Method and device for preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma

Abstract

The present application relates to the field of nanomaterial preparation and plasma chemical engineering, and particularly relates to a method and device for preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma. The method comprises: introducing nitrogen into a cracking zone of a reaction furnace to form high-temperature nitrogen plasma by ionization via a plasma generator; injecting low-carbon hydrocarbon raw materials into the high-temperature nitrogen plasma to perform a cracking reaction under oxygen-free conditions at a temperature of 1400-1800 DEG C, to generate a mixed gas stream comprising carbon, nitrogen and hydrogen plasma; introducing the mixed gas stream into a reaction zone to complete carbon particle growth at 1000-1600 DEG C, and to generate ammonia by combining nitrogen and hydrogen; and subsequently rapidly cooling, cooling down and gas-solid separating the gas stream to obtain carbon black products. The present application uses nitrogen as a working gas, and has the advantages of simple process, low energy consumption, small electrode loss, no carbon deposition problem, and the ability to efficiently prepare high-purity, high-structure conductive carbon black, while simultaneously producing ammonia gas, which is safe and environmentally friendly, and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the fields of nanomaterial preparation and plasma chemical technology, and in particular to a method and apparatus for preparing carbon black by cracking low-carbon hydrocarbons (hydrocarbons containing ≤3 carbons) using high-temperature nitrogen plasma. Background Technology

[0002] Carbon black, especially high-performance conductive carbon black, is widely used in lithium battery conductive agents, carbon-coated copper foil, specialty coatings, inks, printed circuit boards, and other fields. Existing technologies for preparing carbon black mainly include traditional furnace black processing and its derivative low-carbon and clean production methods, carbon dioxide utilization technologies, and emerging plasma methods.

[0003] The traditional furnace black process is currently the mainstream in the industry, producing carbon black by controlling the incomplete combustion or pyrolysis of hydrocarbons. This process uses gaseous or liquid hydrocarbons (such as natural gas and light oil) as raw materials, partially burning and heating them in a reactor, while the remaining portion is cracked to produce carbon black. Its carbon conversion rate can reach over 60%, and energy efficiency is improved and unit energy consumption is reduced through large-scale reactors and plant-wide optimization, representing a low-carbon development direction. While the traditional furnace black process is mature, it suffers from high energy consumption, easy generation of pollutants such as sulfur dioxide and nitrogen oxides, and limited precision in product performance control.

[0004] Carbon dioxide utilization technology is an emerging green pathway that uses CO2 as a raw material to convert it into carbon black through coal oxidation or photocatalysis, thereby turning greenhouse gases into resources, reducing dependence on fossil fuels, and achieving carbon emission reduction. However, it is still in the research and development stage and faces challenges in reaction efficiency and cost control.

[0005] The plasma pyrolysis technology for producing carbon black from low-carbon hydrocarbons is based on the principle of plasma pyrolysis. It utilizes a plasma region (typically generated by an electric arc, high-frequency discharge, or microwave ionization) to instantaneously break the molecular bonds of low-carbon hydrocarbon feedstocks such as methane and ethane, generating carbon black and hydrogen as a byproduct. This method produces carbon black with a high specific surface area and a carbon conversion rate of approximately 90%, and the byproduct hydrogen emits no greenhouse gases, making it suitable for high-end applications such as conductive agents for lithium batteries.

[0006] Plasma technology, as an emerging carbon black preparation method, utilizes high-energy plasma to pyrolyze low-carbon hydrocarbons (such as methane and acetylene), offering advantages such as high carbon conversion rate, pure products, and no combustion pollutants. Based on plasma temperature, it can be divided into low-temperature (cold) plasma processes and high-temperature (hot) plasma processes. However, current plasma technologies still face many challenges: (1) The defects of the existing low-temperature (cold) plasma process are: the low-temperature plasma obtained by high-voltage, low-current AC arc discharge has the advantages of easy breakdown of carrier gas and low macroscopic temperature, but the conversion rate is not high and the carbon deposition phenomenon is serious, which will affect the purity of the product and the stability of the process; in addition, the process faces the problems of high cost and high energy consumption in the industrialization process, which limits its large-scale application.

[0007] (2) The defects of the existing high temperature (thermal) plasma process are: high temperature operation leads to heavy equipment load, and the introduction of gases such as methane or carbon dioxide makes the electrode of the plasma generator in an oxidizing or reducing environment, which leads to prominent electrode wear, shortens the service life of the electrode, and increases maintenance costs and operational complexity; at the same time, the high temperature environment has high requirements for production equipment, which may trigger side reactions and affect product consistency.

[0008] (3) Both low-temperature and high-temperature processes have insufficient technological maturity and have not yet been applied on a large scale in industrial applications; the reaction area is small, and the reactor design and process control still need to be optimized in order to improve energy efficiency and product yield.

[0009] (4) Although the plasma generated by using inert gases such as argon and helium as auxiliary gases has good inertness, it is expensive; using oxygen-containing ions such as air will introduce a large amount of oxygen, resulting in product oxidation and impurity, and the reaction temperature in the reaction zone is high (high energy consumption); when working in an oxidizing or reducing environment, the electrode wear is high.

[0010] Therefore, developing a new carbon black preparation technology that is simple in process, low in energy consumption, long in electrode life, produces excellent and adjustable product performance, is safe and environmentally friendly, and is easy to industrialize has important industrial value. Summary of the Invention

[0011] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a method and apparatus for preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma. This invention utilizes high-temperature nitrogen plasma to crack low-carbon hydrocarbons in a high-temperature, oxygen-free environment. Nitrogen plasma, as the reactant gas, contacts low-carbon hydrocarbon gases, instantly breaking their molecular bonds to generate carbon black. This method offers numerous advantages, including high purity, low impurities, small particle size, strong conductivity, large specific surface area, and good carbon black structure. Furthermore, the product exhibits stable properties, a simple process, low energy consumption, low electrode loss, and no carbon buildup, making it suitable for high-end applications.

[0012] The technical solution adopted by this invention to solve its technical problem is: A method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma specifically includes the following steps: Step S1, System Gas Replacement: Nitrogen gas is introduced into the reactor to replace the air, so that an oxygen-free environment is formed in the entire production system, providing a safe working environment; Step S2, Plasma generator start-up: Nitrogen gas is introduced into the plasma generator to ionize and form high-temperature nitrogen plasma, which is then introduced into the pyrolysis zone of the reactor to maintain the temperature of the pyrolysis zone at 1400-1800°C. Step S3, Raw material pyrolysis: Low-carbon hydrocarbon raw materials with ≤3 carbon atoms are injected into the high-temperature nitrogen plasma in the pyrolysis zone of the reactor. The pyrolysis reaction is carried out under the conditions of 1 to 1.5 atmospheres and residence time of 0.01 to 1 second. The low-carbon hydrocarbon raw materials are pyrolyzed to generate a mixed gas flow containing nitrogen, carbon and hydrogen active particles. Step S4, Reaction and Nucleation: The mixed gas flow is introduced into the reaction zone of the reactor. Under the conditions of 1000-1600℃, 1-1.4 atmospheres, and residence time of 0.05-5 seconds, the nitrogen, carbon, and hydrogen active particles in the mixed gas flow react rapidly in the reaction zone to generate carbon black particles and ammonia, forming a high-temperature gas-solid mixed gas flow. Step S5, Rapid Cooling to Terminate the Reaction: The high-temperature gas-solid mixed gas flow from the reaction zone of the reactor is introduced into the rapid cooling zone of the reactor and rapidly cooled to below 800°C within 3 seconds to terminate the reaction; Step S6, Cooling and Collection: The rapidly cooled gas-solid mixture is further cooled, followed by gas-solid separation, and the carbon black product is collected. Step S7, exhaust gas treatment: The exhaust gas after carbon black separation is recycled and reused.

[0013] The preparation method of this invention is carried out entirely in an oxygen-free environment, eliminating the risk of explosion from the source and avoiding the release of CO, CO2, and NO. X This method avoids the generation of pollutants such as hydrogen. High-temperature nitrogen plasma not only provides pyrolysis energy, but its nitrogen-active particles can also react with the hydrogen-active particles produced by pyrolysis to generate ammonia, rather than hydrogen gas. This solves the safety challenges of storing and transporting the byproduct hydrogen and transforms the byproduct into valuable chemicals. This preparation method provides a systematic solution to the two core defects of existing plasma methods: high electrode wear and carbon deposition.

[0014] Furthermore, in step S3, the low-carbon hydrocarbon feedstock is one or more of methane, ethane, ethylene, acetylene, propane, propylene, or propyne. The method of this invention is not only applicable to the simplest methane, but also to low-carbon hydrocarbons with different structures such as acetylene, ethylene, and propylene, demonstrating the wide applicability and flexibility of the process, which can be flexibly adjusted according to the market price and supply of raw materials.

[0015] Furthermore, in steps S2 and S3, the atomic ratio of nitrogen gas introduced to hydrogen atoms in the low-carbon hydrocarbon feedstock is N:H = (0.25–0.5):1. If the ratio is too low, insufficient nitrogen and inadequate hydrogen bonding may lead to an increase in byproduct hydrogen gas, reducing safety and potentially affecting the carbon black structure and conversion rate. If the ratio is too high, excess nitrogen will result in an increase in unreacted nitrogen and byproduct hydrazine, potentially reducing energy efficiency and the yield of liquid ammonia. This range ensures efficient nitrogen-hydrogen ammonia synthesis while optimizing carbon black yield and performance.

[0016] Furthermore, in step S5, rapid cooling is performed using one or more of the following methods: pure water spraying, introducing cold nitrogen gas, introducing cold exhaust gas, and heat exchange. Rapid cooling can instantly "freeze" the nucleation and growth state of carbon black particles, preventing them from over-growing, sintering, or undergoing unnecessary side reactions (such as generating acetylene, HCN, etc.). This is a key step in obtaining high-quality carbon black with a narrow particle size distribution and uniform structure.

[0017] Furthermore, in step S6, the gas-solid separation employs one or more of the following methods: cyclone sedimentation, bag filtration, electrostatic adsorption, water spraying, and metal baffle deposition.

[0018] Furthermore, in step S7, the exhaust gas treatment includes: first, purifying and concentrating the ammonia in the exhaust gas obtained in step S6 to obtain liquid ammonia; and then using the remaining exhaust gas as fuel for combustion power generation.

[0019] The main byproduct, ammonia, is purified into commercial liquid ammonia, directly generating economic benefits and turning "waste" into treasure. The remaining combustible exhaust gas is used for combustion power generation, recovering energy and feeding it back into the production system, significantly reducing overall process energy consumption and embodying a green and low-carbon process design concept. Through recycling, the final emissions are only N2 and H2O after combustion and denitrification, with a small amount of CO2, completely solving environmental problems.

[0020] An apparatus for implementing the above-described method of preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma, comprising: The reactor has a pyrolysis zone, a reaction zone, and a quench zone arranged sequentially along the airflow direction inside. A plasma generator, the inlet of which is connected to a nitrogen source, and the plasma jet outlet which is connected to the pyrolysis zone; A feedstock injector, located in the pyrolysis zone, is used to inject low-carbon hydrocarbon feedstock into the pyrolysis zone; A rapid cooling unit is provided in the rapid cooling zone and is used to introduce a cooling medium into the rapid cooling zone; A cooling and separation unit, connected downstream of the outlet of the reactor, is used to cool and separate the gas-solid mixture from the quench zone. The exhaust gas treatment unit is connected to the gas outlet of the cooling and separation unit and is used to treat ammonia-containing exhaust gas.

[0021] Furthermore, in the reactor, the volume of the reaction zone is 2 to 10 times the volume of the pyrolysis zone. This ratio ensures that the active particles generated by pyrolysis have sufficient space and time to collide, nucleate, and grow into carbon black particles with an ideal structure within the reaction zone, while simultaneously completing the nitrogen-hydrogen synthesis reaction. This is a key equipment structural parameter for achieving high conversion rates and ideal product morphology.

[0022] Furthermore, the pyrolysis zone is provided with at least one plasma generator port and at least one raw material injector; the quench zone is provided with at least one cooling medium inlet.

[0023] Furthermore, the cooling and separation unit includes a first heat exchanger and a gas-solid separation device. The inlet and outlet of the first heat exchanger are connected. The first heat exchanger cools the gas-solid mixed gas flow, and the waste heat is used for power generation. The inlet of the gas-solid separation device is connected to the outlet of the first heat exchanger.

[0024] The high-performance conductive carbon black prepared by this invention is a high-structure, high-conductivity carbon black material. With its small particle size, large specific surface area, and low resistivity, it is used as a conductive filler or functional additive in various industrial fields. Its applications are wide-ranging, mainly covering the following aspects: Electronic and Electromagnetic Shielding: Conductive carbon black is used in the manufacture of conductive plastics, conductive rubber, and antistatic materials. It is suitable for electronic component packaging films, static eliminators, printed circuits, conductive inks, and cable shielding materials, effectively achieving electromagnetic shielding and antistatic protection.

[0025] Energy storage and conversion: In the field of batteries, conductive carbon black is used as a conductive agent in lithium-ion batteries, lead-acid batteries and supercapacitors to improve the charge transport efficiency, energy density and cycle stability of electrode materials; in solid-state batteries, it can also enhance ionic conductivity and structural toughness.

[0026] Rubber and Plastic Products: This material is used to produce conductive rubber (such as antistatic conveyor belts and charging rollers) and conductive plastics (such as cable materials and mining pipes). It plays a key role in antistatic packaging, rubber tires, and electronic device housings. It can achieve excellent conductivity with low addition levels while maintaining the mechanical properties of the base material.

[0027] Industrial Antistatic Solutions: Conductive carbon black is widely used in explosion-proof cables, antistatic boxes, hollow boards, carpets, and medical rubber products, meeting the high standards of electrostatic protection required by industries such as aerospace, weaponry, and chemicals.

[0028] Emerging technology fields: In flexible electronics, catalyst supports and environmental remediation, the high specific surface area and conductivity of conductive carbon black make it suitable for use in flexible displays, smart touch screens and composite catalysts, driving its innovative applications in new energy and environmental protection technologies.

[0029] The beneficial effects of this invention are as follows: This invention has a reasonable design and a simple preparation method, and has the following advantages: (1) Good economic efficiency: The technology of producing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma has high conversion efficiency, lower cracking temperature, and significantly lower unit product power consumption than existing technologies; the electrodes of the plasma generator do not work in oxidizing or reducing environments, greatly extending electrode life and increasing the single working time of the plasma generator, reducing equipment maintenance costs and parts replacement, thereby further reducing costs; the raw material nitrogen is directly produced from the air using a nitrogen generator, and low-carbon hydrocarbons such as methane and acetylene are cheap and readily available in my country, and the main energy source, electricity, is abundant and cheap in my country, resulting in low carbon black production costs; except for the reactor equipment, the supporting equipment used in this process technology are all mature process equipment, which can be purchased domestically at low prices, reducing equipment investment and lowering the overall product cost; the by-product liquid ammonia is currently available domestically. The promising future demand for this technology as a fertilizer, industrial raw material, and emerging green fuel increases the economic benefits of the industry. The use of heat recovery power generation technology in the quenching and cooling units, and the use of gas-fired power generation for process exhaust gas, effectively recovers heat energy and reuses it for production electricity, reducing power consumption per unit output. This technology allows for large-scale continuous production; currently, a single high-temperature plasma generator can reach over 5000 kW with a service life of over 500 hours, and multiple plasma generators can be installed in a single pyrolysis zone. Large-scale continuous production can effectively reduce production costs. Simultaneously, because the plasma generator electrodes do not operate in environments with strong oxidizing and reducing properties, their lifespan is greatly extended, further reducing equipment maintenance costs. Utilizing high-temperature nitrogen plasma to pyrolyze low-carbon hydrocarbons also avoids carbon buildup in plasma equipment. (2) High safety: The preparation method is carried out in an oxygen-free environment. The low-carbon hydrocarbons such as methane are directly decomposed into carbon black and ammonia by high-temperature nitrogen plasma ionization, avoiding the generation of hydrogen and its possible combustion or oxidation reaction, fundamentally eliminating the risk of generating explosive gas mixtures, and avoiding the generation of toxic byproducts such as carbon monoxide and nitrogen oxides, which significantly improves the safety of the process. The reaction temperature of the high-temperature plasma process can be adjusted by input power, and there is no need to use flammable and explosive combustion aids, which simplifies the safety protection measures. The pressure of the hot gas flow in the reaction vessel is low, only 1 to 1.5 atmospheres, which is relatively safe. Moreover, the entire production device is under positive pressure, which avoids the safety hazards caused by external air entering the device. (3) The product quality is superior and adjustable: The chemical properties of nitrogen (as an inert gas or a weakly reactive gas) and the unique plasma thermal field / chemical environment make the carbon black growth process more controllable and easy to obtain products with high structure and high purity; by adjusting key process parameters (such as the power of the plasma generator, the rate and position of hydrocarbon feed, the reactor pressure, the quenching rate, etc.), a variety of nanostructured carbon materials (carbon nanotubes, graphene, conductive carbon black, etc.) can be prepared. (4) Environmentally friendly: The entire process only produces a small amount of carbon dioxide in the exhaust gas combustion power generation unit (produced by the combustion of a small amount of by-product acetylene, HCN, etc.), which is in line with the principles of green chemistry. The main component of the exhaust gas is ammonia, in addition to a small amount of hydrazine (N2H4), a small amount of uncollected carbon black, and trace amounts of hydrogen cyanide (HCN) and acetylene (C2H2). This part of the gas can be recovered by liquid ammonia recovery, purification and concentration device to recover liquid ammonia and carbon black. The exhaust gas is directly burned to generate electricity by gas turbine or internal combustion engine. The exhaust gas has no pollution and is more environmentally friendly. (5) High efficiency: The high energy density provided by plasma enables the pyrolysis reaction to be completed within milliseconds, resulting in compact equipment and high production efficiency; Nitrogen plasma technology can achieve precise temperature and energy input control, which helps to stabilize the reaction process, reduce safety hazards caused by runaway, and avoid the risk of local overheating caused by high-temperature combustion in traditional furnace processes. (6) The preparation method of the present invention does not require the use of any catalyst, thereby avoiding the production of carbon black adhering to the catalyst surface, which would eventually lead to catalyst blockage and failure. (7) The reactor in this invention is an integral module, and multiple reaction modules can be set up according to production needs to adapt to large-scale industrial production. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Figure 1 This is a schematic diagram of the carbon black preparation apparatus in this invention; Figure 2 This is a schematic diagram of the reactor structure in this invention; Figure 3 These are electron microscope images of the carbon black prepared in Example 1; Figure 4These are images showing the appearance of the carbon black prepared in Example 1; Figure 5 This is a schematic diagram of the reaction apparatus in Comparative Example 2.

[0033] In the diagram: 1. Nitrogen generator; 2. First heat exchanger; 3. Second heat exchanger; 4. Gravity dust collector; 5. Cyclone dust collector; 6. Bag filter dust collector; 7. Combustion device; 8. Reactor; 9. Gas separation device; 10. Ammonia storage device; 11. Product collection device. 81. Pyrolysis zone; 82. Plasma generator; 83. Raw material injector; 84. Reaction zone; 85. Quenching zone; 86. Quenching unit; 87. Outlet; 1' Combustion zone of Comparative Example 2; 2' Pyrolysis zone of Comparative Example 2; 3' Reaction zone of Comparative Example 2. Detailed Implementation

[0034] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In a first aspect, the present invention provides a method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma, specifically comprising the following steps: Step S1, System Gas Replacement: Nitrogen gas is introduced into the reactor 8 to replace the air, so that an oxygen-free environment is formed in the entire production system, providing a safe working environment; Step S2, plasma generator start-up: Nitrogen gas is introduced into the plasma generator 82, ionized to form high-temperature nitrogen plasma, which is then introduced into the pyrolysis zone 81 of the reactor 8 to maintain the temperature of the pyrolysis zone 81 at 1400-1800°C. Step S3, Raw material pyrolysis: Low-carbon hydrocarbon raw materials with ≤3 carbon atoms are injected into the high-temperature nitrogen plasma in the pyrolysis zone 81 of the reactor 8. The pyrolysis reaction is carried out under the conditions of 1 to 1.5 atmospheres and residence time of 0.01 to 1 second. The low-carbon hydrocarbon raw materials are pyrolyzed to generate a mixed gas flow containing active particles of carbon, hydrogen and nitrogen. Step S4, Reaction and Nucleation: The mixed gas flow is introduced into the reaction zone 84 of the reactor 8. Under the conditions of 1000-1600℃, 1-1.4 atmospheres, and residence time of 0.05-5 seconds, the carbon active particles are nucleated and grown into carbon black particles. At the same time, the nitrogen active particles and hydrogen active particles react to generate ammonia, forming a high-temperature gas-solid mixed gas flow. Step S5, Rapid Cooling to Terminate the Reaction: The high-temperature gas-solid mixed gas flow from the reaction zone 84 of the reactor 8 is introduced into the rapid cooling zone 85 of the reactor 8 and rapidly cooled to below 800°C within 3 seconds to terminate the reaction. Step S6, Cooling and Collection: The rapidly cooled gas-solid mixture is further cooled, followed by gas-solid separation, and the carbon black product is collected. Step S7, exhaust gas treatment: The exhaust gas after carbon black separation is recycled and reused.

[0038] In step S3, the low-carbon hydrocarbon feedstock is one or more of methane, ethane, ethylene, acetylene, propane, propylene, or propyne.

[0039] In steps S2 and S3, the atomic ratio of the nitrogen gas introduced to the hydrogen atoms in the low-carbon hydrocarbon feedstock is N:H = (0.25~0.5):1.

[0040] In step S5, rapid cooling is performed using one or more of the following methods: pure water spraying, introducing cold nitrogen gas, introducing cold exhaust gas, and heat exchange.

[0041] In step S6, gas-solid separation employs one or more of the following methods: cyclone sedimentation, bag filtration, electrostatic adsorption, water spraying, and metal baffle deposition.

[0042] In step S7, the exhaust gas treatment includes: first, purifying and concentrating the ammonia in the exhaust gas obtained in step S6 to obtain liquid ammonia; then, using the remaining exhaust gas as fuel for power generation.

[0043] The principle of high-temperature nitrogen plasma pyrolysis of low-carbon hydrocarbons mainly involves inelastic collisions between high-energy nitrogen plasma (active particles) and low-carbon hydrocarbon molecules such as methane. This causes the low-carbon hydrocarbon molecules to pyrolyze, generating active hydrogen and carbon particles. The hydrogen and nitrogen particles then react to form ammonia and hydrazine, while the carbon particles form carbon black. In this process, the plasma provides a large number of active particles, such as free electrons, atoms, positive and negative ions, and active free radicals, which can lower the activation energy of the reaction, thereby increasing the reaction rate and conversion rate. Specifically: (1) The technology of preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma is to generate high-energy and high-activity plasma in a high-temperature and oxygen-free environment, using nitrogen as the reactant gas to contact low-carbon hydrocarbon gases, instantly breaking their molecular bonds to generate carbon black. The conversion efficiency is as high as 95%, the cracking temperature is reduced (the cracking temperature is 1400-1800℃, and the energy consumption is reduced). In addition, the plasma generator does not work in an oxidizing and reducing environment, so the electrode life is greatly improved, thereby further reducing the equipment maintenance cost. (2) The technology of preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma is carried out in a high-temperature and oxygen-free environment. Nitrogen gas is used as the reactant gas. The high-energy and high-activity plasma generated by the plasma generator comes into contact with low-carbon hydrocarbon gas and breaks its molecular bonds instantly to generate carbon black. The nitrogen plasma reacts with hydrogen active particles to generate ammonia gas with good stability, which greatly reduces the generation of by-product hydrogen (H2), hydrogen cyanide (HCN), acetylene (C2H2), etc., and improves the yield of carbon black. It has many advantages such as high carbon black purity, low impurities, small particle size, strong conductivity, large specific surface area, and good carbon black structure. It can also meet the requirements of high-end application scenarios (such as conductive additives for lithium batteries, carbon-coated copper foil, special coatings, special heat dissipation coatings, inks, printed circuit boards, etc.). (3) The technology of using high-temperature nitrogen plasma to crack low-carbon hydrocarbons to produce carbon black operates in an oxygen-free environment, which is safer. In addition, the main components of the exhaust gas are ammonia (NH3, more than 90%), uncollected carbon black, a small amount of hydrazine (N2H4) and trace amounts of hydrogen cyanide (HCN) and acetylene (C2H2). When the nitrogen ratio is low, there will be trace amounts of hydrogen (H2). These mixed gases can be used as combustible gases to generate electricity directly by burning gas turbines or internal combustion engines. The exhaust gas is pollution-free and more environmentally friendly. Ammonia can be recovered into liquid ammonia by-product through an ammonia purification and concentration device, which increases economic benefits.

[0044] Secondly, the present invention also provides an apparatus for implementing the above-described method of preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma, such as... Figure 1 and Figure 2 As shown, the device includes: The reactor 8 has a cracking zone 81, a reaction zone 84 and a quenching zone 85 arranged sequentially along the airflow direction inside it. The plasma generator 82 has its inlet connected to a nitrogen source and its plasma jet outlet connected to the pyrolysis zone 81. The feed injector 83 is located in the cracking zone 81 and is used to inject low-carbon hydrocarbon feed into the cracking zone 81. A rapid cooling unit 86 is located in the rapid cooling zone 85 and is used to introduce cooling medium into the rapid cooling zone 85. The cooling and separation unit is connected downstream of the outlet 87 of the reactor 8 and is used to cool and separate the gas-solid mixture from the quench zone. The exhaust gas treatment unit is connected to the gas outlet of the cooling and separation unit and is used to treat ammonia-containing exhaust gas.

[0045] The air inlet of the plasma generator 82 is connected to a nitrogen source, and the nitrogen is obtained by separating air from nitrogen generator 1. The raw materials are readily available, which reduces production costs.

[0046] In reactor 8, the volume of reaction zone 4 is 2 to 10 times that of pyrolysis zone 1.

[0047] The pyrolysis zone 81 is provided with at least one plasma generator 82 port and at least one raw material injector 83; the quench zone 85 is provided with at least one cooling medium inlet.

[0048] The cooling and separation unit includes a first heat exchanger 2 and a gas-solid separation device. The inlet and outlet 87 of the first heat exchanger 2 are connected. The first heat exchanger 2 cools the gas-solid mixed gas flow, and the waste heat is used for power generation. The inlet of the gas-solid separation device is connected to the outlet of the first heat exchanger 2.

[0049] The gas-solid mixture discharged from outlet 87 of reactor 8 first passes through the first heat exchanger 2 for heat exchange and cooling, and then passes through gravity dust collector 4 and cyclone dust collector 5 in sequence for gas-solid separation. The carbon black separated by gravity dust collector 4 and cyclone dust collector 5 enters product collection device 11.

[0050] A second heat exchanger 3 is installed on the low-carbon hydrocarbon feed pipeline. The second heat exchanger 3 cools the gas discharged from the cyclone dust collector 5 again, while simultaneously heating the low-carbon hydrocarbon feed entering the reactor 8, which can effectively reduce production energy consumption. The gas discharged from the second heat exchanger 3 enters the bag filter 6 for further gas-solid separation. The carbon black separated by the bag filter 6 enters the product collection device 11, and the gas discharged from the bag filter 6 enters the tail gas treatment unit.

[0051] The exhaust gas treatment unit includes a gas separation device 9 connected to the outlet of the bag filter 6. The main components of the exhaust gas are ammonia (NH3, over 90%), uncollected carbon black, a small amount of hydrazine (N2H4), and trace amounts of hydrogen cyanide (HCN) and acetylene (C2H2). When the nitrogen content is low, trace amounts of hydrogen (H2) may be present. After separation in the exhaust gas separation device 9, liquid ammonia is stored in the ammonia storage device 10; the remaining gases enter the combustion device 7, where they are converted into CO2 and water, resulting in pollution-free exhaust. Oxygen produced by the nitrogen generator 1 participates in combustion in the combustion device 7, improving utilization efficiency. The combustion device 7 uses a gas turbine or an internal combustion engine.

[0052] The carbon black prepared by this invention has the following characteristics: Microstructure: The average primary particle size ranges from 10 to 300 nm, and the aggregates exhibit a grape-like morphology. The DBP absorbance is 200 to 400 mL / 100g. Surface properties: Specific surface area (BET) is 30-100 m² / g, surface functional groups are mainly CC, with a small amount of CN and C=N nitrogen functional groups (a small amount of nitrogen doping may be introduced due to the nitrogen atmosphere), and volatile matter content is less than 0.1%; Chemical purity: Ash content less than 0.1%, extremely low content of metallic impurities; Performance: Conductive carbon black can effectively reduce physical internal resistance, alleviate electrode polarization, and improve rate performance and cycle stability in batteries; it is suitable for high energy density batteries.

[0053] A single high-temperature plasma generator can reach over 5000 kW and have a service life of over 500 hours. The aforementioned plasma generators are used in large-scale industrial production. In the following embodiments, a 200 kW plasma generator is used, which is of laboratory scale.

[0054] Example 1 The method for preparing carbon black by high-temperature nitrogen plasma pyrolysis of low-carbon hydrocarbons in this embodiment specifically includes the following steps: (1) Nitrogen (N2) is introduced into the furnace body of reactor 8 to replace all other gases in the carbon black production system with nitrogen; (2) A 200kW plasma generator 82 was used, and nitrogen gas with a purity of 99.99% (flow rate 100m³ / h) was introduced. 3 / h) generates a plasma flame, causing the temperature inside the pyrolysis chamber 81 to reach above 1460℃; (3) Methane (purity 95%) (flow rate 138.5 m³ / h) 3 / h) is injected radially from the sides (four directions) of the cracking zone 81 to maintain the temperature of the cracking zone 81 above 1460℃ and the pressure of the cracking zone 81 at 1.35 atmospheres; within the cracking zone 81, methane is converted into active particles of carbon and hydrogen. (4) The mixed gas flow enters the reaction zone 84 from the pyrolysis zone 81. The temperature of the reaction zone 84 rises and is maintained above 1100℃. The pressure of the reaction zone 84 is 1.15 atmospheres. In the reaction zone 84, the carbon ions and carbon atoms / atomic groups produced by pyrolysis rapidly nucleate and collide to grow into primary carbon black particles and aggregates. Nitrogen active particles and hydrogen active particles (all active particles produced by pyrolysis are reacted) generate the main product ammonia. Small amounts of hydrazine (N2H4) and trace amounts of hydrogen cyanide (HCN) and acetylene (C2H2) are produced. When the nitrogen ratio is low, there will be trace amounts of hydrogen (H2). (5) The high-temperature gas-solid mixture after the reaction in reaction zone 84 enters the rapid cooling zone 85. Pure water spray and cold nitrogen inert gas are introduced to quickly reduce the temperature to below 800℃, thereby terminating the further reaction between the substances in the gas stream to generate other substances (such as acetylene C2H2, hydrogen cyanide HCN, etc.). (6) After the gas-solid mixture gas flow is rapidly cooled in the rapid cooling zone 85 to terminate the reaction, it is further cooled by the first heat exchanger 2 to below 300°C, and the remaining heat can be used for power generation. (7) The gas-solid mixed airflow enters the separation and collection system, and the carbon black product is collected by gravity dust collector 4 and cyclone dust collector 5 through cyclone gravity settling. The separated gas enters the second heat exchanger 3 to cool down to below 150°C again. The cooled gas enters the bag filter 6 to collect the carbon black product again. Lowering the temperature to below 150°C can reduce the damage to the bag filter 6 and facilitate the extension of the service life of the bag filter 6. (8) The exhaust gas is discharged after treatment. The main components of the exhaust gas after carbon black separation are ammonia, uncollected carbon black, a small amount of hydrazine (N2H4), and trace amounts of hydrogen cyanide (HCN) and acetylene (C2H2). When the nitrogen ratio is low, a trace amount of hydrogen (H2) will be generated. These gases first enter the gas separation device 9 to separate the ammonia. Then the remaining exhaust gas is used as a combustible gas for direct combustion to generate electricity, and no pollutants are discharged after utilization. The separated ammonia is purified and concentrated to become liquid ammonia, which enters the storage device 10.

[0055] Figure 3 These are electron microscope images of the carbon black prepared in Example 1. In the image, a is at a magnification of 15,000x, b is at a magnification of 10,000x, c is at a magnification of 20,000x, and d is at a magnification of 25,000x.

[0056] Figure 4 This is an appearance diagram of the carbon black prepared in Example 1.

[0057] Example 2 The method for preparing carbon black by high-temperature nitrogen plasma pyrolysis of low-carbon hydrocarbons in this embodiment specifically includes the following steps: (1) Nitrogen (N2) is introduced into the furnace body of reactor 8 to replace all other gases in the carbon black production system with nitrogen; (2) A 200kW plasma generator 82 was used, and nitrogen gas with a purity of 99.99% (flow rate 100m³ / h) was introduced. 3 / h) generates a plasma flame, causing the temperature inside the pyrolysis chamber 81 to reach above 1580℃; (3) Add acetylene (purity 98%) (flow rate 204.1 m³ / h) 3 / h) is injected radially from the side (four directions) of the pyrolysis zone 81 to maintain the temperature of the pyrolysis zone 81 above 1580℃ and the pressure of the pyrolysis zone 81 at 1.2 atmospheres; (4) The mixed gas flow enters the reaction zone 84 from the pyrolysis zone 81. The temperature of the reaction zone 84 rises and is maintained above 1000°C. The reaction zone 84 is at 1.1 atmospheres. (5) The high-temperature gas-solid mixture gas flow after the reaction in reaction zone 84 enters the rapid cooling zone 85, and is sprayed with pure water and introduced with cold nitrogen inert gas to quickly reduce the temperature to below 800℃. (6) After the gas-solid mixture gas flow is rapidly cooled in the rapid cooling zone 85 to terminate the reaction, it is further cooled by the first heat exchanger 2 to below 300°C. (7) The gas-solid mixed gas flow enters the separation and collection system, and the carbon black product is collected by gravity dust collector 4 and cyclone dust collector 5 through cyclone gravity settling. The separated gas enters the second heat exchanger 3 to cool down to below 150°C again, and the cooled gas enters the bag filter 6 to collect the carbon black product again. (8) The exhaust gas is discharged after treatment.

[0058] Example 3 The method for preparing carbon black by high-temperature nitrogen plasma pyrolysis of low-carbon hydrocarbons in this embodiment specifically includes the following steps: (1) Nitrogen (N2) is introduced into the furnace body of reactor 8 to replace all other gases in the carbon black production system with nitrogen; (2) A 200kW plasma generator 82 was used, and nitrogen gas with a purity of 99.99% (flow rate 100m³ / h) was introduced. 3 / h) generates a plasma flame, causing the temperature inside the pyrolysis chamber 81 to reach above 1650℃; (3) Propylene (purity 98%) (flow rate 136.1 m³ / h) 3 / h) is injected radially from the side (four directions) of the pyrolysis zone 81 to maintain the temperature of the pyrolysis zone 81 above 1650℃ and the pressure of the pyrolysis zone 81 at 1.3 atmospheres; (4) The mixed gas flow enters the reaction zone 84 from the pyrolysis zone 81. The temperature of the reaction zone 84 rises and remains above 1000°C. The pressure of the reaction zone 84 is 1.15 atmospheres. (5) The high-temperature gas-solid mixture gas flow after the reaction in reaction zone 84 enters the rapid cooling zone 85, and is sprayed with pure water and introduced with cold nitrogen inert gas to quickly reduce the temperature to below 800℃. (6) After the gas-solid mixture gas flow is rapidly cooled in the rapid cooling zone 85 to terminate the reaction, it is further cooled by the first heat exchanger 2 to below 300°C. (7) The gas-solid mixed gas flow enters the separation and collection system, and the carbon black product is collected by gravity dust collector 4 and cyclone dust collector 5 through cyclone gravity settling. The separated gas enters the second heat exchanger 3 to cool down to below 150°C again, and the cooled gas enters the bag filter 6 to collect the carbon black product again. (8) The exhaust gas is discharged after treatment.

[0059] Comparative Example 1 The difference from Example 1 is that, in this comparative example, argon is used instead of nitrogen in the gas entering the plasma generator 82.

[0060] Comparative Example 2 The difference from Example 1 is that this comparative example does not provide a plasma jet. Implementation: An oil furnace combustion heating system is used, the plasma torch is removed, and natural gas and air are heated by combustion using a combined air and gas method. To maintain the heat supply, the natural gas flow rate is adjusted to 100 Nm³. 3 / h, air flow rate 500 Nm 3 / h.

[0061] like Figure 5 As shown, the reaction apparatus of this comparative example has a combustion zone 1', a pyrolysis zone 2', and a reaction zone 3' arranged sequentially inside. In the combustion zone 1', natural gas enters along the central axis and air enters along the outer axis. The natural gas and air are mixed and burned in a swirling motion in the same direction to obtain a mixed gas. The mixed gas after combustion enters the pyrolysis zone 2' of this comparative example. At the same time, the feed oil sprayed from the atomizing nozzle enters the pyrolysis zone 2' along the outer axis and comes into contact with the mixed gas to undergo a high-temperature pyrolysis reaction. The atomization spray angle of the feed oil is 45°, and the average temperature of the pyrolysis zone 2' is 1900℃. The gas discharged from the pyrolysis zone 2' stays in the reaction zone 3' before being discharged for collection and tail gas treatment. The residence time in the reaction zone 3' is 520ms.

[0062] Test case The reference sample (Swiss SuperP high conductivity carbon black), samples prepared in Examples 1 to 3, Comparative Examples 1 and 2 were tested, and the test results are shown in Table 1.

[0063] Table 1 Test Results

[0064] In Table 1, the specific surface area was determined according to GB / T 3780.5-2017 standard, the iodine uptake value was determined according to GB / T 3780.1-2015 standard, the DBP absorption value was determined according to GB / T 3780.2-2017 standard, the ash content was determined according to GB / T 3780.10-2017 standard, the resistivity was determined according to GB / T 3781.9-2019 standard, and the metallic impurities were determined according to GB / T 3780.12-2007 standard.

[0065] The carbon black products prepared in Examples 1 to 3 had an average particle size of 50 nm and a maximum BET specific surface area of ​​82 m². 2 / g, with a maximum DBP absorption value of 305 mL / 100g, and ash content <0.01%.

[0066] Combining Table 1 and Figure 3 (Electron microscopy image) shows that the carbon atoms in the carbon black prepared by this invention have a strong aggregation effect, the aggregates exhibit a grape-like morphology, small particle size, and high specific surface area performance.

[0067] The above-mentioned carbon black forms offer the following benefits: It has high dispersibility and porous structure, small particle size: nano-sized particles (average 10um or more), a large number of particles per unit volume, and is easy to form a network channel; Porosity: It contains micropores (>2nm) and mesopores (2-50nm), which significantly increases the specific surface area and promotes charge dispersion; Surface characteristics: High surface cleanliness, few functional groups, reducing resistance to electron migration; The aggregate structure is characterized by chain-like or grape-like aggregates, which are loosely packed and form a highly structured structure. Highly structured carbon black has a high oil absorption value and easily forms a stable conductive network; Wide particle size distribution: Carbon black with a wide average particle size distribution, although fewer large particles, can be compensated for by smaller particles, resulting in better overall conductivity. In contrast, the carbon black prepared in Comparative Examples 1 and 2 has a slightly lower structure (DBP absorbance values ​​of 230 mL / 100g and 180 mL / 100g, respectively), and cost analysis in Comparative Example 1 shows an increase in gas cost (argon) of about 40%; the higher temperatures required for pyrolysis in Comparative Examples 1 and 2 also increase energy consumption costs.

[0068] In summary, the present invention aims to provide a method and apparatus for preparing conductive carbon black that is simple in process, low in energy consumption, low in cost, uses readily available and inexpensive raw materials, is safe and environmentally friendly, and has highly adjustable product properties. Specific advantages are as follows: (1) The technology of preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma is to generate high-temperature plasma in a high-temperature oxygen-free environment, using nitrogen as the reaction gas to contact low-carbon hydrocarbon gases, instantly breaking their CH molecular bonds to generate carbon black. The conversion efficiency is high (up to 95%), and the temperature required to crack the CH bonds is reduced (the cracking temperature is 150-250 degrees lower than other processes, and the energy consumption is reduced), which greatly reduces the production cost. (2) The technology of preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma has greatly improved the life of the electrodes of the plasma generator because they do not work in an environment with strong oxidizing and reducing properties. It also avoids carbon buildup on the electrode equipment, reduces equipment maintenance, and further reduces costs. (3) The technology of preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma is to generate high-temperature plasma in a high-temperature and oxygen-free environment, with nitrogen as the reactant gas and contacting low-carbon hydrocarbon gases through a plasma generator to break their CH bonds and generate carbon black. It has many advantages such as high purity, low impurities, small particle size and strong conductivity, large specific surface area and good carbon black structure. It can also meet the requirements of high-end application scenarios (such as conductive additives for lithium batteries, carbon-coated copper foil, special coatings, special heat dissipation coatings, inks, printed circuit boards, etc.). (4) The technology of using high-temperature nitrogen plasma to crack low-carbon hydrocarbons to prepare carbon black is carried out in an oxygen-free environment, which is safer. In addition, the main component of the exhaust gas is ammonia, and there are also small amounts of hydrazine (N2H4) and trace amounts of hydrogen cyanide (HCN), acetylene (C2H2) and nitrogen (N2). This part of the gas can be recovered and then directly burned by a gas turbine or internal combustion engine to generate electricity. The exhaust gas does not cause pollution and is more environmentally friendly. (5) The technology of using high-temperature nitrogen plasma to crack low-carbon hydrocarbons to prepare carbon black can recover ammonia in the tail gas and sell it as a by-product. Liquid ammonia is an emerging green fuel that can replace hydrogen and petroleum fuel. It is safer, easier to transport and cheaper than hydrogen produced by the existing plasma method, and has better economic benefits. (6) The technology of producing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma can obtain high-purity nitrogen directly from the atmosphere using a nitrogen generator. The technology is mature, convenient and inexpensive. Low-carbon hydrocarbons are inexpensive and readily available in my country, especially methane gas, which is abundant in western and northwestern neighboring countries. The required electricity is plentiful and inexpensive in western my country, resulting in very low production costs for conductive carbon black. (7) The technology of preparing carbon black by cracking low-carbon hydrocarbons using high-temperature nitrogen plasma is simple in process, simple in equipment and easy to operate and control. As long as the cracking reaction control temperature and feed ratio are adjusted, it can be directly used as raw material carbon to produce conductive carbon black from methane, acetylene, ethylene, ethane, propane, propylene and propyne. (8) The technology of using high-temperature nitrogen plasma to crack low-carbon hydrocarbons to prepare carbon black, except for the reactor (cracking reaction equipment) which needs to be redesigned, other nitrogen generators, plasma generators, heat exchange equipment, waste heat recovery power generation, collection system, ammonia purification and concentration equipment, gas power generation or internal combustion engine, etc. are all mature process equipment, which are easy to purchase in China and are inexpensive. (9) The technology of using high-temperature nitrogen plasma to crack low-carbon hydrocarbons to prepare carbon black can produce liquid ammonia as a byproduct, avoiding the troubles of purification, recovery, storage and transportation of byproduct hydrogen, as well as its flammability and explosiveness, thus reducing investment and increasing economic benefits. (10) This process technology can be used for large-scale continuous production. Currently, the power of a single plasma generator can reach more than 5000KW and the service life can reach more than 500 hours. Moreover, multiple plasma generators can be installed in one pyrolysis zone. Large-scale continuous production can effectively reduce production costs.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma, characterized in that: Specifically, the steps include the following: Step S1, System gas replacement: Nitrogen gas is introduced into the reactor (8) to replace the air, so that an oxygen-free environment is formed in the entire production system, providing a safe working environment; Step S2, plasma generator start-up: Nitrogen gas is introduced into the plasma generator (82) to ionize and form high-temperature nitrogen plasma, which is then introduced into the pyrolysis zone (81) of the reactor (8) to maintain the temperature of the pyrolysis zone (81) at 1400-1800°C. Step S3, raw material pyrolysis: Low-carbon hydrocarbon raw materials with ≤3 carbon atoms are injected into the high-temperature nitrogen plasma in the pyrolysis zone (81) of the reactor (8), and the pyrolysis reaction is carried out under the conditions of 1 to 1.5 atmospheres and residence time of 0.01 to 1 second. The low-carbon hydrocarbon raw materials are pyrolyzed to generate a mixed gas flow containing nitrogen, carbon and hydrogen active particles. Step S4, Reaction and Nucleation: The mixed gas flow is introduced into the reaction zone (84) of the reactor (8). Under the conditions of 1000-1600℃, 1-1.4 atmospheres, and residence time of 0.05-5 seconds, the nitrogen, carbon, and hydrogen active particles in the mixed gas flow react rapidly in the reaction zone to generate carbon black particles and ammonia, forming a high-temperature gas-solid mixed gas flow. Step S5, rapid cooling to terminate the reaction: The high-temperature gas-solid mixed gas flow from the reaction zone (84) of the reactor (8) is introduced into the rapid cooling zone (85) of the reactor (8) and rapidly cooled to below 800°C within 3 seconds to terminate the reaction; Step S6, Cooling and Collection: The rapidly cooled gas-solid mixture is further cooled, followed by gas-solid separation, and the carbon black product is collected. Step S7, exhaust gas treatment: The exhaust gas after carbon black separation is recycled and reused.

2. The method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 1, characterized in that: In step S3, the low-carbon hydrocarbon raw material is one or more of methane, ethane, ethylene, acetylene, propane, propylene, or propyne.

3. The method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 1, characterized in that: In steps S2 and S3, the atomic ratio of nitrogen gas introduced to hydrogen atoms in the low-carbon hydrocarbon feedstock is N:H = (0.25~0.5):

1.

4. The method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 1, characterized in that: In step S5, rapid cooling is performed using one or more of the following methods: pure water spraying, introducing cold nitrogen gas, introducing cold exhaust gas, and heat exchange.

5. The method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 1, characterized in that: In step S6, the gas-solid separation employs one or more of the following methods: cyclone sedimentation, bag filtration, electrostatic adsorption, water spraying, and metal baffle deposition.

6. The method for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 1, characterized in that: In step S7, the exhaust gas treatment includes: first, purifying and concentrating the ammonia in the exhaust gas obtained in step S6 to obtain liquid ammonia; then, using the remaining exhaust gas as fuel for combustion and power generation.

7. An apparatus for implementing the method for preparing carbon black by high-temperature nitrogen plasma pyrolysis of low-carbon hydrocarbons as described in any one of claims 1 to 6, characterized in that: include: The reactor (8) has a cracking zone (81), a reaction zone (84) and a quenching zone (85) arranged sequentially along the airflow direction inside. The plasma generator (82) has its inlet connected to a nitrogen source and its plasma jet outlet connected to the pyrolysis zone (81). A feedstock injector (83) is provided in the pyrolysis zone (81) for injecting low-carbon hydrocarbon feedstock into the pyrolysis zone (81); A rapid cooling unit (86) is disposed in the rapid cooling zone (85) for introducing a cooling medium into the rapid cooling zone (85); A cooling and separation unit is connected downstream of the outlet (87) of the reactor (8) for cooling and separating the gas-solid mixture from the quench zone; The exhaust gas treatment unit is connected to the gas outlet of the cooling and separation unit and is used to treat ammonia-containing exhaust gas.

8. The apparatus for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 7, characterized in that: In the reactor (8), the volume of the reaction zone (4) is 2 to 10 times the volume of the pyrolysis zone (1).

9. The apparatus for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 7, characterized in that: The pyrolysis zone (81) is provided with at least one plasma generator (82) port and at least one raw material injector (83); the quench zone (85) is provided with at least one cooling medium inlet.

10. The apparatus for preparing carbon black by pyrolyzing low-carbon hydrocarbons using high-temperature nitrogen plasma according to claim 7, characterized in that: The cooling and separation unit includes a first heat exchanger (2) and a gas-solid separation device. The inlet and outlet (87) of the first heat exchanger (2) are connected. The first heat exchanger (2) cools the gas-solid mixed airflow, and the waste heat is used for power generation. The inlet of the gas-solid separation device is connected to the outlet of the first heat exchanger (2).

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