Spring structure and tube nest comprising same
By designing an integrated elastic element in a tubular fixed-bed reactor and utilizing an inert medium to deposit sublimated components, the problems of high-boiling-point organic component deposition and spring cleaning difficulties were solved, achieving long catalyst life and efficient operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LANZHOU YANGANG CHEMICAL CO LTD
- Filing Date
- 2025-04-23
- Publication Date
- 2026-05-08
AI Technical Summary
In a tubular fixed-bed reactor for the oxidation of propylene to acrolein, the deposition of high-boiling-point organic components at the temperature difference interface leads to increased bed resistance, loss of active catalyst components, and difficulty in cleaning or replacing traditional springs, thus affecting catalyst life and operating energy consumption.
Design an integrated elastic element, including a first spring and a second spring, with an inert medium inside, connected by a reduced diameter section, which facilitates the removal and cleaning of the spring, reduces the difficulty of operation, and utilizes the inert medium to deposit sublimation components, thereby reducing the pressure drop of the bed.
It effectively controls coking, extends catalyst life, reduces operational difficulty, improves catalyst utilization, and optimizes production process conditions.
Smart Images
Figure CN224207978U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of packed tubular fixed-bed reactors, and more particularly to a spring structure and a tubular structure comprising the spring structure. Background Technology
[0002] In the process of propylene oxidation to acrolein, the Bi2O3-MoO3 catalyst exhibits the highest activity and best selectivity. It comprises octahedral molybdate ions [MoO6] with Mo=O bonds. However, when MoO3 contacts propylene at 300-500℃, it readily combines with water vapor under the influence of high-temperature steam, sublimating as MoO3-nH2O, leading to a decrease in catalyst activity. In other words, from the perspective of the catalyst components themselves, there is a phenomenon of component loss due to the sublimation of active components.
[0003] The conventional reactor for the oxidation of propylene to acrolein is a tubular fixed-bed three-tube sheet reactor. Different active catalysts are packed along the inlet to outlet of the reaction tubes, with only a supporting spring at the bottom. The three tube sheets are an upper tube sheet, a middle tube sheet, and a lower tube sheet. The middle tube sheet, located in the lower part of the reactor, divides the reactor into two independent spaces: the upper part is the reaction section, and the lower part is the cooling section. This section is used to promptly remove the heat generated in the reaction section, preventing deep oxidation of the product and the formation of byproducts. The temperature difference between the reaction section and the cooling section is 80-110℃. Due to this relatively large temperature difference, high-boiling-point organic components in the reaction products are prone to deposit at the interface between the reaction and cooling sections. These high-boiling-point organic components have high viscosity and slow flow, creating a "seed effect" that hinders the normal flow of material and lost active components in the tubes. This leads to a continuous increase in bed resistance (pressure drop), resulting in a continuous increase in the overall operating energy consumption of the unit, a gradual deterioration of the catalyst's reactivity, a significant shortening of its service life, and seriously affecting the long-term stable operation of the catalyst.
[0004] Regarding the aforementioned technologies, the inventors believe that it is difficult to eliminate the metal impurities accumulated on one side of the catalyst using traditional coking methods. If physical methods are used for local coking removal, traditional catalysts are usually equipped with springs inside the tubes during loading. However, when coking occurs inside the tubes, the internal springs are difficult to remove for cleaning or replacement, leading to significant difficulties in subsequent operations. Utility Model Content
[0005] To facilitate the removal of the spring located inside the tube, reduce the need for subsequent cleaning or replacement of the spring, and lower the difficulty of subsequent operations, this application provides a spring structure and a tube containing the spring structure.
[0006] The spring structure provided in this application adopts the following technical solution:
[0007] A spring structure includes an integrated elastic element located inside a tubular fixed-bed reactor. The integrated elastic element includes a first spring and a second spring that are fixedly connected to each other. The second spring is located at the bottom end of the first spring and extends from the bottom end of the tubular fixed-bed reactor. The interior of the first spring is filled with an inert medium.
[0008] Optionally, a third spring is provided above the first spring, and the third spring is located at the junction of the reaction section and the quenching section of the tubular fixed bed reactor.
[0009] Optionally, a reduced diameter section is provided between the first spring and the second spring. The diameter of the reduced diameter section gradually increases from the center position toward both ends. One end of the reduced diameter section is fixedly connected to the first spring, and the other end of the reduced diameter section is fixedly connected to the second spring.
[0010] Optionally, the minimum inner diameter of the reduced diameter section is greater than 0, and the interior of the first spring and the interior of the second spring are connected through the reduced diameter section.
[0011] Optionally, the pitch of the reduced diameter section is smaller than the pitch of the first spring.
[0012] Optionally, the maximum outer diameter of the first spring is not greater than the inner diameter of the tubular fixed-bed reactor.
[0013] Optionally, the outer diameter of the first spring is 0.8-1 times the inner diameter of the tubular fixed-bed reactor.
[0014] Optionally, the outer diameter of the second spring is larger than the inner diameter of the tubular fixed-bed reactor.
[0015] Optionally, the first spring and the second spring have the same shape as the tubular fixed bed reactor, but the size of the first spring is smaller than the size of the tubular fixed bed reactor.
[0016] A tubular reactor comprising the aforementioned spring structure disposed within a tubular fixed-bed reactor.
[0017] In summary, this application includes at least one of the following beneficial technical effects:
[0018] 1. By installing a first spring and a second spring on a tubular fixed-bed reactor, with the first spring located in the quenching section region of the reactor, and because the first spring contains an inert medium, as the reaction continues, sublimated metal elements easily deposit on the surface of the inert medium with the high-temperature steam, causing bed blockage and a continuous increase in pressure drop, the first spring becomes stuck inside the tubular fixed-bed reactor and cannot be removed. By setting a narrowing section between the first spring and the second spring, with the top of the narrowing section fixedly connected to the first spring and the bottom of the narrowing section fixedly connected to the second spring, and the second spring extending from the bottom of the tubular fixed-bed reactor, the first spring can be removed from the inside of the tubular fixed-bed reactor by pulling the second spring through the narrowing section. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a spring structure and the overall structure of a tube containing the spring structure in an embodiment of this application.
[0020] Figure 2 This is a cross-sectional view of a spring structure and a tube containing the spring structure according to an embodiment of this application.
[0021] Figure 3 This is a schematic diagram of a spring structure and a first spring and a second spring in a tube containing the spring structure, according to an embodiment of this application.
[0022] Explanation of reference numerals in the attached drawings: 1. Integrated elastic element; 11. First spring; 12. Second spring; 13. Reduced diameter section; 2. Tubular fixed bed reactor; 21. Tube. Detailed Implementation
[0023] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0024] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.
[0025] In the process of propylene oxidation to acrolein, the Bi2O3-MoO3 catalyst exhibits the highest activity and best selectivity. It comprises octahedral molybdate ions [MoO6] with Mo=O bonds. However, when MoO3 contacts propylene at 300-500℃, it readily combines with water vapor under the influence of high-temperature steam, sublimating as MoO3-nH2O, leading to a decrease in catalyst activity. In other words, from the perspective of the catalyst components themselves, there is a phenomenon of component loss due to the sublimation of active components.
[0026] The conventional reactor for the oxidation of propylene to acrolein is a tubular fixed-bed three-tube sheet reactor. Different active catalysts are packed along the inlet to outlet of the reaction tubes, with only a supporting spring at the bottom. The three tube sheets are an upper tube sheet, a middle tube sheet, and a lower tube sheet. The middle tube sheet, located in the lower part of the reactor, divides the reactor into two independent spaces: the upper part is the reaction section, and the lower part is the cooling section. This section is used to promptly remove the heat generated in the reaction section, preventing deep oxidation of the product and the formation of byproducts. The temperature difference between the reaction section and the cooling section is 80-110℃. Due to this relatively large temperature difference, high-boiling-point organic components in the reaction products are prone to deposit at the interface between the reaction and cooling sections. These high-boiling-point organic components have high viscosity and slow flow, creating a "seed effect" that hinders the normal flow of material and lost active components in the tubes. This leads to a continuous increase in bed resistance (pressure drop), resulting in a continuous increase in the overall operating energy consumption of the unit, a gradual deterioration of the catalyst's reactivity, a significant shortening of its service life, and seriously affecting the long-term stable operation of the catalyst.
[0027] Regarding the aforementioned technologies, the inventors believe that it is difficult to eliminate the metal impurities accumulated on one side of the catalyst using traditional coking methods. If physical methods are used for local coking removal, traditional catalysts are usually equipped with springs inside the tubes during loading. However, when coking occurs inside the tubes, the internal springs are difficult to remove for cleaning or replacement, leading to significant difficulties in subsequent operations.
[0028] To facilitate the removal of the spring located inside the tube, reduce the need for subsequent cleaning or replacement of the spring, and lower the difficulty of subsequent operations, this application provides a spring structure and a tube containing the spring structure.
[0029] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.
[0030] This application discloses a spring structure. (Refer to...) Figure 1 , Figure 2 A spring structure includes an integrated elastic element 1 located inside a tubular fixed-bed reactor 2. The integrated elastic element 1 is a deformable structure, which allows the integrated elastic element 1 to adapt to the internal structure of the tubular fixed-bed reactor 2.
[0031] The integrated elastic element 1, located inside the tubular fixed-bed reactor 2, effectively controls coking in the reaction section and quenching section of the reactor, suppressing the continuous increase in catalyst bed pressure drop and facilitating rapid cleaning of the coking area. At the same time, the use of the spring assembly improves catalyst utilization, extends catalyst replacement cycle, and optimizes the process operating conditions of the production unit.
[0032] The integrated elastic component 1 includes a first spring 11 located inside the tubular fixed-bed reactor 2. The first spring 11 is coaxially arranged with the tubular fixed-bed reactor 2, and a second spring 12 is also provided at the bottom end of the first spring 11. The first spring 11 and the second spring 12 are both tubular in shape and have the same diameter. A reduced-diameter section 13 is provided between the first spring 11 and the second spring 12, which fixes the first spring 11 and the second spring 12 together. The shapes of the first spring 11 and the second spring 12 are the same as those of the tubular fixed-bed reactor 2, but the size of the first spring 11 is smaller than that of the tubular fixed-bed reactor 2.
[0033] Reference Figure 2 , Figure 3 The reduced diameter section 13 has a helical structure, and the direction of rotation of the reduced diameter section 13 is the same as that of the first spring 11 and the second spring 12. The top end of the reduced diameter section 13 is coaxial with and fixedly connected to the first spring 11, and the helix at the top end of the reduced diameter section 13 connects with the helix at the bottom end of the first spring 11. The bottom end of the reduced diameter section 13 is coaxial with and fixedly connected to the second spring 12, and the helix at the bottom end of the reduced diameter section 13 connects with the helix at the top end of the second spring 12.
[0034] The outer diameter of the reduced diameter section 13 gradually increases from the center to both ends, and the diameter at the point where the top of the reduced diameter section 13 connects with the first spring 11 is the same as the diameter at the point where the bottom of the first spring 11 connects with the reduced diameter section 13. The diameter at the point where the bottom of the reduced diameter section 13 connects with the second spring 12 is the same as the diameter at the point where the top of the second spring 12 connects with the reduced diameter section 13.
[0035] The distance between the minimum diameter position of the narrowed section 13 and the bottom end of the first spring 11 is the same as the distance between the minimum diameter position of the narrowed section 13 and the top end of the second spring 12. The minimum diameter of the narrowed section 13 is greater than 0, which allows space in the inner diameter at the minimum diameter position of the narrowed section 13, enabling relative communication between the interior of the first spring 11 and the interior of the second spring 12, facilitating the flow of the medium inside the tubular fixed bed reactor 2.
[0036] The pitch of the first spring 11 is the same as the pitch of the second spring 12, and the pitch of the reduced diameter section 13 is smaller than the pitch of the first spring 11.
[0037] The external structure of the integrated elastic element 1 is adapted to the internal structure of the tubular fixed-bed reactor 2. In some embodiments, the internal structure of the tubular fixed-bed reactor 2 is a tubular columnar structure, and the integrated elastic element 1 is a cylindrical structure adapted to it.
[0038] The diameter of the first spring 11 is not greater than the inner diameter of the tubular fixed-bed reactor 2. In some embodiments, the diameter of the first spring 11 is 0.8-1 times the inner diameter of the tubular fixed-bed reactor 2. The diameter of the second spring 12 is greater than the inner diameter of the tubular fixed-bed reactor 2, and the second spring 12 supports the first spring 11. The second spring 12 is located outside the bottom end of the tubular fixed-bed reactor 2, and is engaged with the bottom sidewall of the tubular fixed-bed reactor 2 by a narrowing section 13 located above the second spring 12.
[0039] The second spring 12 supports the upper narrowing section 13 and the first spring 11. The second spring 12 is located on the outside of the tubular fixed bed reactor 2, which makes it easy for the operator to remove the entire spring structure through the second spring 12, reducing the difficulty of removing the first spring 11 inside the tubular fixed bed reactor 2 due to coking.
[0040] In some embodiments, a third spring is also provided at the top of the first spring 11. The diameter of the third spring is the same as that of the first spring 11, and the third spring is located inside the tubular fixed bed reactor 2. The third spring is located at the junction of the reaction section and the quenching section in the tubular reactor 21.
[0041] The third spring ensures that the reaction products pass through the catalyst bed quickly and efficiently. By changing the flow pattern of the airflow, it blocks the accumulation of heat and obstructs the original flow path of the airflow, causing the airflow to redistribute briefly. This reduces the residence time and the accumulation of lost components at the bottom of the catalyst.
[0042] The first spring 11 is located in the quenching section of the tubular fixed-bed reactor 2, and an inert medium is placed inside it. In some embodiments, the inert medium may be ceramic balls and / or magnetic rings. As the reaction proceeds, sublimated catalyst components are easily deposited on the surface of the inert medium with the high-temperature steam, causing the bed pressure drop to rise continuously. However, placing the inert medium in the first spring 11 allows for easy replacement without affecting the catalyst bed, thus significantly optimizing the operating process.
[0043] This application also discloses a tubular fixed bed reactor 2 with a tubular tube 21. The tubular tube 21 includes the spring structure disposed inside the tubular tube 21 as described above. The first spring 11 is disposed inside the tubular tube 21, and the reduced diameter section 13 is located at the bottom end of the first spring 11. The lower part of the reduced diameter section 13 is engaged with the bottom end wall of the tubular tube 21. The second spring 12 is located outside the tubular tube 21 and is used to support the first spring 11.
[0044] In this application, the term "multiple" refers to at least two or more, unless otherwise expressly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0045] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
Claims
1. A spring structure, characterized in that: The device includes an integrated elastic element (1) located inside the tubular fixed bed reactor (2). The integrated elastic element (1) includes a first spring (11) and a second spring (12) that are fixedly connected to each other. The second spring (12) is located at the bottom end of the first spring (11) and extends from the bottom end of the tubular fixed bed reactor (2). The interior of the first spring (11) is filled with an inert medium.
2. The spring structure according to claim 1, characterized in that: A third spring is provided above the first spring (11), and the third spring is located at the junction of the reaction section and the quenching section of the tubular fixed bed reactor (2).
3. The spring structure according to claim 1, characterized in that: A reduced diameter section (13) is provided between the first spring (11) and the second spring (12). The diameter of the reduced diameter section (13) gradually increases from the center position toward both ends. One end of the reduced diameter section (13) is fixedly connected to the first spring (11), and the other end of the reduced diameter section (13) is fixedly connected to the second spring (12).
4. The spring structure according to claim 3, characterized in that: The minimum inner diameter of the reduced diameter section (13) is greater than 0, and the interior of the first spring (11) and the interior of the second spring (12) are connected through the reduced diameter section (13).
5. The spring structure according to claim 3, characterized in that: The pitch of the reduced diameter section (13) is smaller than the pitch of the first spring (11).
6. The spring structure according to claim 1, characterized in that: The maximum outer diameter of the first spring (11) is not greater than the inner diameter of the tubular fixed bed reactor (2).
7. The spring structure according to claim 6, characterized in that: The outer diameter of the first spring (11) is 0.8-1 times the inner diameter of the tubular fixed bed reactor (2).
8. The spring structure according to claim 1, characterized in that: The outer diameter of the second spring (12) is larger than the inner diameter of the tubular fixed bed reactor (2).
9. The spring structure according to claim 1, characterized in that: The first spring (11) and the second spring (12) have the same shape as the tubular fixed bed reactor (2), and the size of the first spring (11) is smaller than the size of the tubular fixed bed reactor (2).
10. A tube array (21), characterized in that: The tube (21) includes the spring structure according to any one of claims 1-9 disposed in the tube-type fixed bed reactor (2).