JPS5817833A - Production of honeycomb structural body consisting essentially of zeolite for adsorption of moisture in gas - Google Patents

Abstract

PURPOSE:To produce a structural body for adsorption of gases of an outstanding adsorptive property and high strength inexpensively by forming a mixture obtd. by adding a binder and water to zeolite power into a honeycomb shape, a calcining the molding after drying the same if it contains much water. CONSTITUTION:About 95-30wt% synthetic zeolite powder and about 5-70% an inorg. binder are compounded and water is added to the mixture thereof and the mixture is extruded or pressed to a honeycomb shape of required sizes. The amt. of water is preferably about 25-35 parts based on 100pts.wt. the compound in the case of an extrusion molding method and about 4-30 parts in the case of a press molding method. If natural zeolite is used, the lower limit in the content of zeolite is about >=50%. Further it is preferable to compound about 0.5-5 parts. an org. binder such as carboxy methyl cellulose based on 100 parts the total weight of the zeolite and the inorg. binder. If necessary, the molding is dried down to <=10% moisture in an atmosphere of >=80% relative humidity, then it is calcined at about <=800 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a honeycomb structure mainly composed of zeolite for adsorbing moisture in gases, which has particularly excellent adsorption properties, good vibration resistance and abrasion resistance, and is resistant to powdering. The present invention relates to a method for manufacturing a zeolitic honeycomb structure for moisture adsorption at a low cost, which exhibits a number of excellent characteristics such as low heat absorption.

Naturally occurring zeolites or synthetic zeolites have recently come to be widely used as adsorbents, catalyst carriers, and the like. Among these zeolites, synthetic zeolite comes in the form of beads, pellets, powder, and tablets, and natural zeolite comes in crushed sieve products and powder products, and powder products can also be used as paper-making fillers. It is used as an absorbent paper and has even been developed as an absorbent paper.

By the way, among the uses of such zeolite, it is used as an adsorbent for dehydrating Freon gas in automobiles and home air conditioners and refrigerators, and as an adsorbent for removing moisture from the air in air brakes of railway east cars, etc. Heath products are generally used in these applications, but the vibrations that are inevitably applied in these applications cause the bead-shaped zeolite to become powder, clogging the tubules, etc. are doing. Also, since zeolite has a strong adsorption power, it needs to be quickly incorporated into the equipment, but bead-shaped zeolites require a lot of time to fill, and may even reduce the zeolite's original adsorption ability. There it was.

The present invention has been developed with these circumstances in mind, and has excellent adsorption properties, good vibration resistance and abrasion resistance, is difficult to powder, is easy to handle, and can be used as a component. The purpose of this invention is to provide a method for manufacturing a zeolitic honeycomb structure at low cost with good workability.

Therefore, in the present invention, a mixture obtained by uniformly mixing zeolite powder, a predetermined inorganic binder, and water is extruded from an extrusion mold or pressed using a press mold. If the moisture content of the obtained honeycomb molded product exceeds 10% after forming it into a honeycomb shape, it is dried in an atmosphere with a relative humidity of 80% or more until the moisture content becomes 0% or less. A honeycomb structure for adsorbing moisture in gases mainly composed of zeolite, characterized in that it is made into a strong single body by drying in a drying process including It's in the way the body is manufactured.

According to the present invention, the predetermined zeolite raw material is
Extrusion molding can be formed in large quantities as a single honeycomb-shaped structure more easily than using a predetermined mold using a press molding operation, making it much cheaper than traditional bead-shaped products. Moreover, since the honeycomb holes of the honeycomb structure also serve as ventilation holes for the processing gas, there is less pressure loss, which allows the blower capacity to be lowered, which in turn makes it possible to reduce equipment costs. be. In addition, the obtained honeycomb structure is
Because it is a single body with sufficient strength, it has excellent vibration resistance, good wear resistance, and is difficult to powder. Therefore, it is effective against the problem of clogged tubes caused by powdering as in the past. This resulted in the issue being resolved. Furthermore, the honeycomb structure obtained according to the present invention has good workability as a component (adsorbent), is easy to incorporate into equipment, can be assembled in a short time, and has a strong adsorption force. Problems such as exposing zeolite to air and reducing its performance can now be completely avoided.

Note that the zeolite used in the present invention includes:
There are synthetic zeolites such as 4A, 3A, 5A, 18x, and Y types, and natural zeolites such as clinoptilolite and mordenite, and these are generally used as powders with a predetermined particle size suitable for molding.

Further, as the inorganic binder mixed with the zeolite powder, kaolin thread, clays such as sericite type and montmorillonite type, sodium silicate, aluminum phosphate, silica sol, alumina sol, etc. are used.

The blending ratio of these zeolite powders and inorganic binders is, in the case of synthetic zeolite, in the form of water bound in the zeolite crystal structure (crystal water), with respect to 95 to 30% by weight of the synthetic zeolite. , 5-70% by weight of inorganic binder will be used. In addition, if the amount of inorganic binder blended is too small, it will not be possible to form a honeycomb structure with sufficient strength, and if the zeolite charge is too small, the adsorption performance will inevitably be low, and a large amount of inorganic The adsorption force is also inhibited by the binder, making it practically unacceptable. However, when using natural zeolite, it is often a mixture with Viscous-L, so there are cases where there is no need to add a separate inorganic binder, and in such cases, the lower limit of zeolite is Generally, it is considered to be about 50 heavy claw bullets.

In addition, the amount of water added to the zeolite powder and inorganic binder for molding is determined appropriately depending on the molding method employed, but in general, in the press molding method, the amount of water added to the zeolite powder and inorganic binder is Total amount of non-binding agent: It is desirable to mix in a ratio of about 4 to 80 parts by weight per 100 parts by weight, and in the case of extrusion molding, about 25 to 85 parts by weight.

Furthermore, it is desirable to mix a predetermined amount of an organic binder into the homogeneous mixture of zeolite powder, inorganic binder, and water. By blending this organic binder,
The plasticity of the mixture can be improved, the extrudability can be effectively improved, and the organic binder in the molded product is burned out by the sintering operation of the molded product, thereby causing a cavitation phenomenon. Improved air permeability and thus moisture adsorption performance can be achieved. The organic binder includes carboxymethyl cellulose, polyvinyl alcohol, etc., and is generally blended at a ratio of about 0.5 to 5 parts by weight based on the total amount of zeolite powder and inorganic binder = 100 parts by weight. That will happen.

The thus obtained homogeneous mixture containing at least the zeolite powder, inorganic binder, and water is then processed into a large number of molds by an extrusion molding method using a predetermined extrusion mold or a press molding method using a predetermined press mold. The honeycomb structure is formed into a known honeycomb structure in which a large number of circular holes or square holes are formed in the axial direction within a cylindrical or columnar body. Note that the size of the honeycomb holes is generally increased by about 0.5 mm or more in diameter or on one side.

Next, this molded zeolite molded product contains a large amount of water and cannot be used for the intended purpose as it is, so it is preferably subjected to a drying operation, but at that time it is dried rapidly. In this case, the difference in the degree of drying shrinkage in each part may cause adverse effects such as cracks in the molded product. Therefore, in the present invention, the honeycomb is not dried in an atmosphere with relative humidity of 80% or more. Moisture @ (ratio of remaining water excluding crystal water in zeolite. The same applies hereinafter) is 1
If the voice is below 0%, it is necessary to gradually dry it out.

In addition, the temperature for such gradual drying is generally about 30°C to 70°C.

After the gradual drying operation is completed, the honeycomb molded product is further dried in a conventional drying oven at 50 to 60°C, or left indoors, etc. The final drying is then carried out using the usual drying methods. Note that this drying operation is performed for molded products with a moisture content of more than 10%, and in press molding operations where the moisture content is lower than 10%.
Molded articles having a moisture content of less than 10% can also be obtained, and such molded articles may not be subjected to the drying operation.

In addition, for honeycomb molded products that have been subjected to such drying or that have not been subjected to drying operations due to low moisture content, zeolite powder is bound with the inorganic binder contained therein, and the molded product is In order to increase the strength of the product as well as its vibration resistance and abrasion resistance, a firing operation is performed at a temperature not exceeding 800°C, preferably at a temperature of about 500 to 800°C. Moreover, this calcination operation completely removes the crystal water bound and contained within the zeolite crystals, and exhibits its remarkable water adsorption properties. Note that an excessively high firing temperature must be avoided, as this will destroy the crystal structure of the zeolite, which is the base of the honeycomb molded product.

The thus obtained honeycomb molded article according to the present invention, that is, the honeycomb structure, exhibits its remarkable water adsorption performance through the final firing operation, and thus can be used as is for various purposes. That is, as an adsorbent for dehydrating Freon gas, which is used as a refrigerant in automobiles, home air conditioners, and refrigerators, 1. In addition, it is advantageously used as a moisture adsorbent in the air in air brakes for railway vehicles, etc., and as a moisture adsorbent that has an adverse effect on polymerization operations of ethylene, propylene, etc.

Hereinafter, some examples will be shown to clarify the present invention in more detail, but it goes without saying that the present invention is not limited in any way by the description of these examples. In addition, all parts and percentages in the examples are based on weight unless otherwise specified.

Example 1 Synthetic zeolite) 4A type powder SONG (heavy electric after water adsorption.

70 parts (the same applies hereinafter), 29 parts of frog's eye clay, and 1 part of bentonite, add 12 parts of water, mix well in a kneader, and then fill it into a press mold to produce 200 kg/cu.
By press-molding into a honeycomb mold at a pressure of t, a cylindrical honeycomb molded product having an outer diameter of 60 mm, a honeycomb pore diameter of 8111111%, a number of honeycomb holes of ios, and a thickness of 20+ nm was obtained. Next, the obtained molded product was dried in an atmosphere with relative humidity of 90% until the moisture content became 6%, and then left indoors to air dry until the moisture content became 1%. The dried product was calcined at a temperature of 700°C.

The amount of moisture adsorbed per gram of the zeolitic honeycomb (molded product) thus obtained was 16 g of O. In addition, when this honeycomb was installed in a device as a moisture adsorbent for Freon gas in an automobile air conditioner and tested, it showed excellent moisture adsorption performance and almost no pulverization was observed even when the vehicle was vibrated. It was recognized that the material had excellent vibration resistance and wear resistance.

Example 2 Synthetic zeolite) 4A type powder, 42 parts of frog's eye clay, 5 parts of bentonite, 8 parts of silica sol, 0 parts of PVA
．． After uniformly mixing 8 parts and 10 parts of water with a kneader, this was press-molded into a honeycomb mold at a pressure of 200 kg/cot.Outer diameter: 6011111% Honeycomb pore diameter;
A honeycomb molded product having a honeycomb hole count of 7 and a thickness of ±25+nm was obtained. Next, this obtained molded product is
After drying in the same manner as in Example 1, at 700°C.
As a result of firing, an extremely hard honeycomb molded product (structure) was obtained.

The amount of moisture adsorbed per gram of the zeolite honeycomb thus obtained was 0.11 g, and the product was found to have excellent vibration resistance and abrasion resistance, and was difficult to powder.

Example 3 80 parts of water was added to 80 parts of synthetic zeolite 4A type powder, 14 parts of frog's eye clay, 2 parts of bentonite, and 4 parts of silica soda, and the mixture was thoroughly kneaded in a kneader and then kneaded in a vacuum clay kneader. By extrusion molding using an extrusion method using a honeycomb mold, a rectangular hole with an outer diameter of 80111 ms and a side i of 811
1m N wall thickness; 1aIIns height and length); 1oOao
An np honeycomb molded product was obtained. Next, the obtained molded product is dried in an atmosphere with a relative humidity of 95% until the moisture content is 4%, and then further dried indoors (normal conditions) until the moisture content is 1% or less. Then, as a result of firing at 700℃, the amount of water adsorption per gram of honeycomb was -0,
A no-nikum structure with excellent properties weighing 18 g was obtained.

Example 4 In Example 3, when kneading with a kneader, Clul
As a result of further blending 2 parts of O, a honeycomb with a smoother surface than the honeycomb obtained in Example 3 was obtained. Well, the amount of moisture adsorbed per gram of nicum was o, t s g.

Example 5 Synthetic zeolite) 65 parts of aA type powder, 25 parts of frog's eye clay,
1 part of C, MC for 8 parts of this clay and 2 parts of bentonite
After adding 30 parts of water and 30 parts of water and kneading well in a kneader, the honeycomb was extruded using a vacuum kneader and a honeycomb mold to obtain a honeycomb having the same shape as in Example 8. After drying in an atmosphere with relative humidity of 95% until the moisture content was 4%, it was further naturally dried indoors until the moisture content was 1% or less, and then fired at 660°C.
A honeycomb structure with a water adsorption amount of 0.14 g per gram of honeycomb was obtained.

Applicant: Kyoritsu Ceramic Materials Co., Ltd. Same as Misato Pottery Co., Ltd.

Claims (2)

[Claims] (1) A mixture of zeolite powder, a predetermined amount of an inorganic binder, and water is uniformly mixed into a honeycomb shape by extruding it from an extrusion mold or pressing it with a press mold. After molding, if the moisture content of the obtained honeycomb molded product exceeds 10%, it is dried in an atmosphere with a relative humidity of 80% or more (including a step of drying in air until the moisture content becomes 10% or less). Dry in the drying process, then at 800℃
A method for producing a honeycomb structure for adsorbing moisture in a gas, which is mainly composed of zeolite, which is made into a strong single body by firing at a temperature not exceeding . (2) The manufacturing method according to claim 1, characterized in that a predetermined amount of a binder is uniformly blended into the mixture consisting of the zeolite powder, an inorganic binder, and water. .