A regeneration method for oil-containing activated carbon

Abstract

The present application belongs to the technical field of regeneration of oil-containing activated carbon, specifically a method for regenerating oil-containing activated carbon, comprising the following steps: 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; 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; treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil component, and recovering the second oil component. The method of the present application adopts a low-temperature treatment process throughout the entire process to avoid high temperature-induced structural damage to the activated carbon, resulting in a low coking rate and significant energy savings; oil resource recovery is achieved through supercritical carbon dioxide extraction and microwave desorption of the oil component, and no harmful substances are generated during the process; a multi-stage regeneration process can effectively desorb the oil in the oil-containing activated carbon, and the activated carbon adsorption capacity recovery rate after regeneration is high, with low energy consumption.

Description

Technical Field

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

[0002] The wastewater (raffinate) generated after product recovery during extraction processes in the hydrometallurgical industry often contains oil. Direct MVR evaporation without treatment not only reduces evaporation efficiency and damages equipment, but also consumes a lot of energy and produces low-purity byproduct salts. The oil content in the raffinate is primarily composed of phosphate extractants (P204, P507, CY272), No. 260 solvent oil, and its decomposition products. Common treatment methods involve adsorption removal with materials such as degreasing resins and activated carbon. Activated carbon, in particular, is widely used due to its strong adsorption capacity, high adsorption capacity, and rapid adsorption rate. After saturation, activated carbon is regenerated through high-temperature thermal regeneration, chemical regeneration, or microbial regeneration to desorb the oil and produce regenerated activated carbon. However, these methods suffer from a number of drawbacks, including high energy consumption, high activated carbon burnout rates, large chemical reagent volumes, long processing times, and decreased adsorption capacity after regeneration. Therefore, the development of novel regeneration technologies for oil-containing activated carbon is urgently needed.

[0003] Patent CN111889090A discloses a method for regenerating activated carbon through high-temperature pyrolysis. This method uses carboxylated ionic liquids and sodium salts as activated carbon regeneration aids, followed by high-temperature carbonization and steam activation to produce the regenerated activated carbon. This method consumes a lot of energy and results in significant activated carbon loss.

[0004] Patent CN115970666A discloses an activated carbon regeneration process that uses ultrasonic agitation, acid washing, residual acid removal, high-temperature carbonization, and activation to produce regenerated activated carbon. This method also consumes a lot of energy and is prone to producing toxic gases.

[0005] Patent CN119186539A discloses an activated carbon regeneration method based on ultrasonic coupling. This method uses temperature-controlled ultrasonic vibrations to adjust the pH of the reaction solution to regenerate the activated carbon. However, this method has low activated carbon regeneration efficiency and consumes chemical reagents such as acids and bases.

[0006] Patent CN118874448A discloses a method for regenerating waste activated carbon, which uses microwave high-temperature heating and desorption technology to regenerate activated carbon. This method has poor practical effects and poor desorption effect.

[0007] Patent KR20230040647A discloses a method for graded regeneration of activated carbon using ozone and supercritical carbon dioxide. In this method, both ozone and supercritical carbon dioxide are fed into the same regeneration reactor to treat the activated carbon. Because ozone and high-pressure carbon dioxide react to produce atomic oxygen, the reaction vessel must be constructed of high-pressure and corrosion-resistant materials, significantly increasing costs and posing safety risks. Summary of the Invention

[0008] In response to 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] The present invention provides a method for regenerating oil-containing activated carbon, comprising the following steps:

[0010] S1, mixing the oil-containing activated carbon with a surfactant, and performing ultrasonic treatment to obtain a first oil-containing activated carbon;

[0011] S2. extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil;

[0012] 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.

[0013] In the above technical solution, 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 existence of the oil film and the surface binding layer will lead to a decrease in the effect of the subsequent treatment process, which is disadvantageous in terms of performance and cost; the heavy oil (first oil) with high boiling point, large molecules and high viscosity in the oil-containing activated carbon usually needs to be dissolved at low temperature and high pressure, while supercritical fluid Carbon dioxide can efficiently dissolve non-polar heavy oil, and the reaction conditions meet the requirements. Therefore, 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 the molecules, while the temperature of the activated carbon skeleton rises slowly, selectively separating the oil and water from the activated carbon. In addition, the microwave electric field changes the molecular energy level, weakening 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 the light oil (second oil) with low boiling point, small molecules and low viscosity.

[0014] The reasons for using supercritical carbon dioxide extraction followed by microwave treatment are as follows: 1. Avoid coking. The microwave reaction temperature is relatively high. If microwave heating treatment is performed first, the heavy oil will carbonize and coke, blocking the pores of the activated carbon; 2. Improve the purity of oil recovery. Supercritical carbon dioxide preferentially extracts heavy oil. The purity of the recovered heavy oil is >90%, with almost no light oil mixed in. Microwave treatment recovers light oil components by heating and condensing, with a purity >85%, thereby achieving graded utilization of light and heavy oils; 3. Reduce energy consumption. The supercritical carbon dioxide extraction reaction conditions are at low temperatures, while the temperature required for microwave treatment is relatively high. The low-temperature removal of heavy oil and high-temperature removal of light oil technical route is adopted. Microwaves only need to process a small amount of residual light oil, and the overall energy consumption is lower; 4. Increase safety. If microwave treatment is performed first, the coke produced will block the high-pressure pipeline, and the risk factor increases under high temperature and high pressure conditions.

[0015] Furthermore, after step S3, the method further includes:

[0016] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon.

[0017] In step S4, ozone decomposition generates free radicals that attack the oil molecules, destroying their bonds and causing oil decomposition. This aims to decompose the small amount of organic matter remaining in the regenerated activated carbon, repair the activated carbon's specific surface area, and further restore the adsorption properties of the regenerated activated carbon. Placing this step after supercritical carbon dioxide extraction and microwave treatment can reduce costs, improve safety, and enhance reaction efficiency.

[0018] Further, in step S1, the surfactant includes at least one of rhamnolipid or sophorolipid, and the mass of the surfactant is 0.02% to 0.2% of the mass of the oil-containing activated carbon; the preferred dosage is 0.1% rhamnolipid and 0.05% sophorolipid mixed, and further increasing the dosage will hardly improve the effect and waste reagents.

[0019] Furthermore, in step S1, the frequency of the ultrasonic wave is 20-50 kHz.

[0020] Furthermore, in step S1, the ultrasonic treatment is performed for 10 to 60 minutes.

[0021] Furthermore, in step S2, the first oil-containing activated carbon is extracted with supercritical carbon dioxide at a temperature of 35-60°C, a pressure of 7.5-12 MPa, and a time of 5-30 min.

[0022] Furthermore, in step S3, the power of the microwave is 0.5-2 W / g.

[0023] Furthermore, in step S3, the second oil-containing activated carbon is treated with microwaves at a temperature of 60-120° C. for 5-30 minutes.

[0024] Furthermore, in step S4, the concentration of ozone is 50-300 ppm; and the time for treating the regenerated activated carbon with ozone is 5-30 minutes.

[0025] Furthermore, in step S2, the first oil comprises organic matter with a molecular weight of ≥200; and in step S3, the second oil comprises organic matter with a molecular weight of <200.

[0026] The present application proposes a regeneration method for oil-containing activated carbon, which produces the following beneficial effects: a low-temperature treatment process is adopted throughout the entire process to avoid damage to the activated carbon structure caused by high temperature, resulting in a low coking rate and great energy savings; oil resources are recovered through supercritical carbon dioxide extraction and microwave desorption of oil, and no harmful substances are produced in the process; a multi-stage regeneration process is adopted to effectively desorb the oil in the oil-containing activated carbon, and the activated carbon adsorption capacity recovery rate after regeneration is high and the energy consumption is low. DETAILED DESCRIPTION

[0027] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] The technical solution proposed in this application includes the following steps:

[0029] S1, mixing the oil-containing activated carbon with a surfactant, and performing ultrasonic treatment to obtain a first oil-containing activated carbon;

[0030] Specifically, the adsorption capacity of the oil-containing activated carbon is ≤66.8 g / kg, the surfactant used includes at least one of rhamnolipid or sophorolipid, the mass of which is 0.02%~0.2% of the mass of the oil-containing activated carbon, and the preferred amount is a mixture of 0.1% rhamnolipid and 0.05% sophorolipid; the frequency of the ultrasound is 20~50 kHz, and the time for ultrasonic treatment is 10~60 min; the specific frequency of the ultrasound is any one of 20 kHz, 30 kHz, 40 kHz, 50 kHz or the range between any two, and the time for ultrasonic treatment is any one of 10 min, 20 min, 30 min, 40 min, 50 min, 60 min or the range between any two.

[0031] S2. extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil;

[0032] Specifically, the first oil component includes organic matter with a molecular weight ≥200, the extraction temperature is 35~60°C, the pressure is 7.5~12MPa, and the time is 5~30min; specifically, the extraction temperature is any one of 35°C, 40°C, 45°C, 50°C, 55°C, and 60°C, or in a range between any two of them, the extraction pressure is any one of 7.5MPa, 8.5MPa, 9.5MPa, 10.5MPa, 11.5MPa, and 12MPa, or in a range between any two of them, and the extraction time is any one of 5min, 15min, 25min, and 30min, or in a range between any two of them.

[0033] S3, treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil;

[0034] Specifically, the second oil component includes an organic matter with a molecular weight of less than 200, the microwave power is 0.5-2 W / g, the temperature during microwave treatment is 60-120° C., and the time is 5-30 min. Specifically, the microwave power is any one of 0.5 W / g, 1.0 W / g, 1.5 W / g, and 2.0 W / g, or in a range between any two of them, the temperature during microwave treatment is any one of 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., and 120° C., or in a range between any two of them, and the microwave treatment time is any one of 5 min, 15 min, 25 min, and 30 min, or in a range between any two of them.

[0035] In order to further restore the adsorption performance of the regenerated activated carbon, the following steps are further included after step S3:

[0036] S4, treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon;

[0037] Specifically, the ozone concentration is 50~300ppm, and the ozone treatment time is 5~30min. Specifically, the ozone concentration is any one of 50ppm, 100ppm, 150ppm, 200ppm, 250ppm, 300ppm or a range between any two of them, and the ozone treatment time is any one of 5min, 15min, 25min, 30min or a range between any two of them.

[0038] The technical solution of this application is further described below with reference to specific embodiments.

[0039] The activated carbon used in each embodiment and comparative example is all adsorption-saturated oil-containing activated carbon, and its saturated adsorption capacity is 66.8 g / kg.

[0040] Example 1

[0041] A method for regenerating oil-containing activated carbon comprises the following steps:

[0042] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 20 min;

[0043] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 40° C., the pressure is 8.5 MPa, and the time is 10 min;

[0044] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 1.0 W / g, the microwave treatment temperature is 80° C., and the treatment time is 10 min;

[0045] In order to further verify the effect of regenerated activated carbon, the regenerated activated carbon of Example 1 was used to conduct an oil adsorption experiment, and its coking rate was found to be 4.7%, the adsorption saturation capacity was 46.1 g / kg, the adsorption performance recovery rate was 69%, and the energy consumption was 0.8 kWh / kg.

[0046] Example 2

[0047] A method for regenerating oil-containing activated carbon comprises the following steps:

[0048] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 20 min;

[0049] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 40° C., the pressure is 8.5 MPa, and the time is 10 min;

[0050] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 1.0 W / g, the microwave treatment temperature is 80° C., and the treatment time is 10 min;

[0051] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0052] In order to further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon of Example 2 was used to conduct an oil adsorption experiment, and the result showed that its coking rate was 1.3%, the adsorption saturation capacity was 61.5 g / kg, the adsorption performance recovery rate was 92%, and the energy consumption was 1.1 kWh / kg.

[0053] Example 3

[0054] A method for regenerating oil-containing activated carbon comprises the following steps:

[0055] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 10 min;

[0056] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 35° C., the pressure is 7.5 MPa, and the extraction time is 5 min;

[0057] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 0.5 W / g, the microwave treatment temperature is 60° C., and the treatment time is 5 min;

[0058] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 50 ppm, and the ozone treatment time is 5 minutes.

[0059] In order to further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon of Example 3 was used to conduct an oil adsorption experiment, and the result showed that its coking rate was 0.5%, the adsorption saturation capacity was 32.1 g / kg, the adsorption performance recovery rate was 48%, and the energy consumption was 0.9 kWh / kg.

[0060] Example 4

[0061] A method for regenerating oil-containing activated carbon comprises the following steps:

[0062] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 60 min;

[0063] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 60° C., the pressure is 12 MPa, and the time is 30 min;

[0064] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 2 W / g, the microwave treatment temperature is 120° C., and the treatment time is 30 min;

[0065] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 300 ppm, and the ozone treatment time is 30 minutes.

[0066] In order to further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon of Example 4 was used to conduct an oil adsorption experiment, and the result showed that its coking rate was 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.

[0067] Example 5

[0068] A method for regenerating oil-containing activated carbon comprises the following steps:

[0069] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 30 min;

[0070] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 60° C., the pressure is 7.5 MPa, and the time is 10 min;

[0071] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 1.5 W / g, the temperature during microwave treatment is 120° C., and the time is 10 min;

[0072] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0073] In order to further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon of Example 5 was used to conduct an oil adsorption experiment, and the result showed that its coking rate was 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.

[0074] Example 6

[0075] A method for regenerating oil-containing activated carbon comprises the following steps:

[0076] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 20 min;

[0077] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 40° C., the pressure is 8.5 MPa, and the time is 10 min;

[0078] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 1.5 W / g, the temperature during microwave treatment is 120° C., and the time is 10 min;

[0079] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0080] In order to further verify the effect of the second regenerated activated carbon, the second regenerated activated carbon of Example 6 was used to conduct an oil adsorption experiment, and the result showed that 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.

[0081] Comparative Example 1

[0082] A method for regenerating oil-containing activated carbon comprises the following steps:

[0083] S1. The oil-containing activated carbon is directly subjected to ultrasonic treatment to obtain a first oil-containing activated carbon; specifically, the ultrasonic frequency is 20 kHz, and the ultrasonic treatment time is 10 min;

[0084] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 35° C., the pressure is 7.5 MPa, and the extraction time is 5 min;

[0085] S3. Treating the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the microwave power is 0.5 W / g, the microwave treatment temperature is 60° C., and the treatment time is 5 min;

[0086] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 50 ppm, and the ozone treatment time is 5 minutes.

[0087] This comparative example is consistent with Example 3 except that no surfactant is used. The coking rate of the second regenerated activated carbon is 0.7%, the adsorption saturation capacity is 23.4 g / kg, the adsorption performance recovery rate is 35%, and the energy consumption is 0.9 kWh / kg. The adsorption performance recovery rate is lower than that of Example 3.

[0088] Comparative Example 2

[0089] A method for regenerating oil-containing activated carbon comprises the following steps:

[0090] S1. Extracting the oil-containing activated carbon with supercritical carbon dioxide to obtain a first oil-containing activated carbon and a first oil fraction, and recovering the first oil fraction; specifically, the extraction temperature is 40° C., the pressure is 8.5 MPa, and the extraction time is 10 min;

[0091] S3. Treating the first oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil fraction, and recovering the second oil fraction; specifically, the microwave power is 1.0 W / g, the microwave treatment temperature is 80° C., and the treatment time is 10 min;

[0092] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0093] This comparative example is consistent with Example 2 except that no surfactant is used and no ultrasonic treatment is performed. The second regenerated activated carbon coking rate is 1.2%, the adsorption saturation capacity is 46.1 g / kg, the adsorption performance recovery rate is 69%, and the energy consumption is 1.0 kWh / kg. The adsorption performance recovery rate is significantly lower than that of Example 2.

[0094] Comparative Example 3

[0095] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 20 min;

[0096] S2. treating the first oil-containing activated carbon with microwaves to obtain regenerated activated carbon; specifically, the microwave power is 1.0 W / g, the temperature during microwave treatment is 80° C., and the time is 10 min;

[0097] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0098] Except for not using supercritical carbon dioxide extraction, this comparative example is consistent with 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%, and the energy consumption is 1.0 kWh / kg. The coking rate is significantly higher than that of Example 2, and the adsorption performance recovery rate is significantly lower than that of Example 2.

[0099] Comparative Example 4

[0100] A method for regenerating oil-containing activated carbon comprises the following steps:

[0101] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 20 min;

[0102] S2. Extracting the first oil-containing activated carbon with supercritical carbon dioxide to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the extraction temperature is 40° C., the pressure is 8.5 MPa, and the time is 10 min;

[0103] S3. Treat the second oil-containing activated carbon with ozone to obtain regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0104] This comparative example is consistent with Example 2 except that microwave treatment is not used. 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 of Example 2, and the adsorption performance recovery rate is significantly lower than that of Example 2.

[0105] Comparative Example 5

[0106] S1. After mixing the oil-containing activated carbon with a surfactant, ultrasonic treatment is performed to obtain a 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 ultrasonic treatment time is 20 min;

[0107] S2. treating the first oil-containing activated carbon with microwaves to obtain a second oil-containing activated carbon and the first oil, and recovering the first oil; specifically, the microwave power is 1.0 W / g, the temperature during the microwave treatment is 80° C., and the time is 10 min;

[0108] S3. Extracting the second oil-containing activated carbon with supercritical carbon dioxide to obtain regenerated activated carbon and a second oil, and recovering the second oil; specifically, the extraction temperature is 40° C., the pressure is 8.5 MPa, and the extraction time is 10 min;

[0109] S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon; specifically, the ozone concentration is 100 ppm, and the ozone treatment time is 10 minutes.

[0110] In this comparative example, except for reversing the order of supercritical carbon dioxide extraction and microwave treatment, the rest is consistent with Example 2. The regenerated activated carbon has a coking rate of 14.8%, an adsorption saturation capacity of 30.1 g / kg, an adsorption performance recovery rate of 45%, and an energy consumption of 1.7 kWh / kg. The coking rate is significantly higher than that of Example 2, and the adsorption performance recovery rate is significantly lower than that of Example 2.

[0111] Compared with the prior art, each step in the above embodiment is carried out at a lower temperature, and the energy consumption in the entire process is also lower. After the conditions are optimized, the coking rate and adsorption performance recovery rate of the regenerated activated carbon are relatively high.

[0112] The present application proposes a regeneration method for oil-containing activated carbon, which produces the following beneficial effects: a low-temperature treatment process is adopted throughout the entire process to avoid damage to the activated carbon structure caused by high temperature, resulting in a low coking rate and great energy savings; oil resources are recovered through supercritical carbon dioxide extraction and microwave desorption of oil, and no harmful substances are produced in the process; a multi-stage regeneration process is adopted to effectively desorb the oil in the oil-containing activated carbon, and the activated carbon adsorption capacity recovery rate after regeneration is high and the energy consumption is low.

[0113] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for regenerating oil-containing activated carbon, characterized in that: The following steps are involved: S1, mixing the oil-containing activated carbon with a surfactant, and performing 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, and recovering the first oil; extracting the first oil-containing activated carbon with supercritical carbon dioxide at a temperature of 35-60° C. and a pressure of 7.5-12 MPa; S3. Treat the second oil-containing activated carbon with microwaves to obtain regenerated activated carbon and a second oil, and recover the second oil; the power of the microwaves is 0.5-2 W / g, and the temperature for treating the second oil-containing activated carbon with microwaves is 60-120° C.

2. The regeneration method of oil-containing activated carbon according to claim 1, characterized in that: After step S3, the method further includes: S4. Treating the regenerated activated carbon with ozone to obtain second regenerated activated carbon.

3. The regeneration method of 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% to 0.2% of the mass of the oil-containing activated carbon.

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

5. The regeneration method of oil-containing activated carbon according to claim 1, characterized in that: In step S1, the ultrasonic treatment is performed for 10 to 60 minutes.

6. The method for regenerating oil-containing activated carbon according to claim 1, characterized in that: In step S2, the time for extracting the first oil-containing activated carbon with the supercritical carbon dioxide is 5 to 30 minutes.

7. The regeneration method of oil-containing activated carbon according to claim 1, characterized in that: In the step S3, the second oil-containing activated carbon is treated with the microwave for 5 to 30 minutes.

8. The method for regenerating oil-containing activated carbon according to claim 2, characterized in that: In step S4, the concentration of the ozone is 50-300 ppm; and the time for treating the regenerated activated carbon with the ozone is 5-30 minutes.

9. The method for regenerating oil-containing activated carbon according to claim 1, characterized in that: In the step S2, the first oil comprises organic matter with a molecular weight of ≥200; and in the step S3, the second oil comprises organic matter with a molecular weight of <200.