阅读说明：本技术 一种废旧活性炭再生工艺 (Waste activated carbon regeneration process ) 是由 董杰 陈安江 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种废旧活性炭再生工艺,涉及环保化工领域,该工艺采用药剂洗脱方法再生废旧活性炭,在再生液浸泡过程中,一方面添加超声波发声装置,利用超声波间接震荡增强再生液进入活性炭内部孔隙中。另一方面利用氮气冷却-间接抽真空法所产生的压差将再生液充分扩充且反复侵入至活性炭较深的内部空隙中,能够大幅改善药剂洗脱不彻底现象。此外在洗脱结束烘干后,再次使用蒸馏水辅以超声波震荡浸泡活性炭,冷冻使液态水变为体积较大的固态冰扩增活性炭内部孔隙,通过真空冷冻干燥,使活性炭在最大限度地保持活性炭多孔蓬松结构的情况下去除水分。采用本发明工艺再生的活性炭,保留了药剂洗脱炭损率低的优点,同时大幅改善废旧活性炭内部浸泡洗脱不彻底现象,增大了废旧活性炭的内部空隙,提高废旧活性炭的再生效果。(The invention discloses a waste activated carbon regeneration process, which relates to the field of environmental protection chemical industry. On the other hand, the pressure difference generated by the nitrogen cooling-indirect vacuum pumping method is utilized to fully expand the regeneration liquid and repeatedly invade the deeper inner gap of the active carbon, so that the phenomenon of incomplete medicament elution can be greatly improved. And after the elution is finished and the drying is finished, soaking the activated carbon by using distilled water and ultrasonic oscillation again, freezing to change liquid water into solid ice with larger volume to expand the internal pores of the activated carbon, and removing water from the activated carbon under the condition of keeping the porous fluffy structure of the activated carbon to the maximum extent by vacuum freeze drying. The activated carbon regenerated by the process disclosed by the invention retains the advantage of low loss rate of the medicament elution carbon, greatly improves the phenomenon that the inside of the waste activated carbon is not thoroughly soaked and eluted, enlarges the internal gaps of the waste activated carbon, and improves the regeneration effect of the waste activated carbon.)

1. A waste activated carbon regeneration process is characterized by comprising the following steps:

A. pretreatment: cleaning the waste activated carbon with a distilled water solution, freezing to change liquid phase water in the waste activated carbon into solid water, and then placing the solid water in a vacuum freeze dryer for drying and dewatering;

B. soaking and eluting the regeneration solution: placing the waste activated carbon which is freeze-dried and dehydrated in the step A into a reaction kettle, introducing a regeneration liquid for soaking, wherein the soaking temperature is set to be 20-40 ℃, and the soaking elution time is 6-12 hours; meanwhile, a plurality of ultrasonic wave generating devices are arranged in the reaction kettle, the ultrasonic wave generators are started at intervals, the interval time is 40-60min each time, and the duration time of each time of sound wave action is 30-45 min; in the elution process, introducing nitrogen into the reaction kettle from top to bottom, vacuumizing the reaction kettle, and expanding the speed and the content of the regenerated liquid passing through the aperture by adopting a nitrogen cooling-vacuumizing method; the nitrogen cooling-vacuumizing is intermittently started and the ultrasonic vibration is alternately started. The interval time is 30-45min each time, and the continuous vacuum pumping time is 40-60 min;

C. recovering and replacing the regenerated liquid: replacing the regeneration liquid every 3-4h of soaking, inputting the waste regeneration liquid into a distillation device according to the boiling point of the solvent, and introducing the cooled and recovered regeneration liquid into the reaction kettle again, wherein the replacement times of the regeneration liquid are 2-4 times;

D. washing: washing the waste activated carbon soaked and eluted in the step C by using an ethanol solution with the concentration of 95%, and then washing the waste activated carbon to be in a neutral state by using distilled water;

E. drying: placing the activated carbon washed to be neutral in the step C in a rotary furnace for drying, wherein the drying temperature is 100-200 ℃; the heating speed is set to be 5-10 ℃/min, and the drying time is 6-10 h;

F. e, putting the dried sample in the reaction kettle again, introducing distilled water to soak for 1-2h, and simultaneously continuously oscillating the ultrasonic device to ensure that the distilled water fully enters the activated carbon channel; rapidly introducing nitrogen for freezing, completely freezing, and drying and dehydrating in a vacuum freeze dryer at-40 to-50 ℃ to obtain a finished product, wherein the freeze drying time is set to be 10-16 h;

G. tail gas treatment: and E, discharging the tail gas after the tail gas treatment reaches the standard.

2. The waste activated carbon regeneration process according to claim 1, characterized in that: the ratio of the regeneration liquid to the waste activated carbon is 1.5:1, the temperature of the regeneration liquid is 25 ℃, and the soaking and elution time is 9 hours.

3. The waste activated carbon regeneration process according to claim 1, characterized in that: the ultrasonic wave generating device is two ultrasonic generators with different frequencies, and each ultrasonic generator is at least provided with two groups of vibrators.

4. The waste activated carbon regeneration process according to claim 3, characterized in that: the ultrasonic generator is a double-frequency combination of 45KHz and 80 KHz.

5. The waste activated carbon regeneration process according to claim 3, characterized in that: the interval time of the ultrasonic generator starting is 60min, and the duration time of each sound wave action is 40 min.

6. The waste activated carbon regeneration process according to claim 3, characterized in that: the interval time of the nitrogen cooling-vacuumizing method is 40min, and the duration time of each vacuumizing is 60 min.

7. The waste activated carbon regeneration process according to claim 1, characterized in that: and C, setting the temperature of the freeze dryer in the step A and the temperature of the freeze dryer in the step F to be-50 ℃ and setting the drying time to be 12 h.

8. The waste activated carbon regeneration process according to claim 2, characterized in that: the organic solvent regeneration liquid is sodium hydroxide, potassium hydroxide, methanol, ethanol, isopropanol or acetone.

Technical Field

The invention relates to the field of environmental protection chemical industry, in particular to a waste activated carbon regeneration process.

Background

The active carbon is used as a high-quality adsorption material, the good adsorption performance of the active carbon is determined by the rich pore structure and the huge specific surface area of the active carbon, and the active carbon has the characteristics of good strength and difficult corrosion by substances such as acid, alkali and the like and is widely applied to various industries. For example, in food decolorization, environmental protection treatment of sewage, gas masks, daily and civil activated carbon masks, household water purifiers and the like, a large amount of activated carbon is required as a main adsorbent. However, with the increasing use amount of the activated carbon, the problem of activated carbon regeneration comes along with the increase of the use amount of the activated carbon, the unit price of the activated carbon is high, the resource is limited, if the activated carbon is not recycled after being used once, huge cost and resource waste are caused, and meanwhile, the problem of secondary pollution is also caused. Therefore, the regeneration method and process optimization of the waste activated carbon in recent years are also called a problem which is solved to the utmost extent by various industries.

The existing regeneration method of activated carbon with saturated adsorption mainly comprises the following steps: the thermal regeneration method is a method for desorbing substances adsorbed in the activated carbon by high-temperature heating or using high-temperature water vapor, and is the most widely applied method in the field of activated carbon regeneration at present; the chemical elution method is a method of extracting adsorbates adsorbed on activated carbon with an inorganic acid (sulfuric acid or hydrochloric acid), an alkali (sodium hydroxide) or an organic chemical (benzene, acetone, methanol, or the like). Further, there are a biological regeneration method, a wet oxidation regeneration method, a microwave radiation regeneration method, an electrochemical method, a supercritical fluid regeneration method, and the like. However, the methods have various problems, the regeneration efficiency of the thermal regeneration method is high, the equipment is complex and high in cost and easily causes carbon loss, the carbon loss of the medicament elution method is small, the regeneration is not thorough, the micropores are not easily eluted, and the adsorption property recovery rate is easily influenced by blockage; at present, no professional microwave regeneration heating device is available for microwave radiation, and a mature system suitable for industrial large-scale treatment is not available for a supercritical fluid and electrochemical regeneration method at present. The problems of reduction of carbon loss rate, reutilization of adsorbate, blockage of micropores, secondary pollution of tail gas and the like in the waste activated carbon regeneration process still need to be further solved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a waste activated carbon regeneration process which has the advantages of low carbon loss rate, thorough regeneration and good adsorption recovery rate.

The technical scheme adopted by the invention is as follows: a waste activated carbon regeneration process comprises the following steps:

A. pretreatment: cleaning the waste activated carbon with a distilled water solution, freezing to change liquid phase water in the waste activated carbon into solid water, and then placing the solid water in a vacuum freeze dryer for drying and dewatering;

B. soaking and eluting the regeneration solution: placing the waste activated carbon which is freeze-dried and dehydrated in the step A into a reaction kettle, introducing a regeneration liquid for soaking, wherein the soaking temperature is set to be 20-40 ℃, and the soaking elution time is 6-12 hours; meanwhile, a plurality of ultrasonic wave generating devices are arranged in the reaction kettle, the ultrasonic wave generators are started at intervals, the interval time is 40-60min each time, and the duration time of each time of sound wave action is 30-45 min; in the elution process, introducing nitrogen into the reaction kettle from top to bottom, vacuumizing the reaction kettle, and expanding the speed and the content of the regenerated liquid passing through the aperture by adopting a nitrogen cooling-vacuumizing method; the nitrogen cooling-vacuumizing is intermittently started and the ultrasonic vibration is alternately started. The interval time is 30-45min each time, and the continuous vacuum pumping time is 40-60 min;

C. recovering and replacing the regenerated liquid: replacing the regeneration liquid every 3-4h of soaking, inputting the waste regeneration liquid into a distillation device according to the boiling point of the solvent, and introducing the cooled and recovered regeneration liquid into the reaction kettle again, wherein the replacement times of the regeneration liquid are 2-4 times;

D. washing: washing the waste activated carbon soaked and eluted in the step C by using an ethanol solution with the concentration of 95%, and then washing the waste activated carbon to be in a neutral state by using distilled water;

E. drying: placing the activated carbon washed to be neutral in the step C in a rotary furnace for drying, wherein the drying temperature is 100-200 ℃; the heating speed is set to be 5-10 ℃/min, and the drying time is 6-10 h;

F. e, putting the dried sample in the reaction kettle again, introducing distilled water to soak for 1-2h, and simultaneously continuously oscillating the ultrasonic device to ensure that the distilled water fully enters the activated carbon channel; rapidly introducing nitrogen for freezing, completely freezing, and drying and dehydrating in a vacuum freeze dryer at-40 to-50 ℃ to obtain a finished product, wherein the freeze drying time is set to be 10-16 h;

G. tail gas treatment: and E, discharging the tail gas after the tail gas treatment reaches the standard.

Further, the ratio of the regeneration liquid to the waste activated carbon is 1.5:1, the temperature of the regeneration liquid is 25 ℃, and the soaking and elution time is 9 hours.

Furthermore, the ultrasonic wave generating device is two ultrasonic wave generators with different frequencies, and each ultrasonic wave generator is at least provided with two groups of vibrators.

Preferably, the ultrasonic generator is a double-frequency combination of 45KHz and 80 KHz.

Furthermore, the interval time of the ultrasonic generator starting is 60min, and the duration time of each sound wave action is 40 min.

Furthermore, the interval time of the nitrogen cooling-vacuumizing method is 40min, and the duration time of each vacuumizing is 60 min.

Further, the temperature of the freeze dryer in the step A and the temperature of the freeze dryer in the step F are both set to be-50 ℃, and the drying time is 12 hours.

Further, the organic solvent regeneration liquid is sodium hydroxide, potassium hydroxide, methanol, ethanol, isopropanol or acetone.

Compared with the prior art, the invention has the beneficial effects that: 1. on one hand, the regenerated liquid can be enhanced to enter the internal gap of the active carbon by utilizing the ultrasonic wave indirect oscillation. On the other hand, the regeneration liquid can be fully expanded and repeatedly invaded into a deeper inner gap of the active carbon by utilizing the pressure difference generated by the nitrogen cooling-indirect vacuum pumping method, so that the phenomenon of incomplete elution of the medicament can be greatly improved, and the regeneration effect of the waste active carbon is improved.

2. And after the elution is finished and the drying is finished, soaking the activated carbon by using distilled water again, and assisting ultrasonic oscillation to ensure that the distilled water fully enters the internal gaps of the activated carbon, freezing the activated carbon to ensure that liquid water is changed into solid ice with increased volume to amplify the internal gaps of the activated carbon, and removing water by using a vacuum freeze dryer under the condition of keeping the porous fluffy structure of the activated carbon to the maximum extent. The activated carbon regenerated by the process disclosed by the invention retains the advantage of low loss rate of the medicament elution carbon, greatly improves the phenomenon that the inside of the waste activated carbon is not thoroughly soaked and eluted, enlarges the internal gaps of the waste activated carbon, and improves the regeneration effect of the waste activated carbon.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the specific embodiments. It is to be understood that the described embodiments are merely exemplary of a portion of the invention and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

1. Weighing 10g of saturated waste activated carbon which is treated by water and adsorbs phenol, cleaning for 3 times by using distilled water, fully freezing for 3 hours in a freezer, taking out, quickly placing in a vacuum freeze dryer after precooling (cooling to below-50 ℃), and drying for 10 hours.

2. And taking out the dried waste activated carbon after the water is fully removed, putting the waste activated carbon into a reaction kettle filled with NaOH regeneration liquid, soaking at the temperature of 30 ℃ for 9 hours, replacing the regeneration liquid every 3 hours, introducing the replaced regeneration liquid into a distillation device, and cooling for recycling. And simultaneously, alternately starting an ultrasonic device and a nitrogen-vacuumizing device, setting the ultrasonic wave as a double-frequency combination, setting the frequency to be 45KHz &80KHz, setting the vibration duration to be 40min, and setting the nitrogen cooling-vacuumizing action time to be 60 min.

3. Washing the eluted activated carbon for 2 times by using a 95% ethanol solution, washing the activated carbon to be neutral by using distilled water, and determining whether the washing state is close to neutral by using a pH test paper, wherein the determined value is 6-7.

4. And (3) drying the activated carbon washed to be neutral in a rotary furnace, wherein the drying temperature is set to be 160 ℃, the heating speed is set to be 6 ℃/min, and the drying time is 12 h. The waste gas generated in the drying process is treated by an adsorption tower, a quenching and neutralizing tower, a drying tower, a bag-type dust remover and a spray tower and then is discharged after reaching the standard.

5. And putting the eluted and dried activated carbon into the reaction kettle again, introducing distilled water, fully soaking for 2 hours, and simultaneously continuing to vibrate by using an ultrasonic device to ensure that the distilled water fully enters the activated carbon pore channel after the phenol is eluted by the sodium hydroxide.

6. After soaking, rapidly introducing nitrogen into the reaction kettle for freezing, removing residual ice, and freeze-drying the completely frozen activated carbon in a vacuum freeze-drying machine at-50 ℃ for 14 hours.

7. The carbon loss rate of the activated carbon is determined to be less than 2 percent, and the regeneration effect reaches 96.02 percent. The specific surface area is recovered to 98.18%.

Example 2

1. Weighing 10g of saturated waste activated carbon which is treated by water and adsorbs phenol, cleaning for 3 times by using distilled water, fully freezing for 3 hours in a freezer, taking out, quickly placing in a vacuum freeze dryer after precooling (cooling to below-50 ℃), and drying for 10 hours.

2. And taking out the dried waste activated carbon after the water is fully removed, putting the waste activated carbon into a reaction kettle filled with NaOH regeneration liquid, soaking at the temperature of 30 ℃ for 12 hours, replacing the regeneration liquid every 4 hours, introducing the replaced regeneration liquid into a distillation device, and cooling for recycling. And simultaneously, alternately starting an ultrasonic device and a nitrogen-vacuumizing device, setting the ultrasonic wave as a double-frequency combination, setting the frequency to be 45KHz &80KHz, setting the vibration duration to be 30min, and setting the nitrogen cooling-vacuumizing action time to be 40 min.

3. Washing the eluted activated carbon for 2 times by using a 95% ethanol solution, washing the activated carbon to be neutral by using distilled water, and determining whether the washing state is close to neutral by using a pH test paper, wherein the determined value is 6-7.

4. And (3) drying the activated carbon washed to be neutral in a rotary furnace, wherein the drying temperature is set to be 160 ℃, the heating speed is set to be 6 ℃/min, and the drying time is 12 h. The waste gas generated in the drying process is treated by an adsorption tower, a quenching and neutralizing tower, a drying tower, a bag-type dust remover and a spray tower and then is discharged after reaching the standard.

5. And putting the eluted and dried activated carbon into the reaction kettle again, introducing distilled water, fully soaking for 2 hours, and simultaneously continuing to vibrate by using an ultrasonic device to ensure that the distilled water fully enters the activated carbon pore channel after the phenol is eluted by the sodium hydroxide.

6. After soaking, rapidly introducing nitrogen into the reaction kettle for freezing, removing residual ice, and freeze-drying the completely frozen activated carbon in a vacuum freeze-drying machine at-50 ℃ for 14 hours.

7. The carbon loss rate of the activated carbon is determined to be less than 2 percent, and the regeneration effect reaches 95.82 percent. The specific surface area is recovered by 96.38%.

Example 3

1. Weighing 10g of saturated waste activated carbon which is treated by water and adsorbs phenol, cleaning for 3 times by using distilled water, fully freezing for 3 hours in a freezer, taking out, quickly placing in a vacuum freeze dryer after precooling (cooling to below-50 ℃), and drying for 10 hours.

2. And taking out the dried waste activated carbon after the water is fully removed, putting the waste activated carbon into a reaction kettle filled with NaOH regeneration liquid, soaking at the temperature of 25 ℃ for 9 hours, replacing the regeneration liquid every 3 hours, introducing the replaced regeneration liquid into a distillation device, and cooling for recycling. And simultaneously, alternately starting an ultrasonic device and a nitrogen-vacuumizing device, setting the ultrasonic wave as a double-frequency combination, setting the frequency to be 45KHz &45KHz, setting the vibration duration to be 40min, and setting the nitrogen cooling-vacuumizing action time to be 60 min.

3. Washing the eluted activated carbon for 2 times by using a 95% ethanol solution, washing the activated carbon to be neutral by using distilled water, and determining whether the washing state is close to neutral by using a pH test paper, wherein the determined value is 6-7.

4. And (3) drying the activated carbon washed to be neutral in a rotary furnace, wherein the drying temperature is set to be 180 ℃, the heating rate is set to be 8 ℃/min, and the drying time is 12 h. The waste gas generated in the drying process is treated by an adsorption tower, a quenching and neutralizing tower, a drying tower, a bag-type dust remover and a spray tower and then is discharged after reaching the standard.

5. And putting the eluted and dried activated carbon into the reaction kettle again, introducing distilled water, fully soaking for 2 hours, and simultaneously continuing to vibrate by using an ultrasonic device to ensure that the distilled water fully enters the activated carbon pore channel after the phenol is eluted by the sodium hydroxide.

6. After soaking, rapidly introducing nitrogen into the reaction kettle for freezing, removing residual ice, and freeze-drying the completely frozen activated carbon in a vacuum freeze-drying machine at-50 ℃ for 14 hours.

7. The carbon loss rate of the activated carbon is determined to be less than 3 percent, and the regeneration effect reaches 97.12 percent. The specific surface area is recovered by 96.74%.

In the experiment of the influence of earlier stage comparison regeneration liquid temperature and ultrasonic frequency on regeneration efficiency, accurately weigh 1g and adsorb phenol saturated old and useless active carbon, 150 ml's distilled water is as the regeneration liquid, ultrasonic power 100W, adopt 45KHz &100KHz dual-frequency combination, the supersound action time sets for 30min, control regeneration liquid temperature 5 ℃, 15 ℃, 25 ℃, 35 ℃, 45 ℃, 55 ℃ respectively and do the active carbon regeneration efficiency experiment discovery, when other conditions do not change only control regeneration liquid temperature, it is best and tend to steady to obtain regeneration liquid temperature when 25 ℃, regeneration liquid temperature is higher than after 30 ℃ regeneration efficiency reduces along with the rising of regeneration liquid temperature on the contrary.

The temperature of the regeneration liquid is set to be 25 ℃, other conditions are unchanged, the ultrasonic power is adjusted to be 100W, the regeneration efficiency of the waste activated carbon adopting double-frequency vibration of the ultrasonic wave is obviously superior to that of a single-frequency condition, the frequency condition of double-frequency combination of the ultrasonic wave is changed, and the regeneration effects of the ultrasonic action of the double-frequency different combination on the activated carbon are sequentially from good to bad: 45KHz &45KHz, 45KHz &80KHz, 45KHz &100KHz, 80KHz &80KHz, 80KHz &100 KHz. However, when 45KHz and 45KHz are used, the regeneration noise is large, the regeneration liquid is least calm, the active carbon jumps violently, and the loss of the active carbon in the state is serious compared with other conditions.