An activated carbon preparation device and method

Abstract

The application discloses a kind of activated carbon preparation device and method, it is related to activated carbon preparation technical field.The activated carbon preparation device includes that raw material mixing tank is sequentially connected from top to bottom, fluidized bed carbonization furnace, activating agent mixing drying furnace and activation furnace, filter plate is equipped in activating agent mixing drying furnace, first stirring mechanism is located above filter plate and vibration mechanism is located below filter plate, and the top side of activating agent mixing drying furnace is equipped with activating agent adding mechanism with its furnace inner space being communicated, the power output end of first stirring mechanism is linked with activating agent adding mechanism in one way, to expose and close the discharge opening of activating agent adding mechanism periodically, complete the periodic intermittent addition of activating agent, and the power end of first stirring mechanism is linked with vibration mechanism in another way, to periodically drive vibration mechanism to vibrate filter plate.The activated carbon preparation efficiency of the application is high, and carbonization activity consistency is good, also improves the high value-added of biomass, energy saving and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of activated carbon preparation technology, specifically to an activated carbon preparation apparatus and method with high preparation efficiency and good carbonization activity consistency. Background Technology

[0002] Activated carbon is an adsorbent material with abundant pore structure and a large specific surface area, and is widely used in water treatment, air purification, food industry, and other fields. Currently, the main methods for preparing activated carbon include physical activation, chemical activation, and combined physical-chemical activation. Among these, the two-step pyrolysis method is a relatively effective preparation method, which first carbonizes the raw material and then activates it, effectively improving the performance of the activated carbon.

[0003] However, existing activated carbon preparation processes still have many problems: First, in the raw material mixing stage, traditional equipment does not mix sludge and biomass sufficiently, which easily leads to uneven mixing of the two raw materials, thus affecting the stability of subsequent carbonization reactions and the quality of the carbonized material; Second, in the activator addition and mixing stage, alkaline activators are often added in large quantities at once, making it difficult to uniformly integrate with the carbonized material, resulting in insufficient activation reaction and reducing the pore structure development effect of activated carbon; Third, in the material screening stage after mixing and drying, commonly used screening devices are often fixed and have poor separation effect on carbon powder of different particle sizes, resulting in uneven particle size distribution of carbon powder entering the activation furnace, affecting the performance consistency of the final activated carbon product; Fourth, the continuity of each stage in existing equipment is poor, the overall preparation efficiency is low, and it is difficult to meet the needs of large-scale production. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, this invention provides an activated carbon preparation apparatus and method with high preparation efficiency and good carbonization activity consistency.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned technical effects is as follows:

[0006] An activated carbon preparation apparatus includes a raw material mixing tank, a fluidized bed carbonization furnace, an activator mixing and drying furnace, and an activation furnace connected sequentially from top to bottom. The activator mixing and drying furnace is equipped with a movably mounted filter plate, a first stirring mechanism located above the filter plate, and a vibration mechanism located below the filter plate. An activator adding mechanism, communicating with its internal space, is located on the top periphery of the activator mixing and drying furnace. One power output of the first stirring mechanism is linked to the activator adding mechanism to periodically drive the feed port of the activator adding mechanism to open and close, completing the periodic intermittent addition of the activator. The other power output of the first stirring mechanism is linked to the vibration mechanism to periodically drive the vibration mechanism to vibrate the filter plate.

[0007] Preferably, in the activated carbon preparation apparatus described above, the first stirring mechanism includes a first stirring shaft that horizontally penetrates the activator mixing and drying furnace and a first motor that is drively connected to the first stirring shaft. The two ends of the first stirring shaft extend outside the activator mixing and drying furnace, forming its linkage part, and are respectively linked with the activator adding mechanism and the vibration mechanism.

[0008] Preferably, in the activated carbon preparation device described above, the activator addition mechanism includes an activator addition hopper, a discharge port opening and closing control bolt, a linkage cam, and a first spring. The activator addition hopper has a discharge nozzle that is connected to and fixed to the top periphery of the activator mixing and drying furnace. The discharge port opening and closing control bolt has a "door" shaped structure, with an outer bolt plate bent vertically downward at the outer end and an inner bolt plate bent vertically downward at the inner end. The outer bolt plate has a side opening for the discharge nozzle to pass through. The top of the activator mixing and drying furnace has a first sliding hole for the inner bolt plate to be movably assembled therein. The lower end of the inner bolt plate can move up and down to contact and disengage from the nozzle opening, so that the nozzle opening is exposed and closed. The first spring is connected between the middle part of the discharge port opening and closing control bolt and the top of the activator mixing and drying furnace. The linkage cam is fixedly connected to the linkage part of the first stirring shaft, and its rim slides against the lower end of the outer bolt plate.

[0009] Preferably, in the activated carbon preparation device described above, the vibration mechanism includes a vertically arranged reciprocating slide bar, a horizontal connecting rod fixed at the lower end of the reciprocating slide bar, a first ball fixed at the inner end of the horizontal connecting rod, and a second ball disposed on the lower surface of the filter plate. The linkage part of the first stirring shaft is provided with a bidirectional threaded groove. The upper end of the reciprocating slide bar is drivenly connected to the bidirectional threaded groove. The side wall of the activator mixing and drying furnace is provided with a second sliding hole for the horizontal connecting rod to be movably assembled therein. The filter plate vibrates and sieves under the dynamic reciprocating compression of the first ball against the second ball.

[0010] Preferably, in the activated carbon preparation apparatus described above, the inner wall of the activator mixing and drying furnace is provided with a plurality of annularly arranged baffle steps, the bottom of the filter plate rests on the baffle steps, and a second spring connects the baffle steps and the bottom of the filter plate.

[0011] Preferably, in the activated carbon preparation device described above, a motor support arm is provided on the activator addition hopper corresponding to the first motor and is fixedly connected to the hopper body. The corresponding shaft end of the first stirring shaft is rotatably connected to the lower end of the motor support arm, and the first motor is fixedly connected to the lower end of the motor support arm.

[0012] Preferably, in the activated carbon preparation apparatus described above, a first rotary valve is provided in the connection channel between the raw material mixing tank and the fluidized bed carbonization furnace, a second rotary valve is provided in the fluidized bed carbonization furnace, and a third rotary valve is provided in the activation furnace. A first nitrogen addition pipe is connected to the fluidized bed carbonization furnace above the second rotary valve, and a second nitrogen addition pipe is connected to the activation furnace above the third rotary valve.

[0013] A method for preparing activated carbon based on the above-mentioned device, characterized by comprising the following steps: Step 1: Raw material pretreatment. The sludge is dewatered and dried, crushed and sieved to obtain sludge powder with a particle size of 80-120 mesh. The biomass is sieved in the same way to obtain biomass powder with a particle size of 80-120 mesh. Step 2: Raw material mixing. According to the weight ratio, the sludge powder and biomass powder obtained in Step 1 are mixed in a ratio of sludge powder:biomass powder = 1:1, and then put into the raw material mixing tank for thorough stirring and mixing. Step 3: Carbonization treatment. The raw materials obtained by thorough mixing in step 2 are fed into the fluidized bed carbonization furnace, where they undergo a carbonization reaction to form carbonized material. Step 4: Activator mixing. The carbonized material obtained in Step 3 is fed into the activator mixing and drying furnace. Liquid activator is then periodically added into the furnace through the activator adding mechanism. Simultaneously, the carbonized material and activator are stirred and mixed by the first stirring mechanism, and the filter plate is periodically vibrated by the vibration mechanism to screen out carbon powder with uniform particle size. The solid-liquid ratio is 1:3 for carbonized material to activator. Step 5: Carbon powder activation treatment. The carbon powder screened in step 4 falls into the activation furnace. Nitrogen gas is introduced into the activation furnace and heated to 750℃~850℃. High-temperature activation is carried out for 50~70 minutes to obtain activated carbon with uniform particle size.

[0014] Preferably, in the above-described method for preparing activated carbon, the activating agent is a KOH solution.

[0015] Preferably, in the above-described activated carbon preparation method, in step 3, nitrogen gas is introduced into the fluidized bed carbonization furnace during the carbonization reaction of the raw materials.

[0016] The beneficial effects of this invention are as follows: This invention allows for thorough mixing of sludge and biomass in a raw material mixing tank, followed by carbonization in a fluidized bed carbonization furnace to obtain carbonized material. In an activator mixing and drying furnace, activator is added intermittently to ensure uniform mixing of the carbonized material and activator, followed by sieving to separate carbon powder with uniform particle size. Finally, high-temperature activation is performed in an activation furnace to obtain activated carbon with good carbonization activity consistency. The activator addition mechanism and vibration mechanism of this invention, linked with the first mixing mechanism, not only ensure the continuity of each step but also simplify the power structure. Intermittent addition of activator avoids uneven mixing caused by large-scale single addition, ensuring thorough mixing of the activator and carbonized material. Periodic vibration of the filter plate enables efficient and precise separation of carbon powder with different particle sizes. This invention achieves comprehensive resource utilization of sludge and corn stalks, effectively avoiding secondary pollution that may be caused by direct treatment or disposal. It realizes high-value utilization of biomass such as corn stalks, with significant energy-saving and environmental benefits. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a structural diagram of the present invention from a first perspective; Figure 3 This is a structural diagram of the present invention from a second perspective; Figure 4 This is a cross-sectional view of the present invention; Figure 5 for Figure 1 An enlarged view of part "A" in the image; Figure 6 for Figure 2 An enlarged view of section "B" in the middle; Figure 7 for Figure 4 An enlarged view of section "C" in the middle; Figure 8 This is a diagram showing the closed state of the feed nozzle as described in this invention; Figure 9 for Figure 2 Enlarged view of section "D" in the middle; Figure 10 This is a graph showing the effect of material ratio on iodine adsorption value in the experiments of this invention; Figure 11 This is a graph showing the effect of the solid-liquid ratio on the iodine adsorption value in the experiments of this invention. Figure 12 This is a graph showing the effect of activation temperature on iodine adsorption value in the experiments of this invention; Figure 13 This is a graph showing the effect of activation time on iodine adsorption value in the experiments of this invention. Detailed Implementation

[0018] To provide a further understanding of the present invention, the invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0019] In the description of this invention, it should be noted that the terms "vertical," "upper," "lower," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Example

[0021] Please see Figures 1 to 4 As shown in the figure, an embodiment of the present invention provides an activated carbon preparation apparatus, which includes, from top to bottom, a raw material mixing tank 1, a fluidized bed carbonization furnace 2, an activator mixing and drying furnace 3, and an activation furnace 4 connected in sequence. Specifically, as shown... Figure 4 As shown, a first rotary valve 9 is provided at the connection channel between the raw material mixing tank 1 and the fluidized bed 2. A second rotary valve 91 is provided in the fluidized bed carbonization furnace 2, and a third rotary valve 92 is provided in the activation furnace 4. A first nitrogen injection pipe 21 is connected to the fluidized bed carbonization furnace 2 above the second rotary valve 91, and a second nitrogen injection pipe 41 is connected to the activation furnace 4 above the third rotary valve 92. The first rotary valve 9, the second rotary valve 91, and the third rotary valve 92 are all rotary plate valves. Nitrogen can be introduced into the fluidized bed carbonization furnace 2 and the activation furnace 4 through the first nitrogen injection pipe 21 and the second nitrogen injection pipe 41, respectively, to maintain a nitrogen atmosphere inside the furnace.

[0022] As an improvement of the present invention, such as Figure 4As shown, the activator mixing and drying furnace 3 is equipped with a movable filter plate 31, a first stirring mechanism 5 located above the filter plate 31, and a vibration mechanism 7 located below the filter plate 31. The filter plate 31 is used to receive the carbonized material released from the fluidized bed carbonization furnace 2. The first stirring mechanism 5 further stirs the carbonized material entering the fluidized bed carbonization furnace 2. The vibration mechanism 7 is used to periodically vibrate the filter plate 31 so that the filter plate 31 dynamically screens the carbonized material falling on it. Figure 4 As shown, the top periphery of the activator mixing and drying furnace 3 is provided with an activator adding mechanism 6 that is connected to the furnace interior space. One power output end of the first stirring mechanism 5 is linked to the activator adding mechanism 6 to periodically drive the discharge port of the activator adding mechanism 6 to open and close, thereby completing the periodic intermittent addition of activator. The other power output end of the first stirring mechanism 5 is linked to the vibration mechanism 7 to periodically drive the vibration mechanism 7 to vibrate the filter plate 31.

[0023] The activator addition mechanism 6 and the vibration mechanism 7, linked with the first stirring mechanism 5, not only ensure the continuity of each step but also simplify the power structure. Periodic intermittent addition of the activator avoids uneven mixing caused by large-scale single addition, ensuring thorough mixing of the activator and the carbonized material. Periodic vibration of the filter plate 31 enables efficient and precise separation of carbon powder of different particle sizes. This invention's device achieves comprehensive resource utilization of sludge and corn stalks, effectively avoiding secondary pollution that could be caused by direct treatment or disposal of these wastes. It realizes high-value utilization of biomass such as corn stalks, demonstrating significant energy-saving and environmental benefits.

[0024] Furthermore, in a preferred embodiment of the present invention, such as Figure 4 As shown, the raw material mixing tank 1 is equipped with a second stirring device 8. When the sludge powder and biomass powder enter the raw material mixing tank 1, the second stirring device 8 is used to fully stir and mix the sludge powder and biomass powder to ensure that the two raw materials are mixed evenly, so as to provide a stable mixed raw material for the subsequent carbonization process.

[0025] Furthermore, in a preferred embodiment of the present invention, such as Figure 4As shown, the first stirring mechanism 5 includes a first stirring shaft 51 horizontally penetrating the activator mixing and drying furnace 3 and a first motor 52 drivenly connected to the first stirring shaft 51. The two ends of the first stirring shaft 51 extend outside the activator mixing and drying furnace 3, forming its linkage part, which is linked with the activator adding mechanism 6 and the vibration mechanism 7, respectively. That is, when the first stirring mechanism 5 stirs and mixes the carbonized material and activator in the activator mixing and drying furnace 3, the linkage part at the outer end of the first stirring shaft 51 also synchronously drives the activator adding mechanism 6 and the vibration mechanism 7 to perform corresponding activator adding and sieving actions. This causes the activator adding mechanism 6 to periodically add activator to the activator mixing and drying furnace 3, and the vibration mechanism 7 to periodically vibrate the filter plate 31, enabling it to screen and separate the mixed and dried material to obtain carbon powder with uniform particle size.

[0026] Furthermore, in a preferred embodiment of the present invention, such as Figure 4 , Figure 5 and Figure 7 As shown, the activator adding mechanism 6 includes an activator adding hopper 61, a discharge port opening and closing control bolt 62, a linkage cam 63, and a first spring 64. Among them, as... Figure 5 and Figure 7 As shown, the activator addition hopper 61 has a discharge nozzle 611 that is connected to and fixed to the top periphery of the activator mixing and drying furnace 3, and the discharge nozzle 611 extends into the interior of the activator mixing and drying furnace 3. It should be noted that only the core structure of the discharge nozzle 611 and part of the hopper body structure are shown in the figure of the activator addition hopper 61, and the hopper body stores the activator to be added into the activator mixing and drying furnace 3.

[0027] like Figure 7 As shown, the discharge port opening and closing control bolt 62 has a "door" shaped structure. Its outer end is vertically bent downwards to form an outer bolt plate 621, and its inner end is vertically bent downwards to form an inner bolt plate 622. The outer bolt plate 621 has a side opening 6211 for the discharge nozzle 611 to pass through. The side opening 6211 has sufficient length to prevent interference between the outer bolt plate 621 and the discharge nozzle 611 during vertical movement. Figure 7 As shown, the top of the activator mixing and drying furnace 3 is provided with a first sliding hole 32 for the inner bolt plate 622 to be movably assembled therein. The lower end of the inner bolt plate 622 can move up and down to contact and disengage from the nozzle 611, so that the nozzle 611 is exposed and closed, thereby allowing the activator to be added intermittently to the activator mixing and drying furnace 3.

[0028] like Figure 5 and Figure 7As shown, the first spring 64 is connected between the middle of the plug body of the discharge port opening and closing control plug 62 and the top of the activator mixing and drying furnace 3. The linkage cam 63 is fixedly connected to the linkage part of the first stirring shaft 51, and its rim slides against the lower end of the outer plug plate 621. As the first stirring shaft 51 rotates, the linkage cam 63 on it also rotates synchronously and contacts the lower end of the outer plug plate 621 during the rotation. With the rotation of the linkage cam 63, the entire discharge port opening and closing control plug 62 overcomes the elastic force of the first spring 64 and moves back and forth in the vertical direction, thereby causing the lower end of the inner plug plate 622 to contact and disengage from the opening of the discharge nozzle 611, repeatedly exposing and closing the opening of the discharge nozzle 611. Specifically, as Figure 7 As shown, the nozzle 611 is in the closed state. Figure 8 The image shows the exposed state of the feed nozzle 611. Through the aforementioned linkage control, the activator in the activator addition hopper 61 is intermittently added to the activator mixing and drying furnace 3.

[0029] Furthermore, in a preferred embodiment of the present invention, such as Figure 5 , Figure 6 As shown, the vibration mechanism 7 includes a vertically arranged reciprocating slide rod 71, a horizontal connecting rod 72 fixed to the lower end of the reciprocating slide rod 71, a first ball 721 fixed to the inner end of the horizontal connecting rod 72, and a second ball 311 disposed on the lower surface of the filter plate 31. Wherein, as... Figure 5 As shown, the linkage part of the first stirring shaft 51 is provided with a bidirectional threaded slide groove 511. The upper end of the reciprocating slide rod 71 is drivenly connected to the bidirectional threaded slide groove 511. As the first stirring shaft 51 rotates, it can drive the reciprocating slide rod 71 to reciprocate on the shaft section where the bidirectional threaded slide groove 511 is located. The side wall of the activator mixing and drying furnace 3 is provided with a second sliding hole for the horizontal connecting rod 72 to be movably assembled therein. The inner end of the horizontal connecting rod 72 is located in the activator mixing and drying furnace 3. As the first stirring shaft 51 rotates, it drives the reciprocating slide rod 71 to reciprocate, which in turn drives the horizontal connecting rod 72 and the first ball 721 to reciprocate, so that the first ball 721 reciprocates to press the second ball 311 on the lower surface of the filter plate 31, thereby driving the filter plate 31 to vibrate. The vibrating filter plate 31 sieves the material mixed and dried in the activator mixing and drying furnace 3 to obtain carbon powder with a uniform particle size.

[0030] Furthermore, such as Figure 6As shown, the inner wall of the activator mixing and drying furnace 3 is provided with several annularly arranged baffle steps 312. The bottom of the filter plate 31 rests on the baffle steps 312, and a second spring 313 connects the baffle steps 312 and the bottom of the filter plate 31. When the first ball 721 presses the second ball 311 inward, the filter plate 31 is raised by the pressure, and the second spring 313 is stretched. When the first ball 721 moves outward away from the second ball 311, the filter plate 31 is reset under its own weight and the reset action of the stretched second spring 313. It should be noted that in some embodiments of the present invention, the second spring 313 may be omitted, that is, the filter plate 31 can be reset by its own repositioning.

[0031] Furthermore, in a preferred embodiment of the present invention, such as Figure 5 and Figure 7 As shown, on an activator adding hopper 61 corresponding to the first motor 52, there is a motor support arm 53 fixedly connected to the hopper body. The corresponding shaft end of the first stirring shaft 51 is rotatably connected to the lower end of the motor support arm 53. The first motor 52 is fixedly connected to the lower end of the motor support arm 53, and the motor support arm 53 provides fixed support for the first motor 52.

[0032] In some embodiments of the present invention, such as Figure 2 , Figure 4 , Figure 9As shown, the second stirring device 8 includes a second stirring shaft 81 horizontally arranged in the raw material mixing tank 1 and a second motor 82 fixed to the side wall of the raw material mixing tank 1. One end of the second stirring shaft 81 is connected to the second motor 82 for transmission. The inner wall of the fluidized bed carbonization furnace 2 is provided with a heating bushing 22, which provides the temperature required for the carbonization reaction to the fluidized bed carbonization furnace 2. When the raw material mixing tank 1 is stirring the sludge powder and biomass powder, the first rotary valve 9 is in the closed state, so that the connection channel between the raw material mixing tank 1 and the fluidized bed carbonization furnace 2 is closed. After the raw material mixing tank 1 has fully stirred and mixed the sludge powder and biomass powder, the first rotary valve 9 is opened, allowing the mixture to fall into the fluidized bed carbonization furnace 2 below, where it is received by the second rotary valve 91, which is in the closed state. Then, the mixture is heated by the fluidized bed carbonization furnace 2, causing the mixture to undergo a carbonization reaction. During the carbonization reaction, nitrogen gas is introduced into the fluidized bed carbonization furnace 2 through the first nitrogen addition pipe 21 to provide the carbonization reaction atmosphere. After carbonization is completed, the second rotary valve 91 is turned open, allowing the carbonized material to fall into the activator mixing and drying furnace 3 below, where it is received by the filter plate 31. While the first stirring mechanism 5 stirs the carbonized material, the activator addition mechanism 6 also periodically and intermittently adds activator to the activator mixing and drying furnace 3, and the activator is fully mixed with the carbonized material under the stirring of the first stirring mechanism 5. During this process, the vibration mechanism 7 periodically vibrates the filter plate 31 to screen out carbon powder with uniform particle size. The screened carbon powder finally enters the activation furnace 4 and is received by the third rotary valve 92, which is in the closed state. Under the high temperature of 750℃~850℃ provided by the activation furnace 4, the carbon powder is activated to produce activated carbon with good carbonization activity uniformity. During the carbon powder activation, nitrogen gas is introduced into the activation furnace 4 through the second nitrogen addition pipe 41 to provide the reaction atmosphere for carbon powder activation. Example

[0033] The present invention also provides a method for preparing activated carbon based on the above-described apparatus, the method comprising the following steps: Step 1: Raw material pretreatment. The sludge is dewatered and dried, crushed and sieved to obtain sludge powder with a particle size of 80-120 mesh. The biomass is sieved in the same way to obtain biomass powder with a particle size of 80-120 mesh. Step 2: Mixing raw materials. According to the weight ratio, the sludge powder and biomass powder obtained in Step 1 are mixed in a ratio of sludge powder:biomass powder = 1:1. Then, they are put into the raw material mixing tank 1 and thoroughly stirred and mixed. Step 3: Carbonization treatment. The raw materials obtained by thorough mixing in step 2 are fed into fluidized bed carbonization furnace 2, where they undergo a carbonization reaction to form carbonized material. Step 4: Activator mixing. The carbonized material obtained in step 3 is fed into the activator mixing and drying furnace 3. Then, liquid activator is periodically added into the activator mixing and drying furnace 3 through the activator adding mechanism 6. At the same time, the carbonized material and activator are stirred and mixed by the first stirring mechanism 5, and the filter plate 31 is periodically vibrated by the vibration mechanism 7 to screen out carbon powder with uniform particle size. The solid-liquid ratio is 1:3 for carbonized material to activator. Step 5: Carbon powder activation treatment. The carbon powder screened in step 4 falls into activation furnace 4. Nitrogen gas is introduced into activation furnace 4 and heated to 750℃~850℃. High-temperature activation is carried out for 50~70 minutes to obtain activated carbon with uniform particle size.

[0034] Furthermore, in a preferred embodiment of the present invention, the activator is a KOH solution. During the carbonization reaction of the raw materials in step 3, nitrogen gas is also introduced into the fluidized bed carbonization furnace 2.

[0035] In a preferred embodiment of the present invention, in step 5, the heating temperature is raised to 800°C and the high-temperature activation time is 60 minutes.

[0036] The preparation method of the present invention will be verified by some experimental examples below.

[0037] This experimental study used sewage sludge and biomass corn straw as research objects. The urban sewage sludge was selected from a sewage treatment plant in Chongqing. The sludge had been dewatered at the plant and then dried in a laboratory drying oven at 105℃ for 48 hours. Afterward, it was pulverized and screened to a particle size of 100 mesh before being bagged. The biomass used was corn straw from a rural area, which was also dried in a laboratory drying oven at 105℃ for 48 hours, pulverized, and screened to a particle size of 100 mesh as the research material. In this text, SS (Sewage Sludge) refers to the sewage sludge powder sample, and CS (Corn Straw) refers to the corn straw powder sample.

[0038] The industrial analysis results and elemental analysis results of sewage sludge and corn stalks are shown in Tables 1 and 2: Table 1 Industrial analysis of experimental samples

[0039] Table 2 Elemental analysis of experimental samples

[0040] Performance test and analysis results of this experiment: The performance of activated carbon was evaluated by determining the iodine value of activated carbon in sludge. The iodine adsorption value of activated carbon in sludge was determined according to the determination standard of GB / T 12496.8-2015 "Test Methods for Iodine Adsorption Value of Wood-based Activated Carbon".

[0041] This experimental example provides a method for preparing activated carbon using the apparatus of the present invention by mixing sludge and corn stalks. The material ratio (mass ratio of sludge to corn stalks), solid-liquid ratio, activation temperature, and activation time were selected as research factors. Iodine adsorption value was used as the evaluation target for activated carbon performance. The influence of each factor on the iodine adsorption value of activated carbon was systematically investigated. Activated carbon prepared by mixing sludge and corn stalks with KOH as the activating agent was denoted as KSC; activated carbon prepared by mixing sludge and corn stalks with NaOH as the activating agent was denoted as NSC; activated carbon prepared by mixing sludge and corn stalks with KOH-NaOH as the activating agent was denoted as KNSC. The specific experimental procedure is as follows:

[0042] I. Investigating the effect of material ratio on iodine adsorption value The effect of material ratio (1:1 to 4:1) on the iodine adsorption value of activated carbon was investigated under the conditions of activation temperature of 800℃, activation time of 60 min, and solid-liquid ratio of 1:3. The results are as follows: Figure 10 As shown.

[0043] Depend on Figure 10 It can be seen that the iodine adsorption value increases significantly with the increase of corn straw ratio, but the increase is non-linear. When the sludge ratio is high (4:1), the inorganic ash content in the sludge is high during the activation process, the carbon source is relatively limited, the micropore formation is inhibited, the pore volume and specific surface area are small, resulting in a low iodine adsorption value. As the corn straw ratio increases, when the material ratio is 3:1 and 2:1, the abundant cellulose and hemicellulose in the straw provide more carbonizable carbon sources, the reaction between the activator and the carbonization precursor is more complete, the microporous structure is significantly developed, and the iodine adsorption value rises rapidly. When the material ratio reaches 1:1, the carbon source and activator ratios are close, the micropore volume, pore size distribution and connectivity reach their peak values, and the iodine adsorption value reaches its highest value.

[0044] II. Study on the effect of solid-liquid ratio on iodine adsorption value The effect of solid-liquid ratio (1:1 to 1:4) on the iodine adsorption value of activated carbon was investigated under the conditions of a material ratio of 1:1, activation temperature of 800℃, and activation time of 60 min. The results are as follows: Figure 11 As shown.

[0045] Depend on Figure 11It can be seen that the iodine adsorption value exhibits a non-linear trend of first increasing and then decreasing with the change of solid-liquid ratio. When the solid-liquid ratio is low (1:1), the activator dosage is relatively insufficient, the contact between the carbon source and the activator is inadequate, and the micropores are not fully formed, resulting in a low iodine adsorption value. As the solid-liquid ratio increases to 1:3, the activator dosage is relatively sufficient, the activator can fully react with the carbonization precursor, the micropore structure is well developed, and the pore volume and specific surface area increase significantly, causing the iodine adsorption value to reach its peak. However, when the solid-liquid ratio further increases to 1:4, the activator is relatively excessive. Excessive alkaline activator may lead to excessive local corrosion of micropores or the formation of macropores, reducing the proportion of micropores, causing a decrease in specific surface area and micropore volume, thus slightly decreasing the iodine adsorption value.

[0046] III. Study on the effect of activation temperature on iodine adsorption value The effect of activation temperature (600, 700, 800, and 900℃) on the iodine adsorption value of activated carbon was investigated under the conditions of a material ratio of 1:1, a solid-liquid ratio of 1:3, and an activation time of 60 min. The results are as follows: Figure 12 As shown.

[0047] Depend on Figure 12 It can be seen that as the activation temperature increases from 600℃ to 800℃, the iodine adsorption value of activated carbon increases significantly, while when it further increases to 900℃, the iodine adsorption value decreases slightly. This nonlinear change is mainly attributed to the balance between the development of the microporous structure and the thermal stability of the carbon skeleton. At low temperatures (600℃), the reaction between the activator and the carbonization precursor is insufficient, and the micropores are not fully formed, resulting in small pore volume and specific surface area, leading to low iodine adsorption capacity. As the temperature rises to 700℃, the chemical corrosion effect of the activator is enhanced, and cellulose, hemicellulose, and organic matter are effectively decomposed, forming more micropores, and the iodine adsorption value increases accordingly. At 800℃, the micropore development of the carbon skeleton reaches its optimal state, with abundant pore structure and good connectivity, and the adsorption capacity reaches its peak. When the temperature further rises to 900℃, the high temperature may cause some micropores to collapse or the carbon skeleton to be excessively ablated, resulting in a slight decrease in specific surface area and pore volume, thus causing a slight decrease in the iodine adsorption value.

[0048] IV. Study on the effect of activation time on iodine adsorption value The effect of activation time (30, 60, 90, and 120 min) on the iodine adsorption value of activated carbon was investigated under the conditions of a material ratio of 1:1, a solid-liquid ratio of 1:3, and an activation temperature of 800℃. The results are as follows: Figure 13 As shown.

[0049] Depend on Figure 13It can be seen that the iodine adsorption value changes non-linearly with activation time, initially increasing rapidly and then stabilizing. When the activation time is short (30 min), the carbon source and activator have insufficient contact, the microporous structure has not yet fully formed, the specific surface area and pore volume are low, and the iodine adsorption value is at its lowest. As the activation time is extended to 60–90 min, the microporous structure is fully developed, the pore volume, specific surface area and connectivity reach their peak values, and the iodine adsorption value rapidly rises to its highest level. When the activation time is further extended to 120 min, over-activation may cause some micropores to collapse or macropores to form, resulting in a slight decrease in specific surface area and a slight decrease or stabilization of the iodine adsorption value.

[0050] Therefore, the optimal preparation process of the present invention is as follows: material ratio 1:1, solid-liquid ratio 1:3, activation temperature 800℃, and activation time 60 min. Under these conditions, activated carbon prepared using three different activating agents—KOH solution, NaOH solution, and KOH-NaOH solution—showed the highest iodine value among those prepared using KOH solution as the activating agent, at 786.92 mg / g, 746.85 mg / g, and 679.27 mg / g, respectively. The above experimental examples demonstrate that the activated carbon prepared by the present invention possesses certain adsorption properties and can be applied in the field of wastewater treatment. Furthermore, the raw materials for the activated carbon of the present invention are derived from dewatered sludge and corn stalks from wastewater treatment plants, enabling resource utilization of sludge and waste foam plastics and reducing secondary pollution.

[0051] This invention incorporates corn stalks as a carbon-enhancing material into the preparation of sludge-based activated carbon, compensating for the insufficient carbon content in sludge. By fully integrating the activator with the carbonized material, the activation reaction is ensured to proceed fully, promoting the development of the activated carbon's pore structure, improving its performance, and ensuring uniform particle size distribution of the carbon powder entering the activation furnace, thus guaranteeing the consistency of the final activated carbon product's performance. The operation is simple, and it utilizes waste resources for secondary purposes. It effectively avoids the secondary pollution that direct treatment or disposal of corn stalks might cause to the environment, achieving high-value utilization of corn stalks, fully embodying the green concepts of clean production and circular economy, and demonstrating significant energy-saving and environmental benefits.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. An activated carbon preparation apparatus, comprising, from top to bottom, a raw material mixing tank (1), a fluidized bed carbonization furnace (2), an activator mixing and drying furnace (3), and an activation furnace (4), characterized in that, The activator mixing and drying furnace (3) is equipped with a movably installed filter plate (31), a first stirring mechanism (5) located above the filter plate (31), and a vibration mechanism (7) located below the filter plate (31). The top periphery of the activator mixing and drying furnace (3) is equipped with an activator adding mechanism (6) connected to its furnace space. One of the power output ends of the first stirring mechanism (5) is linked with the activator adding mechanism (6) to periodically drive the discharge port of the activator adding mechanism (6) to open and close, thereby completing the periodic intermittent addition of activator. The other power end of the first stirring mechanism (5) is linked with the vibration mechanism (7) to periodically drive the vibration mechanism (7) to vibrate the filter plate (31).

2. The activated carbon preparation apparatus according to claim 1, characterized in that, The first stirring mechanism (5) includes a first stirring shaft (51) that runs horizontally through the activator mixing and drying oven (3) and a first motor (52) that is connected to the first stirring shaft (51). The two ends of the first stirring shaft (51) extend outside the activator mixing and drying oven (3) to form its linkage part, and are respectively linked with the activator adding mechanism (6) and the vibration mechanism (7).

3. The activated carbon preparation apparatus according to claim 2, characterized in that, The activator adding mechanism (6) includes an activator adding hopper (61), a discharge port opening and closing control bolt (62), a linkage cam (63), and a first spring (64). The activator adding hopper (61) has a discharge nozzle (611) connected to and fixed on the top periphery of the activator mixing and drying furnace (3). The discharge port opening and closing control bolt (62) has a "door" shaped structure, with an outer bolt plate (621) bent vertically downward at the outer end and an inner bolt plate (622) bent vertically downward at the inner end. A side opening (6211) is formed on the outer bolt plate (621) for the discharge nozzle (611) to pass through. The top of the activator mixing and drying furnace (3) is provided with a first sliding hole (32) for the inner bolt plate (622) to be movably assembled therein. The lower end of the inner bolt plate (622) can move up and down to contact and disengage from the mouth of the feeding nozzle (611) so that the mouth of the feeding nozzle (611) is exposed and closed. The first spring (64) is connected between the middle part of the bolt body of the feeding port opening and closing control bolt (62) and the top of the activator mixing and drying furnace (3). The linkage cam (63) is fixedly connected to the linkage part of the first stirring shaft (51), and the rim slides against the lower end of the outer bolt plate (621).

4. The activated carbon preparation apparatus according to claim 2, characterized in that, The vibration mechanism (7) includes a vertically arranged reciprocating slide bar (71), a horizontal connecting rod (72) fixed at the lower end of the reciprocating slide bar (71), a first ball (721) fixed at the inner end of the horizontal connecting rod (72), and a second ball (311) provided on the lower surface of the filter plate (31). The linkage part of the first stirring shaft (51) is provided with a bidirectional threaded groove (511). The upper end of the reciprocating slide bar (71) is connected to the bidirectional threaded groove (511). The side wall of the activator mixing and drying furnace (3) is provided with a second sliding hole for the horizontal connecting rod (72) to be movably assembled therein. The filter plate (31) vibrates and sieves in the dynamic reciprocating compression of the first ball (721) against the second ball (311).

5. The activated carbon preparation apparatus according to claim 1, characterized in that, The inner wall of the activator mixing and drying furnace (3) is provided with several ring-shaped baffle steps (312), the bottom of the filter plate (31) rests on the baffle steps (312), and a second spring (313) is connected between the baffle steps (312) and the bottom of the filter plate (31).

6. The activated carbon preparation apparatus according to claim 3, characterized in that, On one of the activator addition hoppers (61) corresponding to the first motor (52), there is a motor support arm (53) fixedly connected to the hopper body. The corresponding shaft end of the first stirring shaft (51) is rotatably connected to the lower end of the motor support arm (53). The first motor (52) is fixedly connected to the lower end of the motor support arm (53).

7. The activated carbon preparation apparatus according to claim 1, characterized in that, The connection channel between the raw material mixing tank (1) and the fluidized bed carbonization furnace (2) is provided with a first rotary valve (9), the fluidized bed carbonization furnace (2) is provided with a second rotary valve (91), the activation furnace (4) is provided with a third rotary valve (92), the fluidized bed carbonization furnace (2) is connected to a first nitrogen addition pipe (21) above the second rotary valve (91), and the activation furnace (4) is connected to a second nitrogen addition pipe (41) above the third rotary valve (92).

8. A method for preparing activated carbon based on the apparatus described in claims 1 to 7, characterized in that, Including the following steps: Step 1: Raw material pretreatment. The sludge is dewatered and dried, crushed and sieved to obtain sludge powder with a particle size of 80-120 mesh. The biomass is sieved in the same way to obtain biomass powder with a particle size of 80-120 mesh. Step 2: Mixing raw materials. According to the weight ratio, the sludge powder and biomass powder obtained in Step 1 are mixed in a ratio of sludge powder:biomass powder = 1:1, and then put into the raw material mixing tank (1) for thorough stirring and mixing. Step 3, carbonization treatment: The raw materials obtained by thorough mixing in step 2 are fed into the fluidized bed carbonization furnace (2) to cause carbonization reaction in the raw materials and form carbonized material; Step 4: Activator mixing. The carbonized material obtained in step 3 is fed into the activator mixing and drying furnace (3). Then, liquid activator is periodically added into the activator mixing and drying furnace (3) through the activator adding mechanism (6). At the same time, the carbonized material and activator are stirred and mixed by the first stirring mechanism (5). The filter plate (31) is periodically vibrated by the vibration mechanism (7) to screen out carbon powder with uniform particle size. The solid-liquid ratio is 1:3 for carbonized material and activator. Step 5: Carbon powder activation treatment, so that the carbon powder screened in step 4 falls into the activation furnace (4), nitrogen gas is introduced into the activation furnace (4), and the temperature is heated to 750℃~850℃ for high-temperature activation for 50~70min to obtain activated carbon with uniform particle size.

9. The method for preparing activated carbon according to claim 8, characterized in that, The activator is a KOH solution.

10. The method for preparing activated carbon according to claim 8, characterized in that, In step 3, nitrogen gas is also introduced into the fluidized bed carbonization furnace (2) during the carbonization reaction of the raw materials.

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