JPH05147913A - Production of activated carbon made of spherical fiber lump - Google Patents

Abstract

PURPOSE:To improve a binder to be used for producing activated carbon made of a spherical fiber lump by using tar pitch as a raw material. CONSTITUTION:Pitch fiber obtained by melt spinning is made infusible and the obtained infusible fiber is cut or crashed and sphered. In this stage, coal- based and/or petroleum-based fine powdery pitch especially the same having 5-20mum average particle diameter is used as a binder. This fine powdery pitch is mixed with the infusible fiber. Water is added to the mixture containing fine powdery pitch at 5-30wt.% and the obtained mixture is sphered. Thereby productivity is improved in comparison with a conventional method wherein a resin solution is used as the binder and with a method for using suspension in which fine powdery pitch is dispersed in water. Besides, activated carbon made of a spherical fiber lump having stable quality is produced industrially and favorably at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a spherical fiber lump activated carbon from tar pitch as a raw material, particularly a spherical fiber lump activated carbon used in the fields of separation, removal, purification, recovery, deodorization, deodorization, catalysts and the like. The present invention relates to a manufacturing method of.

[0002]

2. Description of the Related Art Activated carbon fibers have a high adsorption rate and a large specific surface area per unit weight, and are therefore used as filters and the like for gas phase adsorption and liquid phase adsorption. However, activated carbon fibers are disclosed in JP-A-61-132629 and JP-A-63.
As it is felt-like or mat-like as seen in -53294 publication, there are problems that it is bulky relative to its weight, is difficult to handle, and increases pressure loss when it is packed in an adsorption tower, etc. .. Therefore, conventionally, a method of molding a felt-like activated carbon fiber with a resin, a method of molding with a papermaking method, a method of adsorbing a desired substance into a spherical shape having a diameter of 10 to 20 mm by solidifying the activated carbon fiber with a resin, etc. have been adopted. There is. Furthermore, in order to solve the above-mentioned problems, Japanese Patent Application Laid-Open No. Hei 2
-38374 publication, a method of obtaining a block of infusible pitch-based fibers and a liquid containing a carbon-containing resin, and extruding and granulating the mixture to obtain a lump, and activating this to obtain an activated carbon fiber lump. However, the method of spheroidizing is not specified.

Explaining the case of the lump described in the above-mentioned Japanese Patent Laid-Open No. 2-38374, the manufacturing process becomes complicated, and the carbon fiber is compressed and cut or divided to obtain the lump. Therefore, the relatively fragile raw material fiber is pulverized or shortened. Also, phenolic resin, which is a carbon material used as a binder,
Epoxy resin and the like are expensive, and their cost impact is not small. The present inventors have previously subjected the granulated material obtained by crushing granulation or extrusion granulation of the pitch fiber in a medium containing a binder to rolling treatment, and then subjecting it to drying, infusibilization, carbonization, and activation treatment. A spherical fiber lump activated carbon obtained as described above and a method for producing the same were provided (Japanese Patent Application No. 2-129247). This spherical fibrous lump activated carbon has the advantages of high adsorption capacity, fast adsorption / desorption rate, excellent handleability and shape retention, and extremely low fluid passage resistance, but this manufacturing method also has complicated steps and There is room left.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a method capable of producing a spherical fiber lump activated carbon having a high strength in a simple process.

[0005]

In the present invention, it has been found that the above problems can be solved by mixing a plurality of activated carbon fibers with a pitch binder and then adding water to make the particles spherical. That is, the present invention prepares a pitch for spinning using tar pitch as a raw material, melt-spins the pitch into pitch fibers, infusibilizes the same in an oxidizing atmosphere, and then binds a plurality of the infusible fibers with a binder. Spheroidized in the presence of, to produce a spherical fiber lump activated carbon by activating the generated spherical carbon fiber, using fine pitch powder as the binder during spheroidization, the fine pitch powder in the infusible fiber Mix the powders,
Provided is a method for producing a spherical fiber lump activated carbon, which comprises adding water to the produced mixture to effect spheroidization.

In the method of the present invention, pitch fibers are infusibilized in an oxidizing atmosphere, and then coal-based and / or petroleum-based fine pitch powders are added as a binder to a plurality of infusible fibers and mixed. The pitch fine powder in a dry state here means pitch fine powder without water.
Next, while adding water to this mixture, for example, it is spheroidized by a tumbling granulator, and the generated spheres are dried and cured, and then activated. Pitch average particle size 5-20μ
The fine powder is pulverized into m, and the fine powder is mixed in a dry state with the infusible fiber as a raw material, and the pitch fine powder is contained in the resulting mixture in an amount of 5 to 30 wt%, preferably 10 to 25 wt%. Then, this mixture is fed to a tumbling type granulator by a quantitative feeder to obtain spherical fiber lumps having a diameter of 1 to 10 mm while adding water. If the average particle size of the pitch fine powder used as a binder is less than 5 μm, the manufacturing cost of the binder will be high, and if it exceeds 20 μm, the binding effect as a binder will be weak. If the pitch fine powder is less than 5 wt%, the effect as a binder is weak, and if it exceeds 30 wt%, the strength is improved. The properties of the fiber deteriorate. The amount of water added is preferably 30 to 60 parts by weight with respect to 100 parts by weight of the infusible fiber. If it is less than 30 parts by weight or more than 60 parts by weight, spheroidization becomes difficult.

The produced spherical fiber lumps may be treated with a ball sphering machine as required to increase the sphericity and the density. Then, the spherical carbon fiber mass was
It is heated at a temperature of 0 to 200 ° C. for 60 to 120 minutes and then cooled to be cured, and then activated by a known method such as chemical activation, gas activation, and water vapor activation. As the pitch fine powder used for the binder, it is possible to use ordinary coal-based pitch and petroleum-based pitch that have a softening point of 110 ° C. or less and are easily available.

In the method of the present invention, since fine pitch powder is used as a fiber binder when the infusible fiber is spheroidized, the pitch for binder is melted in the drying process after the spheroidizing treatment, so that the individual fibers are melted. In addition to facilitating handling in the post-drying step because it increases the binding force between the two, since many pores are also formed on the surface of the carbonized material produced by the binder carbonization in the activation step The specific surface area of the whole assembly increases. Further, since the pitch for binder is made of general-purpose pitch as a raw material, it is inexpensive and the manufacturing cost of the spherical fiber lump activated carbon can be reduced.

Further, in the method of the present invention, since water is added to the mixture of the pitch fine powder for binder and the infusible fiber, when a suspension of the fine pitch powder in water is used. It was found that the fine pitch powder in the piping system, which tends to occur easily, can be prevented from settling and clogging, and that the spherical carbon fiber particles obtained after spheroidizing and drying and hardening have an excellent crushing load. The reason why the crushing load of the obtained spherical carbon fiber particles is superior to the case where the pitch fine powder suspension is used is that the pitch as a binder is uniformly distributed in the obtained spherical carbon fiber particles. Can be considered. The pitch fine powder for binder is preferably fine, and is preferably about 1/5 to 5/5 of the diameter of the raw material carbon fiber. Finer particles will increase the manufacturing cost of the binder, and coarser particles will weaken the binding effect as a binder, and will reduce the strength of the spherical fibrous activated carbon particles.

Next, the present invention will be described with reference to Examples and Comparative Examples. Example 1 Highly refined coal tar pitch having a softening point of 230 ° C. is melt-spun to obtain pitch fiber, which is 300 ° C. in air.
Infusible, and then cut to an average length of 0.6 mm by a guillotine-type automatic fiber cutting machine, and a fine pitch powder with an average particle size of 5 μm (softening point: 94 ° C. coal pitch, Kawasaki Steel Co.
PK-E), and then crushed by a rotary disk type coffee mill grinder. A mixture obtained by mixing fine pitch powder in a dry state with the produced fiber was spheroidized while adding water to a small dish granulator with a diameter of 300 mm to form a spherical fiber mass with an average particle diameter of 3.1 mm. Obtained. After the spherical fiber mass was dried and cured at 150 ° C. for 2 hours, the crushing load of the spherical carbon fiber particles was measured.

Table 1 shows the conditions for the spheroidizing treatment and the obtained crushing load, and Table 2 shows the treating conditions for the dish type granulator used for the spheroidizing treatment. The crush load was measured by an autograph (DCS-500 manufactured by Shimadzu Corporation).
In the formula for calculating the binder addition rate (weight ratio) in Table 1, the binder residual carbon content is the weight of residual carbon when the pitch fine powder used as the binder is heated from room temperature to 800 ° C in an inert atmosphere. Is.

Table 1: Spheroidizing treatment performed by mixing pitch fine powder binder in a dry state with infusible fiber and adding water to the mixture (average particle size of pitch fine powder 5 μm)

[Table 1]

Table 2: Spheroidizing conditions in the dish granulator

[Table 2]

Finally, the average particle size obtained as described above 3.
200 mm long, 200 mm wide, 200 mm high with 1 mm spherical fiber mass
It was filled up to a height of 100 mm in a box-shaped furnace of, and activated for 2.5 hours at 900 ° C in a 33% steam atmosphere.
A spherical fiber lump activated carbon having a specific surface area of 1500 m ² / g was obtained. In addition,
Specific surface area is measured by Shimadzu Corporation, Asap 2400
(Trade name) was used.

Comparative Example 1 The same as Example 1 except that a suspension of pitch fine powder in water was used instead of mixing pitch fine powder as a binder in a dry state with infusible fibers. As a result, a spherical carbon fiber mass having an average particle diameter of 3.1 mm was obtained, which was then dried and cured, and then the crush load was measured. The processing conditions in the dish granulator are the same as those shown in Table 2. Table 3 shows the conditions of the spheroidizing treatment and the crushing load of the obtained spherical carbon fiber particles. In the formula for calculating the binder addition rate (weight ratio) in Table 3, the binder residual carbon content is the weight of residual carbon when the binder suspension used is heated to 800 ° C. in an inert atmosphere. From the values of the crushing load of the spherical carbon fiber particles shown in Table 1 and Table 3, the crushing load when the pitch fine powder binder was added as a suspension in which water was dispersed was infusibilized in the dry state. It can be seen that it is only about 70% when mixed with fiber.

Table 3: Spheronization treatment performed by adding pitch fine powder binder in the form of a suspension in which water is dispersed.

[Table 3]

Comparative Example 2 A spherical carbon fiber having an average particle diameter of 3.1 mm was obtained in the same manner as in Example 1 except that pitch fine powder having an average particle diameter of 30 μm was used as a binder, and its crush load was measured. The processing conditions in the dish granulator are the same as those shown in Table 2. Table 4 shows the conditions of the spheroidizing treatment and the crushing load of the obtained spherical carbon fiber particles.

From the values of the crushing load of the spherical carbon fiber particles shown in Tables 1 and 4, the crushing load when the pitch fine powder having an average particle size of 30 μm is used is the case when the pitch fine powder having an average particle size of 5 μm is used. It turns out that it is only about 80% of.

Table 4: Spheroidizing treatment performed by mixing pitch fine powder binder in a dry state with infusibilized fiber and adding water to this mixture (average particle diameter of pitch fine powder 30 μm)

[Table 4]

[0020]

As described above, in the method of the present invention,
In producing spherical fiber lump activated carbon, inexpensive coal-based and / or petroleum-based pitch is used as a binder in a finely powdered form, and the infusible carbon fiber as a raw material is mixed with the pitch fine powder in a dry state, Compared with the conventional method of using a resin such as a phenolic or epoxy resin as a binder by adding water to this mixture to make it spherical, or adding it as a suspension in which pitch fine powder is dispersed in water. Therefore, productivity can be improved, and industrially advantageous,
Moreover, it is possible to inexpensively produce spherical fiber lump activated carbon,
The ripple effect on industry is very large.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Hanatani 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Technical Research Division (72) Masayuki Kakuno 1 Kawasaki-cho, Chiba-chi, Kawasaki Steel Co., Ltd. Research headquarters

Claims (3)

[Claims] 1. A pitch for spinning is prepared from tar pitch as a raw material, and the pitch is melt-spun to form a pitch fiber,
This is infusibilized in an oxidizing atmosphere, then a plurality of the infusibilized fibers are aggregated in the presence of a binder to be spheroidized, and the generated spherical carbon fibers are activated to produce a spherical fiber lump activated carbon. At the time of spheroidizing, the pitch fine powder is used as the binder at the time of spheroidizing, the pitch fine powder is mixed with the infusible fiber, and water is added to the resulting mixture to perform spheroidizing. Method for producing lump activated carbon. 2. The method according to claim 1, wherein the fine pitch powder used as the binder has an average particle size of 5 to 20 μm. 3. Mixing the infusible fiber and the pitch fine powder so that the pitch fine powder used as the binder occupies 5 to 30 wt% of the mixture of the infusible fiber and the pitch fine powder. The method according to claim 1, characterized in that