JPH08224468A - Cylindrically pelletized carbon based adsorbent - Google Patents

Abstract

PURPOSE: To provide a carbon based adsorbing excellent in adsorbing performance by making a pellet cylindrical and forming a hollow in the center part to increase the outer surface area of a particle per unit volume packing bed and shortening diffusing distance from the outside to the inside. CONSTITUTION: In the cylindrical pellet shaped carbon based adsorbent, cylindrical pallets having outside diameter (d1 ) of 1.0-10mm, inside diameter of 0.1d1 -0.5d1 and length of 2.0-15mm account for >=80% the total pellets the volume of fine pore having fine pore diameter of 0.01-10μm is 0.10-1.0cc/g, the volume of fine pore having pore diameter of <=100Å fine is 0.20-1.2cc/g, the bulk density of particle is 0.4-1.2g/cc and carbon content is >=90wt.%. The cylindrical adsorbent has large outer surface area, the mass transfer of fluid from the outer periphery to the inside is cased and excellent adsorbing performance is secured.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to separation and concentration of specific components in a gas phase or a liquid phase, for example, removal of odorous components, nitrogen oxides and sulfur oxides in the air, purification of waste liquids, waste water and tap water. It is intended for carbon-based granular adsorbents used for treatment, etc., and has a cylindrical shape to increase the outer surface area of adsorbent particles per unit packed bed volume, and the adsorbed substance is the outer surface of the particles. To reduce the diffusion distance from the
The present invention relates to a cylindrical pellet-shaped carbon-based adsorbent having improved adsorption performance.

[0002]

2. Description of the Related Art In recent years, the prevention of pollution and the protection of the global environment have been attracting worldwide attention. The removal of COD, heavy metals, and phosphorus in wastewater, as well as sulfur oxides, nitrogen oxides, and dioxins in exhaust gas. Various adsorbents have been effectively used to solve problems such as removal of mercury, recovery of CFCs, organic chlorine gas, and carbon dioxide.

Conventionally, as these adsorbents, inorganic adsorbents such as natural zeolite, synthetic zeolite, acid clay, silica gel, porous glass, etc., or carbonaceous adsorbents obtained from coconut shell charcoal, coal, charcoal, etc. Agents are widely used. Among them, a carbon-based adsorbent has a vast internal surface area obtained by carbonizing and activating a carbon substance or a substance containing carbon, and is an adsorbent having an excellent adsorption ability,
It is used in a wide range of fields today. For example, tobacco filters, refrigerator deodorants, household water purifiers, etc. in familiar places, liquid phase decolorization and purification of foods, pharmaceuticals, industrial chemicals, etc. in industrial applications, and process gas of various industries such as petrochemical industry. Its applications are diverse, including separation, purification, and recovery, as well as adsorption and removal of atmospheric sulfur oxides and nitrogen oxides, and prevention of water pollution. These carbon-based adsorbents are usually tried to be used in various forms such as granular, powdery, honeycomb, or fibrous, depending on the application. There are restrictions such as large loss, and the honeycomb type has a limited number of places to be mounted. The fibrous type has a high adsorption rate, but the packing density cannot be increased. Under the present circumstances, the granular adsorbent, which is easy to handle, is widely used due to the above limitation.

By the way, when the shapes of the granular adsorbents currently used are further classified, they are either crushed, columnar pellets, or spherical, and are compared with powdery and fibrous adsorbents. Since the outer surface area of the adsorbent particles per unit packed bed volume is small and the distance from the outer surface to the inner adsorption site is long, it takes a long time to adsorb and desorb the substance to be adsorbed, and an effective adsorption operation cannot be performed. There is a problem.

Further, as a carbon-based molding, Japanese Patent Publication No. 62-3
No. 0210, Japanese Patent Publication No. 62-30212, Japanese Patent Publication No. 62-30211, Japanese Patent Publication No. 62-30213, the thermosetting granular or powdery phenolic resin whose production method is disclosed. When used as a binder, a molded product having excellent strength can be obtained, which is disclosed in JP-B-60-59167 and JP-B-61-3.
It is disclosed in Japanese Patent No. 2247 and the like. However, in these molding methods, at present, a technique for sufficiently controlling characteristics such as porosity, specific surface area, and pore size distribution required as an adsorbent has not been established. Further, in these molding methods, the influence of the shape of the molded body on the adsorbent characteristics has not been examined. With respect to other carbon-based granular adsorbents, no detailed study has been made so far on optimization of pellet shape.

[0006]

The object of the present invention is to increase the outer surface area of adsorbent particles per unit packed bed volume by making the pellet shape cylindrical and forming a void in the center of the adsorbent. Another object of the present invention is to provide a carbon-based adsorbent having improved adsorption performance by shortening the diffusion distance of the substance to be adsorbed from the outer surface of the adsorbent to the internal adsorption site.

[0007]

The inventors of the present invention have completed the present invention as a result of earnest research to solve the above-mentioned problems, and its characteristic is that the outer diameter d ₁ is 1.0 ~
Cylindrical pellets with a diameter of 10 mm, an inner diameter d ₂ of 0.1 d _{1 to} 0.5 d ₁ and a length of 2.0 to 15 mm account for 80% or more of the whole, and the pore diameter.
Pore volume in the range of 0.01 to 10 μm is 0.10 to 1.0 cc / g, pore volume in the range of 100 Å or less is 0.20 to 1.2 cc / g, and particle bulk density is in the range of 0.40 to 1.2 g / cc. Yes, the carbon content is
It is to produce a carbonaceous adsorbent in the form of a cylindrical pellet in the range of 90% by weight or more.

The present inventors have made various studies on the blending amount of the binder, the use amount of the surfactant, and the specifications of the granulation equipment for molding, such as the shape of the die nozzle and the aperture ratio of the die nozzle. By doing so, it is possible to manufacture the cylindrical pellet-shaped carbonaceous adsorbent of the present invention.

The carbon material forming the carbon-based adsorbent according to the present invention is mainly composed of a plant-based porous carbon material such as charcoal, bamboo charcoal, and coconut palm charcoal, brown coal, bituminous coal, etc. It is possible to use a coal-based carbon material or a carbon material obtained by carbonizing a synthetic polymer material such as a thermosetting resin such as a phenol resin, a melamine resin, or a modified product thereof. These plant-based, coal-based, resin-based carbon materials,
In order to facilitate the molding, it is usually preferable to use a powdery raw material of 0.1 to 150 μm, preferably 0.5 to 50 μm, and more preferably 1 to 20 μm. The above-mentioned thermosetting resin is not limited at all, but it is preferable to use a granular or powdery phenolic resin, for example,
(A) Spherical primary particles having a particle size of 0.1 to 150 μm and secondary agglomerates thereof, which are obtained by JP-B-62-30211 or JP-B-62-30213, and (B) at least whole particles.
50% by weight is such a size that it can pass through a 100 Tyler mesh sieve, (C) the methanol solubility defined in the text of the specification is 50% by weight or less, and (D) the value measured by liquid chromatography. The free phenol content is 100 ppm or less. Particular preference is given to granular phenolic resins characterized in that

In the present invention, the above carbon raw material is uniformly mixed with a binder component and then molded into a cylindrical pellet, or a thermosetting resin such as a phenol resin, a melamine resin or a modified product thereof before carbonization. After uniformly mixing the raw material with the binder component, the raw material is shaped into a cylindrical pellet, and then carbonized and activated to obtain a cylindrical pellet-shaped carbon-based adsorbent.

In the present invention, the binder used in the production of the cylindrical pellet-shaped molded product is tar, pitch, liquid phenol resin, liquid melamine resin,
Examples include binders such as polyvinyl alcohol. Also,
The mixture amount of the raw material powder of the carbon material such as plant-based, coal-based, resin-based or the raw material powder of the thermosetting resin such as phenol resin or melamine resin before carbonization or their modified products and the binder is the raw material of the carbon material. With respect to 100 parts by weight of powder or raw powder of thermosetting resin, the binder is usually 5 to 90 parts by weight, preferably 20 to 85 parts by weight, most preferably 30 to
It is preferable to use 80 parts by weight.

The raw material powder of the carbon material or the raw material powder of the resin material and the binder may be mixed as they are,
Alternatively, they may be mixed in the presence of a solvent such as water or an organic solvent. At this time, water, the organic solvent, etc., for example, after the raw material powder of the carbon material or the raw material powder of the resin material and the binder are mixed in advance before being mixed with the binder,
Raw material powder of carbon material or raw material powder of resin material may be added. A solvent such as water or an organic solvent is preferably added in an amount of 5 to 50 parts by weight, more preferably 8 to 30 parts by weight, based on 100 parts by weight of the raw material powder of the carbon material or the raw material powder of the resin material.

When the raw material powder of the carbon material or the raw material powder of the resin material and the binder component are mixed, in addition to these raw materials, for example, an additive such as starch or its derivative or modified product is added to the raw material of the carbon material. It is preferable to add 5 to 50 parts by weight, and more preferably 10 to 40 parts by weight to 100 parts by weight of the raw material powder of the powder or resin material. This additive acts as a pore-forming agent in the cylindrical pellet-shaped carbon-based adsorbent, and contributes to pore formation by thermal decomposition during carbonization in a non-oxidizing atmosphere described later. Specific examples of the additives include, for example, starch such as potato and corn, esterified starch such as acetic acid starch, starch sulfate, and phosphoric acid starch, etherified starch such as hydroxyalkyl starch and carboxymethyl starch, distarch sulfate, and glycerol diester. Examples thereof include starch derivatives such as crosslinked starches such as starch, and starch modified products such as enzyme-modified dextrin. This additive is used in the case of mixing the raw material powder of the carbon material or the raw material powder of the resin material with the binder component, even if they are simultaneously mixed in the form of powder or granules, or in a state of being dispersed in water, or pregelatinized with warm water You may mix at the same time in the state which carried out etc. In the present invention, in addition to the above additives, addition of other additive components is not limited at all, and for example, crystalline cellulose powder, methyl cellulose and the like can be added.

In order to improve workability, a small amount of a surfactant such as ethylene glycol, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polycarboxylic acid ammonium salt, etc. is added within a range that does not impair the characteristics. May be.

The raw material powder of the carbon material or the raw material powder of the resin material and the binder component are usually a ribbon mixer,
It is mixed with a V-type mixer, a cone mixer, a kneader and the like. Then, it is formed into granules by a single-screw or twin-screw wet-extrusion granulator, a vertical granulator such as a basket and a riser, and a semi-dry disk pelleter. The die nozzles of these granulation molding machines can be used to mold cylindrical pellet-shaped molded bodies by using those having a die hole shape for molding into cylindrical pellets having a predetermined inner diameter and outer diameter.

In order to provide the cylindrical pellet-shaped molded body obtained as described above with the adsorption performance as a carbon-based adsorbent, these are usually used as they are, or after carbonization in a non-oxidizing atmosphere, a carbide is formed. The weight reduction rate is 5 to 50
600 to 11 with steam or carbon dioxide within the range of about 10%
Perform activation treatment at 00 ° C, or add zinc chloride, phosphoric acid, potassium hydroxide, potassium sulfide, etc. to the above-mentioned cylindrical pellet-shaped molded product, and then 600 ℃ in a non-oxidizing atmosphere.
This adsorbent can also be produced by heating to ˜1100 ° C. and activation along with carbonization. The non-oxidizing atmosphere in this case is, for example, an inert gas atmosphere such as nitrogen, argon or helium. Further, the temperature rising rate until reaching the maximum processing temperature in the carbonization step is preferably 5 to 30.
It is 0 ° C./hr, more preferably 20 to 100 ° C./hr. The atmosphere at the time of activation is, for example, oxygen, carbon dioxide, water vapor, or a mixed gas of two or more kinds of these, or an atmosphere containing nitrogen, argon, helium, or the like containing these gases.

The temperature of carbonization and activation treatment is preferably 7
The temperature is 00 to 950 ° C, most preferably 750 to 900 ° C. When the temperature of the carbonization and activation treatment is higher than 1100 ° C., the pores that contribute to the adsorption inside the carbonized pellets are thermally shrunk and reduced, so that the adsorption capacity decreases, which is not preferable. If the temperature is lower than 600 ° C, carbonization and activation are not sufficient, and the adsorption capacity is low because the pores involved in adsorption are undeveloped.

The outer diameter d ₁ of the cylindrical pellet-shaped carbonaceous adsorbent obtained by the present invention is 1.0 to 10 mm, preferably 2.0 to 8.
It is 0 mm. If the outer diameter d ₁ is smaller than 1.0 mm, it becomes difficult to form a cylindrical pellet, and since the outer diameter of the pellet is small, the effect of forming the hollow portion at the center to form a void becomes small. In addition, the pressure loss increases, and the flow velocity of the processing fluid cannot be increased, which is not preferable. Outer diameter d ₁ is 10
If it is larger than mm, the voids between pellets increase, the packing density decreases, and the adsorption efficiency decreases, which is not preferable. Further, the inner diameter d of the cylindrical pellet-shaped carbon-based adsorbent obtained by the present invention
₂ is 0.1d _{1 to} 0.5d ₁ , preferably 0.2d _{1 to} 0.4d ₁ . If the inner diameter d ₂ is smaller than 0.1 d ₁ , it becomes difficult to form a cylindrical shape and the flow of fluid at the center of the pellet becomes slow, which is not preferable. If the inner diameter d ₂ is larger than 0.5 d ₁ , the wall thickness of the cylindrical portion is thin and the strength is reduced, and the packing density is reduced, which is not preferable because sufficient adsorption capacity cannot be secured. The length of the cylindrical pellet-shaped carbonaceous adsorbent is
2.0-15 mm, preferably 3.0-10 mm, most preferably 3.
It is 0 to 8 mm, and if the length is shorter than 2.0 mm, the pressure loss at the time of filling becomes high, and powdering easily occurs during use, which is not preferable. If the length is longer than 15 mm, the packing density decreases, and the adsorption efficiency decreases, which is not preferable.

The particle bulk density of the cylindrical pellet-shaped carbon-based adsorbent obtained by the present invention is 0.40 to 1.2 g / cc, preferably
It is 0.60 to 1.1 g / cc. If the particle bulk density is less than 0.40 g / cc, the porosity in the particles increases, the adsorption capacity per unit volume decreases, and the pellet strength also decreases, which is not preferable. On the other hand, if the particle bulk density is larger than 1.2 g / cc, the open pore ratio in the particles becomes too small, the mass transfer rate of the substance to be adsorbed inside the particles becomes slow, and the adsorbing ability decreases, which is not preferable. The pore volume in the range of 0.01 to 10 μm, which can be measured by mercury porosimetry, is 0.10.
˜1.0 cc / g, preferably 0.20 to 0.80 cc / g, most preferably 0.30 to 0.60 cc / g. When the pore volume in the pore diameter range of 0.01 to 10 μm is smaller than 0.10 cc / g, the diffusion speed of the fluid containing the substance to be adsorbed into the particles becomes slow, and the adsorption capacity is lowered, which is not preferable. Also, the pore size is 0.01-10μ
When the pore volume in the range of m is larger than 1.0 cc / g, the residence time of the fluid containing the substance to be adsorbed inside the particles is shortened, the adsorption capacity is lowered, and the bulk density and strength of the pellet are also lowered, which is preferable. Absent. Pore diameter measurable by nitrogen adsorption method 100 Å or less pore volume in the range of 0.20 ~ 1.2cc / g, preferably 0.30 ~ 1.2cc / g, most preferably 0.40 ~ 1.2cc / g
Range. Pore volume of 100 Å or less is 0.20
If it is less than cc / g, the adsorption capacity is low, and if it is more than 1.2 cc / g, the number of pores having a large pore diameter increases, and the bulk density and strength of the pellet decrease, which is not preferable. The specific surface area of the carbon-based adsorbent is usually 100 to 1800 m ² / g, preferably 500 to 1800 m ² / g.

The cylindrical pelletized carbonized adsorbent of the present invention comprises:
The packing density when packed in a packed column or column of the adsorption device changes depending on the particle density and outer diameter, inner diameter, shape such as length, but the packing density range is preferably 0.30 to 0.70 g / c.
c, most preferably 0.40 to 0.65 g / cc. Packing density
If it is less than 0.30 g / cc, the voids between the pellets will be too large and the adsorption efficiency will decrease.If it is greater than 0.70 g / cc, the pressure loss will increase and the mass transfer rate of the adsorbed substance will decrease. Therefore, the adsorption / desorption operation requires a long time, which is not preferable.

[0021]

Since the cylindrical pellet-shaped carbonaceous adsorbent produced as described above has a cylindrical shape, the outer surface area of the adsorbent particles per unit packed bed volume becomes large, and the adsorbent outer periphery and center Since the mass transfer of the fluid containing the substance to be adsorbed from the outer surface of both adsorbents in the void of the part to the inside of the adsorbent occurs, the diffusion distance from the outer surface of the adsorbent of the substance to be adsorbed to the internal adsorption site becomes short, As compared with the conventional granular carbon-based adsorbent, it can exhibit excellent adsorption performance.

The cylindrical pellet-shaped carbonaceous adsorbent of the present invention is
The diffusion distance of the adsorbed substance from the outer surface of the adsorbent to the internal adsorption site can be shortened, the adsorption / desorption operation can be performed more quickly than with ordinary granular pellets, and the equipment capacity will decrease due to pressure loss. Without increasing the outer surface area of the adsorbent particles per unit packed bed volume without increasing the chance of contact with the adsorbed substance and enhancing the adsorption capacity, it is possible to achieve great effects in factories and power plants. Atmospheric purification such as adsorption and removal of sulfur oxides and nitrogen oxides that are processed at a flow rate, and adsorption and removal of nitrogen oxides in automobile tunnels and places where nitrogen oxides are locally discharged such as underground parking lots. It can be used effectively in the system. Further, in addition to air separation of oxygen and nitrogen, butane isomers, hydrocarbon isomer mixtures such as butene isomers, separation of specific gas components from a mixture of ethylene and propylene, separation of various mixed gases,
It can also be used for recovery. Further, when the cylindrical pellet-like carbonaceous adsorbent of the present invention is used for liquid phase adsorption, the water resistance is small due to its large outer surface area, and the diffusion distance of the adsorbed substance from the outer surface to the inner adsorption site is shortened. Since the adsorption / desorption speed of the substance to be adsorbed is high, high-speed processing is possible and the adsorption device can be made compact. Therefore, for example, it can be effectively used for removal of residual chlorine and trihalomethane in tap water, purification of domestic wastewater and factory wastewater, purification of chemical substances, and the like.

(Measurement and Evaluation Method) Next, the measurement and evaluation method used in the present invention will be described below. (1) Pore volume, measurement of pore size distribution Pore volume and pore size distribution of the carbon-based adsorbent of the present invention, for pores in the range of pore diameter 0.01 ~ 1.0 (mu) m, mercury porosimetry method by porosimeter ( It was measured by Shimadzu's Poisizer 9310). For pores with a diameter of 100 Å or less, a fully automatic gas adsorption measuring device (Bellsoap 28, Nippon Bell Co., Ltd.) was used to measure the nitrogen adsorption method. The pores were obtained by DH analysis of the adsorption isotherm of nitrogen gas at 77K, and the pore volume with a pore diameter of 20Å or less is similar to that of the adsorption isotherm.
It was obtained by analysis from t-plot using the MP method. (2) Pellet strength measurement The strength of granulated and activated pellets was measured with a Kiya hardness meter. In the strength measurement, the load when the pellet was broken was measured, and the tensile strength was calculated by the following formula. Tensile strength: σ [kg / cm ² ] = 2P / πdl P: Load [kg] d: Pellet outer diameter [cm] l: Pellet length [cm] (3) Adsorption rate measurement Measure the gas adsorption characteristics of the carbon-based adsorbent. For evaluation, the adsorption rate of each measurement gas was measured by the adsorption characteristic measuring device shown in FIG.

[Fig. 1] In the figure, 3 g of sample was put into the sample chamber (4) (200 ml), valves (11) and (8) were closed, valves (2) and (3) were opened, and degassing was performed for 30 minutes. Close the rear valves (2) and (3), then open the valve (11), introduce a specified gas into the preparation chamber (5) (200 ml), and set the pressure (6.00 kgf / cm ² G). By the way, the valve (11) was closed, the valve (3) was opened, and the change with time of the internal pressure for a predetermined time was measured, converted into an adsorption amount, and the adsorption rate of the gas was obtained. (4) Measurement of air separation ability by pressure swing adsorption (PSA) method In order to evaluate the separation ability of oxygen and nitrogen in the air by the PSA equipment of carbon-based adsorbent, the air separation characteristics are evaluated by the PSA equipment shown in Fig. 2. did.

[Fig. 2] The raw material air supplied by the air compressor (1 ') is dehumidified by the dehumidifier (2'), and then the adsorption tower (3 ') (inner diameter 50 mmφ x 800 mmL) filled with an adsorbent through an automatic valve. )
Alternatively, the adsorption tower pressure is alternately supplied to (3a ′) so that the adsorption tower pressure becomes 7 kgf / cm ² · G. In the adsorption step of each adsorption tower, oxygen in compressed air is adsorbed, and a nitrogen-rich gas is obtained from the outlet of the adsorption tower. When one tower is in the adsorption process, the other tower is in the regeneration process. The operation of the regeneration step is performed by releasing the atmospheric pressure, the adsorbed oxygen is desorbed, and the adsorbent is regenerated. Immediately after the adsorption process of one tower and the regeneration process of the other tower, the pressure equalization process is entered immediately, and immediately after the pressure equalization process is completed, the adsorption tower that was the adsorption process is automatically valved to the regeneration process, and the adsorption tower that was the regeneration process is automatically valved to the adsorption process. Switch by operation. In this way, nitrogen gas can be continuously taken out by repeating the steps of adsorption-pressure equalization (decompression) -regeneration-pressure equalization (pressure increase). Adsorption when supplying a predetermined amount of air - pressure equalization - reproduction - selects the best cycle of pressure equalization, predetermined product gas concentration (N ₂ concentration: 99.9%)
The amount of product gas taken out in was measured, the yield was calculated by the following formula, and the air separation ability was evaluated. (5) was evaluated NO _X adsorbing capability of removing carbonaceous adsorbent at NO _X adsorption removal ability Measurement Figure 3 NO _x adsorption removal ability measurement apparatus shown in.

[Fig.3] Adsorption tower (7 '') (200m) filled with 30cc of sample
l () is kept at 25 ° C by the temperature controller (8 ''), NO (10ppm) / N ₂ gas (1 '') (1kgf / cm ² ) is added to the space velocity: SV
= 10000h ^-1 Flow for 2 hours to adsorb the sample to the adsorption process. After that, the adsorption tower (7 '') was adjusted to 160 ° C by the temperature controller (8 ''), and NO gas (2 '') was added to the SV.
= 10000h ^-1 for 1 hour, and then the sample is desorbed and regenerated for the regeneration process. With this operation as one cycle, the relative humidity of the supply gas is changed to 0%, 30%, and 60%, and each three cycles are evaluated for a total of 9 cycles. The NOx concentration of the gas taken out at the outlet of the adsorption tower during this adsorption step was measured by the NOx analyzer (9``).
To measure. NOx concentration in supply gas and NOx in extraction gas
The NOx adsorption / removal ability was calculated from the concentration, and the average value of 9 cycles was evaluated as the comprehensive NOx adsorption / removal ability. (6) Pressure loss measurement method For pressure loss, the pressure difference per unit height of the packed bed was calculated by measuring the pressure difference between the upper part and the lower part of the tower, which occurs when air is sent to the adsorption tower filled with the adsorbent. Specifically, inner diameter
A 50 mmφ × 800 mmL adsorption tower was filled with an adsorbent, and the tower top and bottom (space 200 m) at 25 ° C and a superficial velocity of 1 m / sec (SV = 4500h ^-1 ).
The pressure loss was obtained by measuring the pressure difference in m). (7) Method for measuring trihalomethane adsorption capacity Chloroform 400 ppb, bromodichloromethane 200 ppb, chlorodibromomethane 800 ppb, bromoform 4000 ppb methanol water standard solution 800 ml was placed in a 1000 ml Erlenmeyer flask, 1.0 g of the sample was added, and the sample was tightly capped, and then at 25 ° C. In a constant temperature shaker
After shaking for 15 minutes, assuming that gas-liquid equilibrium was established in the Erlenmeyer flask, the gas phase concentration in the Erlenmeyer flask after 30 minutes was accurately measured by gas chromatography, and the adsorbent after 30 minutes was measured. The trihalomethane adsorption capacity of was determined. Hereinafter, a specific description will be given with reference to examples.

[0024]

【Example】

Example 1 100 parts by weight of coconut shell charcoal powder (Kintall FY-1 manufactured by Cataler Industry Co., Ltd.) and pitch, degree of polymerization 500, degree of saponification
Measure 99% polyvinyl alcohol (hereinafter abbreviated as PVA) in a specified amount, add 10 parts by weight of water, and use a kneader (KDHJ-20 type manufactured by Fuji Paudal Co., Ltd.) at room temperature for 15
Mix for minutes, then granulate them with a horizontal extrusion granulator (Fuji Paudal Co., Ltd., EXDF-100 type) using a die nozzle with a predetermined hole shape, then at 90 ° C for 16 hours Dried, outer diameter 3.0 mmφ, inner diameter 0.20, as shown in Table 1,
Eight types of cylindrical pellet-shaped compacts of 1.0, 1.5 and 2.4 mmφ were obtained. In addition, as a comparative example, one type of cylindrical pellet granular molding having an outer diameter of 3.0 mmφ was obtained.

[0025]

[Table 1]

Samples 1 to 8 are cylindrical pellets molded to have a predetermined size of hollow shape, and sample 9 is a cylindrical pellet molded for comparison. However, sample 1 could not be granulated because the amount of binder was too small, and sample 2 was able to extrude the kneaded product from the die, but the pellet shape was not very good due to lack of binder. It was In sample 8, the inner diameter of the cylindrical pellet was out of the range specified by the present invention, the wall thickness of the cylindrical portion was thin, and the strength of the pellet was extremely low and it could not be put to practical use. Regarding the cylindrical pellet-shaped molded body samples 2 to 8 and the cylindrical pellet-shaped molded body sample 9 which were capable of granulation,
Using a cylindrical electric furnace with an inner diameter of 70 mmφ, raise the temperature to 850 ° C at a heating rate of 50 ° C / H in a nitrogen atmosphere and then 180
Minute steam activation (Activating gas composition: N ₂ / H ₂ O = 1/1 Flow rate: 1.
5 Nl / min). Table 2 shows the physical properties and characteristic values of the obtained carbonized product.

[0027]

[Table 2]

As can be seen from Tables 1 and 2, in Sample 2 having a small binder component content, the granulated product was P
Although it has strength due to the binder effect of VA, it was found that PVA of the carbonized product was thermally decomposed and most of the binder component was lost, so that the strength decreased and it could not be put to practical use. When the adsorption rate index was evaluated by the following formula using ethane gas using the adsorption characteristic measuring apparatus of FIG. 1, cylindrical samples 2 to 6 were compared with sample 9 in which the equilibrium adsorption amount of ethane gas was columnar. Although the values were almost the same, the adsorption rate index was larger than that of the cylindrical sample 9, and by providing a void in the center of the pellet,
It was found that the adsorption characteristics were improved. However, the sample 7 having an inner diameter smaller than the range specified in the present invention was not much different from the columnar sample 9 in both the equilibrium adsorption amount of ethane gas and the adsorption rate index. Further, Sample 8 having an inner diameter larger than the range specified in the present invention is not preferable because the wall thickness of the cylindrical portion is reduced, the strength is reduced, the packing density is reduced, the adsorption amount of ethane gas is small, and the adsorption performance is low. all right.

Example 2 Phenol-based resin powder (Kanebo Co., Ltd., Bellpar:
100 parts by weight of average particle diameter 20 μm, coal tar (JIS
Standard, K2439-1979, Purification No. 2) 20 parts by weight, liquid melamine resin (Sumitomo Chemical, Sumitex Resin M3, solid content 60%
) 10 parts by weight, 20 parts by weight of PVA having a degree of polymerization of 1700, a saponification degree of 99%, 10 parts by weight of starch, and 10 parts by weight of water are mixed in a kneader, and then these are mixed by a horizontal extrusion granulator at a predetermined rate. Granulation was performed using a die nozzle having a hole shape and then dried at 90 ° C for 16 hours to obtain various types of cylindrical pellet-shaped compacts. These were heated to 850 ° C. at a heating rate of 50 ° C./H in a nitrogen atmosphere in the same manner as in Example 1, and then at this temperature for 18
Steam activation for 0 minutes (Activating gas composition: N ₂ / H ₂ O = 1/1 Flow rate:
1.7 Nl / min) to obtain 12 kinds of cylindrical pellet-like carbonaceous adsorbent. Table 3 shows the pellet size of the obtained carbonized product, workability during molding, and characteristic values. The average length of the carbonized product pellets in this example was 6.0 mm in all the samples.

[0030]

[Table 3]

In Table 3, Samples 10 and 11 having an outer diameter d ₁ smaller than the range of the present invention are not practical because they have extremely poor workability during granulation, low strength, and large pressure loss. . Samples 20 and 21 having an outer diameter d ₁ larger than the range of the present invention
The workability during granulation is relatively good, but in the packed bed, the voids between the pellets are large, the packing density is small, and the adsorption efficiency per unit volume of the packed bed is poor and NOx
The removal rate shows a low value. Samples 13 and 17 having an inner diameter d ₂ smaller than the range of the present invention have a small void in the central portion of the pellet, and therefore the effect of hollowing is small and the NOx removal rate is low. Samples 15 and 19 having an inner diameter d ₂ larger than the range of the present invention have large voids in the central portion, so the wall thickness of the cylindrical portion becomes thin, the strength decreases, the packing density is low, and Poor adsorption performance.

Example 3 A mixture having the same formulation as the sample 14 of Example 2 was mixed, molded and dried, and then heated at a heating rate of 50 ° C./H to 500 ° C., 700 ° C., 850 ° C.
The temperature was raised to 950 ° C and 1200 ° C for carbonization, and steam activation was performed for 180 minutes at each temperature in the same manner as in Example 2. The characteristic values of the obtained carbonized product are shown in Table 4.

[0033]

[Table 4]

The sample 22 having a carbonization activation temperature of 500 ° C. has a small specific surface area and almost no pores are developed. As the temperature increases, the specific surface area increases, and the carbonization activation temperature 950
It became the maximum in sample 24 at ℃. However, the carbonization activation temperature is 12
Since the temperature of Sample 25 at 00 ° C was too high, both the specific surface area and the pore volume became small.

Example 4 In the same manner as in Example 2, 100 parts by weight of phenolic resin powder (Kanebo Co., Ltd., Bellpar R800: average particle diameter 20 μm), coal tar (JIS standard, K2439-197).
9, purified 2) 23 parts by weight, liquid melamine resin (Sumitomo Chemical Co., Sumitex resin M3, solid content 60%) 10 parts by weight, polymerization degree 1700, saponification degree 99% PVA 20 parts by weight, starch 17 parts by weight, And 8 parts by weight of water and kneaded with a kneader, and then these are granulated by a horizontal extrusion granulator using a die nozzle having a predetermined hole shape, dried, and formed into a cylindrical pellet having the same outer diameter. A molded body and a cylindrical pellet-shaped molded body were obtained. These were heated to 800 ° C. at a heating rate of 30 ° C./H in a nitrogen atmosphere in an electric furnace in the same manner as in Example 1, and
After holding for a period of time, it was cooled to obtain a cylindrical pellet carbon adsorbent having an outer diameter of 3.0 mm and an inner diameter of 1.0 mm and a cylindrical pellet carbon adsorbent having an outer diameter of 3.0 mm. The adsorption rate of oxygen and nitrogen was measured for each of the obtained samples using the adsorption characteristic measuring apparatus shown in FIG. As an index showing the adsorption characteristics of oxygen and nitrogen, the adsorption amount 1 minute after the start of adsorption is Q ₁ for nitrogen and Q ₂ for oxygen, and the adsorption amount difference ΔQ is calculated by the following formula ΔQ = Q ₂ −Q ₁ . Also, assuming that the nitrogen adsorption pressure is P ₁ (kgf / cm ² ), and the oxygen adsorption pressure is P ₂ (kgf / cm ² ), the selection coefficient α is the following equation α = (Q ₂ / P ₂₎ / (Q ₁ / P _Calculated from ₁₎ . Further, an air separation experiment was conducted using the PSA evaluation device shown in FIG. Table 5 shows the shape comparison values and characteristic values of the carbonized products, and Table 6 shows the PSA operating conditions.

[0036]

[Table 5]

[0037]

[Table 6]

In Table 5, the cylindrical pellet sample 26 has a larger outer surface area of the adsorbent particles per unit filling volume than the cylindrical pellet sample 27, and shows the best characteristics in PSA evaluation.

Example 5 In the same manner as in Example 2, 100 parts by weight of a phenolic resin powder (manufactured by Kanebo Co., Ltd., Belpar R800: average particle size 20 μm), liquid melamine resin (manufactured by Sumitomo Chemical, Sumitex Resin) M3, solid content 60%) 36 parts by weight, polymerization degree 500, saponification degree 99
% PVA (34 parts by weight), starch (23 parts by weight), and water (7 parts by weight) in a kneader, and these are granulated using a horizontal extrusion granulator using different die nozzles, and then dried to obtain a shape, Granular pellets of different sizes were obtained. In the same manner as in Example 1, these were heated at a heating rate of 50 ° C./H in a nitrogen atmosphere.
The temperature is raised to 00 ° C, then to 900 ° C at a heating rate of 100 ° C / H, and steam activation is performed at this temperature for a predetermined time (activating gas composition: N ₂ / H ₂ O = 1/1 flow rate: 2.5Nl / min) to obtain 5 types of cylindrical pellet-shaped carbon-based adsorbents and cylindrical pellet-shaped carbon-based adsorbents with an outer diameter of 4 mm. These trihalomethane (THM) adsorption capacities were evaluated by the method described above. Table 7 shows the physical property values and measurement results of the carbon-based adsorbent.

[0040]

[Table 7]

In Table 7, the sample 28 having a short activation time is
It can be seen that the weight reduction rate is as low as 12%, the value of the specific surface area is smaller than that of the other samples, the volume of pores with a pore diameter of 100 Å or less is small, and the THM adsorption capacity is also small. Further, the sample 30 having a long activation time, the weight reduction rate is relatively large,
THM adsorption capacity is also large. Particularly, in the case of the cylindrical pellet-shaped sample 33 and the cylindrical pellet-shaped sample 29 having the same outer diameter, the sample 29
Has a higher THM adsorption capacity. Since Sample 29 is in the form of a cylindrical pellet, it has an advantage over a cylindrical pellet due to its large outer surface area and short diffusion distance to the adsorption site in adsorption operations for a limited time. it is conceivable that.

Example 6 Raw materials having the same blending amount as in Example 4 were mixed with a kneader, and then these were granulated by a horizontal extrusion granulator using a die nozzle having a predetermined hole shape, Dried, different outer diameter
We obtained three types of cylindrical pellet-shaped compacts and two types of cylindrical pellet-shaped compacts with different outer diameters. Using an electric furnace similar to that used in Example 1, these were heated at a heating rate of 50 ° C./H in a nitrogen atmosphere.
The temperature is raised to 00 ° C and then to 870 ° C at a heating rate of 100 ° C / H and steam activation (activating gas composition:
N ₂ / H ₂ O = 1/1 flow rate: 2.0 Nl / min) to obtain 3 types of cylindrical pellet-shaped carbon-based adsorbents and 2 types of cylindrical pellet-shaped carbon-based adsorbents. These were filled in an adsorption tower, and an evaluation experiment of NOx adsorption removal ability was conducted. Table 8 shows the experimental results and the physical properties of the carbon-based adsorbent.

[0043]

[Table 8]

In Table 8, sample 36 in the form of a cylindrical pellet has higher NOx than sample 37 in the form of a cylindrical pellet having the same outer diameter.
The removal rate was shown.

[Brief description of drawings]

FIG. 1 is an adsorption characteristic measuring device for evaluating the adsorption characteristic of a carbon-based adsorbent in the present invention.

FIG. 2 is a pressure swing adsorption (PSA) device for evaluating the air separation characteristics of a carbon-based adsorbent according to the present invention.

FIG. 3 is a NO _x adsorption / removal capacity measuring device for evaluating the NO _x adsorption / removal capacity of the carbon-based adsorbent in the present invention.

[Explanation of symbols]

1 Vacuum pump 2, 3, 8, 11, 12, 13 Valve 4 Sample chamber 5 Adjustment chamber 6, 7 Pressure sensor 9 Recorder 10 Pressure gauge 14, 15 Gas regulator 1'Compressor 2'Air dryer 3 ', 3a' Adsorption Towers 4 ', 4a', 6 ', 7', 7a ', 8', 10 ', 1
0a ', 15' Automatic valve 5 ', 5a', 9 ', 9a', 11 ', 12' Piping 13 'Surge tank 14' Oxygen sensor 1 '' Nitrogen cylinder 2 '' NO cylinder 3 '', 4 '' Gas regulator 5 '' Humidity controller 6 '' Gas mixing tower 7 '' Adsorption tower 8 '' Temperature controller 9 '' NOx sensor 10 '' Humidity sensor 11 '', 12 '', 13 '', 14 '' Valve 15 '' flow meter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C01B 31/02 101 B01J 2/20 31/10 B01D 53/34 129A // B01J 2/20

Claims (1)

[Claims] 1. The outer diameter d ₁ is 1.0 to 10 mm and the inner diameter d ₂ is 0.1 d ₁ to
A total of 80 cylindrical pellets with a diameter of 0.5d ₁ and a length of 2.0 to 15 mm
%, And the pore volume in the pore diameter range of 0.01 to 10 μm is 0.10 to 1.0 cc / g, the pore volume in the pore diameter range of 100 Å or less is 0.20 to 1.2 cc / g, and the particle bulk density is Is 0.40 to 1.2 g /
A cylindrical pellet-shaped carbon-based adsorbent having a carbon content in the range of cc and 90% by weight or more.