Structure and control method of carbon nanotube reactor with parallel bypass and variable flow channel cross-section
By using a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section, the problems of low mass transfer efficiency and high energy consumption in the traditional preparation process are solved, realizing efficient and low-cost carbon nanotube preparation, which is suitable for large-scale industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NUCLEAR POWER INSTITUTE OF CHINA
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-02
AI Technical Summary
Existing carbon nanotube preparation processes suffer from problems such as low mass transfer efficiency, difficulty in separating catalysts from products, uneven gas distribution, low reaction conversion rate, discontinuous process flow, high system energy consumption, and poor raw material adaptability, resulting in high production costs and making it difficult to achieve large-scale industrial applications.
The reactor structure employs a carbon nanotube reactor with parallel bypass and variable flow channel cross-section, including multiple variable diameter reaction channels and variable diameter side channels. Combined with a molten salt heating system, hydrogen recovery device and intelligent valve control, it achieves efficient mass and heat transfer between gas and solid phases, and improves product quality through multi-stage pressurization and shaping treatment.
It significantly improves the carbon dioxide conversion rate to over 85%, the hydrogen recovery and utilization rate reaches 95%, reduces energy consumption by 30-35%, has a high catalyst recycling rate, adapts to different concentrations of raw materials and catalysts, and is suitable for large-scale continuous production.
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Figure CN122124709A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanomaterial preparation technology, specifically to a carbon nanotube reactor structure and control method with parallel bypass and variable flow channel cross-section. Background Technology
[0002] With the maturation of carbon capture technology, how to efficiently utilize the captured carbon dioxide has become an urgent problem to be solved. Directly converting captured carbon dioxide into carbon nanotubes can not only achieve the recycling of carbon resources but also meet market demand for nanomaterials, resulting in significant environmental and economic benefits. Currently, this technology has become an important research direction in the field of carbon capture and utilization, attracting widespread attention from academia and industry.
[0003] Traditional carbon nanotube preparation processes mainly include arc flash, laser ablation, and chemical vapor deposition (CVD). Among these, CVD is the most commonly used method due to its simple equipment, convenient operation, and high yield. A typical process involves mixing captured carbon dioxide with a reducing gas and then introducing the mixture into a reactor. A reduction reaction occurs under the action of a catalyst, and the generated carbon atoms deposit and grow on the catalyst surface to form carbon nanotubes. The reaction temperature is generally controlled between 600 and 900°C, and the pressure is maintained between atmospheric pressure and 1 MPa. The catalyst is often a transition metal nanoparticle such as iron, cobalt, or nickel.
[0004] However, existing technologies face numerous challenges in industrial application: First, the captured carbon dioxide often contains impurities such as moisture and oxygen, which can poison the catalyst and reduce reaction efficiency. Second, the traditional reactor structure is poorly designed, resulting in uneven gas residence time distribution, leading to poor uniformity in carbon nanotube growth and the presence of amorphous carbon and other byproducts in the product. Furthermore, current processes are energy-intensive, with a large amount of heat energy not effectively recovered and utilized, increasing production costs. In addition, short catalyst lifespan and difficulty in regeneration also hinder the development of this technology. These technical bottlenecks keep the production cost of carbon nanotubes high, severely impacting their large-scale application.
[0005] Patent document CN120887410A discloses a chain-type conveying production device for preparing carbon nanotubes, which achieves mass production of carbon nanotubes through continuous conveying of material boxes in a closed pipeline. Although the device achieves automated material conveying, its fixed reactor structure and single temperature zone design limit the precise control of reaction conditions, and it fails to achieve the direct conversion and utilization of carbon dioxide as a raw material.
[0006] Patent document CN120664535A discloses a method for preparing carbon nanotubes by plasma pretreatment-impregnation deposition, which enhances the surface roughness of the substrate through plasma treatment to improve catalyst distribution. Although this method improves the uniformity of catalyst dispersion, its substrate-dependent preparation mode limits the product yield, and the complex pretreatment process increases the process cost, presenting a significant bottleneck for continuous production.
[0007] The literature "Water transport through carbon nanotubes with a peanut-shaped cross-section" studied the preparation method of carbon nanotubes with special morphology, but its process is complicated and the yield is low, making it impossible to achieve large-scale production.
[0008] In summary, existing carbon nanotube preparation processes suffer from a series of problems: low mass transfer efficiency in traditional reactors, difficulty in separating catalysts from products; uneven gas distribution, resulting in low reaction conversion rates; discontinuous process flow, leading to high system energy consumption; and poor raw material adaptability, making it difficult to handle different concentrations of captured carbon dioxide. These problems severely restrict the industrial production of carbon nanotubes. Summary of the Invention
[0009] In view of the problem of low reaction conversion rate in current carbon nanotube reactors, the purpose of this invention is to provide a carbon nanotube reactor structure and control method with parallel bypass and variable flow channel cross section. This reactor structure can increase the carbon dioxide conversion rate to more than 85%, fully demonstrating its technical advantages in industrial production.
[0010] This invention is achieved through the following technical solution:
[0011] In a first aspect, the present invention provides a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section, including a floating bed reactor containing multiple variable diameter reaction channels, wherein multiple air inlet branches are connected to the multiple variable diameter reaction channels, and each air inlet branch is connected to a control valve; variable diameter side channels are connected to the multiple variable diameter reaction channels, and the variable diameter side channels are arranged in parallel with the multiple variable diameter reaction channels.
[0012] Each segment of the multi-section variable-diameter reaction channel can be connected to a molten salt heating system to achieve zoned temperature control.
[0013] A shaping device can be connected to the outlet of the multi-stage variable-diameter reaction channel. This mechanical hot-press shaping device utilizes a combination of multi-stage pressurization and temperature control to densify the carbon nanotube product. When the carbon nanotube material enters the pressing chamber of the mechanical hot-press shaping device, it is first pre-compacted by a pre-pressing device. Then, progressive pressure is applied during the main pressing stage to promote tight bonding between the carbon nanotube bundles. Finally, the product structure is stabilized through a holding pressure stage. The entire pressing process is conducted under a controllable temperature environment. Pressing parameters are automatically adjusted by real-time monitoring of the product density to ensure that a carbon nanotube product with ideal bulk density and structural integrity is obtained. This achieves the direct conversion of carbon nanotubes. Furthermore, when the raw material properties remain constant but the product density is low, increasing the processing pressure improves the densification degree, gradually improving product quality. Conversely, when the raw material properties remain constant but the product density is high, decreasing the processing pressure makes the product structure more uniform, further optimizing product quality.
[0014] Furthermore, multiple intake branch pipes are connected to the same intake main pipe via multi-port connectors, and a heating structure is connected to the intake main pipe.
[0015] Furthermore, the heating structure is a molten salt heating system.
[0016] Furthermore, an exhaust pipe is connected to the multi-section variable diameter reaction channel, and the exhaust pipe is connected to a hydrogen recovery device.
[0017] Furthermore, the hydrogen recovery device includes an injector connected to the exhaust pipe, the injector being connected to a membrane separation unit, the membrane separation unit being connected to a pressure swing adsorption system, and the top of the pressure swing adsorption system being connected to a first hydrogen recycling pipeline connected to the main intake pipe.
[0018] Furthermore, the membrane separation unit and the pressure swing adsorption system are connected at the bottom to a second hydrogen recycling pipeline that is connected to the main gas inlet pipe.
[0019] The membrane separation unit employs a multi-stage membrane structure. The mixed gas generated during the reaction enters the membrane separation unit, where a hydrogen-rich permeate gas is separated. The remaining impermeable gas enters the pressure swing adsorption system, where high-purity hydrogen is further separated. The separated hydrogen is returned to the reaction system via a reuse pipeline to continue participating in the reaction. The use of multi-stage adsorption towers achieves continuous and efficient hydrogen recovery. The recovered hydrogen, after pressurization, is directly returned to the reactor for recycling. This structure replaces the traditional direct emission process, significantly reducing the consumption of raw material gases and improving the resource utilization efficiency and economy of the entire system.
[0020] Furthermore, a power line is connected between the second hydrogen recycling pipeline and the injector, and a power pump is connected to the power line.
[0021] Furthermore, the pressure swing adsorption system is connected to an external hydrogen gas inlet pipe at the top.
[0022] Furthermore, the multi-section variable diameter reaction channel is connected to other auxiliary gas inlet pipes and catalyst feed pipes.
[0023] Secondly, this application provides a control method for a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section. The raw material gas enters the cavity corresponding to the multi-section variable diameter reaction channel through independent branch pipes. The opening degree of the through-hole regulating control valve controls the intake of the raw material gas. When an abnormal pressure drop occurs in the multi-section variable diameter reaction channel, the flow is diverted through the variable diameter side channel to ensure the continuous and stable operation of the reaction process. The remaining reaction gas in the multi-section variable diameter reaction channel is introduced into the hydrogen recovery device to realize the recovery and recycling of hydrogen.
[0024] In the reaction process, when the catalyst concentration remains constant and the internal pressure difference of the multi-stage variable diameter reaction channel increases, the reaction can be made more complete by reducing the gas flow rate, and the raw material conversion rate gradually increases. When the catalyst concentration remains constant and the internal pressure difference of the reactor decreases, the reaction intensity can be increased by increasing the gas flow rate, and the raw material conversion rate gradually decreases.
[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0026] (1) The reactor structure of the present invention adopts a multi-segment variable diameter reaction channel, forming an alternating flow cross section inside the reactor. High-speed turbulence is formed in the channel contraction section to enhance mass transfer, and sufficient reaction space is provided in the expansion section, realizing the controllable growth of carbon nanotubes. When the reaction gas flows through the cross-section contraction section, the Venturi effect is generated, forming local high-speed turbulence, which effectively enhances the mass and heat transfer process between the gas and solid phases; while in the cross-section expansion section, the gas flow velocity is reduced, providing sufficient contact reaction time for the catalyst and the reaction gas. In addition, the variable diameter side channel is connected in parallel with the multi-segment variable diameter reaction channel, and the control valve is connected to the intelligent valve control system to realize the dynamic distribution of the reactants. When the pressure drop of the multi-segment variable diameter reaction channel is abnormal, the variable diameter side channel is automatically opened to ensure the continuous and stable operation of the reaction process. This synergistic structure of the multi-segment variable diameter reaction channel and the variable diameter side channel not only realizes the adaptive adjustment of the reaction intensity, but also effectively prevents catalyst deposition and bed blockage through flow channel optimization, significantly improving the operating flexibility and reliability of the reactor.
[0027] (2) The multi-segment variable diameter reaction channel of the present invention can also utilize the turbulent stripping of byproducts in the contraction segment and the stable growth of carbon nanotubes in the expansion segment to optimize the crystallinity of carbon nanotubes and improve the quality of single structures. More importantly, the multi-segment variable diameter reaction channel actively creates a differentiated growth environment with temperature and concentration gradients in the reactor, which allows the precursor to undergo different conditions in different segments, thereby preparing carbon nanotubes from single-walled to multi-walled, or with specific segmented, bamboo-like or other complex structures, realizing the diversification and customization of product structures.
[0028] (3) The hydrogen recovery device connected in this invention can separate and purify the unreacted gas and return it to the floating bed reactor for reuse, thereby improving the utilization rate of raw materials. By setting the reactor as a multi-stage variable diameter structure and connecting it with the hydrogen recovery device, the recycling of raw materials is realized, which significantly improves product quality and production efficiency. It has the advantages of high conversion rate and good product consistency, and provides a reliable technical approach for the green and efficient preparation of carbon nanotubes.
[0029] (4) The reactor structure of the present invention is stable and reliable in operation, and flexible and convenient in regulation. It can not only process carbon dioxide capture raw materials of different concentrations, but also adapt to a variety of catalyst systems. The system has strong raw material adaptability and a wide process operation window. The reactor structure has good prospects for industrial application and can be used for large-scale continuous production.
[0030] (5) The ejector in this invention is the core power structure. It uses a high-pressure power gas source to generate a vacuum effect, providing stable gas flow power for the entire reaction system. The ejector ensures that the reactants form a stable sulfidation state in the multi-stage variable diameter reaction channel by precisely controlling the gas flow rate and pressure parameters, while realizing the efficient recycling of unreacted gas.
[0031] (6) The reactor structure of the present invention realizes the optimization of the reaction process and the recycling of resources, which can increase the carbon dioxide conversion rate to more than 85%, the hydrogen recovery and utilization rate to 95%, and reduce energy consumption by 30%~35%, fully demonstrating its technical advantages in industrial production. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 This is a schematic diagram of a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to the present invention.
[0034] Figure 2 This is a schematic diagram of the variable diameter side channel in this invention.
[0035] Figure label:
[0036] 01-Carbon source inlet pipe, 02-Main inlet pipe, 03-Heating structure, 04-Inlet branch pipe, 05-Other auxiliary gas inlet pipe, 06-Catalyst feed pipe, 07-Control valve, 08-Variable diameter side channel, 09-Multi-stage variable diameter reaction channel, 10-Exhaust pipe, 11-Power pump, 12-Injector, 13-First-stage membrane separation unit, 14-Second-stage membrane separation unit, 15-Pressure swing adsorption system, 16-External hydrogen inlet pipe, 17-First hydrogen recycling pipeline, 18-Second hydrogen recycling pipeline, 19-Mechanical hot pressing shaping device, 20-Hydrogen inlet pipe. Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. The illustrative embodiments and descriptions of this invention are only used to explain this invention and are not intended to limit this invention.
[0038] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known materials or methods have not been specifically described in order to avoid obscuring the invention.
[0039] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples.
[0040] In this application, unless otherwise stated, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "middle," "vertical," "horizontal," "lateral," and "longitudinal," etc., generally refer to the directions shown in the drawings or describe the relative positional relationships of the components in a vertical, perpendicular, or gravitational direction. They are used only to describe the relative positional relationships between the components or constituent parts and do not specifically limit the specific installation orientation of each component or constituent part. "Inner" and "outer" generally refer to the interior or exterior of the cavity relative to the chamber or the radial interior or exterior relative to the center of a circle. The above directional terms are defined for ease of understanding of the present invention and therefore do not constitute a limitation on the scope of protection of the present invention.
[0041] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0042] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0043] Furthermore, the structures, proportions, sizes, etc., drawn in the accompanying drawings of this application are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.
[0044] Example
[0045] like Figure 1 As shown, this embodiment provides a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section, including a floating bed reactor containing multiple variable diameter reaction channels 09. Multiple inlet branch pipes 04 are connected to the multiple variable diameter reaction channels 09, and each inlet branch pipe 04 is connected to a control valve 07. Variable diameter side channels 08 are connected to the multiple variable diameter reaction channels 09, and the variable diameter side channels 08 are arranged in parallel with the multiple variable diameter reaction channels 09. A schematic diagram of the variable diameter side channel 08 is shown below. Figure 2As shown, the small-diameter end of the variable-diameter side channel 08 is connected to the section with the largest cross-section of the multi-section variable-diameter reaction channel 09, and the large-diameter end of the variable-diameter side channel 08 is connected to the section with the smallest cross-section of the multi-section variable-diameter reaction channel 09.
[0046] Specifically, multiple intake branch pipes 04 are connected to the same main intake pipe 02 via multi-port connectors. A heating structure 03, which is a molten salt heating system, is connected to the main intake pipe 02. In other embodiments, each segment of the multi-diameter reaction channel 09 can be connected to a molten salt heating system to achieve zoned temperature control. This allows for personalized regulation through independent temperature control and intake systems, ensuring optimal reaction conditions are maintained in channels of different diameters.
[0047] The intake manifold 02 is connected to the carbon source intake manifold 01 and the hydrogen intake manifold 20 via a multi-port connector.
[0048] Specifically, an exhaust pipe 10 is connected to the multi-section variable-diameter reaction channel 09. The exhaust pipe 10 is connected to a hydrogen recovery device, which includes an injector 12 connected to the exhaust pipe 10. The injector 12 is connected to a membrane separation unit, which is connected to a pressure swing adsorption system 15. The top of the pressure swing adsorption system 15 is connected to a first hydrogen recycling pipeline 17, which is connected to a hydrogen inlet pipe 20. The top of the pressure swing adsorption system 15 is also connected to an external hydrogen vent pipe 16. The bottom of the membrane separation unit and the pressure swing adsorption system 15 is connected to a second hydrogen recycling pipeline 18, which is connected to the main inlet pipe 02. In other embodiments, the second hydrogen recycling pipeline 18 can also be connected to the hydrogen inlet pipe 20. A power pipeline connects the second hydrogen recycling pipeline 18 to the injector 12, and a power pump 11 is connected to the power pipeline.
[0049] Among them, the ejector 12 is the core power structure. It uses a high-pressure power gas source to generate a vacuum effect, providing stable gas flow power for the entire reaction system. The ejector ensures that the reactants form a stable sulfidation state in the multi-section variable diameter reaction channel 09 by precisely controlling the gas flow rate and pressure parameters, while realizing the efficient recycling of unreacted gas.
[0050] The membrane separation unit consists of a primary membrane separation unit 13 and a secondary membrane separation unit 14, forming a bipolar membrane separation structure. This structure can recover and purify more than 95% of the hydrogen in the reaction tail gas and return it to the reaction system for recycling. Furthermore, the primary membrane separation unit 13, the secondary membrane separation unit 14, and the pressure swing adsorption system 15 are all connected to hydrogen recovery pipes at their bottoms. The hydrogen flowing out through these recovery pipes can be introduced into the injector 12 or the inlet pipe, and then into the multi-stage variable diameter reaction channel 09 as feed gas for the reaction.
[0051] Specifically, the multi-stage variable diameter reaction channel 09 is connected to an auxiliary gas inlet pipe 05 and a catalyst feed pipe 06. The auxiliary gas inlet pipe is used to regulate or replenish the feed gas in the multi-stage variable diameter reaction channel 09.
[0052] In other specific embodiments, a mechanical hot-pressing device 19 can be connected to the carbon nanotube outlet of the multi-segment variable-diameter reaction channel 09. This allows the generated carbon nanotubes to directly enter the mechanical hot-pressing device 19. This device can densify the carbon nanotubes through a combination of multi-stage heating and temperature control. After the carbon nanotube material enters the pressing chamber, it is first initially compacted by a pre-pressing device. Then, progressive pressure is applied during the main pressing stage to promote tight bonding between the carbon nanotube bundles. Finally, the product structure is stabilized through a holding pressure stage. The entire pressing process is carried out in a controllable temperature environment. By automatically adjusting the pressing parameters through real-time monitoring of the product density, it is ensured that a carbon nanotube product with ideal bulk density and structural integrity is obtained.
[0053] Working principle: During operation, carbon source gas is introduced into the multi-stage variable-diameter reaction channel 09 through the carbon source inlet pipe 01, and hydrogen gas is introduced into the multi-stage variable-diameter reaction channel 09 through the hydrogen inlet pipe 20. The gas enters different reaction sections through the inlet branch pipe 04. Different flow rates are controlled in each reaction section through the variable-diameter channels. Before the carbon source gas and hydrogen gas enter the multi-stage variable-diameter reaction channel 09, the gas is heated and its temperature controlled by a molten salt heating system connected to the main inlet pipe 02. Simultaneously, a catalyst... The feed pipe 06 introduces a catalyst into the multi-stage variable diameter reaction channel 09, causing the raw material gas to generate carbon nanotubes in the multi-stage variable diameter reaction channel 09. If residual hydrogen is generated during the reaction, it enters the hydrogen recovery device through the exhaust pipe 10. First, it enters the injector 12, and then enters the membrane separation unit for separation, separating a hydrogen-rich permeate gas. The remaining unpermeated gas enters the pressure swing adsorption system, where high-purity hydrogen is further separated. The separated hydrogen is returned to the reaction system through the reuse pipeline to continue participating in the reaction.
[0054] Compared to traditional single-path reaction systems, the multi-channel variable-diameter reaction system in this invention achieves precise control of the reaction process through the coordinated operation of the main channel, side channels, and multiple variable-diameter reaction chambers. The multi-path design enhances the system's operational flexibility, enabling the production process to adapt to different raw material characteristics and product requirements. Compared to traditional carbon nanotube preparation systems, the reactor structure of this invention, through the design of multi-segment variable-diameter channels, the efficient operation of the hydrogen recovery device, and the precise control of the ejector power system, optimizes the reaction process and achieves resource recycling. System operation data shows that this innovative design can increase the carbon dioxide conversion rate to over 85%, achieve a hydrogen recovery rate of 95%, and reduce energy consumption by 30-35%, fully demonstrating its technological advantages in industrial production. Compared to traditional fluidized bed reaction systems, this invention, through the variable-diameter channel design, achieves precise matching of the flow pattern and temperature field in the reaction process, enhances gas-solid mass transfer and reaction selectivity, and improves the growth efficiency and crystal quality of carbon nanotubes. The system is compact and flexible in operation. Compared with traditional fluidized bed reactors, it can reduce investment and energy consumption by 30-40%, and has a high catalyst recycling rate. It is suitable for various operating conditions such as atmospheric pressure and pressurization.
[0055] This invention employs a multi-segment variable-diameter reaction channel 09, forming alternating flow cross-sections within the reactor. High-speed turbulence enhances mass transfer in the constriction section, while ample reaction space is provided in the expansion section, enabling controllable growth of carbon nanotubes. When the reactant gas flows through the constriction section, a Venturi effect is generated, creating localized high-speed turbulence and effectively enhancing the mass and heat transfer process between the gas and solid phases. In the expansion section, the gas velocity decreases, providing sufficient contact time for the catalyst and reactant gases. Furthermore, a variable-diameter side channel 08 is connected in parallel with the multi-segment variable-diameter reaction channel 09, and a control valve 07 is communicatively connected to an intelligent valve control system, enabling dynamic distribution of reactants. When the pressure drop in the multi-segment variable-diameter reaction channel 09 is abnormal, the variable-diameter side channel 08 automatically opens, ensuring continuous and stable operation of the reaction process. This synergistic structure of the multi-segment variable-diameter reaction channel 09 and the variable-diameter side channel 08 not only achieves adaptive adjustment of the reaction intensity but also effectively prevents catalyst deposition and bed blockage through flow channel optimization, significantly improving the reactor's operational flexibility and reliability. In addition, the multi-segment variable diameter reaction channel 09 can also utilize the turbulent stripping of byproducts in the contraction section and the stable growth in the expansion section to optimize the crystallinity of carbon nanotubes and improve the quality of single structures. More importantly, the multi-segment variable diameter reaction channel 09 actively creates a differentiated growth environment with temperature and concentration gradients in the reactor. This allows the precursor to experience different conditions in different sections, thereby enabling the preparation of carbon nanotubes with complex structures such as single-walled to multi-walled or with specific segmental or bamboo-like structures, achieving diversification and customization of product structures.
[0056] The reaction sections of this invention can be coaxially connected by flanges to form a complete reaction system, or they can be configured as an integrally formed structure. The cross-sectional change rate of the multi-segment variable diameter reaction channel 09 can be optimized by adjusting the channel geometry parameters, which improves the flexibility of the reaction process. The channel wall and internal components form a composite reaction surface, which increases the contact area between the gas and solid phases, enhances the mass transfer during the reaction process, and significantly improves the raw material conversion efficiency.
[0057] This invention, by connecting a hydrogen recovery device, allows unreacted gases to be separated by pressure swing adsorption and returned to the multi-stage variable-diameter reaction channel 09 for reuse, thus improving the utilization rate of raw materials. By setting the reactor to a multi-stage variable-diameter structure and connecting it to the hydrogen recovery device, the invention achieves the recycling of raw materials, significantly improving product quality and production efficiency. It boasts advantages such as high conversion rate and good product consistency, providing a reliable technical approach for the green and efficient preparation of carbon nanotubes. It optimizes the reaction process and recycles resources, increasing the carbon dioxide conversion rate to over 85% and the hydrogen recovery rate to 95%, while reducing energy consumption by 30%–35%, fully demonstrating its technological advantages in industrial production.
[0058] Experimental Example 1
[0059] This invention utilizes a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section to convert CO2 into carbon nanotubes. The multi-segment variable-diameter reaction channel has a diameter of 200 mm and consists of four segments with temperatures of 650℃, 700℃, 750℃, and 680℃, a pressure of 0.3 MPa, a gas velocity of 1.0 m / s, and uses iron-cobalt composite nanoparticles as the catalyst. The feed gas CO2 concentration is 30%, and the H2 / CO2 molar ratio is 5:1. The resulting carbon nanotubes have a diameter of 15 nm, a length of 50 μm, a graphitization degree of 85%, and a CO2 conversion rate of 80%.
[0060] Experiment Example 2
[0061] This invention utilizes a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section to convert CO2 into carbon nanotubes. The multi-segment variable-diameter reaction channel has a diameter of 300 mm and consists of five segments with temperatures of 680℃, 720℃, 760℃, 700℃, and 650℃, a pressure of 0.5 MPa, and a gas velocity of 1.5 m / s. The catalyst is nickel-iron composite nanoparticles. The feed gas CO2 concentration is 25%, and the H2 / CO2 molar ratio is 2.5:1. The resulting carbon nanotubes have a diameter of 10 nm, a length of 80 μm, a graphitization degree of 88%, and a CO2 conversion rate of 86%. The system's carbon nanotube yield is 20% higher than that of traditional methods.
[0062] Experimental Example 3
[0063] This invention utilizes a carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section to convert CO2 into carbon nanotubes. The multi-segment variable-diameter reaction channel has a diameter of 250 mm and consists of four segments with temperatures of 660℃, 710℃, 740℃, and 690℃, a pressure of 0.4 MPa, a gas velocity of 1.2 m / s, and cobalt-molybdenum composite nanoparticles as the catalyst. The feed gas CO2 concentration is 35%, and the H2 / CO2 molar ratio is 3:1. The resulting carbon nanotubes have a diameter of 20 nm, a length of 60 μm, a graphitization degree of 82%, a CO2 conversion rate of 83%, and a carbon nanotube yield of 3 kg / h.
[0064] Finally, it should be noted that the specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. For those skilled in the art, it is obvious that this application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic characteristics of the present application. Furthermore, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe various possible combinations separately. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this application is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included within this application.
Claims
1. A carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section, characterized in that, The reactor includes a floating bed reactor containing a multi-section variable diameter reaction channel (09), wherein multiple air inlet branches (04) are connected to the multi-section variable diameter reaction channel (09), and each air inlet branch (04) is connected to a control valve (07); a variable diameter side channel (08) is connected to the multi-section variable diameter reaction channel (09), and the variable diameter side channel (08) is arranged in parallel with the multi-section variable diameter reaction channel (09).
2. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 1, characterized in that, Multiple intake branch pipes (04) are connected to the same intake main pipe (02) through multi-port connectors, and a heating structure (03) is connected to the intake main pipe (02).
3. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 2, characterized in that, The heating structure (03) is a molten salt heating system.
4. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 2, characterized in that, An exhaust pipe (10) is connected to the multi-section variable diameter reaction channel (09), and the exhaust pipe (10) is connected to a hydrogen recovery device.
5. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 4, characterized in that, The hydrogen recovery device includes an injector (12) connected to the exhaust pipe (10), the injector (12) is connected to a membrane separation unit, the membrane separation unit is connected to a pressure swing adsorption system (15), and the top of the pressure swing adsorption system (15) is connected to a first hydrogen recycling pipeline (17) connected to the intake main pipe (02).
6. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 5, characterized in that, The membrane separation unit and pressure swing adsorption system (15) are connected at the bottom to a second hydrogen recycling pipeline (18) that is connected to the main gas inlet (02).
7. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 6, characterized in that, A power line is connected between the second hydrogen recycling line (18) and the injector (12), and a power pump (11) is connected to the power line.
8. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 5, characterized in that, The pressure swing adsorption system (15) is connected to an external hydrogen gas inlet pipe (16) at the top.
9. The carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section according to claim 1, characterized in that, The multi-section variable diameter reaction channel (09) is connected to other auxiliary gas inlet pipes (05) and catalyst feed pipes (06).
10. A method for controlling the carbon nanotube reactor structure with parallel bypass and variable flow channel cross-section as described in any one of claims 1 to 9, characterized in that, The raw material gas enters the cavity corresponding to the multi-section variable diameter reaction channel (09) through an independent branch pipe. The opening of the through-hole regulating control valve (07) controls the intake of the raw material gas. When the pressure drop of the multi-section variable diameter reaction channel (09) is abnormal, the flow is diverted through the variable diameter side channel (08) to ensure the continuous and stable operation of the reaction process. The remaining reaction gas in the multi-section variable diameter reaction channel (09) is introduced into the hydrogen recovery device to realize the recovery and recycling of hydrogen.