JP2003190783A - Adsorbent for solvent vapor and method for preparing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorbent for solvent vapor large in an amount of adsorbed solvent vapor and excellent in abrasion resistance and mechanical strength. <P>SOLUTION: The purpose is achieved by attaching silica and/or alumina of 1-40% by weight to an activated active carbon of 0.1-20 mm in an average particle diameter. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adsorbent for solvent vapor such as gasoline and alcohol, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a method of recovering the organic solvent from a gas body containing volatilized solvent vapor, after adsorbing the solvent through the above-mentioned gas body to an activated carbon layer filled with molded activated carbon, this activated carbon layer is A method of heating and adsorbing the adsorbed solvent again is performed. Further, in a gasoline engine of a car, when the driving engine is stopped, the heat around the engine, which was high in temperature until then, is transferred to the surroundings, and becomes a so-called hot soak state, and gasoline vapor is generated. Various adsorbents have been proposed for adsorbing this gasoline vapor and releasing it again during engine operation for use.

For example, Japanese Unexamined Patent Publication (Kokai) No. 2-167809 discloses an activated carbon having a large butane effective adsorption amount by specifying packing density, pore volume, surface area, average pore diameter and the like. Japanese Unexamined Patent Publication (Kokai) No. 6-9208 discloses activated carbon having a specific apparent density and a large butane treatment amount.
Japanese Unexamined Patent Publication No. 2001-152025 discloses a polymer-coated wear-resistant activated carbon for butane adsorption. Further, Japanese Patent Application Laid-Open No. 6-129312 proposes an alcohol-based fuel vapor adsorbent obtained by mixing powdered alumina or powdered silica with powdered activated carbon, molding and firing.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The adsorbents proposed in Japanese Patent Publication No. 809, Japanese Unexamined Patent Publication No. 6-9208, and Japanese Unexamined Patent Publication No. 6-129312 have some improvement in adsorption ability for a specific solvent vapor, but wear resistance and mechanical resistance. The strength is not always sufficient,
Therefore, when these adsorbents are mounted on an automobile or the like which is constantly exposed to constant vibration, the adsorbents may be worn or pulverized. Further, the adsorbent coated with the polymer proposed in Japanese Patent Laid-Open No. 2001-152025 has a lower butane adsorption capacity in the coating. Under such circumstances, an object of the present invention is to provide a solvent vapor adsorbent having a high solvent vapor adsorbing ability and excellent in abrasion resistance and mechanical strength, and a method for producing the same.

[0005]

As a result of intensive studies to obtain an adsorbent that solves the above-mentioned problems, the present inventors have found that a specific amount of silica and / or alumina is added to activated carbon that has already been sufficiently activated. It has been found that the adsorbent obtained by impregnating with is capable of adsorbing a large amount of solvent vapor, and has high wear resistance and mechanical strength. The present invention has been completed by further studies based on this finding. That is, the present invention provides (1) a solvent vapor adsorbent obtained by impregnating 1 to 40% by weight of silica and / or alumina with activated activated carbon having an average particle size of 0.1 to 20 mm, and (2) activated activated carbon,
Specific surface area 800-2500 m ² / g, pore volume 0.3-
The solvent vapor adsorbent according to (1), which has a packing density of 2.0 ml / g and a packing density of 0.2 to 0.7 g / ml, and (3) activated activated carbon is granular activated carbon having an average particle diameter of 0.5 to 15 mm. The solvent vapor adsorbent according to (1) or (2), (4) the solvent vapor adsorbent according to (1) or (2), wherein 2 to 30% by weight of silica and / or alumina is impregnated. )
The solvent vapor adsorbent according to any one of (1) to (4) for a vehicle canister, (6) average particle size 0.1 to 2
A liquid containing silica and / or alumina in 0 mm activated carbon is used as silica and / or alumina in an amount of 1 to
A method for producing a solvent vapor adsorbent in which 40% by weight is uniformly mixed and dried under heating to impregnate silica and / or alumina. (7) Activated activated carbon has a specific surface area of 8
00-2500 m ² / g, pore volume 0.3-2.0 ml
/ G, the packing density is 0.2 to 0.7 g / ml, (6) The production method according to (6), wherein the activated carbon is a granular activated carbon having an average particle diameter of 0.5 to 15 mm (6). Alternatively, the production method according to (7), (9) the liquid containing silica and / or alumina is uniformly mixed in an amount of 2 to 30% by weight as silica and / or alumina, (6) or (7). The production method, and (10) the production method according to (6) or (7), wherein the liquid containing silica is an aqueous solution of water glass.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The activated activated carbon used in the present invention is not particularly limited, and a gas activation method in which a raw material carbon is activated using an activated gas such as steam, oxygen, air, carbon dioxide, or the like. Chemicals that activate coking coal in the presence of chemicals that have dehydrating and eroding effects on alkali metal hydroxides such as potassium hydroxide, sodium hydroxide and sodium hydroxide, and raw materials such as zinc chloride, phosphoric acid, sulfuric acid and calcium chloride. It can be obtained by an activation method or the like. In the present invention, those activated by chemicals are more preferable, and those activated by phosphoric acid and zinc chloride are particularly preferable.

[0007] The raw coal may be any carbon source used as a usual activated carbon raw material, for example, wood, wood flour, coconut shell, by-products during pulp production, bacas, molasses, peat, lignite. , Lignite, bituminous coal, anthracite, petroleum distillation residue components, petroleum pitch, coke, coal tar and other plant-based raw materials and fossil-based raw materials, phenol resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, melamine resin, urea resin, Examples include various synthetic resins such as resorcinol resin and polyamide resin, synthetic rubbers such as polybutylene, polybutadiene and polychloroprene, and carbonized synthetic wood and synthetic pulp. Among these activated carbon raw materials, plant raw materials such as wood, wood powder and coconut shell, and coal-based raw materials such as brown coal, bituminous coal and anthracite are preferably used.

Examples of the method for carbonizing the activated carbon raw material include known production methods such as a fixed bed method, a moving bed method, a fluidized bed method and a rotary kiln method. Examples of the carbonization method include a method of firing in an atmosphere of an inert gas such as carbon gas, carbon dioxide, helium, argon, xenon, neon, carbon monoxide, and combustion exhaust gas.

The activated carbon used in the present invention has an average particle size of 0.1 to 20 mm, preferably 0.5 to 15 m.
m, specific surface area (BET) is 800 to 2500 m ² / g, preferably 1000 to 2300 m ² / g, and pore volume (displayed as N ₂ adsorption amount when relative pressure is 0.931 by N ₂ adsorption method). 0.3-2.0 ml / g, preferably 0.35
~ 1.8 ml / g, more preferably 0.4-1.6 m
1 / g, packing density is 0.2 to 0.7 g / ml, preferably 0.25 to 0.5 g / ml. A liquid containing silica and / or alumina is added to the activated carbon.
Silica and / or alumina were adhered to the surface of activated carbon and inner walls of pores by spraying on the surface of activated carbon while mixing, or by immersing activated carbon in a liquid and pulling it up to uniformly mix, and then drying. Activated activated carbon is obtained. Among them, the spraying method is preferable. The liquid containing silica may be, for example, a liquid in which fine silica powder is suspended, or a solution of silica sol, silica gel, sodium silicate (water glass), or potassium silicate. Among these, water glass is particularly preferable. Water glass is converted to silica by impregnating activated carbon and drying. These solutions may be diluted with water or a solvent to an appropriate concentration before use. As the liquid containing alumina, for example, activated alumina, alumina sol, alumina gel fine powder suspended in water, aluminum hydroxide colloid liquid diluted to an appropriate concentration, and the like can be mentioned. Aluminum hydroxide also becomes alumina in the drying process.

The amount of silica and / or alumina impregnated on the activated carbon is 1 to 40% by weight, preferably 2 to 30% by weight, as silica and / or alumina.
Further preferably, it is 2 to 19% by weight. Drying is usually performed under heating, preferably at 90 to 200 ° C, more preferably 100 to 150 ° C. By impregnating the activated carbon with silica and / or aluminum, the inner wall surface of the fine pores of the activated carbon is coated with silica or alumina having solvent vapor adsorption ability, whereby the pore diameter is adjusted to a more appropriate range, As a result, the adsorption performance of solvent vapor is improved,
Moreover, it is considered that the abrasion resistance and the mechanical strength are enhanced.

The solvent vapor adsorbents of the present invention are hydrophilic and
Excellent adsorption and desorption ability for any hydrophobic solvent vapor
Show. Examples of hydrophilic solvents include methanol and ethanol.
1 to 8 carbon atoms such as knoll, propanol and butanol
(Hereinafter C_1-8As shown. ) Alcohol, meth
C such as ruketone and ethyl ketone_3-5The ketones
Which can be mentioned. As the hydrophobic solvent, for example, C_Four~
C₈Chain aliphatic saturated or unsaturated hydrocarbons of C,₅~ C₉
Cycloaliphatic hydrocarbons, C₆~ C₉Aromatic hydrocarbons,
C₁~ C ₆Halogenated hydrocarbon, C_Four~ C₈Ete
Le, C₅~ C₇Ketone, C_Three~ C₈Esters, etc.
You can C above_4-8Chain aliphatic saturated or unsaturated charcoal of
Examples of hydrogen fluoride include n-butane, n-pentane, and n.
-Hexane, isohexane, n-heptane, n-octa
,, isooctane (2,2,4-trimethylpenta
), 2,2-dimethylbutane, 2-pentene, etc.
To be

Examples of the C _{5 to} C ₉ cycloaliphatic hydrocarbons include cyclohexane and methylcyclohexane. Examples of the C _{6 to} C ₉ aromatic hydrocarbons include benzene, toluene, O-xylene, m-xylene, p-xylene, ethylbenzene and isopropylbenzene. Examples of the C ₁ -C ₆ halogenated hydrocarbon include methylene chloride, chloroform, carbon tetrachloride, ethyl chloride, ethylene chloride, ethylidene chloride, 1,1,1-trichloroethane, 1,1,2-
Trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2, -tetrachloroethane, pentachloroethane, vinylidene chloride, 1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, 1,
2,3-trichloropropane, isopropyl chloride, allyl chloride, 1,2-dichloropropane, butyl chloride, amyl chloride, o-chlorotoluene, p-chlorotoluene and the like can be mentioned.

Examples of the C _{4 to} C ₈ ether include ethyl ether, n-butyl ether, epichlorohydrin, diglycidyl ether, furan and the like. Examples of the C _{5 to} C ₇ ketone include methyl n
-Propyl ketone, methyl n-butyl ketone, methyl isoptyl ketone, methyl n-amyl ketone, diethyl ketone, ethyl n-butyl ketone, cyclohexanone, o
-Methylcyclohexanone and the like. C ₃ above
Examples of the C ₈ ester include acid ethyl, propyl formate, n-butyl formate, isobutyl formate, amyl formate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, butyl acetate and acetic acid. n
-Amyl, isoamyl acetate, ethyl acetate.

In the adsorbent of the present invention, hydrophilic silica or alumina covers at least a part of the inner wall of the pores of the activated activated carbon, and as a result, not only the gas of the hydrophobic solvent such as gasoline but also the hydrophilicity such as alcohol. Adsorption / desorption performance of solvent vapor is also enhanced. In addition, by filling the macropores of activated carbon that do not contribute to adsorption with silica / alumina, it is possible to suppress the temperature rise during adsorption and also to increase the adsorption amount. Moreover, since the adsorbent of the present invention has improved mechanical strength and abrasion resistance, it is particularly useful as a gas adsorbent / desorbent in automobile canisters using gasoline or alcohol as fuel.

[0015]

EXAMPLES The present invention will be described in more detail with reference to the following examples and test examples.

Example 1 (1) Preparation of Activated Activated Carbon 120-130 ° C. while mixing 1300 g of coconut shell powder (dry product) and an aqueous zinc chloride solution (1040 g as zinc).
The mixture was heated to react. The weight of each mixture is 90-1
The reaction was stopped when the content reached 15% by weight, and each of the obtained reaction products was press-molded at 130 ° C. into a shape having a diameter of 30 cm and a thickness of about 4 mm, put into a crucible, and activated by firing at 600 ° C. for 3 hours. . The obtained baked product is washed with hydrochloric acid according to a conventional method,
It was washed with water to remove unreacted zinc chloride and then dried. The dried material was pulverized to 0.6 to 1.7 mm to obtain activated activated carbon having an average particle diameter of 1.05 mm, a specific surface area of 1310 m ² / g, a pore volume of 0.879 ml / g and a packing density of 0.369 g / ml. Obtained. The average particle size is JIS K
The weight ratio (particle size distribution%) obtained from 1474 "particle size distribution" was multiplied by the arithmetic mean diameter (opening mm) of the sieve section, and the product was integrated as shown in the following formula. Average particle size (mm) = Σ [(particle size distribution%) X (arithmetic mean opening mm) X 1/100)]

(2) 180 g of activated carbon obtained by impregnating silica (1) was put in a rolling granulator and rotated while water glass (Wako Pure Chemical Industries, Ltd.).
180 g of water glass aqueous solution (containing 8 g as silica) prepared by diluting sodium silicate aqueous solution) with distilled water
Was uniformly sprayed and dried at 115 ° C. for 12 hours.
By this drying, silica-activated 4% by weight activated carbon having the physical properties shown in Table 1 was obtained.

Example 2 160 g of activated carbon and 170 g of aqueous solution of water glass
Silica 8 having the physical properties listed in Table 1 in the same manner as (2) of Example 1 except that (containing 14 g of silica) was used.
A weight% impregnated activated carbon was obtained.

Example 3 (1) Preparation of Activated Activated Carbon for Coal Raw Material Commercially available activated carbon (W5c10 / 4, manufactured by Takeda Pharmaceutical Co., Ltd.)
2) (coal-based steam activated carbon) is additionally activated at 900 ° C. for 1 hour in a steam atmosphere, and raw material activated carbon (average particle size 1.
03 mm, specific surface area 1123 m ² / g, pore volume 0.9
21 ml / g, packing density 0.368 g / ml) was obtained.
By the same method as in Example 1, 4% by weight of silica was impregnated on this activated carbon to obtain activated activated carbon.

Example 4 In the same manner as in Example 2, activated carbon activated with 8% by weight of silica was obtained.

Test Example 1 Measurement of Effective Adsorption of Ethanol Using the apparatus shown in FIG. 1, ethanol for each of the raw material activated carbon and the silica impregnated activated carbon obtained in Examples 1 to 4 according to the following procedure. The effective adsorption amount was measured. The results are shown in Table 1. 1. The sample adsorbent was dried at 150 ° C. for 3 hours and returned to room temperature in a desiccator. 2. Place the sample on a glass column (6) with an inner diameter of 15.4 mm (2).
It was filled with 0 ml and set in an incubator (5) at 25 ° C. 3. The constant temperature bath (4) was set to 24 ° C and ethanol (9
An ethanol generation bottle (3) containing 9.9% or more) was put thereinto, and 350 ml / min of nitrogen gas was introduced from the nitrogen cylinder (1) to generate ethanol vapor. 4. The generated ethanol vapor is passed through the glass column (6) filled with the sample in an upward flow, and the flammable gas detector (XP
-311A Adsorbed until the gas detection concentration of New Cosmos Electric Co., Ltd. (8) became 55% (15050 ppm), and the glass column (6) was removed and weighed (Ag). 5. After the adsorption, the glass column was set in the apparatus again, and the dry air (25 ° C.) generated from the dry air generator (9) in the downward flow was fed with 670 ml / min (33.5 BEDvol).
/ Minute) for 17 minutes 54 seconds to remove the glass column,
Weighed (Bg). 6. The above 2. ~ 5. The above operation was repeated 4 times, and the final desorption amount was multiplied by 5 to obtain the effective ethanol adsorption amount (g
/ DL). Ethanol effective adsorption amount (g / dL) = (Ag-Bg) X
5

Test Example 2 Measurement of Effective Adsorption of n-Butane Using the apparatus shown in FIG.
The raw material activated carbon and the silica impregnated activated carbon obtained in Example 4 were used as samples, and the effective adsorption amount of n-butane was measured for each of them. The results are shown in Table 1. 1. The sample was dried at 150 ° C. for 3 hours and returned to room temperature in a desiccator. 2. Glass column with inner diameter of 15.4 mm (14)
20 ml was filled in and set in an incubator (13) at 25 ° C. 3. Butane cylinder (11) to n-butane (purity 99.
(9% or more) to the glass column (14) with an upward flow of 250 m
After circulating for 15 minutes at a flow rate of 1 / min, the glass column (14) was removed and weighed (Cg). 4. The column after adsorption was set in the device again, and the dry air generated from the dry air generator (16) in the downward flow was used.
20 ml / min (25 ° C) (10 BEDvol / min)
After circulating for minutes, the glass column (14) was removed and weighed (Dg). 5. The above operation was performed and the desorption amount was multiplied by 5 to obtain the butane effective adsorption amount (g / dL). n-butane effective adsorption amount (g / dL) = (Cg-Dg) X
5

Test Example 3 Measurement of amount of fine powder For the same sample used in Test Example 1, the following method was used.
The amount of fine powder generated from the sample was measured. 1. Membrane filter pore size 0.45μm, diameter 25
mm (Advantech Toyo Co., Ltd.) 1 at 115 ° C
It was dried for an hour and weighed (Eg). 2. A 150 ml sample was weighed (Fg) and washed with water to remove fine powder adhering to the activated carbon surface. 3. The washed sample was thoroughly drained, put in a 300 ml beaker, 250 ml of water was added, and the mixture was stirred for 3 hours at a rotation speed of 100 rpm by a jar tester (manufactured by Pure Water Industry Co., Ltd.). 4. After stirring, the supernatant in the beaker was filtered with a weighed membrane filter. 5. The activated carbon and membrane filter collected by filtration are 115
It was dried at ℃ for 2 hours and weighed (Hg). Amount of fine powder (% by weight) = (Hg-Eg) / FgX100

Test Example 4 Hardness Test According to JIS K 1474, the hardness of the same sample as used in Test Example 1 was measured. The results are shown in Table 1.

[0025]

[Table 1]

As is clear from the results shown in Table 1,
The silica-impregnated activated carbons of Examples 1 to 4 showed a larger amount of ethanol vapor and n-butane effective adsorption amount than the respective raw material activated activated carbons, and further showed higher abrasion resistance and mechanical strength.

[0027]

The solvent vapor adsorbent of the present invention exhibits excellent adsorptivity to vapors of both hydrophilic and hydrophobic solvents, but particularly to vapors of hydrophilic solvents such as ethanol. Shows high adsorption capacity. Further, since the adsorbent of the present invention is excellent in wear resistance and mechanical strength, even when it is installed in a place that constantly vibrates, such as an automobile canister, the adsorbent particles are abraded and powdered to form a gas. Distribution is not hindered. Further, the adsorbent of the present invention may be simply added to silica and / or alumina and then dried, which is advantageous in production.

[0028]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an ethanol effective adsorption measurement test circuit for an adsorbent.

FIG. 2 is a schematic diagram showing an n-butane effective adsorption measurement test circuit for an adsorbent.

[Explanation of symbols]

1: Nitrogen cylinder 2: Nitrogen flow meter 3: Ethanol generation bottle 4: constant temperature bath 5: Incubator 6: Column 7: Activated carbon 8: Combustible gas detector 9: Dry air generator 10: Flow meter 11: Butane cylinder 12: Flowmeter for butane 13: Incubator 14: Column 15: Activated carbon 16: Dry air generator 17: Flow meter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Yoshidome             2-17-85 Jusohonmachi, Yodogawa-ku, Osaka-shi, Osaka Prefecture             No. Takeda Pharmaceutical Co., Ltd.             In the knee (72) Inventor Juichi Yanagi             2-17-85 Jusohonmachi, Yodogawa-ku, Osaka-shi, Osaka Prefecture             No. Takeda Pharmaceutical Co., Ltd.             In the knee F-term (reference) 4G066 AA05B AA05C AA20B AA20D                       AA22A AA22B AA22D AA37D                       BA20 BA25 BA26 CA04 CA51                       DA04 FA03 FA12 FA18 FA21                       FA37

Claims (10)

[Claims] 1. Activated activated carbon having an average particle diameter of 0.1 to 20 mm and 1 to 40% by weight of silica and / or alumina.
Solvent vapor adsorbent formed by attachment. 2. The activated carbon has a specific surface area of 800 to 250.
0 m ² / g, pore volume 0.3~2.0ml / g, solvent vapor adsorbent according to claim 1, wherein those having a bulk density 0.2 to 0.7 g / ml. 3. The activated carbon having an average particle diameter of 0.5 to 15 is used.
The solvent vapor adsorbent according to claim 1 or 2, which is a granular activated carbon of mm. 4. Silica and / or alumina in an amount of 2 to 30
The solvent vapor adsorbent according to claim 1 or 2, wherein the solvent vapor adsorbent is impregnated in a weight percentage. 5. A vehicle canister for a vehicle, wherein:
The solvent vapor adsorbent according to any one of 1. 6. A liquid containing silica and / or alumina is uniformly mixed with activated activated carbon having an average particle diameter of 0.1 to 20 mm in an amount of 1 to 40% by weight as silica and / or alumina. A method for producing a solvent vapor adsorbent, which comprises drying under heating and impregnating silica and / or alumina. 7. The activated activated carbon has a specific surface area of 800 to 250.
The production method according to claim 6, which has a pore volume of 0 m ² / g, a pore volume of 0.3 to 2.0 ml / g, and a packing density of 0.2 to 0.7 g / ml. 8. The activated carbon having an average particle diameter of 0.5 to 15 is used.
The method according to claim 6 or 7, which is a granular activated carbon of mm. 9. The method according to claim 6, wherein the liquid containing silica and / or alumina is uniformly mixed in an amount of 2 to 30% by weight as silica and / or alumina. 10. The method according to claim 6, wherein the liquid containing silica is an aqueous solution of water glass.