Medium-temperature regeneration method and system for powdered activated carbon

Abstract

The invention relates to the technical field of activated carbon regeneration, and discloses a medium-temperature regeneration method and system for powdered activated carbon, and the method comprises the following steps: preparing waste activated carbon; preparing porcelain balls; drying the waste activated carbon; the waste activated carbon is fed into a regeneration tower through the chain bucket machine, and ceramic balls are conveyed to the chain bucket machine while the waste activated carbon falls onto the chain bucket machine, so that the ceramic balls enter the waste activated carbon; the waste activated carbon and the porcelain balls sequentially pass through the preheating section, the heating section and the cooling section of the regeneration tower. The ceramic balls and the waste activated carbon are conveyed to the regeneration tower together through the chain bucket machine, and in the process, the ceramic balls collide with and are mixed with powdery or granular activated carbon through vibration, so that hardening of the powdery activated carbon can be effectively avoided, complete conveying of the activated carbon and normal proceeding of subsequent procedures are effectively guaranteed, and the production efficiency is improved. In addition, the heating temperature is only 450 DEG C, the loss of the activated carbon is extremely low, the strength is not reduced, and the use effect is extremely good.

Description

Technical Field

[0001] The invention relates to the technical field of activated carbon regeneration, and in particular to a medium-temperature regeneration method and system for powdered activated carbon. Background Art

[0002] With the development of the activated carbon manufacturing industry and the expansion of its application fields, it is necessary to regenerate activated carbon, both from the perspective of economic benefits and environmental protection. This has become an important part of the activated carbon production and use technology. Whether the activated carbon is discarded after one use or recycled after regeneration is not only an important indicator of the technical level of the activated carbon industry, but also a choice that companies using activated carbon need to face. In recent years, the research, development and implementation of activated carbon regeneration in China have achieved certain results. Among them, the more mature techniques for activated carbon regeneration include thermal regeneration, extraction regeneration, oxidation regeneration, biological regeneration, etc. Of course, the thermal regeneration method is still the most commonly used method in industry at this stage.

[0003] Traditional high-temperature thermal regeneration methods include multi-layer furnace method, tubular furnace method, fluidized bed furnace method, stewing furnace method, disc furnace method, flow conveyor furnace method, etc. The medium generally used for high-temperature thermal regeneration is water vapor, flue gas, carbon dioxide and other gases. The advantages of high-temperature thermal regeneration method are: high regeneration efficiency, short regeneration time, and basically no selectivity for adsorbents.

[0004] The disadvantages of high-temperature thermal regeneration are: the carbon loss during the thermal regeneration process is large, generally 5-10%, the mechanical strength of the regenerated carbon decreases, and the chemical structure of the carbon surface changes; in addition, the equipment required for thermal regeneration is relatively complex, the operating cost is high, and it is not easy to miniaturize.

[0005] In the Chinese patent with publication number CN 104001488 B, an activated carbon regeneration device and regeneration method are disclosed. The method of the present invention feeds the waste activated carbon material into a drying converter through a feeding system, and then passes through a carbon collector, a dust collector, a hopper and a feeder, and the dried powder is sent to a boiling activation furnace, and the waste powdered carbon is activated in the high-temperature boiling activation furnace. The formed activated powder and furnace gas pass through the superheated steam heater in the pipeline to reheat the steam, and then the higher temperature activated powder and furnace gas enter the cyclone separator, and the collected activated carbon material is sent to the cooling feeder or sent to the packaging, or sent to the post-processing process. The technical solution of the present invention has low activated carbon regeneration cost, good regeneration quality, and the configured activated carbon drying and superheated steam boiling activation equipment system has a reasonable integrated design, simple operation, environmental friendliness, energy recycling, saving production costs, and realizing large-scale automated activated carbon reproduction.

[0006] At present, the regeneration of powdered activated carbon still uses high-temperature heating, and the activation temperature is 800-1000°C. However, under this temperature condition, superheated steam is used to dry and activate the activated carbon. Carbon combined with water vapor will produce carbon monoxide and hydrogen, which will still lead to carbon loss of 20%. The chemical structure of the carbon surface changes, resulting in a decrease in the mechanical strength of the regenerated carbon. In addition, high-temperature regeneration causes great pollution and energy consumption. At present, the treatment of desulfurized activated coke adopts a medium-temperature method, but this method still produces losses, and the existing technology is mainly aimed at activated carbon for water treatment. For the regeneration of powdered activated carbon, if the above method is adopted, the activated carbon is easily retained in the regeneration tower. The current regeneration method of powdered activated carbon requires granulation of the powdered carbon, regeneration after becoming granular activated carbon, and grinding after regeneration. The process is very cumbersome. Summary of the invention

[0007] The purpose of the present invention is to solve the problems existing in the prior art and to propose a medium-temperature regeneration method and system for powdered activated carbon.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A medium-temperature regeneration method for powdered activated carbon comprises the following steps:

[0010] Spent activated carbon preparation;

[0011] Porcelain ball preparation;

[0012] Drying the waste activated carbon;

[0013] The waste activated carbon is sent to the regeneration tower via the chain bucket conveyor, wherein, while the waste activated carbon falls onto the chain bucket conveyor, porcelain balls are conveyed onto the chain bucket conveyor so that the porcelain balls enter into the waste activated carbon;

[0014] The waste activated carbon and porcelain balls pass through the preheating section, heating section and cooling section of the regeneration tower in sequence, and the activated carbon is heated from room temperature to 450°C through the preheating section and heating section;

[0015] Get net carbon.

[0016] Preferably, the waste activated carbon includes powdered activated carbon and granular activated carbon.

[0017] Preferably, the diameter of the porcelain ball is 20 mm.

[0018] Preferably, the temperature of the preheating section is set to 100-150 degrees Celsius, and the temperature of the heating section is set to 150-550 degrees Celsius.

[0019] Preferably, the preheating section and the heating section are arranged together, and the heating method is steam heating. The steam flows upward from the heating section into the preheating section and then is discharged, wherein the temperature of the steam entering the heating section is 550 degrees Celsius.

[0020] Preferably, the method further includes exchanging heat from a heat exchanger in the cooling section to air, heating the air to obtain hot air, and utilizing the hot air to pre-dry the waste activated carbon.

[0021] Preferably, a medium-temperature regeneration system for powdered activated carbon is applied to a medium-temperature regeneration method for powdered activated carbon, comprising an activated carbon storage tank group, a porcelain ball storage tank group, a chain bucket conveyor and a regeneration tower, the chain bucket conveyor comprising a horizontal conveying part and a vertical conveying part, the horizontal conveying part and the vertical conveying part are connected, the output end of the vertical conveying part is connected to the input end of the regeneration tower, the regeneration tower comprises a preheating section, a heating section and a cooling section, the output ends of the activated carbon storage tank group and the heat storage ball storage tank are connected to the input end of the horizontal conveying part of the chain bucket conveyor, the porcelain ball storage tank is used to store porcelain balls, and the activated carbon storage tank group is used to store waste activated carbon.

[0022] Preferably, the cooling section includes a primary cooling section and a secondary cooling section, and also includes an electric heater and two fans, one of the fans sends gas into the secondary cooling section, and heat is exchanged in the secondary cooling section. The heat exchange generates hot air which is connected to the activated carbon storage tank group through a pipeline for pre-drying the activated carbon. The other fan is connected to the primary cooling section through a pipeline, so that the air passes through the primary cooling section, the electric heater, the heating section and the preheating section in sequence to complete the temperature cycle.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention transports the porcelain balls and waste activated carbon to the regeneration tower together in a chain bucket conveyor. During this process, the porcelain balls collide and mix with the powdered or granular activated carbon through vibration, which can effectively avoid the compaction of the powdered activated carbon and effectively ensure the integrity of the activated carbon transportation and the normal progress of subsequent processes. In addition, the heating temperature is designed to be only 450 degrees Celsius, the activated carbon loss is extremely low, the strength does not decrease, and the use effect is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic flow chart of a medium-temperature regeneration method for powdered activated carbon proposed by the present invention;

[0026] Figure 2 This is a schematic diagram of a medium-temperature regeneration system for powdered activated carbon proposed in the present invention.

[0027] In the figure, 1. activated carbon storage tank group; 2. porcelain ball storage tank group; 3. chain bucket conveyor; 4. regeneration tower; 5. horizontal conveying part; 6. vertical conveying part; 7. preheating section; 8. heating section; 9. cooling section; 10. fan; 11. primary cooling section; 12. secondary cooling section; 13. electric heater. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Reference Figure 1 , a medium-temperature regeneration method for powdered activated carbon, comprising the following steps:

[0030] S1, spent activated carbon preparation;

[0031] S2, porcelain ball preparation;

[0032] S3, drying the waste activated carbon;

[0033] S4, sending the waste activated carbon into the regeneration tower via the chain bucket conveyor, wherein, while the waste activated carbon falls onto the chain bucket conveyor, porcelain balls are conveyed onto the chain bucket conveyor, so that the porcelain balls enter into the waste activated carbon;

[0034] S5, the waste activated carbon and the porcelain ball pass through the preheating section, heating section and cooling section of the regeneration tower in turn, the activated carbon is heated from room temperature to 450°C through the preheating section and the heating section, and the porcelain ball and the waste activated carbon are moved into the regeneration tower together, which can solve a problem that if the powdered activated carbon is directly regenerated, it is easy to be retained in the regeneration tower. The porcelain ball collides and mixes with the powdered or granular activated carbon through vibration, which can effectively avoid the compaction of the powdered activated carbon and ensure the regeneration effect. Moreover, this regeneration method only needs to be heated to medium temperature, and there will be no problem of high temperature regeneration loss of activated carbon;

[0035] S6, to obtain net carbon.

[0036] In this embodiment, the waste activated carbon includes powdered activated carbon and granular activated carbon.

[0037] In this embodiment, the diameter of the porcelain ball is 20 mm.

[0038] In this embodiment, the temperature of the preheating section is set to 100-150 degrees Celsius, and the temperature of the heating section is set to 150-550 degrees Celsius.

[0039] In this embodiment, the preheating section and the heating section are arranged together, and the heating method is steam heating. The steam flows upward from the heating section into the preheating section and then is discharged, wherein the temperature of the steam entering the heating section is 550 degrees Celsius. At this time, the waste activated carbon enters the preheating section from the upper end of the regeneration tower. At this time, the steam in the heating section moves in the opposite direction to the waste activated carbon, so that when the waste activated carbon is in the preheating section, the temperature of the preheating section is 100~150 degrees Celsius, and when it reaches the heating section, the temperature of the heating section is 150~550 degrees Celsius, so that the temperature of the waste activated carbon can be around 450 degrees Celsius.

[0040] In this embodiment, the heat of the heat exchanger in the cooling section is also exchanged with air, the air is heated to obtain hot air, and the hot air is used to pre-dry the waste activated carbon. In the regeneration tower, the preheating section, the heating section and the cooling section all use steam heat exchange to heat the waste activated carbon, that is, the movement cavity of the waste activated carbon is connected to the channel for steam flow through a heat transfer medium to achieve heat exchange, and the heat in the cooling section can be used to dry the waste activated carbon after heat exchange, thereby realizing heat utilization and saving energy consumption.

[0041] like Figure 2 As shown, a medium-temperature regeneration system for powdered activated carbon is applied to a medium-temperature regeneration method for powdered activated carbon, including an activated carbon storage tank group, a porcelain ball storage tank group, a chain bucket machine and a regeneration tower, the chain bucket machine includes a horizontal conveying part and a vertical conveying part, the horizontal conveying part is connected to the vertical conveying part, the output end of the vertical conveying part is connected to the input end of the regeneration tower, the regeneration tower includes a preheating section, a heating section and a cooling section, the output ends of the activated carbon storage tank group and the heat storage ball storage tank are connected to the input end of the horizontal conveying part of the chain bucket machine, the porcelain ball storage tank is used to store porcelain balls, the activated carbon storage tank group is used to store waste activated carbon, the activated carbon storage tank group includes at least two activated carbon storage tanks, the gas after heat exchange in the cooling section can be connected to the bottom of the activated carbon storage tank, the top of the activated carbon storage tank has an exhaust hole, after the waste activated carbon enters the cooling section, it exchanges heat with the air, one can reduce the temperature of the waste activated carbon, and the other can transfer heat to the activated carbon storage tank to pre-dry the unregenerated waste activated carbon.

[0042] In this embodiment, the cooling section includes a primary cooling section and a secondary cooling section, and also includes an electric heater and two fans, one of which sends gas into the secondary cooling section for heat exchange in the secondary cooling section. The heat exchange generates hot air which is connected to the activated carbon storage tank group through a pipeline for pre-drying the activated carbon. The other fan is connected to the primary cooling section through a pipeline, so that the air passes through the primary cooling section, the electric heater, the heating section and the preheating section in sequence to complete the temperature cycle, and the secondary cooling section is used to pre-dry the unregenerated waste activated carbon. The primary cooling section can take in air through the fan, and then the air is passed into the electric heater for heating. The heated gas enters the heating section to heat the waste activated carbon, thereby reducing heat energy loss. In addition, the air can also cool the waste activated carbon.

[0043] In order to verify the effect of the present invention, an activation test was carried out on waste activated carbon using the present invention, as shown below:

[0044] Activation process: Take sewage with a COD of 6000 and use activated carbon for adsorption. In the activation test, the method of the present invention is used to regenerate the activated carbon. The number of regenerations, the loss of activated carbon each time, and the COD removal rate are shown in the following table:

[0045] Frequency of use Activated carbon loss COD removal rate 1 0 60% 2 0 59% 3 0 63% 4 0 62% 5 0 61% 6 0 68% 7 0 65% 8 0 65% 9 0 62% 10 0 59% 11 10% /

[0046] It can be concluded that when the waste activated carbon is activated by the present invention, the adsorption capacity will begin to decrease only after the 11th time, and the subsequent treatment of the activated carbon needs to be carried out using the existing technology. In the first 10 times, there is no loss and the strength does not decrease, and the COD removal rate remains basically stable. It can be seen that compared with the prior art, the present invention can effectively reduce the loss of activated carbon in the prior art. Due to the low heating temperature, the energy consumption is also reduced, and the regeneration cost of the activated carbon is greatly reduced.

[0047] 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.

Claims

1. A medium temperature regeneration method for powdered activated carbon, characterized in that: The following steps are involved: Spent activated carbon preparation; Porcelain ball preparation; Drying the waste activated carbon; The waste activated carbon is sent to the regeneration tower via the chain bucket conveyor, wherein, while the waste activated carbon falls onto the chain bucket conveyor, porcelain balls are conveyed onto the chain bucket conveyor so that the porcelain balls enter into the waste activated carbon; The waste activated carbon and porcelain balls pass through the preheating section, heating section and cooling section of the regeneration tower in sequence, and the activated carbon is heated from room temperature to 450°C through the preheating section and heating section; Get net carbon.

2. The medium-temperature regeneration method of powdered activated carbon according to claim 1, characterized in that: The waste activated carbon includes powdered activated carbon and granular activated carbon.

3. The medium-temperature regeneration method of powdered activated carbon according to claim 1, characterized in that: The diameter of the porcelain ball is 20 mm.

4. The medium-temperature regeneration method of powdered activated carbon according to claim 1, characterized in that: The temperature of the preheating section is set to 100-150 degrees Celsius, and the temperature of the heating section is set to 150-550 degrees Celsius.

5. The medium-temperature regeneration method of powdered activated carbon according to claim 1, characterized in that: The preheating section and the heating section are arranged together, and the heating method is steam heating. The steam flows upward from the heating section into the preheating section and then is discharged. The temperature of the steam entering the heating section is 550 degrees Celsius.

6. The medium-temperature regeneration method of powdered activated carbon according to claim 1, characterized in that: The method also includes exchanging heat from a heat exchanger in the cooling section to air, heating the air to obtain hot air, and using the hot air to pre-dry the waste activated carbon.

7. A medium temperature regeneration system for powdered activated carbon, applied to a medium temperature regeneration method for powdered activated carbon according to any one of claims 1 to 6, characterized in that: It includes an activated carbon storage tank group, a porcelain ball storage tank group, a chain bucket machine and a regeneration tower, the chain bucket machine includes a horizontal conveying part and a vertical conveying part, the horizontal conveying part is connected to the vertical conveying part, the output end of the vertical conveying part is connected to the input end of the regeneration tower, the regeneration tower includes a preheating section, a heating section and a cooling section, the output ends of the activated carbon storage tank group and the heat storage ball storage tank are connected to the input end of the horizontal conveying part of the chain bucket machine, the porcelain ball storage tank is used to store porcelain balls, and the activated carbon storage tank group is used to store waste activated carbon.

8. A medium temperature regeneration system for powdered activated carbon according to claim 7, characterized in that: The cooling section includes a primary cooling section and a secondary cooling section, and also includes an electric heater and two fans, one of which sends gas into the secondary cooling section for heat exchange in the secondary cooling section. The hot air generated by the heat exchange is connected to the activated carbon storage tank group through a pipeline for pre-drying the activated carbon. The other fan is connected to the primary cooling section through a pipeline, so that the air passes through the primary cooling section, the electric heater, the heating section and the preheating section in sequence to complete the temperature cycle.

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