JP2003292318A - Method for manufacturing activated carbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing activated carbon by co- carbonization method for improving a yield of the activated carbon by activating carbonization of plastics. <P>SOLUTION: The method for manufacturing the activated carbon is characterized in that the activated carbon is obtained by carbonizing combustible waste which is added with the plastics beforehand with a predetermined rate so as to co-carbonize them. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing activated carbon using combustible waste.

[0002]

2. Description of the Related Art A number of technologies for producing activated carbon from combustible wastes have been proposed. For example, as a raw material, okara, kitchen waste, sludge, waste paper, etc. have been proposed. For example, Japanese Patent Application Laid-Open No. 7-242406 describes a method for producing a carbonaceous substance from papers. This technology is a technology to obtain carbonaceous substances by heating paper such as waste paper in a cotton shape or cutting and then heating in anoxic state, and it is stated that this carbonaceous substance can also be used as an adsorbent. .

However, the conventional dry distillation method for heating combustible waste in an oxygen-free state has a problem that the yield of activated carbon obtained is low and the specific surface area of activated carbon is small, so that the adsorptivity is low. It was Generally, when the specific surface area is increased to improve the adsorption performance of activated carbon, the yield of activated carbon raw material is reduced and the yield of activated carbon is reduced. In particular, plastics, which is a type of combustible waste, has a problem that the amount of carbon remaining after dry distillation is small and the activated carbon yield is low because it volatilizes during dry distillation.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing activated carbon by co-carbonization, which promotes carbonization of plastics and improves the yield of activated carbon.

[0005]

[Means for Solving the Problems] In order to solve the above problems, as a result of intensive studies by the present inventors, as a result of combustible wastes such as wood and / or paper, instead of carbonizing plastics alone. It was found that carbonization of plastics is promoted by adding plastics and performing carbonization. That is, when combustible waste (generally an organic hydrocarbon compound) and plastics (generally synthetic resins) are mixed at a fixed ratio and subjected to carbonization, carbonization of the plastics is promoted due to the co-carbonization phenomenon described later. It is possible to achieve a high yield, which cannot be obtained by the dry distillation method.

The term "organic hydrocarbon compound" as used herein means, for example, when carbonized alone at a carbonization temperature of 300 ° C to 800 ° C.
Fixed carbon contained after dry distillation is 10% by weight or more. In addition, the synthetic resins refer to those having a fixed carbon content of 5% by weight or less when dry-distilled alone under the same dry-distillation conditions. And, as described above, it indicates a substance that causes a co-carbonization phenomenon when both are dry-distilled together.

That is, according to the present invention, there is provided a method for producing activated carbon, which comprises adding synthetic resins to an organic hydrocarbon compound and then subjecting it to carbonization by dry distillation.

Further, according to the present invention, there is provided a method for producing activated carbon, characterized in that plastics are added to a combustible waste in a predetermined ratio, and then carbonized by carbonization by dry distillation.

In the present invention, it is preferable that the combustible waste is solidified waste.

In the present invention, the combustible waste is preferably wood and / or paper.

Further, in the present invention, the combustible waste is
The crushed corn core and food waste such as coffee grounds are preferred.

Further, in the present invention, it is preferable to add plastics in an amount of 5 to 50% by weight based on the total weight.

Further, in the present invention, it is preferable to add plastics in an amount of 5 to 30% by weight based on the total weight.

Further, in the present invention, it is preferable that the plastics are added to the combustible waste and then mixed before the carbonization.

Further, in the present invention, it is preferable to carry out two-stage dry distillation in the dry distillation process.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The flammable waste used in the present invention includes woods (including bamboo), papers such as waste paper, plastics and the like. Further, combustible waste also includes crushed corn cores used as culture soil for mushrooms and the like, and food waste such as coffee grounds. Other than plastics, simple substances can be used as raw materials, but they can also be used as a mixture.

Particularly, as combustible waste, solidified waste such as solid waste fuel (RDF: Refuse De
It is preferable to use rived fuel). RDF is composed of combustibles and incombustibles. The combustibles are mainly wood, papers, and plastics, and the incombustibles are metals, sands, and the like. The ratio of the combustible component to the non-combustible component largely depends on the type of RDF (quality of the raw material waste), but since the combustible component is used in the present invention, it is preferable to use RDF containing a large amount of the combustible component as the raw material. RD that solidifies general waste and industrial waste
The size of F is large, from 30 mm in diameter, to small, about 5 mm in columnar shape, and is excellent in storability and transportability. Also, the problem of odor can be solved by adding limes in the manufacturing process. The crushed corn core of food waste and the coffee slag itself are coarsely crushed themselves, so there is no need to granulate them in advance, but they contain a lot of water, so to some extent before they are subjected to carbonization treatment,
Carbonization proceeds more efficiently when water is removed. Further, if a mixture having a relatively stable quality is used as a raw material, activated carbon having a stable performance can be easily manufactured.

Plastics are added to the above flammable wastes in a predetermined ratio. Alternatively, after separating combustible waste into wood, paper, plastics, etc., or individually separating wood, paper, plastics, etc. Add in ratio. Then, preferably, they are uniformly mixed to obtain a raw material for dry distillation. Specifically, for example, combustible waste and plastics are put in a crusher at a predetermined ratio and crushed, crushed by a crusher, and then molded into a certain size by a granulator for dry distillation. Use as raw material.

When flammable wastes for which a high specific surface area cannot be expected are used as raw materials for the activated carbon after carbonization treatment, such a combustible waste and a high specific surface area due to carbonization treatment such as wood or paper are used. It can be used as a mixture with expected flammable waste. When mixing, the mixing ratio is adjusted so that the target specific surface area of activated carbon is obtained.
Then, plastics can be added to the obtained mixture at a predetermined ratio.

The upper limit of the amount of plastics added is determined so that the specific surface area of the resulting activated carbon is not impaired. For example, when the main raw material is paper, it is preferable that the content of plastics is 5 to 30% by weight, and more preferably 10 to 25% by weight. Or papers: plastics g = 95: 5-7
It is preferable to add it in an amount of 0:30 (% by weight), and more preferably papers: plastics = 90: 10.
˜75: 25 (wt%).

When the main raw material is wood, it is preferable that the content of plastics is 5 to 50% by weight, and more preferably 10 to 45% by weight. Or wood: plastics = 95: 5
It is preferable to add it in an amount of about 50:50 (wt%), more preferably wood: plastics = 90:
It is added so as to be 10 to 55:45 (% by weight).

If the proportion of plastics is less than 5% by weight, the amount of carbides remaining after dry distillation is the same as in the case of only combustible wastes, and the effect of adding plastics is low, so crushing after addition, The crushing process is wasted. Also,
When the main raw material is paper, the ratio of plastics exceeds 30% by weight, and when the main raw material is wood, when the ratio of plastics exceeds 50% by weight, the specific surface area of carbides may be small. As a result, the properties of the final product, activated carbon, deteriorate. Thus, when mixing the combustible waste and the plastics, it is important to mix them in a predetermined ratio.

By mixing plastics with the combustible waste and dry-distilling them together, a co-carbonization phenomenon occurs during the dry-distillation, and the amount of the carbon and the ratio of the carbonaceous matter in the carbon are compared with the case where each of them is carbonized alone. Can be higher. The co-carbonization phenomenon means that carbon compounds (plastics, oil, etc.) gasified by the temperature rising process such as carbonization contact solid carbon (carbon generated from combustible wastes) in the carbonization atmosphere, and It is a phenomenon of crystallization. As a result of this phenomenon, carbonization of plastics that are difficult to carbonize is promoted because they are gasified and volatilized when they are carbonized alone. As described above, by using the co-carbonization phenomenon in the carbonization process, it is possible to achieve a high yield that cannot be obtained by the ordinary carbonization method. This co-carbonization phenomenon is more effective when the plastics and the combustible waste are adjacent to each other, and the plastics and the combustible waste are molded into a certain size with a granulator or the like, and then dried. It can be a raw material. Further, by granulating, it is possible to suppress adhesion of plastics to the furnace wall and clogging of raw materials during dry distillation in a rotary kiln.

The mixture of combustible waste and plastics produced as described above is subjected to dry distillation to produce activated carbon. The dry distillation is preferably a two-stage dry distillation including preliminary dry distillation. The co-carbonization phenomenon in the present invention occurs during the first stage preliminary carbonization. The two-stage carbonization will be described below, but it goes without saying that the activated carbon can be produced only by the second carbonization without the preliminary carbonization.

In the two-stage dry distillation, the raw material mixture is preliminarily dry-distilled at a temperature of 300 to 800 ° C., and then the second dry distillation is further performed at a temperature of 600 to 1000 ° C., for example.

Both the preliminary dry distillation and the second dry distillation are carried out in an inert atmosphere. Oxygen may be present during dry distillation, but it is preferable to treat in an inert atmosphere because the combustion of carbonaceous matter can be controlled. Further, as described above, the co-carbonization phenomenon occurs when the combustible waste and the plastics are mixed in a specific ratio, so that the carbonization is preferably carried out in an inert atmosphere. Further, by performing carbonization in an inert atmosphere, it is possible to suppress the production of dioxins.

As the preliminary dry distillation furnace and the dry distillation furnace, general industrial furnaces can be used. For example, a rotary kiln, a fluidized bed furnace, a coke oven, a continuous carbonization furnace, a batch carbonization furnace, etc. can be used.

The preliminary carbonization temperature is 80 at 300 ° C. or higher, depending on the moldability after the preliminary carbonization and the properties of the activated carbon after the second carbonization.
It is preferable that the temperature is 0 ° C or lower, and particularly 70 at 400 ° C or higher.
The temperature is preferably 0 ° C or lower. If the temperature is lower than 300 ° C., unburned materials are volatilized in the second stage of the carbonization process, and the strength of activated carbon cannot be obtained. If the preliminary carbonization temperature exceeds 800 ° C., the specific surface area of the carbide after the preliminary carbonization becomes small depending on the type of combustible waste, so that the product properties as activated carbon deteriorate.

By providing the preliminary carbonization step, it becomes possible to manufacture a stable activated carbon product against variations in the garbage composition depending on the type of combustible waste and the season. In addition, the vinyl chloride resin contained in the plastics contained in the raw material is melted or decomposed by the operation of preliminary dry distillation temperature and time, and dehydrochlorination occurs. The dechlorinated resin is converted into char and carbonized by the dry distillation treatment in the next step. As described above, a part of the gasified resin or a part of the molten resin is recrystallized by the co-carbonization phenomenon, so that the amount of carbides after preliminary carbonization increases.

The preliminary carbide obtained by preliminary carbonization is
Although it can be used as granular activated carbon while maintaining the shape before pre-carbonization, the final product carbonized product is formed by crushing the pre-carbonized product by a simple crushing process and then using a general molding machine. May be used as As the molding machine, for example, a ring die compression molding machine, a flat die compression molding machine, a twin-screw extrusion molding machine, a briquette machine, or the like can be used.
In particular, briquetting is preferably performed using a briquette molding machine. Preliminary carbonization is easier to pulverize than the raw material before carbonization. Therefore, by providing the pulverization step after preliminary carbonization, the power required for pulverization is reduced. Further, by providing a molding step after crushing, it becomes possible to manufacture granular activated carbon suitable for the purpose even if the combustible waste is RDF or the like having various particle sizes. As a result, the restrictions on usage will be reduced,
It can be used in various fields for water treatment and gas treatment. Further, by atomizing the preliminary carbides in the pulverizing step, the dispersibility of the binder described later is improved in the molding step, so that the physical strength of the final granular activated carbon can be increased.

As described above, a binder and coal or coke may be added before forming the carbonized product after preliminary carbonization. By doing so, not only the cold strength after molding the preliminary carbide can be improved, but also the strength of the activated carbon after the second stage carbonization can be improved. In addition, it becomes possible to manufacture activated carbon whose properties are stable against variations in the composition of combustible wastes and seasonal changes in waste composition. Furthermore, the addition of the binder can reduce the ash content in the activated carbon, and consequently improve the adsorption performance of the activated carbon.

Specific examples of the binder include cement as an inorganic binder, and coal tar-based heavy oil, pitch, coal liquefied oil, and a petroleum-based reduced pressure residue from a specific oil system as an organic binder. Oil, ethylene bottom oil, reformed oil and the like can be mentioned. Any of these oils,
Alternatively, it may be a mixture. The addition amount varies depending on the target strength, but is preferably 5% by weight to 30% by weight, and particularly preferably 8% by weight to 25% by weight with respect to the preliminary carbide.
Even if the amount of binder added is the same, the dispersibility of the binder varies depending on the particle size of the preliminary carbide, so the amount of binder added varies depending on the particle size of the preliminary carbide.

As the coal, caking coal, slightly caking coal or strong caking coal is preferable, and among them, coal having high fluidity is particularly preferable. Further, it is preferable that the coal is pulverized into a predetermined particle size before being added.

The addition amount varies depending on the addition amount of the binder and the like, but is preferably 5% by weight to 30% by weight, and particularly preferably 8% by weight to 25% by weight with respect to the preliminary carbide.

As described above, the preliminarily carbide formed as required is subjected to the second stage of carbonization process to produce activated carbon.
As described above, activated carbon can be produced by omitting preliminary dry distillation and subjecting the raw material for dry distillation composed of combustible wastes and plastics only to the second dry distillation step.

The carbonization temperature of the second stage is 10 at 600 ° C or higher.
The temperature is preferably 00 ° C or lower, particularly preferably 700 ° C or higher and 900 ° C or lower. If it is less than 600 ° C, the performance as activated carbon cannot be obtained. On the other hand, when the temperature exceeds 1000 ° C., the performance improvement of the activated carbon reaches a saturated state, and not only the effect commensurate with the input heat amount cannot be obtained, but also the quality of the activated carbon may be deteriorated due to the melting of some ash components. The carbonization time depends on the carbonization temperature and the particle size of the raw material, but when the carbonization temperature is 700 ° C., it takes at least about 30 minutes, and when the carbonization temperature is 900 ° C., it requires at least about 20 minutes. The dry distillation time here means the effective residence time after the raw material inside the dry distillation furnace such as a kiln reaches the dry distillation temperature.

Incidentally, activation treatment with steam or the like may be carried out at the time of dry distillation. Specifically, the dry distillation treatment may be performed in the presence of steam. By the activation treatment, the specific surface area and pore volume of the carbide are increased, and the adsorption performance of activated carbon can be improved. However, it should be noted that when the ash content in the carbide is large, the physical strength may decrease due to the consumption of carbonaceous matter.

Further, flammable dry distillation gas generated during dry distillation may be used as a heat source for dry distillation. This is preferable because the dry distillation gas can be effectively used in the system of the dry distillation process. Further, since the amount of gas discharged from the carbonization process is small, the equipment for cleaning these gases can be downsized. Further, it is possible to supply the carbonization gas as an energy source for various adjacent processes.

[0039]

EXAMPLES Examples of the present invention will be described below.

Using the production method according to the present invention, activated carbon was produced from wood / paper and plastics by two-stage dry distillation. FIG. 1 shows a schematic diagram of the production flow of the activated carbon used in this example. Put the wood / paper waste pit 1 and the plastic waste pit 2 into the crusher 3 at a predetermined ratio, pass through the crusher 4, and then convey by the belt conveyor 5, on the way,
The magnetic material is removed by passing through the magnetic separator 6. Then, the non-magnetic metal and other heavy substances are removed through the wind power sorter 7, and then the granulator 10 is used to form a predetermined solid size through the separator 8 and the storage tank 9. The molded solid A is
Belt receiving conveyor 25 for receiving solids 1
1 where it can be stored in a predetermined amount.

The solid A thus obtained is fed to a preliminary carbonization furnace 12 comprising a rotary kiln. The obtained pre-carbide is pulverized by a pulverizer 13 to make fine particles, and the wind separator 14 again removes non-ferrous metal and metal, and then is conveyed to the weighing hopper 17 by the belt conveyor 26 through the sieve 15. After that, it is sent to the mixer 18 by the belt conveyor 27, where it is sufficiently mixed with the binder supplied from the binder supply tank 19. After the mixture is molded by the briquette molding machine 20, the powder material is removed by the sieve 21. The preliminary carbide having a large particle size selected by the sieve 15 is again sent to the pulverizer 13 to be atomized.

The obtained molded product B is dry-distilled in a dry-distillation furnace 22 composed of a rotary kiln. After the dry distillate is cooled to a predetermined temperature by the product cooler 23, the target activated carbon 28 is obtained. Dry distillation furnace 22, product cooler 23
The powdery material C generated inside is sent to the regenerated powder hopper 16,
Used as a raw material for molding.

Table 1 shows trees (including bamboo) used for preliminary carbonization.
・ Indicates the mixing ratio of paper / plastics, wood + corn / plastics, paper + coffee grounds / plastics.

[0044]

[Table 1]

Table 1 and FIG. 2 show an example of the result of measuring the carbonization yield during preliminary dry distillation. Preliminary carbonization temperature: 7
The results are obtained under the conditions of 00 ° C. and dry distillation time: 700 ° C. for 30 minutes. The carbonization yield is the ratio of the weight of the carbide obtained after carbonization to the weight of the raw material before carbonization.

As is clear from Table 1 and FIG. 2, in the case of a mixture in which the main raw material is paper, if the addition ratio of plastics is up to 30% by weight of the whole, the main raw material is wood (including bamboo). In the case of the mixture, the carbonization yield of the mixture as a whole does not decrease if the addition rate of plastics is up to 50% by weight, and not only papers / woods but also plastics are carbonized together (co-carbonization). I know what to do.

The dotted line shown as the additivity line indicates the carbonization yield of a mixture of papers and plastics, and wood and plastics when the papers, woods, and plastics are individually carbonized. It is obtained by totaling the yields of carbonization. However, only paper and wood are carbonized,
It says that plastics will not be carbonized at all. As the plastics do not carbonize, as the additivity lines indicate, the carbonization yield of each mixture decreases linearly towards 0% with increasing plastic loading. From the comparison between the additive line and the measurement result of the example, the effect of promoting the carbonization of the plastics in the present invention is clear.

Further, Table 1 and FIG. 3 show an example of the results of measuring the specific surface area of the preliminary carbide. Specific surface area is BET
It was measured by the method. As is clear from Table 1 and FIG. 3, when the main raw material is a mixture of papers, the plastic addition rate is up to 30% by weight, and when the main raw material is a mixture of woods, The total addition rate is 50
It can be seen that when the content is up to wt%, the specific surface area of each preliminary carbide is high, that is, it has a porous shape, and exhibits good properties suitable for activated carbon.

Further, as is clear from Table 1, the addition rate of plastics in the mixture of paper as the main raw material is 5 to 30.
It can be seen that in the case of wt%, the moldability before preliminary carbonization is good or very good. Further, it can be seen that the moldability before preliminary carbonization is very good when the addition rate of the plastics in the mixture of the main raw material is wood is 50% by weight or less.

In Table 2, dry distillation conditions, blending ratio, molding conditions,
And product properties are shown. Using the raw materials A to D of the mixed molding of wood / paper / plastics shown in Table 1, activated carbon was produced under the conditions shown in Table 2 according to the production flow shown in FIG. The strength was based on the pressure strength.

[0051]

[Table 2-1]

[0052]

[Table 2-2]

As is clear from the results shown in Table 2, the product properties of the obtained activated carbon are sufficiently high in both crushing strength and specific surface area.

Further, Table 3 shows, as a comparative example, dry distillation conditions, blending ratios, molding conditions and product properties of activated carbon manufactured under the conditions that do not satisfy the manufacturing conditions according to the present invention.

[0055]

[Table 3]

As is apparent from Table 3, at least one of crush strength and specific surface area, which are product properties, is insufficient. As described above, the effect of the present invention was confirmed.

[0057]

As described above in detail, carbonization of plastics is promoted by the co-carbonization of the present invention, and activated carbon can be produced in a high yield. At the same time, activated carbon with stable quality and excellent performance can be produced.
Further, the present invention is a recycling technology in which a part of plastics, most of which is gasified by heating, remains as fixed carbon and can be used as a functional material.

[Brief description of drawings]

FIG. 1 is a diagram showing a production flow of activated carbon used in Examples.

FIG. 2 is a diagram showing an example of a measurement result of carbonization yield during preliminary dry distillation in Examples.

FIG. 3 is a diagram showing an example of measurement results of specific surface areas of preliminary carbides in Examples.

[Explanation of symbols]

1 ... Wood and paper waste pit 2. Plastic waste pit 3 ... Crusher 4 ... Crusher 5, 25, 26, 27 ... Belt conveyor 6 ... Magnetic separator 7, 14 ... Wind power sorter 8 ... Separator 9 ... Storage tank 10 ... Granulator 11 ... Solid receiving hopper 12 ... Preliminary carbonization furnace 13 ... Crusher 15, 21 ... Sieve 16 ... Recycled powder hopper 17 ... Weighing hopper 18 ... mixer 19 ... Binder supply tank 20 ... Briquette molding machine 22 ... Dry distillation furnace 23 ... Product cooler 24 ... Cooling tower 28 ... Activated carbon A ... Solid B ... Molded product C ... powder

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) C08J 11/12 C10B 53/00 A C10B 53/00 B 53/02 53/02 57/02 57/02 B09B 3/00 ZAB (72) Inventor Toshihiko Okada 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Tatsuro Ariyama 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo In-house F-term (reference) 4D004 AA04 AA07 AA12 BA06 CA15 CA26 CC17 DA03 DA10 4F301 CA09 CA25 CA52 CA71 4G046 HA01 HA03 HA09 HC16 4H012 HA03 HB03 JA03

Claims (9)

[Claims] 1. A method for producing activated carbon, which comprises adding synthetic resins to an organic hydrocarbon compound and then carbonizing the mixture by carbonization. 2. A method for producing activated carbon, which comprises adding plastics to a combustible waste in a predetermined ratio and then carbonizing the mixture by dry distillation. 3. The method according to claim 2, wherein the combustible waste is solid waste. 4. Method according to claim 2 or 3, characterized in that the combustible waste is wood and / or paper. 5. The method according to claim 2, wherein the combustible waste is a food waste such as crushed corn core and coffee grounds. 6. The entire plastic is 5 to 50
3. The composition according to claim 2, wherein the amount is added so as to be in a weight%.
5. The method according to any one of 5 to 5. 7. The total amount of the plastics is 5 to 30.
3. The composition according to claim 2, wherein the amount is added so as to be in a weight%.
5. The method according to any one of 5 to 5. 8. The method according to claim 2, wherein the plastics are added to the combustible waste and then mixed before carbonization. 9. The method according to claim 2, wherein a two-stage dry distillation is carried out in the dry distillation step.