Method for preparing high-strength activated carbon particles by using waste activated carbon

Abstract

The invention belongs to the technical field of activated carbon thermal regeneration, and particularly relates to a method for preparing high-strength activated carbon particles by using waste activated carbon. According to the method, the waste activated carbon is subjected to high-temperature decomposition at the high temperature of 800-900 DEG C through water vapor activation, so that a carbonaceous material in the waste activated carbon is reactivated to generate a new pore structure, regeneration of the activated carbon is achieved, and the activated carbon has a high regeneration rate after ferric iron modified eggshell powder and kaolin powder are calcined; deionized water, sodium silicate, a defoaming agent and dodecanol polyoxyethylene ether are added to prepare the flue gas absorbent, and the flue gas absorbent has excellent adsorption and sulfur removal performance; the composite binder prepared by compounding coking coal oil, cross-linked starch and sodium silicate according to a certain proportion has good compatibility and wettability, promotes the activated carbon powder to form a firmer bonding structure, and improves the strength and adsorption capacity of activated carbon particles; the prepared surface modifier further improves the strength and wear resistance of the activated carbon particles and reduces the loss of the activated carbon.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon thermal regeneration, and in particular relates to a method for preparing high-strength activated carbon particles by utilizing waste activated carbon. Background Art

[0002] Activated carbon is a carbonaceous porous material with an amorphous structure of multi-layered ordered graphite microcrystals and irregular spatial lattices. Its internal pores are very developed, and various channels are interwoven. It can adsorb and treat multiple pollutants at the same time. As a good adsorption material, it has the advantages of low price, excellent adsorption performance, chemical stability and thermal stability. It is widely used in wastewater treatment, decolorization and purification, gas purification and other fields. After repeated use, the pore structure of activated carbon is blocked by adsorbents, and conventional desorption operations cannot restore it, resulting in a significant decrease or complete loss of adsorption capacity. Frequent replacement of waste activated carbon increases the environmental protection cost of the factory. As a rich body of toxic and harmful substances, waste activated carbon has the characteristics of flammability and toxicity. It needs to be treated to prevent pollutants from contacting the environment and causing pollution. At present, the main treatment methods for waste activated carbon are incineration and landfill. Incineration of waste activated carbon not only increases production costs, but also produces highly toxic byproducts such as dioxins, causing serious air pollution; landfilling of waste activated carbon will pollute the surrounding soil and water. Therefore, studying the regeneration method of waste activated carbon will help reduce the production cost of the factory, reduce the pollution problem of waste activated carbon and improve the resource utilization of carbon.

[0003] Regeneration of spent activated carbon refers to the technology of removing adsorbents from spent activated carbon by physical, chemical, physicochemical and other methods, restoring its adsorption properties, and obtaining activated carbon that can be used again. There are thermal regeneration, chemical regeneration and biological regeneration methods for spent activated carbon. At present, thermal regeneration is the most widely used method for regenerating spent activated carbon. It has the characteristics of high regeneration efficiency and easy industrial production. However, there are still problems such as high carbon loss rate, high energy consumption and low strength of thermally regenerated activated carbon that need to be solved.

[0004] The Chinese invention patent CN113620292B discloses a powdered activated carbon regeneration system and regeneration method. The powdered activated carbon regeneration system includes a drying tank, a carbonization tank and an activation device. The activation device includes a feeding mechanism, a heating mechanism and an exhaust gas treatment mechanism arranged in sequence. The heating mechanism includes a cylindrical activation furnace. The activation furnace is inclined relative to the horizontal plane. A concrete platform is arranged below the middle of the activation furnace. A gear ring drive mechanism is arranged on the concrete platform. The gear ring drive mechanism is sleeved on the outer side of the middle of the activation furnace. A heating cylinder is coaxially arranged inside the activation furnace, so that the activated carbon can be fully heated. However, the prior art has the technical problem that there is no further improvement in the activated carbon powder regeneration process to improve the strength and adsorption performance of activated carbon particles prepared by activated carbon powder. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing high-strength activated carbon particles using waste activated carbon, which is used to solve the technical problem that the prior art has not achieved the goal of improving the strength and adsorption performance of activated carbon particles prepared from activated carbon powder by further improving the activated carbon powder regeneration process.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The method for preparing high-strength activated carbon particles using waste activated carbon comprises the following steps: S1. Grind the waste activated carbon, pass it through a 100-200 mesh sieve to remove large impurities, wash it with water for 10-12 hours, and dry it at 100-150°C to obtain waste activated carbon powder; S2. The waste activated carbon powder is sent to the regeneration furnace, and water vapor is introduced. The temperature is raised to 800-900°C at a heating rate of 3-5°C / min, and the high-temperature decomposition is performed for 10-50s to obtain the regenerated activated carbon powder. The gas generated by the high-temperature decomposition is cooled to 250-300°C through an extremely cold tube, and then introduced into the absorption tower. The gas is controlled to pass through the flue gas absorbent at a flow rate of 1-3m / s, and the temperature is lowered to 150-200°C. The gas is washed with water and lowered to 50-70°C. The moisture is removed by a demister. After the pollutants in the gas are tested to meet the standards, the gas is discharged into the atmosphere. S3, after cooling the regenerated activated carbon powder to room temperature, grinding and screening, collecting large-size dust through a cyclone dust collector, and then collecting small-size dust through a bag dust collector; S4, mixing the regenerated activated carbon powder, the composite binder and deionized water, controlling the moisture content to 40-50wt%, to obtain a plastic carbon material; S5, extruding the plastic carbon material into granules through an extruder, pre-drying at 130-150°C for 0.5-1h, heating to 600-800°C at a heating rate of 3-5°C / min and carbonizing for 1-2h to obtain crude activated carbon granules; S6. Dissolve the surface modifier in deionized water, add crude activated carbon particles, soak for 10-12 hours, take out the crude activated carbon particles, and dry them at 100-150° C. to obtain high-strength activated carbon particles.

[0007] Preferably, the mass ratio of the waste activated carbon to deionized water in the water washing step in S1 is 1:4-6.

[0008] Preferably, the detection standard in S2 is that the sulfur dioxide content is less than 100 mg / m 3 , nitrogen oxides less than 200mg / m 3 .

[0009] Preferably, the operating parameters of the demisting machine in S2 are: inlet wind speed 2-5 m / s, blade spacing 30-50 mm, outlet gas droplet concentration 50-70 mg / Nm 3 .

[0010] Preferably, the grinding and screening passing standard in S3 is that more than 90 wt % of the regenerated activated carbon powder passes through an 80-100 mesh sieve.

[0011] Preferably, the operating parameters of the cyclone dust collector in S3 are an inlet wind speed of 20-25 m / s, and the operating parameters of the bag dust collector are a spraying pressure of 0.3-0.6 MPa, a spraying cycle of 30-90 s, and a spraying time of 0.1-1 s.

[0012] Preferably, the dust in S3 has a particle size larger than 5 μm and is considered large-particle dust, while the dust has a particle size smaller than 5 μm and is considered small-particle dust.

[0013] Preferably, the mass ratio of the regenerated activated carbon powder to the composite binder in S4 is 100:10-15.

[0014] Preferably, the extrusion temperature of the extruder in S5 is 130-150° C., and the average particle size of the particles produced by extrusion granulation is 1-4 mm.

[0015] Preferably, the ratio of the surface modifier to deionized water in S6 is 5-10 g: 500-1000 ml.

[0016] Preferably, the method for preparing the flue gas absorbent of S2 comprises the following steps: S11, after the eggshell powder and kaolin powder are evenly mixed, add to 5-10 g / L ferric chloride solution, adjust the solution pH to 9-10 with sodium carbonate, soak for 24-36 hours, filter and wash with deionized water, dry at 100-150 ° C, grind through a 100-200 mesh sieve to obtain a mixed solid; S12, calcining the mixed solid at 800-900° C. for 1-2 h to obtain an adsorption material; S13, mix 400-800 g of adsorption material, 15-20 g of sodium silicate, 1-5 g of defoaming agent and 1-5 g of polyoxyethylene dodecanol, add 1-2 L of deionized water and stir evenly to prepare a flue gas absorbent.

[0017] Preferably, the amount ratio of the eggshell powder, kaolin powder and ferric chloride solution in S11 is 100-500 g: 100-200 g: 1-2 L.

[0018] Preferably, the defoaming agent in S13 is any one or more combinations of polypropylene glycol ether, glycerol polyether and silicone defoaming agent.

[0019] Preferably, the method for preparing the composite binder of S4 comprises the following steps: S21, adding 250g corn starch to 800-1000ml deionized water, adjusting the pH to 8-9 with 5-10wt% sodium hydroxide solution, heating to 40-50°C, dropping 35-50g 30wt% hydrogen peroxide to react for 0.5-1h, heating to 80-95°C to react until the system becomes translucent, cooling to 70-80°C, dissolving 10-15g polyvinyl alcohol in 300-500ml deionized water and then dropping into the system, adding 3-5g sodium dihydrogen phosphate crosslinking agent to react for 1-2h, and drying to obtain cross-linked starch; S22. Put tar oil, cross-linked starch and sodium silicate into a mixer and stir at room temperature for 20 to 30 minutes to obtain a composite adhesive.

[0020] Preferably, the mass ratio of coke oil, cross-linked starch and sodium silicate in the S22 is 40-50:20-30:10-15.

[0021] Preferably, the preparation method of the surface modifier of S6 comprises the following steps: S31, adding 5-10 g of chitosan to 300-500 ml of deionized water, adjusting the pH to 3-4 with 1 wt % acetic acid solution, adding 2-hydroxy-4-methylbenzaldehyde and ethanol solution of oxadialdehyde, heating in a water bath to 70-80° C. for reaction for 6-12 h, and drying at 60° C. to obtain modified chitosan; S32. Add modified chitosan into polycaprolactone and nano-silica, and stir at 40-50° C. for 30 minutes to obtain a surface modifier.

[0022] Preferably, the mass ratio of chitosan, 2-hydroxy-4-methylbenzaldehyde and terpenoid in S31 is 5:0.2~0.5:0.5~1.

[0023] Preferably, the mass ratio of modified chitosan, polycaprolactone and nano-silicon dioxide in S32 is 5~7:2~3:0.2~0.5.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention optimizes the process of the prior art, first thermally regenerates waste activated carbon powder to obtain regenerated activated carbon powder, then bonds it with a binder, carbonizes it at high temperature and obtains high-strength activated carbon particles through surface modification, which have excellent adsorption, easy regeneration and mechanical properties.

[0025] 2. The present invention decomposes the waste activated carbon at 850°C through water vapor activation to convert it into water and carbon dioxide. The water vapor at high temperature reactivates the carbonaceous material in the waste activated carbon to generate a new pore structure, thereby achieving the regeneration of activated carbon with a high regeneration rate. The thermal decomposition time of activated carbon powder is greatly shortened, thereby improving energy utilization. The flue gas absorbent prepared by calcining eggshell powder and kaolin powder modified with trivalent iron and then adding deionized water, sodium silicate, defoaming agent and polyoxyethylene dodecanol has excellent adsorption and desulfurization performance, thereby ensuring the effective control and reuse of pollutants during the regeneration process.

[0026] 3. The composite binder prepared by compounding tar oil, cross-linked starch and sodium silicate in a certain proportion has good compatibility and wettability, promotes the activated carbon powder to form a more solid bonding structure, and improves the strength and adsorption capacity of the activated carbon particles; the corn starch is oxidized by hydrogen peroxide and then cross-linked with polyvinyl alcohol, and sodium dihydrogen phosphate can react with the hydroxyl groups in the oxidized starch and polyvinyl alcohol molecules to form a stable cross-linked structure. The prepared cross-linked starch has good bonding ability and can form a developed pore structure during the carbonization process, thereby improving the adsorption performance of the activated carbon particles.

[0027] 4. The present invention improves the solubility and adhesion of chitosan by modifying chitosan with 2-hydroxy-4-methylbenzaldehyde and oxadialdehyde. The modified chitosan, polycaprolactone and nano-silica are dissolved in deionized water in a certain proportion. The prepared surface modifier can further improve the strength and wear resistance of activated carbon particles and reduce the loss of activated carbon. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The waste activated carbon involved in the embodiment of the present invention is sulfur-containing waste activated carbon purchased from Fengzhen Yuanfengyu Pumice Mining Co., Ltd., and its element content is shown in the following Table 1: Table 1 Element content

[0030] Example 1: The method for preparing high-strength activated carbon particles using waste activated carbon in this example comprises the following steps: S1. Grind 1 kg of waste activated carbon, pass it through a 100-mesh sieve to remove large impurities, add it into 4 kg of deionized water, wash it for 10 hours, and dry it at 150°C to obtain waste activated carbon powder; S2. The waste activated carbon powder is sent to the regeneration furnace, steam is introduced, and the temperature is raised to 850°C at a heating rate of 5°C / min. The high-temperature decomposition is carried out for 10 seconds to obtain the regenerated activated carbon powder. The gas produced by the high-temperature decomposition is cooled to 250°C through an extremely cold tube and then introduced into the absorption tower. The gas is controlled to pass through the flue gas absorbent at a flow rate of 3m / s, and the temperature is reduced to 200°C. It is washed with water and cooled to 60°C. The moisture is removed by a defogger. The working parameters of the defogger are an inlet wind speed of 3m / s, a blade spacing of 30mm, and an outlet gas droplet concentration of 56mg / Nm 3 , after the pollutants in the detected gas meet the standards, they are discharged into the atmosphere; S3. After the regenerated activated carbon powder is cooled to room temperature, it is ground and passed through a 100-mesh sieve. After the large-size dust with a dust particle size greater than 5 μm is collected by a cyclone dust collector, the small-size dust is collected by a bag dust collector. The working parameters of the cyclone dust collector are an inlet wind speed of 20 m / s, and the working parameters of the bag dust collector are a blowing pressure of 0.3 MPa, a blowing cycle of 30 s, and a blowing time of 0.5 s. S4, mixing 1 kg of regenerated activated carbon powder, 100 g of composite binder and deionized water, controlling the moisture content to 40 wt %, to obtain a plastic carbon material; S5, extruding the plastic carbon material into granules through an extruder, the extrusion temperature is 130°C, the average particle size of the extruded granules is 1 mm, pre-drying at 150°C for 0.5h, heating to 800°C at a heating rate of 3°C / min for carbonization for 2h, and obtaining crude activated carbon granules; S6. Dissolve 10 g of the surface modifier in 500 mL of deionized water, add crude activated carbon particles, soak for 10 hours, take out the crude activated carbon particles, and dry them at 100° C. to obtain high-strength activated carbon particles.

[0031] The preparation method of the flue gas absorbent of this embodiment comprises the following steps: S11, after 100g of eggshell powder and 200g of kaolin powder are mixed evenly, add into 1L of 5g / L ferric chloride solution, adjust the solution pH to 9 with sodium carbonate, soak for 24h, filter and wash with deionized water, dry at 150°C, grind through a 100 mesh sieve to obtain a mixed solid; S12, calcining the mixed solid at 800° C. for 2 h to obtain an adsorbent material; S13, 400 g of the adsorption material, 15 g of sodium silicate, 3 g of PPG-10 and 3 g of polyoxyethylene lauryl alcohol ether were mixed, 1 L of deionized water was added and stirred evenly to prepare a flue gas absorbent.

[0032] The preparation method of the composite adhesive of this embodiment comprises the following steps: S21, adding 250g corn starch to 1000ml deionized water, adjusting the pH to 8.5 with 5wt% sodium hydroxide solution, heating to 50°C, adding 35g 30wt% hydrogen peroxide to react for 0.5h, heating to 95°C to react until the system becomes translucent, cooling to 80°C, dissolving 10g polyvinyl alcohol in 300ml deionized water and then adding dropwise to the system, adding 3g sodium dihydrogen phosphate crosslinking agent to react for 1h, and drying to obtain cross-linked starch; S22. Put 50 g of tar oil, 30 g of cross-linked starch, and 15 g of sodium silicate into a blender and stir at room temperature for 30 min to obtain a composite adhesive.

[0033] The preparation method of the surface modifier of this embodiment comprises the following steps: S31, adding 10g of chitosan to 500ml of deionized water, adjusting the pH to 3.5 with 1wt% acetic acid solution, adding 1g of 2-hydroxy-4-methylbenzaldehyde and 1g of oxadialdehyde to 100mL of ethanol to prepare a solution, then adding the chitosan solution, heating to 80°C in a water bath for 12h, and drying at 60°C to obtain modified chitosan; S32. Add 5 g of modified chitosan to 2 g of polycaprolactone and 0.2 g of nano-silicon dioxide, and stir at 50° C. for 30 min to obtain a surface modifier.

[0034] Embodiment 2: The method for preparing high-strength activated carbon particles using waste activated carbon in this embodiment comprises the following steps: S1. Grind 1 kg of waste activated carbon, pass it through a 150-mesh sieve to remove large impurities, add it into 5 kg of deionized water, wash it for 12 hours, and dry it at 100 ° C to obtain waste activated carbon powder; S2. The waste activated carbon powder is sent to the regeneration furnace, steam is introduced, and the temperature is raised to 800℃ at a heating rate of 3℃ / min. The high-temperature decomposition is carried out for 20s to obtain the regenerated activated carbon powder. The gas produced by the high-temperature decomposition is cooled to 260℃ through an extremely cold tube and then introduced into the absorption tower. The gas is controlled to pass through the flue gas absorbent at a flow rate of 2.5m / s, and the temperature is reduced to 180℃. It is washed with water and cooled to 70℃. The moisture is removed by a defogger. The working parameters of the defogger are an inlet wind speed of 4m / s, a blade spacing of 35mm, and an outlet gas droplet concentration of 53mg / Nm 3 , after the pollutants in the detected gas meet the standards, they are discharged into the atmosphere; S3. After the regenerated activated carbon powder is cooled to room temperature, it is ground and passed through an 80-mesh sieve. After the large-size dust with a dust particle size greater than 5 μm is collected by a cyclone dust collector, the small-size dust is collected by a bag dust collector. The working parameters of the cyclone dust collector are an inlet wind speed of 22 m / s, and the working parameters of the bag dust collector are a blowing pressure of 0.4 MPa, a blowing cycle of 50 s, and a blowing time of 0.2 s. S4, mixing 1 kg of regenerated activated carbon powder, 120 g of composite binder and deionized water, controlling the moisture content to 45 wt %, to obtain a plastic carbon material; S5, extruding the plastic carbon material into granules through an extruder, the extrusion temperature is 140°C, the average particle size of the extruded granules is 2.5 mm, pre-dried at 150°C for 1 hour, and then heated to 750°C at a heating rate of 3.5°C / min for carbonization for 1.5 hours to obtain crude activated carbon particles; S6. Dissolve 5 g of the surface modifier in 500 mL of deionized water, add crude activated carbon particles, soak for 12 hours, take out the crude activated carbon particles, and dry them at 120° C. to obtain high-strength activated carbon particles.

[0035] The preparation method of the flue gas absorbent of this embodiment is the same as the preparation method of embodiment 1.

[0036] The preparation method of the surface modifier of this embodiment is the same as the preparation method of Example 1.

[0037] The difference between the composite binder of this embodiment and that of Embodiment 1 is that the raw materials of the composite binder are replaced by 50 g of tar oil, 20 g of cross-linked starch and 10 g of sodium silicate.

[0038] Embodiment 3, the method for preparing high-strength activated carbon particles using waste activated carbon of this embodiment comprises the following steps: S1. Grind 1 kg of waste activated carbon, pass it through a 160-mesh sieve to remove large impurities, add it into 5.5 kg of deionized water, wash it for 12 hours, and dry it at 140°C to obtain waste activated carbon powder; S2. The waste activated carbon powder is sent to the regeneration furnace, steam is introduced, and the temperature is raised to 900℃ at a heating rate of 4℃ / min. The high-temperature decomposition is carried out for 10s to obtain the regenerated activated carbon powder. The gas produced by the high-temperature decomposition is cooled to 280℃ through an extremely cold tube and then introduced into the absorption tower. The gas is controlled to pass through the flue gas absorbent at a flow rate of 2.5m / s, and the temperature is reduced to 200℃. It is washed with water and cooled to 70℃. The moisture is removed by a defogger. The working parameters of the defogger are an inlet wind speed of 4m / s, a blade spacing of 40mm, and an outlet gas droplet concentration of 68mg / Nm 3 , after the pollutants in the detected gas meet the standards, they are discharged into the atmosphere; S3. After the regenerated activated carbon powder is cooled to room temperature, it is ground and sieved, passed through a 90-mesh sieve, and the large-size dust with a dust particle size greater than 5 μm is collected by a cyclone dust collector, and then the small-size dust is collected by a bag dust collector. The working parameters of the cyclone dust collector are an inlet wind speed of 23 m / s, and the working parameters of the bag dust collector are a blowing pressure of 0.5 MPa, a blowing cycle of 60 s, and a blowing time of 0.4 s; S4, mixing 1 kg of regenerated activated carbon powder, 140 g of a composite binder and deionized water, controlling the moisture content to 45 wt %, to obtain a plastic carbon material; S5, extruding the plastic carbon material into granules through an extruder, the extrusion temperature is 145°C, the average particle size of the extruded granules is 3.5 mm, pre-drying at 130°C for 0.5h, heating to 600°C at a heating rate of 5°C / min for carbonization for 2h, and obtaining crude activated carbon granules; S6. Dissolve 5 g of the surface modifier in 500 mL of deionized water, add crude activated carbon particles, soak for 10 hours, take out the crude activated carbon particles, and dry them at 150° C. to obtain high-strength activated carbon particles.

[0039] The preparation method of the composite adhesive of this embodiment is the same as the preparation method of embodiment 1.

[0040] The preparation method of the surface modifier of this embodiment is the same as the preparation method of Example 1.

[0041] The difference between the flue gas absorbent of this embodiment and that of Embodiment 1 is that the raw material dosage in the adsorbent material is replaced by 500 g of eggshell powder, 100 g of kaolin powder and 2 L of 10 g / L ferric chloride solution.

[0042] Example 4: The method for preparing high-strength activated carbon particles using waste activated carbon in this example comprises the following steps: S1. Grind 1 kg of waste activated carbon, pass it through a 200-mesh sieve to remove large impurities, add it into 6 kg of deionized water, wash it for 12 hours, and dry it at 150°C to obtain waste activated carbon powder; S2. The waste activated carbon powder is sent to the regeneration furnace, steam is introduced, and the temperature is raised to 900°C at a heating rate of 5°C / min. The high-temperature decomposition is carried out for 15s to obtain the regenerated activated carbon powder. The gas produced by the high-temperature decomposition is cooled to 250°C through an extremely cold tube and then introduced into the absorption tower. The gas is controlled to pass through the flue gas absorbent at a flow rate of 1m / s, and the temperature is reduced to 150°C. It is washed with water and cooled to 50°C. The moisture is removed by a defogger. The working parameters of the defogger are an inlet wind speed of 2m / s, a blade spacing of 50mm, and an outlet gas droplet concentration of 60mg / Nm 3 , after the pollutants in the detected gas meet the standards, they are discharged into the atmosphere; S3. After the regenerated activated carbon powder is cooled to room temperature, it is ground and sieved, passed through a 100-mesh sieve, and the large-size dust with a dust particle size greater than 5 μm is collected by a cyclone dust collector, and then the small-size dust is collected by a bag dust collector. The working parameters of the cyclone dust collector are an inlet wind speed of 25 m / s, and the working parameters of the bag dust collector are a blowing pressure of 0.6 MPa, a blowing cycle of 90 s, and a blowing time of 0.1 s; S4, mixing 1 kg of regenerated activated carbon powder, 150 g of composite binder and deionized water, controlling the moisture content to 50 wt %, to obtain a plastic carbon material; S5, extruding the plastic carbon material into granules through an extruder, the extrusion temperature is 150°C, the average particle size of the extruded granules is 4 mm, pre-drying at 150°C for 0.5 h, heating to 800°C at a heating rate of 3°C / min for carbonization for 2 h, and obtaining crude activated carbon granules; S6. Dissolve 5 g of the surface modifier in 1000 mL of deionized water, add crude activated carbon particles, soak for 12 hours, take out the crude activated carbon particles, and dry them at 100° C. to obtain high-strength activated carbon particles.

[0043] The preparation method of the flue gas absorbent of this embodiment is the same as the preparation method of embodiment 1.

[0044] The preparation method of the composite adhesive of this embodiment is the same as the preparation method of embodiment 1.

[0045] The difference between the surface modifier of this embodiment and that of embodiment 1 is that the raw material dosage of the surface modifier is replaced by 7 g of modified chitosan, 3 g of polycaprolactone and 0.5 g of nano-silicon dioxide.

[0046] Comparative Example 1: The difference between this comparative example and Example 1 is that the high temperature decomposition time of the waste activated carbon powder is replaced with 10 minutes.

[0047] Comparative Example 2: The difference between this comparative example and Example 1 is that the composite binder is replaced by coke oil.

[0048] Comparative Example 3: This comparative example differs from Example 1 in that the surface modifier is replaced by phenolic resin.

[0049] Performance Testing According to GB / T 7702-2008 “Test method for coal-based granular activated carbon”, the methylene blue adsorption capacity, iodine adsorption value, compressive strength and specific surface area of ​​the high-strength activated carbon particles prepared in each embodiment and comparative example were measured.

[0050] The test results are shown in Table 2 below: Table 2 Test results

[0051] It can be seen from the data in Table 2 above that the methylene blue adsorption of the high-strength activated carbon particles prepared in Examples 1 to 4 is between 119.5 and 126.4 mg / g, and the iodine adsorption value is between 813 and 834 mg / g. The composite binder in Comparative Example 2 is only coke oil, and the porosity of the activated carbon particles prepared by sintering and carbonizing is lower than that of the binder containing cross-linked starch. Therefore, its methylene blue adsorption and iodine adsorption value are slightly lower than the data of the activated carbon particles prepared in each embodiment, indicating that the high-strength activated carbon particles prepared in the present invention have excellent adsorption performance; Examples 1 to 4 prepared The compressive strength of the high-strength activated carbon particles is between 31.0 and 34.5 MPa, while the compressive strength of the activated carbon particles prepared in Comparative Example 1 is only 25.4 MPa, and the methylene blue adsorption amount is 103.9 mg / g and the iodine adsorption value is 705 mg / g, which are lower than those of the activated carbon particles prepared in each embodiment. This indicates that the high-temperature decomposition time of the waste activated carbon powder is too long, the high-temperature decomposition of the activated carbon powder is excessive, and the gaps of the carbon powder are broken and blocked, resulting in a decrease in its compressive strength and adsorption performance, further indicating that the high-strength activated carbon particles prepared in the present invention have excellent mechanical properties.

[0052] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0053] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing high-strength activated carbon particles using waste activated carbon, characterized in that: The steps include: S1. Grind the waste activated carbon, pass it through a 100-200 mesh sieve to remove large impurities, wash it with water for 10-12 hours, and dry it at 100-150°C to obtain waste activated carbon powder; S2. The waste activated carbon powder is sent to the regeneration furnace, and water vapor is introduced. The temperature is raised to 800-900°C at a heating rate of 3-5°C / min, and the high-temperature decomposition is performed for 10-50s to obtain the regenerated activated carbon powder. The gas generated by the high-temperature decomposition is cooled to 250-300°C through an extremely cold tube, and then introduced into the absorption tower. The gas is controlled to pass through the flue gas absorbent at a flow rate of 1-3m / s, and the temperature is lowered to 150-200°C. The gas is washed with water and lowered to 50-70°C. The moisture is removed by a demister. After the pollutants in the gas are tested to meet the standards, the gas is discharged into the atmosphere. S3, after cooling the regenerated activated carbon powder to room temperature, grinding and screening, collecting large-size dust through a cyclone dust collector, and then collecting small-size dust through a bag dust collector; S4, mixing the regenerated activated carbon powder, the composite binder and deionized water, controlling the moisture content to 40-50wt%, to obtain a plastic carbon material; S5, extruding the plastic carbon material into granules through an extruder, pre-drying at 130-150°C for 0.5-1h, heating to 600-800°C at a heating rate of 3-5°C / min and carbonizing for 1-2h to obtain crude activated carbon granules; S6. Dissolve the surface modifier in deionized water, add crude activated carbon particles, soak for 10-12 hours, take out the crude activated carbon particles, and dry them at 100-150° C. to obtain high-strength activated carbon particles.

2. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 1, characterized in that: The method for preparing the flue gas absorbent of S2 comprises the following steps: S11, after the eggshell powder and kaolin powder are evenly mixed, add to 5-10 g / L ferric chloride solution, adjust the solution pH to 9-10 with sodium carbonate, soak for 24-36 hours, filter and wash with deionized water, dry at 100-150 ° C, grind through a 100-200 mesh sieve to obtain a mixed solid; S12, calcining the mixed solid at 800-900° C. for 1-2 h to obtain an adsorption material; S13, mix 400-800 g of adsorption material, 15-20 g of sodium silicate, 1-5 g of defoaming agent and 1-5 g of polyoxyethylene dodecanol, add 1-2 L of deionized water and stir evenly to prepare a flue gas absorbent.

3. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 2, characterized in that: The amount ratio of eggshell powder, kaolin powder and ferric chloride solution in S11 is 100-500g: 100-200g: 1-2L; the defoaming agent in S13 is any one or more combinations of polypropylene glycol ether, glycerol polyether and silicone defoaming agent.

4. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 1, characterized in that: The preparation method of the composite binder of S4 comprises the following steps: S21, adding 250g corn starch to 800-1000ml deionized water, adjusting the pH to 8-9 with 5-10wt% sodium hydroxide solution, heating to 40-50°C, dropping 35-50g 30wt% hydrogen peroxide to react for 0.5-1h, heating to 80-95°C to react until the system becomes translucent, cooling to 70-80°C, dissolving 10-15g polyvinyl alcohol in 300-500ml deionized water and then dropping into the system, adding 3-5g sodium dihydrogen phosphate crosslinking agent to react for 1-2h, and drying to obtain cross-linked starch; S22. Put tar oil, cross-linked starch and sodium silicate into a mixer and stir at room temperature for 20 to 30 minutes to obtain a composite adhesive.

5. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 4, characterized in that: The mass ratio of coke oil, cross-linked starch and sodium silicate in the S22 is 40-50:20-30:10-15.

6. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 1, characterized in that: The preparation method of the surface modifier of S6 comprises the following steps: S31, adding 5-10 g of chitosan to 300-500 ml of deionized water, adjusting the pH to 3-4 with 1 wt % acetic acid solution, adding 2-hydroxy-4-methylbenzaldehyde and ethanol solution of oxadialdehyde, heating in a water bath to 70-80° C. for reaction for 6-12 h, and drying at 60° C. to obtain modified chitosan; S32. Add modified chitosan into polycaprolactone and nano-silica, and stir at 40-50° C. for 30 minutes to obtain a surface modifier.

7. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 6, characterized in that: The mass ratio of chitosan, 2-hydroxy-4-methylbenzaldehyde and oxadialdehyde in S31 is 5:0.2~0.5:0.5~1; the mass ratio of modified chitosan, polycaprolactone and nano-silicon dioxide in S32 is 5~7:2~3:0.2~0.

5.

8. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 1, characterized in that: The mass ratio of the waste activated carbon to deionized water in the washing step in S1 is 1:4-6; the detection standard in S2 is that the sulfur dioxide content is less than 100 mg / m 3 , nitrogen oxides less than 200mg / m 3 The working parameters of the defogger are inlet wind speed 2~5m / s, blade spacing 30~50mm, and outlet gas droplet concentration 50~70mg / Nm 3 ; The grinding and screening standard in S3 is that more than 90wt% of the regenerated activated carbon powder passes through an 80-100 mesh sieve, the working parameters of the cyclone dust collector are an inlet wind speed of 20-25m / s, the working parameters of the bag dust collector are a spraying pressure of 0.3-0.6MPa, a spraying cycle of 30-90s, a spraying time of 0.1-1s, and dust particles with a size greater than 5μm are large-particle dust, and dust particles with a size less than 5μm are small-particle dust.

9. The method for preparing high-strength activated carbon particles using waste activated carbon according to claim 1, characterized in that: The mass ratio of the regenerated activated carbon powder to the composite binder in S4 is 100:10-15; the extrusion temperature of the extruder in S5 is 130-150°C, and the average particle size of the extruded granulated particles is 1-4 mm; the ratio of the surface modifier to deionized water in S6 is 5-10 g: 500-1000 ml.

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