A system and method for the production of supercapacitor carbon

Abstract

The application discloses a preparation system and method of supercapacitor carbon, and the system comprises a pyrolysis and pre-activation module, a gasification and activation module and a post-processing module; the pyrolysis and pre-activation module comprises a pyrolysis reactor; the gasification and activation module comprises a gasification furnace and an acid pickling tank; a feeding inlet of the post-processing module is communicated with a second discharging pipeline, and a discharging outlet of the post-processing module is used for discharging the supercapacitor carbon after post-processing; the post-processing module is further provided with a flue gas inlet communicated with a sandwich space. The mixture of biomass raw materials and chemical activators is conveyed to the pyrolysis reactor to generate biochar and pyrolysis gas through pyrolysis and pre-activation reaction; the biochar and the pyrolysis gas are conveyed to the gasification furnace to generate crude capacitive carbon and crude combustible gas through gasification and activation reaction; the crude capacitive carbon is subjected to acid pickling through the acid pickling tank to obtain capacitive carbon, and finally, the supercapacitor carbon is obtained through post-processing. The preparation system and method can improve the performance of the supercapacitor carbon and save resources.

Description

Technical Field

[0001] This invention specifically relates to a system and method for preparing carbon for supercapacitors. Background Technology

[0002] Supercapacitors, as a novel energy storage device, have shown broad application prospects in new energy vehicles, smart grids, and rail transportation due to their advantages such as high power density, fast charging and discharging speed, and long cycle life. Electrode materials are the core component of supercapacitors, and their performance directly determines the overall performance of the device. Among numerous electrode materials, carbon-based supercapacitor carbon, with its high specific surface area, has become the mainstream material for research and application due to its wide availability, good chemical stability, and excellent conductivity.

[0003] Currently, the preparation methods for supercapacitor carbon are mainly divided into two categories: physical activation and chemical activation. Physical activation typically involves carbonizing the carbon source (such as coconut shells or coal) first, then etching it at high temperatures (800-1000℃) using gases such as water vapor or carbon dioxide as activators to form pores. This method is simple and produces little pollution, but the resulting carbon material has a relatively low specific surface area and is predominantly microporous, limiting the rapid transport of ions in the electrolyte and resulting in poor rate performance. Chemical activation involves incorporating chemical activators (such as KOH, NaOH, or ZnCl2) into the carbon source precursor, followed by a one-step pyrolysis activation under an inert atmosphere. This method produces carbon materials with a high specific surface area and controllable pore size distribution, but this process usually requires temperatures above 700℃. Maintaining this high-temperature environment currently relies on external power supplies, resulting in enormous energy consumption. Furthermore, the single chemical activation method requires high purity of the precursor. These factors contribute to the high cost of supercapacitor carbon, limiting its large-scale application.

[0004] On the other hand, biomass, as a widely available, renewable, and low-cost carbon source, has always been a research hotspot in the field of energy and chemical engineering for its high-value utilization. Pyrolysis gasification technology is one of the main technical routes for converting biomass into syngas, bio-oil, and biochar. However, most traditional technologies adopt a one-step biomass gasification method, which completes the drying, pyrolysis, oxidation, and reduction processes of biomass in a single gasifier. The temperature ranges required for these processes are different, and a single gasifier cannot precisely control the temperature required for these processes. This results in the produced gas containing a large amount of tar, and the produced biochar is usually of low quality, with underdeveloped pore structure and high ash content.

[0005] Therefore, there are obvious contradictions and gaps in the existing technology: on the one hand, the preparation of high-performance supercapacitor carbon faces bottlenecks such as high raw material costs, high process energy consumption, and environmental pollution risks; on the other hand, the massive biomass resources can only achieve low-value energy utilization through traditional gasification technology, and its solid products (biochar) are not effectively utilized as resources. Moreover, traditional one-step biomass gasification technology still faces the severe challenge of high tar content in gasification gas. How to integrate biomass conversion technology with high-end carbon material manufacturing technology across fields and develop a green new process that can simultaneously solve the problems of high-performance supercapacitor carbon production cost and high-value utilization of biomass has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of poor performance, high energy consumption and complex production process of supercapacitor carbon produced in the prior art, and to provide a supercapacitor carbon preparation system and method.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] This invention provides a supercapacitor carbon preparation system, which includes a pyrolysis and pre-activation module, a gasification and activation module, and a post-processing module;

[0009] The pyrolysis and pre-activation module includes a pyrolysis reactor. A feed section and a discharge section are provided on the pyrolysis reactor along the conveying direction of the biomass raw material to be processed. The pyrolysis reactor includes an inner cylinder and an outer cylinder arranged coaxially, forming a space between the inner cylinder and the outer cylinder. A flue gas outlet is also provided on the wall of the outer cylinder. The feed section is used to convey the biomass to be processed into the inner cylinder of the pyrolysis reactor. The discharge section includes a first discharge pipe for discharging the pyrolyzed and pre-activated biochar. The pyrolysis reactor also has a first exhaust pipe for discharging the pyrolysis and pre-activation pyrolysis gas.

[0010] The gasification and activation module includes a gasifier and an acid washing tank. The gasifier has a feed inlet at the top, which is connected to the first discharge pipe. An air inlet is also located above the side wall of the gasifier, and it is connected to the first exhaust pipe. A second exhaust pipe is located below the side wall of the gasifier to discharge the crude combustible gas produced in the gasifier. The acid washing tank is located at the bottom of the gasifier, and its internal space is connected to the internal chamber of the gasifier, allowing the crude capacitive carbon obtained in the gasifier to fall directly into the acid washing tank. A second discharge pipe is located below the acid washing tank to discharge the acid-washed capacitive carbon.

[0011] The feed inlet of the post-processing module is connected to the second discharge pipe, and the discharge outlet of the post-processing module is used to discharge the post-processed supercapacitor carbon; the post-processing module is also provided with a flue gas inlet, and the flue gas inlet and the flue gas outlet are connected to the interlayer space through a first flue gas emission pipe.

[0012] In this scheme, pyrolysis and pre-activation reactions are carried out in a pyrolysis reactor, while gasification and activation reactions are carried out in a gasifier. By separating these different reactions into two separate devices, the traditional one-stage gasification process is broken down, allowing for better reaction kinetic balance between the different reaction processes. This improves the quality of the reaction products, reduces the tar content in the crude gas, and yields higher-quality reaction products, thus enhancing the performance of the supercapacitor carbon. Connecting the pickling tank directly to the gasifier simplifies the equipment process, eliminating the need for a separate pickling device. Simultaneously, the liquid in the pickling tank forms a liquid seal, preventing gas from the gasifier from entering the post-treatment device. The flue gas generated in the pyrolysis reactor is directly used in the post-treatment device, saving resources and reducing energy consumption.

[0013] Preferably, the preparation system further includes a pretreatment module for crushing and mixing biomass raw materials. The pretreatment module includes a crusher and a mixer. The bottom of the crusher is connected to the top of the mixer through a third discharge pipe, and the bottom of the mixer is connected to the feed section of the pyrolysis reactor through a fourth discharge pipe.

[0014] In this scheme, by crushing and mixing the materials, the materials can react more fully when they enter the subsequent pyrolysis reactor, thereby improving the reaction efficiency.

[0015] Preferably, the gasifier has a grate at the bottom, which is located above the pickling tank. The grate is connected to the pickling tank by a material conveying channel. The grate includes a transmission mechanism and a powder cone. The transmission mechanism is electrically connected to the powder cone and is used to drive the powder cone to rotate. The powder cone is located inside the gasifier and above the material conveying channel. The upper surface of the powder cone is provided with air holes.

[0016] In this scheme, by setting a grate at the bottom, it serves as a container for receiving reactants and an inlet for introducing activators. In addition, the grate can also be used as a material conveying device to transport the crude activated carbon after reaction in the gasifier to the pickling tank. The grate setting simplifies the process flow and improves production efficiency.

[0017] Preferably, the outer cylinder of the pyrolysis reactor is further provided with an internal burner, and a gas inlet is provided above the internal burner;

[0018] In this solution, the built-in burner enables the reuse of fuel gas in the gasifier, saving resources and reducing energy consumption.

[0019] Preferably, the inner cylinder of the pyrolysis reactor is equipped with an agitator, which consists of several identical base plates and identical columns. The outer circumferential surface of the base plates is a regular hexagonal structure. The centers of the several base plates are located on the central axis of the inner cylinder and are arranged sequentially opposite each other along a direction perpendicular to the axis of the inner cylinder. The columns connect the vertices of the regular hexagonal structures of the several base plates and are parallel to the axis of the inner cylinder. The agitator is fitted to the inner cylinder and is used to clean the material adhering to the inner wall of the pyrolysis reactor. The pyrolysis reactor is a rotary kiln.

[0020] In this scheme, the stirring component is in direct contact with the inner wall of the cylinder. By utilizing the relative friction with the inner wall of the rotary kiln, the coking on the inner wall is removed, thereby cleaning the inner cylinder wall, stirring the solid bed, and increasing the heat exchange area of ​​the solid particles. This improves production efficiency, enhances the reaction effect of pyrolysis and pre-activation, and ultimately improves the quality of biochar and pyrolysis gas.

[0021] Preferably, the preparation system further includes a purification module for purifying the crude combustible gas. The purification module includes a hydrocyclone, a deacidifier, a high-temperature dust collector, an electrostatic precipitator, a gas-liquid separator, and a desulfurization tower connected in sequence by pipes. The air inlet of the hydrocyclone is connected to the gasifier through the second exhaust pipe, and the clean gas from the desulfurization tower is connected to the gas inlet of the built-in burner through a gas fan.

[0022] In this scheme, the purification device described above is used to purify the crude gas, and the purified clean gas is directly reused in the pyrolysis reactor, thus realizing resource recycling, saving resources, and reducing energy consumption.

[0023] Preferably, the post-processing module includes a washing tank and a drying kiln. The inlet of the washing tank is connected to the pickling tank through the second discharge pipe, and the outlet of the washing tank is connected to the inlet of the drying kiln through the fifth discharge pipe. A flue gas emission outlet is provided above the drying kiln.

[0024] This invention also provides a method for preparing supercapacitor carbon, which uses the above-mentioned supercapacitor carbon preparation system and includes the following steps:

[0025] S1. A mixture of biomass raw materials and chemical activators is transported to the pyrolysis reactor for pyrolysis and pre-activation reaction to generate biochar and pyrolysis gas;

[0026] S2. The biochar and the pyrolysis gas are fed to the gasifier for gasification and activation reaction to generate crude capacitor char and crude combustible gas; the crude capacitor char is then acid-washed in the acid washing tank to obtain capacitor char.

[0027] S3. The deashed capacitor carbon is transported to the post-processing module, and supercapacitor carbon is obtained after post-processing. The hot air used in the post-processing process comes from the flue gas provided by the interlayer space of the pyrolysis reactor.

[0028] Preferably, the biomass raw material is one or more of straw, coconut shell, wood chips and rice husk, the particle size of the biomass raw material is 2-3 cm, and the initial moisture content of the biomass raw material is not greater than 50%.

[0029] In this scheme, biomass raw materials are widely available and easy to obtain, which greatly reduces production costs. By setting the particle size and initial moisture content of the biomass raw materials, the efficiency and effectiveness of subsequent pyrolysis and pre-activation reactions of the biomass raw materials are improved.

[0030] Preferably, the mass ratio of the biomass raw material to the chemical activator in the mixture is 1:(1~4); the chemical activator is potassium hydroxide.

[0031] Preferably, the reaction temperature in the pyrolysis reactor is 400-550°C, and the reaction time of the mixture of biomass raw material and chemical activator in the pyrolysis reactor is 1.2-2 hours.

[0032] In this scheme, by setting the reaction temperature and reaction time of biomass raw materials in the thermal reactor, the reaction effect of biomass raw materials during pyrolysis and preactivation is improved, thereby improving the quality of the reaction products biochar and pyrolysis gas.

[0033] Preferably, the reaction temperature in the gasifier is 800-1000℃, and the reaction time between the biochar and the pyrolysis gas in the gasifier is 40-80 minutes.

[0034] In this scheme, by setting the reaction temperature and reaction time of biochar and pyrolysis gas in the gasifier, the reaction effect of biochar and pyrolysis gas during gasification and activation is improved, thereby improving the quality of the reaction products crude pyrocarbon and crude combustible gas and reducing the tar content in the crude combustible gas.

[0035] Preferably, in the gasification and activation reaction, the raw material fed to the gasifier also includes water vapor; the temperature of the water vapor is 250-300℃, and the amount of water vapor entering the gasifier is 1-3 times the mass of the biomass raw material, wherein the mass of the biomass raw material refers to the mass of the biomass raw material in a dry state.

[0036] In this scheme, by setting the temperature and air intake of water vapor, the reaction effect during biochar activation is improved, thereby improving the quality of the reaction product, crude capacitive carbon.

[0037] The positive and progressive effects of this invention are as follows:

[0038] (1) This system and method break down the traditional one-stage gasification process, so that different reaction processes can achieve better reaction kinetic balance, thereby greatly eliminating tar and improving the cleanliness of crude gas.

[0039] (2) This system and method use biomass, which is more abundant and easier to obtain, as raw material, which greatly reduces the production cost of supercapacitor carbon.

[0040] (3) The energy required for the pre-activation, activation and drying of supercapacitor carbon in this system and method is generated internally by the system and does not require external energy supply, which greatly reduces the energy consumption of supercapacitor carbon production.

[0041] (4) The drying and pre-activation steps in this system and method are completed in a single device, as are the gasification, activation and acid washing steps. Compared with traditional methods, the production process and equipment of this supercapacitor carbon are simpler.

[0042] (5) During the activation stage, the carbon dioxide generated by synchronous gasification can form a mixed activator with high-temperature water vapor, which is beneficial to the activation and formation of different pore sizes inside the capacitor carbon. This system and method cover both physical and chemical activation methods. The synergistic effect of multiple activation methods is beneficial to improving the pore volume and multi-pore size distribution of the capacitor carbon, thereby improving the quality of the capacitor carbon. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the supercapacitor carbon preparation system in Example 1.

[0044] Figure 2 This is a schematic diagram of the agitator in Example 1.

[0045] Figure 3 The image shows the BET analysis chart of the carbon supercapacitor in Example 1.

[0046] Figure 4 This is a carbon SEM analysis image of the supercapacitor in Example 1.

[0047] Explanation of reference numerals in the attached figures:

[0048] Preprocessing Module 1

[0049] Crusher 1.1

[0050] 1.2 Mixer

[0051] Pyrolysis and Pre-activation Module 2

[0052] Feeding section 2.1

[0053] Mezzanine space 2.2

[0054] 2.3 Agitator component

[0055] Built-in burner 2.4

[0056] Discharge section 2.5

[0057] Gasification and activation module 3

[0058] Gasifier 3.1

[0059] 3.2 grate

[0060] Pickling tank 3.3

[0061] Post-processing module 4

[0062] 4.1 Water washing tank

[0063] Drying kiln 4.2

[0064] Purification Module 5

[0065] Hydrocyclone 5.1,

[0066] Deacidifier 5.2,

[0067] High-temperature dust collector 5.3

[0068] 5.4 Swirl heat exchanger

[0069] Primary heat exchanger 5.5

[0070] Secondary heat exchanger 5.6

[0071] Electrostatic precipitator 5.7

[0072] Gas-liquid separator 5.8

[0073] Desulfurization tower 5.9

[0074] Gas-fired blower 5.10 Detailed Implementation

[0075] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0076] Example 1

[0077] This embodiment provides a system for preparing supercapacitor carbon, such as... Figure 1 As shown: The system includes a pretreatment module 1, a pyrolysis and preactivation module 2, a gasification and activation module 3, a posttreatment module 4, and a purification module 5.

[0078] The pretreatment module 1 includes a crusher 1.1 and a mixer 1.2. The bottom of the crusher 1.1 and the top of the mixer 1.2 are connected through a third discharge pipe. The bottom of the mixer 1.2 is connected to the feed section 2.1 of the pyrolysis reactor through a fourth discharge pipe. The pretreatment module 1 is used to crush and mix biomass raw materials.

[0079] The pyrolysis and pre-activation module 2 includes a pyrolysis reactor. A feed section 2.1 and a discharge section 2.5 are provided on the pyrolysis reactor along the conveying direction of the biomass raw material to be processed. The pyrolysis reactor includes an inner cylinder and an outer cylinder arranged coaxially, forming a sandwich space 2.2 between the inner and outer cylinders. A flue gas outlet is also provided on the wall of the outer cylinder. The feed section 2.1 is used to convey the biomass to be processed to the inner cylinder of the pyrolysis reactor. The discharge section 2.5 includes a first discharge pipe for discharging the pyrolyzed and pre-activated biochar. A first exhaust pipe is also provided on the pyrolysis reactor for discharging the pyrolysis and pre-activation pyrolysis gas. An internal burner 2.4 is also provided on the wall of the outer cylinder of the pyrolysis reactor, and a gas inlet is provided above the internal burner 2.4.

[0080] In this embodiment, the pyrolysis reactor is a rotary kiln. An agitator 2.3 is installed inside the inner cylinder of the rotary kiln. The agitator 2.3 consists of several identical base plates and identical columns. The outer circumference of the base plates is a regular hexagonal structure. The centers of the base plates are located on the central axis of the inner cylinder and are arranged sequentially and opposite to each other along a direction perpendicular to the axis of the inner cylinder. The columns connect to the vertices of the regular hexagonal structures of the base plates and are parallel to the axis of the inner cylinder. The agitator 2.3 is fitted into the inner cylinder and is used to clean the material adhering to the inner wall of the pyrolysis reactor. The purpose of the agitator 2.3 is to simultaneously clean the inner cylinder wall, stir the solid bed, and increase the heat exchange area of ​​the solid particles during rotation. The mixed materials undergo simultaneous drying, pyrolysis, and pre-activation in the rotary kiln, greatly simplifying the traditional process for preparing capacitor carbon.

[0081] The gasification and activation module 3 includes a gasifier 3.1 and an acid washing tank 3.3. The gasifier 3.1 has a feed inlet at the top, which connects to a first discharge pipe. An air inlet is also located on the upper side wall of the gasifier 3.1, connecting to a first exhaust pipe. A second exhaust pipe is located below the side wall of the gasifier 3.1 to discharge the crude combustible gas produced in the gasifier 3.1 after reaction. A grate 3.2 is located at the bottom of the gasifier 3.1, above the acid washing tank 3.3. A material conveying channel connects the grate 3.2 and the acid washing tank 3.3. The grate 3.2 includes a transmission mechanism and a powder... The material cone and the transmission mechanism are electrically connected to the powder cone to drive its operation. The powder cone is located inside the gasifier 3.1 and above the material conveying channel. The upper surface of the powder cone has pores. The pickling tank 3.3 is located at the bottom of the gasifier 3.1, and its internal space is connected to the internal chamber of the gasifier 3.1, so that the crude capacitor carbon obtained in the gasifier 3.1 falls directly into the pickling tank 3.3. A second discharge pipe is provided below the pickling tank 3.3 to discharge the pickled capacitor carbon.

[0082] The post-processing module 4 includes a washing tank 4.1 and a drying kiln 4.2. The inlet of the washing tank 4.1 is connected to the pickling tank 3.3 through a second discharge pipe, and the outlet of the washing tank 4.1 is connected to the inlet of the drying kiln 4.2 through a fifth discharge pipe. The drying kiln 4.2 has a flue gas exhaust outlet at the top of its tail end and a super activated carbon exhaust outlet at the bottom of its tail end. The drying kiln 4.2 also has a flue gas inlet, and the flue gas inlet and the flue gas outlet are connected to the interlayer space 2.2 through a first flue gas exhaust pipe.

[0083] The preparation system also includes a purification module 5 for purifying the crude combustible gas. The purification module 5 includes a cyclone separator 5.1, an acid remover 5.2, a high-temperature dust collector 5.3, a cyclone heat exchanger 5.4, a primary heat exchanger 5.5, a secondary heat exchanger 5.6, an electrostatic precipitator 5.7, a gas-liquid separator 5.8, and a desulfurization tower 5.9 connected in sequence by pipes to achieve the gradual purification of the crude gas. The air inlet of the cyclone separator 5.1 is connected to the gasifier 3.1 through a second exhaust pipe, and the clean gas from the desulfurization tower 5.9 is connected to the gas inlet of the built-in burner 2.4 through a gas blower 5.10.

[0084] The specific process for preparing supercapacitor carbon using the above-mentioned supercapacitor carbon preparation system is as follows:

[0085] Biomass raw materials are conveyed to crusher 1.1 via belt conveyors and other equipment for crushing. The bottom of crusher 1.1 is connected to mixer 1.2. Mixer 1.2 has a paddle structure inside. The crushed biomass particles and potassium hydroxide powder are simultaneously fed into mixer 1.2 for mixing. The uniformly mixed material is further fed into rotary kiln through feed section 2.1. The main body of rotary kiln is externally heated, and the heating source is the gas produced by the system itself. The gas is burned by the built-in burner 2.4 on the rotary kiln to heat the main body of the rotary kiln. The main body of rotary kiln is provided with a jacketed space 2.2. The hot flue gas generated by the combustion of the built-in burner 2.4 flows from the tail end of the jacketed kiln to the head end and is discharged to the post-processing module 4. The rotary kiln is an oxygen-free environment. The tail end is provided with discharge section 2.5. The pyrolysis gas and biochar generated by the pyrolysis and pre-activation reaction in the rotary kiln are further transported to gasification and activation system 3.

[0086] In this embodiment, the feeding unit 2.1 is a screw conveyor.

[0087] The gasification and activation system 3 includes a typical downdraft biomass gasifier 3.1. Biochar generated after the rotary kiln reaction falls into the gasifier 3.1 through the central opening at the top. Pyrolysis gas enters the gasifier 3.1 through a pipe from the upper part of the furnace chamber, designed as a swirling flow. The grate 3.2 is the discharge structure of the gasifier 3.1, mainly composed of a transmission mechanism and a powder cone. The distribution cone is located inside the gasifier 3.1 and directly contacts the solid bed. The upper surface of the distribution cone has 8mm diameter pores, serving as the inlet for the activator steam. The activated carbon produced during activation is discharged into the acid washing tank 3.3 connected to the bottom of the gasifier 3.1 for deashing. After acid washing, the activated carbon enters the washing tank 4.1, where the resulting activated carbon mixture is washed with deionized water until neutral. After washing, the solid material is transported to the drying kiln 4.2 for drying. The drying method is hot air drying, and the hot air source is the flue gas generated by combustion in the built-in burner 2.4 on the rotary kiln. After drying, it becomes the supercapacitor carbon produced by this process. The crude gas produced by the gasification and activation system 3 passes through the following stages in sequence: coarse desaturation by the hydrocyclone 5.1, dechlorination by the acid remover 5.2, fine impurity removal by the high-temperature dust collector 5.3, primary decoking by the hydrocyclone heat exchanger 5.4, secondary decoking by the primary heat exchanger 5.5, tertiary decoking by the secondary heat exchanger 5.6, tar removal by the electrostatic precipitator 5.7, moisture removal by the gas-liquid separator 5.8, and desulfurization tower 5.9 for sulfur removal. This process gradually purifies the crude gas. Finally, the purified gas is transported to the built-in burner 2.4 for combustion and heating by the gas blower 5.10.

[0088] In this embodiment, the rotary kiln body has a diameter of 1.5m and a cylinder length of 10m, and the gasifier 3.1 has an inner diameter of 1.2m and a height of 8m.

[0089] This embodiment also provides a method for preparing supercapacitor carbon, which is carried out using the supercapacitor carbon preparation system of this embodiment. The biomass raw material used in this embodiment is coconut shell with a moisture content of 27%, and the activator introduced into the gasifier 3.1 is high-temperature steam. The specific preparation method in this embodiment is as follows:

[0090] S1. The mixture of biomass raw materials and potassium hydroxide powder is transported to a rotary kiln for pyrolysis and pre-activation reaction to generate biochar and pyrolysis gas.

[0091] S2, biochar and the pyrolysis gas are fed to gasifier 3.1 for gasification and activation reaction to generate crude capacitor char and crude combustible gas; the crude capacitor char is then acid-washed in acid washing tank 3.3 to obtain capacitor char.

[0092] S3. The deashed capacitor carbon is transported to the post-processing module 4 and post-processed to obtain supercapacitor carbon. The hot air used in the post-processing process comes from the flue gas provided by the interlayer space 2.2 of the rotary kiln.

[0093] The mass ratio of coconut shell to potassium hydroxide powder is 1:2.5; the feed rate of the mixture in the rotary kiln is 500 kg / h, the rotary kiln speed is adjusted to 1.5 rpm, the material residence time is 1.41 h, and the average temperature in the rotary kiln is 518℃; the average temperature in the gasifier 3.1 is about 910℃, the temperature of the high-temperature steam introduced is 270℃, and the introduction rate is 150 kg / h.

[0094] The supercapacitor carbon prepared by the above method, when subjected to pyrolysis and pre-activation reactions in a rotary kiln, produces approximately 350 m³ of pyrolysis gas. 3 / h, producing approximately 8100m³ of flue gas. 3 / h; During the gasification and activation reaction in gasifier 3.1, the amount of crude gas produced is approximately 710m³ / h. 3 The generated crude gas, after being treated by the gas purification system 5, has a tar content of 37 mg / Nm³ / h. 3 .

[0095] The final yield of supercapacitor carbon was approximately 30 kg / h. Electrochemical performance tests were performed on the supercapacitor carbon produced in this example, and the results are as follows: Figure 3 and Figure 4 As shown, the measured specific surface area is 1947 m². 2 / g, the three-electrode capacitance at a current density of 1A / g is 170F / g.

[0096] Example 2

[0097] The system used in this embodiment is the same as that in Embodiment 1, but the process parameters that differ from those in Embodiment 1 are as follows: This embodiment uses wheat straw with a moisture content of 20%, the mixing ratio of straw and potassium hydroxide powder is 1:2, the feed rate of the mixture in the rotary kiln is 400 kg / h, the rotary kiln speed is adjusted to 1.5 rpm, the material residence time is 1.67 h, the average temperature in the rotary kiln is 500℃, the average temperature in the gasifier 3.1 is about 980℃, the temperature of the high-temperature steam introduced is 280℃, and the introduction rate is 200 kg / h.

[0098] The supercapacitor carbon prepared by the above method, when subjected to pyrolysis and pre-activation reactions in a rotary kiln, produces approximately 280 m³ of pyrolysis gas. 3 / h, producing approximately 7600m³ of flue gas. 3 / h; During the gasification and activation reaction in gasifier 3.1, the amount of crude gas produced is approximately 650m³ / h. 3 The generated crude gas, after being treated by the gas purification system 5, has a tar content of 31 mg / Nm³ / h. 3 .

[0099] The final yield of supercapacitor carbon was approximately 36 kg / h. Electrochemical performance tests were performed on the supercapacitor carbon produced in this example, and the measured specific surface area was 1640 m². 2 / g, the three-electrode capacitance at a current density of 1A / g is 134F / g.

[0100] Example 3

[0101] The system used in this embodiment is the same as that in Embodiment 1, but the process parameters that differ from those in Embodiment 1 are as follows: This embodiment uses wood chips with a moisture content of 35%, the mixing ratio of wood chips and potassium hydroxide powder is 1:3, the feed rate of the mixture in the rotary kiln is 600 kg / h, the rotary kiln speed is adjusted to 1.5 rpm, the material residence time is 1.5 h, the average temperature in the rotary kiln is 490℃, the average temperature in the gasifier 3.1 is about 955℃, the temperature of the high-temperature steam introduced is 280℃, and the introduction rate is 300 kg / h.

[0102] The supercapacitor carbon prepared by the above method, when subjected to pyrolysis and pre-activation reactions in a rotary kiln, produces approximately 265 m³ of pyrolysis gas. 3 / h, producing approximately 6600m³ of flue gas. 3 / h; During the gasification and activation reaction in gasifier 3.1, the amount of crude gas produced is approximately 612m³. 3 The generated crude gas, after being treated by the gas purification system 5, has a tar content of 35 mg / Nm³ / h. 3 .

[0103] The final yield of supercapacitor carbon was approximately 41 kg / h. Electrochemical performance tests were performed on the supercapacitor carbon produced in this example, and the measured specific surface area was 1840 m². 2 / g, the three-electrode capacitance at a current density of 1A / g is 151F / g.

[0104] Comparative Example 1:

[0105] The system used in this embodiment is the same as that in Example 1. Other process parameters are kept unchanged in Example 1, but the addition of potassium hydroxide activator is omitted, i.e., the chemical activation process is eliminated. Supercapacitor carbon is prepared solely through physical activation by high-temperature steam in gasifier 3.1. The results show that the final yield of supercapacitor carbon is 67 kg / h (product yield approximately 13.4%), and its specific surface area is 920 m². 2 The three-electrode capacitance at a current density of 1 A / g is 71 F / g. The results indicate that a single physical activation method can improve the yield of supercapacitor carbon, but it severely affects the quality and performance of the supercapacitor carbon.

[0106] The specific process parameters and effect parameters for each embodiment are shown in the table below:

[0107]

[0108] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A system for preparing supercapacitor carbon, characterized in that, The preparation system includes a pyrolysis and pre-activation module, a gasification and activation module, and a post-processing module; The pyrolysis and pre-activation module includes a pyrolysis reactor. A feed section and a discharge section are provided on the pyrolysis reactor along the conveying direction of the biomass raw material to be processed. The pyrolysis reactor includes an inner cylinder and an outer cylinder arranged coaxially, forming a space between the inner cylinder and the outer cylinder. A flue gas outlet is also provided on the wall of the outer cylinder. The feed section is used to convey the biomass to be processed into the inner cylinder of the pyrolysis reactor. The discharge section includes a first discharge pipe for discharging the pyrolyzed and pre-activated biochar. The pyrolysis reactor also has a first exhaust pipe for discharging the pyrolysis and pre-activation pyrolysis gas. The gasification and activation module includes a gasifier and an acid washing tank. The gasifier has a feed inlet at the top, which is connected to the first discharge pipe. An air inlet is also located above the side wall of the gasifier, and it is connected to the first exhaust pipe. A second exhaust pipe is located below the side wall of the gasifier to discharge the crude combustible gas produced in the gasifier. The acid washing tank is located at the bottom of the gasifier, and its internal space is connected to the internal chamber of the gasifier, allowing the crude capacitive carbon obtained in the gasifier to fall directly into the acid washing tank. A second discharge pipe is located below the acid washing tank to discharge the acid-washed capacitive carbon. The feed inlet of the post-processing module is connected to the second discharge pipe, and the discharge outlet of the post-processing module is used to discharge the post-processed supercapacitor carbon; the post-processing module is also provided with a flue gas inlet, and the flue gas inlet and the flue gas outlet are connected to the interlayer space through a first flue gas emission pipe.

2. The supercapacitor carbon preparation system as described in claim 1, characterized in that, The preparation system also includes a pretreatment module for crushing and mixing biomass raw materials. The pretreatment module includes a crusher and a mixer. The bottom of the crusher and the top of the mixer are connected through a third discharge pipe. The bottom of the mixer is connected to the feed section of the pyrolysis reactor through a fourth discharge pipe.

3. The supercapacitor carbon preparation system as described in claim 1, characterized in that, The gasifier has a grate at the bottom, which is located above the pickling tank. The grate is connected to the pickling tank by a material conveying channel. The grate includes a transmission mechanism and a powder cone. The transmission mechanism is electrically connected to the powder cone and is used to drive the powder cone to rotate. The powder cone is located inside the gasifier and above the material conveying channel. The upper surface of the powder cone is provided with air holes.

4. The supercapacitor carbon preparation system as described in claim 1, characterized in that, An internal burner is also provided on the outer cylinder wall of the pyrolysis reactor, and a gas inlet is provided above the internal burner; And / or, the inner cylinder of the pyrolysis reactor is provided with an agitating component, which is composed of several identical bottom plates and identical columns. The outer circumferential surface of the bottom plate is a regular hexagonal structure. The center positions of the several bottom plates are located on the central axis of the inner cylinder and are arranged sequentially opposite each other in a direction perpendicular to the axis of the inner cylinder. The columns connect the vertices of the regular hexagonal structure of the several bottom plates. The columns are parallel to the axis of the inner cylinder. The agitating component is fitted to the inner cylinder and is used to clean the material adhering to the inner wall of the pyrolysis reactor. And / or, the pyrolysis reactor is a rotary kiln.

5. The supercapacitor carbon preparation system as described in claim 4, characterized in that, The preparation system also includes a purification module for purifying the crude combustible gas. The purification module includes a hydrocyclone, a deacidifier, a high-temperature dust collector, an electrostatic precipitator, a gas-liquid separator, and a desulfurization tower connected in sequence by pipes. The air inlet of the hydrocyclone is connected to the gasifier through the second exhaust pipe, and the clean gas from the desulfurization tower is connected to the gas inlet of the built-in burner through a gas fan.

6. The supercapacitor carbon preparation system as described in claim 1, characterized in that, The post-processing module includes a washing tank and a drying kiln. The inlet of the washing tank is connected to the pickling tank through the second discharge pipe, and the outlet of the washing tank is connected to the inlet of the drying kiln through the fifth discharge pipe. A flue gas emission outlet is provided above the drying kiln.

7. A method for preparing supercapacitor carbon, characterized in that, It is carried out using the supercapacitor carbon preparation system as described in any one of claims 1 to 6, and includes the following steps: S1. The mixture of biomass raw materials and chemical activator is transported to the pyrolysis reactor for pyrolysis and pre-activation reaction to generate biochar and pyrolysis gas. S2. The biochar and the pyrolysis gas are fed to the gasifier for gasification and activation reaction to generate crude capacitor char and crude combustible gas; the crude capacitor char is then acid-washed in the acid washing tank to obtain capacitor char. S3. The deashed capacitor carbon is transported to the post-processing module, and supercapacitor carbon is obtained after post-processing. The hot air used in the post-processing process comes from the flue gas provided by the interlayer space of the pyrolysis reactor.

8. The method for preparing supercapacitor carbon as described in claim 7, characterized in that, The biomass raw material is one or more of straw, coconut shell, wood chips and rice husk, the particle size of the biomass raw material is 2-3 cm, and the initial moisture content of the biomass raw material is not greater than 50%.

9. The method for preparing supercapacitor carbon as described in claim 7, characterized in that, The mass ratio of the biomass raw material to the chemical activator in the mixture is 1:(1~4); And / or, the chemical activator is potassium hydroxide.

10. The method for preparing supercapacitor carbon as described in claim 7, characterized in that, The reaction temperature in the pyrolysis reactor is 400-550℃, and the reaction time of the mixture of biomass raw material and chemical activator in the pyrolysis reactor is 1.2-2h. And / or, the reaction temperature in the gasifier is 800-1000℃, and the reaction time of the biochar and the pyrolysis gas in the gasifier is 40-80 min; And / or, in the gasification and activation reaction, the raw material fed to the gasifier also includes steam; the temperature of the steam is 250-300°C, and the steam intake is 1-3 times the mass of the biomass raw material, wherein the mass of the biomass raw material refers to the mass of the biomass raw material in a dry state.

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