JP2003183667A - Method for producing activated carbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing activated carbon, by which the activated carbon having the same strength and performance as those of activated carbon produced from coal can stably be produced at a low cost from organic wastes such as waste wood, waste bamboo, waste paper, crushed corn cores or used plastics. <P>SOLUTION: This method for producing the activated carbon, comprising a pre-carbonizing process for pre-carbonizing the organic wastes, a kneading and molding process for kneading and molding the pre-carbonization product obtained in the pre-carbonizing process, and a carbonizing process for carbonizing the molded products obtained in the kneading and molding process, is characterized by mixing and kneading the pre-carbonization product obtained in the pre-carbonizing process with water, mixing and kneading the product with a binder, and then molding the product with a double roll molding machine, in the kneading and molding process. Therein, the binder is preferably added in an amount of 18 to 42 pts.wt. per 100 pts.wt. of the carbonization product, and the water is also preferably added in an amount of 15 to 35 pts.wt. per 100 pts.wt. of the total amount of the carbonization product and the binder added to the carbonization product. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to waste wood, waste bamboo material,
The present invention relates to a method for producing activated carbon from organic wastes such as waste paper, crushed corn cores, and used plastics as raw materials.

[0002]

2. Description of the Related Art Dry desulfurization and denitration equipment is widely used as a method for removing sulfur oxides and nitrogen oxides from various exhaust gases containing sulfur oxides and nitrogen oxides. A variety of adsorbents and catalysts are used in this dry desulfurization and denitration equipment.In particular, carbonaceous adsorbents have excellent adsorption ability for sulfur oxides and performance as a reduction decomposition catalyst for nitrogen oxides. Coke is widely used as a carbonaceous adsorbent for desulfurization and denitration.

Many methods for producing activated carbon or activated coke from coal have been proposed. For example, in Japanese Examined Patent Publication No. 2-48294, a semi-coke is produced from coal, a binder is added to the coke so that the Loga index falls within a predetermined range, the coke is molded, and the molded product is dry-distilled and then treated with sulfuric acid. A method of producing a shaped activated coke is disclosed. In Japanese Patent Laid-Open No. 5-105415, semi-coke produced by preliminary carbonization in which oxygen concentration and temperature are adjusted to a predetermined range is used as a main raw material, and caking coal is added to the semi-coke to form the coke.
A method for producing a molded active coke by dry distillation of the obtained molded product is disclosed. Japanese Unexamined Patent Publication No. 10-296078 discloses a method for producing activated coke by forming a mixed coal having a two-layer structure in which coal powder is adhered to the surface layer of coke and press-molding the mixed coal.

A technique for producing activated carbon from waste as a raw material is also disclosed. For example, Japanese Patent Publication No. 6-69883 discloses carbonizing a crushed wood piece and adding water and a binder to the obtained carbonized material. A molecular sieve carbon material produced by dry-distilling after molding a kneaded product is disclosed.
Further, Japanese Patent Application Laid-Open No. 9-53085 discloses a method for producing activated carbon by carbonizing a solid material obtained by crushing and molding municipal solid waste.

[0005]

However, the techniques disclosed in JP-B-2-48294, JP-A-5-105415, and JP-A-10-296078 use coal as a raw material, so that activated carbon and The production cost of activated coke is high, and there is a problem that enormous running cost is required when used for exhaust gas treatment equipment, wastewater treatment equipment and the like.

On the other hand, in Japanese Unexamined Patent Publication No. 9-53085, waste is used as a raw material, and thus activated carbon produced is relatively inexpensive, but in the same Japanese publication, the activity (specific surface area) is increased. Therefore, during or after carbonization, it is necessary to perform activation such as addition of steam to the carbide, which complicates the manufacturing process and raises the cost of manufacturing activated carbon.

In the method for producing activated carbon disclosed in Japanese Patent Publication No. 6-69883, it is necessary to finely pulverize the raw material carbide in the kneading step before forming, and to add water to the raw material carbide. However, it requires additional treatment steps such as pre-drying after molding, which necessitates an increase in manufacturing cost and does not necessarily have the advantage of using inexpensive raw materials. Further, it does not describe anything about the purpose or effect of adding water to the raw material carbide.

The present invention has been made in view of such circumstances, and an object thereof is to dispose of organic waste such as waste wood, waste bamboo, waste paper, crushed corn cores, and used plastics. It is an object of the present invention to provide a method for inexpensively and stably producing activated carbon which is used as a raw material and has strength and performance equivalent to those of activated carbon made from coal.

[0009]

Means for Solving the Problems The present inventors have proposed a preliminary carbonization step of carbonizing organic waste by preliminary carbonization, a kneading / molding step of kneading and molding the obtained carbide, and this molded article. In the method of producing activated carbon by the dry distillation step of dry distillation, the inventors have earnestly studied to solve the above problems. As a result, the following findings were obtained. That is, in the kneading / molding step, not only a binder is added to the carbide obtained by preliminary dry distillation, but also water is added and kneaded,
It was found that the strength and specific surface area of activated carbon can be improved. The examination results will be described below.

When a carbide obtained by preliminary carbonization (hereinafter also referred to as "preliminary carbonization carbide") is molded by using a double roll molding machine, water is added to the preliminary carbonization carbide so that the roll pressure can be efficiently applied to the object to be molded. I can communicate well. Therefore, the addition of water prevents repulsive cracking of the molded product due to the molding pressure, and a double roll molding machine can obtain a molded product having a high cold strength with a relatively low molding pressure.

Further, the addition of water plays a role of protecting the high specific surface area of the preliminary carbonization carbide, but in order to obtain the effect, the order of addition of the binder and water is extremely important. In order to protect the pores of the preliminary carbonization carbide from being blocked, in the kneading / molding process, water is first added to impregnate the pores of the preliminary carbonization carbide with water by a capillary phenomenon,
It is important to add the required amount of binder. That is, it is important to fill the pores with water to prevent the binder from entering the pores. At this time, the addition of water is a means for preventing pore clogging, and the specific surface area of the product carbonized product thus produced is equal to or slightly lower than that of the preliminary carbonization carbonized product. The properties of carbide are fully utilized.

As described above, it was found that the addition of water at the time of molding by the double roll molding machine has a great influence on the moldability such as the control of the molding pressure and the strength of the molded product.

In this case, the amount of the binder added is preferably 18 to 42 parts by weight with respect to 100 parts by weight of the preliminary carbonized carbide. If it is less than 18 parts by weight, it cannot be expected to improve the cold strength after molding and the carbide product strength after carbonization.
On the other hand, if it exceeds 42 parts by weight, the mold release from the roll becomes poor, and a good quality molded product cannot be obtained. The amount of water added is
The amount is preferably 15 to 35 parts by weight with respect to 100 parts by weight of the raw material obtained by adding the binder to the preliminary dry-distilled carbide.
If it is less than 15 parts by weight, it will be difficult to control the molding pressure and the molded product will frequently undergo repulsive cracking. On the other hand, if it is more than 35 parts by weight, the repulsive cracking will disappear, but the strength of the molded product will weaken and it will rapidly decrease in the post-drying process Bursting may occur due to evaporation of various moisture.

The present invention has been made on the basis of the above-mentioned examination results, and the method for producing activated carbon according to the first invention comprises a preliminary carbonization step of preliminary carbonization of organic waste and a charcoal product obtained in the preliminary carbonization step. A method for producing activated carbon by a kneading / molding step of kneading and molding, and a carbonization step of carbonizing the molded product obtained in the kneading / molding step, wherein the kneading / molding step is performed in a preliminary carbonization step. Characterized by adding water to the carbide and kneading, then adding a binder and kneading, and then molding with a double roll molding machine,
The method for producing activated carbon according to the second invention is characterized in that, in the first invention, the addition amount of the binder is 18 to 42 parts by weight with respect to 100 parts by weight of the carbide obtained in the preliminary carbonization step. The method for producing activated carbon according to the third invention is the method according to the first invention or the second invention, wherein the addition amount of water is the total of the carbide obtained in the preliminary carbonization step and the binder added to the carbide. It is characterized by being 15 to 35 parts by weight with respect to 100 parts by weight of the raw material.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The organic waste used in the present invention is waste wood,
Examples include waste bamboo materials, waste paper, crushed corn cores, and used plastics. In the present invention, used organic waste is used as the raw material, but it goes without saying that the unused waste can be used as the raw material.

The preliminary carbonization treatment in the preliminary carbonization process is basically carried out in an inert atmosphere. In the method of the present invention, oxygen may be present during preliminary carbonization, but the combustion of carbonaceous matter is controlled by treating in an inert atmosphere, and as a result, the yield of the preliminary carbonization carbide and the content of carbonization in the preliminary carbonization carbide are reduced. Preliminary carbonization in an inert atmosphere is preferable because the ratio of carbonaceous matter can be increased. Further, by preliminary carbonization in an inert atmosphere, it is possible to suppress the production of dioxins.
As described above, the atmosphere during the preliminary carbonization is preferably a non-oxidizing inert gas atmosphere, but an atmosphere with a low oxygen concentration of 8% or less can also be used. However, since the oxygen concentration in the atmosphere and the preliminary dry distillation yield have a contradictory relationship, it is desirable to dry-distill in an atmosphere having an oxygen concentration of 5% or less when performing in an oxygen-containing atmosphere.

Preliminary carbonization is performed by preliminarily carbonization of organic waste such as waste wood, waste bamboo, waste paper, corn core crushed products, used plastics, etc. The specific surface area is 150 m ² / g.
Dry distillation under the above-mentioned dry distillation conditions. This dry distillation condition depends on the type of organic waste and the type of dry distillation equipment.
It is preferable to conduct a test under individual conditions in advance and to grasp the dry distillation conditions that satisfy the conditions. 150m when used alone
^The organic waste that cannot obtain a specific surface area of ² / g or more is mixed with the organic waste that can obtain a high specific surface area so that the specific surface area becomes about 150 m ² / g or more, and It is preferable to use as.

The organic waste to be subjected to preliminary dry distillation has a diameter of 10 mm due to crushing or the like in order to minimize variations in dry distillation conditions due to differences in water content and volatile matter of the organic waste.
The length is preferably 50 mm or less, and more preferably the diameter is 5 mm and the length is 30 mm or less. With a particle diameter of 10 mm or more and a length of 50 mm or more, dry distillation may be insufficient depending on the type of organic waste, and the target specific surface area of 150 m ² / g or more cannot be obtained. However, if the finely pulverized material occupies the majority of the pre-distilled carbide, a large amount of binder needs to be added at the time of kneading in the subsequent step, which causes an increase in manufacturing cost, which is not preferable.

A general industrial furnace can be used as the dry distillation furnace used for the preliminary dry distillation treatment. For example, an internal heat type or external heat type rotary kiln, a fluidized bed furnace, a coke oven, a continuous carbonization furnace, a batch carbonization furnace, etc. may be used.

The preliminary carbonization carbide having a high specific surface area obtained by the preliminary carbonization is cooled in an inert atmosphere, and then kneaded / kneaded in the next step.
Transferred to the molding process. A general kneader can be used for kneading, but it is preferable to use a double jacket type high-speed rotary kneader capable of heating with heated steam. The preliminary dry-distilled carbide charged into the high-speed rotary kneader is conditioned by steam, and after a predetermined amount of water is added and stirred,
A predetermined amount of binder is added and stirred at high speed. In this case, the binder is added after the added water is almost uniformly dispersed in the preliminary carbonized carbide by stirring after the addition of water.

As described above, the amount of water added is 15 with respect to 100 parts by weight of the raw material, which is the total of the carbide obtained in the preliminary carbonization step and the binder to be added to this carbide.
To 35 parts by weight, particularly preferably 20 to 30 parts by weight, and the addition amount of the binder is preferably 18 to 42 parts by weight with respect to 100 parts by weight of the preliminary carbonization carbide. In particular, it is desirable that the amount is 22 to 38 parts by weight.

By adding a binder to the preliminary carbonization carbide, not only the cold strength after molding is improved, but also
It is also possible to improve the strength of the carbide product after carbonization. Examples of binders include cement as an inorganic binder, and as an organic binder,
Examples include coal tar-based heavy oil, pitch, coal liquefied oil, petroleum-based vacuum residual oil from a specific oil system, ethylene bottom oil, and reformed oil. Any of these oils or a mixture thereof may be used.

After the kneading is completed, it is molded by a double roll molding machine. The molding shape is a Macek type, an egg type, a stamped type or the like depending on the intended use.

Then, the molded product is conveyed to the next dry distillation process and carbonized by a dry distillation treatment in a dry distillation furnace. The dry distillation temperature is preferably 600 ° C to 1000 ° C. 600
At temperatures below ℃, volatile components remain, which adversely affects the strength and properties of the product carbide. Further, at a carbonization temperature of 1000 ° C. or higher, a phenomenon occurs in which the specific surface area of preliminary carbonized carbon such as waste wood and waste bamboo material becomes small, which adversely affects the adsorption capacity. The residence time at the target carbonization temperature can be appropriately determined according to the type of raw material, product performance, and the like.

By producing activated carbon from organic waste as described above, activated carbon having strength and quality equivalent to activated carbon produced from coal as a raw material can be produced inexpensively and stably. .

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples. Using the production method according to the present invention, activated carbon was produced using waste wood, waste bamboo, corn core pulverized material, and used plastic as raw materials.

FIG. 1 shows a schematic diagram of the production flow of the activated carbon used in this example. Waste is taken out from the waste wood / waste paper waste pit 1 and the used plastics waste pit 2 at a predetermined ratio, put into the disintegrator 3, pass through the disintegrator 4, and then conveyed by the belt conveyor 5 on the way. , Magnetic separator 6
To remove the magnetic substance. After that, wind power sorter 7
After removing the non-magnetic metal and other heavy materials through the separator, the granules were passed through the separator 8 and the storage tank 9 and molded into a predetermined solid size. The molded solid material A is conveyed to the solid material receiving hopper 11 by the belt conveyor 25. The solid material receiving hopper 11 can store a predetermined amount.

The solid A thus obtained was fed to a preliminary carbonization furnace 12 consisting of a rotary kiln. The preliminarily carbonized carbide thus obtained is simply crushed by a crusher 13 to be sized, and a wind force sorter 14
After removing non-ferrous and metal again, it was conveyed to the weighing hopper 17 by the belt conveyor 26 through the sieve 15.
Then, it was sent to the high-speed rotary kneader 18 by the belt conveyor 27, where it was sufficiently mixed with water supplied from the water tank 29, and then sufficiently mixed with the binder supplied from the binder tank 19. After the mixture was molded by the double roll molding machine 20, the powdery material was removed by the sieve 21. The preliminarily carbonized carbide having a large particle size removed by the sieve 15 is again sent to the crusher 13 to be sized.
When the waste plastics waste is not blended in a predetermined ratio, the non-magnetic metal and other heavy substances are removed through the wind separator 7, and then the separator 8, the storage tank 9 and the granulator 10 are used. It can be directly supplied to the preliminary carbonization furnace 12 without passing through.

The obtained molded product B was dry-distilled in a dry-distilling furnace 22 composed of a rotary kiln. After the dry distillation product was cooled to a predetermined temperature by the product cooler 23 and the cooling tower 24, the target activated carbon 28 was obtained. The powdery material C generated in the dry distillation furnace 22 and the product cooler 23 is sent to the recycled powder hopper 16 and used as a raw material for molding.

In Table 1, the preliminary dry-distilled carbides obtained by preliminary dry-distillation in a nonoxidizing atmosphere are
6 mm x 16 mm x 8 mm Macek type and 16 mm x
The test results were obtained by molding the product into an egg shape of 12 mm to 8 mm, and dry-distilling the molded product under conditions of a dry distillation temperature of 850 ° C., an effective residence time of 60 minutes and a non-oxidizing atmosphere, a total of 11 times.

[0032]

[Table 1]

The water addition amount shown in Table 1 is the addition amount with respect to 100 parts by weight of the raw material, which is the total of the carbide obtained in the preliminary carbonization step and the binder to be added to this carbide, and the binder addition amount is The amount of addition to 100 parts by weight of the carbide obtained in the preliminary dry distillation step, and the formability of the preliminary dry distillation carbide was determined by visually observing the formability in a double roll forming machine in four stages (excellent: ◎-○-△ -x: Inferior). Also, the DI strength is obtained by sieving the product with 8 mm,
5mm product on 8mm diameter 500mm, length 500m
It was displayed in the residual rate (percentage) on 4 mm after 300 rpm (25 rpm) loading in a trommel of m.
Comprehensive evaluation has four grades (excellent:
⊚- ○ -Δ-x: Inferior).

In Test Nos. 1 to 6, when the preliminary dry-distilled carbide was kneaded, the water was previously adjusted to 23 parts by weight with respect to 100 parts by weight of the total of the preliminary dry-distilled carbide and the binder to be added to the carbide. Thus, 25 parts by weight of the binder was added to 100 parts by weight of the preliminary carbonized carbide, and the mixture was stirred at a high speed, molded by a double roll molding machine, and then carbonized. For waste wood / plastic and waste bamboo / plastic, each individual raw material is made into a predetermined particle size, and it is used as a raw material for preliminary carbonization that is formed into a columnar shape with a diameter of 15 mm and a length of 30 to 50 mm using a twin-screw extruder. did.

Test Nos. 7 and 8 were prepared by the same method as Test No. 1 except that the amount of water added was 10 parts by weight and 40 parts by weight, respectively, at the time of kneading the preliminary dry-distilled carbide. Nos. 9 and 10 are for kneading the preliminary carbonized carbide,
The amount of binder added was 12 parts by weight and 44 parts by weight, respectively. Other than that, it was manufactured by the same method as Test No. 1. In Test No. 11, the amount of water and binder added was the same as in Test No. 1. However, the order of addition is that the binder is added in advance and then water is added.

As is clear from Table 1, in Test Nos. 1 to 6 in which the amounts of water and the binder added were adjusted to the optimum ranges, it was found that the predrying carbonization product had good moldability and product properties. . On the other hand, in Tests 7 to 9 in which the addition amount of water or the binder was out of the preferable range, the moldability or the product properties were slightly inferior, but it was possible to sufficiently use the activated carbon. However, in Test No. 10 in which the binder was added in a large amount and in Test No. 11 in which the addition order of water and the binder was reversed, the specific surface area was small and it was insufficient as activated carbon. It was also found that it is necessary to carry out activation such as addition of steam.

[0037]

As described above, according to the present invention, coal is used as a raw material from waste wood, waste bamboo, waste paper, crushed corn core, used plastics and other organic wastes. It is possible to inexpensively and stably manufacture activated carbon having strength and performance equivalent to that of activated carbon, which brings beneficial effects in industry.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic view of a production flow of activated carbon used in this example.

[Explanation of symbols]

1 Waste wood / waste paper waste pit 2 Used plastic waste pit 3 crusher 4 crusher 5 belt conveyor 6 magnetic separator 7 Wind power sorter 8 separator 9 storage tanks 10 granulator 11 Solid receiving hopper 12 Preliminary carbonization furnace 13 crusher 14 Wind sorting machine 15 sieve 16 Recycled powder hopper 17 Weighing hopper 18 High-speed rotary kneader 19 binder tank 20 double roll forming machine 21 sieve 22 Dry distillation furnace 23 Product Cooler 24 cooling tower 25 belt conveyor 26 Belt conveyor 27 Belt conveyor 28 activated carbon 29 Water tank A solid B molding C powder

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshihiko Okada             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Tatsuro Ariyama             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Kazumasa Wakimoto             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Hirokatsu Masuoka             Hiroshima Prefecture Higashihiroshima City 1-4-1 Kagamiyama Hiroshima             University Graduate School of Engineering F-term (reference) 4H012 HA03 HB03 JA03 KA01 KA03                       KA04 KA05

Claims (3)

[Claims] 1. A preliminary dry distillation step of preliminary dry distillation of organic waste, a kneading / molding step of kneading and molding the carbide obtained in the preliminary dry distillation step, and a dry distillation of the molded article obtained in the kneading / molding step. In the kneading / forming step, water is added to the charcoal-based material obtained in the preliminary carbonization step to knead, and then a binder is added to knead the kneading / forming step. A method for producing activated carbon, characterized in that it is formed by a double roll forming machine. 2. The method for producing activated carbon according to claim 1, wherein the amount of the binder added is 18 to 42 parts by weight with respect to 100 parts by weight of the carbide obtained in the preliminary carbonization step. 3. The amount of water added is 15 to 35 parts by weight with respect to 100 parts by weight of the raw material, which is the total of the carbide obtained in the preliminary carbonization step and the binder added to the carbide. The method for producing the activated carbon according to claim 1 or 2.