阅读说明：本技术 一种活性炭纤维毡及其制备方法和应用 (Activated carbon fiber felt and preparation method and application thereof ) 是由 曹伟伟 朱波 乔琨 于丽媛 虞军伟 于 2019-08-01 设计创作，主要内容包括：本发明提供一种活性炭纤维毡及其制备方法和应用,该活性炭纤维毡为碳化的纤维毡,所述碳纤维毡包括至少两层网胎,网胎之间交替叠层,和在网胎交替叠层间针刺贯穿以连接固定相邻叠层的针刺纤维；所述活性炭纤维毡的表面孔径为不高于0.7nm。本发明的活性炭纤维毡表面具有特定孔径尺度的多孔结构,可达到有效吸附氢气作用。(The invention provides an activated carbon fiber felt and a preparation method and application thereof, the activated carbon fiber felt is a carbonized fiber felt, the carbon fiber felt comprises at least two layers of net tires, the net tires are alternately laminated, and needling is penetrated between the alternately laminated net tires to connect and fix needling fibers of adjacent laminated layers; the surface aperture of the activated carbon fiber felt is not higher than 0.7 nm. The surface of the activated carbon fiber felt has a porous structure with a specific pore size, so that the activated carbon fiber felt can effectively adsorb hydrogen.)

1. An activated carbon fiber felt is an activated carbon fiber felt, and comprises at least two layers of net tires, wherein the net tires are alternately laminated, and needling is performed between the net tires alternately laminated to connect and fix needling fibers of adjacent laminated layers; the surface aperture of the activated carbon fiber felt is not higher than 0.7 nm.

2. The activated carbon fiber mat according to claim 1, wherein the surface pore size of the activated carbon fiber mat is not higher than 0.65nm, or not higher than 0.6nm, or 0.6-0.7 nm;

preferably, the mesh is made of pre-oxidized fibers;

preferably, the tensile strength of the pre-oxidized fiber is not lower than 200MPa, the tensile modulus is not lower than 1.0GPa, and the density of the fiber body is not lower than 1.3g/cm³The carbon content of the fiber is not less than 65 wt%.

3. The activated carbon fiber mat according to claim 2, wherein the pre-oxidized fibers are polyacrylonitrile pre-oxidized fibers and/or viscose-based pre-oxidized fibers.

4. The activated carbon fiber mat according to claim 1, wherein the single ply batt has a grammage of 10-50g/m²。

5. The activated carbon fiber mat of claim 1, wherein the needled fibers are needled through the stacked web in a direction perpendicular to the plane of lamination.

6. A method for preparing the activated carbon fiber mat of any one of claims 1 to 5, comprising carding pre-oxidized fibers, which are used as raw materials, into a web body by a carding process; the net body is laminated through a lamination process, the lamination is carried out by needling the needling fiber to obtain the carbon fiber felt, and the carbon fiber felt is carbonized and cooled to obtain the activated carbon fiber felt.

7. The method of claim 6 wherein the needling is performed in a direction perpendicular to the lamination plane;

preferably, the needling density is 10-40 needles/cm²。

8. The method as claimed in claim 6, wherein the carbonization treatment comprises heating to 1000-1500 ℃ and introducing steam to carbonize the carbon fiber felt;

preferably, the heating rate is 5-15 ℃/min;

preferably, the rate of introducing the water vapor is 3 to 15 g/min;

preferably, the carbonization time is 20-50 min;

preferably, the carbonization is performed under a nitrogen atmosphere.

9. The method as claimed in claim 6, wherein the carbonization is completed and then cooled to 150 ℃ and 200 ℃ in a nitrogen atmosphere; then naturally cooling to room temperature.

10. Use of the activated carbon fiber mat of any one of claims 1 to 5 in the field of hydrogen energy storage and/or adsorption.

Technical Field

The invention relates to the field of carbonaceous materials for hydrogen storage, and particularly relates to an activated carbon fiber felt and a preparation method and application thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

Solid material hydrogen storage is widely favored by researchers due to the characteristics of high safety, low energy consumption and the like. The solid hydrogen storage materials researched and developed at present mainly comprise metal alloy materials, carbonaceous materials, inorganic porous materials, composite chemical hydrogen compound materials, metal organic framework compound materials and the like. The elastic finger material has the advantages of large hydrogen absorption amount, light weight, strong anti-poisoning performance, easy desorption and the like, and the physical adsorption hydrogen storage is considered to be a hydrogen storage mode with great application prospect. Among the more promising carbon-absorbing materials for hydrogen storage are activated carbon fiber felt, carbon nanofibers and carbon nanotubes.

The inventors have found that carbon nanofiber hydrogen storage, despite large hydrogen storage volumes, is costly in hydrogen storage media, slow in desorption rates, short in cycle life, and unsuitable for large-scale storage and transportation. The research on carbon nanotube hydrogen storage is popular, but the results obtained by various researchers are quite different, researchers in the national renewable energy laboratory in the united states begin to research carbon nanotube hydrogen storage earlier, Chambers and the like find that the hydrogen storage amounts of graphite nanofibers with herringbone shapes and plate shapes at the room temperature of 120MPa reach 67% and 53%, respectively, but Gary G and the like measure the hydrogen storage performances of 9 different carbon nanotube materials at the room temperature of-80 to 500 ℃ under 11MPa, and indicate that any report about that the carbon nanotube materials store more than 1% of hydrogen at the room temperature is unreliable. In order to confirm the best hydrogen storage capacity of the carbon nano tube, a series of experiments are carried out on the whole theory, and the result shows that the maximum hydrogen storage capacity of the carbon nano tube at normal temperature is not more than 0.5 percent, so that the hydrogen storage application prospect of the carbon nano tube is not very optimistic.

Disclosure of Invention

The inventor finds that the activated carbon fiber felt is a good carbon adsorbent all the time, and particularly the activated adsorption performance of the modified activated carbon fiber felt is greatly improved. Especially for the adsorption and hydrogen storage of the activated carbon fiber felt material with controllable surface pore structure characteristics, the method has the advantages of economy, high hydrogen storage capacity, quick desorption, long cycle service life, easy realization of large-scale production and the like. Based on the technical scheme, the invention provides an activated carbon fiber felt for hydrogen energy absorption and storage, and a preparation method and application thereof.

The active carbon fiber felt prepared by the invention is of a porous structure with a specific pore size on the surface, and can effectively adsorb hydrogen, the pore size of the monofilament fiber on the surface of the active carbon fiber felt is controlled within the range of not more than 0.7nm, or not more than 0.65nm, or not more than 0.6nm, or 0.6-0.7nm, and finally the hydrogen absorption rate of the active carbon fiber felt is within the range of 2.5%, and the active carbon fiber felt can also realize the storage of the adsorbed hydrogen.

Specifically, the technical scheme of the invention is as follows:

in a first aspect of the invention, the invention provides an activated carbon fiber felt which is an activated carbon fiber felt comprising at least two layers of alternately laminated mesh bodies, and needled penetrating between the alternately laminated mesh bodies to connect and fix needled fibers of adjacent laminated layers; the density of the carbon fiber felt is 0.05-0.09g/m³The surface pore diameter of the activated carbon fiber felt is not higher than 0.7nm, or not higher than 0.65nm, or not higher than 0.6nm, or 0.6-0.7 nm.

The carbon fiber mats of the present invention are also referred to as pre-oxidized fiber mats in the summary and embodiments of the present invention, and the two may be used interchangeably in the present invention.

The net tyre of the invention takes pre-oxidized fiber as raw material. In some embodiments of the invention, the pre-oxidized fibers have a tensile strength of 200MPa or greater, a tensile modulus of 1.0GPa or greater, and a bulk density of 1.3g/cm³Above, carbon content of fiberNot less than 65 wt%.

In some embodiments of the invention, the pre-oxidized fibers are polyacrylonitrile pre-oxidized fibers and/or viscose-based pre-oxidized fibers.

In certain embodiments of the present invention, the single layer web structure of the carbon fiber mat of the present invention has a grammage of 10 to 50g/m²。

In an embodiment of the invention, the needled fibers are needled through the stacked web in a direction perpendicular to the plane of the stack (i.e., in the Z-axis direction).

In a second aspect of the present invention, the present invention provides a method for preparing the above activated carbon fiber mat, which comprises using pre-oxidized fibers as raw materials, carding the pre-oxidized fibers into a web body by a web carding process; the net body is laminated through a lamination process, the lamination is carried out by needling the needling fiber to obtain the carbon fiber felt, and the carbon fiber felt is carbonized, activated and cooled to obtain the activated carbon fiber felt.

Firstly, high-performance pre-oxidized fibers are used as raw materials, and a web tire is carded by adopting a carding process; then, the net tire is laminated by adopting a hybrid lamination process and needled into a felt, and the needling density in the thickness direction and the needling fiber hybrid proportion are controlled in the needling process; finally, the flow and the temperature of the activated medium in the activation process are controlled through the activation process so as to achieve the purpose of controlling the pore diameter of the monofilament fiber surface of the activated carbon fiber felt, and the activated carbon fiber felt material with controllable surface pore structure characteristics is prepared.

The pre-oxidized fiber raw material can be selected from polyacrylonitrile pre-oxidized fiber and/or viscose pre-oxidized fiber, the tensile strength of the pre-oxidized fiber is not less than 200MPa, such as 250-300MPa, the tensile modulus is not less than 1.0GPa, such as 1.2-2.0GPa, and the density of the fiber body is not less than 1.3g/cm³For example, 1.3 to 1.5g/cm³The carbon content of the fibers is not less than 65% by weight, for example, 55 to 75% by weight.

The carding process adopts the high-performance pre-oxidized fiber as a raw material to carry out the carding treatment, and the carding process ensures that the gram weight of a single-layer net tire is 10-50g/m²In the range of further 10 to 45g/m²E.g. 10g/m²、40g/m²Or 45g/m². When different types of fiber hybrid carded webs are adopted, the carded web mixing proportion can be flexibly adjusted according to requirements, for example, when different pre-oxidized fiber hybrid carded webs are used, for example, polyacrylonitrile pre-oxidized fibers and viscose-based pre-oxidized fibers are mixed, the mixing proportion (mass ratio) can be flexibly adjusted, for example, the mixing proportion is 1: 1-99 or 1-99: 1, e.g. 1: 1. 1: 5 or 4: 1.

the mesh tire hybrid lamination can adopt mesh tires with different gram weights to be mixed so as to adjust the density gradient of fibers in different layers. The lamination needling is performed in the direction perpendicular to the lamination surface (i.e. along the Z-axis direction), and the needling density is controlled to be 10-40 needles/cm²Within the range, the needle punched fibers are selected from pre-oxidized fibers, the needle punched fibers can be mixed of different pre-oxidized fibers, and the mixing ratio can be flexibly adjusted. For example, the needle-punched fibers may be a mixture of polyacrylonitrile pre-oxidized fibers and viscose-based pre-oxidized fibers, and the mixing ratio (mass ratio) of the polyacrylonitrile pre-oxidized fibers and the viscose-based pre-oxidized fibers may be 1 to 99: 1 or 1: 1-99, in the technical scheme of the invention, the proportion is 1-10: 1, in particular 3 to 8:1, the technical objects of the present invention are more easily achieved, such as 3: 1. 4:1 or 8: 1.

the carbonization and activation processing technology adopts a synchronous carbonization and activation process, the prepared preoxidized fiber felt (namely the carbon fiber felt) is fed into a hearth of an activation furnace at room temperature, then nitrogen is introduced into the hearth, carbonization and temperature rise are carried out at different temperature rise rates, water vapor is introduced after a certain temperature is reached, constant-temperature activation is carried out for a certain time after a preset temperature is reached, finally the carbon fiber felt is cooled to a certain temperature under the protection of the nitrogen, and then the carbon fiber felt is naturally cooled to the room temperature, so that the activation and carbonization treatment of the carbon fiber felt are completed.

In some embodiments of the invention, the needling is performed in a direction perpendicular to the lamination plane (i.e., in the Z-axis direction).

In certain embodiments of the invention, the needling density is from 10 to 50 needles/cm²。

In some embodiments of the invention, the carbonization treatment comprises heating to 1000-1500 ℃ and introducing steam to carbonize the carbon fiber felt.

In an embodiment of the present invention, the carbonization is performed in a nitrogen atmosphere.

In certain embodiments of the invention, carbonization is increased to 1000-1500 ℃ at a temperature increase rate of 5-15 ℃/min.

In some embodiments of the invention, steam is introduced after the temperature is raised to the carbonization temperature of 1000-1500 ℃, and the introduction rate of the steam is 3-15 g/min.

In certain embodiments of the invention, the carbonization time is 20 to 50 min.

In certain embodiments of the invention, cooling to 150-; then naturally cooling to room temperature.

The nitrogen is high-purity nitrogen, the purity of the nitrogen is more than 99.99999%, and the introduction pressure is not lower than 0.2 MPa.

The preparation method can control the surface aperture of the prepared activated carbon fiber felt to be within the range of not more than 0.7nm, or not more than 0.65nm, or not more than 0.6nm, or 0.6-0.7 nm.

The activation carbonization can be realized by a carbonization activation heating device, the device comprises a heat-preservation hearth, a heater and a temperature control device, high-purity nitrogen is introduced into the whole heat-preservation hearth through a flow inlet, and the gas flow is controlled by a flow controller; meanwhile, activating steam is introduced through a flow inlet, and the flow rate of the activating steam is controlled by a flow controller. Therefore, the process for preparing the activated carbon fiber felt of the invention based on the device is particularly easy to realize the process. For example, the carbonization activation heating apparatus may be an apparatus as shown in fig. 2.

Therefore, in the production method of the present invention, the carbonization-activation treatment is based on the above-described carbonization-activation heating apparatus, which includes: sending the prepared pre-oxidized fiber felt (namely the carbon fiber felt) into a heat preservation hearth 1 at room temperature, then introducing nitrogen into the hearth through a flow inlet 4, controlling the introduction pressure of the nitrogen to be not lower than 0.2MPa through a flow controller 5, controlling a heater 2 to heat to 1000-plus-one temperature at the heating rate of 5-15 ℃/min through a temperature control device 3, then introducing activating water vapor through a flow inlet 6, controlling the flow of the water vapor to be 3-15g/min through a flow controller 7, carbonizing for 20-50min at the temperature of 1000-plus-one temperature 1500 ℃, and then continuously cooling to 150-plus-one temperature of 200 ℃ in a nitrogen atmosphere; and then naturally cooling to room temperature to complete the activation and carbonization treatment of the carbon fiber felt.

In a third aspect of the invention, the invention provides the use of the activated carbon fiber mat in the field of hydrogen energy storage and/or adsorption.

The surface aperture of the activated carbon fiber felt is not higher than 0.7nm, or not higher than 0.65nm, or not higher than 0.6nm, or 0.6-0.7nm, and the hydrogen absorption rate is within the range of 2.5%.

The activated carbon fiber felt has the characteristic of controllable surface pore structure, has the surface pore diameter of not more than 0.7nm, or not more than 0.65nm, or not more than 0.6nm, or 0.6-0.7nm, has higher adsorption activity, can be particularly used for hydrogen absorption and storage, and has the advantages of economy, high hydrogen storage capacity, quick desorption, long cycle service life, easy realization of large-scale production and the like.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a schematic diagram of the felt structure of the activated carbon fiber felt of the present invention; wherein 1, 2 and 3 are respectively of a net tire structure, and 4 is of a needle-punched fiber; the felt body of the activated carbon fiber felt is obtained by laminating different net tires 1, 2 and 3 and then performing needling treatment with different densities in the Z-axis direction by using needling fibers 4.

FIG. 2 is a schematic diagram of a carbonization activation heating device of an activated carbon fiber felt, which comprises a heat preservation hearth 1, a heater 2 and a temperature control device 3, wherein high-purity nitrogen is introduced into the whole heat preservation hearth 1 through a flow inlet 4, and the nitrogen flow is controlled by a flow controller 5; meanwhile, the activating steam is introduced through a flow inlet 6, and the flow of the steam is controlled by a flow controller 7.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The reagents or starting materials used in the present invention can be purchased from conventional sources, and unless otherwise specified, the reagents or starting materials used in the present invention can be used in a conventional manner in the art or in accordance with the product specifications. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred embodiments and materials described herein are intended to be exemplary only.

The following embodiments can be implemented based on the apparatus shown in fig. 2 or based on other apparatuses having a holding furnace, a heater, a temperature control device, and a flow control device.