JPH09141084A - Packing method of solid catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress powdering or rupture of a solid catalyst to the min. when a solid catalyst is dropped from an upper part of a reaction tube to pack the reaction tube in a fixed bed reactor, by first supplying a liquid material to the reaction tube, packing the tube with the solid catalyst and then removing the liquid material. SOLUTION: In this multitube fixed bed reactor, lots of reaction tubes are arranged parallel to one another and are packed with a solid catalyst, and the source material for the reaction is passed through the tubes for the reaction. When the solid catalyst is dropped form the upper part of reaction tubes to pack the reactor tubes, first, a liquid material is supplied to fill the reaction tubes, then the solid catalyst is supplied and the liquid material is removed. Thereby, physical impact on the catalyst can be decreased and powdering and rupture of the catalyst can be largely suppressed. The liquid material is, preferably, alcohol and water. The amt. of the liquid to be supplied is about >=10vol% of the part of the reaction tube which is substantially to be packed with the catalyst.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for charging a solid bed reactor with a solid catalyst.

[0002]

2. Description of the Related Art Generally, when a solid catalyst is dropped and filled into a reaction tube installed in a fixed bed reactor from above, the catalyst is pulverized to some extent due to physical impact during the fall.
It may collapse. When the powdering / disintegration of the catalyst occurs at a significant rate, the reaction may not be able to be performed under the planned operating conditions due to a substantial decrease in the catalyst loading amount and / or an increase in the pressure loss. Generally, when packing a solid catalyst into a reaction tube in a fixed bed reactor, in order to suppress such pulverization and disintegration of the solid catalyst, the catalyst itself has a mechanical strength of a certain level or a packing. In many cases, some kind of ingenuity is applied to the method.

The mechanical strength of the catalyst is improved to some extent by adjusting the molding pressure when molding the catalyst and devising the molding operation. However, when the mechanical strength is increased by such a method, it becomes difficult to control the specific surface area and the pore distribution of the catalyst, and the yield of the target product is greatly reduced, and various sacrifices are inevitable.

In Japanese Patent Laid-Open No. 53131/1993, when a solid catalyst is filled in a reaction tube in a fixed bed reactor, a physical impact is alleviated by dropping the solid catalyst under the condition of interposing a string-like substance. A method for suppressing powdering / disintegration of syrup is disclosed. However, in a multi-tube reactor used industrially, there may be thousands or more of reaction tubes in some cases, and it is very complicated and practical to perform such work for each of them. It is hard to say that it is a simple method.

Therefore, from an industrial point of view, there is a demand for a simple filling method capable of suppressing the powdering and disintegration of the catalyst when dropping and filling the solid catalyst to the minimum.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a new packing method for packing a solid catalyst in a fixed bed reactor.

[0007]

According to the present invention, when a solid catalyst is dropped and filled from above into a reaction tube installed in a fixed bed reactor, the reaction tube is first filled with a liquid substance, and then the solid The gist of the method is to fill a solid catalyst, which comprises filling the catalyst and then removing the liquid material.

In the present invention, the fixed bed reactor refers to all those which are generally used industrially, but as mentioned above, the physical shock received by the catalyst when dropping the catalyst into the reaction tube is mitigated. However, from the viewpoint of the effect of greatly suppressing pulverization and disintegration of the catalyst, it is more effective when the length of the reaction tube is relatively long.

There is no particular limitation on the shape, size, etc. of the solid catalyst packed in the reaction tube in the fixed bed reactor used for carrying out the present invention, and it is usually spherical, cylindrical, ring-shaped, star-shaped, etc. What is molded by a tableting molding machine, an extrusion molding machine, a granulating machine, etc. are used. Further, a supported catalyst in which a catalytically active substance is supported on a carrier having the above shape may be used.

In the present invention, the liquid substance to be filled in the reaction tube in the fixed bed reactor prior to filling the catalyst is not particularly limited, but it is harmless to the target catalyst,
Do not extract the components of the target catalyst beyond the permissible range, have a low specific gravity that is low enough for the target catalyst to easily fall by gravity, and have a sufficiently low viscosity. Any substance can be used as long as it can be removed and the like, and alcohol and water are preferable from the industrial viewpoint.

In the present invention, the amount of the liquid material to be filled in the reaction tube in the fixed bed reactor prior to the filling of the catalyst is
It is preferably an amount corresponding to 10% by volume or more of the volume of the portion substantially filled with the catalyst in the reaction tube in the reactor. If the amount of this liquid is too small, the effect of mitigating the physical impact on the catalyst due to drop filling is small, and if the amount of this liquid is too large, when the catalyst is filled, the liquid is fixed bed. It is not preferable because it overflows from the upper part of the reactor. At this time, in terms of safety and the like, if the outflow of the liquid material is acceptable, if not, the amount of the liquid material is determined by the volume of the reaction tube in the fixed bed reactor and the volume of the catalyst to be charged. Or the liquid level is gradually removed to the outside of the fixed bed reactor in accordance with the progress of the catalyst packing, or the liquid surface is maintained within an appropriate range, or the fixed bed reaction is performed. This may be dealt with by a method such as devising the structure of the container so that the liquid substance can be safely discharged. In the present invention, since it is important to hold the liquid material in the fixed bed reactor at the time of filling the catalyst, the fixed bed reactor bottom is filled with the liquid material prior to the filling of the liquid material. It is necessary to devise a device that does not easily come out.

In carrying out the present invention, there is no particular limitation on the method of removing the liquid material after charging the catalyst, but the method of extracting only the liquid material from the bottom of the fixed bed reactor is the easiest and preferable. In addition to this, a method of sucking from the upper part of the reactor, a method of vaporizing and evaporating by heating, and the like can be mentioned. However, even in this case, it is important that the removal treatment does not adversely affect the catalyst.

[0013]

The present invention will be described below with reference to examples.

The reaction rate of isobutylene and the selectivity of methacrolein and methacrylic acid produced are defined as follows.

Reaction rate of isobutylene (%) = (number of moles of reacted isobutylene / number of moles of isobutylene fed) × 100 Methacrolein selectivity (%) = (number of moles of methacrolein formed / reacted of isobutylene Number of moles) x 10
0 Methacrylic acid selectivity (%) = (number of moles of methacrylic acid produced / number of moles of reacted isobutylene) × 100 Further, the packing pulverization rate of the catalyst is defined as follows. That is, the catalyst Xg was dropped and filled from the upper part of the reactor, and after the filling, the nominal size of the catalyst recovered from the bottom of the reactor was 1
It is assumed that Yg does not pass through the mm sieve.

Filling powdering rate (%) = {(X−Y) / X} × 100 Example 1 A catalyst powder having the following composition, which was a catalyst for methacrolein and methacrylic acid synthesis by oxidation of isobutylene, was prepared.

Mo ₁₂ Bi ₁ Fe _1.5 Co ₈ Zn _0.2 Cs _0.4
Sb _0.8 O _x (in the formula, Mo, Bi, Fe, Co, Zn, Cs, Sb and O are molybdenum, bismuth, iron, cobalt,
Represents zinc, cesium, antimony and oxygen. Also, the numbers in the lower right of the element symbols are the atomic ratios of the respective elements, and x is the number of oxygen atoms required to satisfy the valences of the respective components. ) 9800 g of the obtained catalyst powder was used as graphite powder 200
After mixing well with g, it was tablet-molded into a cylindrical shape having an outer diameter of 4 mm and a height of 4 mm.

Inner diameter 2 installed parallel to the vertical direction
7.5 mm, 4 m long stainless steel reaction tube (internal volume 2
376 ml), from the top, first, tertiary butanol 500
ml, and subsequently 2000 g of the above-mentioned molded catalyst (about 1
540 ml) was dropped and filled. Then, after removing the tertiary butanol from the bottom of the reaction tube, air was passed through the reaction tube overnight at room temperature.

Then, the temperature of the heat medium bath provided outside the reaction tube was set at 330 ° C., and isobutylene 5% and oxygen 12 were added.
%, Steam 10%, and nitrogen 73% as a raw material mixed gas was passed through the catalyst layer filled in the reaction tube at a contact time of 4.5 seconds. As a result, the reaction rate of isobutylene was 97.0.
%, The selectivity of methacrolein was 87.6%, and the selectivity of methacrylic acid was 5.3%. Moreover, the filling powder ratio was measured and found to be 0.1%.

Comparative Example 1 A catalyst was charged and a reaction was carried out in the same manner as in Example 1 except that the amount of the tertiary butanol charged in the reaction tube was 100 ml.

As a result, the reaction rate of isobutylene is 96.3.
%, The selectivity of methacrolein was 87.2%, and the selectivity of methacrylic acid was 5.2%, and the yields of methacrolein and methacrylic acid were slightly lowered. Moreover, the filling powder ratio was measured and found to be 2.2%.

Comparative Example 2 A catalyst was charged and a reaction was carried out in the same manner as in Example 1 except that the amount of the tertiary butanol charged in the reaction tube was 0 ml.

As a result, the reaction rate of isobutylene is 96.1.
%, The selectivity of methacrolein was 87.0%, the selectivity of methacrylic acid was 5.2%, and the yields of methacrolein and methacrylic acid were further reduced. Moreover, the filling powder ratio was measured and found to be 2.5%.

[0024]

When the solid catalyst is dropped and packed into the fixed bed reactor by the method according to the present invention, the physical impact on the catalyst is small, and therefore, the effect of significantly suppressing the pulverization and disintegration of the catalyst is obtained. To be Therefore, there is no need to excessively increase the mechanical strength of the catalyst due to concerns such as pulverization at the time of filling, and the restriction on catalyst design is reduced
There is also an effect that the catalyst can be prepared under a wide range of conditions.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // C07B 61/00 300 C07B 61/00 300

Claims (2)

[Claims] 1. When dropping and filling a solid catalyst into a reaction tube installed in a fixed bed reactor from above, first, a liquid material is filled in the reaction tube, and subsequently, the solid catalyst is filled, and then, A method for filling a solid catalyst, characterized in that the liquid material is removed. 2. The amount of the liquid material to be filled is 10% by volume of the volume of the portion substantially filled with the catalyst in the reaction tube.
The filling method according to claim 1, wherein the amount is equivalent to the above.