A microwave regeneration device and method for waste granular activated carbon

Abstract

The application discloses a microwave regeneration device and method for waste granular activated carbon, which comprises a shell, a plurality of microwave generators, a plurality of temperature sensors, a gas distributor, a stirrer and a controller, wherein the plurality of microwave generators are arranged in a ring shape on the shell, and the radiation surface formed is substantially perpendicular to the running direction of the waste granular activated carbon; the plurality of temperature sensors are uniformly arranged on the inner wall of the shell; the gas distributor is arranged around the waste granular activated carbon, and gas nozzles are uniformly distributed on the gas distributor and arranged towards the inside; the microwave generators and the temperature sensors are connected with the controller; and the stirrer is provided with a plurality of layers of stirring blades.

Description

Technical Field

[0001] This invention belongs to the field of activated carbon regeneration technology, specifically relating to a microwave regeneration device and method for waste granular activated carbon. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Granular activated carbon, with its unique and well-developed pore structure and large specific surface area, plays a crucial role in many fields such as wastewater treatment, air purification, and food processing. In wastewater treatment, it can adsorb heavy metal ions, organic pollutants, and other harmful substances, enabling the wastewater to be purified and discharged in compliance with standards. In air purification, it can effectively remove harmful gases such as formaldehyde and benzene, as well as odors, improving indoor and outdoor air quality. In food processing, it can adsorb impurities and odors, ensuring the pure taste and quality safety of food.

[0004] However, activated carbon gradually becomes saturated with use, and discarding saturated activated carbon directly can have serious consequences. From a resource perspective, the production of activated carbon requires a large amount of raw materials such as wood and coal, as well as energy; indiscriminate disposal is a huge waste of resources. From an environmental perspective, if large quantities of discarded activated carbon enter the natural environment, the pollutants it adsorbs may be released again, polluting soil, water bodies, and the atmosphere, and disrupting the ecological balance.

[0005] Therefore, activated carbon regeneration technology has become an inevitable choice. Traditional thermal regeneration methods require prolonged heating at high temperatures, such as maintaining the temperature at several hundred degrees Celsius for several hours. This process not only consumes a large amount of electrical or fuel energy, significantly increasing costs, but the high temperatures also damage some of the activated carbon's structure, resulting in significant weight loss. While chemical regeneration methods have a certain regeneration efficiency, the complex subsequent reagent processing steps when using chemical reagents such as acid and alkali solutions can easily cause secondary pollution. Furthermore, the purchase, storage, use, and disposal of chemical reagents all require high investment, making cost control difficult.

[0006] Microwave regeneration technology utilizes the rapid and selective heating properties of microwaves to cause the polar molecules within activated carbon to vibrate rapidly and generate heat, thus quickly completing the regeneration process and minimizing damage to the activated carbon structure.

[0007] The inventors discovered that the current technology also has shortcomings. First, the temperature control during the regeneration process is not precise enough, which may cause localized overheating or underheating of the activated carbon, resulting in inconsistent regeneration effects and difficulty in consistently achieving the expected results. Second, in the microwave heating regeneration process, the activation gas is generally added through the gas inlet of the microwave regeneration device, i.e., introduced from one side and then distributed inside the microwave regeneration device. This method of introduction makes it difficult to ensure uniform contact between the activation gas and the activated carbon, thereby reducing activation efficiency and uniformity. Third, during the regeneration process, the waste granular activated carbon is piled up on the conveyor belt. The activated carbon on the surface is heated more fully and has more uniform contact with the activation gas, but the activated carbon in the interior is difficult to heat evenly and has difficulty making sufficient contact with the activation gas in a timely manner, thus making it difficult to guarantee the activation effect of the activated carbon. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a microwave regeneration device and method for waste granular activated carbon, which can solve problems such as unstable regeneration effect and high energy consumption.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] In a first aspect, the present invention provides a microwave regeneration device for waste granular activated carbon, comprising a shell, several microwave generators, several temperature sensors, a gas distributor, a stirrer, and a controller, wherein...

[0011] The microwave generators are arranged in a ring on the housing, and the resulting radiation surface is basically perpendicular to the running direction of the waste granular activated carbon.

[0012] The temperature sensors are evenly arranged on the inner wall of the housing;

[0013] The gas distributor is arranged around the waste granular activated carbon, and gas nozzles are evenly distributed on the gas distributor, with the gas nozzles facing inward.

[0014] Both the microwave generator and the temperature sensor are connected to the controller;

[0015] The agitator is equipped with multiple layers of agitator blades.

[0016] Multiple temperature sensors are evenly distributed on the inner wall of the housing, which can detect the temperature of relevant areas in a timely manner and feed the temperature information back to the controller. If the local temperature is too low, the controller controls the microwave generator in the relevant area to increase the heating temperature; if the local temperature is too high, the controller controls the microwave generator in the relevant area to decrease the heating temperature, so as to ensure the temperature uniformity and stability during the activated carbon regeneration process.

[0017] Multiple microwave generators are arranged in a ring to correspond to the activated carbon in different areas, thereby flexibly controlling the local temperature.

[0018] The gas distributor is arranged around the activated carbon, and the gas nozzles are evenly distributed on the gas distributor, so that the activation gas can be evenly sprayed onto the activated carbon.

[0019] The stirrer is equipped with multiple layers of stirring blades, which can fully stir the activated carbon at different depths. The stirrer and gas distributor work together to ensure that the activated carbon and the activating gas are in uniform and sufficient contact. The stirrer and the microwave reactor arranged in a ring work together to ensure that the activated carbon is subjected to uniform microwave radiation, so as to ensure that the activated carbon is heated evenly.

[0020] The above settings can effectively improve the uniformity and stability of activated carbon regeneration.

[0021] By directing the gas nozzle inwards and using air pressure to eject the activation gas at high speed, the concentration of activation gas near the waste granular activated carbon is increased, thereby improving the activation efficiency.

[0022] In some embodiments, the number of stirrers is 1-10. If the microwave regeneration device is large, the waste granular activated carbon can be spread thinly, and multiple stirrers can be used to mix the activated carbon evenly, which is beneficial to improving the activation efficiency and activation effect of the waste granular activated carbon.

[0023] In some embodiments, a cooling device is also included, which is connected to the discharge pipe of the microwave regeneration device.

[0024] Activated carbon that has been activated by microwave is at a high temperature. If it is directly discharged, it will be oxidized after contact with air. Therefore, a cooling device is needed to cool down the high-temperature activated carbon. However, air must be isolated during the cooling process.

[0025] For economic and efficiency reasons, the common method for cooling activated carbon is to directly contact it with cooling water for heat exchange. However, due to the high temperature of the activated carbon, a large amount of water is required for cooling. If the activated carbon is directly discharged into the water, the water resistance makes it difficult to ensure that the activated carbon is evenly distributed in the water, affecting the cooling efficiency. Furthermore, existing cooling devices are not effective at isolating the activated carbon from air.

[0026] Based on this, the inventors improved the structure of the cooling device in order to increase the cooling efficiency of activated carbon and provide good air isolation.

[0027] Preferably, the cooling device includes a housing and a filter screen, the housing including a cavity and a cover, the cover covering the top of the cavity;

[0028] The filter screen completely covers the bottom of the cavity and extends upwards along the inner wall of the outer shell.

[0029] The bottom of the cavity is provided with a groove, and one end of the groove is connected to a drain outlet.

[0030] The discharge pipe is connected to the water supply pipe, and the water supply pipe is set along the tangent of the discharge pipe.

[0031] The filter screen is placed at the bottom of the chamber to facilitate timely filtration of the cooled activated carbon. After cooling is complete, the cover can be opened, and the filter screen and activated carbon can be lifted out together by pulling around the edges of the filter screen.

[0032] To ensure the strength of the filter screen, it can be made of high-strength materials, and it can also have good flexibility.

[0033] The filtered wastewater is discharged through a groove at the bottom of the chamber. The groove is open after the filter screen is removed, and can be cleaned promptly if there is a lot of sediment in the groove.

[0034] The water supply pipe is installed tangentially to the discharge pipe, allowing cooling water to enter the discharge pipe tangentially. This creates a swirling flow in the discharge pipe, generating significant disturbance to the activated carbon. When the water volume is large, the activated carbon can be more thoroughly mixed in the water and carried into the cooling device by the water. This improves the fluidity of the activated carbon, facilitating its dispersion in a large volume of water. Furthermore, since the activated carbon is already in the water in the discharge pipe, the water effectively isolates it from external air, thus preventing oxidation.

[0035] More preferably, the number of water supply pipes is 1-4, and the inlets of each water supply pipe are arranged symmetrically.

[0036] In a further preferred embodiment, the filter screen is secured by ropes that extend out of the cavity through the cover.

[0037] More preferably, the connection port between the discharge pipe and the cooling device is located above the cooling device and above the filter screen. This ensures that the mixture of water and activated carbon can smoothly enter the cooling device.

[0038] Secondly, the present invention provides a microwave regeneration method for waste granular activated carbon, comprising the following steps:

[0039] The deactivated waste granular activated carbon is screened to remove large particulate impurities.

[0040] Waste granular activated carbon is fed into a microwave regeneration device, dried in a microwave at 150-200℃, and then pyrolyzed in a microwave at 500-600℃ for 10-40 minutes.

[0041] After microwave pyrolysis is completed, an activation gas is introduced into it, and activation and regeneration are carried out at 700-900℃ for 10-30 minutes.

[0042] The activated carbon is stirred during microwave drying, pyrolysis, and activation regeneration.

[0043] After activation, the activated carbon is mixed with water during the discharge process and then cooled in a cooling device.

[0044] In some embodiments, the stirring rate increases sequentially during microwave drying, pyrolysis, and activation regeneration. Stirring ensures the uniformity of activated carbon activation while preventing agglomeration.

[0045] In some embodiments, the activating gas is carbon dioxide, water vapor, or a mixture thereof.

[0046] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0047] (1) Precise temperature control: Through temperature sensors and feedback control systems, microwave power is monitored and adjusted in real time to ensure the temperature uniformity and stability of activated carbon during the regeneration process.

[0048] (2) Microwave field uniformity design: The coordinated operation of the ring-shaped microwave transmitter and the material stirring device effectively avoids the problem of local overheating or underheating of activated carbon, ensuring uniform heating and consistent regeneration effect during the regeneration process. At the same time, the frequency adjustment function and the variable frequency speed regulation function enable the device to adapt to the regeneration needs of different types and quantities of activated carbon; high-temperature resistant materials and optimized design improve the durability and reliability of the device.

[0049] (3) By introducing the gas at multiple points and precisely controlling the flow rate and pressure of the activating gas, the activation effect can be improved, which helps to accurately repair the pore structure of activated carbon, restore its adsorption performance, regenerate activated carbon more stably, and ensure the consistency of the quality and performance of the regenerated activated carbon.

[0050] (4) Energy consumption optimization: By dynamically adjusting the microwave power and recovering waste heat, the temperature uniformity of each area in the activated carbon regeneration device can be ensured, avoiding local overheating or insufficient heating, and improving the regeneration efficiency and adsorption performance of activated carbon; the power can be adjusted according to real-time temperature feedback to avoid unnecessary energy waste and reduce energy consumption. Attached Figure Description

[0051] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0052] Figure 1 This is a process flow diagram of the microwave regeneration method for waste granular activated carbon in an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram showing the arrangement of the microwave transmitter and the multi-point gas distributor in the microwave regeneration device of this invention.

[0054] Figure 3 for Figure 2 In the middle, a magnified view of a multi-point gas distributor at point A;

[0055] Figure 4 This is a schematic diagram of the cooling device in an embodiment of the present invention;

[0056] Figure 5 This is a cross-sectional view of the discharge pipe in an embodiment of the present invention.

[0057] Among them, 1-shell, 2-inner cavity, 3-first controller, 4-microwave transmitting unit, 5-microwave generator, 6-mounting structure, 7-temperature sensor, 8-gas distributor, 9-gas nozzle, 10-activating gas flow controller; 11-cooling device; 12-filter screen; 13-groove; 14-discharge pipe; 15-water supply pipe; 16-cover. Detailed Implementation

[0058] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0059] The present invention will be further described in detail below with reference to specific embodiments.

[0060] Example 1

[0061] like Figure 1 and Figure 2 As shown, the microwave regeneration device for waste granular activated carbon includes a housing 1, eight microwave generators 5, eight temperature sensors 7, a gas distributor 8, two stirrers, and a first controller 3.

[0062] The eight microwave generators 5 are arranged in a ring on the housing 1, and the radiation surface formed is perpendicular to the running direction of the waste granular activated carbon. Each microwave generator 5 is independently controlled and can dynamically adjust the microwave power output according to the feedback of the temperature sensor 7 to ensure the uniformity of the microwave field in space.

[0063] The eight temperature sensors 7 are evenly arranged on the inner wall of the housing 1. Multiple temperature sensors 7 distributed within the microwave regeneration device monitor the temperature distribution of the activated carbon in real time, and the data from the temperature sensors 7 is fed back to the intelligent control module. When the temperature of a certain area is detected to be lower than the set value, the first controller 3 increases the power of the microwave emitting unit near that area; when the temperature of a certain area is detected to be higher than the set value, the power of the microwave emitting unit near that area is reduced, thus saving energy and reducing consumption. By dynamically adjusting the microwave power, the temperature uniformity of each area during activated carbon regeneration is ensured.

[0064] like Figure 2 and Figure 3 As shown, the gas distributor 8 is arranged around the waste granular activated carbon, and gas nozzles are evenly distributed on the gas distributor 8, with the gas nozzles facing inward; the spacing between the gas nozzles is 15cm.

[0065] Both the microwave generator 5 and the temperature sensor 7 are connected to the first controller 3;

[0066] The agitator is equipped with multiple layers of agitator blades, with a spacing of 10cm between each layer of blades to ensure uniform mixing of activated carbon in the vertical direction. The agitator speed is adjustable, ranging from 30rpm: a lower speed (10rpm) is used in the low-temperature drying stage, and a higher speed (50rpm) is used in the high-temperature regeneration stage to avoid activated carbon clumping. The agitator blades and shaft are made of high-temperature resistant materials (such as silicon carbide or ceramic coating) to withstand high-temperature environments.

[0067] The microwave regeneration device has a capacity of 1.5m³. 3 .

[0068] like Figure 4 As shown, the cooling device is connected to the discharge pipe of the microwave regeneration device. The cooling device includes a shell and a filter screen 12. The shell includes a cavity and a cover 16, with the cover 16 covering the top of the cavity.

[0069] The filter screen 122 completely covers the bottom of the cavity and extends upward along the inner wall of the outer shell.

[0070] The bottom of the cavity is provided with a groove 13, and one end of the groove 13 is connected to the drain outlet.

[0071] like Figure 5 As shown, the discharge pipe 14 is connected to the water supply pipe 15, which is arranged tangentially to the discharge pipe 14. There are two water supply pipes. The filter screen 12 is secured with ropes that extend out of the cavity through the cover 16.

[0072] The connection port between the discharge pipe 14 and the cooling device is located above the cooling device and above the filter screen 12.

[0073] The microwave regeneration method for waste granular activated carbon includes the following steps:

[0074] 100 kg of saturated waste granular activated carbon was pretreated by screening and then fed into the microwave regeneration device using a screw feeder at a speed of 10 r / min.

[0075] Inside the microwave regeneration device, low-temperature drying is first performed. The drying temperature and time are set, and the temperature is raised to 150°C at a rate of 5°C / min and held for 10 minutes. During this process, the temperature distribution of the activated carbon is monitored in real time by a temperature sensor, and the microwave power is dynamically adjusted to ensure temperature uniformity.

[0076] Microwave pyrolysis regeneration and activation were then performed. The pyrolysis temperature and time were set, and the temperature was increased to 550℃ at a rate of 10℃ / min and held for 25 min. After microwave pyrolysis regeneration, the temperature was increased to 800℃ at a rate of 10℃ / min, while a mixture of carbon dioxide and water vapor (volume ratio 3:1) was introduced at a flow rate of 1 L / min and a pressure of 0.2 MPa. This temperature was maintained for 20 min. A mass flow controller was used to ensure stable flow and pressure of the activation gas to avoid differences in activation effect caused by uneven gas distribution.

[0077] After regeneration and activation, the material is conveyed to the discharge cooling device and cooled to below 60°C to obtain the microwave-regenerated activated carbon product. During this process, waste heat generated during regeneration is recovered and utilized through a waste heat recovery device, further reducing energy consumption.

[0078] Tests showed that the adsorption capacity was restored to 95% of that of new activated carbon, with an energy consumption of 0.8 kWh / kg.

[0079] Example 2

[0080] After screening another batch of 120 kg of adsorbed saturated granular activated carbon using the microwave regeneration device of Example 1, the material was fed into the microwave regeneration device at a screw feeder speed of 15 r / min.

[0081] Inside the microwave regeneration device, low-temperature drying is first performed. The drying temperature and time are set, and the temperature is raised to 180°C at a rate of 8°C / min and held for 12 minutes. During this process, the temperature distribution of the activated carbon is monitored in real time by a temperature sensor, and the microwave power is dynamically adjusted to ensure temperature uniformity.

[0082] Then, microwave pyrolysis regeneration and activation were performed. The pyrolysis temperature and time were set, and the temperature was increased to 600℃ at a heating rate of 12℃ / min and held for 30min. After the microwave pyrolysis regeneration was completed, the temperature was increased to 800℃ at a heating rate of 8℃ / min. At the same time, a mixture of carbon dioxide and water vapor (volume ratio 3:1) was introduced at a flow rate of 1L / min and a gas pressure of 0.3MPa. The gas was introduced at multiple points to ensure that the gas was in full contact with the activated carbon. The temperature was held for 15min.

[0083] After regeneration and activation, the material is conveyed to the discharge cooling device and cooled to below 50°C to obtain the microwave-regenerated activated carbon product. During this process, waste heat generated during regeneration is recovered and utilized through a waste heat recovery device, further reducing energy consumption.

[0084] The test results showed that the adsorption capacity was restored to 90% of that of new activated carbon, and the energy consumption was 1.0 kWh / kg.

[0085] Comparative Example 1

[0086] Comparison with Example 1:

[0087] The traditional regeneration method involves pre-treating saturated waste granular activated carbon through screening before feeding it into a thermal regeneration furnace. In the furnace, the carbon is first dried at a low temperature, then heated to 150°C at a rate of 5°C / min and held for 10 minutes. Next, it undergoes pyrolysis regeneration, being heated to 550°C at a rate of 10°C / min and held for 25 minutes.

[0088] Finally, activation was carried out by heating to 800°C at a heating rate of 10°C / min, while simultaneously introducing a mixture of carbon dioxide and water vapor (volume ratio 3:1) at a flow rate of 1L / min and a pressure of 0.2MPa, and maintaining this temperature for 20min.

[0089] After regeneration, the material is conveyed to a cooling device and cooled to below 60°C to obtain the regenerated activated carbon product.

[0090] The regenerated activated carbon has an adsorption capacity that is 88% of that of the new activated carbon, with an energy consumption of 1.5 kWh / kg.

[0091] Table 1 Comparison of data between Example 1 and Comparative Example 1

[0092]

[0093] As can be seen from the above embodiments and Table 1, the high-efficiency and energy-saving microwave regeneration method for granular activated carbon of the present invention has significant advantages in terms of temperature control, uniform heating, improved regeneration effect, reduced energy consumption, and protection of the quality of regenerated activated carbon.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A microwave regeneration device of spent granular activated carbon, characterized by: The microwave regeneration device for waste granular activated carbon comprises a shell, a plurality of microwave generators, a plurality of temperature sensors, a gas distributor, a stirrer and a controller, wherein, The plurality of microwave generators are arranged in a ring shape on the shell, and the radiation surface formed is substantially perpendicular to the running direction of the waste granular activated carbon; The plurality of temperature sensors are uniformly arranged on the inner wall of the shell; The gas distributor surrounds the waste granular activated carbon, and the gas distributor is uniformly provided with gas nozzles, which are arranged towards the inside; The microwave generators and the temperature sensors are connected with the controller; The stirrer is provided with a plurality of layers of stirring blades; The microwave regeneration device further comprises a cooling device connected with the discharge pipeline of the microwave regeneration device; The cooling device comprises a shell and a filter screen, the shell comprises a cavity and a cover, and the cover covers the top of the cavity; The filter screen completely covers the bottom of the cavity and extends upwards along the inner wall of the shell around the cavity; The bottom of the cavity is provided with a groove, one end of the groove is in communication with a drain port; The discharge pipeline is connected with a water supply pipe, and the water supply pipe is arranged along the tangent direction of the discharge pipeline; The filter screen is tied with a rope, and the rope extends out of the cavity through the cover and is fixed; The connection port of the discharge pipeline and the cooling device is located above the cooling device and above the filter screen.

2. The waste granular activated carbon microwave regeneration apparatus according to claim 1, characterized by: The number of the stirrers is 1-10.

3. The waste granular activated carbon microwave regeneration apparatus according to claim 1, characterized by: The number of the water supply pipes is 1-4, and the water inlets of the water supply pipes are arranged in an axisymmetric manner.

4. A method for microwave regeneration of spent granular activated carbon, characterized by: The microwave regeneration device for waste granular activated carbon according to any one of claims 1-3 is adopted; The method comprises the following steps: The deactivated waste granular activated carbon is screened to remove large particle impurities therefrom; The waste granular activated carbon is sent into the microwave regeneration device, dried by microwave at 150-200 DEG C, pyrolyzed by microwave at 500-600 DEG C for 10-40 min; After the microwave pyrolysis is completed, the activated gas is introduced thereinto, and the activated regeneration is performed at 700-900 DEG C for 10-30 min; During the microwave drying, pyrolysis and activated regeneration, the activated carbon is stirred; After the activation is completed, the activated carbon is mixed with water during the discharge process, and then enters the cooling device for cooling.

5. The method of claim 4, wherein the microwave regeneration of spent granular activated carbon is characterized by: During the microwave drying, pyrolysis and activated regeneration, the stirring rate is increased in turn.

6. The method for microwave regeneration of spent granular activated carbon according to claim 4, characterized in that: The activated gas is carbon dioxide, water vapor or a mixed gas thereof.

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