Porous carbon activation system for circulating heat-carrying particles

Abstract

The invention relates to the technical field of porous carbon activation, in particular to a porous carbon activation system for heat-carrying particle circulation, which comprises: a fluidized bed reaction unit; a cooling and discharging unit; a feeding unit; the tail gas conveying unit is used for collecting reaction tail gas formed after the activation reaction; the activated gas supply unit is used for conducting heat of the reaction tail gas to the activated gas for preheating and mixing the reaction tail gas with the activated gas to output mixed activated gas; the heat-carrying particle heating unit is used for heating the heat-carrying particles which do not enter; the conveying and separating unit is used for conveying the heated heat-carrying particles to an activation reaction area in the fluidized bed reaction unit so as to provide heat required by an activation reaction, and comprises a lifting pipe, a cyclone separator and a conveying fan which are used for supplying conveying pressure to the heat-carrying particles and reaction raw materials by introducing nitrogen into the fluidized bed reaction unit. According to the invention, the specific surface area and the microporosity of the porous carbon are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous carbon activation, and particularly relates to a porous carbon activation system with heat-carrying particle circulation. BACKGROUND

[0002] In the prior art, as the core power carrier of new energy technology, the breakthrough of energy density and cycle life of lithium ion batteries highly depends on the innovation of negative electrode materials. Silicon-based negative electrode materials are considered as the key to the next generation of high-energy batteries due to their ten times theoretical capacity of graphite. However, the high volume expansion of up to 300% during the charging and discharging process leads to structural pulverization failure, which seriously restricts the practical process. By uniformly loading nano-silicon in the porous carbon matrix to construct a composite negative electrode material, the expansion stress can be effectively dispersed and the electrode integrity can be maintained. The industrialization of this technical path urgently needs a porous carbon host material with high specific surface area, gradient pore size and excellent structural stability. However, the inherent defects exposed by the existing porous carbon preparation equipment in industrialization have become a key bottleneck restricting the performance improvement and cost reduction of silicon-carbon negative electrodes. As the core equipment for large-scale production of porous carbon, the performance of the fluidized bed reactor directly determines the material quality and production cost. Due to the structural design limitations of the current mainstream equipment, it is difficult to balance the uniformity of the temperature field, fluidization efficiency and energy consumption control. For ultra-fine carbon powder with a particle size less than 10 μm, its strong agglomeration tendency leads to the formation of local high temperature zones (temperature difference exceeds ± 80℃) in the bed layer. The microporous structure is excessively ablated at high temperature, while the edge area is insufficiently activated due to the lag of heat conduction, and the specific surface area of the product fluctuates by ± 250 m² / g, and the pore size distribution is more than 30%. At the same time, the traditional fluidized bed relies on the static heat conduction mode of the external heating module, and the heat recovery rate of the exhaust gas with a temperature higher than 800℃ is less than 20%. The heat-carrying medium is discarded after a single use, causing additional energy consumption. Combined with the strong endothermic characteristics of the activation reaction, the comprehensive energy consumption is more than 3 times higher than the theoretical value. More seriously, the rough gas distribution design leads to a high entrainment rate of ultra-fine particles, and the continuous operation cycle of the equipment is short, and frequent maintenance further increases the production cost. The existing technology improves the multi-focus local optimization, but fails to break through the systematic defects of the equipment. For example, the zoned electric heating scheme can reduce the axial temperature difference, but it does not solve the problem of radial temperature gradient. The improvement of the gas pre-distributor improves the uniformity of fluidization, but it causes the pressure drop to multiply and the energy consumption to rise. The traditional cyclone separation system is prone to blockage and failure under high temperature working conditions, and cannot realize efficient separation of the heat-carrying medium and the product. Under this background, developing a new equipment system integrating dynamic regulation of the thermal field, optimization of the fluidization state and energy closed-loop management has become a key breakthrough to solve the problem of industrial production of porous carbon.

[0003] Chinese Patent Publication No. CN119240698A discloses a system and method for preparing porous electrode carbon, comprising a carbonization fluidized bed, an activation fluidized bed, and a heat carrier removal reactor connected in series. A porous distribution plate is provided within the reaction zone of the carbonization fluidized bed, dividing the reaction zone into a first reaction zone and a second reaction zone. The first reaction zone has a fluidizing gas inlet and a composite carbonization material outlet, while the second reaction zone has a mixed raw material inlet and a fluidization tail gas outlet. An overflow pipe is provided outside the carbonization fluidized bed, with one end connected to the first reaction zone and the other end connected to the second reaction zone. An activation gas inlet and an activation material outlet are provided at the bottom of the activation fluidized bed. A composite carbonization material inlet and an activation tail gas outlet are provided above the activation fluidized bed. The heat carrier removal reactor contains acid or water. Therefore, the porous electrode carbon preparation system and method have problems such as small specific surface area and low microporosity of porous carbon due to the uneven temperature field, unstable fluidization of ultrafine particles, excessive energy consumption and short continuous operation cycle of existing fluidized bed activation equipment during the preparation of porous carbon. Summary of the Invention

[0004] Therefore, the present invention provides a porous carbon activation system with heat-carrying particle circulation to overcome the problems of small specific surface area and low microporosity of porous carbon caused by the uneven temperature field, unstable fluidization of ultrafine particles, excessive energy consumption and short continuous operation cycle of existing fluidized bed activation equipment in the process of preparing porous carbon.

[0005] To achieve the above objectives, the present invention provides a porous carbon activation system with circulating heat-carrying particles, comprising: Fluidized bed reaction unit is used to activate the reactants through activating gas and heat-carrying particles to convert them into porous carbon; A cooling and unloading unit, which is connected to the fluidized bed reaction unit, is used to cool the output porous carbon. A feeding unit, which is located above the cooling and unloading unit, is used to transport the reaction raw materials, including a raw material tank for loading the reaction raw materials and a discharge valve connected to the raw material tank for controlling whether the raw materials are transported. The exhaust gas conveying unit is connected to the fluidized bed reaction unit and is used to collect the reaction exhaust gas formed after the activation reaction. An activation gas supply unit, which is connected to the tail gas delivery unit, is used to transfer the heat of the reaction tail gas to the activation gas for preheating and mixing with the activation gas to output a mixed activation gas. a conveying and separating unit connected to the fluidized bed reaction unit, for conveying the heated heat-carrying particles to an activation reaction area in the fluidized bed reaction unit to provide heat required for the activation reaction, comprising a riser vertically arranged outside the raw material tank and providing conveying pressure for the heat-carrying particles by supplying nitrogen into the fluidized bed reaction unit, a cyclone separator connected to the riser for separating the heat-carrying particles from the porous carbon, and a conveying fan connected to the cyclone separator for providing conveying power for the separated heat-carrying particles; a heat-carrying particle heating unit connected to the conveying and separating unit, for heating the heat-carrying particles not entering the fluidized bed reaction unit, comprising a heating buffer tank connected to the riser for reducing the gas pressure of the input nitrogen and heating the heat-carrying particles, and a heating furnace connected to the heating buffer tank for heating the heating buffer tank.

[0006] Further, the heat-carrying particles at least include one of alumina, silica, zirconia, and silicon carbide.

[0007] Further, the fluidized bed reaction unit comprises: a reaction tank for providing a reaction site for the activation reaction; a particle pre-distributor arranged inside the reaction tank for reducing the entering speed of the heat-carrying particles; a gradient gas distributor arranged at the top of the reaction tank for forming a gradient gas flow of the activation gas to mix the reaction raw material and the heat-carrying particles; a metal filter arranged below the gradient gas distributor for filtering the carbon powder in the reaction tail gas.

[0008] Further, the discharging mode of the cooling and discharging unit is a pressurized pneumatic conveying discharging mode.

[0009] Further, the activation gas supply unit comprises: a gas mixing tank for mixing the reaction tail gas and the activation gas to form a mixed activation gas; a plurality of flow meters connected to the gas mixing tank for respectively detecting the flow rates of the activation gas, the reaction tail gas, and the mixed activation gas; a gas preheating furnace connected to the gas mixing tank for heating the mixed activation gas.

[0010] Further, the tail gas conveying unit comprises: a tail gas conveying pipeline connected to the gas mixing tank; a circulating fan connected to the tail gas conveying pipeline for conveying the reaction tail gas to the gas mixing tank.

[0011] Further, the volume ratio of the reaction tail gas and the activation gas in the gas mixing tank is 3:7-5:5.

[0012] Further, the gas species of the activation gas includes water vapor and carbon dioxide.

[0013] Further, the fluidized bed reaction unit further comprises a conveying port assembly, and the conveying port assembly is provided with a reaction tail gas outlet, a heat carrier particle inlet, a heat carrier particle outlet and a gas inlet from top to bottom.

[0014] Further, the heat carrier particle inlet is provided with a high-temperature valve for adjusting the flow of the heat carrier particles.

[0015] Compared with the prior art, the system has the beneficial effects that the system comprises a fluidized bed reaction unit, a cooling and discharging unit, a feeding unit, a tail gas conveying unit, an activation gas supply unit, a heat carrier particle heating unit and a conveying and separating unit. In the traditional fluidized bed activation equipment, the heat transfer mode is single, which leads to uneven temperature distribution in the activation reaction area, affects the development of the microstructure of the porous carbon, and causes non-ideal fluidization phenomena such as channeling and surging of the micron or nanometer raw material particles, thereby reducing the reaction efficiency. In the traditional process, the heat energy utilization rate is low, the heating process consumes a large amount of energy, and energy is wasted. Due to unreasonable equipment design or poor running stability, the system frequently stops for maintenance, thereby reducing the production efficiency. The above factors jointly cause the specific surface area of the finally produced porous carbon to be small and the micropore rate to be low. The heat carrier particles are circulated by the heat carrier particle circulation unit, heat transfer is replaced by static wall heating, the uniform development of the microporous structure of the porous carbon is ensured, and the specific surface area fluctuation is reduced. The high-temperature tail gas is conveyed to the gas mixing tank by the tail gas conveying unit in the porous carbon treatment unit, mixed with fresh activation gas, heated by a preheating furnace, and the sensible heat of the tail gas is directly recovered, thereby improving the waste heat utilization rate. The energy consumption of the preheated gas is reduced by heat energy recovery, the situation of destroying fluidization caused by cold material into the bed is reduced, the specific surface area and micropore rate of the produced porous carbon are improved, the uniformity and performance stability of the product are improved, the heat utilization mechanism is reconstructed, the porous carbon activation and heat carrier particle separation process are optimized, and an energy closed-loop network is constructed by tail gas circulation, thereby realizing efficient, stable and low-consumption continuous production of the porous carbon material.

[0016] Further, the system of the present application preheats the heat-carrying particles to a high temperature range required for the activation reaction before the heat-carrying particles participate in the activation reaction, and the preheated heat-carrying particles are sent to the fluidized bed reaction unit by nitrogen as the conveying medium, and the gas flow speed is reduced by the heating buffer tank in the process to prevent the heat-carrying particles from being broken due to high-speed collision, and then the heat-carrying particles are uniformly dispersed into a fine and dense beam flow into the activation reaction area by the particle pre-distributor, so as to ensure sufficient contact and heat transfer with the reaction raw materials, and then improve the temperature distribution uniformity of the reaction area, and avoid the problems of excessive ablation of micropores caused by local high temperature or insufficient activation in low temperature area; the preheated heat-carrying particles provide a continuous and stable heat source for the activation reaction, and improve the uniformity of the microporous structure of the porous carbon.

[0017] Further, the system of the present application introduces high-temperature alumina, silicon dioxide and metal particles into the fluidized bed reaction unit by the heat-carrying particle circulation unit, and significantly improves the temperature uniformity of the activation reaction area by using the high heat capacity and good heat transfer performance, so as to improve the specific surface area and microporosity of the porous carbon, and the recycling of the heat-carrying particles not only improves the heat energy utilization rate and reduces the overall energy consumption, but also enhances the continuous operation capacity of the system and prolongs the operation cycle.

[0018] Further, the system of the present application realizes the gradient distribution of the activation gas in the fluidized bed by setting the particle pre-distributor, the gradient gas distributor and the metal filter, improves the gas-solid contact efficiency; by setting the circulating fan and the tail gas conveying pipeline, the incomplete reaction components in the reaction tail gas are recycled to participate in the reaction again, which not only improves the utilization rate of raw materials, but also reduces the environmental pollution caused by the emission of reaction tail gas, and further heats the tail gas waste heat to reduce energy consumption and increase the temperature uniformity of the mixed gas.

[0019] Further, the system of the present application adopts the pressure pneumatic conveying mode to avoid the blockage and wear caused by the traditional mechanical conveying, and improves the continuity and stability of the feeding and discharging process, and the setting of the metal filter reduces the escape of fine particles with the tail gas and improves the stability of the normal operation of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a schematic diagram of a porous carbon activation system with heat-carrying particle circulation according to an embodiment of the present application; Figure 2 FIG. 2 is a flowchart of an activation reaction of a porous carbon activation system with heat-carrying particle circulation according to an embodiment of the present application; Figure 3 FIG. 3 is a schematic diagram of a fluidized bed reaction unit of a porous carbon activation system with heat-carrying particle circulation according to an embodiment of the present application; 1 - heated surge tank, 2 - raw material tank, 3 - riser, 4 - discharge valve, 5 - reaction tank, 6 - loop, 7 - gradient gas distributor, 8 - discharge valve, 9 - collection tank, 10 - circulating fan, 11 - flow meter, 12 - gas preheating furnace, 13 - nitrogen pulse backflushing filter column, 14 - particle pre-distributor, 15 - reaction tail gas outlet, 16 - heat carrier particle inlet, 17 - gas inlet, 18 - heat carrier particle outlet, 19 - cyclone separator, 20 - tail gas conveying pipeline, 21 - gas mixing tank. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present application clearer, the present application will be further described in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0022] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that the embodiments are only used to explain the technical principles of the present application and are not used to limit the protection scope of the present application.

[0023] It should be noted that, in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0024] In addition, it should also be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0025] Please refer to Figure 1 , Figure 2 , Figure 3 The present application is a heat carrier particle circulating porous carbon activation system, including: A fluidized bed reaction unit is used to perform an activation reaction on the reaction raw material by the activation gas and the heat carrier particles to convert into porous carbon; a cooling and discharging unit connected to the fluidized bed reaction unit to cool the output porous carbon; a feeding unit disposed above the cooling and discharging unit to feed the reaction raw material, including a raw material tank to load the reaction raw material and a discharge valve connected to the raw material tank to control whether to feed the raw material; an exhaust gas feeding unit connected to the fluidized bed reaction unit to collect reaction exhaust gas formed after the activation reaction; an activation gas supply unit connected to the exhaust gas feeding unit to conduct heat of the reaction exhaust gas to the activation gas to preheat and mix the activation gas to output mixed activation gas; a feeding and separating unit connected to the fluidized bed reaction unit to feed the heated heat-carrying particles to the activation reaction area in the fluidized bed reaction unit to provide heat required for the activation reaction, including a riser vertically disposed outside the raw material tank to provide a feeding pressure for the heat-carrying particles by supplying nitrogen gas into the fluidized bed reaction unit, a cyclone separator connected to the riser to separate the heat-carrying particles from the porous carbon, and a feeding blower connected to the cyclone separator to provide a feeding power for the separated heat-carrying particles; a heat-carrying particle heating unit connected to the feeding and separating unit to heat the heat-carrying particles not entering the fluidized bed reaction unit, including a heating buffer tank connected to the riser to reduce the gas pressure of the input nitrogen gas and heat the heat-carrying particles, and a heating furnace connected to the heating buffer tank to heat the heating buffer tank.

[0026] Specifically, the cooling and discharging unit includes: a discharging valve 8 connected to the reaction tank 5 to control whether to output the porous carbon from the reaction tank 5; a receiving tank 9 connected to the discharging valve 8 to collect the porous carbon; a heat exchange pipe disposed on the tank wall of the receiving tank 9 to cool the receiving tank 9; a condenser connected to the heat exchange pipe, wherein the heat exchange pipe can also be replaced by a water-cooled wall.

[0027] In the implementation, the system described in the application sets a fluidized bed reaction unit, a cooling and unloading unit, a feeding unit, a tail gas conveying unit, an activation gas supply unit, a heat-carrying particle heating unit, and a conveying and separating unit. Due to the single heat transfer mode of the traditional fluidized bed activation equipment, the temperature distribution of the activation reaction area is uneven, which affects the microstructure development of the porous carbon, and the micron or nanometer raw material particles are prone to non-ideal fluidization phenomena such as channeling and surging, which leads to a decrease in reaction efficiency. In the traditional process, the heat energy utilization rate is low, the heating process consumes a lot of energy, and energy is wasted. Due to unreasonable equipment design or poor running stability, the system frequently stops for maintenance, which further leads to a decrease in production efficiency. The above factors together lead to a small specific surface area and low micropore rate of the final produced porous carbon. The heat-carrying particles are circulated through the heat-carrying particle circulation unit, the static wall heating is replaced by heat transfer, the uniform development of the microporous structure of the porous carbon is ensured, and the specific surface area fluctuation is reduced. The high-temperature tail gas is conveyed to the gas mixing tank through the tail gas conveying unit in the porous carbon treatment unit, mixed with fresh activation gas, heated by the preheating furnace, and the sensible heat of the tail gas is directly recovered, thereby improving the waste heat utilization rate. Through heat energy recovery, the energy consumption of the preheated gas is reduced, the situation of destroying fluidization caused by cold material into the bed is reduced, and the specific surface area and micropore rate of the produced porous carbon are improved. The product uniformity and performance stability are improved. By reconstructing the heat utilization mechanism, optimizing the porous carbon activation and heat-carrying particle separation process, and constructing an energy closed-loop network through tail gas circulation, the efficient, stable, and low-consumption continuous production of porous carbon materials is realized.

[0028] Specifically, the heat-carrying particles at least include one of aluminum oxide, silicon dioxide, zirconium oxide, and silicon carbide.

[0029] Specifically, the particle size of the heat-carrying particles is not more than 300 μm, and the preferred particle size range is 80-120 μm. The preferred shape of the heat-carrying particles is spherical particles.

[0030] Specifically, the heat-carrying particle heating unit includes a heating buffer tank and a heating furnace. The heating buffer tank adopts any one of a fluidized bed, a moving bed, a rotary furnace, and a fixed bed, and the preferred embodiment of the heating buffer tank is a fluidized bed. The heating mode of the heating furnace adopts any one of resistance heating, electromagnetic induction heating, and natural gas combustion heating.

[0031] In the implementation, the system of the present application preheats the heat-carrying particles to a high temperature range required for the activation reaction before the heat-carrying particles participate in the activation reaction, and the preheated heat-carrying particles are sent to the fluidized bed reaction unit by nitrogen as the conveying medium through the riser, the gas flow speed is reduced by the heating buffer tank in the way to prevent the heat-carrying particles from being broken due to high-speed collision, and the heat-carrying particles are uniformly dispersed into fine and dense streams into the activation reaction area by the particle pre-distributor, so as to ensure sufficient contact and heat transfer with the reaction raw materials, and further improve the temperature distribution uniformity of the reaction area, thereby avoiding the problems of excessive ablation of micropores caused by local high temperature or insufficient activation in low temperature areas; the preheated heat-carrying particles provide a continuous and stable heat source for the activation reaction, and improve the uniformity of the micropore structure of the porous carbon.

[0032] Specifically, the fluidized bed reaction unit comprises: a reaction tank for providing a reaction site for the activation reaction; a particle pre-distributor 14 arranged inside the reaction tank for reducing the entering speed of the heat-carrying particles; a gradient gas distributor 7 arranged below the particle pre-distributor for forming a gradient gas flow of the activation gas to mix the reaction raw materials and the heat-carrying particles; a metal filter arranged at the top of the reaction tank for filtering the carbon powder in the reaction tail gas.

[0033] Specifically, the metal filter is provided with a pulse gas backflushing device, and the pulse gas backflushing device comprises four nitrogen pulse backflushing filters 13.

[0034] Specifically, the heat-carrying particle inlet 16 is provided with a high-temperature valve for adjusting the flow of the heat-carrying particles.

[0035] Optionally, the optional embodiment of the high-temperature valve comprises any one of a slide valve, a gate valve and a ball valve, and the valve core of the high-temperature valve is a water-cooled jacket type valve core.

[0036] In the implementation, the system of the present application introduces high-temperature alumina, silicon dioxide and metal particles into the fluidized bed reaction unit by the heat-carrying particle circulation unit, utilizes the high heat capacity and good heat transfer performance thereof, significantly improves the temperature uniformity of the activation reaction area, and thereby improves the specific surface area and microporosity of the porous carbon; the circulation use of the heat-carrying particles not only improves the heat energy utilization rate and reduces the overall energy consumption, but also enhances the continuous operation capacity of the system and prolongs the operation cycle.

[0037] Specifically, the discharging mode of the cooling and discharging unit is a pressure feeding type pneumatic conveying discharging mode, and in this embodiment, a Venturi feeder can be used for conveying.

[0038] Specifically, the bottom of the cyclone separator 19 is provided with a gas ring pipe 6, and the gas in the gas ring pipe 6 is nitrogen.

[0039] Specifically, the conveying separation unit can perform gas conveying by a conveying fan and / or belt conveying of the heat-carrying particles by a conveying belt.

[0040] Specifically, the activation gas supply unit comprises: a gas mixing tank 21 for mixing the reaction tail gas and the activation gas to form mixed activation gas; a plurality of flow meters 11 connected to the gas mixing tank for respectively detecting the flow rates of the activation gas, the reaction tail gas and the mixed activation gas; a gas preheating furnace 12 connected to the gas mixing tank for heating the mixed activation gas.

[0041] Specifically, the heating mode of the gas preheating furnace 12 adopts any one or a combination of tail gas waste heat heating, resistance heating and natural gas combustion heating.

[0042] Specifically, the tail gas conveying unit comprises: a tail gas conveying pipeline 20 connected to the gas mixing tank; a circulating fan 10 connected to the tail gas conveying pipeline 20 for conveying the reaction tail gas to the gas mixing tank.

[0043] Specifically, the volume ratio of the reaction tail gas to the activation gas in the gas mixing tank is 3:7-5:5.

[0044] Specifically, the gas types of the activation gas include water vapor and carbon dioxide.

[0045] In implementation, the system of the present application realizes gradient distribution of the activation gas in the fluidized bed by setting a particle pre-distributor, a gradient gas distributor and a metal filter, improves the gas-solid contact efficiency; through the setting of the circulating fan and the tail gas conveying pipeline, through the recycling of the tail gas, the components in the reaction tail gas that are not completely reacted can participate in the reaction again, which not only improves the utilization rate of raw materials, but also reduces the environmental pollution caused by the discharge of reaction tail gas, through the further heating of the tail gas waste heat, reduces the energy consumption, and increases the temperature uniformity of the mixed gas.

[0046] Specifically, the fluidized bed reaction unit further comprises a conveying port assembly, and the conveying port assembly is provided at positions from top to bottom of the reaction tank 5 respectively as a reaction tail gas outlet 15, a heat-carrying particle inlet 16, a heat-carrying particle outlet 18 and a gas inlet 17.

[0047] In the implementation, the system described in the application avoids the blockage and wear caused by traditional mechanical conveying, improves the continuity and stability of the feeding and discharging process, and reduces the escape of fine particles with tail gas by setting a metal filter, thereby improving the stability of the normal operation of the equipment.

[0048] Example 1: Preparation of petroleum coke-based high specific surface area porous carbon by porous carbon activation system with heat-carrying particle circulation.

[0049] In this example, a Φ800mm×6000mm reactor tank is used, and the bottom temperature of the four-stage precise temperature control heating buffer tank is 950℃, the middle temperature is 900℃, the upper temperature is 850℃, and the separation zone temperature is 800℃. The high-temperature sliding valve is used, wherein the water-cooling flow rate of the valve core is 15L / min, the cooling medium temperature is 20℃, the control heat-carrying particle circulation flow rate is 15kg / min, the bed temperature field is self-balanced, that is, the bed temperature difference is controlled within ±5℃, the heat-carrying particle circulation unit uses spherical Al2O3 particles with a particle size of 100±5μm, and the bulk density is 1.32g / cm 3 The recovery rate is 99.5% and the entrainment rate is not more than 0.5% in the fluidized bed.

[0050] The working parameters of the heat-carrying particle circulation porous carbon activation system in this example are as follows: ultra-fine petroleum coke powder with a particle size of 5-8μm is fed at a feeding rate of 12kg / h by pressure pneumatic conveying, mixed with preheated reaction tail gas at 200℃, and the preheating energy consumption of the raw material is reduced by 25%; the gas mixing tank is connected to mixed activation gas with a volume ratio of 7:3 of water vapor and reaction tail gas, and the activation is carried out at 900℃ for 7 hours; the gradient gas distributor forms a gradient gas flow with a superficial gas velocity of 0.10m / s, and the dynamic heat conduction of the heat-carrying particles improves the uniformity of the reaction zone temperature by 90%, reduces the micropore ablation caused by local high temperature in the traditional process, and realizes; switch to activation gas with a volume ratio of 6:4 of CO2 and N2, and activate at 850℃ for 5 hours, the superficial gas velocity is reduced to 0.08m / s, the metal filter is matched with a pulse nitrogen backwashing device with a pressure of 0.5MPa and a frequency of 1Hz, and the ultra-fine carbon powder is separated without blockage; 40% of the reaction tail gas is burned in the combustion jacket at a temperature of 850℃ to produce fuel for preheating of the raw material, and the waste heat recovery rate reaches 65%.

[0051] Example 2: Preparation of phenolic resin-based narrow mesoporous carbon by porous carbon activation system with heat-carrying particle circulation.

[0052] In this example, a Φ600mm reactor tank is used, and the particle size of the phenolic resin carbonization material aggregate is 2-3μm, which is broken to a dispersion degree of not less than 95%, and the bed radial temperature difference is reduced from ±50℃ in the traditional process to ±8℃; the heat-carrying particle circulation unit uses spherical SiO2 particles with a particle size of 80μm.

[0053] The working parameters of the porous carbon activation system with heat-carrying particle circulation in this embodiment are as follows: through tail gas afterheat heating, the circulating fan delivers 800 DEG C reaction tail gas to the gas mixing tank, and after mixing with the activation gas, the raw material is preheated from 25 DEG C to 550 DEG C, and the energy consumption is reduced by 40% compared with electric heating; CO2 is activated at 920 DEG C for 3 hours, the superficial gas velocity is 0.15 m / s, the mass ratio of heat-carrying particles to reaction raw material is 8:1, and uniform mixing is realized through the particle pre-distributor; the mixed activation gas with a volume ratio of 5:5 of water vapor and reaction tail gas is switched, and activated at 780 DEG C for 4 hours, the superficial gas velocity is 0.12 m / s, the stirring paddle speed is 15 rpm, and the particle caking is inhibited; the metal filter uses 0.3 mu m aperture stainless steel 310s, cooperates with 0.5 MPa nitrogen back flushing, and the superfine carbon powder recovery rate reaches 99.9%; the pore size of the porous carbon is concentrated in 3-5 nm, and the proportion is 90%, and the tap density is 0.75 g / cm3.

[0054] Example 3: Preparation of coconut shell biomass carbon graded pore structure by porous carbon activation system with heat-carrying particle circulation.

[0055] The heat-carrying particle circulation unit in this embodiment selects gamma-Al2O3 with a particle size of 90 mu m, and the surface is coated with a carbon layer of 2 nm, which isolates alkali metals.

[0056] The working parameters of the porous carbon activation system with heat-carrying particle circulation in this embodiment are as follows: the gradient gas distributor is connected to the mixed activation gas with a volume ratio of 7:3 of water vapor and reaction tail gas in the first stage, activated at 880 DEG C for 5 hours, the micropore formation rate is 200 m² / g•h; the gradient gas distributor is connected to the mixed activation gas with a volume ratio of 6:4 of CO2 and N2 in the second stage, activated at 820 DEG C for 3 hours, the superficial gas velocity of the mixed activation gas is 0.07 m / s, and the heat is supplied by the heat-carrying particle circulation and the porous carbon particles are dispersed, so that the adjacent micropores are connected to form 2-50 nm mesopores, and the proportion of mesopores is 30%.

[0057] In summary, the three examples verify that this embodiment is suitable for multiple types of raw materials such as petroleum coke, phenolic resin and coconut shell, and efficient activation is realized through heat-carrying particle selection and process adjustment.

[0058] So far, the technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to related technical features without departing from the principles of the present application, and the technical schemes after these changes or replacements will fall within the protection scope of the present application.

Claims

1. A porous carbon activation system with circulating heat-carrying particles, characterized in that, include: Fluidized bed reaction unit is used to activate the reactants through activating gas and heat-carrying particles to convert them into porous carbon; A cooling and unloading unit, which is connected to the fluidized bed reaction unit, is used to cool the output porous carbon. A feeding unit, which is located above the cooling and unloading unit, is used to transport the reaction raw materials, including a raw material tank for loading the reaction raw materials and a discharge valve connected to the raw material tank for controlling whether the raw materials are transported. The exhaust gas conveying unit is connected to the fluidized bed reaction unit and is used to collect the reaction exhaust gas formed after the activation reaction. An activation gas supply unit, which is connected to the tail gas delivery unit, is used to transfer the heat of the reaction tail gas to the activation gas for preheating and mixing with the activation gas to output a mixed activation gas. A conveying and separating unit, connected to the fluidized bed reaction unit, is used to convey the heated heat-carrying particles to the activation reaction zone in the fluidized bed reaction unit to provide the heat required for the activation reaction. It includes a riser pipe vertically installed outside the raw material tank to provide conveying pressure for the heat-carrying particles by introducing nitrogen into the fluidized bed reaction unit, a cyclone separator connected to the riser pipe to separate the heat-carrying particles from the porous carbon, and a conveying fan connected to the cyclone separator to provide conveying power for the separated heat-carrying particles. A heat-carrying particle heating unit, which is connected to the conveying and separating unit, is used to heat the heat-carrying particles that have not entered the fluidized bed reaction unit. It includes a heating buffer tank connected to the riser to reduce the pressure of the input nitrogen and to heat the heat-carrying particles, and a heating furnace connected to the heating buffer tank to heat the heating buffer tank.

2. The porous carbon activation system with circulating heat-carrying particles according to claim 1, characterized in that, The heat-carrying particles include at least one of alumina, silicon dioxide, zirconium oxide, and silicon carbide.

3. The porous carbon activation system with circulating heat-carrying particles according to claim 2, characterized in that, The fluidized bed reaction unit includes: A reaction vessel is used to provide a reaction site for activation reactions; A particle pre-distributor, which is disposed inside the reaction vessel, is used to reduce the entry velocity of the heat-carrying particles; A gradient gas distributor is disposed below the particle pre-distributor to form a gradient gas flow of the activation gas to mix the reactants and the heat-carrying particles; A metal filter, located at the top of the reaction vessel, is used to filter carbon powder in the reaction exhaust gas.

4. The porous carbon activation system with circulating heat-carrying particles according to claim 3, characterized in that, The unloading method of the cooling unloading unit is the pressure conveying pneumatic conveying unloading method.

5. The porous carbon activation system with circulating heat-carrying particles according to claim 4, characterized in that, The activation gas supply unit includes: A gas mixing vessel is used to mix the reaction tail gas and the activation gas to form a mixed activation gas; Several flow meters are connected to the gas mixing tank to detect the flow rates of the activation gas, the reaction tail gas, and the mixed activation gas, respectively. A gas preheating furnace, connected to the gas mixing tank, is used to heat the mixed activation gas.

6. The porous carbon activation system with circulating heat-carrying particles according to claim 5, characterized in that, The exhaust gas delivery unit includes: An exhaust gas delivery pipeline, which is connected to the gas mixing tank; A circulating fan, connected to the exhaust gas delivery pipeline, is used to deliver the reaction exhaust gas to the gas mixing tank.

7. The porous carbon activation system with circulating heat-carrying particles according to claim 6, characterized in that, The volume ratio of the reaction tail gas to the activation gas in the gas mixing tank is 3:7 to 5:

5.

8. The porous carbon activation system with heat-carrying particle circulation according to claim 7, characterized in that, The types of activated gases include water vapor and carbon dioxide.

9. The porous carbon activation system with circulating heat-carrying particles according to claim 8, characterized in that, The fluidized bed reaction unit also includes a conveying port assembly, which is positioned from top to bottom in the reaction vessel as the reaction tail gas outlet, the heat-carrying particle inlet, the heat-carrying particle outlet, and the gas inlet.

10. The porous carbon activation system with circulating heat-carrying particles according to claim 9, characterized in that, The inlet of the heat-carrying particles is equipped with a high-temperature valve for regulating the flow rate of the heat-carrying particles.

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