Regenerated carbon fiber adsorption felt and preparation method thereof
Through technical means to control high-temperature cracking and aerobic combustion, the problems of poor adsorption capacity and high recovery cost of conventional regenerated carbon fibers are solved, and regenerated carbon fiber felts with high adsorption capacity and stability are achieved.
Patent Information
- Application Number
- CN202411934016.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-03-18
AI Technical Summary
Due to the pyrolysis and recovery method, conventional recycled carbon fibers have many residual impurities on the surface and poor adsorption capacity, and high solvent treatment cost and poor environmental protection.
By controlling the high temperature to crack the residual resin and burn it oxygenically, residual impurities are removed and surfactant groups are increased, and the adsorption amount is increased. Specific steps include crushing the carbon fiber composite material, performing hypoxia preheating, pyrolysis, low temperature treatment, carbon attachment and oxidation treatment.
The adsorption capacity and stability of the regenerated carbon fiber felt are significantly improved, and good adsorption performance for organic matter and inorganic gases are achieved.
Smart Images
Figure BDA0005211049370000061
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of regenerated carbon fiber, and in particular to a regenerated carbon fiber adsorption felt and a preparation method thereof. Background Art
[0002] Adsorption refers to the enrichment or loss of one or more components at an interface. Adsorption is a common physical and chemical phenomenon. The principle of adsorption is that the molecules or atoms on the surface of a solid form residual surface energy due to uneven forces. Therefore, when other substances collide with the surface of the solid, these surface energies attract the substances through force and make them stay on the solid surface. The solid mentioned here is defined as an adsorbent, and the substance adsorbed by it is defined as an adsorbate. Through adsorption, the adsorbate is concentrated on the adsorbent, and this process reduces the surface energy of the adsorbent.
[0003] Activated carbon fiber adsorption material is an adsorption material with a highly developed microporous structure made from organic fiber directly through carbonization and activation. Compared with activated carbon, it has a larger specific surface area (up to 1000m 2 / g or more), uniform pore size, high adsorption capacity, fast adsorption and desorption speed, easy desorption, etc. Therefore, under the same treatment capacity, the amount of activated carbon fiber required is only a few tens of the amount of granular activated carbon. Because of this, although the price of carbon fiber is very high at present, it still has certain practical applications in waste gas treatment (especially solvent recovery from organic waste gas) and organic wastewater treatment. With the gradual reduction of its production cost, the application of activated carbon fiber in environmental protection will have broad application prospects.
[0004] Conventional recycled carbon fiber is mostly recycled in the form of pyrolysis. After burning, a lot of inorganic dust remains on the surface of the carbon fiber, and the surface is irregularly round, resulting in poorer adsorption capacity than conventional activated carbon fiber. The recycled carbon fiber obtained by conventional solvent treatment has high recycling costs, and it is difficult to reuse the solvent, making it difficult to achieve an environmentally friendly recycling method. Summary of the invention
[0005] The present invention provides a regenerated carbon fiber adsorption felt and a preparation method thereof. By controlling the residual resin through high-temperature cracking and then aerobically burning the residual resin, the residual impurities can be effectively removed while effectively increasing the surface active groups and improving the adsorption capacity.
[0006] In one aspect, the present invention provides a method for preparing a regenerated carbon fiber adsorption felt, comprising the following steps:
[0007] S1. Crushing the carbon fiber composite material into blocks of 5-10 cm in size;
[0008] S2: Add the carbon fiber crushed material into the feeding section, and continuously introduce nitrogen at room temperature into the feeding section to maintain a low oxygen state;
[0009] S3: The carbon fiber crushed material enters the preheating section along with the conveying equipment, and high-temperature nitrogen is continuously introduced into the preheating section;
[0010] S4: The carbon fiber crushed material enters the pyrolysis section along with the conveying equipment, and high-temperature nitrogen is continuously introduced into the pyrolysis section; a large amount of hydrocarbon gas is generated and extracted to the processing network, and pure hydrocarbons are obtained through refining and separation processing steps;
[0011] S5: The carbon fiber crushed material enters the low temperature section along with the conveying equipment, and the low temperature section is continuously introduced with normal temperature air and atomized coupling agent aqueous solution;
[0012] S6: The carbon fiber crushed material enters the carbon attachment section along with the conveying equipment. The pure hydrocarbon will be heated to a higher temperature and pyrolyzed in an oxygen-free or low-oxygen environment to generate carbon black and blown back into the carbon attachment section to form a carbon layer on the surface of the low-temperature fiber.
[0013] S7: The carbon fiber crushed material enters the oxidation section along with the conveying equipment, and high-temperature oxygen is continuously introduced. The carbon layer is sintered on the fiber surface to form a porous structure.
[0014] In certain embodiments, the nitrogen gas flow rate in step S1 is 0.1-10 m 3 / min; the residence time in the feeding section is 5-15min.
[0015] In certain embodiments, the temperature in step S2 is 200-400°C and the nitrogen flow rate is 1-10m 3 / min; the residence time in the preheating section is 15-30min.
[0016] In certain embodiments, the temperature in step S3 is 600-800°C and the nitrogen flow rate is 1-10m 3 / min; the residence time in the pyrolysis stage is 1-2h.
[0017] In certain embodiments, the air flow rate in step S4 is 1-10 m 3 / min; the residence time in the low temperature section is 15-30min.
[0018] In certain embodiments, the air intake in step S5 is 1-10 m 3 / min; the residence time in the low temperature section is 15-30min.
[0019] In certain embodiments, the oxygen feed rate in step S7 is 1-10 m 3 / min, temperature is 400-600℃, and residence time is 10-20min.
[0020] On the other hand, the present invention provides a regenerated carbon fiber adsorption felt, which is prepared by the following preparation method:
[0021] S1. Crushing the carbon fiber composite material into blocks of 5-10 cm in size;
[0022] S2: Add the carbon fiber crushed material into the feeding section, and continuously introduce nitrogen at room temperature into the feeding section to maintain a low oxygen state;
[0023] S3: The carbon fiber crushed material enters the preheating section along with the conveying equipment, and high-temperature nitrogen is continuously introduced into the preheating section;
[0024] S4: The carbon fiber crushed material enters the pyrolysis section along with the conveying equipment, and high-temperature nitrogen is continuously introduced into the pyrolysis section; a large amount of hydrocarbon gas is generated and extracted to the processing network, and pure hydrocarbons are obtained through refining and separation processing steps;
[0025] S5: The carbon fiber crushed material enters the low temperature section along with the conveying equipment, and the low temperature section is continuously introduced with normal temperature air and atomized coupling agent aqueous solution;
[0026] S6: The carbon fiber crushed material enters the carbon attachment section along with the conveying equipment. The pure hydrocarbon will be heated to a higher temperature and pyrolyzed in an oxygen-free or low-oxygen environment to generate carbon black and blown back into the carbon attachment section to form a carbon layer on the surface of the low-temperature fiber.
[0027] S7: The carbon fiber crushed material enters the oxidation section along with the conveying equipment, and high-temperature oxygen is continuously introduced. The carbon layer is sintered on the fiber surface to form a porous structure.
[0028] The regenerated carbon fiber adsorption felt of the present invention has the following beneficial effects:
[0029] 1. High adsorption capacity: The surface treatment increases the active groups and adsorption capacity of the carbon fiber surface, so that the recycled carbon fiber felt has good adsorption performance for organic matter, inorganic gases, etc.
[0030] 2. Higher stability: Since carbon fiber and carbon black are oxidized, the bonding effect is effectively improved and the stability is improved.
[0031] In summary, the preparation of carbon fiber composite materials into non-deformable and highly adsorbent recycled carbon fiber felt by pyrolysis recycling is a complex and delicate process. In this process, the conditions and parameters of each link need to be strictly controlled to ensure the quality and performance of the final product. DETAILED DESCRIPTION
[0032] The present invention is further described in detail below through embodiments.
[0033] Example 1
[0034] Materials preparation:
[0035] Waste carbon fiber composite materials are selected as raw materials to ensure that they are free of obvious metal impurities and large amounts of pollutants.
[0036] step:
[0037] 1. Crushing: Use a mechanical crusher to crush the carbon fiber composite material into blocks of 5-10 cm in size.
[0038] 2. Feeding section processing: The crushed carbon fiber blocks are added to the feeding section of the continuous pyrolysis line. This section is continuously fed with room temperature nitrogen, and the nitrogen intake is controlled at 0.5m 3 / min, maintain hypoxia state. The residence time is 10min.
[0039] 3. Preheating treatment: The crushed material enters the preheating section, where high-temperature nitrogen at 300°C is continuously introduced, with a nitrogen flow rate of 5m 3 / min. The residence time is 20min.
[0040] 4. Pyrolysis treatment: The preheated crushed material enters the pyrolysis section, where high-temperature nitrogen at 700°C is continuously introduced at a rate of 5m 3 / min. The residence time is 1.5h. The generated hydrocarbon gas is extracted and subjected to refining and separation treatment.
[0041] 5. Low temperature section treatment: The crushed material after pyrolysis enters the low temperature section, where room temperature air and atomized coupling agent aqueous solution are continuously introduced. The air intake is 5m 3 / min. The residence time is 20min.
[0042] 6.Carbon attachment section treatment: The crushed material after low temperature section treatment enters the carbon attachment section, where pure hydrocarbons are heated to a higher temperature in an oxygen-free environment to generate carbon black which is then blown back into the carbon attachment section to form a carbon layer on the surface of the low temperature fiber.
[0043] 7. Oxidation stage treatment: Finally, the crushed material enters the oxidation stage, where high-temperature oxygen with a temperature of 500°C is continuously introduced, and the oxygen introduction rate is 5m 3 / min. The residence time is 15min, and the carbon layer is sintered on the fiber surface to form a porous structure.
[0044] Product Features:
[0045] After the above treatment, the obtained recycled carbon fiber felt has high adsorption capacity and high stability, and has good adsorption performance for organic matter and inorganic gases.
[0046] Example 2
[0047] Materials preparation:
[0048] Another type of carbon fiber composite material is selected as raw material, ensuring that its composition and structure are different from those in Example 1.
[0049] step:
[0050] Similar to Example 1, but with different specific parameters:
[0051] 1. Crushing: Crushing the carbon fiber composite material into blocks of 7-8cm in size.
[0052] 2. Feeding section treatment: nitrogen intake is controlled at 2m 3 / min, and the residence time is 8min.
[0053] 3. Preheating treatment: nitrogen flow rate is 3m 3 / min, temperature is 250℃ and residence time is 25min.
[0054] 4. Pyrolysis treatment: nitrogen flow rate is 3m 3 / min, temperature is 650℃ and residence time is 1.2h.
[0055] 5. Low temperature treatment: air intake is 3m 3 / min, and the residence time is 25min.
[0056] 6. Carbon attachment treatment: Use different coupling agent aqueous solutions and make corresponding adjustments.
[0057] 7. Oxidation stage treatment: oxygen intake is 3m 3 / min, the temperature is 450℃ and the residence time is 12min.
[0058] Product Features:
[0059] The obtained recycled carbon fiber felt also has high adsorption capacity and high stability, but its specific adsorption performance and stability may vary depending on the raw materials and parameters.
[0060] Comparative Example 1
[0061] Materials preparation:
[0062] The same carbon fiber composite material as in Example 1 was selected as the raw material.
[0063] step:
[0064] 1. Crushing: Crushing carbon fiber composite materials into blocks of 5-10cm in size.
[0065] 2. Conventional pyrolysis treatment: The crushed carbon fiber blocks are directly subjected to conventional pyrolysis treatment without any special treatment in the feeding section, preheating section, low temperature section, carbon attachment section and oxidation section.
[0066] Product Features:
[0067] The surface adsorption capacity of the obtained recycled carbon fiber felt is poor and the stability is low.
[0068] Comparative Example 2
[0069] Materials preparation:
[0070] The same carbon fiber composite material as in Example 2 was selected as the raw material.
[0071] step:
[0072] 1. Crushing: Crushing the carbon fiber composite material into blocks of 7-8cm in size.
[0073] 2. Conventional solvent treatment: The crushed carbon fiber blocks are recycled using conventional solvent methods.
[0074] 3. Carry out conventional oxidation treatment, the oxygen flow rate is 3m 3 / min, the temperature is 450℃ and the residence time is 12min.
[0075] Product Features:
[0076] Although the surface of the obtained regenerated carbon fiber felt is relatively clean, the recycling cost is high, the solvent reuse is difficult, and the adsorption capacity is not as good as the regenerated carbon fiber felt in the embodiment.
[0077] Summarize
[0078] By comparing the examples and comparative examples, it can be seen that the recycled carbon fiber felt prepared by the method proposed in this patent has significantly high adsorption capacity and high stability. Conventional pyrolysis treatment and solvent treatment cannot achieve such excellent performance. Therefore, the method proposed in this patent has broad application prospects in the field of carbon fiber recycling.
[0079] Comparison of nitrogen adsorption performance
[0080]
[0081] Summary and Analysis
[0082] By comparing the experimental results of Example 1, Example 2, and Comparative Examples 1 and 2, we can draw the following conclusions:
[0083] 1. Adsorption performance and specific surface area:
[0084] The specific surface area of the regenerated carbon fiber felt of Example 1 is 2721m 2 / g, the specific surface area of Example 2 is 2210m 2 / g, which is much higher than 872m / g in Comparative Example 1. 2 / g and 1150m 2 / g. Specific surface area is one of the important indicators for measuring the adsorption performance of adsorbent materials. The larger the specific surface area, the more adsorption sites there are and the stronger the adsorption capacity. Therefore, the regenerated carbon fiber felts of Examples 1 and 2 have higher adsorption capacity.
[0085] 2. Impact of treatment process:
[0086] Examples 1 and 2 adopt the continuous pyrolysis production line recovery method proposed in this patent, including multiple processing steps such as feeding section, preheating section, pyrolysis section, low temperature section, carbon attachment section and oxidation section. These steps act together on the carbon fiber composite material, effectively removing residual impurities, increasing the surface active groups, and improving the adsorption capacity.
[0087] Comparative Example 1 was subjected to only conventional pyrolysis treatment without other special treatments, resulting in poor adsorption capacity and low stability on the surface of the regenerated carbon fiber felt.
[0088] Although the comparative example 2 adopts the conventional solvent method and performs the conventional oxidation treatment, the recovery cost is high, the solvent reuse is difficult, and the adsorption capacity is not as good as the regenerated carbon fiber felt in the embodiment. This may be due to the introduction of new impurities during the solvent method treatment, or the failure to effectively increase the active groups on the carbon fiber surface.
[0089] 3. Influence of raw materials and parameters:
[0090] Although the same treatment process was used in Example 1 and Example 2, the raw materials and specific parameters were different, resulting in differences in the specific surface area and adsorption performance of the final product. This indicates that the composition and structure of the raw materials, as well as parameters such as temperature, time, and gas flow rate during the treatment process, will affect the performance of the final product.
[0091] In summary, the recycled carbon fiber felt prepared by the continuous pyrolysis production line recycling method proposed in this patent has significantly high adsorption capacity and high stability, which is superior to conventional pyrolysis treatment and solvent treatment. This method has broad application prospects in the field of carbon fiber recycling and provides a new way for the environmentally friendly recycling and reuse of carbon fiber.
[0092] The above description is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, and these should also be regarded as within the scope of protection of the invention.
Claims
1. A method for preparing a regenerated carbon fiber adsorption felt, characterized in that: The following steps are involved: S1. Crushing the carbon fiber composite material into blocks of 5-10 cm in size; S2: Add the carbon fiber crushed material into the feeding section, and continuously introduce nitrogen at room temperature into the feeding section to maintain a low oxygen state; S3: The carbon fiber crushed material enters the preheating section along with the conveying equipment, and high-temperature nitrogen is continuously introduced into the preheating section; S4: The carbon fiber crushed material enters the pyrolysis section along with the conveying equipment, and high-temperature nitrogen is continuously introduced into the pyrolysis section; a large amount of hydrocarbon gas is generated and extracted to the processing network, and pure hydrocarbons are obtained through refining and separation processing steps; S5: The carbon fiber crushed material enters the low temperature section along with the conveying equipment, and the low temperature section is continuously introduced with normal temperature air and atomized coupling agent aqueous solution; S6: The carbon fiber crushed material enters the carbon attachment section along with the conveying equipment. The pure hydrocarbon will be heated to a higher temperature and pyrolyzed in an oxygen-free or low-oxygen environment to generate carbon black and blown back into the carbon attachment section to form a carbon layer on the surface of the low-temperature fiber. S7: The carbon fiber crushed material enters the oxidation section along with the conveying equipment, and high-temperature oxygen is continuously introduced. The carbon layer is sintered on the fiber surface to form a porous structure.
2. The method for preparing a regenerated carbon fiber adsorption felt according to claim 1, characterized in that: The nitrogen flow rate in step S1 is 0.1-10m 3 / min; the residence time in the feeding section is 5-15min.
3. The method for preparing a regenerated carbon fiber adsorption felt according to claim 1, characterized in that: In step S2, the temperature is 200-400°C and the nitrogen flow rate is 1-10m 3 / min; the residence time in the preheating section is 15-30min.
4. The method for preparing a regenerated carbon fiber adsorption felt according to claim 1, characterized in that: In step S3, the temperature is 600-800°C and the nitrogen flow rate is 1-10m 3 / min; the residence time in the pyrolysis stage is 1-2h.
5. The method for preparing a regenerated carbon fiber adsorption felt according to claim 1, characterized in that: The air intake in step S4 is 1-10m 3 / min; the residence time in the low temperature section is 15-30min.
6. The method for preparing a regenerated carbon fiber adsorption felt according to claim 1, characterized in that: The air intake in step S5 is 1-10m 3 / min; the residence time in the low temperature section is 15-30min.
7. The method for preparing a regenerated carbon fiber adsorption felt according to claim 1, characterized in that: The oxygen flow rate in step S7 is 1-10m 3 / min, temperature is 400-600℃, and residence time is 10-20min.
8. Regenerated carbon fiber adsorption felt prepared by the preparation method according to any one of claims 1 to 7.