JPH067669A - Packing method of catalyst for synthesizing acrolein and acrylic acid - Google Patents

Abstract

PURPOSE:To reduce the degradation or the disintegration of a catalyst at the time of allowing a molded catalyst or carried catalyst for synthesizing acrolein and acrylic acid to fall to be packed into a fixed bed reactor. CONSTITUTION:The catalyst is allowed to fall to be packed by interposing a string like material having a shape and thickness, which does not prevent to allow the catalyst to fall into the reactor. As a result, it is not necessary for the molded catalyst or carried catalyst to have excessive mechanical strength and the restriction about catalyst design is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for packing a molded catalyst or a supported catalyst for the synthesis of acrolein and acrylic acid in a fixed bed reactor.

[0002]

2. Description of the Related Art Generally, when a molded catalyst or a supported catalyst is dropped and packed into a fixed bed reactor from above, the catalyst itself has a mechanical strength higher than a certain level in order to prevent the catalyst from being pulverized or broken due to a physical impact at the time of dropping. It is necessary to give strength or to devise some kind of filling method.

The mechanical strength of the catalyst can be improved to some extent by adjusting the molding pressure or devising the molding or supporting operation. However, a catalyst whose mechanical strength is increased by such a method generally has a small specific surface area of the catalyst, the number of active sites effective for the reaction is reduced, and the pore distribution effective for the reaction cannot be controlled. Due to the above reasons, the yield of the target product is low, which is not practical. From an industrial point of view, there is a demand for a method of filling a reactor with a minimized powdering / disintegration of a molded catalyst or a supported catalyst having a low mechanical strength.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a packing method which causes less powdering and disintegration when packing a molded catalyst for acrolein and acrylic acid synthesis or a supported catalyst in a reactor.

[0005]

According to the present invention, a fixed bed reactor is dropped and filled with a molded catalyst or a supported catalyst for synthesizing acrolein and acrylic acid by vapor-phase catalytic oxidation of propylene with molecular oxygen. At that time, in the reactor,
A method for filling a molded catalyst or a supported catalyst for synthesizing acrolein and acrylic acid, characterized in that at least one string-shaped substance having a shape and a thickness that do not substantially prevent the catalyst from falling is interposed.

When the molded catalyst is used in the present invention, its shape is not particularly limited, and it may be spherical,
Columnar, cylindrical, star-shaped ordinary tableting machines, extrusion molding machines,
What is molded by a rolling granulator or the like is used. When a supported catalyst is used, the type of carrier is not particularly limited, and usual carriers such as silica, alumina, silica-alumina, magnesia, titania, etc. are used. Also, the shape is not particularly limited, and spherical,
Examples thereof include a cylindrical shape, a cylindrical shape, and a plate shape.

In the present invention, the form of the fixed bed reactor is not particularly limited, and it can be applied to reactors of various forms. In particular, it is a very effective means when applied to a narrow tube diameter and long tube length such as a multi-tube vertical reactor.

In the present invention, the material of the string-like substance inserted and interposed in the reactor is not particularly limited as long as it does not break or break due to contact with the falling catalyst. Further, the shape is not particularly limited as long as it is a shape and thickness that does not substantially prevent the catalyst from falling, and for example, a rod shape, a wire shape, a thread shape, a band shape, a tube shape, a chain shape, a plate shape, a spiral shape. And the like, each of which includes a branch shape, a brush bristle shape, a plate shape, and the like.

The length of the string-like substance inserted and interposed in the reactor is not particularly limited, but if it is too short, the effect of suppressing pulverization and disintegration at the time of filling the catalyst is lowered. The length is preferably such that it reaches the bottom of the reactor. There is no limit to the number of strings used, and the greater the number, the greater the effect of suppressing pulverization and disintegration during catalyst filling. However, if the number is too large, it may hinder the dropping of the catalyst. Therefore, select an appropriate number according to the shape of the string-like material to be inserted.

The string-like substance interposed in the reactor may be removed before the reaction is started, or may not be removed. If the shape and material of the string-like substance used do not affect the yield of the target product, it is not always necessary to remove it after filling the catalyst. If the string-like substance used is a material that can be easily burned or vaporized and removed by a heat treatment in a range that does not change the performance of the filled catalyst, appropriate heat treatment after filling the catalyst can be performed. It can also be removed.

However, when the shape and material of the string-like substance used are not as described above, it is preferable to remove them before the start of the reaction. At that time, it is extremely difficult to pull out the string-like substance from the upper portion after the filling of the catalyst into the reactor is completed. Therefore, a method of gradually raising the string material from the upper portion at the same time as filling the catalyst is preferable.

As a means for interposing the string-like substance in the reactor, an appropriate method such as inserting it in the reactor and suspending it can be adopted. Further, depending on the shape and material of the string-like substance, it may be placed on the bottom of the reactor.

In the present invention, a catalyst having a composition represented by the following general formula is preferably used as a molding catalyst or a supported catalyst for synthesizing acrolein and acrylic acid by vapor-phase catalytic oxidation of propylene with molecular oxygen. . In the formula _{Mo a Bi b Fe c A d} Z e Y f Z g Si h O i ( wherein, Mo, represents Bi, Fe, Si and O represent molybdenum, bismuth, iron, silicon and oxygen, A is nickel And / or cobalt, X is magnesium, zinc,
At least one element selected from the group consisting of manganese, tin and lead, Y is at least one element selected from the group consisting of phosphorus, boron, sulfur, tellurium, selenium, germanium, tungsten and antimony, and Z is At least one element selected from the group consisting of potassium, sodium, rubidium, cesium and thallium is shown. However, a, b, c, d, e, f, g, h, and i represent the atomic ratio of each element, and when a = 12, 0.01 ≦ b ≦ 3,
0.01 ≦ c ≦ 5, 1 ≦ d ≦ 12, 0 ≦ e ≦ 5, 0 ≦ f
≦ 5, 0.001 ≦ g ≦ 1, 0 ≦ h ≦ 20, and i is the number of oxygen atoms required to satisfy the valence of each component. )

In the catalyst having the composition represented by the above general formula, the raw material of the element which is the catalyst component is not particularly limited, but it is usually an oxide or a chloride capable of forming an oxide by igniting. Compounds, hydroxides, sulfates, nitrates, carbonates, ammonium salts or mixtures thereof are used.

[0015]

EXAMPLES The effects of the present invention will be shown below with examples. "Parts" in Examples and Comparative Examples means parts by weight. The filling powder ratio (%) of the molded catalyst or the supported catalyst is defined as follows. That is, it is assumed that part b of the catalyst, which was filled from the upper part of the reactor vertically installed with respect to the horizontal direction of the catalyst a part and recovered from the bottom part of the container after filling, did not pass through the 14-mesh sieve. Filling powdering rate (%) = (ab / a) × 100

Example 1 A catalyst powder having the following composition was prepared. Mo ₁₂ W _0.1 Bi _0.9 Fe _1.2 Ni _0.5 Co ₄ Zn _0.1
Mg _0.5 B _0.2 Sb _0.3 K _0.06 Si ₅ O _x (in the formula, Mo, W, Bi, Fe, Ni, Co, Zn, M
g, B, Sb, K, Si and O are molybdenum,
Represents tungsten, bismuth, iron, nickel, cobalt, zinc, magnesium, boron, antimony, potassium, silicon and oxygen. The numbers in the lower right of the element symbols are the atomic ratios of each element, and x is the number of oxygen atoms required to satisfy the valence of each component (the same applies hereinafter). ) 970 parts of the obtained catalyst powder was thoroughly mixed with 30 parts of graphite powder, and then tablet-molded into a cylindrical shape having an outer diameter of 5 mm, an inner diameter of 2 mm and a height of 4 mm. Three wires having an outer diameter of 1 mm and a length of 5 m were inserted from the upper portion of a stainless steel cylindrical reactor having an inner diameter of 3 cm and a length of 5 m. 2 kg of the molded catalyst obtained above was dropped and filled from the upper part of the reactor. The filling powder ratio at this time was measured and found to be 0.9%.

Comparative Example 1 The molded catalyst obtained in the same manner as in Example 1 was dropped and charged into the same reactor as in Example 1 without inserting a wire. The filling powder ratio at this time was measured to be 4.7%
Met.

Example 2 A catalyst powder having the following composition was prepared. Mo ₁₂ W _0.2 Bi ₁ Fe _1.1 Co _4.5 Mn _0.1 Tl _0.04
P _0.15 Si ₁₀ O _x (in the formula, Mo, W, Bi, Fe, Co, Mn, Tl,
P, Si and O are molybdenum, tungsten,
Bismuth, iron, cobalt, manganese, thallium, phosphorus,
Represents silicon and oxygen. ) After thoroughly mixing 970 parts of the obtained catalyst powder with 30 parts of graphite powder, the diameter was 5 m.
It was tablet-molded into a cylindrical shape of m and a height of 4 mm. Inner diameter 3 cm,
Width 1c from the top of the stainless steel cylindrical reactor with a length of 5 m
One nylon ribbon having a length of m and a length of 4.6 m was inserted.
2 kg of the molded catalyst obtained above was dropped and filled from the upper part of the reactor in a manner that the ribbon was pulled up to 15 cm above every 100 g. The filling powder ratio at this time was measured and found to be 0.5%.

Comparative Example 2 The molded catalyst obtained in the same manner as in Example 2 was dropped and packed in the same reactor as in Example 2 without inserting a ribbon. The filling powder ratio at this time was measured to be 2.4.
%Met.

Example 3 A catalyst powder having the following composition was prepared. Mo ₁₂ W _0.2 Bi ₁ Fe _0.9 Ni ₄ Zn _0.2 Pb _0.2 T
e _0.1 Se _0.01 K _0.04 Na _0.02 O _x (in the formula, Mo, W, Bi, Fe, Ni, Zn, Pb, T
e, Se, K, Na and O represent molybdenum, tungsten, bismuth, iron, nickel, zinc, lead, tellurium, selenium, potassium, sodium and oxygen, respectively. )
200 parts of the obtained catalyst powder was supported on 800 parts of a spherical alumina carrier having a diameter of 4 mm. From the upper portion of the stainless steel cylindrical reactor having an inner diameter of 3 cm and a length of 5 m, one wire having a diameter of 0.8 mm and a length of 4.8 m, which was made of wool and provided with brush hair having a length of 1 cm, was inserted. 2 kg of the supported catalyst obtained above is
Every time it was filled with 00 g, the wire with brush bristles was dropped from the upper part of the reactor in a manner of pulling it up to 15 cm. The filling powder ratio at this time was measured and found to be 0.2%.

Comparative Example 3 The supported catalyst obtained in the same manner as in Example 3 was dropped and filled in the same reactor as in Example 3 as it was without inserting a wire with brush bristles. The filling powder ratio at this time was measured and found to be 1.2%.

Example 4 A catalyst powder having the following composition was prepared. Mo ₁₂ Bi _1.1 Fe ₁ Co ₄ Zn _0.5 Sn _0.5 S _0.03 G
e _0.1 Sb _0.1 Cs _0.02 Rb _0.02 O _X (in the formula, Mo, Bi, Fe, Co, Zn, Sn, S, G
e, Sb, Cs, Rb and O represent molybdenum, bismuth, iron, cobalt, zinc, tin, sulfur, germanium, antimony, cesium, rubidium and oxygen, respectively. ) A small amount of water was added to the obtained catalyst powder, mixed well, and then molded into a cylindrical shape having a diameter of 4 mm and a height of 5 mm by an extruder. From the upper part of the stainless steel cylindrical reactor having an inner diameter of 3 cm and a length of 5 m, 2 tubes of polytetrafluoroethylene having an outer diameter of 6 mm, an inner diameter of 3 mm and a length of 4.8 m were provided.
I inserted a book. 2 kg of the molded catalyst obtained above is mixed with 100
Each time g was charged, the tube was dropped from the upper part of the reactor in such a manner that the tube was pulled up to 15 cm above. The filling powder ratio at this time was measured and found to be 0.5%.

Comparative Example 4 A molded catalyst obtained in the same manner as in Example 4 was dropped and charged into the same reactor as in Example 4 without inserting a polytetrafluoroethylene tube. The filling powder ratio at this time was measured and found to be 1.9%.

Example 5 A catalyst powder having the following composition was prepared. Mo ₁₂ Bi ₁ Fe ₁ Co ₄ K _0.05 O _x (wherein Mo, Bi, Fe, Co, K and O represent molybdenum, bismuth, iron, cobalt, potassium and oxygen, respectively). After adding a small amount of water and mixing well, use an extruder to make an outer diameter of 5 mm and an inner diameter of 2 m.
m and a height of 3 mm were formed into a cylindrical shape. 8m in width from the upper part of the stainless steel cylindrical reactor with an inner diameter of 3cm and a length of 5m
Two resin chains having a length of m and a length of 4.9 m were inserted. 2 kg of the molded catalyst obtained above was dropped and filled from the upper part of the reactor in such a manner that the resin chain was pulled up to 15 cm above every 100 g. The filling powder ratio at this time was measured and found to be 0.6%.

Comparative Example 5 The molded catalyst obtained in the same manner as in Example 5 was dropped and packed in the same reactor as in Example 5 without inserting a resin chain. The filling powder ratio at this time was measured.
It was 3%.

[0026]

EFFECTS OF THE INVENTION When a fixed bed reactor is filled with a molded catalyst for acrolein and acrylic acid synthesis or a supported catalyst by the method of the present invention, pulverization of the catalyst due to physical impact during dropping
Collapse is significantly reduced. Therefore, it is not necessary to excessively increase the mechanical strength of the catalyst because of concern about powdering of the catalyst during filling. Therefore, restrictions on catalyst design are reduced, and catalyst preparation under a wide range of conditions becomes possible.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Ohkita 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory

Claims (2)

[Claims] 1. When a molded catalyst or a supported catalyst for synthesizing acrolein and acrylic acid by vapor-phase catalytic oxidation of propylene with molecular oxygen is dropped into a fixed-bed reactor from above, the reaction is substantially performed in the reactor. A method for filling a catalyst for synthesizing acrolein and acrylic acid, characterized in that at least one string-like substance having a shape and a thickness that does not hinder the catalyst from falling is interposed. 2. A molded catalyst or a supported catalyst having a general formula of Mo _a Bi _b Fe _c A _d X _e Y _f Z _g Si _h O _i (wherein Mo, Bi, Fe, Si and O are molybdenum, bismuth, Represents iron, silicon and oxygen, A is nickel and / or cobalt, X is magnesium, zinc,
At least one element selected from the group consisting of manganese, tin and lead, Y is at least one element selected from the group consisting of phosphorus, boron, sulfur, tellurium, selenium, germanium, tungsten and antimony, and Z is At least one element selected from the group consisting of potassium, sodium, rubidium, cesium and thallium is shown. However, a, b, c, d, e, f, g, h, and i represent the atomic ratio of each element, and when a = 12, 0.01 ≦ b ≦ 3,
0.01 ≦ c ≦ 5, 1 ≦ d ≦ 12, 0 ≦ e ≦ 5, 0 ≦ f
≦ 5, 0.001 ≦ g ≦ 1, 0 ≦ h ≦ 20, and i is the number of oxygen atoms required to satisfy the valence of each component. ) The method of packing a catalyst according to claim 1, wherein the method has a composition shown in FIG.