JPS6227322A - Production of molded body of zeolite - Google Patents

Abstract

PURPOSE:To obtain molded bodies of zeolite having superior strength by a simple process at a low cost without exerting unfavorable influence on adsorbing performance peculiar to zeolite by adding heavy oil separated from coal and/or petroleum to powdery or granular zeolite, kneading and molding them and baking the resulting molded bodies. CONSTITUTION:Heavy oil separated from coal and/or petroleum is added as a binder to powdery and/or granular zeolite, they are kneaded and molded, and the resulting molded bodies are baked at 400-700 deg.C. Heavy oil contg. >=80% volatile matter, e.g., coal tar or ethylene bottom oil is preferably used as the heavy oil as the binder. The zeolite may be any of natural and synthetic substances. The proper grain size of the zeolite is <=1mm.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to dehydrating agents, molecular sieve type adsorbents, cation exchange agents,
The present invention relates to a method for manufacturing zeolite molded bodies used as catalysts in various fields.

(Prior art) Zeolite has excellent NFC adsorption properties, ion exchange ability,
Due to its catalytic activity, it has been widely used as a dehydrating agent, molecular sieve adsorbent, cation exchange agent, catalyst, etc.

This zeolite is rarely used as a powder, and is usually used in the form of a zeolite molded body, which is formed by molding the zeolite powder and then firing it to increase its mechanical strength.

Conventionally, zeolite molded bodies have been produced by a wet method, and inorganic substances such as bentonite, kaolin, diatomaceous clay minerals have been used as binders. Clay minerals have the effect of strengthening the bond between particles that make up zeolite aggregates or molded bodies, but most of the clay minerals used as binders remain as solid components in the final product even after firing. Therefore, there is a problem that the inherent adsorption properties, ion exchange ability, and catalytic activity of zeolite are impaired. In addition, when clay minerals are used as a binder, swelling and contraction of the clay minerals occur due to adsorption and release of water, and as a result, repeated adsorption and regeneration of water causes the mechanical strength of the zeolite molded body to increase. Therefore, in order to overcome the drawbacks of Ton et al., a method for producing zeolite molded bodies using a cellulose compound alone or in combination with a clay-based binder as a binder (Japanese Patent Application Laid-Open No. 59-269
23), a method for producing a zeolite molded body using sodium alginate alone or in combination with a clay-based binder as a binder (Japanese Unexamined Patent Publication No. 59-26922), etc. (The invention solved the problem). According to these methods, the amount of clay-based binder used can be reduced, and the above-mentioned drawbacks of clay-based binders can be suppressed.

However, all of these methods belong to the wet molding method, and molding is usually carried out in the presence of about 30% moisture, so the molded product contains a large amount of moisture. Ru. If moisture was present in the molded product, cracks would occur in the zeolite molded product due to the rapid evaporation of water during the firing process, and the crystal structure of the zeolite itself would deteriorate or be destroyed9.
Therefore, in the production of zeolite molded bodies using the conventional wet method, drying is performed at a temperature of around 100°C before calcination without adversely affecting the ability to remove moisture.
It is an object of the present invention to provide a method for manufacturing a zeolite molded body, which allows a zeolite molded body with excellent strength to be manufactured at low cost by a simple manufacturing process.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides powdery and/or
Alternatively, when molding granular zeolite to produce a zeolite molded body, coal-based and/or petroleum-based heavy oil is added as a binder and mixed, followed by molding.
The present inventors repeatedly conducted molding experiments of powdered and/or granular zeolite using various binders, and found that coal-based or petroleum-based heavy Quality oil has a strong cohesive force, and can be easily molded using these tools.
By subsequently firing the molded body at a temperature range of 400 to 700°C, a zeolite molded body with strong bonding between particles and excellent mechanical strength and abrasion resistance as well as excellent gas adsorption performance is produced. I found out that I can get .

The coal-based or petroleum-based heavy oil used in the present invention is not particularly limited, but includes coal-based or petroleum-based binders with a volatile content of 80 parts or more, such as coal tar, ethylene bottom oil, etc. suitable. This is because these binders are liquid at room temperature and do not require heating during mixing.In the production of the zeolite molded body according to the present invention,
Natural or synthetic zeolites can be used as the zeolite material.These zeolites are usually
Although it is used in powder or granular form, it is preferably in fine powder or fine granule form, and suitably has a particle size of at least 1 mm or less.

The amount of coal-based and/or petroleum-based heavy oil used as a binder varies depending on the type and viscosity of the heavy oil and the particle size of the zeolite material used, but in general, it is If the amount of these heavy oils used is less than 10 wtqb, the cohesive force during molding will be insufficient and the product will not be processed. The mechanical strength and abrasion resistance of the zeolite molded body become insufficient. On the other hand, if the amount of these heavy oils used exceeds 40wt% based on the zeolite material,
The pores of the zeolite are blocked by the remaining products n1
Zeolite's inherent adsorption performance begins to decline.

For fine powder or granules of zeolite, the above amount of coal-based and/-! A binder made of oil or petroleum-based heavy oil is added and mixed, and then the mixture is molded using a molding machine in a conventional manner. The molded product is then fired at a temperature range of 400 to 700°C without going through a humidity conditioning or drying process. If the firing temperature is less than 400°C, the thermal decomposition of heavy oil will be insufficient. First, the mechanical strength and abrasion resistance of the obtained zeolite molded body become insufficient.

In addition, if the temperature exceeds 700°C, thermal decomposition of the zeolite itself will occur, resulting in deterioration of adsorption performance. C calcination is preferably performed in an inert gas atmosphere such as nitrogen. The time varies depending on the processing temperature, but usually at least 0.5 hour is required. If the firing time is less than 0.5 hours, the thermal decomposition of the binder will be insufficient and non-uniform, which is not preferable.

(Function) As mentioned above, coal-based or petroleum-based heavy oils have strong cohesive force and provide good moldability, so by using these heavy oils as binders, conventional Unlike the wet molding method, it is unnecessary to adjust the moisture content of the mixture to about 30% to increase the cohesive force of the mixture, and the moisture content in the resulting green compact can be kept low. . Therefore, even if firing is performed immediately after molding, there will be no collapse of the molded body or deterioration or destruction of the zeolite crystal structure due to rapid water evaporation. Therefore, the drying step before firing can be omitted. .

In addition, during the firing process of the molded body, coal-based or petroleum-based heavy oil is thermally decomposed and generates a large amount of gas, and the bond between the zeolite particles becomes porous due to the foaming phenomenon. . Moreover, in the case of petroleum-based heavy oil, the amount of thermal decomposition products remaining in the final molded product is small compared to clay-based binders, so zeolite's inherent adsorption The phenomenon of performance loss does not occur.

(Example 1) To 1 kg of natural mordenite pulverized to a particle size of 100 mesh or less, 0.23 kg of coal tar with a volatile content of 83.8 was added and mixed in a kneader for 30 minutes. After mixing, the mixture was molded into a shape of 178'' (diameter: 3 mm, length: 4.5 mm) using a molding machine, and then baked at a temperature of 550'C for 4 hours to obtain a sample.

Compressive fracture strength was measured using a hardness tester for 50 samples of 1/8" pellets. In addition, 1/8" pellets Q, 02 kg were packed into a stainless steel adsorption tower with an internal volume of 0.0461 (D). The adsorption isotherm of carbon monoxide was measured using carbon monoxide having a purity of 99.94 at a temperature of 20° C. The results are shown in Table 1 and FIG.

For comparison, 0.30 kaolin-type clay was added to 1 klil of natural mordenite prepared by crushing in the same manner as above.
kg and mix in a V-type mixer for 30 minutes, then 3
After adding SOCR water and mixing with a kneader for 30 minutes, it was molded, dried at a temperature of 100'C for 3 hours, and then fired at a temperature of 550°C for 3 hours to obtain a comparative sample of 1/8" pellet. The compressive strength and carbon monoxide adsorption isotherm of the obtained sample were measured in the same manner as the sample of the above Example.The results are also shown in FIG. 1 and Table 1.

As is clear from the results shown in Table 1, by using coal tar as a binder, a zeolite molded body with higher strength can be obtained compared to Comparative Example 1 using clay mineral as a binder using the conventional method. Furthermore, as is clear from the carbon monoxide adsorption isotherm shown in FIG. It is superior to the gas adsorption performance (x mark) of the zeolite molded body.

(Comparative Examples 2 and 3) Samples were obtained by baking 1/8" pellets obtained by molding in the same manner as in Example 1 at temperatures of 350°C and 750°C for 4 hours each. The compressive strength and carbon monoxide adsorption amount at a temperature of 20° C. and an equilibrium pressure of 2 atm were measured for the obtained sample in the same manner as in Example 1. The results are shown in Table 2.

As shown in Table 2, in Comparative Example 2, which was fired at a temperature lower than the firing temperature range of the present invention, the strength of the zeolite molded body was lower than that of Comparative Example 1, which was made using a conventional method and used clay mineral as a binder. On the other hand, in Comparative Example 3, a zeolite molded body with high strength was obtained by performing calcination at a temperature higher than the calcination temperature range of the present invention. Adsorption performance decreases.

Table 2 (Effects of the Invention) As described above, according to the present invention, a zeolite molded body with excellent strength can be produced without adversely affecting the adsorption performance of zeolite. The coal-based or petroleum-based heavy oil used in the present invention is easily and inexpensively available, and zeolite molded bodies can be manufactured at low cost.Furthermore, these binders have a high cohesive force. Since it has strong and good moldability, there is no need to add a large amount of water before molding, and the drying process that was essential in conventional methods can be omitted, simplifying the manufacturing process of zeolite molded bodies. can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a graph showing carbon monoxide adsorption isotherms (20° C.) of the zeolite molded bodies obtained in Example 1 and Comparative Example 1.

Claims (1)

[Claims] (1) Coal-based and/or petroleum-based heavy oil is added as a binder to powdered and/or granular zeolite, mixed and molded, and the resulting molded body is fired at 400 to 700°C. A method for producing a zeolite molded body characterized by: