JPH0656404A - Preparation of adsorbent for oxygen generator - Google Patents

Abstract

PURPOSE: To provide an inexpensive adsorbent fox oxygen generator capable of separating oxygen with high efficiency by using a natural zeolite and treating with a chemical and by activation with a simple process.

CONSTITUTION: The natural zeolite is pulverized and after that, a pretreating step for treating with a strong acid (BCl or B₂SO₄), washing and drying, a chemically treating step for ion exchanging with calcium chloride (CaCl₂) and an activating step for activating by heating and firing at ≤650°C are performed and after an inorganic binder is added to mold, the molding is fired again at ≤650°C to be activated.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent applied to an oxygen generator, and more specifically, a natural zeolite (zeolite) is used in place of an expensive adsorbent for oxygen separation, and a chemical by a simple process is used. And by the activation process,
The present invention relates to a method for producing an inexpensive adsorbent for an oxygen generator suitable for separating oxygen with high efficiency.

[0002]

2. Description of the Related Art FIG. 1 shows an oxygen generation process in an oxygen generator for air conditioning or medical use by a pressure difference adsorption method (PSA method), and FIG. 2 shows a method for separating air in an adsorption tower of FIG. The state in which the adsorbent is filled is shown. As shown in FIGS. 1 and 2, the compressed air that has entered through the air compressor 1 is transferred to the solenoid valve 4a.
And 4b, they are introduced into the adsorption towers 3 and 3'which are filled with the desiccant 8 and the synthetic zeolite 7 which is the adsorbent for air separation. Here, oxygen and carbon dioxide in the air are adsorbed by the synthetic zeolite 7, and oxygen is supplied to the solenoid valve 5a,
By the operations of 5b and 5c, they pass through the buffer tank 6 in the direction of arrow B and are separated.

On the other hand, in order to remove the nitrogen and carbon dioxide remaining in the synthetic zeolite 7 and regenerate the synthetic zeolite, the pressure inside the adsorption towers 3 and 3'is reduced by the vacuum pump 2 operated by the solenoid valves 4c and 4d. Then, nitrogen and carbon dioxide are pulled out in the direction of arrow C.

A conventional method for producing a synthetic zeolite used in such an oxygen generator will be described below with reference to FIG. The manufacturing process shown in FIG. 3 (Japan, adsorption engineering,
Page 126, 1977) was started by Linde for industrial use at the end of 1954, using Barrer's research results in the 1940s as a mother body. (II) and commercialization stage (III).

In the raw material mixing step (I), bauxite, which is a raw material for the synthetic zeolite material, sodium hydroxide, sodium silicate, and aluminate are mixed and reacted to obtain a gel zeolite. In the granulation step (II), the zeolite gel obtained in the above step is dried to obtain a crystallized zeolite.

The reaction process that has undergone such steps is represented as follows. NaOH (a) + NaAl (OH) ₄ (a) + Na ₂ SiO ₃ (a): mixing stage ↓ temperature [Na (AlO ₂ ) (SiO ₂ ), NaOH, H ₂ O]: gel state ↓ temperature (dry) Na [(AlO ₂ ) (SiO ₂ ), H ₂ O]: Zeolite Crystal (where a represents an aqueous solution) The zeolite in the crystallized state thus obtained is necessary in the (III) stage. Depending on the condition, the product is fired to be manufactured into a specific form, or crushed and classified to be manufactured into a product.

[0007]

However, in such a conventional production method, in order to obtain a desired specific synthetic zeolite material, raw materials of various components are mixed to crystallize the synthetic zeolite by mutual reaction. Since it should be achieved, it is difficult to adjust various conditions such as the mixing composition ratio of various raw materials, reaction temperature and time, and the process for each step treatment must be complicated and the equipment capacity must be increased. There was a problem such as.

The present invention has been made in view of such conventional problems, and oxygen generation capable of separating oxygen with high efficiency can be achieved by using natural zeolite by a simple chemical process and activation treatment. It is an object of the invention to provide an inexpensive adsorbent for dexterity.

[0009]

In order to achieve the above object, the present invention is directed to crushing a natural zeolite, then
Or H ₂ SO ₄ ) treatment, washing with water, and drying, a pretreatment stage, a chemical treatment stage of ion-exchange treatment with calcium chloride (CaCl ₂ ), and an inorganic binder are added and molded,
It again comprises a production step of activating by firing at 650 ° C or lower.

The present invention will be described in detail below. The present invention shows that after crushing natural zeolite, strong acid (HCl or H
₂ SO ₄ ) to remove impurities, wash with water,
Pretreatment stage (I) to dry and calcium chloride (CaC
l ₂ ), a chemical treatment step (II) of ion exchange treatment, an activation step (III) of activating after washing with water and drying, and adding an inorganic binder to form a desired shape, followed by heating to 650 ° C. or lower. The product stage (IV) is activated.

FIG. 4 shows a manufacturing process of the present invention, and the present invention will be specifically described based on the manufacturing process. The manufacturing method of the present invention is divided into four stages. In the pretreatment stage (I), after pulverizing the zeolite produced as a natural mineral state,
An aqueous solution of a strong acid such as hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ) is used at room temperature or at high temperature to remove impurities present in the zeolite. The removal of such impurities is to facilitate the chemical treatment in the subsequent chemical treatment stages. After acid treatment in this way, it is washed with water and dried.

In the chemical treatment step (II), a part or all of the ion-exchangeable sodium ions (Na ⁺ ) in the natural zeolite are converted into calcium ions (Ca ²⁺ ) by using an aqueous solution of calcium chloride (CaCl ₂ ). Replace. The reason why the pretreatment step (I) and the chemical treatment step (II) are carried out in this way is that the natural zeolite has a non-uniform quality and contains impurities, so that the pressure difference adsorption method (PSA method) is used as it is in the natural state. Since it is not suitable to be used as an adsorbent for oxygen separation according to (4) above, the above-mentioned steps are performed.

That is, zeolite has the general formula (M ¹ , M
¹¹ _1/2) is a general term for _{(Al m Si n O 2 (} m + n) hydrous alumina silicates represented by · H ₂ O. Here, M
¹ (monovalent metal ion) represents sodium (Na ⁺ ), lithium (Li ⁺ ), potassium (K ⁺ ), etc., and M ¹¹ (2
The valent metal ion) represents calcium (Ca ²⁺ ), barium (Ba ²⁺ ), strontium (Sr ²⁺ ), and the like. Among natural zeolites, M ¹ and M ¹¹ are mainly sodium (N
a ⁺ ) and calcium (Ca ²⁺ ). Where m,
n is a coefficient.

Therefore, in order to use the natural zeolite as an adsorbent for oxygen separation by the pressure difference adsorption method, all or part of sodium ion (Na ⁺ ) which is a monovalent metal ion in the natural zeolite is converted into calcium ion ( C
a ²⁺ ), it is possible to carry out the chemical treatment step (II) after the pretreatment step (I) as described above.
Thus, an ion-exchanged zeolite will be obtained by using an aqueous solution of calcium chloride (CaCl ₂ ).

Next, in the activation step (III), the ion-exchanged zeolite is washed with water to remove chlorine ions (Cl ⁻ ) in the excess chemical and dried, and then the temperature is lowered to 650 ° C. or lower, which is a thermal decomposition temperature range. Activated by heating and firing. In the commercialization stage (IV), the activated zeolite is added with kaolin, which is an inorganic binder, in an amount of 5 to 20% by weight of the zeolite, wet-mixed, molded into a specific shape, and then heated and calcined at 650 ° C. or lower. The present invention is completed by activating by activation.

[0016]

EXAMPLES The present invention will be described more specifically below based on examples. As a natural zeolite, a model night (MORDENITE) type zeolite was pulverized to about 50 mesh and treated with hydrochloric acid (HCl) in the pretreatment step (I) to remove impurities in the natural zeolite. At this time, since the zeolite has a large acid resistance, the structural destruction of the zeolite itself does not occur even if the acidity is increased, but it is preferable to treat the zeolite with hydrochloric acid at a concentration of 1 to 3 at room temperature.

After the acid treatment is finished, it is washed with water and dried, and in the chemical treatment step (II), 0.2 to 2 molar concentration of calcium chloride (CaCl ₂ ) is added and the mixture is treated at 60 to 80 ° C. for 5 to 6 hours. By stirring, ion-exchanged modified zeolite was obtained.
The ion exchange process in the chemical treatment stage (II) can be repeated once or several times.

Then, in the activation step (III), the ion-exchanged zeolite is washed with water to remove chlorine ions, and
After being dried at 00 ° C., it was heated and baked at 650 ° C. or lower to be activated. Then, in the commercialization stage (IV), kaolin, which is an inorganic binder, was added in an amount of 5 to 20% of the weight of the zeolite, and the mixture was molded and then fired again at 650 ° C. or lower for activation.

In order to evaluate the performance of the adsorbent obtained by the above-mentioned method, B. E. 20 ℃, 760mmHg by T method
In this state, the adsorption amounts of nitrogen (N ₂ ) and oxygen (O ₂ ) were measured. The results are shown in Table 1.

[0020]

[Table 1]

As can be seen from Table 1, in the present invention, the adsorption ratio (N ₂ / O ₂ ) was increased as compared with the starting material of Comparative Example A (mordenite type zeolite), and Comparative Example B which was commercially available.
(MS, a synthetic zeolite manufactured by Union Carbide
The adsorption capacities of N ₂ and O _{2 in} Z-5A) are each 1
Even when compared with the cases of 0.9 and 3.2 (N ₂ / O ₂ = 3.4), the adsorption ratios of about the same level were obtained.

The size of the adsorption tower is 5.4 cm (φ) × 1
Measurement was carried out to evaluate the oxygen separation concentration performance by using a two-column oxygen generator by a pressure difference adsorption method composed of 5 cm (L), pressure 3 kg / cm ² , and switching time 20 seconds.
The result as shown in FIG. 5 was obtained. As shown in FIG. 5, the present invention is superior in oxygen separation performance to Comparative Example A (mordenite-based zeolite as a starting material), and Comparative Example B
Compared with (MSZ-5A manufactured by Union Carbide Co., Ltd.), a performance of approximately the same level appeared. Here, what is indicated by a dotted line represents a steady oxygen concentration (20.9%).

[0023]

INDUSTRIAL APPLICABILITY As described above, the adsorbent of the present invention used in the oxygen generator is obtained by subjecting natural zeolato to chemical treatment and activation treatment in a simple production process, and is not a conventional synthetic zeolite adsorbent. In comparison, it is cheaper, has better performance, and can be manufactured with small-scale equipment. Further, it can be widely applied to air purifiers, air conditioner oxygen generators for air conditioners, medical oxygen generators, and the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an oxygen generation process in an oxygen generator.

2 is a cross-sectional view of the adsorption tower of FIG.

FIG. 3 is a manufacturing process of a conventional adsorbent.

FIG. 4 is a manufacturing process of the adsorbent of the present invention.

FIG. 5 is a graph showing oxygen separation performance.

[Explanation of symbols]

1 Air Compressor 2 Vacuum Pump 3, 3'Adsorption Tower 4a, 4b, 4c, 4d, 5a, 5b, 5c Solenoid Valve 6 Buffer Tank 7 Synthetic Zeolite 8 Desiccant

Claims (8)

[Claims] 1. A pretreatment step of (I) crushing natural zeolite as a starting material, followed by strong acid treatment, washing with water, and drying, (II) chemical treatment step of ion treatment with calcium chloride (CaCl ₂ ), (III) It is characterized by comprising an activating step of activating by heating and baking after washing with water, and (IV) a commercializing step of activating by burning again after forming by adding an inorganic binder. A method for producing an adsorbent for an oxygen generator. 2. The natural zeolite is mordenite (MORD
The method for producing an adsorbent for an oxygen generator according to claim 1, wherein the adsorbent is an ENITE) type zeolite. 3. The strong acid used in the pretreatment step (I) is H 2
The method for producing an adsorbent for an oxygen generator according to claim 1, wherein Cl or H ₂ SO ₄ is used. 4. The method for producing a respiratory agent for an oxygen generator according to claim 3, wherein the strong acid has a concentration of 1 to 3 molar. 5. The calcium chloride (CaCl ₂ ) is less than 0.1.
The method for producing an adsorbent for an oxygen generator according to claim 1, wherein the concentration is 2 to 2 molar. 6. The method for producing an adsorbent for an oxygen generator according to claim 1, wherein 5 to 20% by weight of the zeolite of the inorganic binder is added to the zeolite that has undergone the activation step (III). 7. The method for producing an adsorbent for an oxygen generator according to claim 1, wherein the inorganic binder is kaolin. 8. The activation step (III) and the commercialization step (I)
The method for producing an adsorbent for an oxygen generator according to claim 1, wherein the firing in V) is performed by heating at 650 ° C or lower.