Fluidized bed for continuously preparing chiral enriched single-walled carbon nanotubes
By designing a fluidized bed device that combines a catalyst pretreatment reactor and a cooling separator, the problems of high cost and poor stability in the preparation of chiral single-walled carbon nanotubes in traditional methods have been solved, enabling low-cost and efficient continuous preparation of chiral enriched single-walled carbon nanotubes.
Patent Information
- Application Number
- CN202520301674.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2025-01-09
- Filing Date
- 2025-02-25
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2035-02-25
AI Technical Summary
Existing technologies make it difficult to achieve low-cost and efficient preparation of chiral enriched single-walled carbon nanotubes. Traditional catalyst preparation methods suffer from high costs, easy agglomeration of metal particles, and poor performance stability, which limits the application of fluidized bed CVD technology in continuous preparation processes.
A fluidized bed device comprising a catalyst pretreatment reactor, a main reactor, and a cooling separator was designed. Through the synergistic effect of catalyst pretreatment, the main reactor, and the cooling separator, continuous preparation of carbon nanotubes is achieved. By adopting a reasonable device design and process flow, costs are reduced and performance stability is improved.
The continuous preparation of chiral enriched single-walled carbon nanotubes was achieved. The device was reasonably designed, low in cost, and stable and reliable in performance, which improved the preparation efficiency and product purity.
Smart Images
Figure CN223945624U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of carbon nanotubes, and particularly relates to a fluidized bed for continuously preparing chiral enriched single-walled carbon nanotubes. BACKGROUND
[0002] Carbon nanotubes (CNT) are a new type of nanomaterial discovered by Japanese scientist Sumio Iijima, and their characteristics include small size, cylindrical structure, and extremely high aspect ratio. Carbon nanotubes have excellent tensile strength, high modulus, large aspect ratio, low density, good chemical and environmental stability, and excellent thermal and electrical conductivity, and are a high-performance carbon-based nanomaterial with excellent performance. These characteristics make them have broad application potential in many fields.
[0003] Among them, single-walled carbon nanotubes (SWCNTs) are formed by winding a single layer of graphite sheet, have a cylindrical tubular structure, and are widely used in conductive materials, electromagnetic and microwave absorption, high-strength composites, fibers, sensors, field emission displays, inks, energy storage and conversion devices, radiation sources, and nanomanufacturing.
[0004] At present, the main methods for preparing carbon nanotubes include arc discharge method, laser ablation method and chemical vapor deposition method (CVD). Among them, the CVD method is widely used in the batch production of carbon nanotubes due to its lower reaction temperature, lower cost, higher purity and relatively higher product yield, and shows good industrialization prospects. The common forms of CVD reactor include horizontal and vertical types. In the horizontal fixed bed reactor, the diffusion of carbon source gas to the catalyst particles is the main factor restricting the reaction rate, and as the nanotubes grow, the catalyst surface is gradually covered, further reducing the contact between the carbon source and the catalyst. In contrast, the fluidized bed chemical vapor deposition method (FB-CVD) suspends the catalyst particles by upward flowing gas, thereby significantly improving the heat and mass transfer performance and increasing the contact area between the reactants and the catalyst. This method can effectively improve the chemical reaction and heat transfer efficiency, and is therefore considered as the most promising technical solution for batch production of SWCNTs.
[0005] However, the current research on the preparation of carbon nanotubes based on the FB-CVD technology mainly focuses on few-walled or multi-walled carbon nanotubes, and the research on single-walled carbon nanotubes is relatively less, and it is more technically challenging to prepare SWCNT with single chirality. Domestic and foreign scholars have carried out a large number of researches on the preparation of carbon nanotubes by FB-CVD technology, and developed different catalyst preparation methods. For example, the team of Suguru Noda in Japan adopts a spray deposition method to deposit metal nitrate on the surface of fluidizable zirconium dioxide beads to form a nanoscale catalyst film; Professor Wei Fei of Tsinghua University proposed a powder cluster fluidization theory, and successfully realized the industrialized preparation of few-walled or multi-walled carbon nanotubes.
[0006] In the traditional CVD method, the active centers of the catalyst for the growth of SWCNT are usually metal particles with a diameter of 1-10 nm, which are dispersed on a high specific surface area inert carrier (such as alumina, magnesium oxide or silicon dioxide) to promote the nucleation and growth of SWCNT. However, the traditional catalyst preparation method needs to use a large amount of solvent to dissolve the metal, and through processes such as drying and annealing, a catalyst powder with uniform metal distribution and small size is prepared. However, this method has problems such as high cost, easy agglomeration of metal particles and poor performance stability in batch production, and is mostly at the laboratory research and development stage. In addition, the traditional powder catalyst belongs to C-type particles, which are difficult to fluidize due to their strong cohesion, thereby limiting their application in the continuous preparation process of FB-CVD.
[0007] Therefore, there is a need for a continuous preparation device for chiral-enriched single-walled carbon nanotubes that can solve the above problems. Invention content
[0008] In order to solve the problems of the prior art, the present application provides a fluidized bed for continuously preparing chiral-enriched single-walled carbon nanotubes, which can continuously prepare chiral-enriched single-walled carbon nanotubes and has low cost and stable performance.
[0009] The technical effects achieved by the present application are realized by the following scheme:
[0010] According to the first aspect of the present application, a fluidized bed for continuously preparing chiral-enriched single-walled carbon nanotubes is provided, which comprises a main reactor, a catalyst pretreatment reactor and a cooling separator, the catalyst pretreatment reactor is coupled to the top of the main reactor, the bottom of the main reactor is provided with a first gas inlet, and the cooling separator is connected to the top of the main reactor through a gas flow conveying pipe.
[0011] Preferably, the catalyst pretreatment reactor is externally provided with a second heating device.
[0012] Preferably, the bottom of the catalyst pretreatment reactor is provided with a second gas inlet, the top is provided with a second gas outlet and a catalyst charging port.
[0013] Preferably, the main reactor is a tubular structure, and the outer periphery of the main reactor is provided with a first heating device,
[0014] Preferably, the main reactor is sequentially provided with a catalyst loading area, a settling section and a cyclone separator from bottom to top, and the top of the main reactor is provided with a first gas outlet.
[0015] Preferably, a gas distribution plate is arranged below the catalyst loading area for uniform distribution of the reaction gas entering from the bottom.
[0016] Preferably, the settling section is an enlarged cavity structure for reducing the gas flow rate to achieve gas-solid separation.
[0017] Preferably, the bottom of the cooling separator is provided with a discharge port, the side wall is provided with a third gas inlet connected to the gas flow conveying pipe, and the top is provided with a third gas outlet.
[0018] Preferably, a filter is arranged in the cooling separator, and the third gas outlet is connected to the cavity of the cooling separator through the filter.
[0019] According to one embodiment of the present application, the beneficial effects of the continuous preparation of the fluidized bed of chiral-enriched single-walled carbon nanotubes are that the device is reasonably designed, and through the synergistic effect of the catalyst pretreatment reactor, the main reactor and the cooling separator, the continuous preparation of carbon nanotubes can be realized, and the preparation cost is relatively low, and the performance is stable and reliable. BRIEF DESCRIPTION OF DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.
[0021] Figure 1 The structure diagram of a fluidized bed for continuously preparing chiral-enriched single-walled carbon nanotubes in an embodiment of the present application. DETAILED DESCRIPTION
[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0023] like Figure 1 As shown, a fluidized bed for the continuous preparation of chiral enriched single-walled carbon nanotubes in one embodiment of this application includes a main reactor 1, a catalyst pretreatment reactor 2, and a cooling separator 3. The catalyst pretreatment reactor 2 is coupled to the top of the main reactor 1. A first heating device 18 is provided outside the main reactor 1, and a second heating device 17 is provided outside the catalyst pretreatment reactor 2 for heating the catalyst and reaction gas inside the reactor to maintain a constant reaction temperature. The cooling separator 3 is connected to the top of the main reactor 1 through a gas flow pipe 10.
[0024] The catalyst pretreatment reactor 2 is mainly used for calcination and reduction of the catalyst. It is equipped with a second air inlet 15 at the bottom, a second air outlet 16 at the top, and a catalyst feed port 19 to allow the introduction of reducing gas or inert gas for treatment. The treated catalyst is introduced into the main reactor 1 through pipelines via the difference in elevation and pressure. After the catalyst pretreatment reactor 2 is empty, it can continue to process the next batch of catalyst, ensuring the continuity of production.
[0025] The first heating device 18 and the second heating device 17 are, for example, electromagnetic heaters, capable of controlling the heating temperature and heating time as needed.
[0026] The main reactor 1 is a tubular structure. The bottom of the main reactor 1 is provided with a first air inlet 8. From bottom to top, the main reactor 1 is provided with a catalyst loading zone 5, a settling section 6 and a cyclone separator 7. The top of the main reactor 1 is provided with a first air outlet 9.
[0027] To improve the uniformity of the reaction, a gas distribution plate 4 is provided below the catalyst loading zone 5 to disperse the reaction gas entering from the bottom, ensuring that it enters the catalyst loading zone 5 evenly. The gas distribution plate 4 has several through holes evenly arranged on it; for example, the gas distribution plate 4 has a honeycomb structure, which can evenly blow the gas flow from the bottom into the catalyst loading zone 5.
[0028] After the reaction gas passes through the gas distribution plate 4 and comes into contact with the catalyst at the bottom, the catalyst particles are fluidized under the action of the gas flow. During the reaction, the carbon source gas undergoes high-temperature pyrolysis and deposition at the active center of the catalyst, growing to form single-walled carbon nanotubes.
[0029] The settling section 6 is an enlarged cavity structure, where the gas velocity is significantly reduced, realizing gas-solid separation, and the catalyst solid is stabilized in the catalyst loading section 5 to be fluidized, and the reaction tail gas is discharged from the first gas outlet 9 after being purified by the cyclone separator 7. The cyclone separator 7 separates the carbon nanotubes from other particles in the gas stream by centrifugal force, ensuring high purity of the carbon nanotubes.
[0030] In an embodiment of the present application, when the growth of carbon nanotubes is completed, the reaction products and catalyst are transported together to the cooling separator 3 by increasing the gas velocity of the carrier gas. The cooling separator 3 is provided with a discharge port 11 at the bottom, a third gas inlet 12 connected to the gas flow conveying pipe 10 on the side wall, and a third gas outlet 14 at the top.
[0031] A filter 13 is provided in the cooling separator 3, and the third gas outlet 14 is connected to the cavity of the cooling separator 3 through the filter 13, which prevents the carbon nanotube product from being blown out by the gas flow. The filter 13 is, for example, one of a ceramic filter, a metal filter, a polymer membrane filter, a fiber filter, and a nano-porous material filter.
[0032] The cooling separator 3 is used for cooling and separating the product. Under the protection of inert gas, the catalyst and carbon nanotube product are cooled to room temperature and then discharged through the discharge port 11, and the product can be directly collected.
[0033] Valves are provided between the main reactor 1, the catalyst pretreatment reactor 2, and the cooling separator 3 in this embodiment to facilitate the opening and closing of different stages of the reaction; solenoid valves are also provided on the first gas inlet 8, the first gas outlet 9, the second gas inlet 15, the second gas outlet 16, the third gas inlet 12, and the third gas outlet 14, which can be opened and closed by a control system.
[0034] In actual use of the fluidized bed, the prepared catalyst is placed in the catalyst pretreatment reactor 2 and reduced gas is introduced to remove oxides on the surface of the catalyst and activate the active centers of the catalyst. The reducing gas is a reducing gas selected from hydrogen or carbon monoxide, preferably hydrogen, and the reduction temperature is 400-800 degrees, and the reduction time is 10-120 minutes.
[0035] The reduced catalyst is introduced into the main reactor 1 for the growth of carbon nanotubes. In the main reactor 1, the temperature is controlled in the range of 600-1200°C, and carbon source gas and carrier gas are introduced from the first gas inlet 8 of the main reactor 1. The carbon source gas is one or more of CO, CH4, CH3CH2OH, CH3OH, C2H4, C2H2, and C2H6. The carbon source gas is cracked at the active centers of the catalyst, carbon atoms are deposited on the surface of the catalyst, and then single-walled carbon nanotubes are formed.
[0036] When the carbon tube growth reaches a predetermined time, the reaction product (including carbon nanotubes and catalyst particles) is blown out of the main reactor 1 by increasing the flow rate of the carrier gas and is transported to the cooling separator 3 by the gas flow.
[0037] In the cooling separator 3, the reaction product is cooled to room temperature, and finally the recovery of the chiral single-walled carbon nanotube product is achieved. During the cooling process, the inert gas is used to protect the structural stability of the carbon nanotubes.
[0038] According to one embodiment of the present application, the fluidized bed for continuously preparing chiral-enriched single-walled carbon nanotubes has the beneficial effects that the device is rationally designed, and through the synergistic effect of the catalyst pretreatment reactor, the main reactor and the cooling separator, the continuous preparation of carbon nanotubes can be achieved, and the preparation cost is relatively low, and the performance is stable and reliable.
[0039] It should be noted that the above detailed description is exemplary and is intended to provide further explanation of the present 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 the present application belongs.
[0040] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise. In addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they refer to the presence of a feature, step, operation, device, component and / or combinations thereof.
[0041] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0042] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0043] For purposes of the description hereinafter, spatial
[0044] In the detailed description above, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments can be used, and other changes can be made, without departing from the spirit or scope of the subject matter presented herein.
[0045] The preferred embodiments of the present application have been described above with the aid of drawing only by way of example and are not limiting of the present application. Various modifications and alterations of the present application are possible and are encompassed by the scope of the present application disclosed herein, which is not to be limited by the appended claims unless otherwise indicated.
Claims
1. A fluidized bed for continuously producing chiral-enriched single-wall carbon nanotubes, characterized by, The application relates to a catalyst pre-treatment reactor and a cooling separator, which are connected to the top of a main reactor, the bottom of the main reactor is provided with a first gas inlet, and the cooling separator is connected to the top of the main reactor through a gas flow conveying pipe.
2. The fluidized bed for continuously producing chiral-enriched single-wall carbon nanotubes according to claim 1, wherein The catalyst pre-treatment reactor is externally provided with a second heating device.
3. The fluidized bed for continuously producing chiral-enriched single-walled carbon nanotubes according to claim 2, wherein The bottom of the catalyst pre-treatment reactor is provided with a second gas inlet, the top is provided with a second gas outlet and a catalyst feeding port.
4. The fluidized bed for continuously producing chiral-enriched single-wall carbon nanotubes according to claim 1, wherein The main reactor is in a tubular structure, and the periphery of the main reactor is provided with a first heating device.
5. The fluidized bed for continuously producing chiral-enriched single-walled carbon nanotubes according to claim 4, wherein The main reactor is sequentially provided with a catalyst loading area, a settling section and a cyclone separator from bottom to top, and the top of the main reactor is provided with a first gas outlet.
6. The fluidized bed for continuously producing a chiral -enriched single-walled carbon nanotube according to claim 5, wherein The catalyst loading area is provided with a gas distribution plate below the catalyst loading area, which is used for uniformly distributing the reaction gas entering from the bottom.
7. The fluidized bed for continuously producing chiral-enriched single-walled carbon nanotubes according to claim 5, wherein The settling section is in an expanded cavity structure, which is used for reducing the gas flow rate to realize gas-solid separation.
8. The fluidized bed for continuously producing chiral -enriched single-wall carbon nanotubes according to claim 1, wherein The bottom of the cooling separator is provided with a discharge port, the sidewall is provided with a third gas inlet connected with the gas flow conveying pipe, and the top is provided with a third gas outlet.
9. The fluidized bed for continuously producing a chiral-enriched single-wall carbon nanotube according to claim 8, wherein The cooling separator is provided with a filter, and the third gas outlet is communicated into the cavity of the cooling separator through the filter.