JPH05200284A - Laminated adsorbent - Google Patents

Abstract

PURPOSE:To obtain an adsorbent excellent in adsorption performance and form retentivity by arranging a plurality of sheets of sintered sheets made of activated carbon in a layer so that the voids are formed between the respective sintered sheets to produce a laminated adsorbent and providing holes for passing gas to be treated in the respective sintered sheets. CONSTITUTION:In a laminated adsorbent wherein a plurality of sheets of sintered sheets 1, 3 made of activated carbon are arranged in a layer so that the voids are formed between the respective sintered sheets, holes 5 for passing gas to be treated are provided in the respective sintered sheets 1, 3. Further the voids are formed by alternately laminating the corrugated sintered sheets 3 and the planar sintered sheets 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated adsorbent for fluid treatment, which has excellent adsorption properties.

In this specification, "%" and "part" mean "wt%" and "part by weight", respectively.

[0003]

2. Description of the Related Art Conventionally, as an adsorbent, an active carbon fiber formed into a felt shape has been known.
Activated carbon fibers are widely used because of their high adsorption rate and large adsorption amount per unit weight. However, when the activated carbon fiber is formed into a felt shape, it becomes bulky and difficult to handle, and when it is packed in a large amount in an adsorption tower or the like, the pressure loss of the introduced fluid increases. Also occurs.

Japanese Examined Patent Publication No. 59-3205 proposes an adsorption device in which a plurality of paper-like materials obtained by mixing activated carbon fibers and other kinds of fibers are arranged in layers at intervals. In this adsorption device, a non-adsorbed substance contained in the fluid is adsorbed and removed by introducing a fluid between these paper-like objects in parallel with the paper-like object surface, so the above-mentioned felt-like objects are used. Compared to the adsorption device
It is said that the pressure loss can be reduced.

[0005]

However, in an adsorption device using a paper-like material obtained by mixing the above-mentioned activated carbon fibers and other kinds of fibers, the presence of fibers having no adsorption ability leads to an increase in adsorption efficiency. There is a problem of lowering it. Further, in the case of producing an adsorbent having a small dimension in the flow direction of the treatment fluid for use as a deodorizing filter, it is necessary to make a number of paper-like objects into strips and stack them, so that the shape-retaining property is unsatisfactory. There is a problem that it is sufficient and the manufacturing cost is high.

The main object of the present invention is to provide a laminated adsorbent having excellent adsorption performance and excellent shape retention.

[0007]

Means for Solving the Problems As a result of intensive research in view of the problems of the prior art as described above, the present inventor formed a sintered sheet provided with gas circulation holes using activated carbon, It has been found that the purpose can be achieved when a plurality of sintered sheets are laminated and used with a constant spacing.

That is, the present invention provides the following laminated adsorbent: A laminated adsorbent in which a plurality of sintered sheets of activated carbon are arranged in layers so that voids are formed between the respective sheets, and each of the sintered sheets has holes for passing a processing gas. And a laminated adsorbent.

2. 2. The laminated adsorbent according to item 1 above, wherein voids are formed by alternately laminating corrugated sintered sheets and planar sintered sheets.

3. 2. The laminated adsorbent according to item 1, wherein voids are formed by laminating a plurality of sintered sheets having protrusions formed thereon.

The activated carbon used in the present invention may be in any form such as fibrous or powdery form. In particular, when fibrous activated carbon is used, a high strength sintered body can be obtained by using a small amount of binder based on structural characteristics such as entanglement of fibers and high strength in the fiber direction. preferable. As fibrous activated carbon,
Although not particularly limited, as the properties before sintering,
Ordinary fiber diameter 2 to 30 μm, fiber length 0.05 to 10
It is preferable to use one having a size of about mm, a pore size of about 5 to 20 Å, and a specific surface area of about 500 to 2500 m ² / g. Granular activated carbon has an average particle size of 10 to 10
A fine particle having a specific surface area of about 0 μm and a specific surface area of 500 m ² / g or more is preferable from the viewpoint of adsorption / desorption characteristics.

The origin of the activated carbon is not particularly limited, either.
It may be any of coal-based, petroleum-based, phenolic resin-based, PAN-based, cellulose-based, coconut husk-based, wood-based and the like. A sintered sheet of activated carbon is produced by mixing 100 parts of activated carbon with 20 parts or less of a binder as needed, more preferably about 2 to 20 parts, uniformly mixing, molding, and sintering. It It is not necessary to use a binder if a sintered sheet having sufficient strength can be obtained even if the activated carbon alone is sintered.

When a binder is used, a material that is integrated with activated carbon by a sintering operation (hereinafter referred to as a sinterable binder) is particularly suitable, and more specifically, infusible carbon (for example, raw material pitch). Infusibilized carbon), thermosetting resin (aramid resin, phenol resin,
Examples thereof include epoxy resin, urea resin, etc., and infusible heat-melting resin (infusible acrylic resin, infusible polyvinyl alcohol resin, etc.). Furthermore, when the sinterable binder is used in the form of a thread (for example, when the raw material pitch is spun and the infusibilized unfired carbon fiber is used), the ratio of blocking the pores of the activated carbon is Less.
As the filamentous sinterable binder, the thread diameter is 5 to 100 μm.
It is preferable to use one having a length of about 0.1 to 5 mm.

If necessary, the activated carbon or the blend of the activated carbon and the binder may be added to 50 parts per 100 parts of the activated carbon.
A reinforcing material up to about a part may be further added. Examples of such additives include natural fibers such as hemp and paper pulp, and heat-fusible fibers such as polyethylene yarn and polypropylene yarn.

The adsorbent of the present invention is manufactured, for example, as follows. First, activated carbon alone or a uniform mixture of activated carbon and a sinterable binder or a temporary molded product containing a reinforcing material is put into a mold and the pressure is about 5 to 1000 kgf / cm ² (more preferably about 10 to 300 kgf / cm ^2). ), A temperature of about 500 to 1500 ° C. (more preferably 700 to 1)
A sintered sheet is manufactured by sintering under conditions of about 100 ° C.

If the pressure applied during sintering is less than 5 kgf / cm ² and / or if the sintering temperature is less than 500 ° C., sintering will be insufficient and only products with low strength and low density will be produced. I can't get it. If the sintering temperature exceeds 1500 ° C,
There is a tendency that the pore structure of the activated carbon changes and the proportion of pores blocked by the sinterable binder increases, and the adsorption performance of the sintered sheet decreases. Pressurized pressure is 1000kgf / cm ²
If it exceeds, the pores of the activated carbon may be destroyed and the adsorption performance of the sintered sheet may be reduced.

The sintering time may be appropriately selected according to the type of activated carbon used, the shape of the molded body, the type and amount of the sinterable binder, etc., but is usually in the range of about 5 seconds to 30 minutes. is there.

Alternatively, when fibrous activated carbon is used, a low-density preformed body prepared in advance by a dry method or a wet method may be sintered. In the case of the wet method, activated carbon alone, a uniform mixture of activated carbon and a sinterable binder or a mixture containing a reinforcing material is dispersed in water and mechanically stirred to prepare a uniform aqueous slurry, which is then sucked. A mold having a mouth is placed in an aqueous slurry and suctioned to obtain a preform. After drying this preform, it may be put in a mold and sintered under the same conditions as above. Further, when fibrous activated carbon is used, the activated carbon may be preliminarily formed into a non-woven fabric by a dry method in a mold and sintered under the same conditions as above. When these preforms are used, handling becomes easy and uneven density can be prevented. In particular, when a preform formed by a wet method is used, the unevenness of the areal weight is small and the uneven density of the sintered sheet is also small, which is preferable.

The thickness of the sintered sheet is preferably about 0.1 to 5 mm, more preferably about 0.3 to 1 mm. If the thickness of the sintered sheet exceeds 5 mm, the thickness becomes too large and the activated carbon present inside may not be effectively utilized. Further, when the thickness of the sintered sheet is less than 0.1 mm, there is a drawback that required strength cannot be obtained.

The sintered sheet obtained by the above method has a very high density of 0.4 g / cm ³ or more, and most of it is composed of activated carbon.
Excellent adsorption capacity and high strength.

The adsorbent of the present invention is composed of a plurality of sintered sheets obtained as described above, and is laminated so that there is a constant space between the respective sintered sheets. Due to the existence of this interval, it becomes possible to flow and process the liquid containing the substance to be adsorbed between the sintered sheets with a low pressure loss.

The method for forming the gap is not particularly limited, but for example, as shown in the schematic sectional view of FIG. 1, a flat sintered sheet 1 and a corrugated sintered sheet 3 are used. A space can be formed by alternately stacking the layers. These sintered sheets are provided with a large number of vent holes 5, ... 5 for passing the processing gas. The size of the vent holes 5, ... 5 may be appropriately determined depending on the pressure loss, the adsorption characteristics of the sintered body, etc., but normally the diameter is about 0.2 to 20 mm,
More preferably, it is about 0.5 to 5 mm. Vents 5, ...
The total area of No. 5 is preferably about 0.1 to 20% of the area of the sintered sheet, and more preferably about 1 to 10%. This value may be appropriately determined by comprehensively considering the pressure loss, the adsorption property, the sheet strength and the like. The ventilation holes 5, ... 5 may be formed in a regular pattern or may be formed randomly. The interval formed between the planar sintered sheet 1 and the corrugated sintered sheet 3 (the interval between the peaks and valleys of the corrugated sintered sheet 3) is appropriately selected depending on the usage conditions of the adsorbent and the like. However, considering the magnitude of pressure loss and the length of the adsorbent, it is usually about 0.1 to 5 mm, more preferably about 0.2 to 2 mm. If the spacing between the sintered sheets is less than 0.1 mm, the pressure loss will increase,
On the other hand, when it exceeds 5 mm, the packing density of activated carbon is low and the diffusion resistance of the adsorbed substance is large, and as a result, the adsorbed substance is likely to break through.
If it is attempted to prevent this, the length of the adsorbent also becomes large, which is also impractical.

In the present invention, as shown in a schematic sectional view in FIG. 2, a plurality of sintered sheets 1, ... 1 provided with a large number of projections 7 ,. Examples of such protrusions are shown in plan views in FIGS. Vents 5, ...
5 may be formed similarly to the embodiment shown in FIG. Such protrusions can be integrally formed together with the sintering process of the sintered sheet.

In the sintered sheet 1 shown in FIG. 3, circular protrusions 7, ... 7 are formed in rows and columns. These protrusions may also be formed in a regular pattern or may be formed randomly. However, in the laminated adsorbent body using this type of sintered sheet, it is preferable that the vent holes 5, ... And the protrusions 7 ,. Height of protrusions 7, ... 7 (planar sintered sheets 1, 1
(Corresponding to the spacing formed between) also usually has a diameter of 0.1 to
It is about 5 mm, more preferably about 0.2 to 2 mm. When the sintered sheet 1 is viewed as a plan view, the proportion of the projections 7, ... 7 is preferably 50% or less of the planar area of the sintered sheet 1, and more preferably 20 to 5%.

The sintered sheet 1 shown in FIG. 4 is provided with linear projections 9, ... Also in the laminated adsorbent using this type of sintered sheet, it is preferable that the vent holes 5, ... 5 And the projections 9 ,. The area occupied by the projections 7, ... 7 is the same as above.

[0026]

According to the present invention, the following remarkable effects are achieved.

(1) Since a high-density sintered sheet obtained by sintering is used, the activated carbon is different from the case of using a sheet in which a conventional heat-fusible binder is heated to near its melting point and fused. The pores of No. 1 remain without being blocked. Also. Very high activated carbon content. Therefore, the obtained sintered sheet exhibits excellent adsorption performance.

(2) An adsorbent obtained by laminating the above-mentioned sintered sheets in layers at specific intervals is
It can process various fluids with low pressure loss, and its adsorption performance is also extremely excellent. Further, it is also excellent in shape retention as a laminated adsorbent.

(3) Since the laminated adsorbent according to the present invention can be reduced in size in the flow direction of the processing fluid (that is, can be reduced in thickness), it can be downsized.

(4) Particularly when fibrous activated carbon is used, a sintered sheet and an adsorbent having even higher strength can be obtained due to the entanglement of fibers and high strength in the fiber length direction. .

(5) The laminated adsorbent according to the present invention having the above-mentioned characteristics (2) and (3) specifically realizes miniaturization of various deodorizing filters, ozone filters, masks and the like. .

[0032]

EXAMPLES Examples and comparative examples will be shown below to further clarify the characteristics of the present invention.

Example 1 98 parts of pitch-based activated carbon fiber having a specific surface area of 1000 m ² / g (trademark “A-10”, manufactured by Adol Co., Ltd.) and 2 parts of an acrylic resin-based binder as a binder were dispersed in water. Beating was carried out until the carbon fiber length was almost all 5 mm or less to obtain a uniform slurry.

Then, the above slurry was put into a flat mold having a large number of suction ports at the bottom and suction was carried out to obtain a flat type wet molding sheet (100 mm with a basis weight of about 360 g / m ² ).
(× 100 mm), the pressure is 50 kg / cm ² ,
By maintaining the temperature at 930 ° C. for 20 seconds, the thickness of 0.
A flat plate-shaped sintered sheet having a size of 5 mm and a bulk density of 0.6 g / cm ³ was obtained.

Further, the wet-molded sheet manufactured in the same manner as above was placed in a mold having a very gentle wave shape, and the pressure of 50 kg / cm ² was applied by a press machine, and 93
By holding at 0 ° C. for 20 seconds, a corrugated sintered sheet having a thickness of 0.5 mm and a bulk density of 0.6 g / cm ³ was obtained. The obtained corrugated sheet has a height difference of 0.4 mm between peaks and valleys.
And the distance between the peaks was 5 mm.

Then, circular vent holes having a diameter of 2 mm were randomly formed in the flat plate-shaped sintered sheet and the corrugated sintered sheet obtained as described above. The total area of the ventilation holes was 10% of the sintered sheet.

The flat plate-shaped sintered sheet and the corrugated sintered sheet obtained as described above had high strength and had no trouble in handling.

The obtained flat plate-shaped sintered sheets having air holes and corrugated sintered sheets were alternately laminated to manufacture an adsorbent (volume 100 cm ³ ) having the shape shown in FIG. Sealed with non-woven fabric. The bulk density of the adsorbent is about 0.39.
It was g / cm ³ .

Air containing 1000 ppm of carbon tetrachloride was flown through the obtained laminated adsorbent at a temperature of 25 ° C. in a direction perpendicular to the sintered sheet. The time to reach the equilibrium adsorption amount is 4
The equilibrium adsorption amount was 49%.

Comparative Example 1 Commercially available coal-based granular activated carbon (specific surface area 1000 m ² / g,
A wire mesh support was filled with 100 g (average particle size of about 1.6 mm) to form a shape similar to that of Example 1, and then carbon tetrachloride-containing air similar to that of Example 1 was supplied in the thickness direction, The treatment was carried out under the same conditions as in 1.

As a result, the time required to reach the equilibrium adsorption amount was 12 minutes, and the equilibrium adsorption amount was 49%.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an outline of an example of a laminated adsorbent according to the present invention, which is composed of a flat sintered sheet and a corrugated sintered sheet.

FIG. 2 is a cross-sectional view showing an outline of an example of a laminated adsorbent according to the present invention, which is composed of a plurality of sintered sheets having protrusions.

FIG. 3 is a plan view showing an example of a flat sintered sheet having air holes and circular protrusions.

FIG. 4 is a plan view showing an example of a sintered sheet having ventilation holes and linear protrusions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flat plate-shaped sintered sheet 3 ... Corrugated sintered sheet 5 ... Vent hole 7 ... Circular protrusion 9 ... Linear protrusion

Claims (3)

[Claims] 1. A laminated adsorbent in which a plurality of sintered sheets of activated carbon are arranged in layers so that voids are formed between the respective sheets, each sintered sheet having a hole for passing a processing gas. A laminated adsorbent characterized in that 2. The laminated adsorbent according to claim 1, wherein voids are formed by alternately laminating corrugated sintered sheets and planar sintered sheets. 3. The laminated adsorbent according to claim 1, wherein protrusions are formed on the sintered sheet as means for forming voids.