Porous carbon activation method

Abstract

The present invention relates to the technical field of chemical equipment, particularly to a porous carbon activation method, which comprises: inputting a carbon raw material and a preset reaction gas into a fluidized bed reaction device to carry out an activation reaction to prepare porous carbon, and the fluidized bed reaction device comprises a feeding tank, a raw material preheating furnace, a reactor, a heating unit and a discharging tank, a gas distributor, a stirring paddle, a cyclone separator and / or a metal filter column are arranged in the reactor; the activation method comprises the following steps: S1, conveying a carbon raw material to a raw material preheating furnace, and preheating in an inert atmosphere; s2, conveying the preheated carbon raw material into a reactor, introducing reaction gas under a preset activation condition, and carrying out an activation reaction to obtain activated porous carbon; s3, under the protection of an inert atmosphere, conveying the activated porous carbon to a discharging tank, cooling, and discharging to obtain a porous carbon product; through stepped activation and multi-section temperature control design, the problems of poor product uniformity and high energy consumption of a traditional process are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous carbon activation, and particularly relates to a porous carbon activation method. BACKGROUND

[0002] Porous carbon materials have unique pore structures and surface properties, and exhibit irreplaceable application value in the fields of energy storage, environmental governance, chemical catalysis, etc. The demand for high-performance porous carbon materials is increasing in the current industry, especially in high-end application scenarios such as new energy batteries and gas adsorption separation, which puts forward more stringent requirements for the specific surface area, pore size distribution and structural stability of the materials. However, the traditional physical activation technology faces insurmountable technical bottlenecks in the process of expanding to industrial scale, which restricts the large-scale production of high-quality porous carbon materials.

[0003] In the prior art, the physical activation method is widely concerned due to its environmental friendly characteristics, but there is a common problem of insufficient control accuracy of the reaction process. When the conventional activation equipment is scaled up, the uneven distribution of the flow field and temperature field in the reactor often leads to significant fluctuations in product performance. This phenomenon is particularly prominent in the activation process of ultra-fine powders, and the agglomeration tendency of raw material particles exacerbates the decline in gas-solid contact efficiency, thereby affecting the uniformity of the activation reaction. At the same time, the inherent high energy consumption characteristics of the physical activation process have not been effectively improved, and a large amount of heat energy is dissipated through the reactor wall, and the utilization efficiency of the reaction gas also needs to be improved.

[0004] Chinese Patent Publication No. CN118702098A discloses a porous carbon material and its preparation method and application, which comprises: providing a mixed slurry containing a carbon precursor and a seed crystal inducer, and carbonizing the mixed slurry to obtain a pre-carbonized precursor material; physically activating the pre-carbonized precursor material to form pores to obtain a porous carbon precursor material; and sintering the porous carbon precursor material by using ultrafast ultra-high temperature sintering technology to obtain a porous carbon material.

[0005] It can be seen that this scheme has obvious limitations in the regulation ability of the pore structure of the porous carbon material, lacks dynamic regulation ability of the activation process, and cannot optimize the process parameters in real time according to the reaction process, resulting in significant deviation of the pore characteristics of the final product from the design target. This lack of regulation ability seriously limits the application potential of porous carbon materials in high-end fields. SUMMARY

[0006] To this end, the present application provides a porous carbon activation method to overcome the problems of poor gas-solid contact efficiency, inaccurate pore size distribution control, uneven product performance, and high energy consumption in the activation process of porous carbon in the prior art, especially for the stringent requirements of specific surface area and pore structure of porous carbon materials for high-end application scenarios such as lithium battery negative electrode materials, a highly efficient porous carbon activation method that can be industrialized is provided.

[0007] To achieve the above-mentioned purpose, the present application provides a porous carbon activation method, comprising: Step S1, the carbon raw material is transported to the raw material preheating furnace for preheating under an inert atmosphere; Step S2, the preheated carbon raw material is transported to the reactor, and the reaction gas is introduced for activation reaction under the preset activation condition, to obtain the activated porous carbon; Step S3, the activated porous carbon is transported to the discharge tank for cooling under the protection of an inert atmosphere, and then discharged to obtain the porous carbon product; In the step S2, the activation condition includes the activation reaction temperature, the activation reaction time and the activation mode, and the activation mode includes a one-step activation mode using a single activation gas for reaction and a stepwise activation mode using two kinds of activation gases alternately for reaction. The fluidized bed reaction device for porous carbon activation includes a feeding tank, a raw material preheating furnace, a reactor, a heating unit and a discharge tank, the reactor is internally provided with a gas distributor, a stirring paddle, a cyclone separator and / or a metal filter column, and the reactor includes a straight cylinder section and an enlarged section.

[0008] Further, in the step S2, the reaction gas is a mixed gas of activation gas and carrier gas, wherein, The activation gas includes one or more of water vapor, The carrier gas includes one or more of nitrogen, argon, helium and reaction tail gas; The apparent velocity of the total gas in the activation reaction is controlled to be 0.01 m / s-0.3 m / s.

[0009] Further, in the step S2, The activation gas in the reaction gas accounts for 10%-100% of the total gas amount of the carrier gas and the activation gas; When the one-step activation mode is used, a single activation gas is used for reaction, and the activation reaction time is 5h-15h, wherein the single activation gas is water vapor or ; When the stepwise activation mode is used, two kinds of activation gases are used alternately for activation reaction, and the activation reaction time of each kind of activation gas is 3h-10h.

[0010] Further, in the step S1, the preheating temperature of the carbon raw material is 300-700 DEG C; the particle size of the carbon raw material is less than or equal to 200 microns; the specific surface area of the carbon raw material is less than or equal to 800 ; The raw material preheating furnace adopts any one of a rotary furnace, a fluidized bed and a moving bed; the heating mode of the heating unit includes any one of electric heating, natural gas combustion heating and reaction tail gas waste heat heating.

[0011] Further, in the step S3, the following steps are included: The activated porous carbon is transported to the discharge tank after being cooled to 600 DEG C + / - 100 DEG C or without cooling under inert atmosphere protection, and is discharged after being cooled to below 50 DEG C, to obtain a porous carbon product.

[0012] Further, in the step S2, the activation reaction temperature is 700-1200 DEG C, and the activation reaction time is 5-15 hours.

[0013] Further, the carbon raw material includes one or more of biomass carbon, pitch carbon, petroleum coke and phenolic resin; the particle size of the carbon raw material is less than or equal to 200 microns; the specific surface area of the carbon raw material is less than or equal to 800 .

[0014] Further, in the step S2, when the stepwise activation mode is used, two kinds of activation gases are alternately used for activation reaction, first using water vapor as the activation gas for activation reaction, and then using as the activation gas for activation reaction, wherein the activation reaction time of each kind of activation gas is 5-10 hours.

[0015] Further, the reactor is multiple, wherein, Each of the reactors is arranged in series, and the carbon raw material is sequentially activated in each of the reactors with independent temperature control; Or, each of the reactors is arranged in parallel, and the carbon raw material is activated in each of the reactors with independent temperature control.

[0016] Further, the cavity of the reactor includes a straight cylinder section and an enlarged section arranged at the upper part of the straight cylinder section. The reactor includes multiple reaction regions with independent temperature control.

[0017] Compared with the prior art, the porous carbon product prepared by the activation method of the present application has significantly improved performance; the stepwise activation process design of the present application realizes precise control of the pore size structure of the porous carbon material; water vapor and are used for phased activation, first using water vapor to efficiently create pores at high temperature, and then using The pore expansion modification can obtain a specific surface area of greater than or equal to 1800 The high-quality porous carbon product has a controllable pore size distribution, and the ratio of micropores to mesopores can be flexibly adjusted according to application requirements, and is particularly suitable as a high-performance lithium battery negative carrier material compared with a traditional single-stage activation process.

[0018] Further, the activation method of the present application innovatively adopts a multi-stage fluidized bed reactor design, which successfully solves the problems of agglomeration and channeling of ultra-fine carbon raw materials (2-10 μm) in the fluidization process through the combination of straight sections and enlarged sections, in combination with high-efficiency gas distributors and stirring systems; the multi-stage independent temperature control system ensures a small temperature difference fluctuation in the axial and radial directions of the reactor, significantly improving the product consistency during industrialization.

[0019] Further, the activation method and device provided by the present application have excellent scalability, and the amplification factor from the laboratory to the industrial production can reach more than 100 times, and the product performance can be kept stable; the matching weighing and metering system realizes accurate control of process parameters, and the production process has high automation degree; the method is suitable for various raw materials such as biomass carbon and pitch carbon, and the product can meet the strict requirements of high-end application fields such as supercapacitors, lithium ion batteries, and gas adsorption on porous carbon materials, and has a broad market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The schematic diagram of the fluidized bed reaction device for porous carbon activation provided by the present application for examples 1-6 is shown in the figure; Figure 2 The schematic diagram of the fluidized bed reaction device for porous carbon activation provided by the present application for examples 7-8 is shown in the figure; Figure 3 The step flow chart of the porous carbon activation method provided by the present application is shown in the figure; 101, feeding tank, 102, discharging tank, 103, material collecting tank, 104, raw material preheating furnace, 105, gas distributor, 106, stirring paddle, 107, metal filter column, 108, alkali absorption device, 109, stirring motor. DETAILED DESCRIPTION

[0021] In order to make the purpose and advantages of the present application more clear and explicit, the present application will be further described below in combination with examples; it should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0022] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these 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 indicate the direction or positional relationship of the terms 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 particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0024] Referring to Figure 1 and Figure 2 The embodiment of the present application provides a fluidized bed reaction device for porous carbon activation, and the specific technical scheme of the fluidized bed reaction device comprises: The feeding tank 101 is used for storing and quantitatively conveying the carbon raw material; The raw material preheating furnace 104 adopts a rotary furnace, a fluidized bed or a moving bed form to heat the carbon raw material; The reactor is internally provided with a gas distributor 105 for ensuring uniform distribution of the activation gas, a stirring paddle 106 for preventing agglomeration of ultrafine particles, a cyclone separator and / or a metal filter column 107 for realizing efficient gas-solid separation; The heating unit can be designed with multiple independent temperature control sections to heat the raw material preheating furnace 104 and the reactor, and can adopt electric heating, natural gas combustion heating or reaction tail gas waste heat heating; The discharge tank 102 is filled with inert gas, and the porous carbon after activation is discharged at high temperature under the protection of the inert gas.

[0025] Specifically, the reactor can adopt a multi-section structure design, which comprises: a multi-stage independently temperature-controlled reaction area, and / or a plurality of independently temperature-controlled reactors arranged in series or in parallel.

[0026] Specifically, the multi-section structure comprises a unique structure design of a straight cylinder section and an enlarged section. The multi-stage independent temperature control can independently provide the heating temperature set for the straight cylinder section and the enlarged section of the reactor, respectively.

[0027] The entire device system is equipped with a weighing and metering system for carbon raw material and porous carbon product to realize accurate quality control. It can be understood that the weighing and metering device can be arranged in the feeding tank, the raw material preheating furnace, the reactor and the discharge tank to weigh the weight of the product at each stage of the reaction.

[0028] In a specific embodiment, referring to Figure 1 The fluidized bed reaction device for porous carbon activation provided by the embodiments 1-6 of the present application is shown in the schematic diagram; Figure 1 The fluidized bed reaction device is provided with one reactor, and the diagram comprises: The feeding tank 101, the raw material preheating furnace 104 connected with the carbon raw material output end of the feeding tank, the reactor connected with the carbon raw material output port of the raw material preheating furnace 104, the gas distributor 105, the stirring paddle 106 and the stirring motor 109 arranged in the straight cylinder section of the reactor, the metal filter column 107 (separation component) arranged in the upper part of the expanded end section of the reactor, the alkali liquor absorption device 108 connected with the metal filter column 107, the output port of the porous carbon arranged in the lower part of the reactor, the output port connected with the discharge tank 102, the discharge port of the discharge tank 102 connected with the material collecting tank 103, and the porous carbon product prepared is stored in the material collecting tank 103.

[0029] In another specific embodiment, referring to Figure 2 Fig. 7 shows a schematic diagram of the fluidized bed reaction device for porous carbon activation provided by the embodiment 7-8 of the present application. Figure 2 The fluidized bed reaction device in the embodiment 7-8 of the present application is provided with two reactors, and the diagram includes: The feeding tank 101, the raw material preheating furnace 104 connected with the carbon raw material output end of the feeding tank, the first reactor connected with the carbon raw material output port of the raw material preheating furnace 104, the second reactor connected with the carbon raw material output port of the first reactor, the gas distributor 105, the stirring paddle 106 and the stirring motor 109 arranged in the straight cylinder section of the first reactor and the second reactor, the metal filter column 107 (separation component) arranged in the upper part of the expanded end section of the first reactor and the second reactor, the output port of the porous carbon arranged in the lower part of the second reactor, the output port connected with the discharge tank 102, the discharge port of the discharge tank 102 connected with the material collecting tank 103, and the porous carbon product prepared is stored in the material collecting tank 103.

[0030] Referring to Figure 3 Fig. 8 shows a step flow chart of the porous carbon activation method provided by the present application, and the embodiment of the present application further provides a method for porous carbon activation by using the above device, which includes the following steps: Step S1, carbon raw material preheating: The carbon raw material (including but not limited to biomass carbon, pitch carbon, petroleum coke, phenolic resin, etc.) is conveyed to the raw material preheating furnace through the feeding tank, heated to 300-700℃ under the inert atmosphere of nitrogen, etc. for pretreatment. The particle size of the carbon raw material is controlled below 200 μm, preferably below 100 μm, and most preferably 2-10 μm; the specific surface area of the carbon raw material is controlled below 800 The specific surface area of the carbon raw material is preferably controlled below 400 The specific surface area of the carbon raw material is preferably controlled below 400

[0031] Step S2, fluidized activation reaction: The preheated carbon raw material is conveyed to the reactor, and the reaction gas is introduced under the preset activation condition for activation reaction, so as to obtain the activated porous carbon; Specifically, the preset activation conditions include: activation reaction temperature, activation reaction time length, and activation mode. Specifically, the preheated carbon raw material is transported into the reactor, and the activation reaction is carried out in the temperature range of 700-1200°C (activation reaction temperature) by using the mixed gas of the activation gas (water vapor and / or ) and the carrier gas (nitrogen, argon, helium, or one or more of the reaction tail gas) to carry out the activation reaction for 5-15 hours. It can be understood that the reaction tail gas is the gas in the reactor after being filtered by the metal filter column 107 and / or treated by the lye absorption device 108.

[0032] Specifically, the gas superficial velocity of the total gas in the activation reaction is controlled at 0.01-0.3 m / s, and preferably, controlled at 0.04-0.12 m / s. Specifically, the activation gas accounts for 10%-100% of the total gas amount of the carrier gas and the activation gas, and the ratio is the volume ratio under the same temperature condition.

[0033] Specifically, the activation mode includes: One-step activation mode: only a single activation gas (water vapor or ) is used; Stepwise activation mode: two kinds of activation gases are alternately used, preferably, water vapor is used as the activation gas first to carry out the activation reaction for 3-10 hours, and then is used as the activation gas to carry out the activation reaction for 3-10 hours.

[0034] Step S3: product unloading: The activated porous carbon is transported to the unloading tank under the protection of an inert atmosphere, cooled, and then unloaded to obtain the porous carbon product; Specifically, the activated porous carbon product is transported to the unloading tank at a high temperature (600°C±100°C) or directly without cooling under the protection of an inert atmosphere, and then unloaded after being cooled to below 50°C.

[0035] Please refer to Figure 1 and Figure 2 for further detailed description of the features and properties of the present application in combination with the following examples;

[0036] Example 1:

[0037] In this embodiment, the device shown in Figure 1 is used, and the carbon raw material is coconut shell carbon (one kind of biomass carbon), which is crushed and sieved to obtain a powder with a particle size of 5-8 μm. First, the raw material is pretreated in the raw material preheating furnace of the fluidized bed reaction device under nitrogen protection to 500°C for 1 hour, and then transferred to the reactor for stepwise activation.

[0038] In the stepwise activation mode, the first stage is carried out at 900℃, with water vapor and nitrogen mixed gas (volume ratio 6:4) being introduced into the reactor, the apparent gas velocity is controlled at 0.08m / s, and the activation is continued for 8 hours; The second stage is adjusted to 850℃, with water vapor and nitrogen mixed gas (volume ratio 1:1) being introduced into the reactor, the apparent gas velocity is controlled at 0.06m / s, and the activation is continued for 6 hours.

[0039] After the activation reaction is completed, the product is unloaded at a high temperature of 600℃ under the protection of nitrogen, and finally a high-quality porous carbon with a specific surface area of 1920m² / g, a micropore rate of 65%, and a yield of 28% is obtained.

[0040] Example 2: In this embodiment, the device shown in Figure 1 is used, and the carbon raw material is petroleum coke which is superfine ground to a particle size range of 10-15μm. After the raw material is preheated to 400℃ by the preheating furnace of the fluidized bed reaction device under the protection of argon, pure water vapor is directly introduced. One-step activation is carried out at an activation temperature of 950℃, with the apparent gas velocity being controlled at 0.12m / s, and the activation reaction time is 12 hours. The obtained product has a specific surface area of 1450m² / g, a micropore rate of 75%, and a yield of 32%, and is particularly suitable as a catalyst carrier material.

[0041] Example 3:

[0042] In this embodiment, the device shown in Figure 1 is used, and the carbon raw material is mesophase pitch (pitch carbon) with a particle size of 10-15μm. Under the protection of nitrogen, the preheating treatment is carried out at a temperature increasing rate of 5℃ / min to 450℃, and then the stepwise activation is carried out in the fluidized bed reactor: The first stage uses water vapor and nitrogen mixed gas (volume ratio 7:3) to activate at 880℃ for 6 hours (apparent gas velocity 0.08 ); The second stage switches to water vapor and nitrogen mixed gas (volume ratio 5:5) to activate at 920℃ for 4 hours (apparent gas velocity 0.06m / s).

[0043] The product maintains a fiber morphology, with a specific surface area of 1850m² / g, an axial electrical conductivity of 320S / cm, a radial electrical conductivity of 85S / cm, and a yield of 29%, and is particularly suitable as an anisotropic electrode material.

[0044] Example 4:

[0045] In this embodiment, the device shown in Figure 1 ​The apparatus shown uses biochar obtained by crushing walnut shells to 50-100 μm and then carbonizing them at 600°C under nitrogen protection for 4 hours. The pretreated biochar undergoes staged activation in a fluidized bed reactor, wherein: In the first stage, a mixture of steam and nitrogen (volume ratio 8:2) was introduced into the reactor and activated at 950°C for 5 hours (apparent gas velocity 0.12 m / s). The second stage involves introducing [a process] into the reactor. The mixture of nitrogen and nitrogen (volume ratio 6:4) was activated at 900°C for 3 hours (apparent gas velocity 0.09 m / s).

[0046] Under nitrogen protection and high-temperature direct unloading, the resulting porous carbon has a typical hierarchical pore structure, a specific surface area of ​​1750 m² / g, a micropore / mesopore ratio of 1:1, and an adsorption capacity of 850 mg / g for methylene blue.

[0047] Example 5:

[0048] In this embodiment, the following is adopted: Figure 1 The apparatus shown uses delayed petroleum coke as the carbon feedstock, which is obtained as 5-10 μm powder through air jet milling. After preheating to 500°C under the protection of the reaction tail gas atmosphere, a step-by-step activation process is carried out: First, activate the mixture of water vapor and nitrogen (30% by volume) at 850℃ for 6 hours (apparent gas velocity 0.05m / s). Then purified at 900℃ Activation time: 8 hours (gas velocity: 0.1 m / s).

[0049] The product has a pore size concentrated in the range of 3-5 nm, a specific surface area of ​​1550 m² / g, a mesoporous rate of 82%, and a yield of 33%, making it particularly suitable as a support for macromolecular catalytic reactions.

[0050] Example 6:

[0051] In this embodiment, the following is adopted: Figure 1 The apparatus shown uses low molecular weight phenolic resin as the carbon raw material. The low molecular weight phenolic resin is cured at 300℃ and then pulverized to 2-5 μm. Preheating and carbonization are carried out under nitrogen protection at a rate of 2℃ / min to 700℃ for 5 hours, followed by a single activation step. Activation was performed at 800℃ for 10 hours using a mixture of water vapor and argon (volume ratio 4:6) (apparent gas velocity 0.04 m / s).

[0052] The obtained product is mainly composed of ultramicropores (pore size 0.5-1nm), with a specific surface area of ​​2100m² / g, a microporosity of 92%, and a yield of 25%.

[0053] Example 7:

[0054] In this embodiment, the device shown in Figure 2 The carbon raw material is phenolic resin carbonization material. The phenolic resin carbonization material (particle size 2-5 μm) is heated to 600°C in the raw material preheating furnace of the fluidized bed reaction device using the waste heat of the reaction tail gas. Then, it is sequentially passed through two independently temperature-controlled reaction zones (two reaction zones are arranged in two reactors respectively) for stepwise activation: The first reaction zone of the first reactor is maintained at a temperature of 800°C, and mixed steam and nitrogen (1:1) activation is carried out for 6 hours (superficial gas velocity 0.05 m / s); The second reaction zone of the second reactor is maintained at a temperature of 900°C, and mixed with argon (3:7) for 4 hours (superficial gas velocity 0.1 m / s).

[0055] The final product is unloaded under the protection of nitrogen at 600°C, and a narrow distribution porous carbon with concentrated pore size distribution (1-3 nm), specific surface area 2100 m² / g, and yield 26% is obtained.

[0056] Example 8:

[0057] In this embodiment, the device shown in Figure 2 The carbon raw material is a composite precursor (particle size 3-8 μm) obtained by co-milling petroleum coke and phenolic resin at a mass ratio of 7:3. After preheating for 4 hours at 700°C under nitrogen protection, stepwise activation is carried out: The first stage uses mixed steam and nitrogen gas (volume ratio 6:4) at 900°C for 5 hours in the first reactor (superficial gas velocity 0.07 m / s); The second stage switches to mixed with argon gas (volume ratio 4:6) at 850°C for 5 hours in the second reactor (superficial gas velocity 0.05 m / s).

[0058] The final product is unloaded under the protection of nitrogen at 600°C, and the product has high graphitization degree (ID / IG=0.85) of petroleum coke and high porosity of resin carbon, specific surface area 1950 m² / g, yield 30%, and excellent rate performance.

[0059] Example 9:

[0060] In this embodiment, the device shown in Figure 1 The carbon raw material is coconut shell carbon (a kind of biomass carbon), which is crushed and sieved to obtain a powder with a particle size of 5-8 μm. First, it is preheated to 500°C in the raw material preheating furnace of the fluidized bed reaction device under nitrogen protection for 1 hour, and then transferred to the reactor for stepwise activation.

[0061] In the process of the stepwise activation mode, the first stage was carried out at 900℃, with the mixed gas of water vapor and nitrogen (volume ratio 1:9) being introduced into the reactor, the superficial gas velocity being controlled at 0.3m / s, and the activation being continued for 10 hours; The second stage was adjusted to be carried out at 850℃, with the mixed gas of water vapor and nitrogen (volume ratio 1:1) being introduced into the reactor, the superficial gas velocity being controlled at 0.06m / s, and the activation being continued for 5 hours. The second stage was adjusted to be carried out at 850℃, with the mixed gas of water vapor and nitrogen (volume ratio 1:1) being introduced into the reactor, the superficial gas velocity being controlled at 0.06m / s, and the activation being continued for 5 hours.

[0062] After the activation reaction was completed, the product was unloaded under the protection of nitrogen at a high temperature of 600℃, and finally high-quality porous carbon with a specific surface area of 1540m² / g, micropore rate of 63% and yield of 29% was obtained.

[0063] Example 10: In this example, the device shown in Figure 1 was used, and the carbon raw material was coconut shell carbon (one kind of biomass carbon), which was crushed and sieved to obtain powder with a particle size of 5-8μm. First, the raw material was pretreated in the raw material preheating furnace of the fluidized bed reaction device under the protection of nitrogen at a temperature of 500℃ for 1 hour, and then was transferred into the reactor for stepwise activation.

[0064] In the process of the stepwise activation mode, the first stage was carried out at 900℃, with the mixed gas of water vapor and nitrogen (volume ratio 6:4) being introduced into the reactor, the superficial gas velocity being controlled at 0.08m / s, and the activation being continued for 5 hours; The second stage was adjusted to be carried out at 850℃, with the mixed gas of water vapor and nitrogen (volume ratio 6:4) being introduced into the reactor, the superficial gas velocity being controlled at 0.01m / s, and the activation being continued for 10 hours. The second stage was adjusted to be carried out at 850℃, with the mixed gas of water vapor and nitrogen (volume ratio 6:4) being introduced into the reactor, the superficial gas velocity being controlled at 0.01m / s, and the activation being continued for 10 hours.

[0065] After the activation reaction was completed, the product was unloaded under the protection of nitrogen at a high temperature of 600℃, and finally high-quality porous carbon with a specific surface area of 1540m² / g, micropore rate of 63% and yield of 29% was obtained.

[0066] Example 11: In this example, the device shown in Figure 1 was used, and the carbon raw material was coconut shell carbon (one kind of biomass carbon), which was crushed and sieved to obtain powder with a particle size of 5-8μm. First, the raw material was pretreated in the raw material preheating furnace of the fluidized bed reaction device under the protection of nitrogen at a temperature of 700℃ for 1 hour, and then was transferred into the reactor for stepwise activation.

[0067] In the process of the stepwise activation mode, the first stage was carried out at 900℃, with the mixed gas of water vapor and nitrogen (volume ratio 6:4) being introduced into the reactor, the superficial gas velocity being controlled at 0.08m / s, and the activation being continued for 5 hours; The second stage was adjusted to be carried out at 850℃, with the mixed gas of water vapor and nitrogen (volume ratio 6:4) being introduced into the reactor, the superficial gas velocity being controlled at 0.01m / s, and the activation being continued for 10 hours. The second stage was adjusted to be carried out at 850℃, with the mixed gas of water vapor and nitrogen (volume ratio 6:4) being introduced into the reactor, the superficial gas velocity being controlled at 0.01m / s, and the activation being continued for 10 hours.

[0068] After the activation reaction was completed, the product was discharged at 600℃ under nitrogen protection, and finally a high-quality porous carbon with a specific surface area of ​​1640m² / g, a microporosity of 62%, and a yield of 26% was obtained.

[0069] Example 12: In this embodiment, the following is adopted: Figure 1 The apparatus shown uses coconut shell charcoal (a type of biochar) as the carbon raw material, which is obtained by crushing and sieving to obtain powder with a particle size of 5-8 μm. First, it is pretreated for 1 hour in the raw material preheating furnace of a nitrogen-protected fluidized bed reactor by heating to 500°C, and then transferred to the reactor for step-by-step activation.

[0070] In the step-by-step activation process, the first stage involves introducing a mixture of water vapor and nitrogen (volume ratio 6:4) into the reactor at 900℃, controlling the apparent gas velocity at 0.08 m / s, and continuing activation for 8 hours. The second stage involves adjusting the temperature to 1200℃ and introducing air into the reactor. Mix the gas with nitrogen (volume ratio 1:1), control the apparent gas velocity at 0.3 m / s, and activate for 3 hours.

[0071] After the activation reaction was completed, the product was discharged at 600℃ under nitrogen protection, and finally a high-quality porous carbon with a specific surface area of ​​1945m² / g, a microporosity of 68%, and a yield of 32% was obtained.

[0072] Comparative Example 1: The same coconut shell charcoal raw material as in Example 1 was used, and steam activation was carried out in a conventional rotary kiln. The activation temperature was controlled at 900°C, the activation time was 14 hours, the steam flow rate was the same as in Example 1, and the steam and nitrogen mixture (volume ratio 6:4) was controlled at an apparent gas velocity of 0.08 m / s.

[0073] After the activation reaction was completed, the product was discharged at 600°C under nitrogen protection. The resulting product had a specific surface area of ​​only 1350 m² / g and uneven pore size distribution, with a yield of 22%, which was significantly lower than that of the method of this invention.

[0074] Comparative Example 2: The petroleum coke feedstock of Example 2 was used, the only difference being that the process was carried out in a fixed-bed reactor. Under the same activation temperature (950℃) and activation reaction time (12 hours), due to the low mass transfer efficiency, the specific surface area of ​​the product was only 980m² / g, the mesopority was 55%, and the yield was 18%, which verified the significant advantage of fluidized bed in activation efficiency.

[0075] Comparative Example 3: The same coal tar pitch raw material as in Example 3 was used, except that the steam activation was performed in a rotary kiln. The activation temperature was controlled at 880°C, the activation reaction time was 10 hours, and the steam flow rate was equivalent. The specific surface area of the product was only 1200 m2 / g, the fiber morphology was severely damaged, the yield was 21%, and the anisotropy ratio of the electrical conductivity decreased to 1.5:1.

[0076] Comparative Example 4 The same phenolic resin carbon raw material as in Example 7 was used, except that the steam activation was performed in a fixed bed reactor under the same conditions (activation temperature 800°C, activation reaction time 10 hours). Due to mass transfer limitations, the specific surface area of the product was only 1500 m2 / g, the microporosity was 78%, and all performance indicators were significantly reduced.

[0077] As can be seen from the above examples, the average specific surface area of all porous carbons produced using the fluidized bed process is much higher than that of traditional processes, and the porous carbon produced using the multi-stage fluidized bed gradient activation has the largest specific surface area, indicating that the staged and multi-level activation process can maximize the specific surface area, and that the present application has an irreplaceable technical advantage in improving the pore structure of the material.

[0078] Thus far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings, but those skilled in the art will readily understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or substitutions to the relevant technical features without departing from the principles of the present application, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present application.

Claims

1. A method for activating porous carbon, characterized in that, include: Step S1: The carbon raw material is transported to the raw material preheating furnace for preheating in an inert atmosphere; Step S2: The preheated carbon raw material is transported to the reactor, and a reaction gas is introduced under preset activation conditions to carry out the activation reaction, thereby obtaining activated porous carbon. Step S3: The activated porous carbon is transported to the unloading tank under an inert atmosphere for cooling and then unloaded to obtain the porous carbon product. The activation conditions in step S2 include activation reaction temperature, activation reaction time and activation mode. The activation mode includes a one-step activation mode that uses a single activation gas for the reaction and a step-by-step activation mode that uses two activation gases alternately for the reaction. A fluidized bed reactor for porous carbon activation includes a feed tank, a raw material preheating furnace, a reactor, a heating unit, and a discharge tank. The reactor is equipped with a gas distributor, a stirring paddle, a cyclone separator, and / or a metal filter column. The reactor includes a straight section and an enlarged section.

2. The porous carbon activation method according to claim 1, characterized in that, In step S2, the reactant gas is a mixture of an activation gas and a carrier gas, wherein, Activating gases include water vapor, One or more of the following; the carrier gas includes one or more of nitrogen, argon, helium, and reaction tail gas; The apparent velocity of the total gas in the activation reaction is controlled to be 0.01 m / s to 0.3 m / s.

3. The porous carbon activation method according to claim 1, characterized in that, In step S2, the activating gas in the reaction gas accounts for 10% to 100% of the total gas composition of the carrier gas and the activating gas. When using the one-step activation mode, a single activation gas is used for the reaction, and the activation reaction time is 5h to 15h, wherein the single activation gas is water vapor or ; When using the stepped activation mode, two activation gases are used alternately for the activation reaction, and the activation reaction time for each activation gas is 3h to 10h.

4. The porous carbon activation method according to claim 1, characterized in that, In step S1, the preheating temperature of the carbon raw material is 300℃~700℃; the particle size of the carbon raw material is ≤200μm; and the specific surface area of ​​the carbon raw material is ≤800. ; The raw material preheating furnace is any one of a rotary kiln, fluidized bed, or moving bed; the heating method of the heating unit includes any one of electric heating, natural gas combustion heating, or reaction tail gas residual heat heating.

5. The porous carbon activation method according to claim 1, characterized in that step S3 includes: The activated porous carbon is transported to the unloading tank under an inert atmosphere without cooling or after cooling to 600℃±100℃. After cooling to below 50℃, it is unloaded to obtain the porous carbon product.

6. The porous carbon activation method according to claim 1, characterized in that, In step S2, the activation reaction temperature is 700℃~1200℃, and the activation reaction duration is 5h~15h.

7. The porous carbon activation method according to claim 1, characterized in that, The carbon raw material includes one or more of biochar, pitchblende, petroleum coke, and phenolic resin; the particle size of the carbon raw material is ≤200μm; and the specific surface area of ​​the carbon raw material is ≤800. .

8. The porous carbon activation method according to claim 3, characterized in that, In step S2, when using the stepped activation mode, two activation gases are used alternately for the activation reaction. First, water vapor is used as the activation gas for the activation reaction, and then... The activation reaction is carried out by the activation gas, and the activation reaction time of each activation gas is 5h to 10h.

9. The porous carbon activation method according to claim 1, characterized in that, There are multiple reactors, among which, The reactors are connected in series, and the carbon raw material is activated in each of the independently temperature-controlled reactors in sequence; Alternatively, the reactors can be connected in parallel, with the carbon raw material undergoing activation in each independently temperature-controlled reactor.

10. The porous carbon activation method according to claim 1 or 8, characterized in that, The reactor cavity includes a straight section and an enlarged section located at the top of the straight section; The reactor comprises multiple independently temperature-controlled reaction zones.

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