Method for filling reaction tubes with granular material
The method uses weights to detect and remove deposits in reaction tubes, ensuring uniform catalyst refilling by addressing non-uniform filling issues, enhancing efficiency and reducing time in the refilling process.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MITSUBISHI CHEM CORP
- Filing Date
- 2023-02-20
- Publication Date
- 2026-07-29
AI Technical Summary
Existing methods for refilling catalysts into fixed-bed multi-tubular reactors are hindered by deposits on the inner surface of reaction tubes, leading to non-uniform filling and inefficiencies.
A method involving the use of weights with specific dimensions and densities to detect and remove deposits within reaction tubes, followed by filling the tubes with granular material, ensuring uniform distribution.
Enables efficient and uniform filling of reaction tubes with granular material by effectively removing inner surface deposits, reducing the time required for the refilling process.
Smart Images
Figure 0007896512000001 
Figure 0007896512000002
Abstract
Description
Technical Field
[0001] The present invention relates to a method of filling particulate materials such as a catalyst into a plurality of reaction tubes, and is related to a method of filling particulate materials into a reaction tube that is employed, for example, when a new catalyst is refilled after extracting a used catalyst.
Background Art
[0002] In a process of performing a catalytic gas-phase reaction in the presence of a catalyst, such as a production process of an unsaturated aldehyde or an unsaturated carboxylic acid, a fixed-bed multi-tubular reactor is used.
[0003] As a method of refilling a catalyst into a fixed-bed multi-tubular reactor used in a catalytic gas-phase reaction in the presence of a catalyst, Patent Document 1 describes a method of filling a catalyst in which, when refilling a catalyst into a fixed-bed multi-tubular reactor, after extracting a used catalyst, the inner surface of the reaction tube is washed and then dried, and a new catalyst is refilled.
[0004] The inner surface of the reaction tube is smooth in the case of an unused reaction tube, but in the reaction tube after being used in a reaction and extracting a used catalyst, catalyst powder and reaction by-products may adhere, and the inner surface of the reaction tube may be roughened, which may inhibit uniform filling of the catalyst. Patent Document 1 attempts to uniformly refill the catalyst by washing and removing the deposits on the inner surface of this reaction tube.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] Even if the inner surface of the reaction tube is washed as in Patent Document 1, if deposits remain on the inner surface of the reaction tube, uniform filling of the catalyst is inhibited.
[0007] The present invention aims to provide a method for filling a reaction tube with granular material that can detect deposits that hinder uniform filling of the multi-tube reaction tube in a simple manner, and that can efficiently fill the reaction tube with granular material in a short time. [Means for solving the problem]
[0008] The present invention achieves the above objectives by the following method.
[0009] [1] A method of filling a plurality of reaction tubes having an inner diameter (D) arranged vertically with granular material, A method for filling reaction tubes with granular material, comprising dropping a weight made of a spherical object having a diameter of 0.90 to 0.99 times the inner diameter (D), or a cylindrical object having a diameter of 0.90 to 0.99 times the inner diameter (D), into a plurality of reaction tubes via a linear body, and then filling the tubes with granular material.
[0010] [2] The method for filling a reaction tube with granular material according to [1], wherein the plurality of reaction tubes are reaction tubes after the filled granular material has been discharged.
[0011] [3] The density of the spherical object is 7.0 g / cm³ 3 More than 9.8g / cm 3 A method for filling a reaction tube with granular material as described in [1] or [2] below.
[0012] [4] The density of the cylindrical object is 7.0 g / cm³ 3 More than 9.8g / cm 3 A method for filling a reaction tube with granular material as described in [1] or [2] below.
[0013] [5] A method for filling granular material into a reaction tube according to any one of [1] to [4], wherein the length of the plurality of reaction tubes is 2 to 10 m.
[0014] [6] A method for filling granular material into a reaction tube according to any one of [1] to [5], wherein the number of the plurality of reaction tubes is 5,000 to 80,000.
[0015] [7] The method for filling particulate matter into the reaction tubes according to any one of [1] to [6], wherein the plurality of reaction tubes are reaction tubes for producing unsaturated aldehyde.
[0016] [8] The method for filling particulate matter into the reaction tubes according to any one of [1] to [6], wherein the plurality of reaction tubes are reaction tubes for producing unsaturated carboxylic acid.
[0017] [9] The method for filling particulate matter into the reaction tubes according to any one of [1] to [8], wherein the reaction tubes are reaction tubes after discharging, cleaning, and drying the filled particulate matter.
[0018]
[10] Drop the weight into each reaction tube after cleaning and drying, fill the particulate matter into the reaction tube through which the weight has passed, For the reaction tubes through which the weight has not passed, perform cleaning and drying until the weight drops and passes through, and then fill with particulate matter. The method for filling particulate matter into the reaction tubes of [9]. [Advantages of the Invention]
[0019] According to the present invention, by dropping a weight into a reaction tube, checking for deposits on the inner surface of the reaction tube, and then filling with particulate matter, the filling operation of the particulate matter can be efficiently performed. [Brief Description of the Drawings]
[0020] <on000091>It is a schematic longitudinal sectional view of a fixed-bed multitubular reactor to which the method of the present invention can be applied. [Figure 2] It is a side view of the weight used in the examples. [Modes for Carrying Out the Invention]
[0021] Hereinafter, the present invention will be described in detail with reference to the drawings.
[0022] FIG. 1 is a schematic longitudinal sectional view of a fixed-bed multitubular reactor to which the method of the present invention can be preferably applied.
[0023] This fixed-bed multitube reactor 1 is equipped with multiple reaction tubes 2 filled with catalyst. The gas-phase catalytic reaction using this fixed-bed multitube reactor 1 is a reaction in which a predetermined starting compound is passed through the reaction tubes 2 filled with the catalyst and reacted to obtain the target compound.
[0024] The reaction tubes 2 are straight and installed vertically. The number of reaction tubes 2 is often 500 or more, particularly around 5,000 to 80,000. The length of the reaction tubes 2 is usually 2m or more, preferably 2 to 10m, and more preferably 2 to 6m.
[0025] In this embodiment, after removing the used catalyst from the reaction tube 2, the inner surface of the reaction tube 2 that came into contact with the catalyst is cleaned and dried. At this time, a gas such as air may be circulated into the reaction tube from the top or bottom to promote drying. The cleaning solution used to clean the inner surface of the reaction tube 2 is not particularly limited, but water is preferably used because it is readily available and can be used in large quantities. In particular, water with few impurities, such as re-cooled water or ion-exchanged water, is preferable. Alternatively, water containing alcohol or a conventionally known appropriate detergent may be used as the cleaning solution. If a detergent is used, rinse with purified water as necessary.
[0026] There are no particular restrictions on the method of cleaning the inner surface of reaction tube 2, but the top of the reactor A preferred method is to clean the reaction tube 2 by spraying high-pressure water (jet cleaning water) from the side or bottom.
[0027] In the method of this embodiment, the reaction tube 2 is washed and then dried as described above. Drying can be done by natural drying or drying with hot air, without any particular limitations.
[0028] In the catalyst packing method of this embodiment, after the washing and drying described above, a weight is suspended in the reaction tube 2 by a linear body and allowed to fall and move within the reaction tube 2 by its own weight. The linear body can be a thread-like material made of metal or synthetic resin, a rope, a chain, etc., but is not limited to this as long as it can suspend and hold the weight.
[0029] It is preferable to provide the weight body with hook-shaped parts for connecting the linear elements, or through holes for the linear elements.
[0030] As the cone, a spherical object having a diameter of 0.90 to 0.99 times the inner diameter (D) of the reaction tube 2, or a cylindrical object having a diameter (b) of 0.90 to 0.99 times the inner diameter (D) (see Figure 2) is used.
[0031] The density of the weight is 7.0 g / cm³ 3 More than 9.8g / cm 3 The following is preferable. The weight is preferably made of a metal such as stainless steel, but is not limited to this.
[0032] When the weight is cylindrical, it is preferable that the edges on the leading and trailing ends in the direction of fall are tapered.
[0033] Figure 2 is a side view of the weight used in the embodiment described later, where the periphery on the leading and trailing ends in the direction of fall is tapered. In Figure 2, the ratio of dimensions a / b is preferably 0.3 to 0.9, and more preferably 0.4 to 0.8. Also, the ratio c / d is preferably 0.0 to 0.99, and more preferably 0.3 to 0.7.
[0034] When the deposits on the inner surface of reaction tube 2 are sufficiently removed by the above cleaning process, the cone will smoothly fall and pass through the inside of reaction tube 2 from the top to the bottom. This confirms that the inner surface of reaction tube 2 is clean.
[0035] If the weight gets stuck during its descent and does not fall smoothly, or if its descent stops, it means that there is residue remaining on the inner surface of reaction tube 2. In this case, after removing the weight, the inside of reaction tube 2 should be washed and dried again. Then, the weight should be dropped again. Continue washing and drying the reaction tube until the weight falls and passes through smoothly.
[0036] After confirming that the cones fall and pass smoothly through all of the reaction tubes 2 in this manner, new catalyst is filled into the reaction tubes 2.
[0037] There are no particular limitations on the method for filling each reaction tube 2 with a new catalyst.
[0038] When filling each reaction tube 2 with new catalyst, it is preferable to fill the tube with catalyst so that a space remains at the top of the reaction tube 2.
[0039] According to this catalyst loading method of the present invention, even when used catalysts are removed from numerous reaction tubes of a fixed-bed multi-tube reactor and new catalysts are refilled, the catalyst loading operation can be carried out efficiently.
[0040] The present invention is suitable, but not limited to, a method for filling reaction tubes of a solid-bed multitubular reactor for the production of unsaturated aldehydes and unsaturated carboxylic acids with granular material. [Examples]
[0041] The present invention will be described in more detail below with reference to the following examples, but the present invention is not limited in any way to the following examples unless it exceeds the gist of the invention.
[0042] [Example 1] The multi-tube reactor had 27,000 cylindrical reaction tubes arranged vertically, each 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 sheet within the same circle. The granular material was discharged from all of the reaction tubes. The granular material contained a catalyst. The multi-tube reactor produced acrolein through the gas-phase catalytic oxidation reaction of propylene via the granular material for approximately four years.
[0043] After removing the granular material, the inside of all reaction tubes was washed with high-pressure water. Then, the inside of all reaction tubes was thoroughly dried with hot air, and the stainless steel ingots shown in Figure 2 (specific gravity 7.9 g / cm³) were put in. 3 A weight made of ) was dropped from the top of each reaction tube via a nylon thread, and the presence or absence of anything obstructing its descent was checked. The values were b / D = 24.4 / 25.4 = 0.96, a / b = 15.1 / 24.4 = 0.62, and c / d = 21.0 / 40.0 = 0.53.
[0044] Reaction tubes that had obstructions to the flow were cleaned and dried again with high-pressure water, and then checked for any obstructions until no obstructions remained. This process, carried out by 16 people, took approximately 5 hours.
[0045] Following this operation, 16 people carried out the task of filling all reaction tubes with granular material. After the filling of the granular material was completed, a measuring tape was inserted into each of the 27,000 reaction tubes from the upper tube sheet, and the position of the measuring tape at the point where the tip of the tape reached the top surface of the filled granular material was checked to confirm whether the target packed bed height had been reached.
[0046] Upon checking, 161 reaction tubes were found to have not reached the target packed bed height. For reaction tubes that had not reached the target packed bed height, the granular material was discharged from the reaction tube, and the granular material was refilled into the reaction tube. The filling height was then checked using the same method as above, and this process was repeated until the target packed bed height was reached. The filling process was considered complete when all reaction tubes were filled to the target packed bed height with granular material. It was estimated that the reasons for not reaching the target packed bed height were mainly due to careless mistakes such as forgetting to fill or double filling.
[0047] The number of working days required to discharge the granular material from all reaction tubes in the aforementioned multi-tube reactor, clean and dry all reaction tubes, and complete the refilling of the granular material was 12 days.
[0048] [Example 2] The multi-tube reactor, which consisted of 27,000 cylindrical reaction tubes arranged vertically, with an inner diameter D of 27.2 mm and a length of 3.3 m, and a structure in which both ends of the reaction tubes were attached to the tube sheet within the same circle, discharged the filled granular material from all reaction tubes. The granular material contained a catalyst. The multi-tube reactor had been producing acrylic acid for approximately four years through the gas-phase catalytic oxidation reaction of acrolein via the granular material.
[0049] After removing the granular material, the inside of all reaction tubes was washed with high-pressure water. Then, the inside of all reaction tubes was thoroughly dried with hot air, and the stainless steel ingots shown in Figure 2 (specific gravity 7.9 g / cm³) were added. 3 A weight made of ) was dropped from the top of each reaction tube via a nylon thread, and the presence or absence of anything obstructing its descent was checked. The values were b / D = 25.2 / 27.2 = 0.93, a / b = 15.6 / 25.2 = 0.62, and c / d = 20.4 / 40.0 = 0.51.
[0050] Reaction tubes that had obstructions to the flow were cleaned and dried again with high-pressure water, and then checked for any obstructions until no obstructions remained. This process, carried out by 16 people, took approximately 5 hours.
[0051] Following this procedure, 16 people carried out the granular material filling process for all reaction tubes. After the granular material filling was completed, a measuring tape was inserted into each of the 27,000 reaction tubes from the upper tube sheet. The position of the measuring tape at which the tip reached the top surface of the filled granules was checked to confirm whether the target packed bed height had been reached. As a result of the check, 206 reaction tubes had not reached the target packed bed height. For reaction tubes that had not reached the target packed bed height, the filled granular material was discharged from the reaction tube, and the granular material was refilled into the reaction tube. The filling height was checked in the same manner as above, and this process was repeated until the target packed bed height was reached. The filling process was considered complete when all reaction tubes were filled with granular material to the target packed bed height. It was estimated that the reasons for not reaching the target packed bed height were mainly due to careless mistakes such as forgetting to fill or double filling.
[0052] The number of working days required to discharge the granular material from all reaction tubes in the aforementioned multi-tube reactor, clean and dry all reaction tubes, and complete the refilling of the granular material was 8 days.
[0053] [Comparative Example 1] In Example 1, the procedure was the same as in Example 1, except that an internal surface check using a weight was not performed. Sixteen people performed the discharge of granular material, cleaning and drying of the reaction tubes, and refilling of the granular material, and checked whether the target packed bed height was reached. As a result, 529 reaction tubes did not reach the target packed bed height. While some of these failures were due to careless mistakes, it was presumed that the main cause was the presence of something in the reaction tube that hindered filling before the granular material was added.
[0054] For reaction tubes that have not reached the target packed bed height, the filled granular material is discharged from the reaction tube (if discharge is difficult, the granular material is removed from the reaction tube by scraping), the granular material is refilled into the reaction tube, the filling height is checked in the same manner as above, and this is repeated until the target packed bed height is reached, at which point the filling operation is completed.
[0055] The number of working days required to discharge the granular material from all reaction tubes in the aforementioned multi-tube reactor, clean and dry all reaction tubes, and complete the refilling of the granular material was 20 days.
[0056] [Comparative Example 2] In Example 2, the procedure was the same as in Example 2, except that an internal surface check using a weight was not performed. Sixteen people performed the discharge of granular material, cleaning and drying of the reaction tubes, and refilling of the granular material, and checked whether the target packed bed height was reached. As a result, 277 reaction tubes did not reach the target packed bed height. While some of these failures were due to careless mistakes, it was presumed that the main cause was the presence of something in the reaction tube that hindered filling before the granular material was added.
[0057] For reaction tubes that have not reached the target packed bed height, the filled granular material is discharged from the reaction tube (if discharge is difficult, the granular material is removed from the reaction tube by scraping), the granular material is refilled into the reaction tube, the filling height is checked in the same manner as above, and this is repeated until the target packed bed height is reached, at which point the filling operation is completed.
[0058] The number of working days required to discharge the granular material from all reaction tubes in the aforementioned multi-tube reactor, clean and dry all reaction tubes, and complete the refilling of the granular material was 15 days. [Explanation of Symbols]
[0059] 1. Fixed-bed multi-tube reactor 2 reaction tubes 3. Upper tube sheet 4. Lower tube sheet 6 Upper mirror part 7 Lower mirror part
Claims
1. A method for filling a plurality of reaction tubes having an inner diameter (D) arranged vertically with granular material, A method for filling reaction tubes with granular material, comprising dropping a weight made of a spherical object having a diameter of 0.90 to 0.99 times the inner diameter (D), or a cylindrical object having a diameter of 0.90 to 0.99 times the inner diameter (D), into a plurality of reaction tubes via a linear body, and then filling the tubes with granular material.
2. The method for filling granular material into reaction tubes according to claim 1, wherein the plurality of reaction tubes are reaction tubes after the filled granular material has been discharged.
3. The density of the aforementioned spherical object is 7.0 g / cm³ ３ 9.8g / cm or more ３ The method for filling a reaction tube with granular material according to claim 1, which is as follows:
4. The density of the cylindrical object is 7.0 g / cm³. ３ 9.8g / cm or more ３ The method for filling a reaction tube with granular material according to claim 1, which is as follows:
5. The method for filling granular material according to claim 1, wherein the length of the plurality of reaction tubes is 2 to 10 m.
6. The method for filling granular material into a reaction tube according to claim 1, wherein the number of the plurality of reaction tubes is 5,000 to 80,000.
7. The method for filling granular material into a reaction tube according to claim 1, wherein the plurality of reaction tubes are reaction tubes for producing unsaturated aldehydes.
8. The method for filling granular material into a reaction tube according to claim 1, wherein the plurality of reaction tubes are reaction tubes for producing unsaturated carboxylic acids.
9. The method for filling a reaction tube with granular material according to claim 1, wherein the reaction tube is a reaction tube after the filled granular material has been discharged, washed, and dried.
10. The weights are dropped into each reaction tube after washing and drying. The granular material is filled into the reaction tube through which the weight has passed. The method for filling reaction tubes with granular material according to claim 9, wherein, for reaction tubes through which the weight did not pass, the tubes are washed and dried until the weight falls and passes through, and then the granular material is filled into them.