JP2008284568A - Tablet forming machine, and method for producing solid catalyst for synthesizing (meth)acrylic acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method where, in a tablet forming stage in the production of a solid catalyst for synthesizing (meth)acrylic acid, the precision in the weight of a formed body is improved, the process is stabilized, productivity is improved, and quality irregular spots in a formed part are reduced without changing the shape of the formed part. <P>SOLUTION: In the tablet forming machine where an upper rod and a lower rod are moved up and down, and solid catalyst powder for synthesizing (meth)acrylic acid or the powder of the precursor thereof (hereinafter referred to as raw material powder) is compressed and formed in a packing mortar hole provided at a packing mortar. A taper widened to the outer direction at a gradient of the repose angle of the raw material powder or above is formed at least on a part of the upper part in the packing mortar hole, and the opening area in the upper end face of the opening part is 1.5 to 3.5 times to the area of the lower end face in the opening part. The method for producing a solid catalyst for synthesizing (meth)acrylic acid is characterized in that forming is performing using the tablet forming machine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

 The present invention relates to a tableting machine and a method for producing a solid catalyst for synthesizing (meth) acrylic acid.

 As a method for producing a solid catalyst for synthesizing (meth) acrylic acid by vapor-phase catalytic oxidation of (meth) acrolein, a mixed solution or a slurry containing raw materials of catalyst constituent elements such as molybdenum and phosphorus is prepared, This mixed solution or slurry is dried to obtain a catalyst precursor powder, and then a powder containing a dried catalyst component or a catalyst precursor that obtains catalyst activity by the subsequent activation treatment (referred to as catalyst powder). ) Is known (for example, Patent Document 1). It is also known to perform tableting by mixing a lubricant release agent with a catalyst powder in order to improve the lubricity during tableting and the stability during molding when tableting. (For example, patent document 2).

However, in general, the catalyst powder obtained by this method is bulky because of its very small particle size, and the powder shape is often indefinite, so that the fluidity is poor. Therefore, when a powder mixture of catalyst powder or catalyst powder and additives (generally referred to as raw material powder) is subjected to a tableting molding process, a filling die hole for tableting molding provided in the filling die It is difficult for a predetermined amount of raw material powder to enter inside, resulting in a decrease in process stability and production speed during tableting. Furthermore, since the amount of the raw material powder to be tableted easily fluctuates, there arises a problem that the distribution of the weight and strength of the molded product becomes large. In particular, this problem becomes significant when the amount of raw material powder per molded body is increased. When a molded catalyst having a large weight or strength distribution is packed in a reactor, an unpredictable activity distribution can be generated in the reactor due to breakage or variations in packing density. In particular, since the heat of reaction is large in the oxidation reaction, hot spots may be generated due to the activity distribution, which may hinder stable operation.
In order to solve this problem, using a jig that moves the raw material powder, the raw material powder is forcibly pushed into the filling die hole for tableting, or the raw material powder input port adapted to the shape of the filling die hole It is also possible to install it. However, since large-scale construction is required, it is difficult to apply to those already on the production line.

On the other hand, as a method of improving the tableting machine when tableting powder that is likely to cause tableting troubles, the clearance between the filling mortar and the punches for tableting is specified, and air escapes from and adheres to the raw material powder. A method of scraping off the powder is known (Patent Document 3). In addition, when tableting is performed, the diameter of the filling mortar hole is increased by 4/100 to 8/100 mm with respect to the diameter of the ridge to reduce friction between the raw material powder during compression and the inner wall of the filling mortar hole. However, it is known to provide a slight inclination in the filling mortar to facilitate tablet release. The inclination angle is assumed to be 5 degrees from the vertical plane of the filling mortar hole (85 degrees on the basis of the mortar plane) in order to suppress powder scattering during compression (for example, Non-Patent Document 1). Further, in order to facilitate the release of the molded body after compression, there are those in which the angle provided in the filling mortar is 15 to 20 degrees from the vertical plane of the mortar (75 to 70 degrees on the basis of the mortar plane). (Patent Document 4).
JP-A-8-010621 JP-A-6-000374 JP 7-008540 A Japanese Patent Laid-Open No. 2003-010999 Tsuda Keisuke, Nogami Hisashi, “Pharmaceutical Development Basic Course X No.18 Formulation Engineering”, Jinshokan, March 1, 1969, P.A. 193

 However, in the prior art, it is known about the ease of movement of the upper and lower eyelids and the possibility of providing a taper at the periphery of the filling mortar hole to facilitate removal of the molded body after compression and molding. It is only being done. In addition, in the prior art, the shape of the molded catalyst (hereinafter referred to as catalyst molded body) must be changed, or large-scale equipment is added / improved to maintain and improve the charging efficiency of the raw material powder. Will be. In the present invention, the solid catalyst for synthesizing (meth) acrylic acid is molded in a desired shape, the accuracy of the individual weight of the molded catalyst (referred to as a catalyst molded body) is improved, the process is stabilized, and the productivity is improved. And it aims at reducing the quality spots for every catalyst molding.

  The tableting molding machine for molding the solid catalyst for synthesizing (meth) acrylic acid according to the present invention, the upper and lower punches move up and down to compress the raw powder in the filling die hole provided in the filling die. A molding machine for molding a solid catalyst for synthesizing (meth) acrylic acid, wherein at least a part of the upper portion of the filling mortar is formed with a taper that is widened outwardly, The opening area of the upper end surface of the upper opening of the filling mortar is 1.5 to 3.5 times the area of the lower end surface of the upper opening. The taper is preferably formed with a gradient equal to or greater than the repose angle of the raw material powder.

  The method for producing a solid catalyst for synthesizing (meth) acrylic acid according to the present invention includes a step of molding using a tableting molding machine for molding the solid catalyst for synthesizing (meth) acrylic acid.

 According to the tableting molding machine and the manufacturing method of the present invention, it is possible to mold a solid catalyst for synthesizing (meth) acrylic acid in a desired shape, improve the accuracy of the individual weight of the molded catalyst, and stabilize the process. , Improvement in productivity, and quality spots for each catalyst molded body can be reduced. Furthermore, in a tableting machine in which the filling die can be attached and detached, the present invention can be easily applied only by exchanging with a filling die suitable for the raw material powder.

An example of an embodiment of a tableting machine and a manufacturing method in the present invention will be described.
First, using FIG. 1 and FIG. 2, the tableting molding machine of the solid catalyst for the synthesis of (meth) acrylic acid according to the present invention will be described as an example. The tableting machine is not particularly limited, and industrially used equipment may be selected as appropriate.
FIG. 1 is a perspective view of a rotary tableting machine which is an example of the tableting machine. The rotary tableting machine 6 includes a rotary table 8 and an upper table 9 and a base 20 above and below the rotary table 8 with a center body 7 as an axis. The upper rod 16 is installed through the upper table 9, and the lower rod 18 is installed so as to move up and down from the pedestal, and is connected to a lifting device (not shown). The rotary table 8 includes a plurality of filling dies 10. Moreover, although the raw material powder container 22 is installed in the upper surface of the rotary table 8, it is being fixed to the center body 7 so that it may not interlock | cooperate with this table. In addition, the raw material powder container 22 is opened at a portion in contact with the rotary table 8.
FIG. 2 is a sectional view of the filling die. The filling die 10 is formed with a filling die hole 12 in which raw material powder is filled and molded. The filling die hole 12 is formed so as to penetrate the filling die 10 up and down. Further, the upper portion of the filling mortar hole 12 is provided with an upper opening 14 provided with a taper so as to widen the peripheral portion outward.

前記開口比を１．５未満とすると、テーパー部に導入される原料粉が十分確保できず、原料粉を効率的に充填臼孔１２へ取り込むことができない。一方、前記開口比が３．５を超えて設定されるとテーパー部に導入される原料粉は十分確保されるが、錠剤排出時に錠剤がテーパー部に引っかかり、工程不具合を生じやすくなる。したがって、本発明の実施においては該開口比が１．５〜３．５となるようなテーパーの深さＬをもって、上部開口部１４が設けられる。なお、図１、図２においては、テーパーは充填臼孔１２の上部の周縁部全体に設けられているが、形状は限定されることなくテーパーの勾配の角度と開口比の条件を備えれば一部分のみでも構わない。 The taper gradient of the upper opening 14 is represented by the value of θ in FIG. 2 when the upper surface of the filling die 10 is a horizontal plane. Here, if the angle θ of the taper gradient in the upper opening 14 is less than the angle of repose of the raw material powder to be used, the raw material powder introduced into the tapered portion is less likely to collapse and the fall into the filling mortar hole 12 is prevented. Therefore, the taper portion is provided with a gradient equal to or greater than the repose angle of the raw material powder.
In addition, the depth L of the tapered portion is set so that the opening area of the upper opening of the upper opening 14 (hereinafter referred to as the upper opening area) becomes a predetermined area. Specifically, the ratio of the upper opening area to the area of the lower end surface of the upper opening 14 (hereinafter referred to as the mortar cross-sectional area) is defined as the opening ratio, and the opening ratio is 1.5 to 3.5. A taper is provided at such a depth. This opening ratio is expressed by the following equation when the shapes of the upper opening 14 and the filling die hole 12 are a perfect circle when viewed from above the filling die 10. D represents the inner diameter of the upper end surface of the upper opening, and d represents the inner diameter of the lower end surface of the upper opening.

When the opening ratio is less than 1.5, the raw material powder introduced into the tapered portion cannot be sufficiently secured, and the raw material powder cannot be efficiently taken into the filling mortar hole 12. On the other hand, when the opening ratio is set to exceed 3.5, the raw material powder introduced into the tapered portion is sufficiently ensured, but the tablet is caught by the tapered portion when the tablet is discharged, and process defects are likely to occur. Therefore, in the practice of the present invention, the upper opening 14 is provided with a taper depth L such that the opening ratio is 1.5 to 3.5. In FIG. 1 and FIG. 2, the taper is provided over the entire peripheral edge of the upper portion of the filling mortar hole 12, but the shape is not limited as long as the taper slope angle and the aperture ratio are provided. Only a part may be used.

An example of the molding process of the tableting machine will be described. In the rotary tableting machine 6, the upper table 9, the rotary table 8 and the pedestal 20 rotate in conjunction with the arrow direction shown in FIG. 1. First, the lower punch 18 is raised and inserted into the filling mortar 12 by the lifting device. The degree of insertion of the lower eyelid 18 is determined by the density and weight of the catalyst molded body to be produced. In the case of high density or weight increase, the lower iron 18 is inserted shallowly and receives a larger amount of raw material powder. The raw material powder is always supplied and retained in the raw material powder container 22 by a raw material supply machine (not shown), and the raw material powder is in contact with the rotary table 8 at a fixed position. After the lower punch 18 is inserted, when the filling die 10 passes the lower part of the raw material powder container 22 by the rotation of the rotary table 8, the raw material powder falls from the upper opening 14 into the filling die hole 12.
Thereafter, the upper punch 16 is lowered by the lifting device and inserted into the filling mortar hole 12, and the raw material powder is compressed and molded. Next, while the upper rod 16 and the lower rod 18 compress the catalyst molded body, the upper end surface of the lower rod 18 is raised to the upper end surface of the upper opening 14, and when only the upper rod 16 is further raised, the catalyst molded body is filled with the filling die. Appears on top of 10 and is removed. By the above operations, the upper table 9, the rotary table 8 and the pedestal 20 are rotated so that the supply of raw material powder, compression / molding, and removal of the molded catalyst are continuously performed.

An example of the tableting machine used in the above description is to obtain a cylindrical catalyst molded body, but the shape of the catalyst molded body may be appropriately selected according to the nature and use of the catalyst. In addition to cylinders, shapes such as polygonal columns and star columns are listed, and the corners of the catalyst molded body are curved or planar chamfered, the columnar upper and lower surfaces are elliptical, and It is also possible to select the catalyst molded body itself having an elliptical sphere. The shape of the catalyst molding is determined by the shape of the filling mortar 12 and the shape of the surface where the upper punch 16 and the lower punch 18 are in contact with the raw material powder. Therefore, in order to make the shape of the catalyst molded body unaffected by the shape of the upper opening 14, the lowermost end surface of the state in which the upper punch 16 is lowered and inserted into the filling mortar hole 12 is the depth L of the tapered portion. It is preferable that it is provided so as to be positioned below. The density and weight of the molded catalyst are adjusted by adjusting the position of the lower punch 18 to control the amount of the raw material powder filled in the filling mortar hole 12 immediately before tableting, This is done in combination with the lowered position.
Furthermore, the obtained catalyst molded body can be subjected to physical treatment such as crushing, classification and drying, chemical treatment such as chemical immersion and chemical spraying, and heat treatment such as firing as necessary. .

There are no particular restrictions on the components of the preparation to (meth) catalyst for acrylic acid synthesis, composite oxide having a composition represented by the general formula _{P a Mo b V c Cu d} X e Y f Z g O h Product catalysts are preferred.
In the above general formula, P, Mo, V, Cu and O represent phosphorus, molybdenum, vanadium, copper and oxygen, respectively, X represents antimony, bismuth, arsenic, germanium, zirconium, tellurium, silver, selenium, silicon, tungsten And at least one element selected from the group consisting of boron and Y, at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, cobalt, manganese, barium, gallium, cerium and lanthanum Z represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a, b, c, d, e, f, g and h are atomic ratios of the respective elements. Where b = 12, a = 0.5-3, c = 0.01-3, d = 0.01-2, e = 0-3, f 0-3, a g = 0.01 to 3, h is an atomic ratio of oxygen required to satisfy the valence of each element.

An example of a method for preparing the catalyst powder will be described. First, a mixed solution or slurry containing raw materials for catalyst constituent elements such as molybdenum and phosphorus is prepared.
As a method for preparing the mixed solution or slurry, it is not necessary to limit to a special method, and a well-known method such as a precipitation method or an oxide mixing method may be used unless significant uneven distribution of components is involved. it can. Specifically, a mixed solution or slurry is prepared by appropriately dissolving or suspending a required amount of a raw material containing a catalyst constituent element in a solvent such as water. As raw materials for catalyst constituent elements, oxides, chlorides, sulfates, nitrates, carbonates, acetates, ammonium salts, halides and the like of each element can be used in combination. For example, examples of the molybdenum raw material include ammonium paramolybdate, molybdenum trioxide, molybdic acid, and molybdenum chloride. Examples of the phosphorus raw material include orthophosphoric acid, metaphosphoric acid, phosphorus pentoxide, pyrophosphoric acid, and ammonium phosphate. As raw materials for molybdenum and phosphorus, heteropoly acid compounds such as phosphomolybdic acid and ammonium phosphomolybdate may be used. Examples of the solvent include water, ethyl alcohol, acetone and the like, and preferably water is used. The content ratio (mass ratio) between the raw material and the solvent is usually preferably from 1: 0.1 to 1: 100, and more preferably from 1: 0.5 to 1:50 from the viewpoint of the physical properties of the slurry.

 Next, the mixed solution or slurry is dried to obtain a dried catalyst precursor as catalyst powder. There is no restriction | limiting in particular in the specific method of a drying process, Evaporation drying method, spray drying method, drum drying method, airflow drying method, stationary drying method, etc. are mentioned. The model of the dryer, the temperature during drying, the time, and the like are not particularly limited, and may be appropriately selected depending on the purpose. A substantially solid catalyst component may be obtained from the mixed solution or the aqueous slurry by drying, and the amount of the residual solvent in the dried product is not particularly limited. Examples of the shape of the dried product include powder and block shapes. If necessary, the dried product may be subjected to physical treatment such as pulverization and classification. In addition, some thermal and chemical treatment may be performed before the molding process by the tableting machine.

The catalyst powder may be used as a raw material powder for use in a tableting machine as it is. In order to improve moldability, a lubricant or a release agent may be mixed with the above catalyst powder to obtain a raw material powder. Any lubricant or mold release agent may be used as long as it does not adversely affect the performance of the catalyst. After molding of the catalyst, a nonflammable material is contained as it is, and if it is flammable, a method of calcination and removal at the time of catalyst activation is used.
Further, a binder may be used to increase the strength of the molded body of the solid catalyst for synthesizing (meth) acrylic acid. Any binder may be used as long as it does not adversely affect the performance of the catalyst. After molding of the catalyst, a nonflammable material is contained as it is, and if it is flammable, a method of calcination and removal at the time of catalyst activation is used.

 In the present invention, a taper having an opening ratio of 1.5 to 3.5 is formed at the upper part of the filling mortar, and the taper is formed with a gradient greater than the repose angle of the raw material powder. It is characterized in that it is effective in improving the filling efficiency and accuracy, and thus in suppressing the quality unevenness of the catalyst molded body.

Hereinafter, the manufacturing method of the solid catalyst for (meth) acrylic acid synthesis will be described in more detail with reference to examples. In addition, this invention is not limited to an Example.
(Preparation of raw material powder)
“Parts” in Examples and Comparative Examples means parts by mass.
Moreover, the catalyst composition was calculated | required from the raw material preparation amount of the catalyst component.
To 400 parts of pure water, 100 parts of molybdenum trioxide, 7.3 parts of 85 mass% phosphoric acid aqueous solution, 4.2 parts of vanadium pentoxide, 0.9 parts of copper oxide, and 0.2 parts of iron oxide are added and refluxed. Stir for 5 hours. After cooling this solution to 50 ° C., a solution prepared by dissolving 9.0 parts of cesium nitrate in 30 parts of pure water was added dropwise and stirred for 15 minutes. Thereafter, 37.4 parts of 29 mass% ammonia water was dropped while maintaining 50 ° C., and the mixture was stirred for 15 minutes to obtain an aqueous slurry. The obtained aqueous slurry was heated to 101 ° C., and concentration was started while stirring. When the viscosity of the slurry reached 0.70 Pa · s, the heating was stopped to obtain a concentrated slurry. The time it took to concentrate was 2 hours. The concentrated slurry was cooled to 70 ° C. and held for 2 hours. The viscosity of the concentrated slurry after the retention was 0.40 Pa · s. The concentrated slurry was heated to 101 ° C., and concentration was started again with stirring. During concentration, the temperature was maintained at 101 ° C., and when the viscosity of the slurry became 0.70 Pa · s and the specific gravity reached 1.64 × 10 ³ kg / m ³ , heating was stopped to obtain a concentrated slurry. The time to concentrate was 0.5 hours. The slurry immediately after concentration was dried at 120 ° C. with a drum dryer to obtain catalyst component powder. The moisture content of the obtained catalyst component powder was 1.0% by mass. The obtained catalyst component powder was further dried at 100 ° C. for 24 hours using a hot air dryer, and the moisture content was adjusted to 0.5 mass%. After naturally cooling to room temperature, 3 parts of graphite was added to 100 parts of the catalyst component powder and mixed uniformly. Table 1 shows the properties of the powder before and after mixing the graphite. A powder tester PT-N (manufactured by Hosokawa Micron Corporation) was used for measuring the properties of the powder.

ｍ：打錠成型体の平均重量
Ｄ：原料粉の嵩密度
Ａ：充填臼孔の断面積
ｈ：原料粉の充填高さ（充填臼上端面から下杵上端面までの長さ） (Tablet molding)
Using a tableting molding machine HT-12SS (manufactured by Hata Tekko Co., Ltd.), Examples 1 to 5 are the filling die 1 in which the inner diameter of the filling die hole is 5 mm, the taper gradient is 60 degrees, and the taper depth is 2 mm. used. Examples 6 to 10 used the filling die 2 in which the inner diameter of the filling die hole was 5 mm, the taper gradient was 45 degrees, and the taper depth was 2 mm. In Comparative Examples 1 to 6, the filling die 3 having an inner diameter of the filling die hole of 5 mm and having no taper was used. For the tableting molding of Example 1 and Comparative Examples 1 and 2, the raw material powders Nos. No. 1 after mixing with graphite is used as the raw material powder, and the tableting molding of Examples 2 to 10 and Comparative Examples 3 to 6 is the raw material powder No. 1 described in Table 1. 2 was used as raw material powder after graphite mixing. In the tableting machine, 12 filling dies are arranged on the circumference of the rotary table, and 12 molded bodies are obtained by one rotation. The results are shown in Tables 2, 3, and 4.
In the table, the production speed indicates the operating conditions set in the tableting machine in this example, and the filling efficiency is the theoretical weight of the tableting molding determined by the position of the lower punch and the bulk density of the raw material powder. It is expressed by the weight ratio of the actual tableted molded product with respect to the above, and is represented by the following formula.

m: Average weight of the tableting molding D: Bulk density of raw material powder A: Cross-sectional area of filling mortar h: Filling height of raw material powder (length from upper end surface of filling die to upper end surface of lower punch)

 As shown in Table 2, the filling mortar No. 1 having a taper is prepared. In Example 1 using No. 1, a filling mortar no. Compared with Comparative Examples 1 and 2 using No. 3, improvement in the filling efficiency of the raw material powder and the accuracy of the filling weight were observed. In Tables 3 and 4, the filling die No. Compared to Comparative Examples 3 to 6 using No. 3, filling die No. 3 having a tapered portion. 1 and no. As a result of using No. 2, it was found that filling weight control and filling efficiency were excellent. Furthermore, filling die No. Examples 2-5 using No. 1 and filling die No. In the comparison of Examples 6 to 10 using No. 2, the filling die No. 1 in which the taper is formed with a gradient greater than the angle of repose of the raw material powder. When 1 was used, it turned out that the filling efficiency is more excellent.

It is a perspective view of the rotary tableting machine which is an Example of this invention. It is sectional drawing of the filling die which is an Example of this invention.

Explanation of symbols

6 Tableting molding machine 7 Upper table 8 Rotary table 9 Central body 10 Filling die 12 Filling die hole 14 Opening portion 16 Upper punch 18 Lower punch 20 Base 22 Raw material powder container D Opening inner diameter d Filling die inner diameter L Taper depth θ Taper slope angle

Claims (3)

  A tableting molding machine in which an upper punch and a lower punch are moved up and down to compress and mold a raw material powder in a filling die hole provided in a filling die to form a solid catalyst for methacrylic acid synthesis, At least a part of the upper portion of the filling mortar hole is tapered outwardly, and the opening area of the upper end surface of the opening of the filling mortar hole is 1 with respect to the area of the lower end surface of the opening portion. A tableting machine characterized in that it is 5 to 3.5 times.   The tableting machine according to claim 1, wherein the taper is formed with a gradient equal to or greater than an angle of repose of the raw material powder.   A method for producing a solid catalyst for synthesizing (meth) acrylic acid, comprising a step of molding using the tableting molding machine according to claim 1 or 2.

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