ระบบในการสลายไฮโดรเจนเปอร์ออกไซด์, ชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์ และวิธีการในการสลายของไฮโดรเจนเปอร์ออกไซด์

Abstract

DEPCT6726 / 07 / 2567 เพื่อสลายไฮโดรเจนเปอร์ออกไซด์ที่มีอยู่ในของเหลวที่จะถูกบำบัดอย่างมีประสิทธิภาพ ขณะที่ลดต้นทุนของอุปกรณ์ลงระบบในการสลายไฮโดรเจนเปอร์ออกไซด์ตามรูปแบบการประดิษฐ์ หนึ่งรวมเข้าไว้ด้วยจำนวนมากกว่าหนึ่งของชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์1,2,และ 3,ที่ซึ่งแต่ละชุดเครื่องของชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์รวมเข้าไว้ด้วย:ถังสลาย10 ซึ่งเก็บแอคติเวเทดคาร์บอน11สำหรับการสลายไฮโดรเจนเปอร์ออกไซด์ที่มีอยู่ในของเหลวที่จะถูก บำบัด;ถังเก็บ20ซึ่งเก็บของเหลวที่จะถูกบำบัดที่ถูกผ่านไปในแอคติเวเทดคาร์บอน11ในถังสลาย 10;และหน่วยหมุนเวียน / จัดป้อนของเหลวซึ่งจัดป้อนของเหลวที่จะถูกบำบัดที่ถูกเก็บไว้ในถังเก็บ20 ไปยังแอคติเวเทดคาร์บอน11,ระบบในการสลายไฮโดรเจนเปอร์ออกไซด์ถูกสร้างขึ้นในวิธี ในลักษณะที่เมื่อความเข้มข้นของไฮโดรเจนเปอร์ออกไซด์ของของเหลวที่จะถูกบำบัดในชุดเครื่อง ในการสลายไฮโดรเจนเปอร์ออกไซด์ขั้นสุดท้าย3จากในบรรดาจำนวนมากกว่าหนึ่งของชุดเครื่อง ในการสลายไฮโดรเจนเปอร์ออกไซด์1,2,และ3ลดลงมาถึงหรือต่ำกว่าความเข้มข้นเป้าหมาย, ของเหลวที่จะถูกบำบัดในชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์ขั้นสุดท้าย3ถูกปล่อยออก และของเหลวที่จะถูกบำบัดในแต่ละชุดเครื่องของชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์ 1และ2ที่นอกเหนือจากขั้นสุดท้ายถูกจัดป้อนไปยังชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์ ในขั้นต่อไป,และจำนวนมากกว่าหนึ่งของชุดเครื่องในการสลายไฮโดรเจนเปอร์ออกไซด์1,2,และ3 ถูกสร้างขึ้นในวิธีในลักษณะที่ของเหลวที่จะถูกบำบัดในแต่ละชุดเครื่องในการสลายไฮโดรเจนเปอร์ ออกไซด์จะหมุนเวียนที่อุณหภูมิที่ถูกระบุไว้หรือต่ำกว่า;

Description

Hydrogen peroxide decomposition system, hydrogen peroxide decomposition device, and hydrogen peroxide decomposition method

[0001] The present invention relates to a hydrogen peroxide decomposition system, a hydrogen peroxide decomposition device, and a method for decomposing hydrogen peroxide, and more particularly to a hydrogen peroxide decomposition system, a hydrogen peroxide decomposition device, and a method for decomposing hydrogen peroxide, which decompose hydrogen peroxide contained in a liquid to be treated and discharge a waste liquid containing hydrogen peroxide at a lower concentration.

[0002] Hydrogen peroxide is used in various industrial applications, such as bleaching paper pulp, cleaning processes in the manufacture of semiconductor substrates and pharmaceuticals, and etching circuit boards. The wastewater from these applications can contain high concentrations of hydrogen peroxide. High concentrations of hydrogen peroxide pose an explosion hazard and have a high chemical oxygen demand (COD). Therefore, it is necessary to decompose the hydrogen peroxide to reduce its concentration before discharging the wastewater.

[0003] In order to reduce the concentration of hydrogen peroxide contained in wastewater (hereinafter referred to as "liquid to be treated") before hydrogen peroxide decomposition treatment, a method and apparatus for decomposing hydrogen peroxide that utilizes a hydrogen peroxide decomposition reaction catalyzed by activated carbon are known. Patent Document 1 describes a method for decomposing hydrogen peroxide contained in a liquid to be treated using a decomposition tank containing granular activated carbon.

[0004] Japanese Unexamined Patent Publication No. 7-171561

[0005] The decomposition reaction of hydrogen peroxide generates reaction heat. In conventional methods, in order to withstand the reaction heat generated when decomposing a liquid containing high concentrations of hydrogen peroxide, materials with high heat resistance must be used in the decomposition tank, making the decomposition device expensive. Furthermore, when using the method described in Patent Document 1, the decomposition efficiency of hydrogen peroxide cannot be said to be sufficient.

[0006] The present invention was made based on the above technical recognition, and its object is to provide a hydrogen peroxide decomposition system, a hydrogen peroxide decomposition device, and a method for decomposing hydrogen peroxide that efficiently decomposes hydrogen peroxide contained in a liquid to be treated while reducing the cost of the device.

[0007] The hydrogen peroxide decomposition system of the present invention is a hydrogen peroxide decomposition system comprising a plurality of hydrogen peroxide decomposition devices, each of which comprises: a decomposition tank for storing activated carbon for decomposing hydrogen peroxide contained in a liquid to be treated; a storage tank for storing the liquid to be treated that has passed through the activated carbon in the decomposition tank; and a circulating liquid delivery section for delivering the liquid to be treated stored in the storage tank to the activated carbon; wherein when the hydrogen peroxide concentration of the liquid to be treated in a final hydrogen peroxide decomposition device among the plurality of hydrogen peroxide decomposition devices falls below a target concentration, the liquid to be treated in the final hydrogen peroxide decomposition device is discharged and the liquid to be treated in each hydrogen peroxide decomposition device other than the final one is delivered to the hydrogen peroxide decomposition device of the next stage; and wherein the plurality of hydrogen peroxide decomposition devices are configured so that the liquid to be treated in each hydrogen peroxide decomposition device is circulated at a specified temperature or below.

[0008] In addition, in the hydrogen peroxide decomposition system, the amount of activated carbon stored in the decomposition tanks of the multiple hydrogen peroxide decomposition devices may be such that, for at least a first decomposition tank at the top and a second decomposition tank downstream of the first decomposition tank, the amount of activated carbon stored in the first decomposition tank is less than the amount of activated carbon stored in the second decomposition tank.

[0009] In the hydrogen peroxide decomposition system, the amount of activated carbon stored in the decomposition tanks of the plurality of hydrogen peroxide decomposition devices may monotonically increase from the upstream hydrogen peroxide decomposition device to the downstream hydrogen peroxide decomposition device.

[0010] In addition, in the hydrogen peroxide decomposition system, the number of the plurality of hydrogen peroxide decomposition devices may be three or more, and the amount of activated carbon stored in the decomposition tanks of at least two or more of the plurality of hydrogen peroxide decomposition devices may be the same.

[0011] In the hydrogen peroxide decomposition system, the amount of the liquid to be treated delivered by the circulation liquid delivery sections of the plurality of hydrogen peroxide decomposition devices may be such that, for at least a first circulation liquid delivery section at the top and a second circulation liquid delivery section downstream of the first circulation liquid delivery section, the amount of the liquid to be treated delivered by the first circulation liquid delivery section is less than the amount of the liquid to be treated delivered by the second circulation liquid delivery section.

[0012] In the hydrogen peroxide decomposition system, at least one of the plurality of hydrogen peroxide decomposition devices may further include a cooler that cools the liquid to be treated.

[0013] In the hydrogen peroxide decomposition system, the decomposition tanks of the plurality of hydrogen peroxide decomposition devices may be made of heat-resistant resin.

[0014] In the hydrogen peroxide decomposition system, the number of the plurality of hydrogen peroxide decomposition devices may be 2 to 8.

[0015] Furthermore, in the hydrogen peroxide decomposition system, the multiple hydrogen peroxide decomposition devices may be connected by an inter-device liquid transfer section provided between each of the hydrogen peroxide decomposition devices, the inter-device liquid transfer section connecting the outlet of a first hydrogen peroxide decomposition device to the inlet of a second hydrogen peroxide decomposition device located in the next stage after the first hydrogen peroxide decomposition device.

[0016] In addition, in the hydrogen peroxide decomposition system, the inter-device liquid transfer section may include: a liquid transfer pipe connecting the outlet of the first hydrogen peroxide decomposition device and the inlet of the second hydrogen peroxide decomposition device; and an inter-device pump provided in the liquid transfer pipe for transferring the liquid to be treated from the first hydrogen peroxide decomposition device to the second hydrogen peroxide decomposition device.

[0017] Furthermore, in the hydrogen peroxide decomposition system, the circulation liquid feed section of each of the hydrogen peroxide decomposition devices may include: a liquid feed pipe for feeding the liquid to be treated from an outlet provided in the storage tank of the first hydrogen peroxide decomposition device to the activated carbon of the first hydrogen peroxide decomposition device or to the second hydrogen peroxide decomposition device; a circulation pump provided in the liquid feed pipe; and a switching section provided in the liquid feed pipe for switching whether the liquid to be treated discharged from the circulation pump is fed from the outlet to the activated carbon of the first hydrogen peroxide decomposition device or from the outlet to the second hydrogen peroxide decomposition device.

[0018] The hydrogen peroxide decomposition apparatus according to the present invention is characterized by comprising: a decomposition tank that stores activated carbon for decomposing hydrogen peroxide contained in a liquid to be treated; a storage tank that stores the liquid to be treated that has passed through the activated carbon in the decomposition tank; and a circulation liquid delivery section that delivers the liquid to be treated stored in the storage tank to the activated carbon.

[0019] In the hydrogen peroxide decomposition apparatus, the storage tank may be disposed below the decomposition tank, and the liquid to be treated that has passed through the activated carbon in the decomposition tank may freely fall into the storage tank.

[0020] In the hydrogen peroxide decomposition apparatus, the circulation liquid sending section may have a sprayer that sprays the liquid to be treated onto the activated carbon.

[0021] In the hydrogen peroxide decomposition device, the circulation liquid supply section may include a concentration measuring device that measures the concentration of hydrogen peroxide.

[0022] The hydrogen peroxide decomposition device may further include an exhaust port for discharging oxygen produced by the decomposition of hydrogen peroxide.

[0023] In the hydrogen peroxide decomposition device, the activated carbon may be in a granular form.

[0024] In the hydrogen peroxide decomposition apparatus, the decomposition tank may further include a filter on which the activated carbon is placed, and a support portion that supports the filter.

[0025] The hydrogen peroxide decomposition apparatus may further include a temperature sensor that measures the temperature of the liquid to be treated, and a control unit that controls the circulation liquid supply unit and stops the liquid supply from the circulation liquid supply unit when the temperature measured by the temperature sensor exceeds a dangerous temperature.

[0026] The hydrogen peroxide decomposition apparatus may further include a cooler that cools the liquid to be treated stored in the storage tank.

[0027] The hydrogen peroxide decomposition apparatus may further include a temperature sensor that measures the temperature of the liquid to be treated, and a control unit that controls the operation of the cooler, the control unit starting the operation of the cooler when the temperature measured by the temperature sensor exceeds a dangerous temperature.

[0028] The method for decomposing hydrogen peroxide according to the present invention is a method for decomposing hydrogen peroxide using a hydrogen peroxide decomposition system comprising a plurality of hydrogen peroxide decomposition devices, wherein each of the hydrogen peroxide decomposition devices in the hydrogen peroxide decomposition system comprises a decomposition tank for storing activated carbon for decomposing hydrogen peroxide contained in a liquid to be treated, a storage tank for storing the liquid to be treated that has passed through the activated carbon in the decomposition tank, and a liquid circulation section for sending the liquid to be treated stored in the storage tank to the activated carbon, wherein the plurality of hydrogen peroxide decomposition devices are configured so that the liquid to be treated in each of the hydrogen peroxide decomposition devices is circulated at or below a specified temperature, and wherein when the hydrogen peroxide concentration of the liquid to be treated in a final stage of the plurality of hydrogen peroxide decomposition devices falls below a target concentration, the liquid to be treated in the final stage hydrogen peroxide decomposition device is discharged and the liquid to be treated in each of the hydrogen peroxide decomposition devices other than the final stage is sent to the hydrogen peroxide decomposition device of the next stage, and wherein the hydrogen peroxide decomposition method continues until the hydrogen peroxide concentration of the liquid to be treated in the hydrogen peroxide decomposition device of the final stage falls below the target concentration. Each of the hydrogen peroxide decomposition devices repeats the process of passing the liquid to be treated through the activated carbon, storing the liquid that has passed through the activated carbon in the storage tank, sending the liquid to be treated stored in the storage tank using the circulation liquid sending unit, and passing the liquid through the activated carbon again; and when the hydrogen peroxide concentration of the liquid to be treated in the hydrogen peroxide decomposition device of the final stage falls below a target concentration, each of the hydrogen peroxide decomposition devices stops the liquid sending by the circulation liquid sending unit, discharges the liquid to be treated from the hydrogen peroxide decomposition device of the final stage, and sends the liquid to be treated in each of the hydrogen peroxide decomposition devices other than the final stage to the hydrogen peroxide decomposition device of the next stage.

[0029] According to the present invention, it is possible to provide a hydrogen peroxide decomposition system, a hydrogen peroxide decomposition device, and a hydrogen peroxide decomposition method that efficiently decompose hydrogen peroxide contained in a liquid to be treated while reducing the cost of the device.

[0030] 1 is a diagram showing the configuration of a hydrogen peroxide decomposition system according to a first embodiment; FIG. 2 is a diagram showing the configuration of a hydrogen peroxide decomposition device according to a first embodiment; FIG. 3 is a flowchart illustrating an example of the operation of a hydrogen peroxide decomposition system according to an embodiment; FIG. 4 is a graph showing the relationship between hydrogen peroxide concentration and temperature rise; FIG. 5 is a graph showing the relationship between activated carbon concentration and temperature rise; FIG. 6 is a graph showing the relationship between hydrogen peroxide concentration and decomposition rate; FIG. 7 is a graph showing the relationship between activated carbon concentration and decomposition rate; FIG. 8 is a diagram showing the configuration of a hydrogen peroxide decomposition system according to a second embodiment; FIG. 9 is a diagram showing the configuration of a hydrogen peroxide decomposition system according to a third embodiment;

[0031] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, components having equivalent functions are designated by the same reference numerals. The scale of each component has been appropriately changed so that it can be recognized on the drawing.

[0032] (First Embodiment) A hydrogen peroxide decomposition system and a hydrogen peroxide decomposition device according to a first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing the configuration of a hydrogen peroxide decomposition system according to this embodiment. Figure 2 is a diagram showing the configuration of a hydrogen peroxide decomposition device according to this embodiment.

[0033] <Hydrogen Peroxide Decomposition System> The hydrogen peroxide decomposition system 100 is a system that decomposes hydrogen peroxide contained in a liquid to be treated and discharges effluent containing hydrogen peroxide at a lower concentration.

[0034] 1 , hydrogen peroxide decomposition system 100 according to this embodiment includes multiple hydrogen peroxide decomposition devices 1, 2, and 3, multiple inter-device liquid transfer units 40, and control unit 50. Hydrogen peroxide decomposition system 100 is also connected to a tank 200 for a liquid to be treated and a tank 300 for waste liquid.

[0035] The hydrogen peroxide decomposition devices 1, 2, and 3 are configured to decompose hydrogen peroxide contained in the liquid to be treated. Details of the hydrogen peroxide decomposition devices 1, 2, and 3 will be described later.

[0036] In this embodiment, hydrogen peroxide decomposition apparatuses 1, 2, and 3 are daisy-chained (so-called daisy-chained) via inter-apparatus liquid transfer unit 40. That is, hydrogen peroxide decomposition apparatus 2 is connected to the next stage of hydrogen peroxide decomposition apparatus 1 via inter-apparatus liquid transfer unit 40. Furthermore, hydrogen peroxide decomposition apparatus 3 is connected to the next stage of hydrogen peroxide decomposition apparatus 2 via inter-apparatus liquid transfer unit 40.

[0037] Inter-device liquid transfer section 40 is configured to transfer the liquid to be treated from one hydrogen peroxide decomposition apparatus to the hydrogen peroxide decomposition apparatus located in the next stage (inter-device liquid transfer). Inter-device liquid transfer section 40 between hydrogen peroxide decomposition apparatus 1 and hydrogen peroxide decomposition apparatus 2 transfers the liquid to be treated from hydrogen peroxide decomposition apparatus 1 to hydrogen peroxide decomposition apparatus 2. Inter-device liquid transfer section 40 between hydrogen peroxide decomposition apparatus 2 and hydrogen peroxide decomposition apparatus 3 transfers the liquid to be treated from hydrogen peroxide decomposition apparatus 2 to hydrogen peroxide decomposition apparatus 3.

[0038] The inter-device liquid transfer section 40 includes a liquid transfer pipe 41 , an inter-device pump 42 , and a valve 43 .

[0039] Liquid feed pipe 41 connects outlet 22 (described below) of one hydrogen peroxide decomposition apparatus to inlet 21 (described below) of the next hydrogen peroxide decomposition apparatus. Specifically, liquid feed pipe 41 of inter-apparatus liquid feed section 40 between hydrogen peroxide decomposition apparatuses 1 and 2 connects outlet 22 of hydrogen peroxide decomposition apparatus 1 to inlet 21 of hydrogen peroxide decomposition apparatus 2. Furthermore, liquid feed pipe 41 of inter-apparatus liquid feed section 40 between hydrogen peroxide decomposition apparatuses 2 and 3 connects outlet 22 of hydrogen peroxide decomposition apparatus 2 to inlet 21 of hydrogen peroxide decomposition apparatus 3.

[0040] Inter-apparatus pump 42 is provided in liquid feed pipe 41 and feeds the liquid to be treated from one hydrogen peroxide decomposition apparatus to the next hydrogen peroxide decomposition apparatus through liquid feed pipe 41. In this embodiment, inter-apparatus pump 42 starts operating when inter-apparatus liquid feed is started and stops operating when inter-apparatus liquid feed is stopped, under the control of control unit 50 (described below). Inter-apparatus pump 42 is, for example, a positive displacement pump or a non-positive displacement pump.

[0041] The valve 43 is provided in the liquid transfer pipe 41 upstream of the inter-apparatus pump 42. In this embodiment, the valve 43 is a solenoid valve, which opens when inter-apparatus liquid transfer starts under the control of the control unit 50 and closes when inter-apparatus liquid transfer stops.

[0042] The configuration of inter-apparatus liquid transfer unit 40 is not limited to that shown in Fig. 1. For example, valve 43 may be provided downstream of inter-apparatus pump 42. Alternatively, a check valve may be provided in liquid transfer pipe 41 instead of or in addition to valve 43. Inter-apparatus liquid transfer unit 40 may also have multiple inter-apparatus pumps 42 and / or multiple valves 43. Furthermore, multiple inter-apparatus liquid transfer units 40 may be provided between two hydrogen peroxide decomposition devices.

[0043] In this embodiment, hydrogen peroxide decomposition devices 1, 2, and 3 each have a different amount of activated carbon 11. Specifically, the amount of activated carbon 11 is the smallest in hydrogen peroxide decomposition device 1, which is the top stage, increases downstream, and is greatest in hydrogen peroxide decomposition device 3, which is the final stage. The amount of activated carbon 11 will be described in detail later.

[0044] The tank 200 stores a liquid to be treated that contains a high concentration of hydrogen peroxide (for example, 12 to 35%).

[0045] Tank 200 for the liquid to be treated is connected to the hydrogen peroxide decomposition device at the top of hydrogen peroxide decomposition system 100. In this embodiment, tank 200 for the liquid to be treated is connected to inlet 21 of hydrogen peroxide decomposition device 1 via liquid feed pipe 201. Liquid feed pipe 201 is provided with valve 203. Valve 203 is an electromagnetic valve that, under the control of control unit 50, opens when liquid feed from tank 200 for the liquid to be treated begins and closes when the liquid feed is stopped. A pump may be provided in liquid feed pipe 201.

[0046] Wastewater tank 300 stores the liquid to be treated, whose hydrogen peroxide concentration has been reduced to a predetermined level or lower by hydrogen peroxide decomposition system 100. Here, the "predetermined concentration" refers to the hydrogen peroxide concentration determined for hydrogen peroxide decomposition system 100, such as a concentration determined by the wastewater standards for hydrogen peroxide (e.g., 2%).

[0047] Drain tank 300 is connected to the hydrogen peroxide decomposition device in the final stage of hydrogen peroxide decomposition system 100. In this embodiment, drain tank 300 is connected via liquid feed pipe 301 to outlet 22 of hydrogen peroxide decomposition device 3 in the final stage of hydrogen peroxide decomposition system 100. Pump 302 and valve 303 are provided in liquid feed pipe 301. Pump 302 starts operating when liquid feed (discharge) to drain tank 300 is initiated under the control of control unit 50, and stops operating when liquid feed is stopped. Pump 302 is, for example, a positive displacement pump or a non-positive displacement pump. Valve 303 is an electromagnetic valve that opens when liquid feed from tank 200 to be treated is initiated under the control of control unit 50, and closes when liquid feed is stopped. Pump 302 need not be provided.

[0048] Control unit 50 controls each pump and each valve of hydrogen peroxide decomposition system 100. In this embodiment, control unit 50 controls inter-device pump 42 and valve 43 of inter-device liquid transfer unit 40, as well as valve 203, pump 302, and valve 303. Control unit 50 also controls circulation pump 32 and valve 34 of circulating liquid transfer unit 30, which will be described later.

[0049] Furthermore, control unit 50 acquires the hydrogen peroxide concentration of the liquid to be treated in each of hydrogen peroxide decomposition devices 1 to 3 from float sensor 23 and concentration measuring device 35 (described later) of each device. Based on the values ​​output by float sensor 23 and concentration measuring device 35, control unit 50 controls the start / stop of each pump and the opening / closing of each valve.

[0050] In the above description, the pumps, valves, sensors, etc. of hydrogen peroxide decomposition system 100 are controlled by a common controller 50. However, this is not limited to this, and each hydrogen peroxide decomposition device may have its own device controller that controls the pumps, valves, and sensors of the hydrogen peroxide decomposition device. In this case, controller 50 may be connected to the device controllers of each hydrogen peroxide decomposition device to centrally manage each device controller.

[0051] Furthermore, the control unit 50 may be connected to each pump, each valve, each sensor, measuring instrument, etc. by wire or wirelessly.

[0052] <Hydrogen Peroxide Decomposition Apparatus> Next, the hydrogen peroxide decomposition apparatuses 1, 2, and 3 will be described in detail with reference to FIG.

[0053] The hydrogen peroxide decomposition devices 1, 2, and 3 each include a decomposition tank 10 that decomposes hydrogen peroxide contained in the liquid to be treated, a storage tank 20 that stores the liquid to be treated, and a circulating liquid delivery section 30 that delivers the liquid to be treated from the storage tank 20 to the decomposition tank 10.

[0054] Decomposition tank 10 includes activated carbon 11, a filter 12, a support 13, an exhaust port 14, and a temperature sensor 15. The container of decomposition tank 10 is made of a heat-resistant resin such as acrylic or vinyl chloride.

[0055] Activated carbon 11 is stored in decomposition tank 10 and decomposes hydrogen peroxide contained in the liquid to be treated. More specifically, when the liquid to be treated comes into contact with activated carbon 11, a decomposition reaction of hydrogen peroxide occurs with the activated carbon as a catalyst, and the hydrogen peroxide contained in the liquid to be treated is decomposed. By using a decomposition reaction catalyzed by activated carbon, the cost of the decomposition treatment can be reduced compared to methods that use electrolysis or methods that use a metal catalyst such as platinum, a reducing agent such as sodium bisulfite or sodium thiosulfate, a metal oxide such as manganese dioxide, or an enzyme such as catalase.

[0056] The activated carbon 11 is, for example, granular activated carbon with an average particle size of about 1 mm. By using granular activated carbon, the surface area of ​​the activated carbon increases, thereby improving the efficiency of decomposing hydrogen peroxide. Note that the activated carbon 11 may also be a block of activated carbon with many through-holes (for example, an activated carbon honeycomb).

[0057] The filter 12 is a filter with fine pores (for example, a vinyloc filter). The activated carbon 11 is placed on the filter 12. Providing the filter 12 in the decomposition tank 10 prevents fine particles of activated carbon from falling into the storage tank 20 and causing a decomposition reaction inside the storage tank 20. Note that if the activated carbon 11 is a block-shaped activated carbon, for example, the filter 12 may not be provided.

[0058] The support portion 13 supports the activated carbon 11 and the filter 12. The support portion 13 is, for example, a mesh plate, which can support the activated carbon 11 while allowing the liquid to pass through.

[0059] The exhaust port 14 discharges oxygen gas produced by the decomposition of hydrogen peroxide. Providing the exhaust port 14 in the decomposition tank 10 prevents the air pressure inside the apparatus from increasing and damaging the apparatus. The exhaust port 14 may be provided in the storage tank 20, but is preferably provided in the upper part of the decomposition tank 10, as shown in FIG. 2. Alternatively, instead of or in addition to the exhaust port 14, the decomposition tank 10 and / or the storage tank 20 may have a non-sealed structure.

[0060] The temperature sensor 15 measures the temperature of the liquid to be treated in the decomposition tank 10. In this embodiment, the temperature sensor 15 is provided at the bottom of the decomposition tank 10. The temperature sensor 15 outputs the measured value to the control unit 50. By providing the temperature sensor 15 at the bottom of the decomposition tank 10, most of the liquid to be treated that has passed through the activated carbon 11 comes into contact with the temperature sensor 15, allowing the temperature of the liquid to be treated to be measured appropriately. For this reason, the temperature sensor 15 may output the average value of the measured temperature for each predetermined time period to the control unit 50. The temperature sensor 15 may also be provided at a location other than the bottom of the decomposition tank 10.

[0061] The storage tank 20 stores the liquid to be treated that has passed through the activated carbon 11 in the decomposition tank 10. The container of the storage tank 20 is made of a heat-resistant resin such as acrylic or vinyl chloride. In this embodiment, the storage tank 20 is located below the decomposition tank 10, and the liquid to be treated that has passed through the activated carbon 11 in the decomposition tank 10 falls freely into the storage tank 20.

[0062] In this embodiment, the decomposition tank 10 is connected to the top of the storage tank 20, but this is not limiting. For example, the decomposition tank 10 may be suspended above the storage tank 20, providing a space between the decomposition tank 10 and the storage tank 20. Alternatively, the storage tank 20 may be located somewhere other than below the decomposition tank 10, and the decomposition tank 10 and the storage tank 20 may be connected by a pipe or the like.

[0063] The storage tank 20 has an intake port 21 , an outlet port 22 , a float sensor 23 , a cooler 24 , a temperature sensor 25 , and a circulation outlet port 26 .

[0064] The inlet 21 is a hole for allowing the liquid to be treated to flow into the storage tank 20. As described above, the inlet 21 is connected to the liquid transfer pipe 41 of the inter-apparatus liquid transfer section 40 or the liquid transfer pipe 201. In this embodiment, the inlet 21 is provided in the upper part of the storage tank 20. Note that, if a space is provided between the decomposition tank 10 and the storage tank 20, the inlet 21 may be provided between the decomposition tank 10 and the storage tank 20. Alternatively, the inlet 21 may be provided in the decomposition tank 10, and the liquid to be treated may flow into the decomposition tank 10.

[0065] The outlet 22 is a hole for allowing the liquid to be treated to flow out of the storage tank 20. As described above, the outlet 22 is connected to the liquid transfer pipe 41 of the inter-device liquid transfer section 40 or the liquid transfer pipe 301. In this embodiment, the outlet 22 is provided at the bottom of the side surface of the storage tank 20. Note that the outlet 22 may also be provided on the bottom surface of the storage tank 20.

[0066] The float sensor 23 is a sensor (liquid level sensor) for measuring the amount of the liquid to be treated stored in the storage tank 20. In this embodiment, the float sensor 23 outputs the measured value to the control unit 50.

[0067] The cooler 24 cools the liquid to be treated stored in the storage tank 20. In this embodiment, the cooler 24 is a chiller that is arranged so as to be immersed in the liquid to be treated inside the storage tank 20. By providing the hydrogen peroxide decomposition apparatus with the cooler 24, it is possible to easily maintain the temperature of the liquid to be treated at or below a specified temperature.

[0068] The temperature sensor 25 measures the temperature of the liquid to be treated in the storage tank 20. In this embodiment, the temperature sensor 25 is provided at the bottom of the storage tank 20. The temperature sensor 25 also outputs the measured value to the control unit 50. By providing the temperature sensor 25 at the bottom of the storage tank 20, the temperature of the liquid to be treated can be properly measured even when the amount of liquid to be treated stored in the storage tank 20 is small. The temperature sensor 25 may also be provided at a location other than the bottom of the storage tank 20.

[0069] The circulation outlet 26 is a hole through which the liquid to be treated flows out so that the liquid to be treated is circulated within the apparatus by the circulation liquid sending unit 30. In this embodiment, the circulation outlet 26 is provided in the lower part of the side surface of the storage tank 20. The circulation outlet 26 may also be provided in the bottom surface of the storage tank 20.

[0070] The circulating liquid sending unit 30 is configured to send (circulate) the liquid to be treated stored in the storage tank 20 to the activated carbon 11. In this embodiment, the circulating liquid sending unit 30 sends the liquid to be treated above the activated carbon 11. However, this is not limited thereto, and the liquid to be treated may be sent to the lower or side of the activated carbon 11, the center of stored granular activated carbon, or into the through-holes of a block of activated carbon.

[0071] The circulation liquid sending section 30 includes a liquid sending pipe 31 , a circulation pump 32 , a spray 33 , a valve 34 , and a concentration measuring device 35 .

[0072] The liquid feed pipe 31 is a pipe for feeding the liquid to be treated from the circulation discharge port 26 to the activated carbon 11. More specifically, the liquid feed pipe 31 is a pipe for feeding the liquid to be treated from the circulation discharge port 26 provided in the storage tank 20 to the activated carbon 11 via a spray 33. One end of the liquid feed pipe 31 is connected to the circulation discharge port 26, and the other end is disposed at the top of the decomposition tank 10. The other end of the liquid feed pipe 31 is provided with a plurality of spray holes.

[0073] The circulation pump 32 is provided in the liquid feed pipe 31 and feeds the liquid to be treated through the liquid feed pipe 31. In this embodiment, the circulation pump 32 starts its operation when the circulating liquid feed is started and stops its operation when the circulating liquid feed is stopped under the control of the control unit 50. The circulation pump 32 is, for example, a positive displacement pump or a non-positive displacement pump.

[0074] The spray 33 is used to spray the liquid to be treated onto the activated carbon 11. The liquid to be treated sent by the circulation pump 32 is sprayed from the spray 33 and comes into contact with the activated carbon 11. The spray 33 may be configured by a plurality of through-holes (spray holes) provided in the liquid sending pipe 31, or may be configured by a spray nozzle (not shown) attached to the liquid sending pipe 31.

[0075] The valve 34 is provided upstream of the circulation pump 32 in the liquid supply pipe 31. In this embodiment, the valve 34 is an electromagnetic valve that opens when the circulation supply is started and closes when the circulation supply is stopped under the control of the control unit 50.

[0076] The concentration measuring device 35 measures the concentration of hydrogen peroxide contained in the liquid to be treated. As the concentration measuring device 35, an in-line hydrogen peroxide monitor or the like may be used, as shown in Figure 2. In this embodiment, the concentration measuring device 35 outputs the measured value to the control unit 50.

[0077] The configuration of the circulation liquid supply unit 30 is not limited to that shown in Figures 1 and 2. For example, the circulation pump 32 and the valve 34 may be located at the same height as the circulation outlet 26. The valve 34 may be provided downstream of the circulation pump 32. A check valve may be provided in the liquid supply pipe 31 instead of or in addition to the valve 34. Furthermore, a concentration measuring device 35 may be provided upstream of the circulation pump 32.

[0078] Furthermore, the circulation liquid sending unit 30 may have a plurality of circulation pumps 32 and / or a plurality of valves 34. Furthermore, a plurality of circulation liquid sending units 30 may be provided in one hydrogen peroxide decomposition device.

[0079] Next, the operation of the hydrogen peroxide decomposition devices 1 to 3 will be described.

[0080] First, the liquid to be treated flows into the storage tank 20 through the inlet 21 provided therein and is stored therein. The stored liquid to be treated is sent by the circulation liquid sending unit 30 to the activated carbon 11 stored in the decomposition tank 10. More specifically, the liquid to be treated is sent by the circulation pump 32 of the circulation liquid sending unit 30 through the circulation outlet 26 to the spray 33, and is sprayed from the spray 33. The liquid to be treated sprayed from the spray 33 comes into contact with the activated carbon 11. When the liquid to be treated comes into contact with the activated carbon 11, a decomposition reaction of hydrogen peroxide occurs with the activated carbon as a catalyst. This decomposition reaction decomposes at least a portion of the hydrogen peroxide contained in the liquid to be treated into water and oxygen gas. At the same time, reaction heat (decomposition heat) is generated by the decomposition reaction.

[0081] The liquid to be treated (including water produced by the decomposition reaction) that has passed through activated carbon 11 is stored in storage tank 20. The stored liquid to be treated is sent again to activated carbon 11 by circulation liquid sending section 30. In this way, the liquid to be treated circulates between decomposition tank 10 and storage tank 20 of the hydrogen peroxide decomposition apparatus, so that the liquid to be treated repeatedly comes into contact with activated carbon 11, the hydrogen peroxide contained in the liquid to be treated is decomposed, and the hydrogen peroxide concentration of the liquid to be treated decreases.

[0082] <Method for Decomposing Hydrogen Peroxide Using a Hydrogen Peroxide Decomposition System> A method for decomposing hydrogen peroxide using a hydrogen peroxide decomposition system 100 according to this embodiment will be described with reference to Figures 1 and 3. Figure 3 is a flowchart illustrating an example of the operation of the hydrogen peroxide decomposition system 100 according to this embodiment.

[0083] In the following description, it is assumed that at the start of operation, the liquid to be treated is circulating in each of hydrogen peroxide decomposition devices 1, 2, and 3. More specifically, it is assumed that hydrogen peroxide decomposition devices 1, 2, and 3 pass the liquid to be treated through activated carbon 11, store the liquid that has passed through activated carbon 11 in storage tank 20, and then use liquid circulation supply unit 30 to supply the liquid to be treated stored in storage tank 20 and pass it through activated carbon 11 again, repeatedly.

[0084] First, the control unit 50 determines whether the hydrogen peroxide concentration in the liquid to be treated in the final-stage hydrogen peroxide decomposition device 3 is equal to or less than the target concentration (step S1). The control unit 50 reads the value output by the concentration measuring device 35 in the hydrogen peroxide decomposition device 3 and determines whether the value is equal to or less than the target concentration. In this embodiment, the target concentration is the "predetermined concentration" described above.

[0085] If it is determined that the hydrogen peroxide concentration in the liquid being treated in the final-stage hydrogen peroxide decomposition device 3 has not reached the target concentration or less (step S1: No), step S1 is executed again after a predetermined time has elapsed, during which time the hydrogen peroxide decomposition devices 1, 2, and 3 continue to circulate the liquid being treated.

[0086] On the other hand, when it is determined that the hydrogen peroxide concentration of the liquid being treated in the final-stage hydrogen peroxide decomposition device 3 has fallen below the target concentration (Step S1: Yes), the control unit 50 stops the liquid supply by the circulation liquid supply units 30 of the hydrogen peroxide decomposition devices 1, 2, and 3 (Step S2). More specifically, the control unit 50 stops the operation of all circulation pumps 32 and closes all valves 34 of the hydrogen peroxide decomposition devices 1, 2, and 3.

[0087] Next, the liquid to be treated from the final-stage hydrogen peroxide decomposition device 3 is discharged into wastewater tank 300, and the liquid to be treated from the hydrogen peroxide decomposition devices 1 and 2 other than the final stage is sent to the hydrogen peroxide decomposition device in the next stage, starting with the hydrogen peroxide decomposition device located downstream (Step S3). Step S3 is described in detail below.

[0088] First, the control unit 50 starts discharging the liquid to be treated contained in the final-stage hydrogen peroxide decomposition device 3. More specifically, the control unit 50 opens the valve 303 and starts the operation of the pump 302. This causes the liquid to be treated contained in the hydrogen peroxide decomposition device 3 to be discharged.

[0089] Next, the control unit 50 determines whether the discharge of the liquid to be treated is complete. Specifically, the control unit 50 reads the value of the float sensor 23 of the hydrogen peroxide decomposition device 3, and determines that the discharge of the liquid to be treated is complete, for example, if the value is equal to or less than a value indicating that the storage tank 20 of the hydrogen peroxide decomposition device 3 is empty.

[0090] If it is determined that the discharge of the liquid to be treated is not complete, the determination is made again after a predetermined time has elapsed, during which time the discharge of the liquid to be treated continues.

[0091] On the other hand, if it is determined that the discharge of the liquid to be treated has been completed, the control unit 50 stops the discharge of the liquid to be treated contained in the hydrogen peroxide decomposition device 3. More specifically, the control unit 50 stops the operation of the pump 302 and closes the valve 303.

[0092] Next, the liquid to be treated is sent (inter-apparatus liquid transfer) to the final-stage hydrogen peroxide decomposition apparatus 3. More specifically, the liquid to be treated is sent from hydrogen peroxide decomposition apparatus 2, which is located upstream of hydrogen peroxide decomposition apparatus 3, to hydrogen peroxide decomposition apparatus 3 via inter-apparatus liquid transfer unit 40. Specifically, control unit 50 opens valve 43 of inter-apparatus liquid transfer unit 40, which connects hydrogen peroxide decomposition apparatus 2 and hydrogen peroxide decomposition apparatus 3, and starts operation of inter-apparatus pump 42.

[0093] Next, control unit 50 determines whether the liquid transfer is complete. Control unit 50 reads the value (first value) of float sensor 23 provided in storage tank 20 of hydrogen peroxide decomposition device 3 and the value (second value) of float sensor 23 provided in storage tank 20 of hydrogen peroxide decomposition device 2, and determines that the liquid transfer is complete if, for example, the first value is equal to or greater than the value indicating that storage tank 20 of hydrogen peroxide decomposition device 3 is full, or the second value is equal to or less than the value indicating that storage tank 20 of hydrogen peroxide decomposition device 2 is empty.

[0094] If it is determined that the liquid transfer is not complete, the determination is made again after a predetermined time has elapsed, during which time the liquid transfer continues.

[0095] On the other hand, if it is determined that the liquid transfer has been completed, the liquid transfer is stopped. More specifically, the control unit 50 stops the operation of the inter-apparatus pump 42 of the inter-apparatus liquid transfer unit 40 that connects the hydrogen peroxide decomposition apparatus 2 and the hydrogen peroxide decomposition apparatus 3, and closes the valve 43.

[0096] Next, a similar process is performed to transfer the liquid to be treated from hydrogen peroxide decomposition apparatus 1 to hydrogen peroxide decomposition apparatus 2. Control unit 50 reads the value (third value) of float sensor 23 provided in storage tank 20 of hydrogen peroxide decomposition apparatus 2 and the value (fourth value) of float sensor 23 provided in storage tank 20 of hydrogen peroxide decomposition apparatus 1, and determines that the transfer of the liquid is complete when, for example, the third value is equal to or greater than the value indicating that storage tank 20 of hydrogen peroxide decomposition apparatus 2 is full, or the fourth value is equal to or less than the value indicating that storage tank 20 of hydrogen peroxide decomposition apparatus 1 is empty.

[0097] Next, a similar process is performed to cause the liquid to be treated to flow from tank 200 into hydrogen peroxide decomposition apparatus 1. Control unit 50 reads the value of float sensor 23 provided in storage tank 20 of hydrogen peroxide decomposition apparatus 1, and determines that the transfer of liquid from tank 200 to hydrogen peroxide decomposition apparatus 1 has been completed when, for example, this value is equal to or greater than a value indicating that storage tank 20 of hydrogen peroxide decomposition apparatus 1 is full.

[0098] After the liquid has been transferred between the devices as described above, control unit 50 starts liquid transfer (circulation liquid transfer) by circulation liquid transfer units 30 of hydrogen peroxide decomposition devices 1, 2, and 3 (step S4). More specifically, control unit 50 opens all valves 34 of hydrogen peroxide decomposition devices 1, 2, and 3 and starts the operation of all circulation pumps 32. After step S4, the process returns to step S1.

[0099] By repeating the above steps S1 to S4, hydrogen peroxide decomposition system 100 can decompose the hydrogen peroxide contained in the liquid to be treated and discharge the liquid to be treated at a concentration equal to or lower than the target concentration as wastewater.

[0100] Alternatively, the determination in step S1 may be made as to whether the hydrogen peroxide concentration in the liquid to be treated has reached or exceeded a target concentration for each of hydrogen peroxide decomposition devices 1, 2, and 3. In this case, a first target concentration, a second target concentration, and a third target concentration are preset for hydrogen peroxide decomposition device 1, hydrogen peroxide decomposition device 2, and hydrogen peroxide decomposition device 3, respectively. In step S1, if the hydrogen peroxide concentration in hydrogen peroxide decomposition device 1 is equal to or lower than the first target concentration, the hydrogen peroxide concentration in hydrogen peroxide decomposition device 2 is equal to or lower than the second target concentration, and the hydrogen peroxide concentration in hydrogen peroxide decomposition device 3 is equal to or lower than the third target concentration, the process proceeds to step S2. Here, the second target concentration is equal to or lower than the first target concentration, and the third target concentration is equal to or lower than the second target concentration.

[0101] The determination in step S1 may also be made based on the temperature inside the hydrogen peroxide decomposition apparatus. In this case, the value output by temperature sensor 15 provided in decomposition tank 10 of hydrogen peroxide decomposition apparatus 3 is used instead of the value output by concentration measuring instrument 35. When the hydrogen peroxide concentration decreases and the decomposition reaction of hydrogen peroxide stops progressing, the temperature inside the hydrogen peroxide decomposition apparatus decreases compared to when the decomposition reaction is progressing. Therefore, for example, when the value output by temperature sensor 15 falls below a threshold, control unit 50 may determine that the hydrogen peroxide concentration of the liquid being treated in hydrogen peroxide decomposition apparatus 3 has fallen below the target concentration. Note that the output value of temperature sensor 25 provided in storage tank 20 may also be used to make this determination. Alternatively, the output values ​​of both temperature sensors 15 and 25 may also be used to make this determination.

[0102] The determination in step S1 may also be made based on the amount of oxygen in decomposition tank 10. In this case, for example, a flow rate sensor may be provided at exhaust port 14 of hydrogen peroxide decomposition apparatus 3, and the value output by the flow rate sensor may be used. When the hydrogen peroxide concentration decreases and the decomposition reaction of hydrogen peroxide stops progressing, the amount of oxygen gas generated decreases. Therefore, when the value output by the flow rate sensor falls below a threshold, control unit 50 may determine that the hydrogen peroxide concentration in the liquid being treated in the final-stage hydrogen peroxide decomposition apparatus has fallen below the target concentration. Alternatively, a pressure sensor or an oxygen concentration sensor may be provided in decomposition tank 10 of hydrogen peroxide decomposition apparatus 3, and the value output by these sensors may be used.

[0103] In the above description, in step S2, the liquid supply from all circulating liquid supply units 30 is stopped simultaneously. However, this is not limited to this, and only the necessary circulating liquid supply units 30 may be stopped at each stage. That is, it is possible to stop the liquid supply from the circulating liquid supply unit 30 of the final-stage hydrogen peroxide decomposition device 3. In this case, in step S3, the liquid supply from the circulating liquid supply unit 30 of hydrogen peroxide decomposition device 2 is stopped before the liquid to be treated is sent from hydrogen peroxide decomposition device 2 to hydrogen peroxide decomposition device 3. Furthermore, the liquid supply from the circulating liquid supply unit 30 of hydrogen peroxide decomposition device 1 is stopped before the liquid to be treated is sent from hydrogen peroxide decomposition device 1 to hydrogen peroxide decomposition device 2.

[0104] Furthermore, in step S3, the circulation of the liquid to be treated by the circulating liquid feed unit 30 may be sequentially initiated for each hydrogen peroxide decomposition apparatus for which inter-apparatus liquid feed has been completed. More specifically, after the liquid to be treated has been fed from hydrogen peroxide decomposition apparatus 2 to hydrogen peroxide decomposition apparatus 3, control unit 50 may initiate liquid feed through circulating liquid feed unit 30 of hydrogen peroxide decomposition apparatus 3. Furthermore, after the liquid to be treated has been fed from hydrogen peroxide decomposition apparatus 1 to hydrogen peroxide decomposition apparatus 2, control unit 50 may initiate liquid feed through circulating liquid feed unit 30 of hydrogen peroxide decomposition apparatus 1.

[0105] In each of the above steps, when stopping the liquid transfer, the timing of stopping the pump and closing the valve may be either first or simultaneously. Preferably, the pump operation is stopped before closing the valve to avoid shut-off operation of the pump.

[0106] Similarly, when starting the liquid transfer, the valve may be opened first or the pump may be started at the same time. Preferably, the valve is opened before the pump is started to avoid shut-off operation of the pump.

[0107] <Regarding the amount of activated carbon> As described above, in each hydrogen peroxide decomposition device, the liquid to be treated is repeatedly brought into contact with activated carbon to decompose the hydrogen peroxide contained in the liquid. In this case, in the upstream hydrogen peroxide decomposition device, the liquid to be treated containing a higher concentration of hydrogen peroxide comes into contact with activated carbon 11, resulting in the generation of more reaction heat due to the decomposition reaction of hydrogen peroxide. This reaction heat further increases the rate of the decomposition reaction. Therefore, in the upstream hydrogen peroxide decomposition device, there is a risk of a sudden temperature rise due to the hydrogen peroxide decomposition reaction.

[0108] Therefore, in the hydrogen peroxide decomposition system 100 according to this embodiment, as shown in Figure 1, the amount of activated carbon 11 in the upstream hydrogen peroxide decomposition device is reduced so that the liquid to be treated circulates at a temperature below a specified value. This addresses the above problem. The specified temperature here refers to a temperature below the heat-resistant temperature of the decomposition tank 10 and storage tank 20 of the hydrogen peroxide decomposition device.

[0109] The suppression of heat generation in the upstream hydrogen peroxide decomposition device will be described below with reference to Figures 4 and 5. Figure 4 is a graph showing the relationship between hydrogen peroxide concentration and temperature rise. Figure 5 is a graph showing the relationship between activated carbon concentration and temperature rise.

[0110] As shown in Figure 4, in the decomposition reaction of hydrogen peroxide, the higher the concentration of hydrogen peroxide, the greater the temperature rise after 10 minutes. From this, it can be said that when hydrogen peroxide decomposition devices 1, 2, and 3 have the same amount of activated carbon 11, the temperature of the liquid to be treated contained in hydrogen peroxide decomposition device 1 is more likely to rise than in hydrogen peroxide decomposition devices 2 and 3. On the other hand, as shown in Figure 5, in the decomposition reaction of hydrogen peroxide, the lower the concentration of activated carbon, the smaller the temperature rise after 1 hour.

[0111] Therefore, in this embodiment, the amount of activated carbon 11 in the uppermost hydrogen peroxide decomposition device 1 is set to be less than that in the downstream hydrogen peroxide decomposition devices 2 and 3. This makes it possible to suppress temperature rise in the upstream hydrogen peroxide decomposition device 1, and allows the liquid to circulate at a temperature below a specified temperature.

[0112] In addition, since the concentration of hydrogen peroxide contained in the treated liquid circulating within the hydrogen peroxide decomposition devices 2 and 3 is lower than that in hydrogen peroxide decomposition device 1, the treated liquid can be configured to circulate at a temperature below a specified temperature without reducing the amount of activated carbon 11.

[0113] In this way, in order to suppress temperature rise in the upstream hydrogen peroxide decomposition units in hydrogen peroxide decomposition system 100, the amount of activated carbon 11 stored in the decomposition tanks 10 of the multiple hydrogen peroxide decomposition units is set to be less than the amount of activated carbon stored in at least the topmost first decomposition tank and the second decomposition tank downstream of the first decomposition tank. This allows the treated liquid in each hydrogen peroxide decomposition unit to circulate at or below a specified temperature.

[0114] A third decomposition tank may be provided between the first and second decomposition tanks. For example, in a hydrogen peroxide decomposition system 100 including hydrogen peroxide decomposition units 1, 2, and 3 as shown in Figure 1, when the amounts of activated carbon 11 stored in the decomposition tanks 10 of each hydrogen peroxide decomposition unit are designated A, B, and C from the upstream side, it is sufficient that either A < B or A < C is satisfied.

[0115] Next, the promotion of the decomposition reaction in the downstream hydrogen peroxide decomposition device will be described with reference to Figures 6 and 7. Figure 6 is a graph showing the relationship between hydrogen peroxide concentration and decomposition rate. Figure 7 is a graph showing the relationship between activated carbon concentration and decomposition rate.

[0116] As shown in Figure 6, in the decomposition reaction of hydrogen peroxide, the decomposition rate decreases as the concentration of hydrogen peroxide decreases. This causes the decomposition reaction to slow down, particularly in the final-stage hydrogen peroxide decomposition device 3. On the other hand, as shown in Figure 7, in the decomposition reaction of hydrogen peroxide, the decomposition rate increases as the amount of activated carbon 11 increases.

[0117] Therefore, in the hydrogen peroxide decomposition system 100 according to this embodiment, the decomposition rate can be maintained by increasing the amount of activated carbon 11 stored in the decomposition tank 10 of the final-stage hydrogen peroxide decomposition device 3. In the hydrogen peroxide decomposition device 3, the concentration of hydrogen peroxide contained in the liquid to be treated is low, so even if the amount of activated carbon 11 is increased, the liquid to be treated can be circulated at or below the specified temperature.

[0118] Taking into account the amount of heat generated and the decomposition rate, in hydrogen peroxide decomposition system 100, the amount of activated carbon 11 stored in decomposition tanks 10 of multiple hydrogen peroxide decomposition devices increases monotonically from the upstream hydrogen peroxide decomposition device to the downstream hydrogen peroxide decomposition device, as shown in Figure 1. For example, in hydrogen peroxide decomposition system 100 equipped with three hydrogen peroxide decomposition devices 1, 2, and 3, when the amounts of activated carbon 11 stored in decomposition tanks 10 of hydrogen peroxide decomposition devices 1, 2, and 3 are designated A, B, and C from the upstream side, the relationship A<B<C holds.

[0119] The number of hydrogen peroxide decomposition devices provided in the hydrogen peroxide decomposition system 100 may be changed depending on the concentration of hydrogen peroxide contained in the liquid to be treated stored in the liquid to be treated tank 200 and the concentration of hydrogen peroxide contained in the liquid to be treated discharged to the waste liquid tank 300 (i.e., the predetermined concentration).

[0120] For example, if the concentration of hydrogen peroxide contained in the liquid to be treated stored in the liquid to be treated tank 200 is high, it is preferable to increase the number of hydrogen peroxide decomposition devices with a small amount of activated carbon 11. This allows the liquid to be circulated at a temperature below the specified temperature in all of the hydrogen peroxide decomposition devices included in the hydrogen peroxide decomposition system 100, even when the liquid to be treated contains a higher concentration of hydrogen peroxide.

[0121] Furthermore, when the determined concentration is low, i.e., when the concentration of hydrogen peroxide contained in the liquid to be treated needs to be lowered when it is discharged into the wastewater tank 300, it is preferable to increase the number of hydrogen peroxide decomposition devices with a larger amount of activated carbon 11. This allows hydrogen peroxide to be decomposed more efficiently in hydrogen peroxide decomposition devices located further downstream.

[0122] Thus, the number of hydrogen peroxide decomposition devices included in hydrogen peroxide decomposition system 100 is not limited to three and can be any number. Preferably, the number of hydrogen peroxide decomposition devices may be 2 to 8. This allows the amount of hydrogen peroxide decomposed in each hydrogen peroxide decomposition device to be appropriate, thereby reducing the cost of the hydrogen peroxide decomposition system and efficiently decomposing the hydrogen peroxide contained in the liquid to be treated.

[0123] As described above, the hydrogen peroxide decomposition system 100 according to this embodiment can decompose hydrogen peroxide contained in the liquid to be treated and discharge effluent containing hydrogen peroxide at a predetermined concentration or less.

[0124] Furthermore, the hydrogen peroxide decomposition system 100 according to this embodiment can operate multiple hydrogen peroxide decomposition devices simultaneously, thereby enabling the hydrogen peroxide decomposition process to be carried out more efficiently even when a large amount of the liquid to be treated containing hydrogen peroxide is present.

[0125] Furthermore, hydrogen peroxide decomposition system 100 according to this embodiment is configured so that the liquid to be treated in the multiple hydrogen peroxide decomposition devices circulates at or below a specified temperature, allowing inexpensive resins such as acrylic and vinyl chloride to be used as materials for decomposition tank 10 and storage tank 20, thereby reducing the cost of the device.

[0126] Furthermore, in the hydrogen peroxide decomposition system 100 according to this embodiment, the amount of activated carbon 11 stored in the decomposition tanks 10 of the multiple hydrogen peroxide decomposition devices is such that, for at least the first decomposition tank at the top and the second decomposition tank downstream of the first decomposition tank, the amount of activated carbon stored in the first decomposition tank is less than the amount of activated carbon stored in the second decomposition tank. This allows the upstream hydrogen peroxide decomposition device to be configured to circulate the liquid to be treated at or below a specified temperature, enabling the hydrogen peroxide decomposition process to be carried out safely and efficiently.

[0127] Furthermore, in the hydrogen peroxide decomposition system 100 according to this embodiment, the amount of activated carbon 11 stored in the decomposition tanks 10 of the hydrogen peroxide decomposition devices increases monotonically from the upstream hydrogen peroxide decomposition device to the downstream hydrogen peroxide decomposition device. This promotes the decomposition reaction in the downstream hydrogen peroxide decomposition device. This also reduces the variation in the time required for the hydrogen peroxide decomposition in each hydrogen peroxide decomposition device. This allows the hydrogen peroxide decomposition process to be carried out more efficiently.

[0128] In addition, when the number of multiple hydrogen peroxide decomposition devices is three or more, the amount of activated carbon 11 may be the same in at least two or more decomposition tanks 10. Specifically, the amount of activated carbon 11 stored in the decomposition tanks 10 of the multiple hydrogen peroxide decomposition devices may be the same in each of the decomposition tanks 10 of at least two or more hydrogen peroxide decomposition devices. For example, in a hydrogen peroxide decomposition system 100 including three hydrogen peroxide decomposition devices 1, 2, and 3, when the amounts of activated carbon 11 stored in the decomposition tanks 10 of each hydrogen peroxide decomposition device 1 are designated A, B, and C from the upstream side, the relationship A<B=C may be established. This reduces the number of different amounts of activated carbon, thereby simplifying maintenance such as replenishing activated carbon 11.

[0129] In the hydrogen peroxide decomposition system according to this embodiment, spray 33 may also serve as inlet 21. For example, one end of liquid feed pipe 41 of inter-apparatus liquid feed section 40 between hydrogen peroxide decomposition apparatuses 1 and 2 is connected to outlet 22 of hydrogen peroxide decomposition apparatus 1, and the other end is connected to a location of liquid feed pipe 31 of hydrogen peroxide decomposition apparatus 2 downstream of circulation pump 32. In this case, storage tank 20 of hydrogen peroxide decomposition apparatus 2 does not need to be equipped with inlet 21.

[0130] The hydrogen peroxide decomposition apparatus according to this embodiment includes a decomposition tank 10 and a storage tank 20, and the liquid to be treated circulates between the decomposition tank 10 and the storage tank 20. This allows the hydrogen peroxide decomposition reaction to be carried out safely. For example, the decomposition reaction can be stopped simply by stopping the liquid transfer by the circulating liquid transfer unit 30. This also facilitates maintenance such as replacing and cleaning the activated carbon 11. Furthermore, by storing a certain amount of the liquid to be treated in the storage tank 20, the temperature rise due to the decomposition reaction can be slowed down, stabilizing the decomposition reaction.

[0131] Furthermore, in the hydrogen peroxide decomposition apparatus according to this embodiment, the storage tank 20 is disposed below the decomposition tank 10, and the liquid to be treated that has passed through the activated carbon 11 in the decomposition tank 10 falls freely into the storage tank 20. This simplifies the mechanism for transporting the liquid to be treated that has passed through the activated carbon 11, thereby reducing the cost of the apparatus. Furthermore, if the space between the decomposition tank 10 and the storage tank 20 is not sealed, the liquid to be treated that has passed through the activated carbon 11 can be cooled by being exposed to the outside air.

[0132] In the hydrogen peroxide decomposition apparatus according to this embodiment, the circulating liquid supply unit 30 includes a spray 33. The spray 33 breaks the liquid to be treated into fine droplets, thereby increasing the surface area of ​​the liquid that comes into contact with the activated carbon 11. This increases the efficiency of the hydrogen peroxide decomposition reaction. Furthermore, the droplets of the liquid to be treated come into contact with air, creating an air-cooling effect.

[0133] The number of sprays 33 is not limited to two as shown in FIG. 2 and may be any number. The sprays 33 may be provided with a mechanism for changing the size of the droplets sprayed, for example, by adjusting a valve (not shown) provided on the spray nozzle. This allows small droplets to be sprayed when the amount of liquid sprayed from the sprays 33 is small or when it is desired to promote the decomposition reaction. Large droplets can also be sprayed when the amount of liquid sprayed from the sprays 33 is large or when many bubbles are generated in the activated carbon 11 due to the decomposition reaction.

[0134] Furthermore, in the hydrogen peroxide decomposition apparatus according to this embodiment, the circulation / transport unit 30 includes a concentration measuring device 35 that measures the concentration of hydrogen peroxide. This allows the concentration of hydrogen peroxide in the liquid to be treated to be continuously measured, allowing the circulation to be stopped and the liquid to be transported between the devices at the appropriate times.

[0135] Furthermore, in the hydrogen peroxide decomposition apparatus according to this embodiment, the control unit 50 may perform control to perform an emergency shutdown if the temperature of the liquid being treated exceeds a temperature (dangerous temperature) that could damage the apparatus. For example, if the temperature measured by the temperature sensor exceeds the dangerous temperature, the control unit 50 may stop the liquid being sent by the circulating liquid sending unit 30. This prevents damage to the apparatus and safely stops the hydrogen peroxide decomposition reaction. The dangerous temperature may be set to the same temperature as the above-mentioned specified temperature, or may be set to a different temperature.

[0136] Furthermore, the control unit 50 may control the operation of the cooler 24 instead of or together with the circulating liquid supply unit 30. For example, when the temperature measured by the temperature sensor exceeds a dangerous temperature, the control unit 50 controls the cooler 24 to start operating. This prevents damage to the device and allows the decomposition reaction of hydrogen peroxide to be carried out safely.

[0137] Furthermore, to respond to more urgent situations, the hydrogen peroxide decomposition apparatus according to this embodiment may be equipped with a mechanism for directly discharging the liquid to be treated in storage tank 20 to the outside and / or a mechanism for introducing dilution water to stop the decomposition reaction when the temperature measured by the temperature sensor exceeds a dangerous temperature. Alternatively, hydrogen peroxide decomposition system 100 may be equipped with these mechanisms.

[0138] In the hydrogen peroxide decomposition apparatus according to this embodiment, cooler 24 may be provided outside storage tank 20. Cooler 24 may also be provided in decomposition tank 10 or in circulating liquid supply section 30. Alternatively, cooler 24 may be provided in a section between decomposition tank 10 and storage tank 20 through which the liquid to be treated passes. The operation of cooler 24 may be controlled by control section 50.

[0139] As described above, the hydrogen peroxide decomposition system 100 according to the first embodiment can efficiently decompose hydrogen peroxide contained in the liquid to be treated while suppressing the cost of the device.

[0140] Second Embodiment A hydrogen peroxide decomposition system according to a second embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing the configuration of a hydrogen peroxide decomposition system 100A according to this embodiment.

[0141] One of the differences between this embodiment and the first embodiment is the configuration of the circulating liquid transfer unit and the inter-device liquid transfer unit. The circulating liquid transfer unit 30A according to this embodiment has the function of the circulating liquid transfer unit 30 according to the first embodiment, as well as the function of the inter-device liquid transfer unit 40 according to the first embodiment. Hereinafter, the present embodiment will be described, focusing on the differences from the first embodiment, and a description of the similar parts will be omitted.

[0142] 8, circulation liquid feed section 30A of hydrogen peroxide decomposition apparatuses 1A, 2A, and 3A according to this embodiment includes liquid feed pipes 31a, 31b, and 41, circulation pump 32, valve 34, and valve 43. Circulation liquid feed is performed by liquid feed pipes 31a, 31b, circulation pump 32, and valve 34. Liquid feed between apparatuses (in the case of final-stage hydrogen peroxide decomposition apparatus 3A, discharge into waste liquid tank 300) is performed by liquid feed pipes 31a, 41, circulation pump 32, and valve 43.

[0143] The following description will be given using the circulation liquid supply section 30A of the hydrogen peroxide decomposition apparatus 1A as an example.

[0144] Liquid feed pipes 31a, 31b, and 41 are pipes for feeding the liquid to be treated to activated carbon 11 of hydrogen peroxide decomposition apparatus 1A or hydrogen peroxide decomposition apparatus 2A. More specifically, liquid feed pipes 31a, 31b, and 41 feed the liquid to be treated from outlet 22 (which also serves as circulation outlet 26) provided in storage tank 20 of hydrogen peroxide decomposition apparatus 1A to activated carbon 11 of hydrogen peroxide decomposition apparatus 1A, or to inlet 21 provided in storage tank 20 of hydrogen peroxide decomposition apparatus 2A. One end of liquid feed pipe 31a is connected to outlet 22 of hydrogen peroxide decomposition apparatus 1A, and the other end is connected to one end of liquid feed pipe 31b and one end of liquid feed pipe 41. The other end of liquid feed pipe 31b is located above decomposition tank 10A of hydrogen peroxide decomposition apparatus 1A. The other end of liquid feed pipe 41 is connected to inlet 21 of hydrogen peroxide decomposition apparatus 2A.

[0145] The circulation pump 32 is provided in the liquid feed pipe 31 a and feeds the liquid to be treated through the liquid feed pipes 31 a , 31 b , and 41 .

[0146] Valve 34 is provided in liquid feed pipe 31b, and valve 43 is provided in liquid feed pipe 41. Valves 34 and 43 switch whether the liquid to be treated discharged from circulation pump 32 is fed from outlet 22 of hydrogen peroxide decomposition apparatus 1A to activated carbon 11 of hydrogen peroxide decomposition apparatus 1A, or from outlet 22 of hydrogen peroxide decomposition apparatus 1A to hydrogen peroxide decomposition apparatus 2A.

[0147] Specifically, the circulating liquid sending unit 30A functions as a circulating liquid sending unit by opening the valve 34 and closing the valve 43. On the other hand, the circulating liquid sending unit 30A functions as an inter-device liquid sending unit by closing the valve 34 and opening the valve 43.

[0148] The valves 34 and 43 are examples of a switching unit, and the configuration of the switching unit is not limited to that described above. For example, instead of the valves 34 and 43, a three-way valve may be provided at the portion where the liquid supply pipe 31a branches into the liquid supply pipe 31b and the liquid supply pipe 41.

[0149] The same applies to circulation supply unit 30A of hydrogen peroxide decomposition apparatus 2A. Furthermore, circulation supply unit 30A of hydrogen peroxide decomposition apparatus 3A is similar to circulation supply unit 30A of hydrogen peroxide decomposition apparatuses 1A and 2A, except that the liquid to be treated is discharged to wastewater tank 300 instead of being sent to the next hydrogen peroxide decomposition apparatus.

[0150] As described above, the hydrogen peroxide decomposition system 100A and hydrogen peroxide decomposition devices 1A, 2A, and 3A according to the second embodiment can reduce the number of pumps and further reduce the cost of the device compared to the first embodiment.

[0151] In this embodiment, circulating liquid supply unit 30A of hydrogen peroxide decomposition apparatus 1A also serves as the inter-apparatus liquid supply unit between hydrogen peroxide decomposition apparatuses 1A and 2A. This is not limiting, and circulating liquid supply unit 30A of hydrogen peroxide decomposition apparatus 2A may also serve as the inter-apparatus liquid supply unit between hydrogen peroxide decomposition apparatuses 1A and 2A. In this case, the switching unit may switch between supplying the liquid to be treated from circulation outlet 26 of hydrogen peroxide decomposition apparatus 2A to activated carbon 11 of hydrogen peroxide decomposition apparatus 2A, or from outlet 22 of hydrogen peroxide decomposition apparatus 1A to inlet 21 of hydrogen peroxide decomposition apparatus 2A.

[0152] Third Embodiment A hydrogen peroxide decomposition system according to a third embodiment will be described with reference to Figure 9. Figure 9 is a diagram showing the configuration of a hydrogen peroxide decomposition system 100B according to this embodiment. One of the differences between this embodiment and the first embodiment is the configuration for circulating the liquid to be treated at a temperature below a specified temperature. Hereinafter, this embodiment will be described, focusing on the differences from the first embodiment, and a description of similar parts will be omitted.

[0153] In this embodiment, the amount of the liquid to be treated circulated by the circulation liquid supply section (hereinafter also referred to as the "circulation amount") is configured to be less than the amount circulated by the upstream hydrogen peroxide decomposition device compared to the amount circulated by the downstream hydrogen peroxide decomposition device, so that the liquid to be treated circulates at a temperature below a specified temperature.

[0154] Specifically, for hydrogen peroxide decomposition system 100B including hydrogen peroxide decomposition devices 1B, 2B, and 3B in FIG. 9 , when the amounts of the liquid to be treated delivered by circulation delivery units 30 of each hydrogen peroxide decomposition device are A, B, and C from the upstream side, either A<B or A<C holds. More specifically, for the multiple hydrogen peroxide decomposition devices, the amount of the liquid to be treated delivered by the circulation delivery units is less than the amount of the liquid to be treated delivered by the second circulation delivery unit, at least for the topmost first circulation delivery unit and the second circulation delivery unit downstream of the first circulation delivery unit. Note that a third circulation delivery unit may be provided between the first and second circulation delivery units. Furthermore, in this embodiment, A<B<C holds.

[0155] In this case, any method can be used to reduce the circulation volume. For example, the circulation pump 30 of the upstream hydrogen peroxide decomposition apparatus may deliver a small amount of the liquid to be treated, or may deliver the liquid intermittently. Specifically, the operating speed (discharge rate) of the circulation pump 32 may be changed. Alternatively, as shown in FIG. 9 , a valve 36 may be provided downstream of the circulation pump 32, and the amount of the liquid to be treated delivered by the circulation pump 30 may be adjusted by adjusting the opening of the valve 36. Furthermore, a temperature sensor may be provided so that the delivery of the liquid is stopped when the temperature exceeds a specified temperature and resumed when the temperature falls below the specified temperature.

[0156] In hydrogen peroxide decomposition system 100B according to this embodiment, it is preferable that at least one of the multiple hydrogen peroxide decomposition devices 1B, 2B, and 3B is equipped with cooler 24. Furthermore, it is preferable that a hydrogen peroxide decomposition device located further upstream is equipped with cooler 24. This is because the temperature of the upstream hydrogen peroxide decomposition device is more likely to rise as the liquid to be treated, which contains a high concentration of hydrogen peroxide, passes through activated carbon 11.

[0157] In this embodiment, the amount of activated carbon in each of the hydrogen peroxide decomposition devices 1B, 2B, and 3B may be the same, or the amount of activated carbon in the downstream hydrogen peroxide decomposition device may be greater than the amount of activated carbon in the upstream hydrogen peroxide decomposition device.

[0158] In the hydrogen peroxide decomposition system 100B of this embodiment, the circulation rate can be changed between the hydrogen peroxide decomposition devices, allowing the liquid to be circulated at or below a specified temperature. This simplifies maintenance because it is not necessary to change the amount of activated carbon 11 for each hydrogen peroxide decomposition device.

[0159] According to the hydrogen peroxide decomposition systems 100, 100A, and 100B of the first to third embodiments described above, it is possible to efficiently decompose hydrogen peroxide contained in the liquid to be treated while suppressing the cost of the device.

[0160] In each of the above embodiments, the hydrogen peroxide decomposition devices in the hydrogen peroxide decomposition system are not limited to being connected in a daisy chain as shown in Figure 1, but may be branched into two or more branches at intermediate hydrogen peroxide decomposition devices. For example, for each hydrogen peroxide decomposition device, there may be two or more hydrogen peroxide decomposition devices located in the next stage.

[0161] In each of the above embodiments, the circulation of the liquid to be treated is not limited to being carried out within each hydrogen peroxide decomposition device, but may be carried out across a plurality of hydrogen peroxide decomposition devices.

[0162] Alternatively, one hydrogen peroxide decomposition device may be placed at a higher location, and the next hydrogen peroxide decomposition device may be placed at a lower location, thereby replacing the inter-device pump 42 of the inter-device liquid transfer section 40. In other words, the inter-device liquid transfer may be performed by gravity.

[0163] In each of the above embodiments, the pumps, valves, sensors, etc. are automatically controlled by the control unit 50. However, this is not limiting, and at least one of the pumps, valves, sensors, etc. may be manually controlled. When the inter-device liquid transfer is manually controlled, the concentration measuring device 35 may not be provided.

[0164] In addition, in each of the above embodiments, the temperature sensor and the float sensor output values ​​to the control unit 50, but this is not limited to this. The sensor scale may be photographed by an imaging unit such as a camera connected to the control unit 50, and the control unit 50 may read the value of each sensor by analyzing the photographed image. Alternatively, the liquid level of the liquid to be treated stored in the storage tank 20 may be photographed, and the height of the liquid level may be read by image analysis.

[0165] Based on the above description, a person skilled in the art may conceive additional effects and various modifications of the present invention, but the aspects of the present invention are not limited to the individual embodiments described above. Elements from different embodiments may be combined as appropriate. Various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and spirit of the present invention, which is derived from the content defined in the claims and their equivalents.

[0166] DESCRIPTION OF SYMBOLS 1, 2, 3, 1A, 2A, 3A, 1B, 2B, 3B Hydrogen peroxide decomposition apparatus 10 Decomposition tank 11 Activated carbon 12 Filter 13 Support section 14 Exhaust port 15, 25 Temperature sensor 20 Storage tank 21 Inlet 22 Outlet 23 Float sensor 24 Cooler 26 Circulation outlet 30, 30A Circulation liquid transfer section 31, 31a, 31b Liquid transfer pipe 32 Circulation pump 33 Spray 34, 36 Valve 35 Concentration measuring device 40 Inter-device liquid transfer section 41 Liquid transfer pipe 42 Inter-device pump 43 Valve 50 Control section 100, 100A, 100B Hydrogen peroxide decomposition system 200 Tank for liquid to be treated 300 Drain tank

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