Method for regenerating active carbon

Abstract

To regenerate used powder active carbon by microwave heating, and recover / improve adsorptivity.SOLUTION: A method for regenerating active carbon includes the steps of: mounting active carbon having an average particle diameter of 1 to 100 μm on a flat plate; and regenerating the active carbon on the flat plate by microwave heating. The flat plate may be repeatedly moved forward / backward by a belt conveyor or a roller conveyor during the microwave heating. The temperature of the active carbon during the microwave heating may be measured, and microwave irradiation energy may be controlled on the basis of the measurement result.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a regeneration method and a regeneration system for recovering the adsorption performance of used activated carbon by desorbing and separating substances adsorbed on the activated carbon from the activated carbon using microwave heating. [Background technology]

[0002] The types of regeneration furnaces that are widely used to regenerate activated carbon include multi-furnace regeneration furnaces for large furnaces with 4 to 8 stacked cylindrical furnace chambers, rotary kiln regeneration furnaces for medium-sized furnaces, and direct current superheating regeneration furnaces for small furnaces that are heated by passing electricity through electrodes. Currently, all regeneration furnaces in Japan are external heating furnaces that use fossil fuels such as heavy oil and gas as heat resources. When regenerating activated carbon by external heating, heat is transmitted to the inside by thermal conduction, which has low thermal conductivity and is inefficient for heating objects with large volumes, and requires a long heating time.

[0003] In addition, conventional heating furnace activated carbon regeneration equipment has a limit to the particle size that can be regenerated, and when regenerating powdered products finer than 40 mesh (0.56 mm), especially powdered activated carbon with a particle size distribution of 1 to 100 μm, problems due to scattering of dust occur, so it has not been applied to practical equipment. Therefore, granular activated carbon with a large particle size can be reused by recovering it after adsorption and regenerating it by heating in a regeneration furnace, while powdered activated carbon with a small particle size is recovered as a solid-liquid separation product or dehydrated cake by filtration after using a new product, and disposed of as industrial waste. Alternatively, used powdered activated carbon was collected for use as livestock feed or soil fertilizer, and was diverted to low-added-value applications.

[0004] In recent years, research into microwave heating recycling, which allows for a shift to non-fossil energy, has been progressing with the growing need to achieve carbon neutrality by 2050 and the spread of the idea of ​​a carbon circular economy. In the regeneration method using microwave heating, the microwave electric field penetrates the target object to be heated and is converted into thermal energy from the inside, so internal heating can be achieved in a short time without the need for thermal conduction.

[0005] However, when scaling up microwave heating to an actual plant, there were problems with insufficient measures to prevent uneven heating and low recovery performance values ​​of regenerated activated carbon.

[0006] Patent Document 1 describes a method for regenerating activated carbon using microwave heating, in which used activated carbon is stored in a cylindrical heating container with an empty space greater than the volume of the used activated carbon, allowing microwaves to be uniformly incident on the activated carbon.

[0007] Patent Document 2 describes a regeneration method in which hot water is blown in to remove the carbonized organic matter desorbed from used activated carbon regenerated by microwave heating, and the volume expansion as the water turns into steam provides a blowing-out removal effect.

[0008] Furthermore, Patent Document 3 describes a method in which activated carbon is placed in a circulation path, the activated carbon is heated by microwaves to desorb the adsorbates from the activated carbon, thereby regenerating the activated carbon, and a mixed gas of an inert gas circulating in the circulation path and the desorbed adsorbate gas is cooled and condensed to separate and recover the adsorbates. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2001-89120 A [Patent Document 2] JP 2001-89121 A [Patent Document 3] Japanese Patent Application Publication No. 6-31163 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in consideration of the above-mentioned conventional situation, and an object of the present invention is to provide a regeneration method and a regeneration system that can regenerate used powdered activated carbon by microwave heating and restore and improve its adsorption performance. [Means for solving the problem]

[0011] [1] A step of placing activated carbon having an average particle size of 1 to 100 μm on a flat plate; regenerating the activated carbon on the plate by microwave heating; The method for regenerating activated carbon comprises the steps of:

[0012] [2] The method for regenerating activated carbon described in [1], wherein the plate is repeatedly moved forward and backward using a belt conveyor or roller conveyor while microwave heating is being performed.

[0013] [3] A method for regenerating activated carbon described in [1], comprising measuring the temperature of the activated carbon during microwave heating and controlling microwave irradiation energy based on the measurement result.

[0014] [4] The method for regenerating activated carbon described in [1], wherein the activated carbon is heated by microwaves in a heating treatment box having an oxygen concentration of 2% or less.

[0015] [5] The method for regenerating activated carbon described in [4], further comprising treating exhaust gas from the heat treatment box and supplying the treated gas to the heat treatment box.

[0016] [6] A method for regenerating activated carbon described in [1], in which the height of the activated carbon on the flat plate is made uniform using a scraping plate before microwave heating is performed.

[0017] [7] A hopper for supplying activated carbon having an average particle size of 1 to 100 μm onto a flat plate; A leveling plate for adjusting the height of the activated carbon on the flat plate to a constant level; a conveying unit that conveys the plate on which the activated carbon is placed to a heat treatment box; A microwave generator that irradiates microwaves into the heat treatment box; An activated carbon regeneration system comprising:

[0018] [8] The activated carbon regeneration system described in [7], wherein the conveying section has a belt conveyor or a roller conveyor, and repeatedly moves the flat plate on which the activated carbon is placed forward and backward within the heating treatment box during microwave irradiation. Effect of the Invention

[0019] According to the present invention, used powdered activated carbon can be regenerated by microwave heating, and its adsorption performance can be restored and improved. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic configuration diagram of an activated carbon regeneration system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a functional block diagram of a control device. [Diagram 3] 1 is a graph showing an example of a change in microwave irradiation energy during activated carbon regeneration treatment. [Figure 4] 1 is a graph showing an example of temperature change during activated carbon regeneration treatment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment will be described with reference to the drawings.

[0022] The activated carbon regeneration system according to the embodiment of the present invention shown in FIG. 1 irradiates used activated carbon with microwaves to heat and regenerate it, and is particularly suitable for regenerating powdered activated carbon with a small particle size.

[0023] Used activated carbon 1 to be regenerated is supplied from a hopper 2 onto a plate 3. The activated carbon 1 is powdered activated carbon with an average particle size of 1 to 100 μm. The average particle size of the powdered activated carbon is the median diameter D 50Alternatively, it may be an average particle diameter as determined by observation with a scanning transmission electron microscope. There is no particular limitation on the used activated carbon 1 to be regenerated. For example, the iodine adsorption capacity is 50 to 1800 mg / g, the specific surface area is 300 to 2000 m 2 / g.

[0024] The plate 3 is made of quartz or a metal such as SUS, and is, for example, a flat plate having a rectangular shape when viewed from above. The dimensions of the plate 3 are not particularly limited. A substantially rectangular frame is provided on one main surface (front surface) of the plate 3, and the activated carbon 1 supplied from the hopper 2 is spread inside the frame.

[0025] The plate 3 on which the activated carbon 1 is placed is transported to a heat treatment box 6 by a transport unit 4. The transport unit 4 is, for example, a belt conveyor or a roller conveyor.

[0026] A leveling plate 5 is provided near the hopper 2, and as the plate 5 moves, the height of the activated carbon 1 laid out within the frame becomes constant.

[0027] When the plate 3 is transported into the heat treatment box 6, the microwave leakage prevention shutter 11 closes, making the inside of the box an airtight space. A microwave generator 7 is connected to the heat treatment box 6. Microwaves generated by the microwave generator 7 are guided into the heat treatment box 6 to heat the activated carbon 1 (and plate 3). The microwaves are irradiated from multiple points on the top of the heat treatment box 6. A microwave source with a frequency of 2.45 GHz and a maximum output of about 24 kW is used. An example of a microwave source is a microwave oven.

[0028] The control device 20 controls the microwave irradiation energy. The control method will be described later.

[0029] The heat treatment box 6 may be provided with a sensor (not shown) that measures the reflected energy of the microwaves. Also, a meter using the principle of a differential thermometer that can measure the carbonization and carbon dioxide conversion of the adsorbed substance may be installed.

[0030] A propeller 9 that evenly reflects microwaves may be installed inside the heat treatment box 6. The propeller 9 is made of a metal such as SUS. The number of blades of the propeller 9 is not limited and may be, for example, about 2 to 5. A plurality of propellers 9 may be installed.

[0031] During microwave irradiation, the plate 3 may be moved back and forth (repeatedly forward and backward) in the heat treatment box 6 by the conveying section 4 at a slow speed that does not scatter the powdered activated carbon, thereby suppressing uneven heating.

[0032] Exhaust gas generated by heating the activated carbon 1 is discharged by a blower (not shown) from an exhaust pipe 8 connected to the heat treatment box 6. The exhaust gas discharged from the exhaust pipe 8 is measured for TOC (total organic carbon) and wet concentration by a gas analyzer (not shown). In addition, the exhaust pipe 8 is provided with a gas flowmeter (not shown) for measuring the ventilation flow rate of the blower.

[0033] A supply pipe (not shown) for supplying nitrogen gas, superheated steam or carbon dioxide gas is connected to the heat treatment box 6. The exhaust gas discharged from the exhaust pipe 8 is treated using a known exhaust gas treatment method such as a scrubber treatment or a plasma treatment. Since the treated gas has a low oxygen concentration, it is preferable to return it to the heat treatment box 6 again. By maintaining a low oxygen concentration inside the heat treatment box 6 (for example, 0.2% or less), it is possible to suppress the carbon component from being discharged outside the system as carbon dioxide, and improve the recovery rate of the regenerated product.

[0034] An infrared camera 10 for measuring the temperature of the activated carbon 1 on the plate 3 is installed in the heat treatment box 6. A thermal conduction type thermometer for measuring the temperature of the activated carbon 1 may also be provided.

[0035] When the regeneration process of the activated carbon 1 is completed, the microwave leakage prevention shutter 11 opens, and the plate 3 is carried out from the heat treatment box 6. The regenerated activated carbon 1 is recovered from the plate 3.

[0036] The control device 20 is a computer having a CPU and memory, and as shown in Figure 2, has the functions of a temperature acquisition unit 21, an exhaust gas component acquisition unit 22, a flow rate acquisition unit 23, a reflected energy amount acquisition unit 24, and a microwave irradiation energy control unit 25.

[0037] The temperature acquisition unit 21 acquires the temperature of the activated carbon 1 during the regeneration process from the infrared camera 10 or the like.

[0038] The exhaust gas component acquisition unit 22 acquires analysis results of the TOC and wet concentration of the exhaust gas from the gas analyzer.

[0039] The flow rate acquisition unit 23 acquires the measurement result of the ventilation flow rate of the blower from the gas flow meter.

[0040] The reflected energy amount acquiring unit 24 acquires the measurement result of the reflected energy amount of the microwave. The consumed energy amount of the microwave is calculated from the difference between the irradiated energy amount and the reflected energy amount.

[0041] The activated carbon regeneration method according to this embodiment includes a drying process for removing moisture from used activated carbon, a calcination / desorption process for calcining and desorbing the substance (adsorbed substance) adsorbed by the activated carbon, a reactivation process for gasifying the remaining carbonized adsorbed substance, and a cooling process for cooling the activated carbon.

[0042] The microwave irradiation energy control unit 25 judges the state of the activated carbon 1 based on the temperature of the activated carbon 1, the exhaust gas components, etc., determines which process to execute from the drying process, the firing / desorption process, the reactivation process, and the cooling process, and outputs a control signal to the microwave generator 7 so that the irradiation energy is appropriate for the process.

[0043] FIG. 3 shows an example of the change in microwave irradiation energy during the regeneration process, and FIG. 4 shows an example of the change in temperature of the powdered activated carbon 1 during the regeneration process.

[0044] After purging the heating treatment box 6 with nitrogen, microwave irradiation is started to perform the drying process (period T1 in Fig. 3 and Fig. 4). In the drying process, the temperature of the activated carbon rises due to microwave irradiation, and the initial moisture evaporates, so that the temperature becomes constant at around 100°C.

[0045] When the moisture contained in the activated carbon evaporates and the drying step is completed, the temperature rises rapidly to 100°C or higher. The microwave irradiation energy is reduced to maintain the regeneration temperature at a predetermined temperature, and the calcination / desorption step is performed (period T2 in Figs. 3 and 4). The predetermined regeneration temperature in the calcination / desorption step is an optimum temperature according to the amount of the adsorbed substance and the carbonization rate. For example, the calcination / desorption step is performed at a temperature range of 200 to 1400°C, preferably 500 to 1200°C.

[0046] In the initial stage of the calcination / desorption step, microwave energy is used for the desorption reaction of the adsorbed substances. In the latter half of the calcination / desorption step (period T2) when the desorption of the adsorbed substances has progressed to a certain extent, the irradiation energy is adjusted to be somewhat lower and the temperature of the activated carbon is maintained constant. For example, the irradiation energy in the latter half of the calcination / desorption step is adjusted to about 80 to 95% of the irradiation energy in the first half.

[0047] When it is determined from the analysis results of the exhaust gas that the components of the adsorbed substances in the exhaust gas are below a predetermined value and the firing / desorption process is completed, the irradiation energy is increased to raise the regeneration temperature and a reactivation process is performed (period T3 in Figs. 3 and 4). The completion of the firing / desorption process may be determined by monitoring the carbonization removal status based on differential thermal measurements and the amount of microwave energy consumption. In the reactivation process, the adsorbed substances remaining and carbonized in the firing / desorption process are gasified by contacting them with superheated steam, carbon dioxide gas, or an oxidizing gas such as oxygen (water-gasification reaction) and discharged from the exhaust pipe 8. For example, the irradiation energy in the reactivation process is set to be slightly higher than that in the firing / desorption process and lower than that in the drying process.

[0048] It is known that the upper limit for determining the temperature and residence time of the reactivation conditions can be determined based on the gasification loss of the activated carbon itself, and the higher the temperature, the shorter the residence time can be exponentially.

[0049] When it is determined from the analysis of the exhaust gas that the components of the adsorbed substances in the exhaust gas are below a predetermined value and the reactivation process is completed, the microwave irradiation is stopped and a cooling process is carried out (period T4 in Figures 3 and 4) to cool the activated carbon to below 100°C. To avoid a sudden drop in temperature, the temperature is gradually lowered by ventilating with a blower in a nitrogen purged atmosphere or a low-oxygen atmosphere of 2% or less. Ventilation may be performed by circulating the exhaust gas after scrubber treatment.

[0050] By such a regeneration process, the adsorption performance of used powdered activated carbon can be restored to the same level as that of new powdered activated carbon. Moreover, by subjecting new powdered activated carbon to the same process, the adsorption performance can be further improved.

[0051] In this embodiment, the powdered activated carbon to be regenerated is placed on the plate 3, leveled to a certain thickness, and then irradiated with microwaves, which can suppress ignition and uneven heating due to scattering of fine powder. In addition, the temperature of the activated carbon on the plate 3 and the exhaust gas components during the regeneration process are monitored by instruments to control the microwave irradiation energy, which can improve the quality of the regenerated product. By making it possible to regenerate powdered carbon, it can be reused as regenerated powdered carbon, which has high added value in food processing, making it possible to reduce costs compared to using new coal.

[0052] In the conventional activated carbon regeneration process using heat transfer from external heat, in addition to heating the used activated carbon, heat loss occurs due to heating of the heating furnace device itself and heat transfer to the surroundings. However, in the microwave irradiation according to this embodiment, the activated carbon 1 is directly heated and heat transfer is mainly to the plate 3 in contact with the activated carbon 1, so that efficient thermal regeneration can be performed. Therefore, it is expected that the amount of CO2 generated converted from the electricity consumption by microwave heating will be significantly reduced compared to the amount of CO2 generated converted from fossil energy such as gas and heavy oil by the conventional external heating method.

[0053] Heat regeneration by microwave irradiation enables conversion to non-fossil energy, and depending on the type of electricity used, carbon neutrality is possible. In addition, the amount of CO2 generated can be reduced by recycling used activated carbon, and secondarily, the carbon footprint of customers' manufactured products can be reduced.

[0054] Conventionally, the regeneration control temperature was managed to be uniform and versatile within the temperature range of 800 to 850°C. However, in this embodiment, the optimal regeneration temperature can be set based on differential thermal measurement and desorption end point prediction, and regeneration is possible even at 500 to 600°C, which makes it possible to conserve thermal energy.

[0055] In the above embodiment, the used powdered activated carbon to be regenerated may be powdered activated carbon alone, or may be mixed with a filter material used in precoat filtration for the decolorization process or other target adsorption treatment processes, such as diatomaceous earth powder. It is desirable to sufficiently reduce the moisture content of the mixture of powdered activated carbon and powdered diatomaceous earth. The moisture content is preferably 80% or less, and more preferably 50% or less.

[0056] The activated carbon regeneration system according to the above embodiment can regenerate powdered activated carbon with an average particle size of 1 to 100 μm, but can also be applied to the regeneration of crushed or pellet-type granular activated carbon with a particle size of 100 μm or more (100 μm to 10 mm). It is possible to switch to non-fossil energy in the regeneration of various types of used activated carbon without being limited by particle size, and it is possible to significantly reduce the amount of CO2 generated.

[0057] The activated carbon regeneration system according to the above embodiment has been described as being configured to suppress uneven heating by moving the plate 3 carrying the powdered activated carbon 1 back and forth on a conveyor belt or the like within the heat treatment box 6. However, the plate 3 may also be rotated on a turntable.

[0058] The adsorbent to be regenerated is not limited to carbon-based adsorbents including activated carbon and activated carbon fiber materials, but may be zeolite, silica gel, alumina, and the like. EXAMPLES

[0059] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0060] Example 1 As a sample of used adsorbent, a mixture of powdered activated carbon (average particle size 37 μm) after adsorption of organic matter and diatomaceous earth powder (average particle size 24 μm) after filtration treatment in a weight ratio of 9:1 (water content 40%) was prepared. The iodine adsorption performance of this sample before regeneration was 170 mg / g. A rectangular frame (outer dimensions 100 mm x 100 mm x 20 mm, width dimension 10 mm) was placed on a quartz flat plate (130 mm x 130 mm x 10 mm), and 50.31 g of sample was spread evenly inside the frame and placed on a turntable in a microwave irradiation box (400 mm x 400 mm x 400 mm).

[0061] The microwave irradiation box was purged with nitrogen at a flow rate of 10 L / min for 5 minutes, after which microwave heating regeneration was started. Microwaves were irradiated while rotating the turntable at 7 rpm. The blower flow rate for discharging the desorbed gas outside the system was 4.5 m 3 The microwave irradiation energy was changed in the following order: 1000W for 180 seconds, 500W for 660 seconds, 700W for 180 seconds, 900W for 300 seconds, and 1000W for 180 seconds.

[0062] At the blower outlet, which discharges gas from the microwave irradiation box to the outside of the system, the smell of water vapor and desorbed components was confirmed when the temperature reached 100°C. When the temperature reached 600°C, white smoke was emitted from the desorbed gas along with a burnt odor. The temperature was then maintained until the white smoke subsided, and then the burnt odor gradually disappeared. The test was terminated when the odor had sufficiently subsided. When the white smoke first began to be emitted, it is believed that not only the vaporization of the adsorbed material but also the carbonization of the desorbed components had begun. Later, when the odor disappeared, it is believed that almost all of the adsorbed material had been desorbed from the used activated carbon and diatomaceous earth.

[0063] The sample after heat regeneration was collected and its weight and iodine adsorption capacity were measured. The measurement results are shown in Table 1. It was confirmed that the iodine adsorption capacity was restored to 580 mg / g.

[0064] Example 2 The sample was spread in the frame with 70.01 g, and the microwave irradiation energy was changed in sequence from 1000 W for 780 seconds, to 1200 W for 120 seconds, to 1400 W for 900 seconds. The thermal regeneration of Example 2 was carried out in the same manner as in Example 1. The measurement results are shown in Table 1. It was confirmed that the iodine adsorption performance was restored to 580 mg / g.

[0065] Example 3 A square frame (outer dimensions 200mm x 200mm x 20mm, width 10mm) was placed on a SUS plate measuring 380mm x 380mm x 2mm, and 1205g of sample was placed inside the frame. In order to avoid local heating at the four corners, the sample was moved inward so that a 30mm square circle was formed. The SUS plate on which the sample was placed was fixed to the center of the bottom of a microwave irradiation box (length 700mm, width 1500mm, height 1200mm) which was a belt conveyor type. To ensure uniform microwave irradiation, propellers (70mm x 150mm x 4 pieces) installed at a 45 degree angle at two points on the top were rotated at 7rpm. The blower flow rate for discharging the desorbed gas was 7.5m / s. 3 / min. The microwave irradiation energy was changed to 2000 W for 1800 seconds, 1000 W for 420 seconds, 2000 W for 300 seconds, and 2500 W for 780 seconds. The test was completed when the odor of the exhaust gas was sufficiently eliminated.

[0066] The sample after heat regeneration was collected and its weight and iodine adsorption capacity were measured. The measurement results are shown in Table 1. It was confirmed that the iodine adsorption capacity was restored to 530 mg / g.

[0067] Example 4 The sample was spread in the frame of 1200 g, and the corners were moved inward to form a circle of 30 mm square to avoid local heating. The microwave irradiation energy was changed to 2000 W for 1740 seconds, 1000 W for 420 seconds, 3500 W for 240 seconds, and 4500 W for 900 seconds. The thermal regeneration of Example 4 was carried out in the same manner as in Example 3. The measurement results are shown in Table 1. It was confirmed that the iodine adsorption performance was restored to 600 mg / g.

[0068] Example 5 Granular activated carbon (average particle size 37 μm, moisture content 10%, iodine adsorption capacity before regeneration 790 mg / g) that had adsorbed the same organic matter as the powdered activated carbon contained in the sample of Example 1 was used as the sample. 50.73 g of the sample was spread inside the frame, and the thermal regeneration of Example 5 was carried out in the same manner as in Example 1, except that the microwave irradiation energy was changed to 1000 W for 150 seconds and 500 W for 900 seconds.

[0069] The sample after heat regeneration was collected and its weight and iodine adsorption capacity were measured. The measurement results are shown in Table 1. It was confirmed that the iodine adsorption capacity was restored to 900 mg / g.

[0070] Example 6 Microwave heating in Example 6 was carried out in the same manner as in Example 1, except that the sample was new powdered activated carbon (average particle size 34 μm). The heated sample was collected and the weight and iodine adsorption performance were measured. The measurement results are shown in Table 1. The iodine adsorption performance was 1000 mg / g for firewood charcoal, but improved to 1070 mg / g after heating. This is thought to be due to further development of micropores by microwave heating.

[0071] Comparative Example 1 A cylindrical rotating drum (φ200 mm, height 100 mm) simulating a rotary kiln type heating furnace was installed in a microwave irradiation box (400 mm × 400 mm × 400 mm) at an angle of 45 ° C. 390.49 g of the same sample as in Example 1 was placed in this rotating drum. After nitrogen purging was performed for 5 minutes at a flow rate of 10 L / min in the microwave irradiation box, microwave heating regeneration was started while rotating the rotating drum at a rotation speed of 3 rpm.

[0072] The microwave irradiation energy was changed in sequence from 2000W for 660 seconds, 1000W for 60 seconds, and 1200W for 210 seconds, and the temperature inside the rotating drum was maintained at approximately 500 to 600°C.

[0073] In this regeneration test, powder scattered along with the desorbed gas from the mixture of used activated carbon and diatomaceous earth, and the powdered carbon adhered to the inside of the microwave irradiation box, resulting in a scattered deposition. After thermal regeneration, the samples were collected and their weight and iodine adsorption performance were measured. The measurement results are shown in Table 2. Although the iodine adsorption performance recovered to 530 mg / g, it was confirmed that it is not realistic to put the effects of the fine powder scattered along with the desorbed gas coming out of the rotating drum into practical use.

[0074] Comparative Example 2 A microwave heating test of Comparative Example 2 was carried out in the same manner as in Example 1, except that the sample was a 40 g mixture of the diatomaceous earth used in the precoat filtration and the substance to be filtered (organic substance), and microwaves were irradiated at a constant irradiation energy of 1000 W. The test was stopped because the sample ignited 470 seconds after the start of irradiation.

[0075] Comparative Example 3 A microwave heating test of Comparative Example 3 was carried out in the same manner as in Example 1, except that the irradiation energy was changed to 500 W after irradiation with microwaves at 1000 W for 150 seconds. The test was discontinued because the sample ignited 200 seconds after the irradiation energy was changed to 500 W.

[0076] [Table 1]

[0077] [Table 2]

[0078] The present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0079] 1 activated carbon 2. Hopper 3 boards 4. Conveyor 5. Sliding board 6 Heat Treatment Box 7. Microwave Generator 8. Exhaust pipe 9 Propeller 10. Infrared Camera 11 Microwave leakage prevention shutter 20 Control device

Claims

1. A step of placing activated carbon having an average particle size of 1 to 100 μm on a flat plate; a drying step in which the inside of the heat treatment box is purged with nitrogen, and then microwave irradiation is started, and the microwave irradiation is continued until the initial moisture in the activated carbon evaporates and the temperature becomes constant at about 100° C.; When the temperature rises to 100°C or higher, the microwave irradiation energy is reduced and maintained at 200 to 1400°C in a firing / desorption process; a reactivation step in which, when the amount of the adsorbed substance in the exhaust gas is equal to or less than a predetermined value based on the analysis result of the exhaust gas, the microwave irradiation energy is increased more than that in the firing / desorption step to raise the regeneration temperature, and the microwave irradiation is continued until the amount of the adsorbed substance in the exhaust gas is equal to or less than the predetermined value; The method for regenerating activated carbon comprises the steps of:

2. 2. The method for regenerating activated carbon according to claim 1, wherein the flat plate is advanced and / or retreated within the heat treatment box by a belt conveyor or a roller conveyor during microwave heating.

3. The method for regenerating activated carbon according to claim 1 , further comprising measuring a temperature of the activated carbon during microwave heating, and controlling microwave irradiation energy based on the measurement result.

4. 2. The method for regenerating activated carbon according to claim 1, wherein the activated carbon is heated by microwaves in a heat treatment box having an oxygen concentration of 2% or less.

5. 5. The method for regenerating activated carbon according to claim 4, further comprising treating the exhaust gas from the heat treatment box and supplying the treated gas to the heat treatment box.

6. 2. The method for regenerating activated carbon according to claim 1, further comprising the step of: making the height of the activated carbon on the plate constant using a scraping plate; and then carrying out microwave heating.

Images