JPS59230637A - Preparation of molecular sieve carbon material - Google Patents

Abstract

PURPOSE:To prepare a molecular sieve carbon material excellent in adsorptive separation capacity, by such a simple preparation method that a predetermined amount of a suitable sticky agent is compounded to fine powdery carbide obtained from non-caking coal while the obtained compound is well mixed to form a granulated substance which is then subjected to heat treatment under a suitable condition. CONSTITUTION:20-30wt% of an org. substance, which shows stickness at a room temp., is soluble in water at a room tem. and further has thermosetting property, such as an aqueous phenol resin solution or a starch size is compounded to fine powdery carbide obtained by carbonizing non-caking coal at 550- 800 deg.C while the obtained compound is granulated to form a granule with a particle size of 1-3mm.phi and this granule is heated at 160-270 deg.C for 1-4 hr. By this method, a molecular sieve carbon material excellent in adsorbing capacity and separation capacity and having high strength can be inexpensively and easily prepared.

Description

[Detailed description of the invention] The present invention relates to a method for producing a molecular sieve carbon material.

Conventionally, as a method for producing molecular sieve carbon materials, A. A method in which activated carbon is impregnated with a resin solution and then carbonized at a temperature of 500 to 850C (Walker, et al: 2nd
Conf, On Ind, Carbon & Qr
aphite 7 (1966)), B, Polymerization Madah/
and a method of adsorbing raw materials to produce phenolic resins or furan resins on activated carbon, polymerizing and/or condensing them, and then heat-treating them at a temperature of 400 to 1000 C (Japanese Patent Publication No. 37036/1983), C1 After molding coal or wood-based carbide by mixing natural rubber, synthetic rubber, thermoplastic resin, etc.,
Carbonization is performed at a temperature of 1400C, and in some cases, the carbonization product is converted into water vapor and carbon dioxide.

600-1000 using a mixture of water vapor and carbon dioxide
C, a method of activating at a temperature (JP-A-53-1195); D, a method of granulating and carbonizing fine powdered coking coal, and then activating it at a temperature of 650 to 800 C while passing a very small amount of water vapor. (Japanese Unexamined Patent Publication No. 55-71615), E1 coal and woody carbide were heated to 200 to 3
A method of impregnating an organic compound with a boiling point of 60C (
(Japanese Unexamined Patent Publication No. 4'1-106982), F, carbide or activated carbon is heated and treated with gas containing methane, benzene, etc., and carbon produced by thermal decomposition of hydrocarbons is deposited on the pore walls. Methods of reducing pore size (S, V
, Moore, et al: Carbon,
15° 177 (1977)), G, and a method of heat-treating activated carbon at high temperatures (Japanese Patent Publication No. 18555/1983).

In the above methods, both A and B involve treating activated carbon with a resin, and G involves heat treating activated carbon at high temperatures, which both involve reprocessing the activated carbon, leading to a rise in production costs. Since C involves the step of mixing a thermoplastic compound with a carbide, molding it, and then carbonizing it, it tends to cause expansion of the molded product, mutual fusion of the molded products, and formation of lumps.

, D is a method of activating carbide, so it is extremely difficult to adjust the pore diameter, leading to a rise in production costs. Since E is a method in which carbide is impregnated with an organic compound having a boiling point within a specific range, the adsorption capacity is inevitably lower than that of the carbide used as the raw material.

F is a method in which carbon produced by thermal decomposition of hydrocarbons is deposited on the pore walls of carbide or activated carbon, so in order to reduce the pore diameter without reducing the pore volume of the raw material, it is necessary to adjust the reaction temperature and the pore walls. It is extremely difficult to control the amount of vapor deposited on the surface.

Focusing on these drawbacks, the present invention has developed a process in which a predetermined amount of a suitable binder is blended into a finely powdered carbide obtained from non-adhesive carbon, the mixture is thoroughly mixed and granulated, and then the mixture is granulated under suitable conditions. The present inventors have invented a method for producing a molecular sieve carbon material that has excellent adsorption and separation ability by heat treatment, is simple to produce, and can be easily provided at low cost.

That is, the specific configuration of the present invention uses non-caking coal of 550 to 80
For the fine powder-like carbide carbonized at a temperature of 0C, an organic substance that exhibits adhesiveness at room temperature, is water-soluble at room temperature, and has thermosetting properties, such as an aqueous phenol resin solution or starch paste, is used as a binder. It is characterized in that after blending 20 to 30% by weight and granulating it, it is heated at a temperature of 160 to 270 tZ' for 1 to 4 hours.

Next, to explain the present invention in detail, the carbide obtained by carbonizing non-caking coal (lignite, lignite) at a temperature of 550 to 800C is finely pulverized to 100 meshes or less, and a phenol resin solution, 2 starch pastes each as a binder
Blend 0 to 30% by weight at room temperature, mix well, and then use a granulator to adjust the particle size to 1 to 2 or 2 to 3 tram.
After granulation at room temperature to nφ, 160 to 2
Heat treatment is performed at a temperature of 70C in an inert atmosphere for 1 to 4 hours.

At temperatures below the carbonization temperature of non-caking coal of 550C, the pore walls of the resulting carbide become clogged with tar substances and the pore volume decreases, resulting in a decrease in adsorption capacity. If the carbonization temperature is high, special consideration must be given to the material of the carbonization device, which is also disadvantageous in terms of thermal energy consumption.

If the amount of the binder added is 20% by weight or more, the strength of the granulated product cannot be said to be sufficient. Furthermore, if the content is 30% by weight or more, the granules tend to adhere to each other and form clumps.

If the temperature is below the carbonization temperature of 160C, the thermal curing of the granules cannot be said to be sufficient. Furthermore, at temperatures above 270C, there is a tendency for the micropore diameter of the granules to increase due to thermal curing and thermal decomposition. Heat curing is insufficient if the heat treatment time is less than 1 hour, and no improvement in quality is observed even if the heat treatment time is 4 hours or more.

Examples of the present invention will be shown below.

Example 1 A carbide obtained by carbonizing lignite at 5500 for 2 hours was finely pulverized to 100 mesh or less. 77% by weight and 23% by weight of starch paste were blended, mixed well, and made into particles with a particle size of 2 to 3 using an extrusion molding machine.
Bφ was granulated. After drying this granulated product at a temperature of 110C for 2 hours, it was heat-treated in a heating furnace at a temperature of 160C in a nitrogen atmosphere for 4 hours. The product was obtained with a yield of 93% based on the dried granules.

The adsorption properties of this product are carbon dioxide, ethane, n-butane, and inbutane (minimum molecular diameters are 3.3A and 4.5A, respectively).
The adsorption isotherm at 25C was determined using a 4.3-hole, 5.0-sized tube, and is shown in FIG.

Examining this figure, it adsorbs carbon dioxide, but hardly any other gases. Molecular diameter 4. This indicates that OX and gases having a molecular diameter larger than that are not adsorbed.

Therefore, the pore diameter is estimated to be approximately 3.3k.

The hardness of this product was 2.0 K9 (Kiya type hardness tester).

Example 2 80% by weight of a product pulverized to 100 meshes or less and 20% by weight of an aqueous phenol solution were blended at room temperature, mixed well, and granulated into particles having a particle size of 2 to 3 mmφ at room temperature using an extruder. This granulated product was dried at a temperature of 110C for 2 hours, and then heat-treated in a heating furnace at a temperature of 200C for 4 hours in a nitrogen gas atmosphere. 90 for dry granules
．． The product was obtained with a yield of 1%.

The results of determining the adsorption isotherm using the same method as in Example 1 were used in the second example.
As shown in the figure, when examining this figure, it can be seen that carbon dioxide is adsorbed to a considerable extent, but ethane, normal butane, and isobutane are hardly adsorbed. Therefore, it is estimated that most of the pore diameters of this product are approximately 3.3A. The hardness of this product was 2.0 K9 (Kiya type hardness tester).

Example 3 Carbide obtained by carbonizing lignite at a temperature of 700C for 2 hours was
A mixture of 70% by weight and 30% by weight of an aqueous solution of East phenol resin pulverized to 0.00 mesh or less was blended at room temperature, mixed thoroughly, and granulated into particles having a particle size of 2 to 3 mmφ at room temperature using an extruder. After drying the granulated material at a temperature of 110C for 2 hours, it was heat-treated in a heating furnace at a temperature of 230C for 4 hours under a nitrogen atmosphere. , with a yield of 80.4% based on the dried granules.

The results of determining the adsorption isotherm using the same method as in Example 1 are shown in the third example.
Shown in the figure. Examining this diagram shows that it adsorbs carbon dioxide, but hardly adsorbs ethane, normal phthalate, and isobutane.

Therefore, the pore diameter is estimated to be approximately 3.3A. This product has a hardness of 3. It was OKq (Kiya type hardness tester).

Example 4 Carbide obtained by carbonizing lignite at a temperature of 8,000 ℃ for 2 hours was
75% by weight of the powder pulverized to 0.00 mesh or less and 25% by weight of an aqueous phenol solution were blended at room temperature, mixed well, and granulated with an extrusion molding machine at room temperature to a particle size of 2 to 3 mmφ. After drying this granule at a temperature of 110C for 2 hours,
Heat treatment was performed using a heating furnace at a temperature of 270C in a nitrogen atmosphere for 1 hour. A yield of 90% was obtained based on the dried granules.

FIG. 4 shows the adsorption crosstalk in the same method as in Example 1.

Considering this diagram, the amount of carbon dioxide adsorbed is quite large.
It can also be seen that a small amount of ethane is also adsorbed, and that both normal butane and insulin are adsorbed in very small amounts. Therefore, it is estimated that the pore diameter is approximately 4°. Unfinished products have a hardness of 2.0 Kg (Kiya type hardness tester)
Met.

Example 5 Carbide obtained by carbonizing lignite at a temperature of 800C for 2 hours was
85% by weight of the powder pulverized to 0.00 mesh or less and 15% by weight of the phenolic resin solution were blended at room temperature, mixed well, and passed through an extruder to granulate particles with a particle size of 2 to 3 WIlφ at room temperature. This granulated product was dried at 110C for 2 hours, and then heated in a nitrogen atmosphere at 350C for 2 hours using a heating furnace. The product yield was 88% based on the dried granules.

This example is shown for reference in the case of manufacturing under conditions outside the limitations of the present invention.

Next, we will show the adsorption properties of this product.

The adsorption isotherm obtained by the same method as in Example 1 is shown in FIG. Examining this figure, it is found that the adsorption amounts of carbon dioxide, ethane, n-butane, and isobutane are greater than those in Figures 1 to 4. The molecular diameter of isobutane is 5. Since it is OA, the pore diameter of this product is estimated to be approximately 6° OA or more.

As described above, the pore size of the product according to the present invention is about 3.3 to 4.
3A, and the hardness is 2.0-3.0 Kp. However, the pore size of the product obtained by methods other than the limitations of the present invention is approximately 6. O
It can be seen that the hardness is large at A or above, and the -hardness is weak at 0.2 Kp.

Recently, the separation of nitrogen and oxygen from air has been carried out using a sieve carbon material determined by pressure fluctuation adsorption method, but in this case it is suitable that the molecular sieve used has a pore diameter of about 3 to 4.3A. It is said that there are. The pore diameter of the product of the present invention is approximately 3.3 to 4.
Since there are only three people, I think it is suitable for this purpose.

According to the method of the present invention, the adsorption performance is improved.

A molecular sieve carbon material with excellent separation performance and strong strength can be easily manufactured at low cost.

[Brief explanation of drawings]

Figures 1 to 5 show carbon dioxide and ethane for the products manufactured in Examples 1 to 5, respectively. FIG. 2 is a diagram showing adsorption isotherms at 25 tr using normal butane and inbutane.

Claims (1)

[Claims] 1. Non-caking coal is carbonized at a temperature of 550 to 800 C to form a finely powdered carbide, which exhibits adhesiveness at room temperature, is water-soluble at room temperature, and has thermosetting properties, such as an aqueous phenol resin solution or starch paste. 20~
1. A method for producing a molecular sieve carbon material, which comprises blending and granulating the carbon material in a weight ratio of 30 to 30%, followed by heating at a temperature of 160 to 270C for 1 to 4 hours.