Method for regenerating adsorbents and apparatus for regenerating adsorbents

Abstract

This invention provides a method for regenerating an adsorbent that allows for easy control of the detachment of organofluorine compounds from the adsorbent to which the organofluorine compounds are attached. [Solution] A method for regenerating an adsorbent, comprising a contact step of bringing an adsorbent to which an organic fluorine compound is attached into contact with steam heated to 150°C or higher to remove the organic fluorine compound from the adsorbent.

Description

Technical Field

[0001] The present disclosure relates to, for example, a method for regenerating an adsorbent and a device for regenerating an adsorbent.

Background Art

[0002] Adsorbents such as activated carbon are used in adsorption processes in fields such as wastewater treatment, exhaust gas treatment, or deodorization treatment. The adsorbent used in the adsorption process has a reduced adsorption capacity. In order to reuse the adsorbent, it is necessary to restore the adsorption capacity. For this reason, as a method for regenerating the adsorbent from the used adsorbent, for example, a method of maintaining the inside of a regeneration furnace containing used activated carbon at 800°C or higher, and a method of bringing steam heated to a high temperature into contact with the used activated carbon (see, for example, Patent Documents 1 to 2) are known.

[0003] Adsorbents used in adsorption processes such as aqueous solutions containing organic fluorine compounds are usually discarded as industrial waste without undergoing a regeneration process. Some organic fluorine compounds are classified as hardly decomposable substances. Such organic fluorine compounds may exist in water, soil, or the atmospheric environment without being decomposed for many years.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional methods for regenerating adsorbents from used adsorbents that have adsorbed ordinary organic compounds include, for example, regeneration furnaces using external heating with heavy oil or gas. These regeneration furnaces are operated in a temperature range of approximately 800°C to 900°C. When adsorbents with attached organofluorine compounds are directly introduced into a regeneration furnace in the above temperature range, various organofluorine compounds are desorbed from the adsorbent at once, making it difficult to control the atmospheric diffusion or decomposition treatment of the organofluorine compounds.

[0006] The present disclosure aims to provide a method for regenerating an adsorbent that makes it easier to control the detachment of organofluorine compounds from the adsorbent to which the organofluorine compounds are attached. [Means for solving the problem]

[0007] One embodiment of the method for regenerating an adsorbent according to the present disclosure includes a contact step of bringing an adsorbent to which an organofluorine compound is attached into contact with steam heated to 150°C or higher to remove the organofluorine compound from the adsorbent. [Effects of the Invention]

[0008] This disclosure provides a method for regenerating an adsorbent to which the organofluorine compound is attached, making it easier to control the desorption of the organofluorine compound from the adsorbent. For example, the desorption of the organofluorine compound from the adsorbent can be controlled by controlling the temperature of the water vapor that comes into contact with the adsorbent. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram schematically showing one embodiment of the regeneration device of the present disclosure. [Figure 2] Figure 2 is a block diagram schematically showing one embodiment of the purification treatment apparatus of the present disclosure. [Modes for carrying out the invention]

[0010] In this specification, the numerical range N1 to N2 means N1 or greater and N2 or less. In this specification, if the units of the numbers before and after the "~" indicating a numerical range are the same, the unit of the number before the "~" may be omitted.

[0011] [Method for regenerating adsorbent] The method for regenerating an adsorbent according to this disclosure includes a contact step of removing the organofluorine compound from the adsorbent by bringing the adsorbent to which the organofluorine compound is attached into contact with steam heated to preferably 150°C or higher.

[0012] In this specification, "removing the target substance from the adsorbent" means removing at least a portion of the target substance from the adsorbent. "Removal" includes not only the desorption of the target substance from the adsorbent but also its decomposition. "Desorption" means that the target substance separates from the adsorbent by volatilization or other means. The target substance is, for example, an organofluorine compound.

[0013] By using the regeneration method of this disclosure, adsorbents can be regenerated. In this specification, "regeneration of adsorbents" means at least partially restoring the adsorption capacity of an adsorbent, or enhancing its adsorption capacity, by removing organofluorine compounds attached to the adsorbent. Furthermore, by using the regeneration method of this disclosure, adsorbents with restored adsorption capacity can be produced.

[0014] Hereinafter, "adsorbent to which organofluorine compounds are attached" will also be referred to as "adsorbent (A)". Adsorbent (A) comprises an adsorbent and an organofluorine compound adhering to the adsorbent by adsorption or other means. Adsorbent (A) may contain one or more adsorbents. Adsorbent (A) may contain one or more organofluorine compounds. Adsorbent (A) is, for example, a used adsorbent.

[0015] Examples of adsorbents include activated carbon such as powdered activated carbon and granular activated carbon, zeolite, silica gel, activated alumina, and ion exchange resins. Among these, activated carbon is preferred. Granular activated carbon has a larger particle size than powdered activated carbon.

[0016] Examples of organofluorine compounds include perfluoroalkyl compounds having a perfluoroalkyl group and polyfluoroalkyl compounds having a polyfluoroalkyl group.

[0017] Examples of perfluoroalkyl compounds include perfluoroalkyl sulfonic acid and its derivatives, perfluoroalkyl carboxylic acid and its derivatives, perfluoroalkyl ethers such as perfluoro(2-butyl-tetrahydrofuran), perfluoroalkanes, perfluoroalkyl sulfides, perfluoroalkyl iodides, perfluoroalkylamines such as perfluorotributylamine, perfluoroalkyl phosphate esters, perfluoroalkylsilane compounds, and salts thereof.

[0018] Examples of polyfluoroalkyl compounds include polyfluoroalkyl sulfonic acids and their derivatives, polyfluoroalkyl carboxylic acids and their derivatives, polyfluoroalkyl ethers, polyfluoroalkanes, polyfluoroalkyl sulfides, polyfluoroalkyl iodides, polyfluoroalkylamines, polyfluoroalkyl phosphate esters, polyfluoroalkylsilane compounds, and salts thereof.

[0019] Specific examples of the organic fluorine compound include perfluorobutanesulfonic acid, perfluoro(2-ethoxyethane)sulfonic acid, perfluoropentanesulfonic acid, perfluoro-1,3-propanedisulfonic acid, 1H,1H,2H,2H-perfluorohexanesulfonic acid, perfluorohexanesulfonic acid (PFHxS), perfluoroheptanesulfonic acid, 1H,1H,2H,2H-perfluorooctanesulfonic acid, 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, perfluorooctanesulfonic acid (PFOS), perfluorooctanesulfonic acid fluoride, perfluorooctanesulfonic acid amide, perfluorononanesulfonic acid, 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, 1H,1H,2H,2H-perfluorodecanesulfonic acid, perfluorodecanesulfonic acid, N-ethylperfluorooctanesulfonamidoacetic acid, N-methylperfluorooctanesulfonamidoacetic acid, perfluoroundecanesulfonic acid, perfluorododecanesulfonic acid, perfluorotridecanesulfonic acid, perfluoropropionic acid, perfluorobutyric acid, perfluoro-3-methoxypropionic acid, nonafluoro-3,6-dioxaheptanoic acid, perfluoro-4-methoxybutyric acid, perfluoropentanoic acid, hexafluoropropylene oxide dimer acid, perfluorohexanoic acid, 4,8-dioxa-3H-perfluorononanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid (PFOA), perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorobutane, perfluoropentane, perfluorohexane, perfluorooctane, perfluorodecane, perfluorododecane, perfluorotetradecane, perfluorohexadecane, perfluorobutylethyl sulfide, perfluorohexylethyl sulfide, perfluorooctylethyl sulfide, perfluorooctyl iodide, and perfluorodecyl iodide.

[0020] Among organic fluorine compounds, at least one selected from the group consisting of perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), and perfluorooctanoic acid (PFOA) is preferred, and at least one selected from the group consisting of perfluorohexanesulfonic acid (PFHxS) and perfluorooctanoic acid (PFOA) is more preferred.

[0021] Examples of the above derivatives include esters, amides, and halides. Examples of the above salts include alkali metal salts such as lithium salts, sodium salts, and potassium salts; amine salts such as alkanolamine salts such as monoethanolamine salts, diethanolamine salts, and triethanolamine salts; and ammonium salts.

[0022] The number of carbon atoms of the organic fluorine compound is preferably 20 or less, more preferably 18 or less, still more preferably 16 or less, and particularly preferably 14 or less. The boiling point of the organic fluorine compound at 1 atm is preferably 120 to 800 °C, more preferably 120 to 500 °C, still more preferably 120 to 400 °C, and particularly preferably 120 to 300 °C.

[0023] The adsorbent (A) may contain two or more organic fluorine compounds having different boiling points.

[0024] <Contact step> In the contact step, the adsorbent (A) is brought into contact with heated water vapor (heated steam) to remove the organic fluorine compound from the adsorbent (A). By this step, the organic fluorine compound can be removed from the adsorbent (A) by desorption, decomposition, etc., and the adsorbent can be regenerated.

[0025] The heated steam in the contact step functions as a heat source for removing the organofluorine compound from the adsorbent (A). The temperature of the heated steam in the contact step is preferably 150°C or higher and can be appropriately determined according to the boiling point or vapor pressure of the organofluorine compound to be removed from the adsorbent (A). For example, the temperature of the heated steam may be 200°C or higher, 250°C or higher, 300°C or higher, 350°C or higher, 400°C or higher, 450°C or higher, or 500°C or higher.

[0026] The temperature of the heated steam in the contact process is preferably 1200°C or lower, more preferably 1100°C or lower, even more preferably 1000°C or lower, and particularly preferably 900°C or lower, for example, 150 to 1200°C, from the viewpoint of suppressing deterioration of the adsorbent itself (e.g., changes in pore properties).

[0027] The amount of heated steam supplied to contact the adsorbent (A) in the contact process is preferably 0.1 to 60 vol.%, more preferably 1 to 40 vol.%, and even more preferably 2 to 20 vol.%.

[0028] Since the regeneration method described herein can use heated steam with a low oxygen gas content, the contact process can be carried out in an atmosphere close to an oxygen-free state. Therefore, such a regeneration method can suppress the deterioration of the quality of the adsorbent itself.

[0029] In the contact step, it is preferable to supply water vapor to an adsorbent container containing the adsorbent (A) to bring the adsorbent (A) into contact with the water vapor. Therefore, it is preferable that the above regeneration method further includes a preparation step of preparing the adsorbent container by putting the adsorbent (A) into the container. The gas discharged from the adsorbent container includes, for example, water vapor and gaseous organofluorine compounds that have been desorbed from the adsorbent by heating.

[0030] In the contact process, steam heated to 150°C or higher may be supplied to the adsorbent container, or steam may be supplied to the adsorbent container and the steam may be heated to 150°C or higher within the adsorbent container. In the latter case, the adsorbent container is equipped with a heating section.

[0031] If moisture is attached to the adsorbent (if adsorbent (A) contains moisture), the moisture attached to the adsorbent will volatilize by bringing heated steam into contact with the adsorbent (A). In the contact step, it is preferable to bring steam heated to 100°C or higher but less than 150°C into contact with the adsorbent (A), and then bring steam heated to 150°C or higher into contact with the adsorbent (A). In this configuration, the organic fluorine compounds can be removed after the moisture attached to the adsorbent has been volatilized and removed. For example, by primarily volatilizing the moisture attached to the adsorbent first and then removing the organic fluorine compounds, it is possible to achieve efficient energy use and uniform heating.

[0032] The desorption temperature at which organofluorine compounds are released from the adsorbent varies depending, for example, on the volatility of the organofluorine compound and the interaction between the organofluorine compound and the adsorbent. Above the desorption temperature, the organofluorine compound attached to the adsorbent is released as a desorbed gas along with water vapor.

[0033] Generally, differences in the volatility of compounds are largely influenced by their molecular weight. Compounds with smaller molecular weights tend to have lower boiling points, higher volatility, and are less likely to be adsorbed by adsorbents such as activated carbon. Compounds with larger molecular weights tend to have higher boiling points, lower volatility, and are more easily adsorbed by adsorbents. For example, in adsorption to activated carbon, compounds with 6 or more carbon atoms are easily adsorbed, and the amount of adsorption tends to decrease as the number of carbon atoms decreases to 5 or less.

[0034] When the adsorbent (A) contains two or more organic fluorine compounds with different boiling points or volatilities (when two or more organic fluorine compounds with different boiling points adhere to the adsorbent), in the contact step, by gradually or stepwise increasing the temperature of the heated steam brought into contact with the adsorbent (A), for example, the organic fluorine compounds can be selectively removed from the adsorbent (A) according to the boiling point or volatility of the organic fluorine compounds by separating them by the temperature of the heated steam. The organic fluorine compounds desorbed from the adsorbent are removed as gas components (desorbed gases) together with the steam, and the organic fluorine compounds can be simply separated by type using the differences in boiling point or volatility and the temperature of the heated steam. Specifically, the organic fluorine compounds can be removed from the adsorbent (A) in the order from the organic fluorine compound with higher volatility to the organic fluorine compound with lower volatility, or in the order from the organic fluorine compound with lower boiling point to the organic fluorine compound with higher boiling point. The above "in order" does not only mean that the removal of the organic fluorine compound with higher boiling point starts after the removal of the organic fluorine compound with lower boiling point is completed, but also includes that the peak of the removal amount (desorption amount) of the organic fluorine compound with lower boiling point is located on the lower temperature side than that of the organic fluorine compound with higher boiling point.

[0035] For example, the case where a first organic fluorine compound having a boiling point T1 and a second organic fluorine compound having a boiling point T2 adhere to the adsorbent will be described. Here, T1 (°C) < T2 (°C). In this case, in the contact step, after bringing the steam heated in a low temperature range (for example, a range of T1 or higher and lower than T2) into contact with the adsorbent (A), the steam heated in a high temperature range (for example, a range of T2 or higher) may be brought into contact with the adsorbent (A). Thereby, the organic fluorine compounds can be desorbed from the adsorbent in the order of the first organic fluorine compound and the second organic fluorine compound.

[0036] The emission concentration standards may vary depending on the type of organic fluorine compound. According to the above regeneration method, by adjusting the temperature, heating rate, supply rate, etc. of the heated steam brought into contact with the adsorbent (A), it becomes easier to control the desorption rate of the organic fluorine compound from the adsorbent (A) and the concentration of the organic fluorine compound in the desorbed gas.

[0037] <Incineration Process> The regeneration method of this disclosure may further include an incineration step of incinerating the gas obtained in the contact step (gas discharged from the adsorbent container). The gas is, for example, a mixed gas containing water vapor and gaseous organofluorine compounds desorbed from the adsorbent by heating. The organofluorine compounds contained in the gas can be decomposed by the incineration process. The incineration temperature of the gas in the incineration process is preferably 1000°C or higher, more preferably 1000 to 1500°C, and even more preferably 1000 to 1300°C. The incineration time (residence time) of the gas in the incineration process is preferably 2 seconds or higher, more preferably 3 seconds to 20 minutes, and even more preferably 5 seconds to 10 minutes. The gas after incineration may be cooled and liquefied.

[0038] <Liquefaction process> The regeneration method disclosed herein, after the contact step, A liquefaction step is performed in which the mixed gas containing the water vapor supplied in the above contact step and the organofluorine compound desorbed from the adsorbent is cooled to form an aqueous solution in which the organofluorine compound desorbed from the adsorbent is dissolved in the condensed water of the water vapor. It is preferable to further have the following:

[0039] The mixed gas containing water vapor and an organofluorine compound is cooled (including cooling by heat dissipation) to liquefy the water vapor. For example, the mixed gas can be introduced into a liquefaction device such as a condenser, and the water vapor can be cooled and liquefied to obtain the aqueous solution. This suppresses the diffusion of the organofluorine compound detached from the adsorbent into the atmosphere.

[0040] The cooling temperature is not particularly limited, but is preferably less than 100°C, more preferably 80°C or lower, even more preferably 60°C or lower, even more preferably 40°C or lower, and especially preferably 30°C or lower.

[0041] The aqueous solution obtained in this manner can be treated as wastewater according to conventionally known methods. Methods for treating the wastewater include, for example, activated carbon adsorption treatment as described in Appleman, TD, Dickenson, ERV, Bellona, ​​C. and Higgins, CP (2013) Nanofiltration and granular activated carbon treatment of perfluoroalkyl acids. Journal of Hazardous Materials, 260, 740-746., ion exchange treatment as described in Du, Z., Deng, S., Bei, Y., Huang, Q., Wang, B., Huang, J., Yu, G., Adsorption behavior and mechanism of perfluorinated compounds on various adsorbents-a review. J.Hazard. Mat. 274 (2014) 443-454., and Kucharzyk, KH; Darlington, R.; Benotti, M.; Deeb, R.; Hawley, E. Novel treatment technologies for PFAS compounds: A critical review. J. Environ. Manag. 2017, 204. Examples include the RO film treatment method described in 757-764.

[0042] [Adsorbent regeneration device] The adsorbent regeneration apparatus of the present disclosure, An adsorbent container containing an adsorbent (adsorbent (A)) to which an organofluorine compound is attached, A steam generator that produces steam, A steam supply line connecting the above-mentioned steam generator and the above-mentioned adsorbent container, A gas discharge line through which the gas discharged from the above adsorbent container flows, It is equipped with. The above-described regeneration device includes a heating section capable of adjusting the steam temperature to preferably 150°C or higher, located in one or more places selected from the group consisting of a steam generator, a steam supply line, and an adsorbent container.

[0043] The adsorbent container contains the adsorbent (A). The adsorbent container has, for example, a layer of the adsorbent (A) (hereinafter also referred to as the "adsorbent layer"). The adsorbent layer may be, for example, a stationary layer or a fluidized layer. The material used to construct the adsorbent container is not particularly limited, but examples include steel materials such as stainless steel (SUS).

[0044] The adsorbent container includes, for example, a water vapor inlet and a gas outlet. The location of the steam inlet in the adsorbent container is not particularly limited. The steam inlet may be located, for example, within the adsorbent layer in the adsorbent container, or it may be located above or below the adsorbent layer in the direction of gravity. The steam inlet may be located, for example, at the top (or apex) or bottom (or base) of the adsorbent container. The steam supply line is connected to the steam inlet. The location of the gas outlet in the adsorbent container is not particularly limited. The gas outlet may be located, for example, below or above the adsorbent layer in the direction of gravity. The gas outlet may be located, for example, at the bottom (or base) or top (or apex) of the adsorbent container. The gas outlet line is connected to the gas outlet.

[0045] The adsorbent container may be configured in an upward flow manner, for example, by introducing water vapor from the bottom (or base) of the container and removing the gas from the top (or top), or in a downward flow manner, by introducing water vapor from the top (or top) of the container and removing the gas from the bottom (or base).

[0046] Examples of heating devices for heating steam include direct heating devices such as cartridge heaters, flange heaters, infrared heaters, tape heaters, and ceramic heaters; and indirect heating devices such as induction heaters, dielectric heaters, and microwave heaters. The temperature of the steam heated in the heating device is the same as the temperature range described in the <Contact Process> section. The above regeneration device may further include a temperature sensor for measuring the temperature of the water vapor.

[0047] The adsorbent container may be equipped with the heating unit described above. This heating unit heats the steam introduced into the adsorbent container. When the steam is heated in the adsorbent container and brought into contact with the adsorbent (A), it is not necessary to preheat the steam in the steam supply line to, for example, 150°C or higher, and it is not necessary to provide a heating unit for heating the steam on the steam supply line.

[0048] A steam generator is a device that generates steam. The steam generator may include the heating section described above. The heating unit described above may be provided on the steam supply line. This heating unit heats the steam flowing through the steam supply line. The heating unit can be installed anywhere on the steam supply line as long as it can heat the steam, but it is preferable to install it in a location close to the adsorbent container in order to minimize heat loss from the steam.

[0049] The steam supply line connects the steam generator and the adsorbent container. The steam supply line may be equipped with at least one selected from the group consisting of a pressure regulating valve, a flow meter, and a pressure sensor. The pressure regulating valve is a valve that adjusts the supply pressure of steam supplied from the steam generator to the adsorbent container. The flow meter is a device that measures the flow rate of steam circulating in the steam supply line. The flow meter may be electrically connected to the control device. The control device acquires steam flow rate information based on the measurement value of the flow meter. The pressure sensor is a device that measures the supply pressure of steam. The pressure sensor may be electrically connected to the control device. The control device acquires pressure information based on the measurement value of the pressure sensor.

[0050] In the gas discharge line, the gas discharged from the adsorbent container flows. This gas is, for example, water vapor that has come into contact with the adsorbent, or a mixed gas containing water vapor that has come into contact with the adsorbent and an organofluorine compound that has been desorbed from the adsorbent. Each line is composed of, for example, piping.

[0051] The regeneration apparatus of this disclosure may further include an incineration apparatus for incinerating the gas discharged from the adsorbent container. Examples of incineration apparatuses include known burner combustion apparatuses. In this case, the gas discharge line connects the adsorbent container and the incineration apparatus.

[0052] The regeneration apparatus of this disclosure may further include a liquefaction device for liquefying the gas discharged from the adsorbent container. The liquefaction device is not particularly limited as long as it can liquefy water vapor, and examples include conventionally known condensing devices. In this case, the gas discharge line connects the adsorbent container and the liquefaction device.

[0053] [Methods for purifying fluids] The fluid purification method of this disclosure comprises a step of bringing a fluid containing an organofluorine compound into contact with an adsorbent to cause the organofluorine compound to adhere to the adsorbent (hereinafter also referred to as the "adsorption step"), and a step of regenerating the adsorbent by the regeneration method of this disclosure described above (hereinafter also referred to as the "regeneration step").

[0054] The fluid containing organofluorine compounds that is subject to purification treatment will also be referred to as the "fluid to be treated" below. Examples of fluids include liquids and gases. Examples of liquids include aqueous solutions containing organofluorine compounds (e.g., drinking water, wastewater, effluent, and groundwater). Examples of gases include gases containing organofluorine compounds (e.g., exhaust gas from incineration facilities, etc.). Details of the organofluorine compounds and adsorbents are as described above. The details of the regeneration process are as described above.

[0055] According to the purification method of this disclosure, it is possible to purify fluids containing organofluorine compounds and to regenerate adsorbents whose adsorption capacity has decreased as a result of this purification treatment.

[0056] [Fluid purification treatment device] The regeneration device of this disclosure may be incorporated into a fluid purification device for purifying fluids containing organofluorine compounds. The purification device also functions as an adsorbent regeneration device.

[0057] The fluid purification apparatus of this disclosure is An adsorbent container containing an adsorbent, A fluid supply line for supplying a fluid containing an organofluorine compound to the adsorbent container, A fluid discharge line through which the treated fluid discharged from the above adsorbent container flows, A steam generator that produces steam, A steam supply line connecting the above-mentioned steam generator and the above-mentioned adsorbent container, A gas discharge line through which the gas discharged from the above adsorbent container flows, It is equipped with. The above-mentioned purification apparatus is equipped with a heating unit capable of adjusting the temperature of the steam to preferably 150°C or higher, in one or more locations selected from the group consisting of a steam generator, a steam supply line, and an adsorbent container. The above-mentioned purification treatment apparatus may further include an incineration apparatus for incinerating the gas discharged from the adsorbent container. The above-mentioned purification treatment apparatus may further include a liquefaction apparatus for liquefying the gas discharged from the adsorbent container.

[0058] The adsorbent container, steam generator, steam supply line, gas discharge line, heating unit, incineration treatment device, and liquefaction device are as described above, and a detailed explanation is omitted in this section.

[0059] The above-described purification apparatus may further include a storage container for the fluid containing the organofluorine compound (fluid to be treated). The fluid supply line connects the storage container and the adsorbent container.

[0060] The adsorbent container holds the adsorbent. The adsorbent container includes, in addition to a steam inlet and a gas outlet, a fluid inlet for introducing the fluid to be treated and a fluid outlet for discharging the fluid after purification. The fluid supply line is connected to the fluid inlet. The fluid discharge line is connected to the fluid discharge outlet.

[0061] The adsorbent container may be configured in an upward flow manner, for example, by introducing the fluid to be treated from the bottom (or base) of the container and removing the purified fluid from the top (or top), or in a downward flow manner, by introducing the fluid to be treated from the top (or top) of the container and removing the purified fluid from the bottom (or base). The direction of water vapor flow in the adsorbent container may be the same as or different from the direction of flow of the fluid to be treated in the adsorbent container. The water vapor inlet may be a dedicated inlet or may be shared with the fluid inlet. The gas outlet may be a dedicated outlet or may be shared with the fluid outlet.

[0062] The regeneration apparatus and purification apparatus of this disclosure will be described below with reference to the drawings. The regeneration device 1 shown in Figure 1 comprises an adsorbent container 10, a steam generator 20, a liquefaction device 30, a steam supply line L1 connecting the steam generator 20 and the adsorbent container 10, and a gas discharge line L2 connecting the adsorbent container 10 and the liquefaction device 30. A heating unit 40 is provided on the steam supply line L1. The adsorbent container 10 includes a steam inlet 12 and a gas outlet 14. The steam supply line L1 is connected to the steam inlet 12. The gas outlet line L2 is connected to the gas outlet 14.

[0063] The purification treatment apparatus 2 shown in Figure 2 comprises the regeneration apparatus 1, a storage container 50 for the fluid to be treated, a fluid supply line L3 connecting the storage container 50 and the adsorbent container 10, and a fluid discharge line L4 through which the purified fluid discharged from the adsorbent container 10 flows. The adsorbent container 10 further includes a fluid inlet 16 and a fluid outlet 18. The fluid supply line L3 is connected to the fluid inlet 16. The fluid outlet line L4 is connected to the fluid outlet 18.

[0064] The following describes the flow of the fluid to be treated during fluid purification and the flow of water vapor during adsorbent regeneration, using the purification treatment apparatus 2 shown in Figure 2. Adsorbent regeneration is not performed during fluid purification, and fluid purification is not performed during adsorbent regeneration. A third on-off valve V3 is provided in the fluid supply line L3. A first on-off valve V1 is provided in the steam supply line L1. A fourth on-off valve V4 is provided in the fluid discharge line L4. A second on / off valve V2 is provided in the gas discharge line L2.

[0065] During the fluid purification process, the third on-off valve V3 and the fourth on-off valve V4 are open, and the first on-off valve V1 and the second on-off valve V2 are closed. In this state, the fluid to be treated is supplied to the adsorbent container 10 through the fluid supply line L3, and the fluid comes into contact with the adsorbent, causing organic fluorine compounds and other substances contained in the fluid to be adsorbed by the adsorbent, thereby purifying the fluid. The purified fluid to be treated is then transported to the desired location through the fluid discharge line L4.

[0066] During the regeneration process of the adsorbent, the third on-off valve V3 and the fourth on-off valve V4 are closed, and the first on-off valve V1 and the second on-off valve V2 are open. In this state, water vapor, which is the regeneration medium for the adsorbent, is supplied into the adsorbent container 10 through the water vapor supply line L1. The water vapor comes into contact with the adsorbent, removing organic fluorine compounds and other substances that have adhered to the adsorbent, and the adsorbent is regenerated. The gas discharged from the gas outlet 14 contains water vapor and organic fluorine compounds. This mixed gas is supplied to the liquefaction device 30 through the gas discharge line L2 and subjected to liquefaction treatment.

[0067] In the above-described purification treatment apparatus 2, the adsorbent, whose adsorption capacity has decreased, can be regenerated using water vapor without having to remove it from the apparatus. Therefore, the above-described purification treatment apparatus 2 can reduce costs such as labor costs, transportation costs, and regeneration costs.

[0068] Although the regeneration apparatus and purification apparatus of this disclosure have been described above based on the above embodiments with reference to the attached drawings, the regeneration apparatus and purification apparatus of this disclosure are not limited to the above embodiments and various modifications are possible. For example, in Figure 2, a steam supply line L1 is connected to a fluid supply line L3, and a single three-way valve is provided at this connection point instead of the first and third on-off valves, and the steam inlet 12 and the fluid inlet 16 are a single shared inlet. A gas discharge line L2 is connected to a fluid discharge line L4, and a single three-way valve is provided at this connection point instead of the second and fourth on-off valves, and the gas outlet 14 and the fluid outlet 18 are a single shared outlet.

[0069] [Example of behavior] This disclosure relates, for example, to the following [1] to

[13] . [1] A method for regenerating an adsorbent, comprising a contact step of bringing an adsorbent to which an organofluorine compound is attached into contact with steam heated to 150°C or higher to remove the organofluorine compound from the adsorbent. [2] The method for regenerating an adsorbent according to [1], wherein the contact step includes supplying steam heated to 150°C or higher to an adsorbent container containing the adsorbent, thereby bringing the adsorbent into contact with the steam. [3] The method for regenerating an adsorbent according to [2], further comprising a preparation step of preparing the adsorbent container by putting the adsorbent into a container. [4] A method for regenerating an adsorbent according to any one of the above [1] to [3], wherein the contact step includes bringing steam heated to 100°C or more and less than 150°C into contact with the adsorbent, and then bringing steam heated to 150°C or more into contact with the adsorbent. [5] A method for regenerating an adsorbent according to any one of the above [1] to [4], wherein two or more organofluorine compounds with different boiling points are attached to the adsorbent, and the contact step includes removing the organofluorine compounds from the adsorbent in order from the organofluorine compounds with lower boiling points to the organofluorine compounds with higher boiling points by increasing the temperature of the water vapor that comes into contact with the adsorbent. [6] A method for regenerating an adsorbent according to any one of the above [1] to [5], further comprising a liquefaction step after the contact step, in which a mixed gas containing the water vapor supplied in the contact step and the organofluorine compound desorbed from the adsorbent is cooled to form an aqueous solution in which the organofluorine compound desorbed from the adsorbent is dissolved in the condensed water of the water vapor. [7] A method for regenerating an adsorbent according to any one of the above [1] to [6], wherein the adsorbent is activated carbon. [8] A method for producing an adsorbent, comprising the step of producing an adsorbent using the method for regenerating an adsorbent described in any one of the above items [1] to [7]. [9] A method for purifying a fluid, comprising the steps of: bringing a fluid containing an organofluorine compound into contact with an adsorbent to cause the organofluorine compound to adhere to the adsorbent; and regenerating the adsorbent by the method for regenerating an adsorbent described in any one of the above [1] to [7].

[10] An adsorbent regeneration device comprising: an adsorbent container containing an adsorbent to which an organofluorine compound is attached; a steam generator for generating steam; a steam supply line connecting the steam generator and the adsorbent container; and a gas discharge line through which gas discharged from the adsorbent container flows, wherein a heating unit capable of adjusting the temperature of the steam to 150°C or higher is provided at one or more locations selected from the group consisting of the steam generator, the steam supply line and the adsorbent container.

[11] The adsorbent regeneration apparatus according to

[10] , wherein the regeneration apparatus further comprises a liquefaction apparatus for liquefying the gas discharged from the adsorbent container, and the gas discharge line connects the adsorbent container and the liquefaction apparatus.

[12] A fluid purification apparatus comprising: an adsorbent container containing an adsorbent; a fluid supply line for supplying a fluid containing an organofluorine compound to the adsorbent container; a fluid discharge line through which the purified fluid discharged from the adsorbent container flows; a steam generator for generating steam; a steam supply line connecting the steam generator and the adsorbent container; and a gas discharge line through which the gas discharged from the adsorbent container flows, wherein a heating unit capable of adjusting the temperature of the steam to 150°C or higher is provided at one or more locations selected from the group consisting of the steam generator, the steam supply line and the adsorbent container.

[13] The fluid purification apparatus according to

[12] , wherein the purification apparatus further comprises a liquefaction device for liquefying the gas discharged from the adsorbent container, and the gas discharge line connects the adsorbent container and the liquefaction device. [Examples]

[0070] A method for regenerating the adsorbent described herein will be explained based on a test example. However, the above regeneration method is not limited in any way to the following test examples.

[0071] [Example Test] Perfluorooctanoic acid (PFOA, boiling point: 188°C) and perfluorohexanesulfonic acid (PFHxS, boiling point: 238°C) were pre-adsorbed onto 10-35 mesh granular activated carbon (FILTRASORB 400, manufactured by Kuraray Co., Ltd.). An adsorbent container was prepared by filling a Φ16mm × 100mm SUS test column with the pre-adsorbed activated carbon. Subsequently, the adsorbent container was placed in a heated steam supply line, and heated steam was supplied to the adsorbent container at a flow rate of 10 L / h for 30 minutes.

[0072] The superheated steam temperature was 110°C, 150°C, 210°C, 500°C, or 800°C. In some test examples, the superheated steam temperature was set higher than the boiling point of at least one of PFOA or PFHxS.

[0073] After the test was completed, the activated carbon was removed from the adsorbent container after it had cooled sufficiently, and a sample was obtained. Using the sample, the organofluorine compounds remaining on the activated carbon were extracted, and the extracted organofluorine compounds were identified by gas chromatography-mass spectrometry (GC-MS). The results are shown in Table 1.

[0074] [Table 1]

[0075] As the temperature of the water vapor increased, desorption from the activated carbon began in order from compounds with lower boiling points to those with higher boiling points (PFOA, PFHxS), resulting in the production of desorbed gases. [Explanation of Symbols]

[0076] 1...Playback device 2. Purification treatment equipment 10…Adsorbent container 12... Steam inlet 14…Gas outlet 16… Fluid inlet 18...Fluid outlet 20...Steam generator 30...Liquefaction device 40...Heating part 50…Storage container for the fluid to be processed L1...Water vapor supply line L2…Gas discharge line L3…Fluid supply line L4…Fluid discharge line V1~V4...1st to 4th on / off valves

Claims

1. A method for regenerating an adsorbent, comprising a contact step of bringing an adsorbent to which an organofluorine compound is attached into contact with steam heated to 150°C or higher to remove the organofluorine compound from the adsorbent.

2. The method for regenerating an adsorbent according to claim 1, wherein the contact step includes supplying steam heated to 150°C or higher to an adsorbent container containing the adsorbent, thereby bringing the adsorbent into contact with the steam.

3. The method for regenerating an adsorbent according to claim 2, further comprising a preparation step of preparing the adsorbent container by putting the adsorbent into a container.

4. The method for regenerating an adsorbent according to claim 1, wherein the contact step includes bringing steam heated to 100°C or more and less than 150°C into contact with the adsorbent, and then bringing steam heated to 150°C or more into contact with the adsorbent.

5. The adsorbent has two or more organofluorine compounds with different boiling points attached to it. The contact step includes increasing the temperature of the water vapor that comes into contact with the adsorbent, thereby removing the organofluorine compounds from the adsorbent in order from those with lower boiling points to those with higher boiling points. A method for regenerating an adsorbent according to claim 1.

6. After the contact step, A liquefaction step in which the mixed gas containing the water vapor supplied in the contact step and the organofluorine compound desorbed from the adsorbent is cooled to form an aqueous solution in which the organofluorine compound desorbed from the adsorbent is dissolved in the condensed water of the water vapor. A method for regenerating an adsorbent according to claim 1, further comprising the above.

7. The method for regenerating an adsorbent according to any one of claims 1 to 6, wherein the adsorbent is activated carbon.

8. A method for producing an adsorbent, comprising the step of producing an adsorbent using a method for regenerating an adsorbent according to any one of claims 1 to 6.

9. A step of bringing a fluid containing an organofluorine compound into contact with an adsorbent to cause the organofluorine compound to adhere to the adsorbent, A step of regenerating the adsorbent by the method for regenerating the adsorbent described in any one of claims 1 to 6, A method for purifying a fluid, comprising [a specific characteristic].

10. An adsorbent container containing an adsorbent to which an organofluorine compound is attached, A steam generator that produces steam, A steam supply line connecting the steam generator and the adsorbent container, A gas discharge line through which the gas discharged from the adsorbent container flows, Equipped with, A heating unit capable of adjusting the temperature of the steam to 150°C or higher is provided in one or more locations selected from the group consisting of the steam generator, the steam supply line, and the adsorbent container. A regeneration device for adsorbents.

11. The adsorbent regeneration apparatus according to claim 10, wherein the regeneration apparatus further comprises a liquefaction apparatus for liquefying the gas discharged from the adsorbent container, and the gas discharge line connects the adsorbent container and the liquefaction apparatus.

12. An adsorbent container containing an adsorbent, A fluid supply line that supplies a fluid containing an organofluorine compound to the adsorbent container, A fluid discharge line through which the treated fluid discharged from the adsorbent container flows, A steam generator that produces steam, A steam supply line connecting the steam generator and the adsorbent container, A gas discharge line through which the gas discharged from the adsorbent container flows, Equipped with, A heating unit capable of adjusting the temperature of the steam to 150°C or higher is provided in one or more locations selected from the group consisting of the steam generator, the steam supply line, and the adsorbent container. Fluid purification treatment device.

13. The fluid purification apparatus according to claim 12, wherein the purification apparatus further comprises a liquefaction device for liquefying the gas discharged from the adsorbent container, and the gas discharge line connects the adsorbent container and the liquefaction device.

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