JPH0576754A - Molded composite adsorbent and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Object] To provide an activated carbon-hydrated alumina composite shaped adsorbent having a combination function excellent in adsorption and desorption of organic components, particularly vaporized fuel having a low boiling point, and a method for producing the same. [Structure] A molded product of a homogeneous mixture of 30 to 80% by weight of powdered activated carbon having an average pore radius of less than 13Å and 20 to 70% by weight of pseudo-boehmite hydrated alumina, the molded product being 900 m ² / g. Larger BET specific surface area,
A molded composite adsorbent having an average pore radius of 10 Å or more and less than 13 Å. [Effect] C3 to C contained in vaporized fuel such as gasoline
It has an excellent ability to adsorb low boiling point components such as 4 and methanol, and also has an improved combination of saturated adsorption amount and effective desorption rate, and is remarkable for the deterioration of adsorption and desorption performance during long-term use. A composite shaped adsorbent of activated carbon and hydrated alumina having resistance can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite adsorbent composed of a molded product of a mixture of activated carbon and hydrated alumina, and a method for producing the same, and more specifically to an adsorbability of organic components, particularly vaporized fuel having a low boiling point. TECHNICAL FIELD The present invention relates to a composite molded adsorbent having an excellent combination of a desorption property and a desorption property and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, granular activated carbon has been widely used as an adsorbent for adsorbing organic solvent vapors in the air and various hydrocarbon vapors. This granular activated carbon shows a high adsorptivity for organic components, but it is not always easy to desorb once adsorbed components, and at the time of desorption, for example, a method of heating a packed bed of granular activated carbon and passing steam A method of heating the packed bed and passing a gas therethrough is adopted.

However, if the adsorbent is heated during regeneration, there is a risk that the adsorbent will burn, and desorbing the adsorbent in the normal atmosphere and at room temperature is also a workability and safety point. But it is a great hope.
Further, granular activated carbon generally has low mechanical strength and abrasion resistance, and has a problem of dust generation, and its black color also causes problems of mounting and environmental pollution.

[0004] Japanese Patent Laid-Open No. 1-29 related to the proposal of the present inventors
3134 discloses powdered activated carbon 30 to 70% by weight.
And a homogeneous mixture of 30 to 70% by weight of pseudo-boehmite hydrated alumina, 500 to 700 g /
A composite adsorbent characterized by a packing density of 1 and an average pore radius of 13 to 21Å is described.

[0005]

The above activated carbon-hydrated alumina composite molded article adsorbent has a remarkably excellent combination of adsorption and desorption with respect to components to be adsorbed, such as organic components, and particularly effective desorption amount. Also, it has the advantage that the adsorbed components can be easily desorbed by using room temperature and atmospheric air, and that it has remarkably excellent mechanical strength and wear resistance. But C3 to C
It has the disadvantage of poor adsorption performance for low boiling point components such as four components.

[0006] Recently, a so-called M-85 having a composition of 85% methanol and 15% gasoline has been studied as an alcohol fuel for automobiles. However, there are still points to be improved.

The present inventors have succeeded in producing a molded composite adsorbent having a small average pore radius and a large BET specific surface area from a mixture of powdered activated carbon and pseudo-boehmite,
This product has a combination of a saturated adsorbing amount and a desorbent, which has an excellent adsorbing property for low boiling point components of C3 to C4, methanol, etc., and this composite adsorbent is not subject to forced deterioration due to gasoline dripping. It was found that there is a marked resistance to this, and the deterioration of adsorption and desorption performance is extremely small.

That is, the object of the present invention is to have an excellent ability to adsorb low boiling point components such as C3 to C4 contained in air and methanol, and to improve the combination of saturated adsorption amount and effective desorption rate. (EN) An active carbon-hydrated alumina composite molded adsorbent having a remarkable resistance to deterioration of adsorption and desorption performance during long-term use and a method for producing the same.

[0009]

According to the invention, molding of a homogeneous mixture of 30 to 80% by weight of powdered activated carbon with an average pore radius of less than 13 Å and 20 to 70% by weight of pseudo-boehmite hydrated alumina. The body consists of 900m
BET specific surface area larger than ² / g and 10 Å or more 13
A shaped composite adsorbent is provided having an average pore radius of less than Å.

The molding compound of the present invention, as a molding aid,
A total of 0.1 to 10% by weight of synthetic or natural smectite clay mineral can be contained.

Also according to the invention, 30 to 80% by weight
Powdered activated carbon having an average pore radius of less than 13Å of 20 to 7
0% by weight of pseudo-boehmite-type hydrated alumina was uniformly kneaded in the presence of water, and the resulting kneaded product was mixed with 50 to 55
Molded into a spherical or cylindrical molded body having a water content of wt% and a diameter of 0.5 to 1.5 mm, subjecting the molded body to a rolling treatment under rolling conditions, and then at 100 to 120 ° C. A method for producing a molded composite adsorbent is provided, which comprises calcination at a temperature of 200 to 400 ° C. after drying.

[0012]

The composite adsorbent of the present invention comprises a molded product of a homogeneous mixture of powdered activated carbon and pseudo-boehmite hydrated alumina, which molded product has a BET of more than 900 m ² / g.
The first feature is that it has a specific surface area and an average pore radius of 10 Å or more and less than 13 Å.

Generally, the amount of adsorption and desorption of gasoline, methanol, etc. in the adsorbent is closely related to the average pore radius of the adsorbent. Granular activated carbon having a small average pore radius of 10 to 13Å has a large adsorption amount for the above organic components, but has a small effective desorption amount for the adsorbed organic components. On the other hand, those having a large average pore radius such as activated alumina have a small amount of adsorption to the above-mentioned effective components, but have a large amount of effective desorption of the adsorbed organic components.
As described above, regarding the average pore radius of the adsorbent used, the effective adsorption amount and the effective desorption amount are incompatible with each other, and it is generally difficult to increase both of them.

In the above-mentioned prior art, the average pore radius of the activated carbon-alumina-based composite adsorbent is 13 to 20 Å, especially 1 to 10 Å as compared with the average pore radius of 10 to 13 Å of the granular activated carbon.
By increasing rather than 4 to 18Å, the effective desorption amount of the adsorbed organic component is increased.
However, the increase of the average pore radius in the composite adsorbent is due to the adsorption performance for low boiling point components such as C3 to C4 components in vaporized fuels such as gasoline, and adsorption for methanol components in alcohol fuels for automobiles. Performance will inevitably decrease.

In the present invention, the average pore radius of the activated carbon-alumina-based composite adsorbent is set to 10 Å or more and 13 Å similar to that of granular activated carbon.
And a BET specific surface area of 900
By increasing to a range larger than m ² / g, the adsorbability of the above-mentioned adsorbed components is improved, while significantly improving the adsorption performance for organic components, particularly low boiling point components such as C3 to C4 components of vaporized fuel and methanol components. It is possible to increase the amount of desorption.

The fact that the composite adsorbent of the present invention exhibits an excellent effective desorption amount while having excellent adsorption performance for the above-mentioned low boiling point components has been found as an experimental result. , The alumina component from pseudo-boehmite-type hydrated alumina coexisting with activated carbon promotes the desorption of the organic component adsorbed on the activated carbon, and in the low boiling point component mentioned above, the adsorption / desorption itself is higher than the heavier component. It is estimated that this is because it is easy.

Next, the BET specific surface area of the composite adsorbent is set to 90.
A range larger than 0 m ² / g and an average pore radius of 10 Å
In order to obtain a small range of less than 13Å, powdered activated carbon having an average pore radius of less than 14Å was selected and used as the active carbon component, and this was granulated by homogeneously mixing it with pseudo-boehmite hydrated alumina. Is a feature of.

As the activated carbon component, those having an average pore radius of less than 14 Å are of course known, and it is already known to use granular activated carbon having an average pore radius in the above range as an adsorbent for canisters. .. However, while the activated carbon having the above average pore radius has a large adsorption amount,
In contrast to the drawback that the effective desorption amount is small, the present invention succeeds in improving the effective desorption amount to a remarkably high level while maintaining the adsorption amount at a large level.

[0019]

Preferred Embodiment of the Invention

(Composite Adsorbent) The composite adsorbent of the present invention comprises a molded product of a homogeneous mixture of powdered activated carbon and pseudo-boehmite hydrated alumina. Pseudo-boehmite-type hydrated alumina shows remarkably excellent forming during the formation of powdered activated carbon, and at the time of heat treatment (calcination) of the formed body, it gives a strong and dense formed body due to its shrinkage, and The activated alumina itself has excellent adsorption performance.

In the composite adsorbent of the present invention, powdered activated carbon is 3
0 to 80% by weight, especially 40 to 60% by weight and 20 to 70% by weight of pseudo-boehmite hydrated alumina, especially 40
To 60% by weight, respectively. When the amount of the powdered activated carbon is less than the above range or the amount of the pseudo-boehmite hydrated alumina is more than the above range, the adsorption amount and the effective desorption amount tend to be lower than in the case of the present invention, while the powdered activated carbon is used. Is slightly higher than the above range, or if the amount of pseudo-boehmite hydrated alumina is less than the above range, the strength of the molded article tends to decrease and the effective desorption amount tends to decrease.

The preferred formulation depends on the application. For example, as an adsorbent for a gasoline vehicle canister, an activated carbon-rich adsorbent, that is, powder activated carbon in an amount of 50 to 70% by weight and pseudo-boehmite hydrated alumina in an amount of 50 to 30% by weight, while an adsorbent for an alcohol fuel vehicle canister is used. Alumina-rich agent, that is, activated carbon powder is 4
0 to 50% by weight and 6 of pseudo-boehmite hydrated alumina
Amounts from 0 to 50% by weight are preferred.

The composite adsorbent of the present invention has a BET specific surface area of more than 900 m ² / g, especially 1000 to 3000.
It has a BET specific surface area of m ² / g and has an average pore radius of 10 Å or more and less than 13 Å, particularly 10 to 12 Å. Also, this composite adsorbent is preferably 0.1.
4 to 0.6 g / cc, especially 0.45 to 0.5 g / c
With a packing density of c, the packing density of the granular activated carbon is generally 0.3 to 0.4 g / cc, which is a large packing density and increases the adsorption amount and effective desorption amount per unit volume. To help.

The adsorbents of the present invention generally have 0.5 to 1.
It is desirable that the molded body has a spherical or cylindrical shape having a diameter of 5 mm. In general, the smaller the particle size, the longer the breakthrough time when the fuel gas starts to leak without being adsorbed. On the other hand, if the particle size of the adsorbent is too small, the pressure loss when passing through the packed bed increases. In the above particle size range, the fuel gas can be effectively adsorbed with a relatively small pressure loss.
Further, in the above particle shape, the strength of the particles is high and the wear resistance is also excellent. Adsorbents for gasoline vehicle canisters have a relatively small particle size of 0.5 to 1.1 mm, while adsorbents for alcohol fuel vehicle canisters have a relatively large particle size of 1.1 to 1.5 mm. Those are preferable.

Further, this composite adsorbent is excellent in mechanical strength and wear resistance, and is 0.5 when measured by a Kiya type hardness meter.
It exhibits a crush strength of not less than kg, especially not less than 1 kg. Therefore, this composite adsorbent does not generate dust or the like and is used stably over a long period of time even when the adsorption-desorption cycle is repeated, and also under the motion condition where mechanical vibration is applied. It has the feature that it can.

The composite adsorbent of the present invention has a total amount of 1. in addition to the above powdered activated carbon and pseudo-boehmite hydrated alumina.
It is desirable to contain 0 to 10% by weight, especially 2 to 5% by weight of natural or synthetic smectite. That is, when smectite is blended, the mechanical strength and abrasion resistance can be remarkably improved without substantially lowering the adsorption-desorption performance described above.

(Raw material) As already pointed out, in the present invention, pseudo-boehmite type hydrated alumina is used as the alumina adsorbent component. As aluminum hydroxide or hydrated alumina, boehmite gel (pseudo-boehmite) is known in addition to gibbsite, vialite, boehmite, and diaspore. Of these, pseudoboehmite is used as the alumina raw material in the present invention.

The hydrated alumina used in the present invention is generally 5
Particle size of less than μm, especially less than 3 μm and 200 to 400 m
BET specific surface area of ² / g and 0.3 to 0.6 ml / g
Those having a pore volume of Generally, pseudo-boehmite hydrated alumina is produced by reacting sodium aluminate with a mineral acid such as sulfuric acid or by reacting an aluminum salt such as aluminum aluminum sulfate with an alkali such as caustic soda. Even hydrated alumina produced by a known general production method can be used for the purpose of the present invention if it satisfies the above requirements. Hydrated alumina which is advantageously used for the purpose of the present invention is Japanese Patent Publication No.
It is manufactured by the method described in Japanese Patent No. 13652 and the same method. The hydrated alumina used as the raw material has the formula

Embedded image In the formula, Al ₂ O ₃ .xH ₂ O, x is a number of 1.0 to 2.0, and particularly 1.4 to 1.8. It is preferable to have a composition of

The powdered activated carbon used as the other raw material has an average pore radius of less than 13Å. This activated carbon has a BET specific surface area of generally 10 μm or less, particularly 8 μm or less, 1300 m ² / g or more, especially 1400 m ² / g or more, and 0.8 to 1.5 ml / g, particularly 0.9 to 1. It preferably has a pore volume of 3 ml / g.

The powdered activated carbon selectively used in the present invention is one having a small average pore radius, in other words, one having a high specific surface area and a high pore volume, and is generally a graphite layer which highly activates coals. It is said to be a single layer, and BET
Those with a specific surface area of 3000 to 4000 m ² / g (there may be a problem applying the BET formula because the theoretical maximum value of the specific surface area of activated carbon is 2600 m ² / g) have already been manufactured and marketed. ing.

Suitable examples of such high pore volume activated carbon are:
Examples include super activated carbon manufactured by Osaka Gas Co., Ltd., high surface area activated carbon (microsorb) manufactured by Kansai Thermal Chemical Co., Ltd., high surface area activated carbon manufactured by Mitsubishi Kasei Co., Ltd. (for example, CQN-2), and the like.

If desired, natural or synthetic smectite clay minerals used as the third component include dioctahedral smectites such as montmorillonite, beidellite and nontronite, and trioctaoctanes such as saponite, hectorite, sauconite and stevensite. A helical smectite can be used. These smectite group clay minerals themselves have adsorptivity, and also have an action as an inorganic binder to improve the mechanical strength and wear resistance of the molded product. Particularly preferred are acid clay or activated clay belonging to montmorillonite,
Synthetic layered magnesium phyllosilicate described in JP-A-61-10020, synthetic frypontite described in JP-A-61-10021, active bentonite described in JP-A-63-50310, Japanese Patent Application No. 62-20476. The synthetic stevensite and the like described in the publication can be mentioned. These clay minerals preferably have a particle size of generally 10 μm or less, particularly 3 μm or less, and a BET specific surface area of 200 to 600 m ² / g, particularly 200 to 500 m ² / g.

(Production Method of Composite Adsorbent) According to the present invention, the composite adsorbent has an average pore radius of 1 to 30 to 80% by weight.
Powdered activated carbon of less than 4Å and 20 to 70% by weight of pseudo-boehmite hydrated alumina were homogeneously kneaded in the presence of water, and the resulting kneaded product had a water content of 50 to 55% by weight and a density of 0. Molded into a spherical or cylindrical molded body having a diameter of 5 to 1.5 mm, subjecting the molded body to rounding under rolling conditions, and then drying at 100 to 120 ° C., then 250 to 4
It is manufactured by calcining at a temperature of 00 ° C.

First, the above-mentioned raw materials in the above-mentioned composition ratio are
Mix in the presence of water to homogenize the whole. Water content of activated carbon powder is 30 to 50% for homogeneous mixing
And a pseudo-boehmite-type hydrated alumina having a water content of 5 to 10% are sufficiently mixed in an inert atmosphere such as steam or nitrogen. This mixture is kneaded in the presence of water for homogenization and then molded into a predetermined shape. A kneader, a super mixer, a single-screw or twin-screw extruder or the like can be used for the kneading operation, and a vacuum-type kneader can be used if necessary. For molding the granules, various molding machines known per se, for example, an extrusion molding machine, a tableting machine, a rolling granulator and the like can be used. Generally, the kneading and molding is preferably carried out by an extruder, and the kneading is preferably carried out in at least one stage, preferably in multiple stages. In multi-stage kneading and molding, the particle size of extrusion molding can be gradually reduced.

In the method of the present invention, when the kneaded product is molded, it can be molded into a spherical or cylindrical molded product having a limited water content of 50 to 55% by weight and a diameter of 0.5 to 1.5 mm. is important. If the water content is lower than the above range, the molded product tends to be powdered, and it becomes difficult to produce a composite adsorbent having a high packing density and a high particle strength. On the other hand, when the water content is higher than the above range, the molded product tends to agglomerate, has a clear particle shape and a uniform particle size, and may produce a composite adsorbent having high particle strength. It will be difficult.

Although not generally required, if desired, an organic binder known per se in the composition, for example, carboxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, starch, cyanoethylated, is added to the kneading composition in order to impart shape retention. Starch, tragacanth rubber, various synthetic resins and latexes of synthetic rubber can be added in an amount of 0.1 to 3% by weight based on the solid content.

According to the invention, the compact thus shaped is subjected to rounding under rolling conditions. By this rounding treatment, the granulated compact after molding is chamfered, and the voids in the granulated compact are compressed to form a densified uniform structure. The number of rotations when rolling the molded body is not particularly limited as long as the above treatment is effectively performed, but the number of rotations is generally 10 to 500.
It should be in the rpm range.

The rounded granular moldings are subjected to a drying treatment at a temperature of 100 to 120 ° C. and then 200 to 4
Calcination at a temperature of 00 ° C. Drying at the above temperature prior to calcination is important for obtaining a dense and excellent composite adsorbent, and at a temperature lower than the above range, water is not sufficiently removed. There is a tendency for foaming during calcination, and at temperatures higher than the above range, there is a tendency for foaming during drying due to rapid removal of water. The purpose of calcination is to make the composition densified and strengthened by baking, and at the same time to convert pseudo-boehmite hydrated alumina into highly active alumina. In addition, in the composite adsorbent of the present invention, the pseudo-boehmite type structure is preserved even after the conversion to high activity alumina. When the temperature of the heat treatment is lower than the above range, the densification due to quenching is insufficient, the conversion into highly active alumina is insufficient, and the durability becomes poor. On the other hand, when the heat treatment temperature is higher than the above range, the surface activity of the adsorbent tends to decrease. The calcination treatment is generally 60 to 360 minutes, especially 1
It can be performed by heating for 20 to 240 minutes.

[0038]

[Use] The composite adsorbent of the present invention has an initial saturated adsorption amount of vaporized fuel (n-C4) of 20 g / 300 cc or more, particularly 20 to 24 g /, as measured by the measuring method described in Examples below.
It has a remarkable characteristic that it is 300 cc and the effective desorption rate of the adsorbed fuel is 50% or more, and particularly 52 to 60%.

Due to this characteristic, the composite adsorbent of the present invention is
It is particularly useful as a canister adsorbent for various fuels, especially as a canister adsorbent for vehicles that use gasoline or alcohol fuel. Further, the composite adsorbent of the present invention can be widely used in various applications for removing and recovering organic solvent vapors, hydrocarbon vapors, chlorofluorocarbons and the like by adsorption from various atmospheres, and various solutions. It is also used as an adsorbent for removing odorous components, colored components, etc. from a dispersion liquid by adsorption.

[0040]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, the measurement of powder properties of adsorbents and the like in Examples and Comparative Examples was performed by the following test methods.

(1) Test method 1. X-Ray Diffraction In this example, an X-ray diffractometer manufactured by Rigaku Denki Co., Ltd. (X-ray generator 4036A1, goniometer 2125) was used.
D1, counting device 5071) was used. The diffraction conditions are as follows. Target Cu filter Ni detector SC voltage 35kV current 15mA count full scale 8000c / s time constant 1sec scanning speed 2 ° / min chart speed 2cm / min radiation angle 1 ° slit width 0.3

2. BET specific surface area (SA) Automatic N ₂ manufactured by CARLO-ERBA
Adsorption device (Sorptomatic Series 1
800) and calculated by the BET formula.

3. Pore volume Automatic N ₂ made by CARLO-ERBA
Adsorption device (Sorptomatic Series 1
After 2hr degassed at 10 ^-2 mmHg, 250 ° C. with 800), temperature of liquid nitrogen, N ₂ in N ₂ pressure 735mmHg
The N ₂ adsorption amount (V1) in the standard state was calculated from the adsorption amount, and the pore volume was calculated from the following formula.

## EQU1 ## Pore volume (PV) = V1 × 1.555 × 10 ^-3 (ml / g)

4. Average pore radius (r) Assuming that the pores are cylindrical, the average pore radius (r) is calculated from the following formula.
I asked.

[Equation 2] Average pore radius (r) Å = 2 x pore volume (PV) x 10 ⁴ / BET specific surface area (SA)

5. Packing density A sample of predetermined weight (Wg) dried at 150 ° C for 3 hours was put into a 500 ml graduated cylinder, and after well tapping, the packing volume (Vml) of the sample was measured and the packing density (BD) was calculated from the following formula. I asked.

(3) Packing density (BD) = W / V × 1000 (g / l)

6. Particle Strength Using a Kiya type hardness meter (10 kg meter), the crushing strength of 20 samples dried at 250 ° C. for 2 hours was measured, and the average value was taken as the particle strength.

7. Abrasion resistance 40 g of a sample that has been subjected to a moisture absorption treatment for 48 hours under a relative humidity of 75% is a soaker (manufactured by Red Devil, 5410).
Glass container (45 mm diameter x 75 m) set in the mold
m), the mixture was dipped for 30 minutes and classified with a 42-mesh sieve, the passing weight (W1) was measured, and the abrasion resistance rate was calculated from the following formula.

[Equation 4] Abrasion resistance = (40−W1) × 100/40 (%)

8. Average particle size Coulter Count method
er, Model TA-2 type), the particle size determined from the 50% volume distribution point of the cumulative particle size curve was taken as the average particle size.

(2) Pseudo-boehmite-type hydrated alumina The pseudo-boehmite-type hydrated alumina used in the present invention was prepared by the method described below. Calcium carbonate concentration of 70 to 30 under conditions of heating and stirring at 70 to 120 ° C
In a 0 g / l slurry (hereinafter referred to as charcoal slurry),
A slightly acidic (pH 2 to 3) aluminum nitrate solution having a concentration of 50 to 100 g / l as Al ₂ O ₃ was added at a rate of 100 to 1000 ml / min, and the pH of the reaction slurry after the addition was 6 to 8; The hydrated alumina was obtained by aging treatment for about 1 hour while slowly stirring at a temperature of 90 ° C. or lower. Then, filter and wash with water at 110 ℃ to 1 ℃.
The hydrated alumina fine powder used in the present invention was dried at 50 ° C. and its properties are shown in Table 1.

[0050]

[Table 1]

(3) Powdered Activated Carbon As the activated carbon used in the present invention, among the commercially available products, those having a specific surface area of 1300 m ² / g or more are preferably used. The properties of the powdered activated carbon (Kansai Thermochemical Co., Ltd., Mitsubishi Kasei Co., Ltd.) used in the present invention are shown in Table 2.

[0052]

[Table 2]

(4) Forming Aid In the present invention, a natural or synthetic smectite type clay mineral having a binder property can be used as a forming aid. The molding aid used in the present invention is shown in Table 3.

[0054]

[Table 3]

Example 1 Powdered activated carbon, pseudo-boehmite-type hydrated aluminum and a molding aid were dry-mixed in the amounts shown in Tables 1 and 2, and then kneaded and kneaded while controlling the humidity with a kneader. After being homogeneously kneaded to have a water content of 50 to 60% by weight, extrusion-granulated into a particle size of 0.5 to 1.5 mm (EXD-60 manufactured by Fuji Paudal), the obtained columnar shape Was tumbled at 100 rpm for 2 minutes, then primary dried at 100 to 150 ° C., then 200
Secondary drying at ~ 400 ℃, water content 0 ~ 5wt%
A shaped composite adsorbent according to the present invention was prepared. Table 4
The properties of the 1.0 mm-diameter adsorbent obtained by the above test method are shown in FIG.

(Example 2) Using the composite adsorbent according to the present invention obtained in Example 1, 85 vol% of methanol (containing 15 vol of commercial gasoline, hereinafter M-
85) and n-butane gas (purity 99%) were adsorbed and desorbed.

(Test method-1) 3 filled with composite adsorbent
0.5 L / min of n-butane gas was passed through a packed bed of 00 ml, and the adsorption amount was determined from the weight increase of the composite adsorbent when the breakthrough amount of n-butane gas reached 0.2 g. Next, after passing an air at a flow rate of 5 L / min through the adsorbent packed bed for 20 minutes, the weight loss was measured to obtain the desorption amount, and the adsorption and desorption were determined by
Table 5 shows the adsorption amount for the first time and the adsorption amount and desorption amount for the sixth time (six cycles) in the results.
The desorption rate in the sixth cycle of adsorption and desorption was calculated by the following formula.

## EQU00005 ## Desorption rate (%) = desorption amount / (desorption amount + remaining amount) × 100 = (D / E) × 100

(Test method-2) 3 filled with composite adsorbent
The adsorbed amount was determined by increasing the weight of the composite adsorbent when the amount of M-85 breakthrough reached 0.2 g was passed through an atmosphere saturated with 0.5 L / min of M-85 vapor through a packed bed of 00 ml. Next, after passing an air at a flow rate of 5 L / min through the adsorbent packed bed for 20 minutes, the weight loss was measured to obtain the desorption amount, and the adsorption and desorption were repeated 6 times. As a result, the first adsorption amount and the 6th time were determined. Table 5 shows the adsorption amount and desorption amount (at 6 cycles). The desorption rate in the sixth cycle of adsorption and desorption was calculated by the above "Equation 5".

[0059]

[Table 4]

[0060]

[Table 5]

[0061]

[Table 6]

(Test Method-3) Run No. 6
In the composite adsorbent (cylindrical article), the composite adsorbents having different molding particle diameters were experimentally manufactured, and the adsorption performances were compared based on Test Method-1. The results are shown in Table 7.

[0063]

[Table 7]

Example 3 The physical properties of the composite adsorbent of the present invention obtained in Example 1 were measured by the above-mentioned measuring methods. The results are shown in Table 8.

[0065]

[Table 8]

[0066]

According to the present invention, 30 to 80% by weight of powdered activated carbon having an average pore radius of less than 13Å and 20 to 70% by weight are used.
Granules formed of a molded body of a homogeneous mixture with wt% pseudo-boehmite-type hydrated alumina and having a BET specific surface area of more than 900 m ² / g and an average pore radius of 10 Å or more and less than 13 Å. When used as a composite adsorbent, it has excellent ability to adsorb low boiling point components such as C3 to C4 contained in air and methanol, and has an improved combination of saturated adsorption amount and effective desorption rate. Moreover, it has been possible to provide a composite molded adsorbent of activated carbon and hydrated alumina, which has remarkable resistance to deterioration of adsorption and desorption performance during long-term use.

Claims (6)

[Claims] 1. Mean pore radius 13 of 30 to 80% by weight
A compacted body of a homogeneous mixture of less than Å activated carbon powder and 20 to 70% by weight of pseudo-boehmite hydrated alumina,
A molded composite adsorbent characterized in that the molded body has a BET specific surface area of more than 900 m ² / g and an average pore radius of 10 Å or more and less than 13 Å. 2. The molded composite adsorbent according to claim 1, which contains a synthetic or natural smectite-type clay mineral in an amount of 1.0 to 10% by weight as a molding aid. 3. The molded composite adsorbent according to claim 1, wherein the initial saturated adsorption amount of the vaporized fuel n-butane is 20 g / 300 ml or more and the effective desorption rate of the adsorbed fuel is 50% or more. 4. Average pore radius 13 of 30 to 80% by weight
A powdered activated carbon of less than Å and 20 to 70% by weight of pseudo-boehmite-type hydrated alumina were uniformly kneaded in the presence of water, and the resulting kneaded product had a water content of 50 to 55% by weight and a water content of 0. A spherical or columnar mixture having a diameter of 5 to 1.5 mm is molded into a molded body, the molded body is subjected to a rolling treatment under rolling conditions, and then dried at 100 to 120 ° C.
A method for producing a molded composite adsorbent, which comprises calcination at a temperature of 0 to 400 ° C. 5. A pseudo-boehmite hydrated alumina having a particle size of 5 μm or less, a BET specific surface area of 200 to 400 m ² / g and a pore volume of 0.3 to 0.6 ml / g. The method for producing the molded composite adsorbent according to claim 4. 6. The activated carbon powder having a B content of 1300 m ² / g or more.
The method for producing a molded composite adsorbent according to claim 4, which has an ET specific surface area and a pore volume of 0.8 to 1.5 ml / g.