Method for preparing carbon black through thermal plasma fluidization, application and preparation device

Abstract

The invention relates to the technical field of carbon black preparation, in particular to a method for preparing carbon black through thermal plasma fluidization, application and a preparation device. The preparation method comprises the following steps: respectively preheating a reaction furnace and a fluidized bed reactor by adopting a direct-current arc plasma discharge mode; spraying atomized raw oil from an inlet of the reaction furnace, and carrying out primary pyrolytic reaction on the raw oil under the action of nitrogen plasma to form a primary carbon black aggregate; conveying the primary carbon black aggregate and the carbon dioxide plasma into a fluidized bed reactor for secondary activation reaction to generate a carbon black product; and cooling and carrying out gas-solid separation to obtain the high-structure carbon black. According to the invention, the plasma technology is creatively combined with the fluidized bed reactor, so that one-step preparation of the high-structure carbon black is realized.

Description

Technical Field

[0001] This invention relates to a method for preparing carbon black, specifically to a method, application, and preparation apparatus for preparing carbon black by thermal plasma fluidization. Background Technology

[0002] Carbon black is an important industrial raw material, widely used in rubber, plastics, inks, dyeing coatings, and new energy fields (such as conductive agents for lithium-ion batteries). The aggregate morphology and degree of aggregation of carbon black are key factors determining its performance. High-structure carbon black typically features small particle size, numerous branched chains in its aggregates, and complex morphology. When used to modify composite materials, it provides excellent reinforcing effects. For example, when mixed with polymers to form granules and added to textiles, its good dispersibility and excellent coloring strength can significantly improve dyeing uniformity, abrasion resistance, and antistatic properties. In the lithium battery industry, the high specific surface area and abundant branches of carbon black can promote the formation of a more developed three-dimensional conductive network in the slurry. Therefore, high-structure carbon black is in high demand in the chemical fiber industry, high-end conductive fields, and specialty rubbers.

[0003] Traditional carbon black production processes primarily utilize oil furnaces, which generate carbon black through the incomplete combustion and thermal pyrolysis of feedstock oil in high-temperature fuel gas. However, this method has several limitations. Firstly, the structure of carbon black is mainly controlled through reactor design, feedstock ratios, and process parameters. Traditional combustion methods have limited flexibility, resulting in unstable carbon black structures and significant product volatility, making it difficult to accurately and efficiently produce high-end varieties with specific complex structures. Secondly, the combustion process easily introduces impurities, and incomplete pyrolysis of the feedstock leads to a decrease in carbon black purity. Furthermore, the low conversion rate of feedstock during the reaction process not only wastes resources but also generates large amounts of tail gas containing CO, CO2, NOx, and sulfur oxides, which is detrimental to environmental protection and sustainable development.

[0004] Plasma technology, as a high-temperature, high-energy-density heat source, has been successfully applied in the field of materials synthesis. Plasma can provide temperatures far exceeding those of traditional combustion (reaching thousands or even tens of thousands of degrees Celsius). In a highly reactive plasma environment, the raw materials are rapidly and completely decomposed into atomic or ionic states, providing the reaction conditions for one-step synthesis of materials.

[0005] Although plasma technology is currently used to prepare carbon black, it primarily involves increasing the reaction temperature. Using plasma with a specific gaseous medium (such as air or nitrogen) as a single heat source, feedstock oil or gaseous hydrocarbons are directly injected into the arc zone or tail flame of the plasma torch, causing them to undergo high-temperature pyrolysis and nucleation growth to obtain carbon black products. Despite the extremely high plasma temperature, this single and concentrated high-temperature zone makes the reaction process too violent. Carbon black particles undergo pyrolysis on a millisecond scale, accompanied by rapid nucleation and growth, resulting in poor product dispersion and difficulty in precisely controlling the morphology of the aggregates towards a complex, highly branched ideal structure. Secondary modifications to the finished carbon black product, such as acid-base washing, mechanical grinding, surface coating, and coupling agent modification, suffer from unstable modification effects, significant reaction pollution, and complex and costly processes. Ultimately, the prepared carbon black products often fail to fully meet the performance requirements of high-end fields such as spinning and electrical conductivity in terms of specific surface area, structural density, and branching complexity. Summary of the Invention

[0006] The purpose of this invention is to provide a method, application, and preparation apparatus for preparing carbon black by thermal plasma fluidization, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: The first objective of this invention is to provide a method for preparing carbon black by thermal plasma fluidization, comprising the following steps: S1. The reactor and fluidized bed reactor are preheated by DC arc plasma discharge. The reactor is preheated by a nitrogen plasma generator to make the temperature of the decomposition and nucleation reaction zone 1400-2000℃. The fluidized bed reactor is preheated by a carbon dioxide plasma generator to make the temperature of the reaction zone 800-1000℃. S2. Atomized feed oil is injected into the inlet of the reactor. Under the action of nitrogen plasma, the feed oil undergoes a preliminary pyrolysis reaction to form primary carbon black aggregates. Then, the temperature is lowered to 750-850℃ to terminate the reaction. S3. The primary carbon black aggregates and carbon dioxide plasma are jointly transported to a fluidized bed reactor for a secondary activation reaction to generate carbon black products. S4. Cool to below 260℃ and perform gas-solid separation on the product to obtain high-structure carbon black and tail gas. A portion of the tail gas is recycled back to the fluidized bed reactor, and the remaining tail gas is sent to the boiler for combustion and heat generation to recover energy.

[0008] In a further embodiment, the nitrogen plasma generator consists of four groups, arranged symmetrically at equal angles along the circumferential direction of the reactor inlet end. The operating power of a single nitrogen plasma generator is 200-1000kW; the operating power of the carbon dioxide plasma generator is 100-500kW; and the temperature of both the nitrogen plasma generator and the carbon dioxide plasma generator is 3000-5000K.

[0009] In a further embodiment, the reactor is a horizontal reactor with an internal pressure maintained at a slightly positive pressure not exceeding 10 kPa; the outlet end of the horizontal reactor is vertically connected to a fluidized bed reactor, and a carbon dioxide plasma generator is installed at the connection between the horizontal reactor and the fluidized bed reactor and is directly connected to the fluidized bed reactor.

[0010] In a further embodiment, the internal pressure of the fluidized bed reactor is maintained at a slightly positive pressure not exceeding 30 kPa, the fluidizing gas velocity of the fluidized bed reactor is 0.2-1.0 m / s, and the reaction time is 20-40 min.

[0011] In a further embodiment, in step S2, the temperature of the raw oil is 130-200℃ and the moisture content is less than 0.5 wt%. The cooling process refers to introducing high-purity nitrogen gas at room temperature into the end of the reactor to lower the temperature.

[0012] In a further embodiment, in step S4, the cooling is performed by spraying atomized cooling water into the outlet section of the fluidized bed reactor; the gas-solid separation is performed by using a pulse backflushing collector.

[0013] The second objective of this invention is to provide a carbon black prepared by the above method, wherein the carbon black has a specific surface area >150 m². 2 / g, oil absorption value 120-400ml / 100g.

[0014] A third objective of this invention is to provide uses for the aforementioned carbon black, such as a colorant in spun fibers or a conductive additive in lithium batteries.

[0015] A fourth objective of this invention is to provide a preparation apparatus for implementing the above-described method, comprising a horizontal reactor and a fluidized bed reactor connected vertically. The inlet end of the horizontal reactor is equipped with a pressure atomizing nozzle communicating with the feed oil. Four nitrogen plasma generators are equally spaced on the horizontal reactor surrounding the pressure atomizing nozzle. The inlet end of the fluidized bed reactor is connected to a carbon dioxide plasma generator. The outlet of the fluidized bed reactor is connected to a pulse backflush collector, the outlet end of which is connected to a reflux port on the fluidized bed reactor to ensure a micro-positive pressure ≤30 kPa inside the fluidized bed reactor.

[0016] In a further embodiment, the interior of the horizontal reactor is divided into a pyrolysis nucleation reaction zone, a carbon particle growth zone, and a cooling zone from the inlet to the outlet. The cooling zone is provided with an inlet for connecting high-purity nitrogen. The outlet end of the fluidized bed reactor is connected to a cooling pipe, and the cooling pipe is provided with a cooling jacket on its outer periphery. A water inlet is opened on the cooling pipe, and atomized cooling water is sprayed into its inner cavity through the water inlet to cool the reaction products. The cooling jacket is connected to circulating cooling water to protect the pipeline equipment. The atomized cooling water is high-standard deionized water and does not affect the product performance.

[0017] Temperature sensors are installed in the pyrolysis nucleation reaction zone, carbon particle growth zone, cooling zone of the horizontal reactor, as well as the reaction section and cooling pipes of the fluidized bed reactor.

[0018] In a further embodiment, the fluidized bed reactor is provided with multiple distribution plates along the height direction inside, and the distribution plates are provided with a number of through holes, the opening area of ​​which accounts for 5-15% of the total area of ​​the distribution plates.

[0019] In this invention, the nitrogen plasma generator and carbon dioxide plasma generator utilize high-energy plasma generated by a high-temperature electric arc to rapidly transfer a large amount of heat energy to the reactor and fluidized bed reactor through radiation, convection, and heat conduction, achieving rapid temperature rise. The nitrogen plasma generator and carbon dioxide plasma generator operate at temperatures of 3000-5000K, thereby providing a thermodynamic equilibrium temperature field and ensuring a uniform and stable temperature in the reaction system.

[0020] This invention involves injecting atomized feedstock oil into a high-temperature horizontal furnace reactor. Within a core high-temperature zone of 3000-5000K constructed by plasma, extremely rapid thermal decomposition and chemical reactions occur, generating polycyclic aromatic hydrocarbons (PAHs) / carbon-containing free radicals. These PAHs / carbon-containing free radicals continuously form carbon nuclei in the horizontal furnace at 1400-2000℃ during intense gas-solid contact and particle collisions. These carbon nuclei then coalesce and grow, forming carbon black aggregates with preliminary branching structures. Nitrogen plasma provides the primary heat source, ensuring the necessary heat input for feedstock oil decomposition. Furthermore, the highly reactive N2 in the plasma atmosphere facilitates the formation of carbon black with specific surface chemical properties. Subsequently, the carbon black aggregates and carbon dioxide plasma are co-transported to a fluidized bed reactor for secondary activation, generating carbon black products. This combined reaction mode of "horizontal furnace pyrolysis + fluidized bed secondary activation" achieves directional control of the carbon black structure.

[0021] In this invention, a multi-layered distribution plate is installed inside the fluidized bed reactor, with an opening ratio of 5%-15%, thereby ensuring sufficient contact between the carbon black aggregates and the carbon dioxide plasma. The carbon black is fluidized in a highly active plasma environment. The unique environment of the fluidized bed promotes uniform heating and effective collision of the particles. Simultaneously, the carbon dioxide plasma provides a highly active oxidizing atmosphere, performing in-situ micro-etching on the carbon black surface. This achieves etching of the carbon black particle surface and secondary structural growth, forming a final high-structure carbon black product with a well-developed structure and uniform morphology.

[0022] Carbon dioxide plasma serves as the main heat source and reaction medium in the fluidized bed reactor. As a fluidizing gas, it can regulate the oxidizing atmosphere in the reaction zone, improve the dispersion of carbon black, and keep the fine carbon nuclei in the reactor in an active fluidized state, forming a high-temperature fluidized reaction zone.

[0023] This invention utilizes the synergistic effect of nitrogen plasma and carbon dioxide plasma, and by adjusting the power of nitrogen or carbon dioxide plasma, the feed rate and atomization degree of the raw oil, the fluidizing gas velocity of the fluidized bed reactor, and the temperature field distribution within the reactor, it achieves precise control over the size, morphology, pore structure, and specific surface area of ​​carbon black aggregates, thereby enabling the targeted production of carbon black products.

[0024] In this invention, the working gas of the plasma generator is nitrogen and carbon dioxide, wherein the purity of nitrogen is not less than 99.99% and the purity of carbon dioxide is not less than 99.9%.

[0025] Therefore, this invention innovatively combines plasma technology with a fluidized bed reactor to achieve one-step preparation of high-structure carbon black. Plasma provides extreme reaction conditions, ensuring complete pyrolysis of the feedstock oil and providing a high concentration of active carbon source for carbon black generation; the fluidized bed reactor provides a unique "dynamic" environment for the growth of carbon black particles, where the intense movement, collision, agglomeration, and secondary modification of the particles are conducive to the formation of high-structure carbon black with many branches, well-developed chain structures, and a large specific surface area.

[0026] This invention uses thermal plasma as the core heat source, which boasts high energy density and rapid heating rate, and eliminates the need for fuel combustion, fundamentally preventing the generation and emission of large amounts of pollutants such as NOx and SOx. The reaction process is clean and perfectly aligns with the dual-carbon policy. The final separated exhaust gas is rich in combustible components, allowing for recycling and further reducing energy consumption.

[0027] The high-structure carbon black prepared by this invention has a well-developed three-dimensional network structure. When used as a colorant carbon black in spinning fibers, it can effectively improve the coloring strength and mechanical properties of the fibers. When used as a conductive carbon black in lithium-ion batteries, it can form excellent conductive pathways in electrode materials, exhibiting extremely high discharge capacity and cycle retention rate. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the preparation device of the present invention; Figure 2 Transmission electron microscopy image of carbon black particles prepared in Example 1; Figure 3 The primary particle size distribution diagram is shown for the carbon black prepared in Example 1. Figure 4 The DLS test fluid dynamics size distribution diagram of the carbon black prepared in Example 1; Figure 5 Electron micrograph of the spun fiber product prepared in Application Example 1; Figure 6 Transmission electron microscopy image of the carbon black particles prepared in Example 2; Figure 7 This is a primary particle size distribution diagram of the carbon black prepared in Example 2; Figure 8 The DLS test fluid dynamics size distribution diagram of the carbon black prepared in Example 2; Figure 9 The discharge efficiency diagram of the lithium iron phosphate battery in Application Example 2; Figure 10 The cycle rate diagram is for the lithium iron phosphate battery in Application Example 2.

[0029] Figure 1 In the middle: 1-pressure atomizing nozzle, 2-nitrogen plasma generator, 3-horizontal reactor, 31-air inlet, 4-temperature sensor, 5-carbon dioxide plasma generator, 6-fluidized bed reactor, 61-reflux port, 62-water inlet, 63-cooling pipe, 7-pulse backflush collector. Detailed Implementation

[0030] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0031] Example 1: This embodiment provides a method for preparing high-structure carbon black by thermal plasma fluidization, and the specific steps are as follows: S1. The horizontal reactor and the fluidized bed reactor are preheated by DC arc plasma discharge. The horizontal reactor is preheated by four nitrogen plasma generators to raise the temperature to 1700℃ in the pyrolysis nucleation reaction zone. The fluidized bed reactor is preheated by a carbon dioxide plasma generator to raise the temperature of its reaction zone to 1000℃. S2. Preheat the coal tar to 150℃ and then purify and dry it to ensure that the moisture content is ≤0.3wt%. S3. The solution is injected into the horizontal reactor through a 0.5 MPa pressure atomizing nozzle. S4. Adjust the power of the four nitrogen plasma generators to 250kW each, with a total power of 1MW, to generate thermal plasma at a temperature of 3000K for high-temperature pyrolysis of coal tar. Control the temperatures T1 and T2 of the cracking nucleation reaction zone and carbon particle growth zone of the horizontal reactor to 1700℃ and 1400℃ respectively. Cool the cooling zone of the horizontal reactor with high-purity nitrogen at room temperature to make its temperature T3 750℃. S5. Adjust the power of the carbon dioxide plasma generator to 400kW, maintain the internal temperature T4 of the fluidized bed reactor at 1000℃, the fluidizing gas velocity at 0.5m / s, and the reaction time at 30min.

[0032] In a fluidized bed reactor, carbon dioxide plasma has a certain oxidizing property. It performs in-situ micro-etching on the growing carbon black aggregates in the fluidized bed, increasing the surface active sites and improving their dispersibility in the polymer matrix without significantly damaging the main structure.

[0033] S6. The high-structure carbon black particles generated in the reaction leave the fluidized bed reactor along with the tail gas. After being sprayed with atomized quench water at the cooling pipe, the temperature T5 at the cooling pipe is reduced to 250℃. The mixture then enters the pulse backflushing collector for gas-solid separation. The carbon black is captured by the filter bag and periodically collected by pulse backflushing. A portion of the tail gas (mainly containing H2, N2, and a small amount of CO) is recycled back into the fluidized bed reactor, maintaining its internal pressure at a slightly positive pressure ≤30 kPa.

[0034] Detection Example 1: The carbon black prepared in Example 1 was subjected to the following tests: like Figure 2 The image shown is a transmission electron microscope (TEM) image of the carbon black particles prepared in Example 1. As can be seen from the image, the carbon black particles prepared in Example 1 are uniformly dispersed and show no obvious agglomeration.

[0035] Figure 3 and Figure 4 The figures show the primary particle size distribution and the hydrodynamic size (agglomeration size) of the carbon black prepared in Example 1, as well as the hydrodynamic size measured by DLS. The figures show that the particle size distribution is narrow and the polydispersity index (PDI=0.018) is small, which indicates that the particle size in the system tends to be uniform. This parameter provides a good foundation for its application in the spinning field.

[0036] The relevant properties of the carbon black prepared in Example 1 were tested, as shown in Table 1 below.

[0037] Table 1

[0038] As can be seen from Table 1, the specific surface area of ​​the carbon black prepared in this embodiment is 160 m². 2 / g, oil absorption value 113ml / 100g. Its excellent performance makes it suitable as a colorant in spun fibers.

[0039] Application Example 1: Masterbatch was prepared using carbon black prepared in Example 1 as an additive.

[0040] The carrier resin used was low-density polyethylene (LLDPE) (55%wt) with a melt flow rate (MFR) of 20-30 g / 10 min, the same type as the spinning chips, to ensure compatibility and matching with the spinning temperature. The dispersion system used oxidized polyethylene wax, combined with ethylene-acrylic acid copolymer metal salt (total 5%wt); the functional additives included antioxidant (0.2%) + DLTP (0.3%) to prevent high-temperature degradation, and silane coupling agent KH550 (0.5%) to improve the bonding force between carbon black and resin; the balance was the carbon black prepared in Example 1.

[0041] After mixing the above raw materials, the color masterbatch raw materials are prepared by melting and extruding using a twin-screw extruder.

[0042] Polyethylene (PE) fibers were prepared by adding masterbatch raw materials at a total addition rate of 3% wt to dried LLDPE spinning chips, followed by mixing, melting, extrusion granulation, and finally processing. Electron micrographs of the prepared polyethylene fibers are shown below. Figure 5 As shown.

[0043] Simultaneously, using Orion's spinning carbon black product AS11, polyethylene fibers were prepared according to the same method described above, serving as Comparative Example 1. The relevant properties of the polyethylene fibers prepared in Application Example 1 and Comparative Example 1 were then tested, as detailed in Tables 2 and 3.

[0044] Table 2

[0045] Table 3

[0046] As can be seen from the table above, adding the carbon black prepared in Example 1 as a coloring additive to polyethylene fibers can meet the requirements of spinning-grade special carbon black, and it is superior to commercial products in some aspects.

[0047] Example 2: Based on Example 1, in order to control the characteristics of primary carbon black particles and the surface properties after fluidization reaction, the nitrogen plasma generator and the carbon dioxide plasma generator were adjusted.

[0048] The specific preparation method is the same as in Example 1, except that in step S2, the power of the four nitrogen plasma generators is adjusted to 500kW, so the total power is 2MW and the thermal plasma temperature is 4000K; the temperature T1 of the cracking and nucleation reaction zone of the horizontal reactor is controlled to be 2000℃ and the temperature T2 of the carbon particle growth zone is controlled to be 1500℃; the cooling zone of the horizontal reactor is cooled by high-purity nitrogen to make its temperature T3 800℃.

[0049] In step S3, the gas flow rate of the carbon dioxide plasma generator is increased, its power is adjusted to 200kW, the fluidized bed reactor temperature T4 is maintained at 800℃, the fluidizing gas velocity is 1.0m / s, and the reaction time is 20min.

[0050] Detection Example 2: The carbon black prepared in Example 2 was subjected to the following tests: The carbon black prepared in Example 2 has the following transmission electron microscopy image: Figure 6 As shown in the figure, the carbon black particles prepared in Example 1 are uniformly dispersed and have no obvious agglomeration structure.

[0051] Figure 7 and Figure 8 The figures show the primary particle size distribution and hydrodynamic size (agglomeration size) of the carbon black prepared in Example 2, as measured by DLS. It can be seen that the carbon black prepared in this example has a smaller average particle size (19.47 ± 3.85 nm).

[0052] The relevant physical properties of the carbon black prepared in Example 2 are shown in Table 4 below: Table 4

[0053] As can be seen from Table 4, the carbon black prepared in Example 2 has a BET specific surface area of ​​240 m² / g and an oil absorption value of 290 ml / 100g.

[0054] The carbon black prepared in this embodiment has a small particle size. Overly small particles may affect its dispersibility in spinning products, but when used in lithium battery cathode materials, it can form a good conductive network with active materials with poor conductivity, significantly improving its conductivity.

[0055] Application Example 2: The carbon black sample prepared in Example 2 was used as a conductive additive to prepare the positive electrode of a lithium iron phosphate button battery. The specific steps are as follows: Lithium iron phosphate, carbon black, and PVDF binder were mixed in a ratio of 92:3:5 to obtain a slurry. The slurry was then coated with a width of 150 μm and dried. The thickness of the electrode sheet was controlled to be 50 ± 5 μm after rolling to obtain the positive electrode sheet.

[0056] A button cell battery is manufactured by assembling a positive electrode shell, a positive electrode sheet, a separator, a lithium sheet, and a negative electrode shell, and filling the interior with electrolyte.

[0057] For comparison, button cells were prepared using the same method described above with commonly available conductive carbon black SP (SP produced by TIMCAL) as Comparative Example 2.

[0058] The button batteries prepared for use case 2 and comparative example 2 were subjected to specific capacity, first efficiency and cycle charge-discharge tests. Figure 9 and Figure 10 The figure shows the battery's first-cycle discharge efficiency and cycle rate performance. As can be seen from the figure, at 0.5C, the battery prepared in Example 2 has a first-cycle discharge capacity of 154.3 mAh / g, a first-cycle charge-discharge efficiency of 94%, and a cycle retention rate of 99.07% after 100 cycles, demonstrating excellent discharge performance and cycle retention rate. This is significantly better than the performance of Comparative Example 2.

[0059] Example 3: This embodiment provides a method for preparing high-structure carbon black by thermal plasma fluidization, and the specific steps are as follows: S1. A DC arc plasma discharge method is used to preheat the horizontal reactor and the fluidized bed reactor respectively. The horizontal reactor is preheated with four nitrogen plasma generators to make its decomposition and nucleation reaction zone temperature 1400℃; the fluidized bed reactor is preheated with a carbon dioxide plasma generator to make its reaction zone temperature 900℃. S2. Preheat the coal tar to 200℃ and then purify and dry it to ensure that the moisture content is ≤0.5wt%. S3. The solution is injected into the horizontal reactor through a 1 MPa pressure atomizing nozzle. S4. Adjust the power of the four nitrogen plasma generators to 1000kW, with a total power of 4MW, to generate thermal plasma at a temperature of 5000K for high-temperature pyrolysis of coal tar. Control the temperatures T1 and T2 of the cracking nucleation reaction zone and carbon particle growth zone of the horizontal reactor to 1400℃ and 1300℃ respectively. Cool the cooling zone of the horizontal reactor with high-purity nitrogen to make its temperature T3 850℃. S5. Adjust the power of the carbon dioxide plasma generator to 100kW, maintain the internal temperature T4 of the fluidized bed reactor at 900℃, the fluidizing gas velocity at 0.8m / s, and the reaction time at 25min.

[0060] In a fluidized bed reactor, carbon dioxide plasma has a certain oxidizing property. It performs in-situ micro-etching on the growing carbon black aggregates in the fluidized bed, increasing the surface active sites and improving their dispersibility in the polymer matrix without significantly damaging the main structure.

[0061] S6. The high-structure carbon black particles generated in the reaction leave the fluidized bed reactor along with the tail gas. After being sprayed with atomized quench water at the cooling pipe, the temperature T5 at the cooling pipe is reduced to 250℃. The mixture then enters the pulse backflushing collector for gas-solid separation. The carbon black is captured by the filter bag and periodically collected by pulse backflushing. A portion of the tail gas (mainly containing H2, N2, and a small amount of CO) is recycled back into the fluidized bed reactor, maintaining its internal pressure at a slightly positive pressure ≤30 kPa.

[0062] The relevant physical properties of the carbon black prepared in Example 3 are shown in Table 5 below: Table 5

[0063] Comparative Example 3: Same as Example 1, except that the power of the nitrogen plasma reactor is adjusted to 150kW per group, with a total power of 600kW, so that the temperature of the pyrolysis nucleation reaction zone of the reactor is 1200℃.

[0064] Comparative Example 4: Same as Example 1, except that the reaction zone temperature of the fluidized bed reactor is 600℃ (same as above, not in the range of 800-1000℃). Comparative Example 5: Same as Example 1, except that the plasma working gas in both the reactor and the fluidized bed reactor is nitrogen.

[0065] The properties of the carbon black products prepared in Comparative Examples 3-5 were tested, as shown in Table 6 below: Table 6

[0066] As can be seen from the table above, compared with Example 1 of this application, in Comparative Example 3, due to the lower temperature in the pyrolysis nucleation reaction zone of the reactor, the feed oil could not be guaranteed to be fully pyrolyzed, resulting in a significant decrease in the specific surface area and oil absorption value of the carbon black product. Furthermore, the toluene transmittance test (GB / T 3780.15-2016) of the sample in this comparative example was only 30%, which also proves that the carbon black did not react completely, and nucleation and growth were inhibited. In Comparative Example 4, the reduced temperature in the reaction zone of the fluidized bed reactor led to a significant decrease in activation efficiency, resulting in reduced etching effect on the carbon black surface, lower specific surface area, and weaker coloring intensity. In Comparative Example 5, since nitrogen was used exclusively as the plasma working gas, the entire reactor was in a reducing atmosphere. The original carbon dioxide gas could not effectively oxidize, etch, and modify the carbon black particles in the fluidized bed, leading to a decrease in specific surface area and a substantial increase in coking residue, directly impacting downstream applications.

[0067] Example 4: like Figure 1 As shown, this embodiment provides a preparation apparatus for implementing the above method, which includes a horizontal reactor 3 and a fluidized bed reactor 6 connected vertically. A pressure atomizing nozzle 1 connected to the feed oil is installed at the inlet end of the horizontal reactor 3. The pressure atomizing nozzle 1 sprays the feed oil into the interior of the horizontal reactor 3, maintaining the internal pressure at a slightly positive pressure not exceeding 10 kPa. Four nitrogen plasma generators 2 are installed at equal intervals on the horizontal reactor 3 located on the outer periphery of the pressure atomizing nozzle 1. The high-energy plasma generated by the high-temperature electric arc rapidly transfers a large amount of heat energy to the horizontal reactor 3 through radiation, convection and heat conduction to heat it. Under high-temperature conditions, the feed oil and the plasma undergo extremely rapid thermal decomposition and chemical reaction to generate carbon black aggregates with a preliminary branched structure.

[0068] The inlet of the fluidized bed reactor 6 is connected to a carbon dioxide plasma generator 5. High-energy plasma generated by a high-temperature electric arc is used to rapidly transfer a large amount of heat energy to the fluidized bed reactor 6 through radiation, convection, and heat conduction. The carbon black aggregates and carbon dioxide plasma are jointly transported to the fluidized bed reactor for a secondary activation reaction, generating carbon black products. The outlet of the fluidized bed reactor 6 is connected to a pulse backflush collector 7, which separates the generated carbon black products from the exhaust gas. A portion of the exhaust gas is connected to the return port 61 on the fluidized bed reactor 6 via the outlet of the pulse backflush collector 7 to ensure a micro-positive pressure ≤30 kPa inside the fluidized bed reactor.

[0069] In a further embodiment, the interior of the horizontal reactor 3 is divided into a pre-reaction zone, a middle reaction zone, and a cooling zone from the inlet end to the outlet end. The cooling zone is provided with an inlet 31 for connecting high-purity nitrogen gas; that is, the cooling zone of the horizontal reactor is cooled by high-purity nitrogen gas, thereby cooling the generated carbon black aggregates.

[0070] The outlet end of the fluidized bed reactor 6 is connected to a cooling pipe 63, which is equipped with a cooling jacket. A water inlet 62 is provided on the cooling pipe 63, through which atomized cooling water is sprayed into its inner cavity to cool the reaction products. Circulating cooling water is connected to the cooling jacket to protect the pipeline equipment. This process cools the carbon black product and tail gas entering the cooling pipe to 250°C before they enter the pulse backflushing collector 7 for gas-solid separation.

[0071] Temperature sensors 4 are installed in the front reaction zone, middle reaction zone, and cooling zone of the horizontal reactor 3, as well as in the reaction section and cooling pipes of the fluidized bed reactor 6. These sensors are used to precisely control the temperature of each reaction zone in order to control the generation of carbon black.

[0072] In a further embodiment, the fluidized bed reactor 6 has multiple distribution plates arranged along its height. Each distribution plate has several through-holes, with the opening area of ​​the through-holes accounting for 5-15% of the total area of ​​the distribution plate. This ensures sufficient contact between the carbon black aggregates and the carbon dioxide plasma, meaning the carbon black is fluidized in a highly active plasma environment. The unique environment of the fluidized bed promotes uniform heating and effective collision of the particles. Simultaneously, the carbon dioxide plasma provides a highly active oxidizing atmosphere, performing in-situ micro-etching on the carbon black surface, achieving etching and secondary structural growth of the carbon black particles, resulting in a final high-structure carbon black product with a well-developed structure and uniform morphology.

[0073] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to the embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing carbon black by thermal plasma fluidization, characterized in that, Includes the following steps: S1. The reactor and fluidized bed reactor are preheated by DC arc plasma discharge. The reactor is preheated by a nitrogen plasma generator to make the temperature of the decomposition and nucleation reaction zone 1400-2000℃. The fluidized bed reactor is preheated by a carbon dioxide plasma generator to make the temperature of the reaction zone 800-1000℃. S2. Atomized feed oil is injected into the reactor inlet. Under the action of nitrogen plasma, the feed oil undergoes a preliminary pyrolysis reaction to form primary carbon black aggregates. Then, the temperature is lowered to 750-850℃ to terminate the nucleation reaction of the carbon black. S3. The primary carbon black aggregates and carbon dioxide plasma are jointly transported to a fluidized bed reactor for a secondary activation reaction to generate carbon black products. S4. Cool to below 260℃ and perform gas-solid separation on the product to obtain high-structure carbon black and tail gas. A portion of the tail gas is recycled back to the fluidized bed reactor, and the remaining tail gas is sent to the boiler for combustion and heat generation to recover energy.

2. The method according to claim 1, characterized in that, The nitrogen plasma generator consists of four groups, which are equally spaced around the inlet end of the reactor. The operating power of a single nitrogen plasma generator is 200-1000kW; the operating power of a carbon dioxide plasma generator is 100-500kW; and the temperature of both the nitrogen plasma generator and the carbon dioxide plasma generator is 3000-5000K.

3. The method according to claim 1, characterized in that, The reactor is a horizontal reactor, and its internal pressure is maintained at a slightly positive pressure not exceeding 10 kPa. The internal pressure of the fluidized bed reactor is maintained at a slightly positive pressure not exceeding 30 kPa, the fluidizing gas velocity of the fluidized bed reactor is 0.2-1.0 m / s, and the reaction time is 20-40 min.

4. The method according to claim 1, characterized in that, In step S2, the temperature of the raw oil is 130-200℃ and the moisture content is less than 0.5 wt%. The cooling process refers to introducing high-purity nitrogen gas into the end of the reactor to lower the temperature.

5. The method according to claim 1, characterized in that, In step S4, the cooling is performed by spraying atomized cooling water into the outlet section of the fluidized bed reactor; the gas-solid separation is performed by using a pulse backflushing collector.

6. A carbon black prepared by the method according to any one of claims 1-5, characterized in that, The specific surface area of ​​the carbon black is >150m². 2 / g, oil absorption value 120-400ml / 100g.

7. The use of carbon black as described in claim 6, characterized in that, It is used as a colorant in spun fibers or as a conductive additive in lithium batteries.

8. An apparatus for implementing the method according to any one of claims 1-5, characterized in that, The system includes a horizontal reactor (3) and a fluidized bed reactor (6) connected vertically. The inlet end of the horizontal reactor (3) is equipped with a pressure atomizing nozzle (1) that communicates with the feed oil. Four nitrogen plasma generators (2) are installed at equal intervals on the horizontal reactor (3) located on the outer periphery of the pressure atomizing nozzle (1). The inlet end of the fluidized bed reactor (6) is connected to a carbon dioxide plasma generator (5). The outlet of the fluidized bed reactor (6) is connected to a pulse backflush collector (7). The outlet end of the pulse backflush collector (7) is connected to the return port (61) on the fluidized bed reactor (6) to ensure that the micro-positive pressure inside the fluidized bed reactor is ≤30 kPa.

9. The preparation apparatus according to claim 8, characterized in that, The interior of the horizontal reactor (3) is divided into a cracking nucleation reaction zone, a carbon particle growth zone and a cooling zone from the inlet end to the outlet end. The cooling zone is provided with an inlet (31) for connecting high-purity nitrogen. The outlet end of the fluidized bed reactor (6) is connected to a cooling pipe (63), the outer periphery of the cooling pipe is provided with a cooling jacket, and a water inlet (62) is opened on the cooling pipe. The reaction products are cooled by spraying atomized cooling water into its inner cavity through the water inlet (62). Circulating cooling water is connected in the cooling jacket. Temperature sensors (4) are installed in the pyrolysis nucleation reaction zone, carbon particle growth zone, cooling zone of the horizontal reactor (3), as well as the reaction section and cooling pipe of the fluidized bed reactor (6).

10. The preparation apparatus according to claim 8, characterized in that, The fluidized bed reactor (6) has multiple distribution plates arranged along the height direction inside. The distribution plates have several through holes, and the opening area of ​​the through holes accounts for 5-15% of the total area of ​​the distribution plates.

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