JPS6295141A - Preparation of coated catalyst - Google Patents

Abstract

PURPOSE:To prepare a coated catalyst tightly sticking on a carrier by subjecting a carrier group to violent planetary motion and simultaneously scattering catalyst powder for coating it and spraying a binder liquid and subjecting it to planetary motion while supplying slit air after stopping the supply of both raw materials. CONSTITUTION:A centrifugal fluidized bed is formed by giving planetary motion a carrier group in 150-800cm/sec peripheral speed due to a granulator while ventilating slit air from an under part of a system. Simultaneously, the carrier group is coated by scattering catalyst powder to the inside of the system and together spraying binder liquid through the other port with 70-110% saturated water absorption quantity of the catalyst powder. After stopping the supply of both raw materials, the carrier group is dried with slit air and finished while continuing the planetary motion and regulating the grains of a product. Thereby a coated catalyst tightly sticking on the carrier can be prepared in a simple process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a coated catalyst, and more specifically, the present invention relates to a method for producing a coated catalyst, and more specifically, a method for producing a coated catalyst, in which a group of carriers is made to move violently in a planetary motion, and at the same time, a coated catalyst powder is scattered and a binder liquid is sprayed. This invention relates to a method of firmly adhering catalyst powder for coating onto a carrier while maintaining a constant moisture content in the carrier and catalyst powder, and supplying slit air from below to strengthen the mixing, flow, and collision of the two. .

[Conventional technology and problems]

Supporting a catalyst on a carrier is well known and is widely used in the art. The catalyst can be supported on a carrier using the homogeneous catalyst method, in which the catalyst powder and carrier powder are mixed uniformly and then molded into an appropriate shape, and the coated catalyst method, in which the catalyst powder is coated on the carrier. etc. are common, and the present invention provides the latter method.

The advantage of coating a catalyst powder on a carrier is that the amount of expensive catalyst used per unit reaction volume can be suppressed and an inexpensive catalyst can be produced. Another great advantage is that the properties of the catalyst can be improved. In other words, in the case of a reaction that generates intense heat, such as an oxidation reaction, a uniform catalyst cannot sufficiently remove the generated heat, which may cause problems in reaction control, or cause undesired secondary oxidation reactions, resulting in a decrease in selectivity. However, if a coated catalyst is used, local heating can be avoided due to heat conduction to the support material, and reaction controllability, selectivity, etc. can be improved.

Although coated catalysts have the above-mentioned advantages, they have not been widely used industrially because the technology for firmly adhering the catalyst to a carrier has not yet been sufficiently established.

For example, Japanese Patent Publication No. 58-26973 discloses that an inert carrier having a diameter of at least 20 μm is pre-wetted with water;
A method has been proposed in which a dry powdered catalyst material is then added thereto and the mixture is slowly stirred until the powder no longer adheres. However, when using this method, the amount supported varies depending on the pre-wet state of the carrier, and it is necessary to measure the water content and the amount supported in advance. In addition, after carrying, in some cases,
It requires a process of gentle shaking to remove loosely adhered catalyst, which is an industrial problem, and is also unsatisfactory in terms of strength, as peeling of 2.5 to 29.9% was observed in abrasion tests. It's not possible.

Furthermore, Japanese Patent Laid-Open No. 58-3644 proposes a method of spraying a suspension of a coating catalyst onto a fluidized carrier. However, when using this method, if soluble substances exist, they will be eluted into the suspension, and some of the eluted catalyst will enter the pores of the carrier during the coating process, making it impossible to completely coat the catalyst. There was a problem that the advantages of the coated catalyst were lost. Furthermore, there are drawbacks such as the fact that the catalyst itself may change due to the elution of the active substance, resulting in a decrease in activity.

As described above, none of the conventional methods are industrially satisfactory, and there has been a desire to develop a method for producing a coated catalyst firmly adhered to a carrier using a simple process.

[Means for solving problems]

The inventors of the present invention have conducted extensive studies to solve these problems and have arrived at the present invention.

That is, in the present invention, a peripheral speed of 1 by a granulating device having a rotatable component is achieved while a slit air is vented from below the system.
With strong mechanical mixing at 50 to 800 cm/sec, a planetary motion is applied to the carrier group to form a centrifugal fluidized bed. At the same time, the catalyst powder is dispersed into the system and the binder liquid is substantially poured from a separate port. 70 to 1 of the saturated water absorption amount of the catalyst powder
The coating process of spraying in a range of 10% and the finishing process of drying with a slit air while sizing the product by continuing the planetary motion after stopping the supply of both raw materials are carried out in the same system. This is a method for producing a coated catalyst, characterized in that it is carried out by:

In the process according to the invention, a corresponding granulation device is employed to impart a planetary motion to the carrier mass through intensive mechanical mixing and to form a centrifugal fluidized bed.

For example, it has been found that the use of a centrifugal fluid coating granulator (manufactured by Freund Sangyo Co., Ltd.) is particularly advantageous. This device is designated as Special Publication No. 10878, Special Publication No. 46-10878.
These are described in various publications such as No.-22544 and Japanese Patent Publication No. 54-992. In other words, by combining a rotatable dish-shaped part and a curved fixed wall that smoothly connects with the dish-shaped part, solid particles are made to flow (spiral circulation flow) using centrifugal force, gravity, and frictional force, thereby improving fluidity and polishing. powder and solid powder,
This improves the spreadability of the liquid and also improves the drying efficiency by supplying air from the bottom of the fluidized solid bed. Further, by associating the 8-unit with an automatic control device, it is possible to carry out continuous operation fully automatically.

Here, in the above device, the rotation of the dish-shaped portion is preferably 150 to 800 c at a circumferential speed to induce a centrifugal force sufficient to give planetary motion to the carrier by strong mechanical mixing.
m/sec'. Here, the planetary motion refers to the rotation and revolution motion of the carrier obtained by rotation of the dish-shaped portion and ventilation with slit air, which will be described later.

The slit air venting from below the system, that is, from below the curved fixed wall of the above device, is used to mix the carrier and catalyst powder in the system.
It promotes flow and collision, and serves to maintain a constant moisture content between the two. The amount varies depending on the properties of the carrier and catalyst powder, and it is necessary to determine the optimum amount experimentally, but it is usually 20
~20 ONl 1 min/1-carrier. Further, the temperature of the slit air can be arbitrarily selected each time to the optimum temperature for keeping the humidity in the system constant in the coating process and drying the product in the finishing process.

The method of the present invention is not limited by the type of target carrier or the type of catalyst powder to be coated.

The carrier used is advantageously inert to the reaction, and examples of this type of carrier that are commonly used include silica, alumina, alumina-silica, silicon carbide, titania, and zirconia. Particularly preferred supports are low surface area silica, alpha alumina, silicon carbide. Any type of carrier can be used as long as it is in the form of a block. However, in consideration of workability, a spherical shape is advantageous, and a diameter of 1 to 10 mm is selected. Further, it is more preferable that the surface of the carrier is rough.

As the catalyst powder to be used, any type of catalyst that has been commonly used can be used in the present invention. For example, preferred catalysts include alkali metals, alkaline earth metals, V lCrlAg as active catalyst components.
lTl% MOLW %Mn-Fe% Cos N1%
Cus Zn, In, TI, Sn, Sm, T
a.

Examples include catalyst materials containing one or more elements such as Sb, Bi, P, As, and Si. In particular, vanadium-based catalyst materials containing vanadium and molybdenum-based catalyst materials containing molybdenum are useful.

The particle size of the catalyst powder to be coated must be at least smaller than the particle size of the carrier used, and is preferably substantially 250 μm or less. The ratio of the catalyst powder to the carrier is not particularly limited and is necessarily determined by the activity of the catalyst, but the catalytically active component is usually selected from a range of 10 to 300% by weight based on the weight of the carrier.

Water is generally used as the binder liquid that serves to firmly adhere the catalyst powder onto the carrier.

The amount is substantially 70 to 110 of the saturated water absorption amount of the catalyst powder.
It is desirable to supply in the range of χ, and although it depends on the type of catalyst, the amount is usually about 173 to 174 based on the weight of the catalyst. Also, polyvinyl alcohol instead of water,
It is also possible to spray an aqueous solution of an organic adhesive such as carboxymethyl cellulose or hydroxyethyl cellulose, or an aqueous silica sol solution.

Following the above coating process, a finishing process is performed.

In the finishing process, after stopping the supply of catalyst powder and binder liquid, the above planetary motion is continued to size (compress) the product.
At the same time, this is dried using a slit air.

Incidentally, after the completion of the above finishing step, it is of course possible and preferable to take out the produced coated catalyst outside the system and further dry it in a dryer.

〔Effect of the invention〕

Thus, the coated catalyst produced by the method of the present invention is
In principle, it can be used as a catalyst for any type of reaction system, but from the perspective of taking advantage of the advantages of coated catalysts, it is particularly effective when applied to exothermic reactions. For example, oxidation or ammoxidation of olefins, oxidation of unsaturated aldehydes,
Examples include reactions involving intense heat generation such as oxidation or ammoxidation of aromatic compounds, oxidation of alkylpyridines, and dealkylation.

〔Example〕

The method of the present invention will be explained in more detail below with reference to Examples and Reference Examples.

(Vanadium-based catalyst material) Example 1 V+Cro, Jgo, 1603. bz (1
5% by weight) -Ti02 (85% by weight) was prepared, and 45% by weight was prepared.
After baking at 0°C for 3 hours, this was crushed (80me
(passed through sh) to obtain catalyst powder.

Next, as a device, a centrifugal flow type coating granulator CF
-360 (manufactured by Freund Sangyo Co., Ltd.), the carrier (α-Aha, 211+IIlφ) was placed in the coating bath.
) 1.33 kg was input, the rotating plate was rotated at 17 Orpm, and air heated to 60°C was blown through the lower slit at a rate of 100 ff/min to mix the carrier group vigorously and cause it to move planetarily. .

On this fluidized carrier, the catalyst powder (2 kg) obtained above was sprinkled at a rate of 70 g/min using an automatic powder feeder, and at the same time, 2 kg of 0.3% poval aqueous solution was sprayed using a spray gun.
It was sprayed at a rate of 0 m7/min. After 29 minutes, the supply of catalyst powder was stopped, and after 30 minutes, the supply of Poval aqueous solution was stopped.

Next, while continuing the planetary flow, air was blown at a rate of 4002/min to size and dry the catalyst. After 40 minutes, add poval aqueous solution at a rate of 20+r+7/min to 30%
Sprayed for seconds. After 45 minutes, the work was completed. Furthermore,
Take this out of the system, dry it in a dryer, and then
It was calcined for 3 hours to obtain a coated catalyst.

The obtained coated catalyst was vigorously stirred for 15 minutes on a 16N+esh screen (Rottub standard sieve shaker 5S-1).
00, manufactured by Marubishi Kagaku Kikai Seisakusho Co., Ltd.), the degree of wear was measured and found to be 0.2%.

In addition, as a result of conducting a strength test on 100 catalysts by dropping the coated catalyst from above 31 onto an iron plate, peeling of the coating or cracking was not observed in all of the catalysts.

Example 2 A coated catalyst was produced in the same manner as in Example 1 except that the binder liquid was changed to a 3% silica sol aqueous solution.

The obtained coated catalyst had an abrasion degree of 0.2%, and no peeling or cracking of the coating was observed in the strength test.

(Molybdenum-based catalyst material) Example 3 Mo+zFe7.5BizKo, 40so, s
(33% by weight)-5iO□ (67% by weight),
After baking at 60°C for 4 hours, this was crushed (8Qm
(passed through esh) catalyst powder was obtained.

Moreover, the same apparatus as in Example 1 was used.

In the coating tank, carrier (α-A1203.3mmφ) 2
kg, the rotating plate was rotated at 170 rpm, and the air heated to 60°C through the lower slit was heated to 1004/kg.
The carrier group was mixed vigorously and planetary by blowing at a rate of 1.5 min. On this fluidized carrier, 100 g/100 g of the catalyst powder (2 kg) obtained above was added using an automatic powder feeder.
At the same time, use a spray gun to spray at a rate of 0.
A 3% aqueous poval solution was sprayed at a rate of 30 mZ/min.

After 20 minutes, the supply of the catalyst powder was terminated, and at the same time, the supply of the Poval aqueous solution was also terminated.

Next, 7. SN While continuing the star motion, the air is
The catalyst was sized and dried by blowing at a rate of 0.002/min. After 30 minutes, the work was completed. Furthermore, this was taken out of the system, dried in a drier, and then calcined at 500° C. for 3 hours to obtain a coated catalyst.

The obtained coated catalyst was tested in the same manner as in Example 1, and the results were as follows:
The degree of wear was 0.4%, and no peeling or cracking of the coating was observed in the strength test.

Example 4 MO+JitCOaFezT1 by a known method (normal method)
A catalyst having a composition of o and as was prepared and pulverized (passed through 60 mesh) to obtain a catalyst powder.

The carrier to be charged was 1.33 kg, and the catalyst powder (2
kg) and the spraying speed of the binder liquid were set to 9.
A coated catalyst was produced in the same manner as in Example 3 except that the rates were changed to 1 g/min and 25 rnl/min. Note that a similar pattern was adopted for each processing time.

The obtained coated catalyst had an abrasion degree of 0.2%, and no peeling or cracking of the coating was observed in the strength test. Furthermore, this was put into an electric furnace heated to 400°C, and after 3 minutes, it was taken out to room temperature and rapidly cooled. This heating and cooling process was repeated 10 times, but there was no peeling or cracking of the coating.

Example 5 Example 4 except that the binder liquid was changed to water (single)
A coated catalyst was produced in the same manner as above.

The resulting coated catalyst had an abrasion degree of 0.43%, and in the strength test, cracks occurred on the coated surface of 1 out of 100 grains.
No peeling was observed.

Examples 6 to 12 Catalysts having the catalyst compositions listed in Table 1 were prepared using known methods described in Japanese Patent Publications No. 51-11603, Japanese Patent Publication No. 51-12604, and Japanese Unexamined Patent Publication No. 146288/1983. was prepared and pulverized (passed through 60 mesh) to obtain catalyst powder.

A coated catalyst was produced in the same manner as in Example 4, except that the catalyst powder obtained above and the amount supported were changed.

The results of the strength test of the obtained coated catalyst are shown in Table 1.

Table 1 (dealkylation of β-picoline) Reference column 1 Reaction tube filled with the coated catalyst 6o produced in Example 1 (
(inner diameter 271φ), β-picoline:water:air=1:16
A mixed gas having a composition (volume ratio) of :12 was supplied for a contact time of 6.4 seconds to cause a reaction. For comparison, the same catalyst powder was molded into a tablet shape and then calcined at 400° C. for 3 hours, and the same treatment was performed using a tablet catalyst obtained.

The reaction results were as shown in Table 2.

Table 2 (Oxidation of propylene) Reference Example 2.3 Example 3 (corresponding to Reference Example 2) and Example 4 (Reference Example 3)
A reaction tube (corresponding to
Inner diameter 27n+mφ), propylene:air:nitrogen:water=
Composition of 6: 37: 34.1: 22.8 (
A mixed gas of a volume ratio) was supplied for a contact time of 5.5 seconds to cause a reaction. For comparison, the same catalyst powder was molded into a tablet shape and then calcined at 500° C. for 3 hours. The tablet catalysts were then treated in the same manner.

The reaction results were as shown in Table 3.

Proceeding Officer (Authentication 1) November 18, 1985 1, Indication of the case Patent Application No. 60-232361 2, Name of the invention Method for producing coated catalysts 3, Person making the amendment Relationship with the case Patent applicant (290) Daicel Chemical Industries, Ltd. 4, Agent Nakai Building, 1-3 Nihonbashi Yokoyama-cho, Chuo-ku, Tokyo Column 6 of the detailed explanation of the invention in the specification, Contents of amendment (1) Specification page 8, lines 11-12 "Vanadium" and "vanadium-based catalytic material" on page 8, line 12 are corrected to "vanadium" and "vanadium-based catalytic material," respectively. Catalytic Substances)” and Correction Procedures (from Fuzheng Shue) January 13, 1985

Claims (1)

[Claims] Peripheral speed of 150 to 800 c using a granulator with rotatable components while venting slit air from below the system
With strong mechanical mixing at m/sec, a centrifugal fluidized bed is formed by imparting planetary motion to the carrier group. At the same time, the catalyst powder is dispersed into the system, and the binder liquid is substantially mixed with the catalyst powder from a separate port. A coating process in which the product is sprayed in a range of 70 to 110% of the saturated water absorption of A method for producing a coated catalyst, characterized in that it is carried out continuously in the same system.