JP2627466B2 - Adsorbable honeycomb-shaped ceramic body and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorptive honeycomb-like ceramic body and a method for producing the same. More specifically, an adsorptive honeycomb-shaped ceramic preferably used as a desiccant for generating dry air for drying powders in a microwave drying device or the like for heating and drying powders using microwave heating. The present invention relates to a body and a method for producing the same.

[0002]

2. Description of the Related Art An apparatus using hot air has been used to dry powders containing water or a low boiling point solvent.
In such a device, from 50 to 10 from the viewpoint of effective use of heat.
Air having a relatively high temperature of about 0 ° C. is circulated and used. In order to generate such dry air, a desiccant having a high water adsorption capacity in the above temperature range is desired.

[0003] As a method of generating dry air, there are a granule type in which a granular desiccant is used and the air is circulated while rotating a packed bed containing the same, and a cylindrical dry form specially processed into a honeycomb shape. It is roughly classified into a honeycomb rotor system in which air is circulated to obtain dehumidified air while rotating the agent at a slow speed of about 3 to 10 times per hour. In the honeycomb rotor system, air flowing through a cylindrical honeycomb rotor (desiccant) is dried, and heated air (hot air) for heating and dehumidifying and drying the absorbed desiccant is regenerated by heating and dehumidifying. The desiccant is separated into cooling air for cooling, and the air is dehumidified, and the desiccant is regenerated and cooled sequentially and continuously by rotating the rotor through a circulation zone of the separated air. It is easy to regenerate the desiccant, and has a characteristic that stable dry air without unevenness of dehumidification can be obtained.

Although silica gel and zeolite are well known as desiccants used in these dryers, silica gel has good water adsorption capacity at low temperatures, but has insufficient water adsorption capacity at relatively high temperatures as described above. It is. Even if the temperature of the dry air generator is lowered to improve the moisture adsorption characteristics of silica gel, cooling with water in summer is limited to a cooling temperature of about 35 ° C., but at such a temperature, the silica gel is still cooled. Adsorption properties are inadequate. Therefore, silica gel is not satisfactory as a desiccant for a drying apparatus using microwave heating.

On the other hand, zeolite (molecular sieve)
Is useful as a desiccant because of its excellent ability to adsorb moisture at relatively high temperatures as described above. However, zeolite is usually used in granular form because of the problem of workability, and the surface area as a desiccant is not always sufficient,
It is desired to increase the adsorption surface area and improve the dehumidification ability.

[0006] As a desiccant which has improved the adsorption surface area of zeolite, a desiccant obtained by coating a structure in which a ceramic sheet is formed into a honeycomb shape with zeolite powder is known, and is used as a honeycomb rotor. However, this desiccant has the special property of processing the ceramic sheet into a corrugated sheet by special processing such as corrugating, and then adsorbing the zeolite powder on the surface of the honeycomb structure where the ceramic sheet is wound in a cylindrical shape and fixing it. However, there are drawbacks that the production is difficult and the cost is high.
Further, in a dryer using a honeycomb rotor, 200 to 25 is used.
Since the regeneration of the desiccant with hot air at about 0 ° C. and the cooling of the regenerated desiccant with air at about room temperature are repeatedly performed,
There has been a problem that the zeolite adhered to the surface of the ceramic sheet falls off due to thermal shock or the like, or is powdered, thereby lowering the durability as a desiccant.

In addition to the desiccant, a ceramic porous body having a honeycomb structure of an extruded product, a three-dimensional network structure, or a swirling laminated structure of a linear extruded product is known as a honeycomb ceramic body. (Japanese Unexamined Patent Publication No. 63-2
No. 42980), this molded article is used as a filter or a catalyst carrier for a molten metal, and a drying agent formed by extruding a composition containing zeolite powder into a honeycomb shape is not known.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to utilize the excellent moisture adsorption properties of zeolite, to have excellent dehumidifying ability at a relatively high temperature, and to repeatedly use regeneration and cooling by heating. An object of the present invention is to provide a desiccant excellent in durability at the time and a method for producing the same.

[0009]

That is, the present invention provides:
(1) an adsorptive honeycomb-shaped ceramic body obtained by extruding a composition containing zeolite powder having moisture adsorption properties, inorganic fibers, and an inorganic binder into a honeycomb shape and firing the composition;
(2) the adsorptive honeycomb-shaped ceramic body of (1), wherein the inorganic fibers are sepiolite fibers, and the inorganic binder is colloidal silica; and (3) the zeolite powder having moisture adsorption properties, the inorganic fibers, and the inorganic binder. The composition was extruded into a honeycomb shape, and the extruded product was dried.
Baking at a temperature of 0 to 700 ° C. for at least 1 hour;
(4) The method according to the above item 4, wherein the inorganic fibers are sepiolite fibers, and the inorganic binder is colloidal silica.

[0010]

The present invention provides an adsorptive honeycomb-shaped ceramic body obtained by extruding a composition containing a zeolite powder having moisture adsorption properties as an essential component into a honeycomb shape and firing it, and a method for producing the same. Is obtained by extruding a zeolite powder having excellent moisture adsorption characteristics at a relatively high temperature of 50 to 100 ° C. into a honeycomb structure having a large surface area, thereby achieving excellent desorption at these temperatures. Demonstrate the ability to wet.
Further, according to the method of the present invention, it is possible to easily and inexpensively manufacture an adsorptive honeycomb-shaped ceramic body having such a dehumidifying ability and easy to be installed in a drying device or the like.

In the present invention, zeolite can be used as a natural or synthetic product, and commercially available products such as molecular sieves and various compositions widely used in the field of petrochemicals can be used without particular limitation. In the present invention, such a zeolite is used as a powder having an average particle size of about 0.3 to 5 μm.

[0012] The zeolite-containing composition used in the present invention contains inorganic fibers as a support material for the zeolite to impart an appropriate strength to the molded product. Ceramic fibers such as sepiolite fiber, glass fiber, alumina fiber, alumina / silica fiber, and silica fiber are used as the inorganic fiber, and among these, sepiolite fiber is preferably used. 0.001 to 2 mm as the fiber length of inorganic fiber
It is appropriate that the fiber diameter is about 0.01 to 1 μm.

Further, the composition contains an inorganic binder to impart appropriate moldability to the composition, and through this, the zeolite powder and the inorganic fibers are appropriately dispersed and held in the molded article. . As the inorganic binder, colloidal silica, alumina sol, ethyl silicate, silica sol,
Zirconia sol and the like are used, and among these, colloidal silica is preferably used. The content of each of these components is preferably about 30 to 87% by weight of zeolite, 10 to 30% by weight of inorganic fiber, and about 3 to 10% by weight of inorganic binder in terms of solid content. In addition, organic binders such as polyvinyl alcohol (PVA), sulfonyl methyl chloride (SMC), methylcellulose (MC), carboxymethylcellulose (CMC), and starch may be used as other components, if desired. This organic binder is decomposed and removed in a firing step described later.

The method of the present invention for producing the above-mentioned adsorptive honeycomb-shaped ceramic body comprises preparing a composition containing each of the above-mentioned components, extruding the composition, drying the molded product, and drying the composition. Baking at a temperature of 400 to 700 ° C. for at least 1 hour. The method of the present invention basically consists of a simple operation of extrusion molding and firing, and is characterized by the fact that the process is extremely simple and can be performed at low cost as compared with a conventional desiccant in which zeolite powder is fixed to a ceramic sheet. Having.

The composition used in the present invention contains an inorganic fiber such as zeolite powder and sepiolite and an inorganic binder such as colloidal silica. To obtain a good extrudate, water and optionally polyvinyl alcohol are used. And other organic binders can be added as appropriate.

In the present invention, the extrusion molding method of the composition is not particularly limited, and an extrusion die (die) having a required shape is used.
Using an extruder having the above, put the composition into this,
A molded product can be obtained by extruding at a speed of preferably about 20 to 200 cm / min.

The drying is carried out by natural drying at room temperature for about 24 hours, but it may be dried by slightly heating to about 40 to 80 ° C. by a microwave heating device or the like.

The calcination is carried out at a temperature of 400 to 700 ° C., preferably 500 to 600 ° C., which does not impair the adsorption characteristics of the zeolite.
For at least one hour. The adsorptive honeycomb-like ceramic body thus obtained has a structure in which zeolite powder and inorganic fibers are appropriately dispersed and held via an inorganic binder, and improves the adsorption surface area of zeolite,
The excellent moisture adsorption property is sufficiently exhibited.

In the present invention, the shape and size of the adsorptive honeycomb-shaped ceramic body can be appropriately selected depending on the method of use as a desiccant and the like. In the present specification, the term “honeycomb” refers to a so-called hole-shaped honeycomb nest (6).
Not only a square shape but also a square shape, a triangle shape, other polygonal shapes or a circular shape. FIG. 1 shows an example of a desiccant for a honeycomb rotor. That is, in this example, the columnar adsorptive honeycomb-shaped ceramic body 1 which is a desiccant has a granular honeycomb structure formed by a plurality of holes 2 having a rectangular cross section penetrating along the extrusion direction of the column. And has a structure in which air can freely flow through the hole 2. This desiccant is mounted as a honeycomb rotor of the above-mentioned microwave dryer through the shaft hole 3 in the center, and is repeatedly used by dehumidification → regeneration → cooling. The shape and size of the hole 2 provided in the ceramic body 1 can be appropriately selected. In this example, the center interval between the holes 2 is about 2 mm, and the thickness of the partition walls 4 forming the holes 2 is about 0.5 mm, but it is a matter of course that the present invention is not limited to this. In FIG. 1, the hole 2 is shown in an enlarged manner to simplify the description.

[0020]

The present invention will be described below in further detail with reference to examples.

Example 1 The adsorbable honeycomb-shaped ceramic body 1 (diameter 5 cm, height 10 cm) illustrated in FIG. 1 was produced as follows. First, 64 parts by weight of zeolite powder, sepiolite fiber (commercially available, manufactured by Mizusawa Chemical Co., Ltd., diameter 0.01 μm, fiber length 3 μm) 2
A composition comprising 1 part by weight and 15 parts by weight of colloidal silica (solid content: about 10%) was prepared. The zeolite powder has a composition known as Silton B (manufactured by Mizusawa Chemical Co., Ltd.) [Na ₂ O: SiO ₂ : Al ₂ O ₃ = 1: 2:
1 (molar ratio)] was used after pulverizing to an average particle size of 0.6 μm.

Next, the composition (10 kg) is supplied to an extruder having an extrusion die having an extruded shape formed into a cylindrical gourd structure having a plurality of holes 2 as shown in FIG. Extrusion was performed at an extrusion speed of 50 cm / min. This molded product was naturally dried at room temperature for about 24 hours. Next, the molded product was allowed to stand in a firing furnace (electric furnace), then heated to 500 ° C. at a rate of 2 ° C./min, and fired at this temperature for 1 hour. Thereafter, the power supply to the firing furnace was stopped, and the molded product was cooled to room temperature while being left in the furnace, thereby obtaining the adsorptive honeycomb-shaped ceramic body 1 of the present invention as illustrated in FIG. In this ceramic body, zeolite powder and sepiolite fibers were uniformly dispersed and held in colloidal silica.

This ceramic body is used as a honeycomb rotor of a microwave dryer and has an absolute humidity of 0.010 to 0.015.
When dehumidification of kg / kg of air was performed continuously for 12 hours, dry air having a dehumidification rate of 70 to 90% was obtained stably. The conditions for using the rotor at this time are as follows. Drying air temperature: 40 to 50 ° C, heating / regenerating air temperature: 230 to 250 ° C, cooling air temperature: 40 to 50 ° C, Rotor rotation speed: 3 rotations / hour.

Further, this ceramic body is used continuously for about 12 hours a day, and after the use for 700 days, the zeolite does not fall off or powder like a conventional honeycomb rotor having zeolite powder fixed thereon. There was no decrease in dehumidification capacity.

Example 2 An adsorptive honeycomb ceramic body of the present invention was obtained in the same manner as in Example 1 except that the firing temperature of the extruded product was 600 ° C. This ceramic body also exhibited the same excellent dehumidifying ability as in Example 1.

[0026]

As described above, according to the present invention, 50
It has become possible to provide an adsorptive honeycomb-shaped ceramic body having an excellent dehumidifying ability at a relatively high temperature of １００100 ° C. Further, according to the method of the present invention, a desiccant that exhibits excellent dehumidifying ability at such a temperature and is extruded into a honeycomb structure, which is a structure having a large surface area, is used by repeatedly heating and regenerating and cooling. As a result, it has become possible to provide easily and inexpensively those having excellent durability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of an adsorptive honeycomb ceramic body according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Adsorbable honeycomb-shaped ceramic body 2 Hole part 3 Shaft hole 4 Partition wall

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiko Sukeda 4-13-4, Asakuraminami, Takarazuka-shi, Hyogo Prefecture Fragrance Takarazuka 105 (72) Inventor, Yasuyoshi Kenji 3-11, Obukicho, Takarazuka-shi, Hyogo Marumi-en 203 (56) References JP-A-63-264125 (JP, A) JP-A-61-242911 (JP, A) JP-A-1-286958 (JP, A) JP-A-57-160949 (JP) , A) JP-A-56-165097 (JP, A)

Claims (2)

(57) [Claims] 1. A zeolite powder having moisture adsorption properties ,
An adsorptive honeycomb-shaped ceramic body obtained by extruding a composition containing sepiolite fibers and colloidal silica into a honeycomb shape and firing the composition. 2. A zeolite powder having moisture adsorption properties ,
An adsorptive honeycomb-shaped ceramic body, comprising: extruding a composition containing sepiolite fiber and colloidal silica into a honeycomb shape; drying the extruded product; and firing at 400 to 700 ° C. for at least 1 hour. Manufacturing method.