JPH02307818A - Production of activated carbon - Google Patents

Abstract

PURPOSE:To easily obtain good-quality activated carbon having a large specific surface area from caking coal with high activation yield by adding the specified amount of pulverized vegetable to pulverized coal and thereafter pressurizing and molding the mixture to produce granulated coal, carbonizing, grading and activating this granulated coal. CONSTITUTION:Only the slightly-caking coal and caking coal or coal blended with both non-caking coal and caking coal are preferably pulverized smaller than 74mum. Vegetable which has mean particle diameter smaller than 100mum and has been dried and pulverized is added at 11wt.% or more and less than 50wt.% to this coal and mixed therewith. This mixture ie pressurized and molded to produce granulated coal. This granulated coal is carbonized in a carbonizing furnace and graded and thereafter activated. Further the granulated coal is intactly granulated, carbonized and thereafter activated. Acidic gas and liquid substance are generated from the above-mentioned vegetable in the heating stage. This vegetable is not softened and melted and therefore coal particles are prevented from being tightly welded with each other. Macro holes are formed so that activating gas is easily diffused into the inside of carbide at the time of activation. When the loadings of vegetable are less than 11wt.%, the macro holes are not sufficiently formed. Further when the loadings thereof are 50wt.% or more, the mechanical strength of granulated coal is deteriorated and powdered and the yiold of activated carbon is deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing activated carbon. Activated carbon produced by this method can be used to remove harmful substances in water and wastewater, absorb volatile organic substances such as gasoline, or odors.

BACKGROUND OF THE INVENTION Activated carbon using coal as a raw material is produced by producing a carbide and activating this carbide using various methods.

In this case, in order to produce high-quality activated carbon, it is important to select raw material coal and process it in the process of producing carbide so that the coal does not soften and melt, forming carbides with thick pore walls and a small specific surface area. .

For this reason, various methods have been proposed in the past. That is, in Japanese Patent Application Laid-Open No. 50-5199Ei, activated carbon is produced by selecting coal that has weak or no caking properties, such as low-coalization coal such as brown coal that does not soften or melt even when heated.

However, when these brown coals are used as raw materials, a binder is required. Furthermore, JP-A-50-125989 shows an example in which Black Creek coal from Alabama, USA is used, but in this case, a naphthalene sulfonated foryaline condensate or its salt is added in the presence of water. It is used as a binding agent. As described above, some kind of binder is used in these methods of producing activated carbon.

The use of these binders complicates the activated carbon manufacturing process and increases cost.

On the other hand, JP-A-50-152993 proposes a method in which agglomerated granulated coal is treated with an oxygen-containing gas without using a binder.

In this way, currently known methods for producing activated carbon include using coal that does not melt even when carbonized, or when using coking coal, it is made infusible with an oxygen-containing gas and then carbonized and activated to produce activated carbon. It's a method.

Furthermore, US Pat. No. 3,483,134 also discloses a method of adding 1 to 10% grain to pulverized coal.

Problems to be Solved by the Invention However, in these known activated carbon production methods, the selection range of activated carbon raw material coal is narrowed. In addition, when coking coal is used, it becomes infusible due to oxygen-containing gas, so
After agglomeration, the progress of oxidation is different between the surface and the inside, making it difficult to produce homogeneous unmelted lump charcoal.If homogeneous infusible lump charcoal is to be produced, it is necessary to lengthen the oxidation treatment time. However, in order to obtain activated carbon with a higher specific surface area, it is necessary to increase the activation time and reduce the activation yield.

From the above points, it is important and strongly desired to establish a method for producing high-quality activated carbon with a high specific surface area from coking coal simply, inexpensively, and with a high activation yield.

Means for Solving the Problems The present invention achieves its objects by: (1) adding 11% by weight or more and less than 1-50% by weight of pulverized plants to pulverized coal, followed by pressure molding and granulation; After turning into charcoal, carbonizing it in a carbonization furnace and sizing it, it is activated.

(2) Add 11 liters of dried and pulverized plants to pulverized coal.
After adding % by weight or more and less than 50% by weight, it is press-molded and made into a charcoal as it is, or after being sized, carbonized in a carbonization furnace, and then activated.

(3) After adding 11% or more and less than 50% by weight of crushed plants to crushed coal, the mixture is pressure-molded to form granulated coal, either as is or after granulation, and the granulated coal is oxidized with oxygen. The method is characterized in that carbonization is activated after oxidation treatment at 100° C. or higher and lower than 350° C. using a reactive gas.

The present invention will be explained in detail below.

A wide range of coals, from lignite to anthracite, are used as raw materials for coal-based activated carbon. However, in the production of high-grade activated carbon, granulated coal is used, which is made by finely pulverizing coking coal and granulating it.

Therefore, in order to prevent the softening and melting phenomenon of granulated coal during the carbonization process, the granulated coal is infusible using an oxygen-containing gas. This increases the processing time and makes it difficult to achieve homogeneous infusibility. Also, specific surface M 1400m'/
If you want to produce g of activated carbon, the activation yield is 20%.
It becomes below.

Therefore, the present invention pulverizes the coking coal to increase the specific surface area of the coking coal, and at the same time performs infusible treatment from the inside of the granulated coal or from the inside and outside simultaneously. As a result of various research, we have discovered that it is possible to do this safely, homogeneously, in a short time, or without infusibility treatment using oxygen, and also to form a large number of macro pores inside the granulated coal. .

The coal according to the present invention may be slightly caking coal, caking coal alone or a combination of non-caking coal and caking coal, etc., and is pulverized coal, preferably coal pulverized to a size smaller than 74 km. Good. Furthermore, if an activation yield of activated carbon with a specific surface area of 1400 m'/g or more is to be ensured at 30% or more, the grain size of the coal should be 10 gm or less.

On the other hand, the plants added are dried and crushed,
The particle size should be less than 1004m in average particle size.The degree of dryness of the plant is sufficient to be pulverized, but less than 5% is preferable.The addition of the plant is due to the generation of acidic gas and acidic liquid during the heating process. This is because the coal particles do not soften or melt, thereby preventing strong fusion between coal particles, and forming macropores in which the activation gas can easily diffuse into the interior of the carbide when activating the carbide.

The reason why the amount of plants added to coal was specified as 11% by weight or more and less than 50% by weight was because if it was less than 11% by weight, sufficient macropores could not be formed in the carbide, and the upper limit was set to be less than 50% by weight. This is because if it is added in an amount of 50% by weight or more, the mechanical strength of the granulated carbon decreases, pulverization occurs during the activated carbon manufacturing process, and the yield of activated carbon decreases significantly, making it uneconomical.

In order to form macropores that allow the activation gas to easily diffuse into the interior of the carbide during activation of the carbide, and to ensure sufficient mechanical strength of the granulated coal, the amount of plants added to the coal is preferably 15%. It is preferably at least 30% by weight.

It should be noted that if the average particle size of the crushed plants is 100 #Lm or more, the contact area with the coal will be too small and segregation of the plants will occur, which is not preferable.

Plants include grains, plants, bamboos, residues from extracting beneficial ingredients from plants (e.g. bakasu), and plants such as rice bran and bran produced during the refining of grains; It is particularly advantageous because it has a low moisture content when generated and is soft, making it easy to crush.

The mixed charcoal of crushed coal and plants is pressurized and formed into granulated coal, which is then carbonized in a carbonization furnace.

The particle size of the generated carbide must be adjusted according to the particle size of the target activated carbon. The particle size is preferably 5.0 to 0.3 cm. In addition, when oxidizing and carbonizing the granulated coal, a reaction method that allows the temperature of the granulated coal to be maintained at 100°C or higher and below 350°C is required. The granulated coal is charged into a container and oxidized with a mixed gas having an oxygen concentration of 1% by volume or more and less than 22% by volume.

The reason why granulated coal is oxidized using oxygen-containing gas is to quickly make the outer surface of the granulated coal infusible, prevent the granulated coal from fusion with each other, and speed up the infusibility of the coal. . In this case, the oxidation reaction is difficult to proceed below 100°C, and
This is because the oxidation reaction rapidly progresses and heat generation becomes intense at temperatures higher than 0.degree. C., making temperature control difficult and causing the caking coal to melt. Preferably the granulated coal temperature is 180°C or higher and 320°C
Less than that is better.

Further, the oxygen concentration of the oxygen-containing gas is suitably in the range of 1% by volume or more and less than 22% by volume. At oxygen concentration less than 1%,
The oxidation reaction is slow and it takes a long time to oxidize the granulated coal, making it uneconomical.If the oxidation reaction exceeds 22% by volume, the oxidation reaction progresses rapidly.
The temperature becomes high and temperature control becomes difficult.

When oxidizing granulated coal in this way, the oxygen concentration of the oxygen-containing gas, the temperature, and the heating conditions of the reaction vessel should be adjusted so that the temperature of the granulated coal in the reaction vessel is maintained at 100°C or more and less than 350°C. Although adjustment is necessary, in the present invention, the infusibility of coal progresses from within the granulated coal, so homogeneous infusible granulated coal is produced.

In addition, residual carbon from plants prevents coal particles from fusing together and forms pores suitable for adsorption.

The reaction vessel may be either a batch type or a continuous type such as a fluidized bed or a rotary furnace.

The granulated coal may be press-molded granulated coal as it is, but if the granulated coal is large, it should be crushed and sized before use.

The infusible granulated carbon is carbonized to about 700° C. by a conventional method, and then activated by a conventional method to produce activated carbon.

Note that if further mechanical strength is required, a binder such as tar pitch may be used.

As described above, the present invention facilitates the infusibility of coal and produces carbide by adding dried and finely ground plants to finely ground coal. It is activated with steam or a known method such as 002 to form activated carbon. Furthermore, in order to further accelerate the activation rate, it is recommended to add potassium and sodium, which are known inorganic compounds.

EXAMPLES Next, the present invention will be explained based on examples. Table 1 shows examples of the properties of coal and plants used in the method of the present invention.

Table 1 Example 1 70% by weight of coal pulverized to an average particle size of 32 gm and 30% by weight of grains pulverized to an average particle size of 29.7 Bm were mixed and pressure-molded to form granulated coal of 10 to 0.5 gm. did. 200g of this granulated coal was charged into a carbonization furnace with an internal volume of 400-2, and
The temperature was raised to 600° C. at a heating rate of 1.5 in, and after holding for 30 minutes, it was taken out to form a carbide.

The thus produced carbide was crushed and sized to a particle size of 3 to 0.51, 150g was charged into a reaction tube with a content fi of 2000, and activated at 900°C with a water vapor amount of 3g/+win for 5 hours to obtain activated carbon. . The yield of the produced activated carbon was 31%, and its specific surface area was 1410 rn''/g.

Example 2 80% by weight of coal pulverized to an average particle size of 32 pm and 20% by weight of bran pulverized to an average particle size of 80 pm were mixed and pressure-molded to obtain granulated coal of 10 to 0.5 m. 200g of this granulated coal was charged into a carbonization furnace with an internal volume of 400cm, and 2'C/w
The temperature was raised to 800° C. at a heating rate of 1.5 in, and after holding for 30 minutes, it was taken out to form a carbide.

This carbide was activated in the same manner as in Example 1 to obtain activated carbon. The yield of the generated activated carbon is 30%, and the specific surface area is 133.
It was 1rn''/g.

Example 3 70% by weight of coal pulverized to an average particle size of 321 Lm and 30% by weight of sawdust pulverized to an average particle size of 21.8 g, m were mixed and pressure-molded to obtain granulated coal of 10 to 0.5 cm. . 200g of this granulated coal was charged into a carbonization furnace with an internal volume of 3400.11,
Raise the temperature to 600℃ at a heating rate of 1.5℃/win,
After holding for 0 minutes, it was taken out and made into a carbide.

The thus produced carbide was crushed and sized to 3 to 0.5 mm, and 50 g was charged into a reaction tube with an internal volume of 2000 mm.
Activation was performed at 900° C. for 2 hours with a water vapor amount of 4 g/win to obtain activated carbon. The yield of the produced activated carbon was 28%, and its specific surface area was 1408 rrl'/g.

Example 4 70% by weight of coal pulverized to an average particle size of 4.5 pm and 30% by weight of rice bran pulverized to an average particle size of 17.8 g m were mixed and pressure-molded to form granules of 5 to 0.5 fat and fat. It was made into charcoal. 200g of this granulated coal was charged into a carbonization furnace with an internal volume of 3400, and
．． The temperature was raised to 600°C at a heating rate of 5°C/sin, and the temperature was increased to 30°C.
After fixing, it was taken out and made into a carbide.

The carbide generated in this way has an internal volume of 2 and 1508
000- reaction tube, and was activated at 800° C. with a water vapor amount of 7 g/in for 3 hours to obtain activated carbon. The yield of the produced activated carbon was 25%, and its specific surface area was 1508 g/g.

Example 5 60% by weight of coal pulverized to an average particle size of 32 gm and 40% by weight of rice bran pulverized to an average particle size of 21.5 μm were mixed, pressure-molded, crushed and sized to form a mixture of 5 to 0.51 gm. It was made into granulated charcoal. Content # of this granulated charcoal! 2 in a 13400J carbonization furnace
00g was charged, the temperature was raised to 800°C at a heating rate of 2°C/sin, and the temperature was maintained for 30 minutes.

Contents a2o of 150g of the carbide thus generated
The mixture was charged into reaction tubes oo and x, and activated at 900° C. with a water vapor amount of 4 g/ll1n for 3 hours to obtain activated carbon. The yield of the activated carbon produced is 30%, and its specific surface area is 15
It was 11rn'/g.

Example 6 70% by weight of coal pulverized to an average particle size of 3.2 pm and 30% by weight of grain pulverized to an average particle size of 29.7 m were mixed,
After being pressure-molded and agglomerated, it was sized to a size of 5 to 0.5 square centimeters to obtain granulated charcoal. This granulated coal was placed in a carbonization furnace with an internal volume of 200 m
280 g using a mixed gas with an oxygen concentration of 6% by volume.
After 301n of oxidation treatment at °C, the temperature was raised to 600 °C at a heating rate of 2.5 °C/win, and after holding for 30 minutes, it was taken out and made into a carbide.

The thus produced carbide was sized to a size of 3 to 0.5H, and 150 g of it was charged into a reaction tube with an internal volume of 2000 cm.

Activation was carried out at 900° C. for 2.5 hours with a water vapor amount of 4 g/win to obtain activated carbon. The yield of the generated activated carbon was 30%, and its specific surface area was 1511rrf/g.

Example 7 85% by weight of coal A pulverized to an average particle size of 3.2 gm and 15% by weight of rice bran pulverized to an average particle size of 27.8 μm were mixed and pressure-molded to obtain granulated coal of 5 to 0.5 mm.

200g of this granulated coal was charged into a carbonization furnace with an internal volume of 3400, and heated at 280°C using a mixed gas with an oxygen concentration of 8% by volume.
After 80ml of oxidation treatment, the temperature was raised to 700°C at a heating rate of 2°C/sin, and after holding for 30 minutes, it was taken out to form a carbide.

The carbide produced in this way was sized to a grain size of 3 to 0.5, and 100 g was charged into a reaction tube with an internal volume of 2000 cm.
Activation was performed at 900° C. for 3 hours with a water vapor amount of 4 g/mid to obtain activated carbon. The yield of the produced activated carbon was 35%, and its specific surface area was 1521 g/g.

Example 8 65% by weight of coal pulverized to an average particle size of 3.2 gm and 35% by weight of wheat bran pulverized to an average particle size of 9.3 gm were mixed,
After being pressure-molded and agglomerated, it was crushed and sized to a size of 5 to 0.5 square centimeters to obtain granulated charcoal. This granulated coal was charged into a carbonization furnace with an internal volume of 3,400 cm, and after being oxidized at 180 °C for 180 sin using a mixed gas with an oxygen concentration of 21 volume%, it was heated at 2 °C/
The temperature was raised to 700° C. at a heating rate of 30° C., and after holding for 30 minutes, it was taken out to form a carbide.

The carbide produced in this way was sized to a size of 3 to 0.5 mm, and 100 g was charged into a reaction tube with an internal volume of 2000 mm.
Activation was performed at 900°C for 3 hours with a water vapor amount of 4 g/sin to obtain activated carbon. The yield of the produced activated carbon was 34%, and its specific surface area was 1480 rn''/g.

Example 9 80% by weight of coal pulverized to an average particle size of 324 m and 20% by weight of sawdust pulverized to an average particle size of 111.11 μm were mixed, pressure-molded to agglomerate, and then crushed to a height of 5 to 0.5 m. It was sized and made into granulated charcoal. 300g of this granulated coal was charged into a carbonization furnace with an internal volume of 3400all, and after being oxidized at 120°C for 240 sin using a mixed gas with an oxygen concentration of 15% by volume, it was heated to 600°C at a heating rate of 2°C/win. Raise the temperature to 30
After fixing, it was taken out and made into a carbide.

The carbide thus produced was sized to a weight of 3 to 0.5, and 150 g was charged into a reaction tube with a content of 2000 J.
Activation was performed at 900° C. for 4 hours with a water vapor amount of 4 g/sin to obtain activated carbon. The yield of activated carbon produced was 32%,
Its specific surface area was 1310rn'/g.

Example 10 85% by weight of coal pulverized to an average particle size of 32pm and 20% by weight of sawdust pulverized to an average particle size of 1!3.9 JJ-m were mixed, pressure-molded and agglomerated, and then 5-0. The charcoal was crushed and granulated into granulated charcoal. This granulated charcoal content! ll3400-
After charging 300g into a carbonization furnace and oxidizing it for 30 inches at 300℃ using a mixed gas with an oxygen concentration of 8% by volume, it was heated to 2℃.
The temperature was raised to 600°C at a heating rate of /sin, and after holding for 30 minutes, it was taken out to form a carbide.

The carbide produced in this way was sized to a particle size of 3 to 0.511, and 150 g was charged into a reaction tube with an internal volume of 2000 cm.
Activation was performed at 900° C. for 4 hours with a water vapor amount of 4 g/sin to obtain activated carbon. The yield of activated carbon produced was 40%,
Its specific surface area was 1290 m'/g.

Example 11 80% by weight of coal pulverized to an average particle size of 32#Lm and 20% by weight of bamboo pulverized to an average particle size of 18.2gm were mixed, pressure-molded and agglomerated, and then mixed into 5-0.51 gm. It was sized and made into granulated charcoal. This granulated coal was placed in a carbonization furnace with an internal volume of 3,400 cm.
8 charges, using a mixed gas with an oxygen concentration of 3% by volume, 30
After 120ml of oxidation treatment at 0°C, the temperature was raised to 80Q°C at a heating rate of 3°C/win, and after holding for 30 minutes, it was taken out to form a carbide.

The carbide thus produced was sized into a 3-0.5+s layer, and 200 g was charged into a reaction tube with an internal volume of 2000 sq.
Activation was carried out at 900° C. for 4 hours with water vapor fit 7 g/win to obtain activated carbon. The yield of the produced activated carbon was 40%, and its specific surface area was 1390 m''/g.

Comparative Example 1 92% by weight of coal pulverized to an average particle size of 32 gm and 8% by weight of sawdust pulverized to an average particle size of 27.8 pm were mixed, pressure molded and agglomerated, and then 5 to 0.5 gm The coal was sized into layers and made into granulated charcoal. This granulated coal was placed in a carbonization furnace with an internal volume of 3400
0g was charged, and the temperature was raised to 600°C at a heating rate of 2°C/win, and after holding for 30 minutes, it was taken out and made into a carbide.

The thus generated carbide was sized to a size of 3 to 0.5 mm, and 50 g was charged into a reaction tube with a content of 2000 all.
Activation was performed at 900° C. for 4 hours with a water vapor amount of 4 g/win to obtain activated carbon. The yield of activated carbon produced is 30%,
The specific surface area was 980rn''/g, which was small. Comparative Example 2 45% by weight of coal pulverized to an average particle size of 32.0 μm and 55% by weight of rice bran pulverized to an average particle size of 17.8 m layer,
After being pressure-molded and agglomerated, the charcoal was sized to a particle size of 5 to 0.51 to obtain granulated charcoal. This granulated coal was placed in a carbonization furnace with an internal volume of 3,400 mm.
008 and heated to 600°C at a heating rate of 1.5°C/in.
After holding for 30 minutes, the mixture was taken out to form a carbide.

The carbide produced in this way was sized into 3 to 0.5 layers, and 50 g was charged into a reaction tube with an internal volume of 2000 cm.
Activation was carried out at 0°C for 3 hours with a water vapor amount of 4 g/mid to obtain activated carbon. The generated activated carbon was powdered and could not be turned into granular activated carbon.

Comparative Example 3 80% by weight of coal pulverized to an average particle size of 33.2) hm and 20% by weight of sawdust pulverized to an average particle size of 21.8 layer m were mixed, pressure-molded and agglomerated, and then 5-0. The charcoal was sized to a particle size of 51 mm and used as granulated charcoal. This granulated coal was placed in a carbonization furnace with an internal volume of 3,400 mm.
00g and using a mixed gas with an oxygen concentration of 8% by volume.
An attempt was made to oxidize the coal at 10°C, but the coal softened and melted and could not become granular carbide.

Effects of the Invention As shown in Examples and Comparative Examples, the method of the present invention,
That is, by adding 11% by weight or more and less than 50% by weight of pulverized plants to pulverized coal, a carbide for activated carbon can be easily produced.

The activated carbon produced from the carbide of the method of the invention can be used as activated carbon for water treatment, solvent adsorption, gasoline, or as a deodorizing agent.

Claims (3)

[Claims] (1) It is characterized by adding 11% or more and less than 50% by weight of pulverized plants to pulverized coal, pressurizing it to form granulated coal, carbonizing it in a carbonization furnace, sizing it, and then activating it. Method for producing activated carbon. (2) After adding 11% by weight or more and less than 50% by weight of pulverized plants to pulverized coal, the granulated coal is formed by pressure, and then carbonized in a carbonization furnace as it is or after sizing, and then activated. A method for producing activated carbon characterized by: (3) After adding 11% or more and less than 50% by weight of crushed plants to the crushed coal, pressurize it to make granulated coal, either as it is or after sizing it to make granulated coal, oxidize this granulated coal. 1. A method for producing activated carbon, which comprises performing an oxidation treatment at 100° C. or higher and lower than 350° C. using a reactive gas, followed by carbonization activation.