JP2023129304A - Method for filling reaction tube with granule - Google Patents

Abstract

To provide a method for filling a reaction tube with granules which can detect a substance inhibiting uniform filling in a multi-tube type reaction tube by a simple method, and can efficiently fill the reaction tube with granules in short time.SOLUTION: A method for filling a reaction tube with granules, which fills a plurality of reactions tubes that are arranged in a vertical direction and have inner diameters (D) with granules, falls a weight body composed of a spherical object having a diameter of 0.90 time or more and 0.99 time or less of the inner diameter (D), or a columnar object having a diameter of 0.90 time or more and 0.99 time or less of the inner diameter (D) into the plurality of reaction tubes through a linear body, and then fills the reaction tubes with granules.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method of filling particulate matter such as a catalyst into a plurality of reaction tubes, such as when refilling a reaction tube with a new catalyst after extracting a used catalyst. Regarding the filling method.

Fixed-bed multitubular reactors are used in processes that carry out catalytic gas phase reactions in the presence of catalysts, such as processes for producing unsaturated aldehydes and unsaturated carboxylic acids.

As a method for refilling a solid bed multitubular reactor with a catalyst, Patent Document 1 describes a method for refilling a fixed bed multitubular reactor with a catalyst used in a catalytic gas phase reaction in the presence of a catalyst. In doing so, a catalyst filling method is described in which the inner surface of the reaction tube is washed and dried after removing the used catalyst, and then refilled with new catalyst.

The inner surface of the reaction tube is smooth when it is unused, but once the reaction tube has been used for a reaction and the used catalyst has been removed, catalyst powder and reaction by-products may adhere to the inside of the reaction tube. The surface may be rough, which may prevent uniform loading of the catalyst. Patent Document 1 attempts to refill the catalyst uniformly by cleaning and removing the deposits on the inner surface of the reaction tube.

Japanese Patent Application Publication No. 2006-159197

Even if the inner surface of the reaction tube is cleaned as in Patent Document 1, if deposits remain on the inner surface of the reaction tube, uniform filling of the catalyst is inhibited.

The present invention makes it possible to detect deposits that impede uniform filling in a multi-tubular reaction tube using a simple method, and to efficiently fill the reaction tube with particulate matter in a short time. The objective is to provide a filling method for

The present invention achieves the above object by the following method.

[1] A method of filling a plurality of vertically arranged reaction tubes having an inner diameter (D) with particulate matter,
Consisting of a spherical object having a diameter of 0.90 times or more and 0.99 times or less of the inner diameter (D), or a cylindrical object having a diameter of 0.90 times or more and 0.99 times or less of the inner diameter (D) A method for filling a reaction tube with particulate matter, which comprises dropping a weight body into the plurality of reaction tubes via a linear body, and then filling the reaction tube with particulate matter.

[2] The method for filling a reaction tube with particulate matter according to [1], wherein the plurality of reaction tubes are reaction tubes after discharging the filled particulate matter.

[3] The method for filling a reaction tube with a granular material according to [1] or [2], wherein the spherical material has a density of 7.0 g/cm ³ or more and 9.8 g/cm ³ or less.

[4] The method for filling a reaction tube with a granular material according to [1] or [2], wherein the cylindrical material has a density of 7.0 g/cm ³ or more and 9.8 g/cm ³ or less.

[5] The method of filling particulate matter into a reaction tube according to any one of [1] to [4], wherein the plurality of reaction tubes have a length of 2 to 10 m.

[6] The method for filling a reaction tube with granules according to any one of [1] to [5], wherein the number of the plurality of reaction tubes is 5,000 to 80,000.

[7] The method of filling particulate matter into a reaction tube according to any one of [1] to [6], wherein the plurality of reaction tubes are reaction tubes for producing an unsaturated aldehyde.

[8] The method for filling a reaction tube with particulate matter according to any one of [1] to [6], wherein the plurality of reaction tubes are reaction tubes for producing an unsaturated carboxylic acid.

[9] The method for filling a reaction tube with granules according to any one of [1] to [8], wherein the reaction tube is a reaction tube after the filled granules have been discharged, washed, and dried.

[10] Dropping the weight into each reaction tube after washing and drying,
Filling the reaction tube through which the weight passed, with the granular material,
The reaction tube through which the weight did not pass is washed and dried until the weight falls down and passes through, and then filled with particulate matter. Filling the reaction tube with particulate matter in [9] Method.

According to the present invention, by dropping the weight into the reaction tube and filling the reaction tube with the granules after confirming the presence or absence of deposits on the inner surface of the reaction tube, it is possible to efficiently perform the filling operation of the granules.

1 is a schematic longitudinal sectional view of a fixed bed multitubular reactor to which the method of the present invention can be applied. FIG. 3 is a side view of a weight body used in Examples.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic vertical sectional view of a fixed bed multitubular reactor to which the method of the present invention can be suitably applied.

This fixed bed multitubular reactor 1 includes a plurality of reaction tubes 2 filled with a catalyst. This gas phase catalytic reaction using the fixed bed multi-tubular reactor 1 is a reaction in which a target compound is obtained by reacting a predetermined raw material compound while passing it through the reaction tube 2 filled with the catalyst. be.

The reaction tube 2 has a straight tube shape and is installed vertically. The number of reaction tubes 2 is often 500 or more, particularly about 5,000 to 80,000. Further, the length of the reaction tube 2 is usually 2 m or more, preferably 2 to 10 m, and more preferably 2 to 6 m.

In this embodiment, after the used catalyst is extracted from the reaction tube 2, the inner surface of the reaction tube 2 that comes into contact with the catalyst is washed and dried. At this time, drying may be promoted by flowing gas such as air into the reaction tube from the upper or lower part of the reaction tube. The cleaning liquid used to clean the inner surface of the reaction tube 2 is not particularly limited, but water is preferably used because it is easily available and can be used in large quantities. In particular, water with few impurities such as re-chilled water or ion-exchanged water is preferable. Note that water containing alcohol or a conventionally known appropriate detergent may be used as the cleaning liquid. If detergent is used, rinse with clean water as necessary.

The method for cleaning the inner surface of the reaction tube 2 is not particularly limited, but a method of cleaning the reaction tube 2 by injecting high-pressure water (jet cleaning water) from the upper or lower part of the reactor is preferably used. .

In the method of this embodiment, the reaction tube 2 is washed and then dried as described above. For drying, natural drying, drying with hot air, etc. can be applied without particular restriction.

In the catalyst filling method of this embodiment, after the above-mentioned cleaning and drying are performed, a weight body is suspended in the reaction tube 2 by a linear body, and is allowed to fall and move within the reaction tube 2 by its own weight. The linear body may be a metal or synthetic resin filament, a rope, a chain, etc., but is not limited to this as long as it can hang and hold the weight body.

It is preferable that the weight body is provided with a hook-shaped portion for connecting the linear body, a through hole for the linear body, and the like.

The weight body may be a spherical object having a diameter of 0.90 times or more and 0.99 times or less of the inner diameter (D) of the reaction tube 2, or a spherical object with a diameter of 0.90 times or more and 0.99 times or less of the inner diameter (D). A cylindrical object having a diameter (b) (see Figure 2) is used.

The density of the weight body is preferably 7.0 g/cm ³ or more and 9.8 g/cm ³ or less. The weight body is preferably made of metal such as stainless steel, but is not limited thereto.

When the weight body is cylindrical, it is preferable that the peripheral edges on the leading end side and the rear end side in the falling direction are tapered.

FIG. 2 is a side view of a weight body used in an example described below, and the peripheral edges on the leading end side and the rear end side in the falling direction are tapered. The dimension ratio a/b in FIG. 2 is preferably 0.3 to 0.9, particularly 0.4 to 0.8. Further, c/d is preferably 0.0 to 0.99, particularly 0.3 to 0.7.

When the deposits on the inner surface of the reaction tube 2 have been sufficiently removed by the above cleaning, the weight falls smoothly and passes through the reaction tube 2 from the upper end to the lower end. This confirms that the inner surface of the reaction tube 2 is clean.

If the weight gets caught on the way down and does not fall smoothly, or if it stops falling, there may be some deposits left on the inner surface of the reaction tube 2. After pulling up the weight, remove the reaction tube. 2. Wash and dry the inside again. Next, try dropping the weight again. Wash and dry the reaction tube until the weight can fall smoothly and pass through.

After confirming that the weight bodies fall and pass smoothly through all the reaction tubes 2 in this manner, a new catalyst is filled into the reaction tubes 2.

The method of filling new catalyst into each reaction tube 2 is not particularly limited.

When filling each reaction tube 2 with a new catalyst, it is preferable to fill the reaction tube 2 with the catalyst so that a space remains in the upper part of the reaction tube 2.

According to the catalyst filling method of the present invention, even when a used catalyst is extracted from a large number of reaction tubes of a fixed bed multitubular reactor and new catalyst is refilled, the catalyst can be efficiently packed. It becomes possible to carry out filling work.

The present invention is suitable as a method for filling particulates into reaction tubes of a solid phase bed multitubular reactor for producing unsaturated aldehydes and unsaturated carboxylic acids, but is not limited thereto.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

[Example 1]
27,000 cylindrical reaction tubes arranged vertically, with an inner diameter D of 25.4 mm and a length of 3.8 m, and both ends of the reaction tubes were attached to the tube plate in the same circle. The filled granules were discharged from all reaction tubes of a multi-tubular reactor having a similar structure. The granules contain a catalyst. The multi-tubular reactor produced acrolein through the gas phase catalytic oxidation reaction of propylene through the granules for about 4 years.

After discharging the particulate matter, the inside of all reaction tubes was washed with high pressure water. Next, after sufficiently drying the inside of all reaction tubes with hot air, a weight body made of a stainless steel lump (specific gravity 7.9 g/cm ³ ) shown in FIG. 2 was inserted into each reaction tube through a nylon thread. We dropped it from above and checked to see if there was anything blocking it from falling. In addition, b/D=24.4/25.4=0.96, a/b=15.1/24.4=0.62, c/d=21.0/40.0=0.53. be.

For reaction tubes in which something was blocking the fall, the inside was washed again with high-pressure water and dried, and then the process of checking for the presence of anything blocking the fall was continued until there was nothing blocking the fall. The above work by 16 people took about 5 hours.

After this operation, 16 people filled all the reaction tubes with granules. After filling the granules, insert a tape measure into the reaction tubes from the upper tube plate for all 27,000 reaction tubes. The position was confirmed and it was checked whether the target packed bed height was reached.

As a result of checking, 161 reaction tubes did not reach the target packed bed height. For reaction tubes that have not reached the target packed bed height, discharge the filled granules from the reaction tube, fill the reaction tube with granules again, and check the filling height using the same method as above to reach the target. This process was repeated until the height of the packed bed was reached. The filling operation was completed when all reaction tubes were filled with granules to the target packed bed height. It is assumed that the reason for not reaching the above-mentioned target packed bed height was mainly due to careless mistakes such as forgetting to fill or double filling.

It took 12 days to discharge the filled granules from all reaction tubes in the multi-tubular reactor, wash and dry the insides of all reaction tubes, and complete refilling of the granules.

[Example 2]
27,000 cylindrical reaction tubes with an inner diameter D of 27.2 mm and a length of 3.3 m arranged in the vertical direction, and both ends of the reaction tubes were attached to the tube plate in the same circle. The filled granules were discharged from all reaction tubes of a multi-tubular reactor having a similar structure. The granules contain a catalyst. The multitubular reaction tube had been producing acrylic acid through the gas phase catalytic oxidation reaction of acrolein for about 4 years through the granules.

After extracting the particulate matter, the inside of all reaction tubes was washed with high pressure water. Next, after sufficiently drying the inside of all reaction tubes with hot air, a weight body made of a stainless steel lump (specific gravity 7.9 g/cm ³ ) shown in FIG. 2 was inserted into each reaction tube through a nylon thread. We dropped it from above and checked to see if there was anything blocking it from falling. In addition, b/D=25.2/27.2=0.93, a/b=15.6/25.2=0.62, c/d=20.4/40.0=0.51. be.

For reaction tubes in which something was blocking the fall, the inside was washed again with high-pressure water and dried, and then the process of checking for the presence of anything blocking the fall was continued until there was nothing blocking the fall. The above work by 16 people took about 5 hours.

After this operation, 16 people filled all the reaction tubes with granules. After filling the granules, insert a tape measure into the reaction tubes from the upper tube plate for all 27,000 reaction tubes, and when the tip of the tape reaches the top of the filled granules, the tape measure in The position was confirmed and it was checked whether the target packed bed height was reached. As a result of checking, 206 reaction tubes did not reach the target packed bed height. For reaction tubes that have not reached the target packed bed height, discharge the filled granules from the reaction tube, fill the reaction tube with granules again, check the filling height in the same manner as above, and then This process was repeated until the height of the packed bed was reached. The filling operation was completed when all reaction tubes were filled with granules to the target packed bed height. It is assumed that the reason for not reaching the above-mentioned target packed bed height was mainly due to careless mistakes such as forgetting to fill or double filling.

The number of working days required to discharge the filled granules from all reaction tubes in the multitubular reactor described above, wash and dry the insides of all reaction tubes, and complete refilling of the granules was 8 days.

[Comparative example 1]
In Example 1, 16 people discharged the particulate matter, washed the inside of the reaction tube, dried it, and refilled the particulate matter in the same manner as in Example 1, except that the inner surface was not checked using the weight body, and the target filling was achieved. I checked to see if it had reached the height. As a result, 529 reaction tubes did not reach the target packed bed height. Although some of the reaction tubes that did not reach the target packed bed height were due to careless mistakes, it is assumed that the main cause was that there was something in the reaction tube that was blocking the filling before filling with particulates. Ta.

For reaction tubes that have not reached the target packed bed height, the filled granules are discharged from the reaction tube (if it is difficult to discharge, the granules are removed from the reaction tube by scraping), and the granules are poured into the reaction tube again. The material was filled, the filling height was checked in the same manner as above, and this was repeated until the target filling bed height was reached, and the filling operation was completed.

It took 20 days to discharge the filled granules from all reaction tubes in the multi-tubular reactor, wash and dry the insides of all reaction tubes, and complete refilling of the granules.

[Comparative example 2]
In Example 2, 16 people discharged the particulate matter, washed the inside of the reaction tube, dried it, and refilled the particulate matter in the same manner as in Example 2, except that the inner surface was not checked using the weight body, and the target filling was achieved. I checked to see if it had reached the height. As a result, 277 reaction tubes did not reach the target packed bed height. Although some of the reaction tubes that did not reach the target packed bed height were due to careless mistakes, it is assumed that the main cause was that there was something in the reaction tube that was blocking the filling before filling with particulates. Ta.

For reaction tubes that have not reached the target packed bed height, the filled granules are discharged from the reaction tube (if it is difficult to discharge, the granules are removed from the reaction tube by scraping), and the granules are poured into the reaction tube again. The material was filled, the filling height was checked in the same manner as above, and this was repeated until the target filling bed height was reached, and the filling operation was completed.

It took 15 days to discharge the filled granules from all reaction tubes in the multi-tubular reactor, wash and dry the insides of all reaction tubes, and complete refilling of the granules.

1 Fixed bed multi-tubular reactor 2 Reaction tube 3 Upper tube sheet 4 Lower tube sheet 6 Upper mirror section 7 Lower mirror section

Claims (10)

A method of filling a plurality of vertically arranged reaction tubes having an inner diameter (D) with particulate matter,
Consisting of a spherical object having a diameter of 0.90 times or more and 0.99 times or less of the inner diameter (D), or a cylindrical object having a diameter of 0.90 times or more and 0.99 times or less of the inner diameter (D) A method for filling a reaction tube with particulate matter, which comprises dropping a weight body into the plurality of reaction tubes via a linear body, and then filling the reaction tube with particulate matter. 2. The method for filling a reaction tube with granules according to claim 1, wherein the plurality of reaction tubes are reaction tubes after the filled granules have been discharged. The method for filling a reaction tube with a granular material according to claim 1, wherein the density of the spherical material is 7.0 g/cm ³ or more and 9.8 g/cm ³ or less. The method for filling a reaction tube with particulate matter according to claim 1, wherein the density of the columnar material is 7.0 g/cm ³ or more and 9.8 g/cm ³ or less. The method for filling particulate matter according to claim 1, wherein the length of the plurality of reaction tubes is 2 to 10 m. The method for filling a reaction tube with particulate matter according to claim 1, wherein the number of the plurality of reaction tubes is 5,000 to 80,000. The method for filling a reaction tube with particulate matter according to claim 1, wherein the plurality of reaction tubes are reaction tubes for producing an unsaturated aldehyde. The method for filling a reaction tube with particulate matter according to claim 1, wherein the plurality of reaction tubes are reaction tubes for producing an unsaturated carboxylic acid. 2. The method for filling a reaction tube with granules according to claim 1, wherein the reaction tube is a reaction tube after the filled granules have been discharged, washed, and dried. Dropping the weight into each reaction tube after washing and drying,
Filling the reaction tube through which the weight passed, with the granular material,
Filling the reaction tube with particulate matter according to claim 9, wherein the reaction tube through which the weight body did not pass is washed and dried until the weight body falls and passes through, and then is filled with particulate matter. Method.

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