reacted with the remaining reducing agent contained in the treated mixed gas flowing out of the internal reactor 4 (internal reaction space 6), that is, the reducing agent not consumed by the reduction reaction of the nitrogen oxides, to burn the remaining reducing agent. The heating wall 7 is heated by the combustion heat. Step 6: The gas (mixed gas) treated in the external reactor 5 is released (towards the outlet scrubber 3). Step 7: In the outlet scrubber 3, the gas treated in the external reactor 5 is cooled as required. Step 8: Release the gas treated in the outlet scrubber 3 into the atmosphere. In addition, in the above steps, the processing steps of the gas to be processed in the gas detoxification device 1 are steps 2 to 6.

[0059] Furthermore, in step 3, the gas flow regulator 13 provided in the internal reactor 4 has the effect of promoting the mixing of the exhaust gas and the reducing agent and prolonging the residence time of the mixed gas in the internal reaction space 6, thereby promoting the reduction reaction.

[0060] (Implementation Method 2) Hereinafter, an embodiment of the gas detoxification device 1 which does not use a reducing gas (hydrogen or the like) as a reducing agent will be described. Figure 4 Schematic diagram showing the main structure of the gas detoxification system 100. Figure 1 The difference between them is that there is no pipe 9 for supplying the reducing gas to the gas detoxification device 1, and instead there is a supply line for an organic solvent (for example, alcohol such as isopropyl alcohol IPA). The differences from the first embodiment will be described in detail below.

[0061] The flammable organic solvent is supplied to the internal reactor 4 through the discharge portion 90 provided in the gas inlet port 10. Since the liquid organic solvent is used as the reducing agent (reducing substance), a two-fluid nozzle can be appropriately used as the discharge portion 90, for example. A pipe 91 (organic solvent supply line) for supplying an organic solvent and a pipe 92 (carrier gas supply line) for supplying a carrier gas such as nitrogen or argon for the organic solvent are connected to the discharge portion 90 . Furthermore, the organic solvent serving as the reducing agent is flammable.

[0062] The organic solvent is delivered from an organic solvent container (tank) 93 to the discharge portion 90 via a pipe 91 by a pump (not shown). A flow controller 94 is provided in the pipe 91 to control the flow rate of the organic solvent to a predetermined flow rate.

[0063] The carrier gas is delivered from a bottle 95 (gas container) to the discharge unit 90 via a pipe 92. A flow controller 96 is provided in the pipe 92 to control the flow rate of the carrier gas to a predetermined flow rate.

[0064] The organic solvent supplied to the discharge portion 90 is discharged into the internal reaction space 6 through the gas introduction port 10 together with the carrier gas. A two-fluid nozzle can be appropriately used as the discharge portion 90. The organic solvent supplied to the two-fluid nozzle as the discharge portion 90 is mixed with the carrier gas and transported to the internal reaction space 6 of the internal reactor 4 by the carrier gas. Alternatively, the organic solvent and the carrier gas may be mixed, the mixed gas may be transported to the discharge portion 90 through a single pipe, and discharged from the discharge portion 90 into the internal reaction space 6. However, the use of a two-fluid nozzle makes it easier to control the organic solvent concentration of the mixed gas. The means for supplying the organic solvent to the internal reactor 4 is not limited to the above, and any means may be used as long as the supply amount of the organic solvent can be controlled and introduced into the internal reaction space 6 .

[0065] As the organic solvent, IPA, which is used for various purposes such as cleaning and drying at manufacturing sites, can be used as a non-limiting example. In addition, as the carrier gas, inexpensive nitrogen can be appropriately used as an inert gas, but the invention is not limited thereto.

[0066] In the internal reactor 4 , the nitrogen oxides mixed with the organic solvent are converted into nitrogen and water by, for example, the following reaction. If the chemical formula of the organic solvent is C x H y O z , then the reaction equation is as follows. N2O+C x H y O z →N2+H2O+CO2 NO+C x H y O z →N2+H2O+CO2 NO2+C x H y O z →N2+H2O+CO2 Furthermore, the coefficients of the reaction equations are omitted. For example, when the organic solvent is IPA (C3H8O), the reaction formula with N2O is as follows. 9N2O+C3H8O→9N2+4H2O+3CO2

[0067] Figure 5 (A) is a graph showing the dependence of the removal efficiency of N2O on the supply amount of IPA. Figure 5 (B) is a graph showing the dependence of the removal efficiency of N2O on the supply amount of anhydrous ethanol. Figure 5 In (A), the vertical axis is the removal efficiency of N2O, and the horizontal axis is the flow rate of IPA. Figure 5 In (B), the vertical axis is the removal efficiency of N2O, and the horizontal axis is the flow rate of ethanol. In addition, the flow rate of N2O was set to 7 (SLM) and the experiment was conducted. In addition, Figure 5 In (A), ◆ (solid diamond) is the data verified at a processing temperature of 850°C. Figure 5 In (B), □ (hollow squares) and ◆ (solid diamonds) represent data verified at processing temperatures of 800° C. and 850° C., respectively, but the processing temperature is not limited to these temperatures. like Figure 5 As shown in (A), it can be understood that as the flow rate of IPA increases, the removal efficiency increases, and a high removal efficiency of more than 90% can be achieved. In addition, if Figure 5 As shown in (B), it can be understood that, like IPA, as the flow rate of ethanol increases, the removal efficiency increases, and a high removal efficiency of more than 90% can be achieved. If the removal efficiencies at treatment temperatures of 800°C and 850°C are compared, although the removal efficiency at 850°C tends to show a higher value, there is actually no large difference, and the temperature dependence is small.

[0068] From the above, it can be understood that when an organic solvent is used as a reducing agent, a high removal efficiency of N2O can be achieved, and the processing temperature can be lowered to about 800°C. In addition, it was confirmed that, regardless of the treatment conditions, although a large amount of N2O was treated, the NO discharged from the gas detoxification device 1 was x The concentration of N2O is still suppressed to a lower concentration below about 200ppm, which can also take into account the higher N2O removal efficiency and NO x reduction in production. Therefore, it can be understood that in the gas detoxification device 1 using an organic solvent as a reducing agent, both the detoxification efficiency of N2O and the efficiency of NO x The generation of is reduced, and in addition, an excellent harm removal device can be achieved at a low temperature of about 800°C.

[0069] In addition, similarly to the first embodiment, the remaining reducing agent, namely the organic solvent, can be burned by the external reactor 5, and the heat energy generated by the combustion can be used as energy required for the reduction reaction in the internal reactor 4, which contributes to reducing energy consumption.

[0070] In this way, an organic solvent can be used as a reducing agent, and the gas detoxification device 1 of this embodiment can be used when it is not desired to use a combustible gas such as hydrogen. The gas detoxification device 1 of the first embodiment and the gas detoxification device 1 of the second embodiment are common in the main structure of the gas detoxification device 1, and can easily respond to various customer requirements by changing the design of the reducing agent supply system.

[0071] According to the second embodiment, a structure that does not use flammable high-pressure gas such as hydrogen can be provided, and therefore, for example, the degree of freedom in selecting the layout of the gas detoxification device 1 increases. The gas detoxification device 1 of Embodiment 1 or Embodiment 2 may be selected according to the installation location, usage frequency, safety management method, cost, etc. of the gas detoxification device 1 . That is, the range of available options can be expanded according to the usage conditions of the user.

[0072] (Implementation method 3) In the first and second embodiments, nitrogen oxides are exemplified as the detoxification target components of the gas to be treated, but the present invention is not limited to this. Hereinafter, an example in which the gas detoxification apparatus 1 is used and the detoxification target component of the gas to be processed is NF 3 which is a nitrogen compound will be described. The nitrogen compound (NF3) can be decomposed by heating in the internal reactor 4 in a state of being mixed with the reducing agent to remove the harm.

[0073] Figure 6 (A) shows the dependence of NF3 removal efficiency on hydrogen flow rate. Figure 6 (B) shows the dependence of NF3 removal efficiency on ethanol flow rate, Figure 6 (C) shows the dependence of the NF3 removal efficiency on the isopropyl alcohol (IPA) flow rate. Figure 6 It is also recorded that NO discharged from the gas detoxification device 1 x The vertical axis (left) is the NF3 removal efficiency (%), and the vertical axis (right) is the NO x Concentration (ppm). Figure 6 The horizontal axis of (A) is the hydrogen flow rate (SLM), Figure 6 The horizontal axis of (B) is ethanol flow rate (SCCM), Figure 6 The horizontal axis of (C) is IPA flow rate (SCCM). Figure 6In the figure, ◆ (solid diamond) indicates the pest control efficiency, ○ (hollow circle) indicates NO x The verification was conducted under the conditions of NF3 flow rate of 5 (SLM) and treatment temperature of 800°C.

[0074] like Figure 6 As shown, it can be understood that, although a high NF3 removal efficiency (about 100%) can be obtained in the absence of a reducing agent (hydrogen, ethanol, IPA), a high concentration of NOx is generated. However, it is understood that by introducing a reducing agent, NO can be significantly reduced. x concentration. It can be understood that by introducing the reducing agent, NO x The concentration was reduced to about 200 (ppm) or less. That is, it can be understood that when the nitrogen compound (NF3) was heated and decomposed, it reacted with the moisture (water vapor) retained in the chemical tank to generate NO at a high concentration. x However, by introducing a reducing agent into the internal reactor 4, NO x The generation of is significantly reduced. In addition, it can be understood that the margin for the flow rate of the reducing agent is large and the stability is high. Furthermore, the remaining reducing agent is combusted in the external reactor 5 .

[0075] Thus, according to the gas detoxification device 1, it is possible to suppress NO x At the same time as the exhaust, the gas containing nitrogen compounds as the detoxification target components is detoxified. Industrial Applicability

[0076] The gas detoxification device 1 involved in the present invention includes an internal reactor 4 for mixing a gas containing nitrous oxide as a nitrogen compound and the like as a detoxification target component with a reducing agent to thereby perform detoxification by thermal decomposition, and an external reactor 5 for burning the remaining reducing agent for detoxification. The combustion heat in the external reactor 5 can be recovered and reused as energy required for the reduction reaction in the internal reactor 4, thereby achieving energy saving. By using hydrogen as a reducing agent, the processing temperature range can be expanded to the lower temperature side. Furthermore, by changing the structure of the reducing agent introduction portion according to the form of the reducing agent (gas or liquid), it is also possible to contribute to, for example, expanding the installation range of the gas detoxification device 1. Compared with the conventional devices, the usable range of the gas detoxification device 1 can be expanded according to various requirements of users, and the industrial applicability is high. Description of Reference Numerals

[0077] 100 Gas Pest Control System 1 Gas detoxification device 2 Inlet scrubber 3. Outlet scrubber 4 Internal reactor (internal reactor, first reactor) 5 External reactor (external reactor, second reactor) 6 Internal reaction space (first reaction space) 7 Heating wall (reaction wall) 8Reducing gas supply port (gas supply port) 9 Piping (reducing gas supply line) 10 Gas inlet (processed gas inlet) 11 Gas outlet (purified gas outlet) 12 Gas outlet 13 Gas flow regulator 14 Support 14a Head 14b Shaft 15 Airflow control unit 16 External reaction space (second reaction space) 17 Insulation wall 18 Inlet 19 Piping 21 Inlet scrubber body 22 Nozzle 23 Gas inlet 24 Circulation Pipe 26 Gas outlet 30 Inlet 31. Exit scrubber body 32 Nozzle 33 Dilution port 34 Exhaust fan 40 Liquid tank 41 Drain valve 50 piping (introduction piping) 51 Discharge piping 90 Release section 91 Pipe (organic solvent supply line) 92 Pipe (Carrier gas supply line) 93 organic solvent container (box) 94 flow controller 95 bottles (gas containers) FPi Inflow FPo Outflow FCD Flow Control Device P Pump

Claims

1. A gas detoxification device (1), characterized in that: It has a first reactor (4) and a second reactor (5), The first reactor (4) has a first reaction space (6) surrounded by a heated wall (7), The second reactor (5) has a second reaction space (16) surrounding the heating wall (7), The gas and the reducing agent are introduced from one end of the first reaction space (6), The other end side of the first reaction space (6) is connected to the second reaction space (16). Oxygen or an oxygen-containing gas is introduced into the second reaction space (16).

2. The gas detoxification device (1) according to claim 1, characterized in that: The first reactor (4) has a gas flow regulator (13) in the first reaction space (6).

3. The gas detoxification device (1) according to claim 2, characterized in that: The heating wall (7) has a straight tube shape, The gas flow regulator (13) has a gas flow control unit (15). The length direction of the airflow control portion (15) is arranged to be parallel to the length direction of the heating wall (7).

4. The gas detoxification device (1) according to any one of claims 1 to 3, characterized in that: The reducing agent is a combustible gas.

5. The gas detoxification device (1) according to any one of claims 1 to 3, characterized in that: The reducing agent is an organic solvent.

6. A gas harm removal system (100), characterized in that: A gas detoxification device (1) according to any one of claims 1 to 3, an inlet scrubber (2) and an outlet scrubber (3), The inlet scrubber (2) is in communication with the first reactor (4), The outlet scrubber (3) is in communication with the second reactor (5).

7. A method for treating gas containing nitrous oxide, which is performed using the gas detoxification device (1) according to claim 1, characterized in that: include: a gas introduction step of introducing the gas into the first reactor (4); A reduction step of mixing the reducing agent introduced into the first reactor (4) with the gas and reducing the gas; a combustion step of introducing the gas after the reduction step and the remaining reducing agent into the second reactor (5) and reacting the oxygen introduced into the second reactor (5) with the remaining reducing agent; and A degassing step is performed to discharge the gas after the combustion step from the second reactor (5).

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