JPS6037048B2 - Activated carbon manufacturing method - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for producing micropore powdered activated carbon made from grains such as old rice, which is currently a problem in excess.
In particular, the present invention relates to a method for producing activated carbon in which the activation process is performed in two stages.

Generally, methods for producing powdered activated carbon include a steam activation method, a zinc chloride activation method, etc., which mainly use sawdust, charcoal, etc. as raw materials.

The steam activation method uses sawdust carbonized at 400 to 500 qo or charcoal crushed to 8 to 30 mesh and 700 to 90 qo
This is a method of activating by adding water vapor at 0qo, and the zinc chloride activation method involves drying sawdust, etc., and then ripening it in a mixed solution of subsalt chloride and hydrochloric acid.
This is a method of grilling cod at 00oo. Powdered activated carbon manufactured by these general manufacturing methods belongs to the so-called macropore type with large adsorption pores, and is suitable for use in liquid phase adsorption that performs decolorization and adsorption reactions in the liquid phase. It is not suitable as activated carbon for adsorption of impure bacteria generated in soil for agricultural and horticultural purposes.

That is, since vapor phase adsorption is used to adsorb evaporated fuel, micropore activated carbon with small adsorption pores is required, and a method for producing such micropore activated carbon is desired. The present inventor has devised the present invention in view of the above-mentioned problems, and the purpose thereof is to provide a method for producing activated carbon suitable for vapor phase adsorption such as adsorption of evaporated fuel. In order to achieve the object, the present invention involves adding at least one of sodium silicate or camphor algae to grains such as rice, carbonizing it under predetermined conditions, and then adding steam to this carbonized product. It is characterized in that it is further activated by adding carbon dioxide gas.

The manufacturing method using old brown rice as the raw material will be explained below.

The old brown rice used as a raw material is usually oval granules with a major axis of 7 to 8 sides, and the main components are carbohydrates, oils and lipids, etc.
Contains sugar, amino acids, etc. and approximately 15% water.

The above old brown rice is dried to reduce the water content to 1/3 or less of the above amount, and then crushed and sized to make the carbonization process easier.
．． Shape into neck grains with 2 to 0.7 ribs. Next, sodium silicate or cinnamon earth is added to the obtained jaw granules, and the mixture is put into a rotary kiln and carbonized at a temperature of 300 to 35,020 ℃ to remove oil lipids, sugars, and amino acids in the raw materials.

The carbonization step follows the carbonization step, and since the conditions in the carbonization step determine the structure of the adsorption pores, it is the most important step in the activated carbon production process.

That is, in order to obtain micropore activated carbon suitable for gas phase adsorption, carbonization conditions such as temperature must be appropriately controlled, and the amount of volatile components remaining in the carbide must be appropriate. When there are many volatile substances in the carbide, the activation time is shortened due to a synergistic exothermic phenomenon during activation heating, and the adsorption structure that develops during activation becomes micropores. Therefore, in the carbonization step of the present invention, the temperature is kept below 500 oo, the residence time in the furnace is set to 60 to 90 minutes, and calcium chloride is added to effect slow carbonization. The volatile content of the carbide thus obtained was approximately 15%, and the fixed carbon content was approximately 62%.
Compared to conventional charcoal made from sawdust carbide or miscellaneous wood, which has a volatile content of about 30% and a fixed carbon content of about 60%, the volatile content has been reduced to about half. Next, the carbide obtained by the carbonization step is activated by an activation step.

In this embodiment, the activation process is divided into one stage, an activation zone and an etching zone. That is, the first half of the rotary kiln is used as an activation zone where steam is added instantaneously, and the second half is used as an etching zone where carbon dioxide gas is supplied to assist the activation reaction.

Table 1 shows the experimental results of the effects on the adsorption performance of activated carbon obtained by varying the activation time, temperature, amount of water vapor added, etc. Table 1 Activation conditions for producing powdered activated carbon using rice as raw material As is clear from Table 1, the activation time is 90 to 180
It is preferable that the heating temperature is 1000 to 1 minute.
The optimal temperature is 100°C, and adsorption performance decreases when the temperature exceeds 11,500°C, and the amount of water vapor added is also 1.5°C. It can be seen that M sound or higher is preferable.

The activated carbon obtained by the above-described process has micropores for adsorption and is highly durable in adsorption.

The adsorption capacity will be explained below in comparison with conventional sawdust or activated carbon made from charcoal, with reference to Table 2 and the attached drawings. Table 2 compares the caramel decolorization rate and methylene flu dye adsorption rate of activated carbon according to the method of the present invention and activated carbon according to the conventional method.

Table 2 Liquid phase adsorption ratio of activated carbon by type The caramel decolorization test uses caramel liquid specified in JIS standards, and the decolorization rate is measured using a photometer after adsorption reaction is performed on various activated carbons for 3 minutes. The adsorption test for methylene flue was carried out by measuring the adsorption amount of various activated carbons using chemical balance.

As is clear from the values in the table, the activated carbon produced by the method of the present invention has a low degree of adsorption of caramel dyes adsorbed by the macropore activated carbon, and a high degree of adsorption of basic dyes such as methylene blue, which is adsorbed by the micropore activated carbon. It can be seen that the pores are structured into micropores.

The figure is a graph comparing adsorption persistence, in which various activated carbons were added to a 2% aqueous solution of methylene flue, and the adsorption properties were measured every unit time using a photometer.

This graph shows that the activated carbon produced by the method of the present invention has excellent adsorption durability. As described above, according to the present invention, after carbonizing grains such as old brown rice with sodium silicate or cinnamon to remove oil lipids, sugars, and amino acids,
Slow calcination carbonization under appropriate conditions yields microporous carbide, which is then activated in a two-step activation process in which water vapor is added to this at a predetermined temperature and carbon dioxide gas is further added. It is possible to obtain activated carbon that can be used effectively and help conserve resources, has micropores suitable for gas phase adsorption, and has long-lasting adsorption performance.

[Brief explanation of the drawing]

The drawing is a graph comparing the adsorption sustainability of activated carbon according to the method of the present invention and activated carbon according to the conventional method.

Claims (1)

[Claims] 1. A step of adding at least one of sodium silicate or diatomaceous earth to grains and carbonizing the grains, carbonizing the dry-flowed grains, and adding steam to the carbonized product. A method for producing activated carbon, which comprises a two-step activation process consisting of a process of adding carbon dioxide gas. 2. The method for producing activated carbon according to claim 1, wherein the grain is rice grain. 3. The method for producing activated carbon according to claim 1 or 2, wherein the grains are dried, crushed and sized. 4. The method for producing activated carbon according to any one of claims 1 to 3, wherein the carbonization step is performed by adding calcium chloride. 5. The method for producing activated carbon according to any one of claims 1 to 4, wherein the temperature of the carbonization step is 500° C. or less, and the time of the carbonization step is 60 minutes to 90 minutes. . 6. The method according to any one of claims 1 to 5, characterized in that the temperature of the activation step is in the range of 1000° C. to 1100° C., and the time of the activation step is 90 minutes to 180 minutes. Method for producing activated carbon.