Apparatus and method for steam activation of porous carbon

Abstract

This invention discloses a steam activation device and method for porous carbon, relating to the field of inorganic non-metallic material preparation technology. The device includes a reactor body, a steam inlet system, a carrier gas inlet system, a pressure control system, and an electric heater. The fluidization branch of the carrier gas inlet system is connected to the bottom of the reactor body; the activation pipeline of the steam inlet system is connected to the pulse branch of the carrier gas inlet system, and the outlet of the injection pipe is connected to the side wall of the reactor body; the pressure control system is connected to the reactor body; and the electric heater is fitted onto the outside of the reactor body. This invention effectively prevents pipeline blockage and utilizes the intense disturbance and mixing of the bed material by the pulsed airflow. Pressurization through the pressure control system significantly improves the steam partial pressure and reaction rate, achieving highly efficient activation. The porous carbon product obtained by this invention has high purity, well-developed mesopores, and a high specific surface area, making it particularly suitable for high-end applications such as supercapacitor electrodes.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic material preparation technology, specifically to a steam activation device and method for porous carbon. Background Technology

[0002] Porous carbon materials, due to their high specific surface area, tunable pore size distribution, good chemical stability, and abundant pore structure, are widely used in key fields such as supercapacitors, lithium-ion batteries, catalyst supports, and gas adsorption and separation. Their performance largely depends on the pore structure, and the activation process is a crucial step in controlling this structure, especially in creating abundant pores. Among numerous activation methods, steam activation has become an important technology for the industrial production of high-performance porous carbon due to its advantages of being clean, pollution-free, relatively low-cost, and capable of generating abundant mesopores.

[0003] Currently, the most widely used steam activation equipment in industry is the rotary kiln. This equipment uses the rotation of the furnace body to tumble the materials, achieving a certain degree of mixing and heating. However, rotary kilns have significant technical limitations: their heat transfer efficiency is low, the temperature uniformity inside the furnace is poor, resulting in uneven activation of the materials; the gas-solid contact efficiency is limited, making it difficult to achieve precise control of activation; in addition, the capacity of a single unit is usually limited and it is not easy to scale up.

[0004] To overcome the shortcomings of rotary kilns, fluidized bed technology has been introduced into the steam activation process. Fluidized beds significantly enhance mixing and heat transfer efficiency through gas-solid fluidization, greatly improving the uniformity of activation. However, current fluidized bed technology suffers from problems such as low reaction efficiency, the easy introduction of metallic impurities through high-temperature mechanical stirring, and uneven gas-solid mixing in traditional fluidized beds.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] This invention proposes a steam activation device and method for porous carbon, aiming to achieve efficient, uniform, and high-purity porous carbon activation preparation without the need for mechanical stirring by combining pressurized operation, reactor main structure, and gas pulse mixing technology.

[0007] This invention is implemented as follows:

[0008] In a first aspect, the present invention provides a steam activation device for porous carbon, comprising a reactor body, a steam inlet system, a carrier gas inlet system, a pressure control system, and an electric heating furnace;

[0009] The carrier gas inlet system includes a carrier gas supply mechanism, a fluidization branch, and a pulse branch. The fluidization branch and the pulse branch are respectively connected to the carrier gas supply mechanism. The fluidization branch is connected to the bottom of the reactor body and is used to introduce fluidized carrier gas into the reactor body to establish a jet fluidized bed.

[0010] The steam intake system includes a steam generating mechanism, an activation pipeline, and an injection pipe. The steam generating mechanism is connected to the injection pipe through the activation pipeline. The pulse branch is connected to the activation pipeline for periodically introducing pulsed carrier gas into the activation pipeline. The outlet of the injection pipe is connected to the side wall of the reactor body.

[0011] The pressure control system is connected to the reactor body to control the pressure inside the reactor body; the electric heating furnace is fitted onto the outside of the reactor body.

[0012] In an optional embodiment, the pulse branch is provided with a pulse valve and a timing controller for controlling the opening and closing time of the pulse valve; the pulse frequency of the pulse valve is 1-20 times per minute, and the pulse time is 0.1-5 seconds.

[0013] And / or, the carrier gas intake system further includes a first preheating furnace, and the fluidization branch and the pulse branch are both connected to the first preheating furnace;

[0014] And / or, a buffer tank is also provided on the pulse branch, the buffer tank being located between the first preheating furnace and the pulse valve;

[0015] And / or, a first flow meter is provided on the fluidization branch.

[0016] In an optional embodiment, the carrier gas intake system further includes an activation branch, the carrier gas supply mechanism is connected to the activation branch, the activation branch is connected to the activation pipeline, and a second preheating furnace for heating the activation carrier gas and water vapor is provided on the activation pipeline.

[0017] In an optional embodiment, the reactor body consists of a reactor shell and an inverted conical gas distributor disposed at the bottom of the reactor shell, and the electric heating furnace is fitted outside the reactor shell.

[0018] In an optional embodiment, the bottom of the reactor shell is an inverted conical structure with a cone angle of 60°-150°; the inverted conical gas distributor is installed in a way that matches the inverted conical structure.

[0019] In an optional embodiment, the inverted conical gas distributor is an inverted conical metal sintered plate with an average pore size of 5-50 μm;

[0020] Alternatively, the inverted conical gas distributor is formed by the accumulation of chemically inert spherical particles at the bottom of the inverted conical reactor, wherein the spherical particles are alumina or silica spheres with a diameter of 3-15 mm.

[0021] In an optional embodiment, the pressure control system includes a back pressure valve and a pressure gauge, the back pressure valve being connected to an outlet pipe at the top of the reactor shell, and the pressure gauge being connected to the top of the reactor shell.

[0022] Secondly, the present invention provides a method for steam activation of porous carbon using the apparatus described in any of the above embodiments, comprising the following steps:

[0023] S1: The carbon material is loaded into the reactor body and sealed. Then, the fluidized carrier gas is introduced into the reactor body through the fluidized branch of the carrier gas inlet system to establish a jet fluidized bed.

[0024] S2: Start the electric heating furnace to heat the reactor body to 800-950℃, and adjust the pressure control system to maintain the absolute pressure inside the reactor body at 0.1~0.5MPa;

[0025] S3: Water vapor and activation carrier gas are introduced into the activation pipeline through the activation branch of the water vapor inlet system and the carrier gas inlet system. At the same time, the pulse branch is activated to periodically introduce pulse carrier gas into the activation pipeline to disturb and enhance the mixing of the jet fluidized bed. Under these conditions, the activation reaction is carried out for 1 to 5 hours.

[0026] S4: After the reaction is complete, stop the flow of steam and activation carrier gas, cool under the atmosphere of fluidized carrier gas, and take out the porous carbon product.

[0027] In an optional embodiment, the steam flow rate is 0.5~5 g steam / 1 g carbon·h;

[0028] And / or, the volumetric flow rate ratio of the water vapor and the activation carrier gas in the activation pipeline is 1:8-8:1;

[0029] And / or, the pulse carrier gas pressure introduced into the pulse branch is 0.1-0.3 MPa higher than the operating pressure inside the reactor body;

[0030] And / or, the carrier gas introduced into the carrier gas intake system is nitrogen, and the gas velocity is controlled to be 3 to 20 times the minimum fluidization gas velocity Umf;

[0031] The minimum fluidizing gas velocity Umf refers to the lowest apparent gas velocity required to transform a solid particle bed from a fixed bed state to an initial fluidized bed state in the system described in this invention. Physically, it is the critical velocity at which the upward drag force of the gas on the particles and the effective gravity (gravity minus buoyancy) of the particle group in the gas reach equilibrium.

[0032] Specifically, the minimum fluidizing gas velocity Umf is determined using the standard pressure drop-velocity method: given particle characteristics, bed geometry, and gas conditions, the apparent gas velocity U passing through the bed is gradually increased, and the corresponding bed pressure drop ΔP is recorded. ΔP is then plotted. The U-curve represents the pressure drop in the fixed bed stage that increases with flow velocity. The apparent gas velocity corresponding to the pressure drop reaching a stable plateau is defined as the minimum fluidizing gas velocity Umf. At this point, the bed pressure drop satisfies the relationship: ΔP≈(M / A). g, where M is the mass of the bed particles, A is the cross-sectional area of ​​the bed, and g is the gravitational acceleration, characterizing the balance between pressure drop and effective weight of particles per unit area.

[0033] In this invention, the minimum fluidizing gas velocity Umf is one of the core benchmark parameters for design and operation. Preferably, the apparent gas velocity of the carrier gas in the control system is (3 20)×Umf. Operating based on this benchmark is the key technology for achieving high-intensity gas-solid heat and mass transfer, efficient particle circulation and mixing, and efficient reaction in this invention.

[0034] In an optional embodiment, the carbon material is a carbon precursor with a particle size of 1-10 mm; the carbon precursor includes any one of coconut shell carbon, coal-based carbon, and resin carbon.

[0035] And / or, the specific surface area of ​​the porous carbon product is ≥1800 m² 2 / g, total pore volume is 0.8~1.5 cm³ 3 / g, and the mesopore ratio is ≥40%.

[0036] The present invention has the following beneficial effects:

[0037] The steam activation device and method for porous carbon provided by this invention form a fluidized bed within the reactor body through the fluidization branch of the carrier gas inlet system. A pressure control system is used to pressurize the reaction pressure within the reactor body, and the pulse branches of the steam inlet system and the carrier gas inlet system work together to facilitate the introduction of pulsed steam into the reactor body. In this invention, the pressurization operation significantly improves the partial pressure of steam and the reaction rate, increasing the activation efficiency by more than 30% compared to atmospheric pressure processes, effectively reducing energy consumption and reaction time. The use of pulsed airflow disturbance technology to replace mechanical stirring completely avoids impurity contamination caused by wear of metal stirrers at high temperatures, significantly improving product purity and meeting the high-purity application requirements of electrode materials, etc. Combined with directional pulsed airflow, it achieves thorough and uniform mixing of materials within the reactor, solving the dead zone and channeling problems present in traditional fluidized beds. The device has a simple structure, high reliability, and low maintenance cost, avoiding engineering challenges such as high-temperature dynamic sealing, making it easier for industrial scale-up and production. The prepared porous carbon product has a high specific surface area and a well-developed mesoporous structure, with a specific surface area ≥1800 m². 2 With a porosity of ≥45%, it exhibits excellent electrochemical performance in applications such as supercapacitors. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the steam activation device for porous carbon provided in Embodiments 1-5 of the present invention.

[0040] Icons: 100-Steam activation device for porous carbon; 110-Reactor body; 111-Reactor shell; 112-Inverted conical gas distributor; 113-Carrier gas inlet; 114-Steam inlet; 115-Feed port; 116-Outlet; 117-Thermocouple; 118-Metal filter column; 120-Steam inlet system; 121-Steam generation mechanism; 122-Injection pipe; 123-Quality control mechanism; 1 24-Second preheating furnace; 125-Activation pipeline; 130-Carrier gas inlet system; 131-Carrier gas supply mechanism; 132-Fluidization branch; 133-Pulse branch; 134-Pulse valve; 135-Second flow meter; 136-First flow meter; 137-Activation branch; 138-First preheating furnace; 139-Buffer tank; 140-Pressure control system; 141-Back pressure valve; 142-Pressure gauge; 150-Electric heating furnace. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. In addition to the various embodiments described in this section, the present invention can also be implemented in other different ways. Without departing from the spirit of this application, those skilled in the art can make corresponding improvements, modifications, and substitutions. Therefore, this application is not limited to the specific embodiments disclosed in this section.

[0042] Traditional fluidized beds suffer from low reaction efficiency and uneven gas-solid mixing. To further enhance mixing, some technical solutions introduce mechanical agitators into high-temperature fluidized beds. However, this introduces new and challenging problems: in the high-temperature activation environment of 800-950℃, the metal materials of the mechanical agitator (such as heat-resistant alloys) will inevitably wear down over long-term operation, and trace metal impurities will detach and contaminate the final product. This is a fatal flaw for applications requiring extremely high purity (such as battery electrode materials and high-end catalyst supports). Furthermore, mechanical agitation also presents a series of engineering challenges, including complex shaft seals, high equipment manufacturing costs, difficult maintenance, and reduced operational reliability.

[0043] On the other hand, from a reaction engineering perspective, existing steam activation processes are mostly carried out under atmospheric pressure. Under atmospheric pressure, the partial pressure of steam is low, and its gasification reaction rate with the carbon surface is limited by intrinsic chemical reaction kinetics, resulting in low activation efficiency. To achieve the ideal ablation rate and porosity development, it is often necessary to extend the activation time or increase the activation temperature. This not only increases energy consumption but may also lead to excessive ablation and reduced yield, especially as precise control of the mesoporous structure is difficult to achieve.

[0044] Therefore, there is an urgent need in this field to develop a new steam activation technology and equipment that can completely avoid metal contamination without relying on mechanical stirring, while significantly enhancing the mass and heat transfer process, and achieving a simultaneous improvement in activation reaction rate and selectivity, so as to meet the urgent demand of the high-end market for high-performance, high-purity porous carbon materials.

[0045] Specifically, please refer to Figure 1 The present invention provides a steam activation device 100 for porous carbon, including a reactor body 110, a steam inlet system 120, a carrier gas inlet system 130, a pressure control system 140 and an electric heating furnace 150. The structure and connection relationship of each part will be described in detail below.

[0046] (1) Reactor body 110.

[0047] The reactor body 110 consists of a reactor shell 111 and an inverted conical gas distributor 112 disposed at the bottom of the reactor shell 111. This invention facilitates gas distribution by providing the inverted conical gas distributor 112 at the bottom of the reactor shell 111.

[0048] The bottom of the reactor shell 111 is an inverted cone structure with a cone angle of 60°-150°. The inverted cone gas distributor 112 is installed to match the inverted cone structure. After the gas enters from the top of the cone, it diffuses outwards along the inner wall of the cone to avoid excessively high or low local gas concentrations. The diffusion angle of the cone is adapted to the cross-sectional size of the equipment, allowing the gas to cover the entire interior of the equipment without creating any "dead zones".

[0049] Uniformly distributed gas can fully contact the solid particles inside the equipment, improving reaction efficiency; the smooth transition structure of the inverted cone shape can reduce turbulence and impact during gas flow compared to flat plate or perforated plate distributors, thus reducing system energy consumption; the inclined angle of the cone-shaped inner wall can prevent solid particles or liquids from accumulating on the distributor surface, reducing the risk of blockage and ensuring long-term stable operation of the equipment.

[0050] There are various structures for the inverted conical gas distributor 112. Two typical but non-limiting examples are given in this invention:

[0051] The first type is an inverted conical gas distributor 112, which is an inverted conical metal sintered plate with an average pore size of 5-50 μm. In this scheme, the pore size of the inverted conical metal sintered plate is directly used to achieve uniform gas distribution.

[0052] The second type involves an inverted conical gas distributor 112 formed by the accumulation of chemically inert spherical particles at the bottom of the inverted conical reactor. The accumulation height is 1 / 3 to 2 / 3 of the cavity height, and the spherical particles are alumina or silica spheres with a diameter of 3-15 mm. In this design, uniform gas distribution is achieved by utilizing the gaps between the spherical particles.

[0053] Both of the above-mentioned inverted conical gas distributors 112 can achieve uniform gas distribution and diffusion, thereby improving process reaction / separation efficiency, reducing operating resistance, and reducing blockage.

[0054] In this invention, the bottom of the inverted conical gas distributor 112 is provided with a carrier gas inlet 113, and the upper middle part of the inverted conical gas distributor 112 is provided with a water vapor inlet 114. The top of the reactor shell 111 is provided with a feed port 115 and a gas outlet 116. Multiple thermocouples 117 for monitoring the reaction temperature are also provided inside the reactor shell 111. To avoid the exhaust gas discharged from the gas outlet 116 being mixed with materials, this invention also provides a metal filter column 118 at the top of the reactor shell 111. The exhaust gas is filtered by the metal filter column 118 before being discharged from the gas outlet 116.

[0055] (2) Water vapor intake system 120.

[0056] The steam intake system 120 includes a steam generating mechanism 121, an activation pipe 125, and an injection pipe 122. The steam generating mechanism 121 is connected to the injection pipe 122 through the activation pipe 125. The pulse branch 133 is connected to the part of the activation pipe 125 near the injection pipe 122 for periodically introducing pulse carrier gas into the activation pipe 125. The outlet of the injection pipe 122 is connected to the side wall of the reactor body 110.

[0057] In this invention, the injection pipe 122 is installed laterally and tilted downwards at 20-40°. This tilting prevents material from the bottom of the reactor body 110 from entering the injection pipe 122, thus avoiding blockage. The outlet end of the injection pipe 122 is designed as a nozzle structure, with its injection direction tilted downwards at an angle of 20°-45° to the horizontal plane, pointing towards the central area of ​​the reactor body 110.

[0058] In this invention, a quality control mechanism 123 is provided under the steam generating mechanism 121. The mechanism can determine the amount of steam generated by controlling the mass of the steam generating mechanism 121 before and after. The generated steam is pumped to the activation pipeline 125. A second preheating furnace 124 is provided on the activation pipeline 125, which can heat the steam before it is delivered to the injection pipe 122.

[0059] (3) Carrier air intake system 130.

[0060] The carrier gas inlet system 130 includes a carrier gas supply mechanism 131, an activation branch 137, a fluidization branch 132, and a pulse branch 133. The carrier gas supply mechanism 131 is connected to the activation branch 137, the fluidization branch 132, and the pulse branch 133 via a main pipe. The fluidization branch 132 is connected to the bottom of the reactor body 110 and is used to introduce fluidized carrier gas into the reactor body 110 to establish a sputtered fluidized bed. The steam generation mechanism 121 is connected to the activation branch 137, and the connection point is located before the second preheater 124, so that the second preheater 124 can heat the mixture of steam and activation carrier gas.

[0061] The pulse branch 133 is equipped with a pulse valve 134 and a timing controller (not shown) for controlling the opening and closing time of the pulse valve 134; the pulse frequency of the pulse valve 134 is 1-20 times per minute, and the pulse time is 0.1-5 seconds.

[0062] In this invention, a pulse valve 134 is used to pulse the carrier gas, forming a periodic pulsed gas. After mixing with water vapor, the gas enters the inverted conical gas distributor 112. The pulsed airflow disturbance technology replaces mechanical stirring, completely avoiding impurity contamination caused by wear of metal stirrers at high temperatures. The product purity is significantly improved, meeting the high-purity application requirements of electrode materials and other products.

[0063] The main pipe of the carrier gas supply mechanism 131 is also equipped with a first preheating furnace 138. The fluidization branch 132 and the pulse branch 133 are both connected to the first preheating furnace 138. The first preheating furnace 138 can heat the carrier gas separately, and then divide it into the fluidization branch 132 and the pulse branch 133, thereby ensuring that the carrier gas introduced into the reactor body 110 and the activation pipe 125 is heated, avoiding excessive temperature difference which is not conducive to the reaction.

[0064] In this invention, the second preheating furnace 124 preheats the mixture of activation carrier gas and water vapor. Preheating not only provides heat to the reactor body 110 but also prevents the introduction of unelectrified mixed gas, which could lower the bed temperature and cause a decrease or termination of the reaction rate. Furthermore, unelectrified mixed gas can cause abrupt changes in the density and viscosity of the gas within the bed, potentially disrupting the fluidization state of the particles. Preheating stabilizes the gas parameters, ensuring uniform particle suspension and sufficient gas-solid contact. Additionally, in this invention, a second flow meter 135 is installed on the activation branch 137, and a first flow meter 136 is installed on the fluidization branch 132. The use of these two flow meters allows for precise control of the flow rates of the activation and fluidization carrier gases on each branch.

[0065] A buffer tank 139 is also provided on the pulse branch 133. The buffer tank 139 is located between the first preheating furnace 138 and the pulse valve 134. The buffer tank 139 can reduce the flow variation of the pulse and make its pulse effect more stable.

[0066] It should be understood that the present invention independently sets up the activation pipeline 125 and the pulse branch 133, using the pulse branch 133 to independently supply pulsed gas to the activation pipeline 125. This setup ensures a stable input, stable pressurization, and stable proportion of water vapor when it enters the reactor body 110 from the activation pipeline 125. The independent pulse branch 133 is designed to introduce pulsed carrier gas in stages, using the external force of the pulse to disturb the agglomerated particles during fluidization, thereby improving the fluidization effect. If the pulse valve is directly set on the activation pipeline 125, and the mixture of water vapor and activation carrier gas is used for activation and pulsed reactions simultaneously, this would cause intermittent water vapor flow into the reactor body 110, leading to interruptions in the reaction process. Since water vapor participates in the reaction, the entire reaction process is achieved through gas diffusion and reaction. If water vapor is introduced periodically as a pulsed gas, it would affect the overall reaction time, reaction efficiency, and final etching efficiency.

[0067] In addition, this application also needs to limit the amount of water vapor and activation carrier gas, with a ratio of 1:8 to 8:1. If there is too much water vapor, the reaction will be too violent, resulting in excessive etching and an excessively high burn rate. By limiting the ratio of water vapor to activation carrier gas, this application can achieve a stable and appropriate input of water vapor, avoiding the adverse effects caused by fluctuations in the amount of water vapor.

[0068] (4) Pressure control system 140.

[0069] In this invention, the pressure control system 140 is connected to the reactor body 110 to control the pressure inside the reactor body 110. By controlling the pressure inside the reactor body 110 through the pressure control system 140, the partial pressure of water vapor and the reaction rate are significantly improved through pressurization (0.1-0.5MPa), and the activation efficiency is increased by more than 30% compared with the atmospheric pressure process, effectively reducing energy consumption and reaction time.

[0070] In this invention, the pressure control system 140 includes a back pressure valve 141 and a pressure gauge 142. The back pressure valve 141 is connected to the gas outlet pipe at the top of the reactor shell 111, and the pressure gauge 142 is connected to the top of the reactor shell 111. The pressure is directly regulated using the back pressure valve 141 on the gas outlet pipe, which is convenient and provides precise pressure control.

[0071] (5) Electric heating furnace 150.

[0072] The electric heating furnace 150 is used to heat the reactor body 110. Specifically, the electric heating furnace 150 is sleeved on the outside of the reactor shell 111 of the reactor body 110. The electric heating furnace 150 can be used to regulate the temperature inside the reactor body 110 so that the reaction can be carried out at a suitable reaction temperature.

[0073] Furthermore, the present invention also provides a steam activation method for porous carbon, which uses the aforementioned steam activation device 100 for porous carbon and includes the following steps:

[0074] S1: The carbon material is loaded into the reactor body 110 and sealed. Nitrogen gas is then introduced into the reactor body 110 through the fluidization branch 132 of the carrier gas inlet system 130 to establish a sputtered fluidized bed.

[0075] In this invention, the carbon material is a carbon precursor with a particle size of 1-10 mm; preferably, the carbon precursor is any one of coconut shell carbon, coal-based carbon, and resin carbon.

[0076] The carrier gas introduced into the carrier gas inlet system 130 is nitrogen gas, and the gas velocity is controlled to be 3 to 20 times the minimum fluidizing gas velocity Umf. By continuously introducing the carrier gas, the carrier gas can suspend the solid carbon material particles in the reactor body 110 and form a "fluidized state".

[0077] S2: Start the electric heating furnace 150 to heat the reactor body 110 to 800-950℃, and adjust the pressure control system 140 to maintain the absolute pressure inside the reactor body 110 at 0.1~0.5MPa.

[0078] S3: Water vapor is introduced through the water vapor inlet system 120 at a rate of 0.5~5 g water vapor / 1g carbon·h. At the same time, the pulse branch 133 is activated to periodically pulse carrier gas into the activation pipeline 125. The pressure of the pulsed carrier gas is 0.1-0.3 MPa higher than the operating pressure in the reactor body 110, which disturbs and enhances the mixing of the spouting fluidized bed. Under these conditions, the activation reaction is carried out for 1~5 hours.

[0079] In this invention, by controlling the carrier gas pressure introduced by the pulse to be 0.1-0.3 MPa higher than the operating pressure inside the reactor body 110, it is possible to effectively impact any potential blockages in the water spray pipe and prevent them from becoming blocked.

[0080] S4: After the reaction is complete, stop the steam supply, cool under a carrier gas atmosphere, and remove the porous carbon product.

[0081] Porous carbon products with a specific surface area ≥1800 m² 2 / g, total pore volume is 0.8~1.5 cm³ 3 / g, and the mesopore ratio is ≥40%.

[0082] The present invention will be further described below with reference to specific embodiments.

[0083] Example 1

[0084] This embodiment uses the device of the present invention for porous carbon steam activation. The device configuration includes: a reactor body 110 made of 310S stainless steel, with a 90° inverted conical bottom structure and equipped with a 20μm pore size metal sintered plate gas distributor; an injection pipe 122 installed laterally and inclined downward at 30°; a pulse branch 133 equipped with an electromagnetic pulse valve 134; a pressure control system 140 using a back pressure valve 141; and a heating system using a three-stage electric heating furnace 150.

[0085] 20 kg of coconut shell charcoal with a particle size of 2-5 mm was loaded into the reactor body 110. After sealing, nitrogen gas was introduced at 10 times the minimum fluidizing gas velocity Umf, where the minimum fluidizing gas velocity Umf is 0.0097 m / s. The temperature was raised to 920℃, and the back pressure valve 141 was adjusted to stabilize the absolute pressure of the system at 0.3 MPa. Water vapor (flow rate 2.5 g / g charcoal·h) and activation carrier gas were introduced into the activation pipeline 125 using the steam generation mechanism 121 and the activation branch 137 of the carrier gas inlet system 130. The volumetric flow rate ratio of water vapor to activation carrier gas in the activation pipeline 125 was 1:8. At the same time, the pulse valve 134 on the pulse branch 133 was activated (frequency 10 times / minute, duration 0.5 seconds, pulse pressure 0.2 MPa higher than the reaction pressure). Activation was stopped after 5 hours, resulting in a BET specific surface area of ​​2150 m². 2 / g, porous carbon product with a mesopore ratio of 52%, uniform temperature distribution inside the reactor, axial temperature difference <15℃.

[0086] Example 2

[0087] The device configuration in this embodiment is based on that in embodiment 1, but uses α-alumina balls with a diameter of 6-8 mm to form a distribution layer with a stacking height of 150 mm; the spray pipe 122 is installed horizontally and uses a multi-hole nozzle; and a buffer tank 139 is added to the pulse branch 133.

[0088] 20 kg of coal-based char was loaded into the reactor body 110 and sealed. Nitrogen gas was introduced at 20 times the minimum fluidizing gas velocity Umf (0.0105 m / s). The temperature was raised to 880℃, and the back pressure valve 141 was adjusted to stabilize the system absolute pressure at 0.4 MPa. Water vapor (flow rate 2.5 g / g char·h) and activation carrier gas were introduced into the activation pipeline 125 via the steam generation mechanism 121 and the activation branch 137 of the carrier gas inlet system 130. The volumetric flow rate ratio of water vapor to activation carrier gas in the activation pipeline 125 was 1:4. Simultaneously, the pulse valve 134 on the pulse branch 133 was activated (frequency 15 times / minute, duration 0.5 seconds, pulse pressure 0.2 MPa higher than the reaction pressure). Activation was stopped after 3 hours, yielding a BET specific surface area of ​​1980 m². 2 Porous carbon products with a porosity of 48% and a mesopore ratio have a uniform temperature distribution within the reactor, with an axial temperature difference of <15℃ and a more uniform bed temperature.

[0089] Example 3

[0090] This embodiment is basically the same as Embodiment 1, except that it uses a narrow conical reactor bottom structure with a cone angle of 60°, and a 10μm aperture metal sintered plate gas distributor as an inverted conical gas distributor 112. A pneumatic piston-type pulse valve 134 is used to provide stronger impact force. The back pressure valve 141 is adjusted to stabilize the system absolute pressure at 0.2MPa for activation, the pulse duration is extended to 1.0 second, and the activation temperature is increased to 950℃. The enhanced pulse effectively improves the material mixing effect, and the product's BET specific surface area reaches 2380m². 2 / g, mesopore ratio 55%.

[0091] Example 4

[0092] This embodiment examines the effects of different pulse conditions. The apparatus is the same as in Example 1, with other conditions fixed, but the pulse frequency is changed to 5 pulses / minute. It was found that while clogging was still prevented, the bed mixing effect decreased, and the product specific surface area decreased by approximately 8% compared to Example 1. This demonstrates that a pulse frequency of 10 pulses / minute is the optimal choice for achieving the best mixing effect.

[0093] Example 5

[0094] This embodiment examines the influence of different distributor materials. Fused silica spheres were used instead of α-alumina spheres as the distribution layer material, with the same stacking method and height as in Example 2. Under the same process conditions, due to the lower heat capacity of the silica spheres, the steam preheating effect was slightly worse, but a good distribution effect was still maintained, and the product performance was comparable to that of Example 2, indicating that different inert materials can achieve the purpose of this invention.

[0095] Comparative Example 1 (Ambient Pressure Operation)

[0096] This comparative example uses the same apparatus as Example 1, but without the back pressure valve 141, and activation is performed at atmospheric pressure. The activation time needs to be extended to 4 hours to achieve a comparable level of activation, increasing energy consumption by 50%, demonstrating the important role of pressurized operation in improving the reaction rate.

[0097] Comparative Example 2 (No Pulse)

[0098] This comparative example is basically the same as Example 1, except that pulse valve 134 is closed in this comparative example, and only water vapor (flow rate 2.5 g / g carbon·h) and activation carrier gas are continuously introduced. The volumetric flow rate ratio of water vapor to activation carrier gas in activation pipeline 125 is 1:8. After 1.5 hours of reaction, the water vapor flow rate decreased significantly, and the outlet of the injection pipe was found to be partially blocked, resulting in poor product uniformity and a 15% difference in specific surface area between samples taken from different locations.

[0099] Comparative Example 3 (Mechanical Stirring Device)

[0100] This comparative example is basically the same as Example 1, except that a mechanical stirring device (alloy stirring paddle) is installed on the top of the reactor shell 111, and the pulse branch 133 is removed. The presence of metallic impurities (ash content 2.5%) in the product and leakage at the stirring shaft seal demonstrate that mechanical stirring inevitably leads to pollution and reliability issues under high-temperature conditions.

[0101] Comparative Example 4 (Ambient pressure operation and no pulse)

[0102] This comparative example uses the same apparatus as Example 1, but without the back pressure valve 141. Activation is performed at atmospheric pressure, and the pulse valve 134 is closed, with only water vapor (flow rate 2.5 g / g char·h) and activation carrier gas continuously introduced. The volumetric flow rate ratio of water vapor to activation carrier gas in activation pipeline 125 is 1:8. After 1.5 hours of reaction, the water vapor flow rate significantly decreased, and detection revealed partial blockage at the nozzle outlet. Product uniformity deteriorated, with a 28% difference in specific surface area between samples taken from different locations (1430-1850 m²). 2 / g, with a low value below 1800m 2 / g). The activation time needs to be extended to 7 hours to achieve a considerable degree of activation, and the energy consumption increases by 60%, which proves the important role of pressurized operation in improving the reaction rate.

[0103] Comparative Example 5

[0104] This comparative example uses the same apparatus as Example 1, but the pulse pressure in pulse branch 133 is the same as the reaction pressure. During the reaction, the pulse branch disturbance function fails, resulting in localized fluidization of the jet-fluidized bed with an axial temperature difference reaching 42°C. After 2.5 hours of activation, the product has a specific surface area of ​​1680 m². 2 / g (less than 1800m) 2 / g), with a mesopore ratio of 38% (below 40%), uneven particle pore size, and a tendency to clog in the inverted conical metal sintered plate.

[0105] Comparative Example 6

[0106] This comparative example uses the same apparatus as Example 1, but the ratio of water vapor to activation carrier gas introduced into activation pipeline 125 is 10:1. In this case, the water vapor flow rate is too high, resulting in a product with a specific surface area of ​​1200-1300 m² after 4 hours of activation. 2 / g (less than 1800m) 2 / g), with a mesopore ratio of 35% (less than 40%), the particle pore size is uneven, and some mesopores and micropores in the porous carbon collapse, resulting in a decrease in the overall pore volume. Through particle size analysis, the proportion of particles with a diameter less than 2μm in this comparative example increased compared to Example 1, indicating that the high water vapor concentration caused the activation reaction to be too fast and had a reduction effect on the particle size of some small particles.

[0107] In summary, the porous carbon steam activation device 100 and method provided by the present invention form a fluidized bed in the reactor body 110 through the fluidization branch 132 of the carrier gas inlet system 130, pressurize the reaction pressure in the reactor body 110 using the pressure control system 140, and facilitate the introduction of pulsed steam into the reactor body 110 by cooperating with the steam inlet system 120 and the pulse branch 133 of the carrier gas inlet system 130. In this invention, pressurization significantly improves the partial pressure of water vapor and the reaction rate, increasing the activation efficiency by more than 30% compared to atmospheric pressure processes, effectively reducing energy consumption and reaction time. Pulsed airflow disturbance technology replaces mechanical stirring, completely avoiding impurity contamination caused by metal stirrer wear at high temperatures, significantly improving product purity and meeting the high-purity application requirements of electrode materials, etc. Combined with directional pulsed airflow, it achieves thorough and uniform mixing of materials within the reactor, solving the dead zone and channeling problems present in traditional fluidized beds. The device has a simple structure, high reliability, and low maintenance costs, avoiding engineering challenges such as high-temperature dynamic sealing, making it easier for industrial scale-up and production. The prepared porous carbon product has a high specific surface area and a well-developed mesoporous structure, with a specific surface area ≥1800 m². 2 With a porosity of ≥45%, it exhibits excellent electrochemical performance in applications such as supercapacitors.

[0108] The results of the above embodiments demonstrate that the device of the present invention, through its unique structural design and the coordination of the pulse branch 133, achieves a highly efficient and stable steam activation process, effectively solving the problems of clogging, contamination, and uneven mixing found in traditional devices. Multiple embodiments prove the applicability and superiority of the present invention under different process parameters and configurations.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A steam activation device for porous carbon, characterized in that, It includes the reactor body, steam inlet system, carrier gas inlet system, pressure control system and electric heating furnace; The carrier gas inlet system includes a carrier gas supply mechanism, a fluidization branch, and a pulse branch. The fluidization branch and the pulse branch are respectively connected to the carrier gas supply mechanism. The fluidization branch is connected to the bottom of the reactor body and is used to introduce fluidized carrier gas into the reactor body to establish a jet fluidized bed. The steam intake system includes a steam generating mechanism, an activation pipeline, and an injection pipe. The steam generating mechanism is connected to the injection pipe through the activation pipeline. The pulse branch is connected to the activation pipeline for periodically introducing pulsed carrier gas into the activation pipeline. The outlet of the injection pipe is connected to the side wall of the reactor body. The pressure control system is connected to the reactor body to control the pressure inside the reactor body; the electric heating furnace is fitted onto the outside of the reactor body.

2. The steam activation device for porous carbon according to claim 1, characterized in that, The pulse branch is equipped with a pulse valve and a timer controller for controlling the opening and closing time of the pulse valve; the pulse frequency of the pulse valve is 1-20 times per minute, and the pulse time is 0.1-5 seconds. And / or, the carrier gas intake system further includes a first preheating furnace, and the fluidization branch and the pulse branch are both connected to the first preheating furnace; And / or, a buffer tank is also provided on the pulse branch, the buffer tank being located between the first preheating furnace and the pulse valve; And / or, a first flow meter is provided on the fluidization branch.

3. The steam activation device for porous carbon according to claim 1, characterized in that, The carrier gas intake system also includes an activation branch, the carrier gas supply mechanism is connected to the activation branch, the activation branch is connected to the activation pipeline, and a second preheating furnace for heating the activation carrier gas and water vapor is provided on the activation pipeline.

4. The steam activation device for porous carbon according to claim 1, characterized in that, The reactor body consists of a reactor shell and an inverted conical gas distributor located at the bottom of the reactor shell, and the electric heating furnace is fitted on the outside of the reactor shell.

5. The steam activation device for porous carbon according to claim 4, characterized in that, The bottom of the reactor shell is an inverted cone structure with a cone angle of 60°-150°; the inverted cone gas distributor is installed in a way that matches the inverted cone structure.

6. The steam activation device for porous carbon according to claim 5, characterized in that, The inverted conical gas distributor is an inverted conical metal sintered plate with an average pore size of 5-50 μm; Alternatively, the inverted conical gas distributor is formed by the accumulation of chemically inert spherical particles at the bottom of the inverted conical reactor, wherein the spherical particles are alumina or silica spheres with a diameter of 3-15 mm.

7. The steam activation device for porous carbon according to claim 4, characterized in that, The pressure control system includes a back pressure valve and a pressure gauge. The back pressure valve is connected to the gas outlet pipe at the top of the reactor shell, and the pressure gauge is connected to the top of the reactor shell.

8. A method for steam activation of porous carbon using the apparatus described in any one of claims 1-7, characterized in that, Includes the following steps: S1: The carbon material is loaded into the reactor body and sealed. Then, the fluidized carrier gas is introduced into the reactor body through the fluidized branch of the carrier gas inlet system to establish a jet fluidized bed. S2: Start the electric heating furnace to heat the reactor body to 800-950℃, and adjust the pressure control system to maintain the absolute pressure inside the reactor body at 0.1~0.5MPa; S3: Water vapor and activation carrier gas are introduced into the activation pipeline through the activation branch of the water vapor inlet system and the carrier gas inlet system. At the same time, the pulse branch is activated to periodically introduce pulse carrier gas into the activation pipeline to disturb and enhance the mixing of the jet fluidized bed. Under these conditions, the activation reaction is carried out for 1 to 5 hours. S4: After the reaction is complete, stop the flow of steam and activation carrier gas, cool under the atmosphere of fluidized carrier gas, and take out the porous carbon product.

9. The steam activation method for porous carbon according to claim 8, characterized in that, The steam flow rate is 0.5~5 g steam / 1g carbon·h; And / or, the volumetric flow rate ratio of the water vapor and the activation carrier gas in the activation pipeline is 1:8-8:1; And / or, the pulse carrier gas pressure introduced into the pulse branch is 0.1-0.3 MPa higher than the operating pressure inside the reactor body; And / or, the carrier gas introduced into the carrier gas intake system is nitrogen, and the gas velocity is controlled to be 3 to 20 times the minimum fluidizing gas velocity Umf.

10. The steam activation method for porous carbon according to claim 8, characterized in that, The carbon material is a carbon precursor with a particle size of 1-10 mm; the carbon precursor includes any one of coconut shell carbon, coal-based carbon, and resin carbon. and / or, the specific surface area of the porous carbon product is ≥ 1800 m 2 / g, and the total pore volume is 0.8~1.5 cm 3 / g, and the mesopore ratio is ≥ 40%.

Images