Microwave regeneration device and regeneration method for waste granular activated carbon

Abstract

The invention discloses a microwave regeneration device and regeneration method for waste granular active carbon, the microwave regeneration device comprises a shell, a plurality of microwave generators, a plurality of temperature sensors, a gas distributor, a stirrer and a controller, the plurality of microwave generators are annularly arranged on the shell, and the formed radiation surface is basically vertical to the running direction of the waste granular active 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, gas nozzles are uniformly distributed on the gas distributor, and the gas nozzles are arranged towards the inner side; the microwave generator and the temperature sensor are both connected with the controller; and a plurality of layers of stirring blades are arranged on the stirrer.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon regeneration, and in particular relates to a microwave regeneration device and a regeneration method for waste granular activated carbon. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

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

[0004] However, activated carbon will gradually become saturated with use. If the saturated activated carbon is directly discarded, serious consequences will occur. From a resource perspective, the preparation of activated carbon requires a large amount of raw materials such as wood and coal, as well as energy. Discarding it at will is a huge waste of resources. From an environmental perspective, if a large amount of discarded activated carbon enters the natural environment, the pollutants it adsorbs may be released again, causing pollution to the soil, water, atmosphere, etc., and destroying the ecological balance.

[0005] Therefore, activated carbon regeneration technology has become an inevitable choice. The traditional thermal regeneration method requires long-term heating at high temperature, such as maintaining the temperature at several hundred degrees Celsius for several hours. This process not only consumes a lot of electricity or fuel energy, which greatly increases the cost, but also the high temperature will cause part of the structure of the activated carbon to be destroyed, resulting in significant quality loss. Although the chemical regeneration method has a certain regeneration efficiency, when using chemical reagents such as acid and alkali solutions for regeneration, the subsequent complex reagent processing steps are prone to secondary pollution, and the purchase, storage, use and processing of chemical reagents require high investment, and the cost is difficult to control.

[0006] Microwave regeneration technology uses the characteristics of rapid and selective heating of microwaves to allow the polar molecules in the activated carbon to vibrate quickly to generate heat, which can quickly complete the regeneration process and reduce damage to the activated carbon structure.

[0007] The inventors found that the current technology also has defects. On the one hand, the temperature control during the regeneration process is not precise enough, which may cause local overheating or insufficient heating of the activated carbon, resulting in uneven regeneration effects and difficulty in achieving the expected stable results. On the second hand, during the microwave heating regeneration process, the activated gas is generally added from the gas inlet of the microwave regeneration device, that is, it is introduced from one side and then distributed inside the microwave regeneration device. With this introduction method, it is difficult to ensure uniform contact between the activated gas and the activated carbon, thereby reducing the activation efficiency and uniformity of activation. On the third hand, during the regeneration process, the waste granular activated carbon is piled on the conveyor belt in the form of a pile. The activated carbon on the surface is heated more fully and in contact with the activated gas more evenly, but the activated carbon located inside is difficult to be heated evenly and difficult to be in full contact with the activated gas in time, which makes it difficult to ensure the activation effect of the activated carbon. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a microwave regeneration device and a regeneration method for waste granular activated carbon, which can solve the problems of unstable activated carbon regeneration effect and high energy consumption.

[0009] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0010] In a first aspect, the present invention provides a microwave regeneration device for waste granular activated carbon, comprising a housing, a plurality of microwave generators, a plurality of temperature sensors, a gas distributor, an agitator and a controller, wherein:

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

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

[0013] The gas distributor is arranged around the waste granular activated carbon, and the gas nozzles are evenly distributed on the gas distributor, and the gas nozzles are arranged toward the inside;

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

[0015] The stirrer is provided with multiple layers of stirring blades.

[0016] Multiple temperature sensors are evenly arranged on the inner wall of the shell, which can detect the temperature of the relevant area in time and feed back the temperature information 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 lower the heating temperature to ensure the temperature uniformity and stability during the activated carbon regeneration process.

[0017] Multiple microwave generators are arranged in a ring shape so as to correspond to activated carbon in different areas, thereby flexibly adjusting 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 activated gas can be evenly sprayed onto the activated carbon.

[0019] The agitator is provided with multiple layers of stirring blades, which can fully and evenly stir the activated carbon at different depths. The agitator and the gas distributor work together to ensure that the activated carbon is in uniform and sufficient contact with the activation gas; the agitator and the microwave reactor arranged in a ring work together to ensure that uniform microwave radiation is applied to the activated carbon to ensure that the activated carbon is evenly heated.

[0020] Through the above settings, the regeneration uniformity and stability of activated carbon can be effectively improved.

[0021] The gas nozzle is arranged to face inwards, and the activated gas is ejected at high speed using gas pressure, which is beneficial to increasing the concentration of the activated gas near the location of the waste granular activated carbon, thereby helping to improve the activation efficiency.

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

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

[0024] The temperature of the activated carbon after microwave activation is relatively high. If it is discharged directly, it will be oxidized after contacting the air. Therefore, a cooling device is needed to cool the high-temperature activated carbon, but the air needs to be isolated during the cooling process.

[0025] For the sake of economy and efficiency, high-temperature activated carbon is generally cooled by direct contact heat exchange between cooling water and high-temperature activated carbon. Since the temperature of activated carbon is high, a large amount of water is required for cooling. If activated carbon is directly discharged into water, it is difficult to ensure uniform distribution of activated carbon in water due to water resistance, which affects the cooling efficiency of activated carbon. In addition, existing cooling devices are difficult to effectively isolate air.

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

[0027] Preferably, the cooling device comprises a housing and a filter screen, the housing comprises a cavity and a cover, and the cover covers the top of the cavity;

[0028] The filter screen completely covers the bottom of the cavity and extends upward along the inner wall of the shell;

[0029] The bottom of the cavity is provided with a groove, one end of which is connected to the drain port;

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

[0031] The filter screen is arranged to cover the bottom of the cavity, so as to facilitate timely filtering of the activated carbon after cooling. When cooling is completed, the cover can be opened, and the filter screen together with the activated carbon can be lifted out by pulling the four sides of the filter screen.

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

[0033] The wastewater discharged by filtration is discharged through the groove at the bottom of the cavity. When the filter is removed, the groove is open. If there is a lot of sediment in the groove, it can be cleaned in time.

[0034] The water supply pipe is arranged tangentially along the discharge pipe, so that the cooling water enters the discharge pipe along the tangential direction of the discharge pipe, forming a vortex in the discharge pipe, which will produce a large disturbance force on the activated carbon therein. When the amount of water is large, the activated carbon can be more fully mixed in the water and enter the cooling device under the carry of water. On the one hand, the fluidity of the activated carbon is improved, which is conducive to promoting the dispersion of the activated carbon in a larger volume of water; on the other hand, the activated carbon has already entered the water in the discharge pipe, and the water can effectively isolate the outside air from contacting the activated carbon, thereby effectively preventing the oxidation of the activated carbon.

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

[0036] Further preferably, ropes are tied around the filter screen, and the ropes are extended out of the cavity through the cover body for fixation.

[0037] Further preferably, the connection port between the discharge pipe and the cooling device is located above the cooling device and above the filter screen, so as to ensure that the mixture of water and activated carbon can smoothly enter the interior of the cooling device.

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

[0039] Screen the deactivated waste granular activated carbon to remove large particle impurities;

[0040] The waste granular activated carbon is sent to a microwave regeneration device, and after microwave drying at 150-200°C, microwave pyrolysis is performed at 500-600°C for 10-40 minutes;

[0041] After microwave pyrolysis is completed, activation gas is introduced into the catalyst to perform activation regeneration at 700-900°C for 10-30 minutes;

[0042] During microwave drying, pyrolysis and activation regeneration, the activated carbon is stirred;

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

[0044] In some embodiments, the stirring rate increases successively during microwave drying, pyrolysis and activation regeneration. Stirring ensures the uniformity of activated carbon activation on the one hand, and prevents activated carbon from agglomerating on the other hand.

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

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

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

[0048] (2) Microwave field uniformity design: The coordinated work of the ring-shaped microwave emitter and the material stirring device effectively avoids the problem of local overheating or insufficient heating of the activated carbon, ensuring that the activated carbon is evenly heated during the regeneration process and the regeneration effect is consistent. At the same time, the frequency adjustment function and 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 activated gas at multiple points and precisely controlling its flow rate and pressure, the activation effect is improved, which helps to accurately repair the pore structure of the activated carbon, restore its adsorption performance, and regenerate the activated carbon more stably, thus ensuring the consistency of the quality and performance of the regenerated activated carbon.

[0050] (4) Energy consumption optimization: By dynamically adjusting the microwave power and recycling waste heat, the temperature uniformity of each area in the activated carbon regeneration device can be ensured, local overheating or insufficient heating can be avoided, and the regeneration efficiency and adsorption performance of the activated carbon can be improved; the power can be adjusted according to real-time temperature feedback to avoid unnecessary energy waste and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

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

[0053] Figure 2 It is a schematic diagram of the arrangement of the microwave emitter and the multi-point gas distributor of the microwave regeneration device in the embodiment of the present invention;

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

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

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

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

[0058] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0059] The present invention is further described in detail below in conjunction with 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, 8 microwave generators 5, 8 temperature sensors 7, a gas distributor 8, 2 stirrers and a first controller 3, wherein:

[0062] The eight microwave generators 5 are arranged in a ring shape 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 shell 1; the temperature distribution of the activated carbon is monitored in real time by multiple temperature sensors 7 distributed in the microwave regeneration device, and the data of the temperature sensors 7 are fed back to the intelligent control module. When it is detected that the temperature of a certain area is lower than the set value, the first controller 3 increases the power of the microwave transmitting unit near the area; when it is detected that the temperature of a certain area is higher than the set value, the power of the microwave transmitting unit near the area is reduced to save energy and reduce consumption. By dynamically adjusting the microwave power, the temperature uniformity of each area of ​​the 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 the gas distributor 8 is evenly distributed with gas nozzles, which are arranged toward the inside; the spacing between the gas nozzles is 15 cm.

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

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

[0067] The capacity of the microwave regeneration device is 1.5m 3 .

[0068] like Figure 4 As shown, the cooling device is connected to the discharge pipe of the microwave regeneration device, and the cooling device includes a shell and a filter 12, and the shell includes a cavity and a cover 16, and the cover 16 covers 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 shell;

[0070] The bottom of the cavity is provided with a groove 13, one end of which is connected to the drain port;

[0071] like Figure 5 As shown, the discharge pipe 14 is connected to a water supply pipe 15, which is arranged tangentially to the discharge pipe 14, and the number of the water supply pipes is 2. Ropes are tied around the filter screen 12, and the ropes extend out of the cavity through the cover body 16 for fixing.

[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 of waste granular activated carbon comprises the following steps:

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

[0075] In the microwave regeneration device, low-temperature drying is first performed, and the drying temperature and time are set, and the temperature is heated to 150°C at a heating rate of 5°C / min and maintained 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] Then, microwave pyrolysis regeneration and activation were performed, and the pyrolysis temperature and time were set, and the temperature was increased to 550°C at a rate of 10°C / min, and maintained for 25 minutes; after the microwave pyrolysis regeneration was completed, the temperature was increased to 800°C at a rate of 10°C / min, and a mixed gas of carbon dioxide and water vapor (volume ratio 3:1) was introduced at the same time, the gas flow rate was 1L / min, and the gas pressure was 0.2MPa, and maintained at this temperature for 20 minutes. The mass flow controller was used to ensure the stability of the flow and pressure of the activation gas to avoid differences in activation effects caused by uneven gas distribution.

[0077] After the regeneration and activation is completed, the material is transported to the discharge cooling device and cooled to below 60°C to obtain the activated carbon product after microwave regeneration. In this process, the waste heat generated during the regeneration process is recycled and utilized through the waste heat recovery device to further reduce energy consumption.

[0078] After testing, the adsorption capacity was restored to 95% of the new activated carbon, and the energy consumption was 0.8kWh / kg.

[0079] Example 2

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

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

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

[0083] After the regeneration and activation is completed, the material is transported to the discharge cooling device and cooled to below 50°C to obtain the activated carbon product after microwave regeneration. In this process, the waste heat generated during the regeneration process is recycled and utilized through the waste heat recovery device to further reduce energy consumption.

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

[0085] Comparative Example 1

[0086] Compared with Example 1:

[0087] The traditional regeneration method is: the adsorption saturated waste granular activated carbon is sent to the thermal regeneration furnace after screening and pretreatment. In the thermal regeneration furnace, it is first dried at low temperature, heated to 150℃ at a heating rate of 5℃ / min, and kept for 10 minutes. Then it is pyrolyzed and regenerated, heated to 550℃ at a heating rate of 10℃ / min, and kept for 25 minutes.

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

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

[0090] The adsorption capacity of the regenerated activated carbon was restored to 88% of the new activated carbon, and the energy consumption was 1.5 kWh / kg.

[0091] Table 1 Data comparison between Example 1 and Comparative Example 1

[0092]

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

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A microwave regeneration device for waste granular activated carbon, characterized in that: It includes a housing, several microwave generators, several temperature sensors, a gas distributor, an agitator and a controller, wherein: The microwave generators are arranged in a ring shape on the housing, and the radiation surface formed is substantially perpendicular to the running direction of the waste granular activated carbon; The plurality of temperature sensors are evenly arranged on the inner wall of the shell; The gas distributor is arranged around the waste granular activated carbon, and the gas nozzles are evenly distributed on the gas distributor, and the gas nozzles are arranged toward the inside; The microwave generator and the temperature sensor are both connected to the controller; The stirrer is provided with multiple layers of stirring blades.

2. The microwave regeneration device for waste granular activated carbon according to claim 1, characterized in that: The number of the agitators is 1-10.

3. The microwave regeneration device for waste granular activated carbon according to claim 1, characterized in that: It also includes a cooling device, which is connected to the discharge pipe of the microwave regeneration device.

4. The microwave regeneration device for waste granular activated carbon according to claim 3, characterized in that: 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 upward along the inner wall of the shell; The bottom of the cavity is provided with a groove, one end of which is connected to the drain port; The discharge pipe is connected to a water supply pipe, and the water supply pipe is arranged along the tangent direction of the discharge pipe.

5. The microwave regeneration device for waste granular activated carbon according to claim 4, characterized in that: The number of the water supply pipes is 1-4, and the water inlets of the water supply pipes are axially symmetrically arranged.

6. The microwave regeneration device for waste granular activated carbon according to claim 4, characterized in that: Ropes are tied around the filter screen, and the ropes extend out of the cavity through the cover body for fixing.

7. The microwave regeneration device for waste granular activated carbon according to claim 4, characterized in that: The connection port between the discharge pipe and the cooling device is located above the cooling device and above the filter screen.

8. A microwave regeneration method for waste granular activated carbon, characterized in that: The steps include: Screen the deactivated waste granular activated carbon to remove large particle impurities; The waste granular activated carbon is sent to a microwave regeneration device, and after microwave drying at 150-200°C, microwave pyrolysis is performed at 500-600°C for 10-40 minutes; After microwave pyrolysis is completed, activation gas is introduced into the catalyst to perform activation regeneration at 700-900°C for 10-30 minutes; During microwave drying, pyrolysis and activation regeneration, the activated carbon is stirred; After activation, the activated carbon is mixed with water during discharge and then enters a cooling device for cooling.

9. The microwave regeneration method of waste granular activated carbon according to claim 8, characterized in that: During microwave drying, pyrolysis and activation regeneration, the stirring rate increased successively.

10. The microwave regeneration method of waste granular activated carbon according to claim 8, characterized in that: The activated gas is carbon dioxide, water vapor or a mixed gas thereof.

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