Regeneration method of oil-containing activated carbon

Abstract

The invention belongs to the technical field of oil-containing activated carbon regeneration, and particularly relates to an oil-containing activated carbon regeneration method which comprises the following steps: mixing oil-containing activated carbon with a surfactant, and performing ultrasonic treatment to obtain first oil-containing activated carbon; extracting the first oil-containing activated carbon by adopting supercritical carbon dioxide to obtain second oil-containing activated carbon and a first oil component, and recovering the first oil component; and treating the second oil-containing activated carbon by adopting microwaves to obtain regenerated activated carbon and a second oil component, and recovering the second oil component. According to the method, a low-temperature treatment process is adopted in the whole process, active carbon structure damage caused by high temperature is avoided, the coking rate is low, and energy is greatly saved; through supercritical carbon dioxide extraction and microwave desorption of oil, oil resources are recycled, and no harmful substance is generated in the process; by adopting a multi-stage regeneration process, oil in the oil-containing activated carbon can be effectively desorbed, and the regenerated activated carbon is high in adsorption capacity recovery rate and low in energy consumption.

Description

Technical Field

[0001] This application belongs to the technical field of regeneration of oil-containing activated carbon, and specifically relates to a regeneration method for oil-containing activated carbon. Background Art

[0002] In the wastewater (raffinate) generated after the extraction process in the hydrometallurgy industry to recover products, there is often oil content. If it is directly subjected to MVR evaporation without treatment, it will not only affect the evaporation efficiency, damage the equipment, but also have high energy consumption and low purity of the by-product salt produced. The oil components in the raffinate are mainly composed of phosphate ester extractants (P204, P507, CY272), solvent oil No. 260 and its decomposition products. The common treatment methods mainly include using materials such as oil removal resins and activated carbon for oil adsorption. In particular, activated carbon has been widely used due to its strong adsorption capacity, large adsorption amount, and fast adsorption rate. After the activated carbon is saturated with adsorption, it is desorbed and decomposed of oil components through high-temperature thermal regeneration method, chemical regeneration method, and microbial regeneration method to obtain regenerated activated carbon. However, the above methods have a series of disadvantages such as high energy consumption, high burn-off rate of activated carbon, large amount of chemical reagents, long treatment time, and decreased adsorption capacity after regeneration. Therefore, there is an urgent need to develop a new type of regeneration technology for oil-containing activated carbon.

[0003] Patent CN111889090A discloses a method for regenerating activated carbon by high-temperature pyrolysis, using carboxylated ionic liquid and sodium salt as activated carbon regeneration aids, and then obtaining regenerated activated carbon through processes such as high-temperature carbonization and steam activation. This method has high energy consumption and a large loss of activated carbon.

[0004] Patent CN115970666A discloses an activated carbon regeneration process, which obtains regenerated activated carbon by ultrasonic stirring pickling, removing residual acid, high-temperature carbonization, and activation. This method also has relatively high energy consumption and is prone to generating toxic gases.

[0005] Patent CN119186539A discloses a method for regenerating activated carbon based on ultrasonic coupling, using temperature-controlled ultrasonic vibration to adjust the pH of the reaction solution to achieve the purpose of regenerating activated carbon. This method has low regeneration efficiency of activated carbon and consumes chemical reagents such as acids and bases.

[0006] Patent CN118874448A discloses a renewable disposal method for waste activated carbon, which obtains regenerated activated carbon by microwave high-temperature heating desorption technology. The practical effect of this method is poor and the desorption effect is not good.

[0007] Patent KR20230040647A discloses a method for graded regeneration of activated carbon using ozone and supercritical carbon dioxide. In this method, ozone and supercritical carbon dioxide are both supplied to the same regeneration reactor to treat the activated carbon. Since ozone and high-pressure carbon dioxide react to produce atomic oxygen, the reaction vessel needs to be made of high-pressure and corrosion-resistant materials, which greatly increases the cost and poses safety risks. Summary of the invention

[0008] In view of the problems existing in the above-mentioned prior art, the present application provides a method for regenerating oil-containing activated carbon. The method in the present application can not only obtain regenerated activated carbon with high adsorption capacity and low coking rate, but also recover oil resources, thereby achieving the dual effects of resource recycling and recovery.

[0009] A method for regenerating oil-containing activated carbon in the present application comprises the following steps: S1, mixing the oil-containing activated carbon with a surfactant, and then subjecting the mixture to ultrasonic treatment to obtain a first oil-containing activated carbon; S2, extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and a first oil component, and recovering the first oil component; S3. Treat the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil component, and recover the second oil component.

[0010] In the above technical scheme, after the surfactant is mixed with the oil-containing activated carbon in step S1, the hydrophobic end of the surfactant is embedded in the oil film, and the hydrophilic end extends into the water phase, thereby reducing the interfacial tension and breaking the oil film into tiny oil droplets; ultrasonic treatment is then performed to accelerate the destruction of the oil film and the surface binding layer of the activated carbon, thereby achieving the purpose of pretreatment. If ultrasonic treatment is not performed first, the effect of the subsequent treatment process will be reduced due to the presence of the oil film and the surface binding layer, which is disadvantageous in terms of performance and cost; the heavy oil (the first oil component) with high boiling point, large molecules and high viscosity in the oil-containing activated carbon usually needs to be dissolved under low temperature and high pressure, while the supercritical fluid Carbon oxide can efficiently dissolve non-polar heavy oil, and the reaction conditions meet the requirements, so supercritical carbon dioxide is used to extract and recover it in step S2; during microwave treatment in step S3, under the action of the microwave field, water and polar oil molecules rotate at high speed, resulting in frictional heat between molecules, while the temperature of the activated carbon skeleton rises slowly, selectively separating oil and water from the activated carbon. In addition, the microwave electric field changes the molecular energy level and weakens the binding energy between the oil and the activated carbon, that is, the van der Waals force decreases, promoting oil desorption. The purpose of this step is to separate and recover light oil (the second oil) with low boiling point, small molecules and low viscosity.

[0011] The reasons for first using supercritical carbon dioxide extraction and then microwave treatment are as follows: 1. To avoid coking. The microwave reaction temperature is relatively high. If microwave heating treatment is carried out first, the heavy oil will carbonize and coke, blocking the pores of the activated carbon. 2. To improve the purity of oil recovery. Supercritical carbon dioxide preferentially extracts heavy oil, and the purity of the recovered heavy oil > 90%, with almost no light oil mixed. Microwave treatment recovers the light oil components by heating and condensation, with a purity > 85%, thus realizing the hierarchical utilization of heavy and light oils. 3. To reduce energy consumption. The supercritical carbon dioxide extraction reaction conditions are at low temperature, while the temperature required for microwave treatment is relatively high. Adopting the technical route of removing heavy oil at low temperature and light oil at high temperature, the microwave only needs to treat a small amount of residual light oil, and the overall energy consumption is lower. 4. To increase safety. If microwave treatment is carried out first, the coking products generated will block the high-pressure pipeline, increasing the risk factor under high temperature and high pressure conditions.

[0012] Further, after step S3, it further includes: S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon.

[0013] In step S4, the ozone decomposes to generate free radicals that attack the oil molecules, break the binding bonds of the oil molecules, and cause the decomposition of the oil. The purpose is to decompose the small amount of residual organic matter in the regenerated activated carbon, repair the specific surface area of the activated carbon, and further restore the adsorption performance of the regenerated activated carbon. Placing this step after supercritical carbon dioxide extraction and microwave treatment can reduce costs, improve safety, and at the same time enhance the reaction efficiency.

[0014] Further, in step S1, the surfactant includes at least one of rhamnolipid or sophorolipid, and the mass of the surfactant is 0.02% - 0.2% of the mass of the oil-containing activated carbon; preferably, 0.1% rhamnolipid and 0.05% sophorolipid are used in combination. Continuing to increase the dosage has little improvement in effect and wastes reagents.

[0015] Further, in step S1, the frequency of the ultrasonic wave is 20 - 50 kHz.

[0016] Further, in step S1, the time for ultrasonic treatment is 10 - 60 min.

[0017] Further, in step S2, the temperature for extracting the first oil-containing activated carbon with supercritical carbon dioxide is 35 - 60 °C, the pressure is 7.5 - 12 MPa, and the time is 5 - 30 min.

[0018] Further, in step S3, the power of the microwave is 0.5 - 2 W / g.

[0019] Further, in step S3, the temperature for treating the second oil-containing activated carbon with microwave is 60 - 120 °C, and the time is 5 - 30 min.

[0020] Further, in step S4, the concentration of ozone is 50 - 300 ppm; the time for treating the regenerated activated carbon with ozone is 5 - 30 min.

[0021] Further, in step S2, the first oil fraction includes organic substances with a molecular weight ≥ 200; in step S3, the second oil fraction includes organic substances with a molecular weight < 200.

[0022] The present application provides a method for regenerating oil - containing activated carbon, which has the following beneficial effects: The whole process adopts a low - temperature treatment process, avoiding the destruction of the activated carbon structure caused by high temperature, with a low coking rate and greatly saving energy; through supercritical carbon dioxide extraction and microwave desorption of oil fractions, oil resources are recovered, and no harmful substances are generated during the process; adopting a multi - stage regeneration process can effectively desorb the oil fractions in the oil - containing activated carbon, and the adsorption capacity recovery rate of the regenerated activated carbon is high and the energy consumption is low. Detailed implementation manners

[0023] The technical solutions in the embodiments will be described clearly and completely below. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0024] The technical solutions proposed in the present application include the following steps: S1. Mix the oil - containing activated carbon with a surfactant and then perform ultrasonic treatment to obtain the first oil - containing activated carbon; Specifically, the adsorption capacity of the oil - containing activated carbon ≤ 66.8 g / kg, and the surfactant used includes at least one of rhamnolipid or sophorolipid, and its mass is 0.02% - 0.2% of the mass of the oil - containing activated carbon. The preferred dosage is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid; the frequency of the ultrasonic wave is 20 - 50 kHz, and the time for ultrasonic treatment is 10 - 60 min; specifically, the frequency of the ultrasonic wave is any one or the range between any two of 20 kHz, 30 kHz, 40 kHz, 50 kHz, and the time for ultrasonic treatment is any one or the range between any two of 10 min, 20 min, 30 min, 40 min, 50 min, 60 min.

[0025] S2. Extract the first oil - containing activated carbon with supercritical carbon dioxide to obtain the second oil - containing activated carbon and the first oil fraction, and recover the first oil fraction; Specifically, the first oil fraction includes organic substances with a molecular weight ≥ 200. The temperature during extraction is 35 - 60°C, the pressure is 7.5 - 12 MPa, and the time is 5 - 30 min. Specifically, the temperature during extraction is any one or the range between any two of 35°C, 40°C, 45°C, 50°C, 55°C, 60°C; the pressure during extraction is any one or the range between any two of 7.5 MPa, 8.5 MPa, 9.5 MPa, 10.5 MPa, 11.5 MPa, 12 MPa; and the extraction time is any one or the range between any two of 5 min, 15 min, 25 min, 30 min.

[0026] S3. Treat the second oil - containing activated carbon with microwave to obtain regenerated activated carbon and the second oil fraction, and recover the second oil fraction. Specifically, the second oil fraction includes organic substances with a molecular weight < 200. The power of the microwave is 0.5 - 2 W / g, the temperature during microwave treatment is 60 - 120°C, and the time is 5 - 30 min. Specifically, the power of the microwave is any one or the range between any two of 0.5 W / g, 1.0 W / g, 1.5 W / g, 2.0 W / g; the temperature during microwave treatment is any one or the range between any two of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C; and the time of microwave treatment is any one or the range between any two of 5 min, 15 min, 25 min, 30 min.

[0027] In order to further restore the adsorption performance of the regenerated activated carbon, after step S3, it further includes: S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 50 - 300 ppm, and the time of ozone treatment is 5 - 30 min. Specifically, the concentration of ozone is any one or the range between any two of 50 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm; and the time of ozone treatment is any one or the range between any two of 5 min, 15 min, 25 min, 30 min.

[0028] The technical solution of the present application will be further described below in conjunction with specific embodiments.

[0029] The activated carbon used in each example and comparative example is oil - containing activated carbon with saturated adsorption, and its saturated adsorption capacity is 66.8 g / kg.

[0030] Example 1 A method for regenerating oil - containing activated carbon includes the following steps: S1. Mix the oil-containing activated carbon with a surfactant and then perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the frequency of the ultrasonic wave is 30 kHz, and the time of the ultrasonic treatment is 20 min. S2. Extract the first oil-containing activated carbon with supercritical carbon dioxide to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 40 °C, the pressure is 8.5 MPa, and the time is 10 min. S3. Treat the second oil-containing activated carbon with microwave to obtain the regenerated activated carbon and the second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 1.0 W / g, the temperature during the microwave treatment is 80 °C, and the time is 10 min. To further verify the effect of the regenerated activated carbon, take the regenerated activated carbon in Example 1 above for an oil adsorption experiment, and obtain its coking rate of 4.7%, adsorption saturation capacity of 46.1 g / kg, adsorption performance recovery rate of 69%, and energy consumption of 0.8 kWh / kg.

[0031] Example 2 A method for regenerating oil-containing activated carbon includes the following steps: S1. Mix the oil-containing activated carbon with a surfactant and then perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the frequency of the ultrasonic wave is 30 kHz, and the time of the ultrasonic treatment is 20 min. S2. Extract the first oil-containing activated carbon with supercritical carbon dioxide to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 40 °C, the pressure is 8.5 MPa, and the time is 10 min. S3. Treat the second oil-containing activated carbon with microwave to obtain the regenerated activated carbon and the second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 1.0 W / g, the temperature during the microwave treatment is 80 °C, and the time is 10 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 100 ppm, and the time of the ozone treatment is 10 min.

[0032] To further verify the effect of the second regenerated activated carbon, take the second regenerated activated carbon in Example 2 above for an oil adsorption experiment, and obtain its coking rate of 1.3%, adsorption saturation capacity of 61.5 g / kg, adsorption performance recovery rate of 92%, and energy consumption of 1.1 kWh / kg.

[0033] Example 3 A method for regenerating oil-containing activated carbon includes the following steps: S1. After mixing the oil-containing activated carbon with a surfactant, perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the frequency of the ultrasonic wave is 20 kHz, and the time of the ultrasonic treatment is 10 min. S2. Use supercritical carbon dioxide to extract the first oil-containing activated carbon to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 35 °C, the pressure is 7.5 MPa, and the time is 5 min. S3. Treat the second oil-containing activated carbon with microwave to obtain the regenerated activated carbon and the second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 0.5 W / g, the temperature during the microwave treatment is 60 °C, and the time is 5 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 50 ppm, and the time of the ozone treatment is 5 min.

[0034] To further verify the effect of the second regenerated activated carbon, take the second regenerated activated carbon in Example 3 above for an oil fraction adsorption experiment, and obtain its coking rate of 0.5%, adsorption saturation capacity of 32.1 g / kg, adsorption performance recovery rate of 48%, and energy consumption of 0.9 kWh / kg.

[0035] Example 4 A method for regenerating oil-containing activated carbon, comprising the following steps: S1. After mixing the oil-containing activated carbon with a surfactant, perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the frequency of the ultrasonic wave is 50 kHz, and the time of the ultrasonic treatment is 60 min. S2. Use supercritical carbon dioxide to extract the first oil-containing activated carbon to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 60 °C, the pressure is 12 MPa, and the time is 30 min. S3. Treat the second oil-containing activated carbon with microwave to obtain the regenerated activated carbon and the second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 2 W / g, the temperature during the microwave treatment is 120 °C, and the time is 30 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 300 ppm, and the time of the ozone treatment is 30 min.

[0036] To further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon from Example 4 above was used for an oil adsorption experiment, and its coking rate was found to be 16%, the adsorption saturation capacity was 49.4 g / kg, the adsorption performance recovery rate was 74%, and the energy consumption was 2.7 kWh / kg.

[0037] Example 5 A method for regenerating oil-containing activated carbon, comprising the following steps: S1. After mixing the oil-containing activated carbon with a surfactant, perform ultrasonic treatment to obtain a first oil-containing activated carbon; specifically, 0.1% rhamnolipid and 0.05% sophorolipid are used in combination as the surfactant, the frequency of the ultrasonic wave is 30 kHz, and the ultrasonic treatment time is 30 min; S2. Use supercritical carbon dioxide to extract the first oil-containing activated carbon to obtain a second oil-containing activated carbon and a first oil fraction, and recover the first oil fraction; specifically, the temperature during extraction is 60 °C, the pressure is 7.5 MPa, and the time is 10 min; S3. Use microwave to treat the second oil-containing activated carbon to obtain regenerated activated carbon and a second oil fraction, and recover the second oil fraction; specifically, the power of the microwave is 1.5 W / g, the temperature during microwave treatment is 120 °C, and the time is 10 min; S4. Treat the regenerated activated carbon with ozone to obtain a second regenerated activated carbon; specifically, the concentration of ozone is 100 ppm, and the ozone treatment time is 10 min.

[0038] To further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon from Example 5 above was used for an oil adsorption experiment, and its coking rate was found to be 7.5%, the adsorption saturation capacity was 54.1 g / kg, the adsorption performance recovery rate was 81%, and the energy consumption was 1.6 kWh / kg.

[0039] Example 6 A method for regenerating oil-containing activated carbon, comprising the following steps: S1. After mixing the oil-containing activated carbon with a surfactant, perform ultrasonic treatment to obtain a first oil-containing activated carbon; specifically, 0.1% rhamnolipid and 0.05% sophorolipid are used in combination as the surfactant, the frequency of the ultrasonic wave is 30 kHz, and the ultrasonic treatment time is 20 min; S2. Use supercritical carbon dioxide to extract the first oil-containing activated carbon to obtain a second oil-containing activated carbon and a first oil fraction, and recover the first oil fraction; specifically, the temperature during extraction is 40 °C, the pressure is 8.5 MPa, and the time is 10 min; S3. Treat the second oil-containing activated carbon with microwave to obtain regenerated activated carbon and a second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 1.5 W / g, the temperature during microwave treatment is 120 °C, and the time is 10 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 100 ppm, and the time of ozone treatment is 10 min.

[0040] To further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon in Example 6 above was used for an oil fraction adsorption experiment, and its coking rate was 4.3%, the adsorption saturation capacity was 56.8 g / kg, the adsorption performance recovery rate was 85%, and the energy consumption was 1.3 kWh / kg.

[0041] Comparative Example 1 A method for regenerating oil-containing activated carbon includes the following steps: S1. Directly perform ultrasonic treatment on the oil-containing activated carbon to obtain the first oil-containing activated carbon. Specifically, the frequency of the ultrasonic wave is 20 kHz, and the time of ultrasonic treatment is 10 min. S2. Extract the first oil-containing activated carbon with supercritical carbon dioxide to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 35 °C, the pressure is 7.5 Mpa, and the time is 5 min. S3. Treat the second oil-containing activated carbon with microwave to obtain regenerated activated carbon and a second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 0.5 W / g, the temperature during microwave treatment is 60 °C, and the time is 5 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 50 ppm, and the time of ozone treatment is 5 min.

[0042] In this comparative example, except for not using a surfactant, other conditions are the same as in Example 3. The coking rate of its second regenerated activated carbon is 0.7%, the adsorption saturation capacity is 23.4 g / kg, the adsorption performance recovery rate is 35%, the energy consumption is 0.9 kWh / kg, and the adsorption performance recovery rate is lower than that in Example 3.

[0043] Comparative Example 2 A method for regenerating oil-containing activated carbon includes the following steps: S1. Extract the oil-containing activated carbon with supercritical carbon dioxide to obtain the first oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 40 °C, the pressure is 8.5 MPa, and the time is 10 min. S3. Treat the first oil-containing activated carbon with microwave to obtain regenerated activated carbon and a second oil fraction, and recover the second oil fraction. Specifically, the power of the microwave is 1.0 W / g, the temperature during microwave treatment is 80 °C, and the time is 10 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 100 ppm, and the time of ozone treatment is 10 min.

[0044] In this comparative example, except for not using a surfactant and not performing ultrasonic treatment, other conditions are the same as those in Example 2. The coking rate of the second regenerated activated carbon is 1.2%, the adsorption saturation capacity is 46.1 g / kg, the adsorption performance recovery rate is 69%, the energy consumption is 1.0 kWh / kg, and the adsorption performance recovery rate is significantly lower than that in Example 2.

[0045] Comparative Example 3 S1. Mix the oil-containing activated carbon with a surfactant and then perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the frequency of the ultrasonic wave is 30 kHz, and the time of ultrasonic treatment is 20 min. S2. Treat the first oil-containing activated carbon with microwave to obtain regenerated activated carbon. Specifically, the power of the microwave is 1.0 W / g, the temperature during microwave treatment is 80 °C, and the time is 10 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 100 ppm, and the time of ozone treatment is 10 min.

[0046] In this comparative example, except for not using supercritical carbon dioxide extraction, other conditions are the same as those in Example 2. The coking rate of the second regenerated activated carbon is 21.7%, the adsorption saturation capacity is 26.7 g / kg, the adsorption performance recovery rate is 40%, the energy consumption is 1.0 kWh / kg, the coking rate is significantly higher than that in Example 2, and the adsorption performance recovery rate is significantly lower than that in Example 2.

[0047] Comparative Example 4 A regeneration method for oil-containing activated carbon includes the following steps: S1. Mix the oil-containing activated carbon with a surfactant and then perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the frequency of the ultrasonic wave is 30 kHz, and the time of ultrasonic treatment is 20 min. S2. Extract the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and a first oil fraction, and recover the first oil fraction. Specifically, the temperature during extraction is 40 °C, the pressure is 8.5 MPa, and the time is 10 min. S3. Treat the second oil-containing activated carbon with ozone to obtain regenerated activated carbon. Specifically, the concentration of ozone is 100 ppm, and the ozone treatment time is 10 min.

[0048] In this comparative example, except for not using microwave treatment, other conditions are the same as those in Example 2. The coking rate of the regenerated activated carbon is 6.1%, the adsorption saturation capacity is 32.7 g / kg, the adsorption performance recovery rate is 49%, and the energy consumption is 0.9 kWh / kg. The coking rate is significantly higher than that in Example 2, and the adsorption performance recovery rate is significantly lower than that in Example 2.

[0049] Comparative Example 5 S1. Mix the oil-containing activated carbon with a surfactant and then perform ultrasonic treatment to obtain the first oil-containing activated carbon. Specifically, the surfactant is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid, the ultrasonic frequency is 30 kHz, and the ultrasonic treatment time is 20 min. S2. Treat the first oil-containing activated carbon with microwave to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction. Specifically, the microwave power is 1.0 W / g, the temperature during microwave treatment is 80 °C, and the time is 10 min. S3. Extract the second oil-containing activated carbon with supercritical carbon dioxide to obtain regenerated activated carbon and the second oil fraction, and recover the second oil fraction. Specifically, the extraction temperature is 40 °C, the pressure is 8.5 MPa, and the time is 10 min. S4. Treat the regenerated activated carbon with ozone to obtain the second regenerated activated carbon. Specifically, the concentration of ozone is 100 ppm, and the ozone treatment time is 10 min.

[0050] In this comparative example, except for swapping the order of supercritical carbon dioxide extraction and microwave treatment, other conditions are the same as those in Example 2. The coking rate of the regenerated activated carbon is 14.8%, the adsorption saturation capacity is 30.1 g / kg, the adsorption performance recovery rate is 45%, and the energy consumption is 1.7 kWh / kg. The coking rate is significantly higher than that in Example 2, and the adsorption performance recovery rate is significantly lower than that in Example 2.

[0051] In the above examples, compared with the prior art, each step is carried out at a relatively low temperature, and the energy consumption in the whole process is also relatively low. After condition optimization, the coking rate and adsorption performance recovery rate of the regenerated activated carbon are relatively high.

[0052] The present application provides a method for regenerating oil-containing activated carbon, which has the following beneficial effects: the whole process adopts a low-temperature treatment process, avoiding the destruction of the activated carbon structure caused by high temperature, with a low coking rate and greatly saving energy; through supercritical carbon dioxide extraction and microwave desorption of oil, oil resource recovery is realized, and no harmful substances are generated during the process; adopting a multi-stage regeneration process can effectively desorb the oil in the oil-containing activated carbon, and after regeneration, the adsorption capacity recovery rate of the activated carbon is high and the energy consumption is low.

[0053] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural transformation made using the content of the specification of the present application under the inventive concept of the present application, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A method for regenerating oil-containing activated carbon, characterized in that, It includes the following steps: S1. After mixing the oil-containing activated carbon with a surfactant, perform ultrasonic treatment to obtain the first oil-containing activated carbon; S2. Use supercritical carbon dioxide to extract the first oil-containing activated carbon to obtain the second oil-containing activated carbon and the first oil fraction, and recover the first oil fraction; S3. Use microwave to treat the second oil-containing activated carbon to obtain the regenerated activated carbon and the second oil fraction, and recover the second oil fraction.

2. The regeneration method of an oil-containing activated carbon according to claim 1, wherein, After the step S3, it further includes: S4. Use ozone to treat the regenerated activated carbon to obtain the second regenerated activated carbon.

3. The regeneration method of an oil-containing activated carbon according to claim 1, characterized in that, In the step S1, the surfactant includes at least one of rhamnolipid or sophorolipid, and the mass of the surfactant is 0.02% - 0.2% of the mass of the oil-containing activated carbon.

4. A regeneration method of oil-containing activated carbon according to claim 1, characterized in that, In the step S1, the frequency of the ultrasonic wave is 20 - 50 kHz.

5. A regeneration method of oil-containing activated carbon according to claim 1, characterized in that, In the step S1, the time for performing the ultrasonic treatment is 10 - 60 min.

6. A regeneration method of oil-containing activated carbon according to claim 1, characterized in that, In the step S2, the temperature for extracting the first oil-containing activated carbon with the supercritical carbon dioxide is 35 - 60 °C, the pressure is 7.5 - 12 MPa, and the time is 5 - 30 min.

7. A regeneration method of oil-containing activated carbon according to claim 1, characterized in that, In the step S3, the power of the microwave is 0.5 - 2 W / g.

8. A regeneration method of oil-containing activated carbon according to claim 1, characterized in that, In the step S3, the temperature for treating the second oil-containing activated carbon with the microwave is 60 - 120 °C, and the time is 5 - 30 min.

9. A regeneration method of oil-containing activated carbon according to claim 2, characterized in that In the step S4, the concentration of the ozone is 50 - 300 ppm; the time for treating the regenerated activated carbon with the ozone is 5 - 30 min.

10. A regeneration method of oil-containing activated carbon according to claim 1, characterized in that, In the step S2, the first oil fraction includes organic substances with a molecular weight ≥ 200; in the step S3, the second oil fraction includes organic substances with a molecular weight < 200.