JPH0543346A - Production of active carbon structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for activating block-type activated carbon quickly and uniformly without causing cracking, which is a problem during activation. [Structure] In a method for producing an activated carbon structure by carbonizing and activating a polymer having a high residual carbon ratio, when activating, a substance to be activated is wrapped with a layered material containing carbon as a main component to activate. Is a method for manufacturing an activated carbon structure.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an activated carbon structure. More specifically, the present invention relates to a method for producing an activated carbon structure with less warpage and cracking.

[0002]

2. Description of the Related Art Activated carbon is widely used for applications such as wastewater treatment and deodorization treatment. More recently, they have begun to be used as electrodes of electric double layer capacitors. The activated carbon used for this purpose satisfies the requirements for improved performance of capacitors, especially high performance and low internal resistance.
It is required to have high density, block shape, and good impregnation property with an electrolytic solution.

Generally, as a method for producing activated carbon, raw materials such as coal or coconut shells are crushed into granules or powder, and if necessary, further granulated into pellets and then carbonized. , The method of activation is adopted. With such a powder, a product of stable quality can be obtained by a method of activating the raw material while rotating it with a rotary kiln. However, the block-like activated carbon cannot be manufactured by such a method.

[0004]

[Problems to be Solved by the Invention] The present applicant has previously proposed a method for producing an activated carbon structure by using a phenol resin foam as a raw material and carbonizing and activating it. In the case of such a structure, unlike the activation of powder (1)
There are problems that activation becomes uneven depending on the site of the structure, (2) warpage and cracking are likely to occur, and (3) activation speed is slow. As a method for improving the point (3), it is conceivable to increase the activation temperature or increase the water vapor concentration, but these methods lead to cracking or warpage of the activated material.

The present inventors have arrived at the present invention as a result of extensive studies to find a method for activating block-like activated carbon rapidly and uniformly without cracking, which is a problem during activation.

[0006]

Means for Solving the Problems That is, the present invention is a method for producing an activated carbon structure by carbonizing and activating a polymer having a high residual carbon ratio. The method for producing an activated carbon structure is characterized in that the activated carbon structure is encased in a layered product and activated.

The present invention will be described in more detail. The polymer having a high residual carbon ratio in the present invention is, for example, a phenol resin, a furan resin, a polyvinyl chloride resin, etc. When treated at a high temperature of 500 ° C. or higher in an inert atmosphere, the ratio of carbon residue remains as the original weight. It refers to a polymer that is 20% or more of the coalescence. In the present invention, a phenol resin is preferable among them, and a resol type phenol resin can be particularly preferably used. As a resin composition using such a resol-type phenol resin, for example, a method of mixing the resol-type phenol resin with an evaporative foaming agent, a curing agent, followed by foaming and curing, or a resol-type phenol resin And a liquid and / or powdery material having a low residual carbon rate and mixed and cured.

In the present invention, the resin composition is carbonized and activated to produce an activated carbon structure. At this time, the material to be activated is wrapped with a layered material containing carbon as a main component for activation.

Carbonization is carried out in an inert atmosphere. The non-oxidizing atmosphere means, for example, Ar gas, He gas, N2 gas, halogen gas, ammonia gas, CO gas, hydrogen gas, a mixed gas thereof, a water gas or the like. The temperature for carbonization is preferably in the range of 500 ° C to 1200 ° C, particularly 600 to 900 ° C.

The carbon porous body obtained as described above is
Further, activation treatment is applied to activate. The activation step may be continuous with the carbonization step or may be a step separate from the carbonization step. Activation of the carbon porous body is performed by heating the carbon porous body in an atmosphere of an oxidizing gas or a mixed gas of an oxidizing gas and an inert gas.

As the oxidizing gas for activating the polymer, known oxidizing gases such as air, water vapor, carbon dioxide gas, water gas and the like can be adopted. The temperature at which activated carbon is produced by carbonizing and activating the polymer is usually 600 to 1 although it depends on the type and concentration of the activating gas.
A range of 200 ° C., preferably 750 to 1000 ° C. is adopted.

The layered product containing carbon as a main component in the present invention is, for example, a graphite plate, a woven or non-woven fabric of carbon fibers, or so-called C /, which is produced by impregnating them with a resin and then carbonizing them again. C composite, or a carbon fiber made into a paper shape to have a thickness by a method such as forming a honeycomb, or a polymer foam having a high residual carbon ratio as described above is carbonized. The obtained carbon porous material or the like can be used. Among these, carbon fiber non-woven fabric and C / C composite having gas permeability and large surface area are preferable.

The required thickness of the layered material depends on the concentration of the activating gas and the wind speed, but is preferably 1 to 50 mm.
Is in the range. For the purpose of preventing warpage, the carbon layered material is more preferably used together with a rigid ceramic foam.

As a method for wrapping the activator, a box-shaped product made of a carbon layered product is prepared, the activator is placed therein, a frame-shaped product is prepared, and the activator is sandwiched between them. Can be adopted. The role of the layered material serves to allow the oxidizing gas to permeate at a limited rate. Further, although not clear, the carbon layered material reacts with the oxidizing gas to form carbon dioxide gas in the system in view of the effect that the number of cracks at the end of the present invention is small and the activation rate of the whole is improved. It is presumed that it acts to soften the local runaway reaction between the carbon dioxide gas and the polymer plate-like material and to promote the activation reaction as a whole.

[0015]

【Example】

Example 1 100 parts by weight of a resol type phenol resin, 10 parts by weight of paratoluene sulfonic acid as a curing agent, and 1.5 parts by weight of Freon 123b as a foaming agent were sufficiently stirred and mixed with a high speed mixer. Pour the resulting mixture into a wooden mold,
After covering with a lid, the product was placed in an air oven at 80 ° C. and heated for 30 minutes for foaming to obtain a foam cured product block. From this block, a plate having an outer diameter of 10 cm in length, 10 cm in width, and 3 mm in thickness was cut.

Each of the eight plates has an inner diameter of 10.5c in the vertical direction.
m, width 10.5 cm, width 4 mm, thickness 5 mm, put in a frame box made of carbon fiber non-woven fabric (porosity 70%), and then put 8 of these boxes in the center of the muffle furnace, and under nitrogen atmosphere. After raising the temperature to 900 ° C. at a temperature rising rate of 60 ° C./hour, a mixed gas having a mixed molar ratio of N 2 gas / steam of 0.8 / 0.2 was flowed while maintaining the temperature for 3 hours. ..

An activated carbon porous material was obtained by the above method. The warp of this plate, the presence or absence of cracks, and the benzene adsorption degree at the central portion and the end portion were measured. The benzene adsorption degree was determined by using a thermobalance as a value (%) obtained by dividing the weight increase due to adsorption under a saturated vapor of 25 ° C. at about 100 mg of the sample by the weight of the sample. The results are shown in the table. Shown in 1.

Example 2 In Example 1, the activation temperature and activation time were 850 and 850, respectively.
The same procedure as in Example 1 was repeated except that the temperature was changed to 5 ° C. and the time was changed to 5 hours. The results are shown in the table. Shown in 1.

Example 3 Instead of the carbon fiber nonwoven fabric used in Example 2, C /
Example 2 was performed in the same manner as in Example 2 except that a C composite board box (porosity 75%) was used. The results are shown in the table. Shown in 1.

Comparative Example 1 The procedure of Example 1 was repeated, except that the carbon fiber nonwoven fabric box used in Example 1 was not used and the plate of the foamed cured product was placed in a muffle furnace for activation. The results are shown in the table. Shown in 1.

COMPARATIVE EXAMPLE 2 In Comparative Example 1, the activation temperature and activation time were 850 and 850, respectively.
The same procedure as in Comparative Example 1 was repeated except that the temperature was changed to 5 ° C. and the time was changed to 5 hours. The results are shown in the table. Shown in 1.

Comparative Example 3 The procedure of Example 1 was repeated except that a ceramic fiber board box was used instead of the carbon fiber nonwoven fabric in Example 1. The results are shown in the table. Shown in 1.

Comparative Example 4 The procedure of Example 1 was repeated, except that a heat-resistant brick box was used instead of the carbon fiber nonwoven fabric. The results are shown in the table. Shown in 1.

[0024]

[Table 1]

[0025]

EFFECTS OF THE INVENTION According to the method for producing an activated carbon structure using the layered product containing carbon as a main component of the present invention, cracking during activation is less than that in the conventional method not using the layered product, and the yield is higher. Is improved. In addition, the activation speed is improved. Furthermore, the activation rate of the entire structure becomes more uniform, and the adsorption performance of the entire structure improves. As a result, high density, high adsorption performance, especially useful as electrodes for electric double layer capacitors and deodorizing filters,
In addition, it is possible to efficiently manufacture an activated carbon structure having an excellent liquid impregnation property.

Claims (2)

[Claims] 1. A method for producing an activated carbon structure by carbonizing and activating a polymer having a high residual carbon rate, in which activation is performed by encapsulating a substance to be activated with a layered material containing carbon as a main component. A method for producing an activated carbon structure, comprising: 2. The production method according to claim 1, wherein the layered product containing carbon as a main component is a woven or non-woven fabric of carbon fibers.