JPS5910931B2 - Method for manufacturing spherical carbon molded bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spherical carbon molded body having high strength and an activated spherical carbon molded body.

Specifically, 5 to 50 parts by weight of a mixture consisting of 30 to 95% by weight of petroleum-based or coal-based pitch and 5 to 70% by weight of amorphous carbon particles with a diameter of 200 μ or less and 5 to 50 parts by weight of boiling point 200
A viscosity modifier selected from 2- to 3-ring aromatic compounds or mixtures thereof having a temperature of 2- to 3-ring aromatic compounds or mixtures thereof is melt-mixed, and then the mixture is heated in hot water at a temperature ranging from the softening point to 30 °C higher than the softening point. After spheroidizing the pitch mixture, extracting the viscosity modifier in the resulting pitch mixture spherules with a solvent, and making the resulting porous pitch mixture spherules non-spheroidal, the resulting infusible pitch mixture spherules are fired. A method for producing a spherical carbon molded body, characterized by a method for producing a spherical carbon molded body, and an activated spherical carbon molded body, characterized by activating the above-mentioned infusible pitch mixture spherical molded body or spherical carbon molded body with an activator mainly composed of nitrogen and water vapor. The present invention relates to a method for manufacturing a body (hereinafter abbreviated as a spherical activated carbon molded body).

Conventionally, methods for producing spherical carbon molded bodies or spherical activated carbon molded bodies include a method of mixing powdered charcoal with a caking agent and molding the mixture;
Alternatively, a viscosity modifier is mixed with petroleum-based or coal-based pitch with specific properties, and after melt molding, the viscosity modifier is extracted with a solvent.
Subsequently, methods of infusibility, firing, or infusibility and activation have been carried out.

In particular, according to the latter method, it is possible to obtain a special spherical carbon molded body with a small apparent specific gravity that is difficult to pulverize and can be used as various carbon materials. The method is considered advantageous because it can be effectively used for treatment and smoke exhaust treatment.

However, a carbon molded article and an activated carbon molded article with high strength cannot be obtained by the above method.

When using a carbon molded body, particularly crushing strength and abrasion strength are sometimes required.

For example, when performing wastewater treatment using fixed bed or fluidized bed methods,
If the crushing strength or abrasion strength of the activated carbon is low, it will break at the lower part, or it will become powdered due to the friction caused by the flow, causing clogging, etc., and reducing efficiency.

If these strengths are high, the height of the activated carbon bed layer can be increased, and the flow rate can also be controlled, making it possible to treat wastewater extremely efficiently.

In addition, high-strength carbon molded bodies are used in a wide range of fields, and such carbon molded bodies are strongly desired.

An object of the present invention is to provide a spherical carbon molded body having high crushing strength and abrasion strength that meets the above-mentioned demands, as well as a novel method for producing a spherical activated carbon molded body.

The present invention will be explained in detail below. The present invention involves mixing 5 to 50 parts by weight of a viscosity modifier to 100 parts by weight of a mixture consisting of 30 to 95% by weight of petroleum-based or coal-based pitch and 5 to 70% by weight of amorphous carbon particles with a diameter of 200 μ or less, After melt molding, the viscosity modifier is extracted with a solvent and made infusible, fired, or made infusible and activated by a conventional method.

Examples of the petroleum-based pitch used in the present invention include thermally decomposed pitches of petroleum products (crude oil, heavy oil, naphtha, asphalt, light oil, kerosene, etc.) and pitches obtained by heating these to make them heavier.

The coal-based pitch is preferably a heavy pitch such as high pitch or medium pitch, and the pitch used preferably has a softening point of 140°C or higher.

The amorphous carbon used in the present invention is charcoal obtained by carbonizing wood, palm, sawdust, etc., such as coconut charcoal, base ash, etc., or a carbonized product of coal. Fine powder particles, which are mainly composed of so-called amorphous carbon such as certain green coke and carbon black, and have a particle size of 200 μm or less are used.

The ratio of pitch to amorphous carbon particles is 30 to 95.
The content of amorphous carbon is 5 to 70% by weight, and preferably 5 to 50% by weight of amorphous carbon.

If the amount of amorphous carbon is less than 5% by weight, no strength imparting effect is observed, and if the amount of amorphous carbon is more than 70% by weight, the viscosity of the pitch mixture becomes too high, making it difficult to mold and spheroidize it.

The amorphous carbon particles preferably have a particle size of 200 μm or less, preferably 150 μm or less, and if the size is larger than 200 μm, when forming fine spherical charcoal, unevenness will occur due to the amorphous carbon particles, making it difficult to form into a preferred spherical shape. This becomes difficult.

The viscosity modifier used in the present invention has good compatibility with pitch and is a 2- to 3-ring aromatic compound with a boiling point of 200° C. or higher, such as naphthalene, methylnaphculene, phenylnaphthalene, benzinenaphthalene, It is selected from one or a mixture of two or more of methylanthracene, phenanthrene, biphenyl, and the like.

Among these, naflerene is particularly preferred from the viewpoint of its remarkable viscosity regulating effect and easy extraction in the solvent extraction step.

The amount of viscosity modifier used is 10% of the mixture of pitch and amorphous carbon.
Although 5 to 50 parts by weight is used relative to 0 parts by weight, the amount of the viscosity modifier varies depending on the mixing ratio of pitch and amorphous carbon.

When the ratio of amorphous carbon becomes high, the viscosity of the mixture becomes high, so it is preferable to use a high amount of viscosity modifier, and when the ratio of amorphous carbon is small, the amount of viscosity modifier can be reduced.

However, if the amount of the viscosity modifier is less than 5 parts by weight per 100 parts by weight of the mixture of pitch and amorphous carbon particles, will the viscosity be high? If the temperature is too high, molding becomes difficult, and the resulting molded product becomes non-porous, making it difficult to make it infusible.

On the other hand, when the amount of the viscosity modifier is more than 50 parts by weight, the molded product obtained after extraction becomes too macroporous.
It becomes brittle and its strength deteriorates.

The following method is used for melt molding the mixture of pitch, amorphous carbon particles, and viscosity modifier.

For example, in order to obtain spherical charcoal, the above-mentioned mixture may be melted and then poured into water in which a surfactant has been dissolved and stirred under pressure to form micro-spheres. A method of melting and extruding it into a string shape, cooling and crushing it to form pellets or small rods, and then spheroidizing this by pouring it into water in which a surfactant with a temperature higher than the softening point of the pitch mixture is dissolved can be used. .

If the amount of amorphous carbon is small, the former method of spherical molding can be used, but since the amount of amorphous carbon becomes large, the viscosity becomes large, making the former method difficult, so the latter method is not recommended. preferable.

In either case, the temperature of the hot water in which the surfactant was dissolved was kept from the softening point to a temperature 30°C higher than the softening point to prevent the amorphous carbon particles in the pitch mixture from separating during spheronization. It is necessary to.

Generally temperatures of 50°C to 80°C are used.

The pitch spherical bodies obtained in this way are, for example,
The viscosity modifier is extracted and removed with an organic solvent by a known method disclosed in Japanese Patent Publication No. 0-18879 and Japanese Patent Publication No. 51-76. An activated carbon molded body can be obtained.

Organic solvents used here include aliphatic hydrocarbons such as hexane, heptane, naphtha, kerosene, etc., which have low solubility for pitch and amorphous carbon, and high solubility for the viscosity modifier used. Examples include alicyclic hydrocarbons and aliphatic alcohols such as methanol, ethanol, and propanol.

Note that the extraction of the viscosity modifier using the organic solvent may be performed in a single stage or in a multistage manner.

The porous pitch mixture spherical molded body thus obtained is oxidized with an oxidizing agent at a temperature of up to 400'C to obtain a porous, infusible pitch mixture spherical molded body that is heat-infusible.

The oxidizing agent used for this infusibility treatment is 02,03,SO
Examples include NO.3, NO, a mixed gas of these diluted with air or nitrogen, and an oxidizing gas such as air.

The infusible pitch mixture spherical molded body is then fired in an inert atmosphere at a temperature of 600° C. or higher to obtain a spherical carbon molded body.

Moreover, a spherical activated carbon molded body can be easily obtained by activating the above-mentioned infusible pitch mixture-like molded body or spherical carbon molded body with an activator mainly composed of nitrogen and water vapor.

The spherical carbon molded body or the spherical activated carbon molded body obtained by the method of the present invention becomes a spherical carbon molded body produced from pitch without mixing amorphous carbon, and the crushing strength is greatly improved, about 1.5 Up to 3 times more.

Moreover, its abrasion strength is also greatly improved. Moreover, since other properties such as adsorption capacity hardly change, this method can be said to be an innovative method for producing carbon molded bodies or activated carbon molded bodies.

Furthermore, since the amorphous carbon used in the present invention is inexpensive, it is economically advantageous especially in the production of activated carbon molded bodies with low activation yields.

Furthermore, when producing spherical coal from pitch using the conventional method,
It has been difficult to produce excellent spherical coal without using pitch of a certain quality or higher, but the method of the present invention expands the range of softening temperatures and types of pitch that can be used, and it There is an advantage that excellent spherical carbon molded bodies can be obtained even when using carbon-based or coal-based pitch.

Examples will be illustrated below.

Example 1 Pitch 50k9 obtained by naphtha thermal decomposition with a softening point of 182°C, quinoline insoluble content of 10%, and physical properties of H/C of 0.53 and coconut charcoal 2 with a particle size of 150μ or less
A mixture of 5k9 and naphthalene 25ky was charged into a pressure-resistant container with an internal volume of 300 liters equipped with a stirring blade, heated to melt at 210°C, and mixed.

The resulting mixture had a softening point of 68°C and a pour point of 75°C (the softening point and pour point were measured using a Koka type flow tester).

80-85 in a pressure container without taking out the mixture.
50 kg/cr? from a cap with 100 holes with a diameter of 1.5 mm provided at the bottom of the pressure vessel The pitch mixture was extruded under a pressure of L at a speed of 5 ky/m.

The extruded string-like material is placed along a gutter with an inclination of about 40 degrees.
It was made to flow down into the cooling tank of 5-20 degreeC.

At this time, the flow rate in the gutter is 2. The string-like material immediately after extrusion was continuously stretched by flowing water at a rate of 5 m/sec.

The string-like material thus obtained has a diameter of approximately 0. ! It was stretched to 5 mm and deposited in a cooling bath.

If this string autumn item is left to cool, it will harden and become so brittle that it can be easily broken by hand.

Cut this string-like material with water using a high-speed cutter (container: diameter 300
mmX height 5001nrIL; blade: length 100mmX
300 Or. p. m
．． The string-like material was completely crushed into small rod-like materials by stirring for 1 minute.

When this rod-shaped object was observed under a microscope, the ratio of the rod length to diameter was approximately 1.5.

Separate 200 g of this rod-shaped pitch from water, add it to 1 kg of a 0.5% aqueous solution of polyvinyl alcohol (saponification degree 88%), heat it to 80°C above the softening point, stir and disperse it, and the rod-shaped material will become spherical. Ta.

The beads are cooled to form spherical beads, the naphthalene in the beads is extracted with n-hexane, and the beads are dried with ventilation.

Next, oxidative infusibility was performed in a fluidized bed using air.

Infusibility conditions are 20 l/m for 100 g of beads.
Iyr of air is sent to 300℃ at a rate of 30℃/hr.
It became infusible by increasing the temperature.

Next, the infusible beads were heated at 200°C/h using a fluidized bed in a steam atmosphere containing an equal amount of N2 gas. The temperature was raised to 900°C at r and held at this temperature for 1 hour.

The obtained activated spherical carbon has a spherical shape with an average diameter of 650μ,
Apparent specific gravity 0.58 Iodine adsorption amount 11007729/g (equilibrium concentration 1 3
Value on 9/13) Caramel decolorization rate according to JIS K-1470 is 85%, hardness test according to JIS K-1474 is 98%, and crushing strength with average particle size of 650μ is 1
It was 1200g per grain.

Crushing strength (El/grain) is JIS standard sieve opening 590μ
One grain is selected from the sample between the top of the sieve and the bottom of the 710 μm sieve, and its crushing strength is measured using a hardness meter.

This test was conducted on 20 or more samples, and the average value is shown excluding the maximum and minimum values.

The hardness test expresses the frictional strength, and the
This indicates the rate at which the original shape is maintained without turning into powder due to friction.

Comparative Example 1 A mixture of 75 kg of naphtha pyrolyzed pitch and 25 kg of naphcrene was produced under substantially the same conditions as in Example 1 to obtain spherical pitch.

Next, infusibility and activation treatments were performed under the same conditions as in Example 1 to obtain spherical activated carbon.

The activated carbon had a spherical shape with an average diameter of 600μ, an apparent specific gravity of 0.60, an iodine adsorption amount of 1050 m9/g, and a caramel decolorization rate of 83%, and the adsorption capacity was almost the same as in Example 1. The hardness test of K-1474 was 85%, and the crushing strength per grain was 500g, indicating that the activated spherical carbon obtained in Example 1 was superior in crushing strength and friction strength. did.

Examples 2 to 4 Pitch obtained by pyrolysis of naphtha, coconut charcoal (particle size 150μ or less), and naphthalene were mixed in the proportions shown in Table 1, and the mixing proportions are expressed by weight.1 These mixtures were carried out. Melt molding, infusibility, and activation were carried out in the same manner as in Example 1.

Table 1 shows the properties of the obtained spherical activated carbon.

Example 5 The infusible beads obtained from the pitch composition of Example 1 were heated to 1000°C at 200°C/hr in a nitrogen atmosphere and held at this temperature for 1 hour to obtain a spherical carbon molded body. .

The average particle size of this product was 650 μm, and the apparent specific gravity was 0.61, and the crushing strength was 2000 g/1 particle.

On the other hand, when the infusible beads obtained from the pitch and naphculene mixture containing no coconut charcoal in Comparative Example 1 were treated in the same manner as described above, the average particle diameter was 600 μm, the apparent specific gravity was 070, and the crushing strength was 800 g/1 particle. there were.

Examples 6-10 Softening point 171° C1 Quinoline insoluble content 22.9%, I{/
30 parts by weight of various amorphous carbons shown in Table 2 and 40 parts by weight of naphthalene are mixed with 70 parts by weight of coal tar pitch having a physical property value of C0.61.

A spherical carbon molded body and a spherical activated carbon molded body were produced from this pitch composition in the same manner as in Example 1, and their properties are shown in Table 2.

Table 2 shows the properties of a spherical carbon molded body and a spherical activated carbon molded body made of only 100 parts by weight of coal tar pitch and 40 parts by weight of naphthalene as Comparative Example 2.

Example 11 Pitch obtained by thermal decomposition of asphalt (softening point 182° C1 quinoline insoluble content 169%, H/C = 0.8
2) 4. A mixture of 5 kg of coconut charcoal, 5 kg of coconut charcoal with a particle size of 150 μm or less, and 25 kg of naphcrene was placed in a pressure-resistant container with a capacity of 300 liters equipped with a stirring blade.
The mixture was heated and melted and mixed at °C.

The softening point of the resulting pitch mixture was 58°C.

Next, polyvinyl alcohol (02 with a degree of saponification of 88%)
% aqueous solution was added thereto, stirred at 71° C. and 300 rpm for 40 minutes to disperse, and then cooled to obtain a slurry of a spherical pitch composition.

After removing water by filtration, about 6 times the amount of normal hexane as compared to the pitch composition was added to extract and remove naphthalene.

This spherical pitch was subjected to infusibility and activation treatment in the same manner as in Example 1.

The apparent specific gravity of the obtained spherical activated carbon was 0.55, the iodine adsorption amount was 1200/9, the caramel decolorization rate was 82%, and the crushing strength was 9.
0 0 g/1 grain, and the hardness test result was 92%.

Example 12 The spherical carbon molded body obtained in Example 5 was activated under the same activation conditions as in Example 1 using a fluidized bed.

The obtained activated spherical carbon was spherical with an average diameter of 630μ,
The apparent specific gravity was 0.58, the iodine adsorption amount was 1100~/El, the caramel decolorization rate was 85%, the hardness test was 98%, and the crushing strength was 1200 g per particle with an average particle size of 650 μm.

It was found that the activated spherical carbon obtained in this example exhibited performance equivalent to that of the activated spherical carbon obtained in Example 1.

Claims (1)

[Claims] 1. Petroleum-based or coal-based pitch 30-95% by weight and diameter 20
Add 5 to 50 parts by weight of a viscosity modifier selected from 2- to 3-ring aromatic compounds or mixtures thereof with a boiling point of 200° C. or higher to 100 parts by weight of a mixture consisting of 5 to 70% by weight of amorphous carbon particles of 0μ or less. The mixture is then spheroidized in hot water ranging from the softening point to a temperature 30°C higher than the softening point, and the viscosity modifier in the resulting pitch mixture spherules is extracted with a solvent to form a porous mixture. 1. A method for producing a spherical carbon molded body, which comprises infusible pitch mixture spherical bodies and then firing the obtained infusible pitch mixture spherical molded body. 2. The method for producing a carbon molded body according to claim 1, wherein the amorphous carbon particles are selected from charcoal, green coke, and carbon black. 3 Petroleum-based or coal-based pitch 30-95% by weight and diameter 20
A viscosity modifier selected from 5 to 50 parts by weight of a 2- to 3-ring aromatic compound with a boiling point of 200°C or higher or a mixture thereof in 100 parts by weight of a mixture consisting of 5 to 70% by weight of amorphous carbon particles of 0μ or less. The mixture is then spheroidized in hot water ranging from the softening point to a temperature 30°C higher than the softening point, and the viscosity modifier in the resulting pitch mixture spherules is extracted with a solvent. An activated spherical carbon molded body characterized by infusibleizing a porous pitch mixture spherical body and then activating the obtained non-spacified pitch mixture spherical molded body with an activator mainly composed of nitrogen and water vapor. Production method. 4 Petroleum-based or coal-based pitch 30-95% by weight and diameter 20
Add 5 to 50 parts by weight of a viscosity modifier selected from 2- to 3-ring aromatic compounds or mixtures thereof with a boiling point of 200° C. or higher to 100 parts by weight of a mixture consisting of 5 to 70% by weight of amorphous carbon particles of 0μ or less. The mixture is then spheroidized in hot water ranging from the softening point to a temperature 30°C higher than the softening point, and the viscosity modifier in the resulting pitch mixture spherules is extracted with a solvent to form a porous mixture. A method for producing an activated spherical carbon molded body, which comprises making a spherical pitch mixture spherical body inert and firing, and then activating the obtained spherical carbon molded body with an activator mainly composed of nitrogen and water vapor. .