JPH08169706A - Activated carbon and its production - Google Patents

Abstract

PURPOSE: To produce an activated carbon with the adsorptivity per volume and hardness improved. CONSTITUTION: This activated carbon consists of a base carbon formed with a porous activated carbon and the additional activated carbon component introduced and held in the pore of the base carbon. The activated carbon is produced as follows. Namely, the pore of the base carbon is impregnated with a liq. contg. the carbon component to form an impregnated base carbon in the impregnation stage 2. The impregnated base carbon is heated to carbonize the carbon component in the carbonization stage 3. The carbonization stage consists of a dry distillation stage 31 and an activation stage 32. An activated carbon having higher adsorptivity and hardness is obtained by this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to activated carbon having a high density, a high adsorption capacity per volume, and a reduced hardness, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a conventional method for producing activated carbon, as shown in FIG. 3, a carbon-containing substance typified by a coal raw material is finely pulverized, and a binder is mixed in the finely pulverized substance to carry out kneading and molding. After that, it is a method of activating the base carbon obtained by sieving the material which has been heated and carbonized and dried to produce porous activated carbon.

Such a manufacturing method or a manufacturing method similar to this is disclosed in JP-A-4-21511 and JP-A6-1.
For example, the characteristics of the activated carbon manufactured by such a manufacturing method are disclosed.

[0004]

However, in the activated carbon produced by the conventional production method, when activated, wide pores are formed from the micropores to the macropores (average diameter of 0.1 to 50 μm), and the strength is lowered. In addition, the increase in macropores that do not participate in adsorption reduces the adsorption performance per volume. That is, the activated carbon produced by the conventional production method has a problem in that the adsorption performance per volume is limited and the hardness is reduced to some extent.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an activated carbon which has improved adsorption performance per unit volume of activated carbon, and further has a reduced hardness decrease, and a method for producing the activated carbon. .

[0006]

According to the present invention, when a porous base material carbon is impregnated with a liquid containing a carbon component to be carbonized, an additional activated carbon component is present in the pores (in the macropores) existing in the base carbon. It was made based on the discovery that it can form. That is, the activated carbon of the present invention is
It is characterized in that it is composed of a base carbon formed of porous activated carbon and an additional activated carbon component introduced and retained in the pores of the base carbon.

The method for producing activated carbon according to the present invention comprises: an impregnation step of impregnating a liquid containing a carbon component into pores of a porous base carbon to obtain an impregnated base carbon; and heating the impregnated base carbon.
A carbonization step of carbonizing the carbon component to obtain an added activated carbon component. Here, the base carbon may be produced by pulverizing a carbon-containing substance into fine powder, kneading and molding the fine powder with a binder, heating the molded product, and carbonizing and carbonizing. it can. In addition, the carbon-containing substance may be any one of coal, coconut shell, wood and formed coal. Further, the liquid containing the carbon component in the impregnation step is preferably a coal-based binder. The ratio of impregnating the liquid containing the carbon component is appropriately in the range of 3 to 50 parts by weight with respect to 100 parts by weight of the base carbon.

In the method for producing activated carbon, it is desirable that the carbonization step comprises a carbonization step and an activation step. The former dry distillation step is a step of elevating the temperature from room temperature to 400 ° C. or higher in a nitrogen atmosphere, and the latter activation step is a step of heating in a steam atmosphere. Activated carbon can be produced.

According to such a method for producing activated carbon of the present invention, the above-mentioned activated carbon of the present invention can be produced.

[0010]

In the method for producing activated carbon according to the present invention, the liquid containing the carbon component is impregnated into the pores of the porous base carbon (particularly in the macropores), and the liquid containing the carbon component is carbonized to obtain the additional activated carbon. As an ingredient. As a result, an activated carbon is produced which is composed of a base carbon formed of porous activated carbon and an additional activated carbon component introduced and retained in the pores of the base carbon. In the activated carbon of the present invention produced in this manner, the added activated carbon component is retained in the macropores to reduce the diameter of the pores thereof, thereby forming a micropore having an adsorptive property to realize a high strength structure.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (Example) The flow of the method for producing activated carbon as an example of the present invention is shown in FIG. The present manufacturing method includes an impregnating step 2 in which the pores of the porous carbon substrate manufactured in the carbon substrate manufacturing step 1 are impregnated with a liquid containing a carbon component to obtain carbon impregnated carbon material, and the impregnated carbon substrate material. Carbonization step 3 in which carbon is heated to carbonize the carbon component to give an additional activated carbon component.

The above-mentioned base carbon production step 1 is composed of a fine pulverization step 11, a kneading step 13, a forming step 14, and a carbonization step 1 in this order.
5 and a sieving step 15, which is a step of producing a porous base carbon material. First, in the fine pulverization step 11, the coal material 10 as the carbon-containing substance substance was pulverized with a known fine pulverizer such as a bantam mill to obtain fine powder. Next, in the kneading step 13, 100 parts by weight of this fine powder is blended with a pitch-based binder in a ratio of 30 parts by weight and kneaded.
A kneaded product was produced. Then, the kneaded material formed in the forming step 14 was carbonized and dry-distilled at a rate of 2.5 ° C./min from room temperature to 700 ° C. in a nitrogen atmosphere in the next carbonization step 15. The dry carbon thus obtained was sieved in a sieving step 16 to obtain a carbon base material.

In this way, the base material carbon in which the pores are formed in a wide range from the micropores to the macropores is manufactured by the base material carbon manufacturing step 1, which is the core of the present invention, and the impregnating step 2 and the subsequent carbonization. It was supplied to Step 3 as a raw material. In the impregnation step 2, 20 parts by weight of coal tar as a liquid containing a carbon component was impregnated into the above base carbon at room temperature. Then, the coal tar soaked into the macropores in the carbon base material, and the impregnated carbon base material holding the coal tar containing carbon in the macropores was generated.

The carbonization step 3 includes a carbonization step 31 and an activation fixing 3
Consists of two. In the carbonization step 31, the impregnated base carbon is
Similar to the carbonization step 15 in the base carbon manufacturing step 1, the coal impregnated into the base carbon was heated from room temperature to 700 ° C at a rate of 2.5 ° C / min in a nitrogen atmosphere. The tar was subjected to carbonization distillation. Then, in the activation step 31, the product of the dry distillation step 31 in which the carbon content of the carbonized coal tar was held in the macropores in the base carbon was activated in a steam atmosphere at 950 ° C. for 6 hours.

The activated carbon production method of the present invention is different from the conventional production method in that the impregnation step 2 and the dry distillation step 31 are newly added. Thus, as an example of the present invention, it is characterized by comprising a base material carbon formed of porous activated carbon and an additional active carbon component introduced and retained in the pores (inside the macropores) of the base material carbon. Activated carbon was produced.

(Comparative Example) In order to make a comparative study with the activated carbon produced by the production method of the present invention, activated carbon was produced by the production method of the prior art in which the impregnation step 2 and the carbonization step 31 which are the features of the present invention are omitted. . That is, the same carbon raw material as in the above-described example was treated in the same base carbon production step to carbonize and dry carbonize the base carbon, and without impregnating dry distillation, the same activation step was applied to produce activated carbon as a comparative example. did.

(Comparative Evaluation) Table 1 shows activated carbon as an example of the present invention produced by subjecting the base carbon to the impregnation step 2 and the carbonization step 3 which are the characteristics of the present invention as described above. The physical property values of activated carbon as a comparative example manufactured by a conventional manufacturing method in which only the previous activation step (the degree of activation is the same as in the example) were performed according to the base carbon are shown in comparison. From this table,
It is clear that the activated carbon of this example is superior to that of the comparative example in any of the benzene adsorption amount, hardness, specific surface area, and pore distribution.

[0018]

[Table 1] By the way, as shown in FIG. 2, there was a difference in pore diameter distribution between the activated carbon of the example and that of the comparative example. That is,
In the range in which the pore diameter is not so effective for adsorption of about 1 to 10 μm, the Example clearly has a smaller pore volume than the Comparative Example, and conversely, the micropores having the pore diameter of 0.1 μm or less and having an effective adsorption effect are obtained. There was a tendency for a large number. Therefore, in this example, the amount of macropores not involved in adsorption was decreased, and the ratio of micropores effectively involved in adsorption was slightly increased. Therefore, it is considered that the activated carbon of the present invention had an improved adsorption capacity per volume.

Incidentally, the vertical axis of the graph of FIG. 2 is the differential value of the pore (micropore) volume in the minimum section, which represents the pore distribution of the intermediate product, and its unit is [cc / g]. As described above in detail, according to the activated carbon of the present invention and the method for producing the same, since the activated carbon having the added activated carbon component retained in the pores is provided, the adsorption performance per volume of the activated carbon is improved, and the hardness thereof is further improved. It can be seen that the decrease could be suppressed to a low level.

(Comparison of Base Material Carbon as Intermediate Product) For reference, the base material carbon as the intermediate product 1 which has undergone the base material carbon production step 1 in the above-mentioned examples and the above-mentioned similar Table 2 shows the physical property values of the base carbon as the intermediate product 2 that has undergone the base carbon manufacturing process in the comparative example. Here, the base carbon as the intermediate product 1 was to be processed into activated carbon as an example of the present invention through the impregnation step 2, the carbonization step 31, and the activation step 32. On the other hand, the base carbon as the intermediate product 2 is
Only the conventional activation process should be performed and it should be processed into the conventional activated carbon as a comparative example.

In Table 2, the reason why the physical properties are different is that the carbon-containing component is formed in the macropores inside the intermediate product to reduce the cavities and increase the density per volume. Here, the intermediate product 1 is a tar-impregnated product, and the intermediate product 2 is a non-impregnated product. The reason why the packing densities are different is that the cavities inside the intermediate product are reduced by the carbon-containing component and the density per volume is increased. The intention is to improve the adsorption performance and hardness per volume by using high-density dry-distilled carbon in the subsequent activation step.

The intermediate product 1 after impregnation with the binder
Has different physical properties from the intermediate product 2 of the comparative example (general product), but this is the difference caused by the impregnation, and the dry-distilled charcoal before impregnation was completely the same. Therefore, the impregnation effect can be confirmed.

[0023]

[Table 2]

[0024]

EFFECTS OF THE INVENTION According to the activated carbon of the present invention and the method for producing the same, activated carbon having an added activated carbon component retained in its pores is provided, so that the adsorption performance per volume of activated carbon is improved,
Furthermore, the decrease in hardness can be suppressed to a small level.

[Brief description of drawings]

FIG. 1 is a block diagram showing a method for producing activated carbon according to the present invention.

FIG. 2 is a graph showing the distribution of pores in the activated carbon of the present invention.

FIG. 3 is a block diagram showing a conventional method for producing activated carbon.

[Explanation of symbols]

1: Base carbon production process 2: Impregnation process 3: Carbonization process 31: Carbonization process 32: Activation process

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[Procedure amendment]

[Submission date] January 23, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The carbonization step 3 includes a carbonization step 31 and an activation step 3.
Consists of two. In the carbonization step 31, the impregnated base carbon is
Similar to the carbonization step 15 in the base carbon manufacturing step 1, the coal impregnated into the base carbon was heated from room temperature to 700 ° C at a rate of 2.5 ° C / min in a nitrogen atmosphere. The tar was subjected to carbonization distillation. Then, in the activation step 31, the product of the dry distillation step 31 in which the carbon content of the carbonized carbonized coal tar was held in the macropores in the base carbon was activated in a steam atmosphere at 950 ° C. for 6 hours.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018]

[Table 1] By the way, as shown in FIG. 2, there was a difference in the distribution of the pore diameter between the intermediate product of the example and that of the comparative example. That is, in the range where the pore diameter is not so effective for adsorption of about 1 to 10 μm, the Example obviously has a smaller pore volume than the comparative example, and conversely has an effective adsorption effect of the pore diameter of 0.1 μm or less. Micropores tended to be slightly more numerous. Therefore, in this example, the amount of macropores not involved in adsorption was decreased, and the ratio of micropores effectively involved in adsorption was slightly increased. Therefore, it is considered that the activated carbon of the present invention had an improved adsorption capacity per volume.

Claims (8)

[Claims] 1. An activated carbon comprising a carbon base material formed of porous activated carbon and an additional activated carbon component introduced and retained in the pores of the carbon base material. 2. An impregnation step of impregnating a liquid containing a carbon component into pores of a porous base carbon to obtain an impregnated base carbon, and heating the impregnated base carbon to carbonize the carbon component. A method for producing activated carbon, comprising a carbonization step of using an additional activated carbon component. 3. The base carbon is produced by finely pulverizing a carbon-containing substance into fine powder, kneading the fine powder with a binder, heating the molded product, and carbonizing it. The method for producing activated carbon according to claim 2. 4. The method for producing activated carbon according to claim 2, wherein the carbon-containing substance is any one of coal, coconut shell, wood and formed coal. 5. The method for producing activated carbon according to claim 2, wherein the liquid containing the carbon component is a coal-based binder. 6. The method for producing activated carbon according to claim 2, wherein the carbonization step includes a carbonization step and an activation step. 7. The method for producing activated carbon according to claim 6, wherein the carbonization step is a step of raising the temperature from room temperature to 400 ° C. or higher. 8. The method for producing activated carbon according to claim 6, wherein the activation step is a step of heating in a steam atmosphere.