Reactor for preparing aminocapronitrile from caprolactam

Abstract

The utility model relates to the field of chemical industry, in particular to a reactor for preparing aminocapronitrile from caprolactam, which comprises a reactor shell, a reaction tube plate is arranged in the shell and is formed by alternately arranging process medium cavities and thermal medium cavities, the thermal medium cavities are closed cavities, one end of each thermal medium cavity is connected with a heating medium inlet pipe, and the other end of each thermal medium cavity is connected with a heating medium outlet pipe. The other end is connected with a heating medium outlet pipe; the process medium cavity is of a structure with the upper end and the lower end open, a bottom net is arranged at the lower end, and the process medium cavity is filled with a catalyst. According to the utility model, the process medium cavities and the thermal medium cavities are alternately arranged, so that under the condition of ensuring the filling amount of the catalyst, the requirement on the heat of the reaction for preparing aminocapronitrile from caprolactam can be met, the temperature difference of the catalyst is reduced, and the selectivity of the reaction is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of fine chemical industry and relates to a reactor for preparing aminocapronitrile from caprolactam. Background Art

[0002] The production of aminocapronitrile from caprolactam is a process currently under development in China for producing hexamethylenediamine and, subsequently, nylon 6,6. The reaction temperature is high, requiring the process medium to be heated to 300-350°C throughout the entire process. The reaction is endothermic. Heat transfer is crucial to the heat requirements of the reaction. Heat transfer is dependent on the temperature difference, the catalyst's thermal conductivity, and the catalyst's radial transfer thickness. Given a given reaction heat requirement, the catalyst's thermal conductivity is fixed. A greater temperature difference and a smaller catalyst's radial transfer thickness increase the heat supply. Generally speaking, reaction temperature is crucial for chemical reactions. The higher the temperature consistency of the catalyst bed throughout the reaction, the higher the selectivity and the lower the number of byproducts. Therefore, while ensuring the catalyst loading, a higher temperature consistency in the catalyst bed (i.e., a smaller catalyst temperature difference) facilitates the reaction. Summary of the Invention

[0003] The utility model provides a caprolactam to aminocapronitrile reactor, which alternately arranges process medium cavities and heat medium cavities, thereby ensuring the catalyst loading amount while meeting the heat demand for the caprolactam to aminocapronitrile reaction, reducing the catalyst temperature difference and improving the reaction selectivity.

[0004] The technical solution of the utility model is to provide a caprolactam to aminocapronitrile reactor, comprising a reactor shell, a reaction tube plate arranged in the shell, the reaction tube plate being composed of process medium cavities and heat medium cavities arranged alternately, the heat medium cavity being a closed cavity, one end of the heat medium cavity being connected to a heating medium inlet pipe, and the other end being connected to a heating medium outlet pipe; the process medium cavity being a structure with an upper end and a lower end being open, a bottom net being provided at the lower end, and a catalyst being filled in the process medium cavity.

[0005] Optionally, a sealing plate is provided between the edge of the reaction tube plate and the inner wall of the shell, and the sealing plate divides the reactor into independent spaces.

[0006] Optionally, the sealing plate is provided with at least two layers, one layer is located between the top edge of the reaction tube plate and the inner wall of the shell; the other layer is located between the bottom edge of the reaction tube plate and the inner wall of the shell.

[0007] Optionally, the sealing plate is provided with a through hole, and an air inlet pipe is connected to the shell between the two sealing plates.

[0008] Optionally, the diameter of the through hole is 5 mm-20 mm.

[0009] Optionally, the width between the process medium cavities is 5 mm-50 mm.

[0010] Optionally, there are multiple heat medium cavities, each heat medium cavity is connected to the heating medium inlet pipe via a heating medium inlet branch pipe; each heat medium cavity is connected to the heating medium outlet pipe via a heating medium outlet branch pipe.

[0011] The utility model has the following beneficial effects:

[0012] In the reactor provided by the utility model, the gaseous phase of caprolactam and ammonia is mixed and then enters the reactor, and then enters the process medium cavity to react with the catalyst. Since the heat medium cavity and the process medium cavity are alternately arranged, the heat in the heat medium cavity can be quickly transferred to the process medium cavity, heating the reaction system, providing heat, reducing the temperature difference between the catalyst beds during the reaction process, ensuring the consistency of the temperature, and ensuring the normal progress of the reaction.

[0013] The reactor shell and the reaction tube plate of the utility model are sealed by a sealing plate, so that the process system can only pass through the process medium cavity, thereby promoting the reaction; at the same time, in order to prevent the formation of negative pressure inside, ammonia is introduced into the shell between the two layers of sealing plates during the reaction process. The ammonia is mixed with the process medium through the through hole, which can also prevent the process medium mixture from entering between the sealing plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the present utility model. DETAILED DESCRIPTION

[0015] The embodiments of the present invention will be described in detail below with reference to the examples and drawings. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0016] like Figure 1 As shown, the utility model provides a caprolactam to aminocapronitrile reactor, comprising a reactor shell 1, a reaction tube plate 10 provided in the shell 1, the reaction tube plate being composed of process medium cavities 5 and heat medium cavities 4 arranged alternately, the heat medium cavity 4 being a closed cavity, one end of which is connected to a heating medium inlet pipe 2, and the other end of which is connected to a heating medium outlet pipe 8; the process medium cavity 5 is a structure with open top and bottom ends, and a bottom mesh provided at the bottom end, the process medium cavity 5 being filled with a catalyst. Through the design of the reaction tube plate, the heat medium in the heat medium cavity 4 can be used to heat the catalyst and process medium in the process medium cavity, ensuring that the reaction temperature reaches 300-350°C and the reaction proceeds smoothly. The bottom mesh can be made of a wire mesh or a plate with holes, and the hole size is preferably to prevent the catalyst from passing through.

[0017] In some embodiments, a sealing plate is provided between the edge of the reaction tube plate and the inner wall of the shell 1, which separates the reactor into independent spaces. The sealing plate design allows the process medium to pass only through the process medium cavity from one end of the shell to the other, ensuring that the process medium can fully react under catalytic conditions. The sealing plate can be installed and fixed by welding.

[0018] In a preferred embodiment, the sealing plate is provided with at least two layers, one layer being located between the top edge of the reaction tube plate and the inner wall of the shell, and the other layer being located between the bottom edge of the reaction tube plate and the inner wall of the shell, to avoid a pressure difference on both sides of the sealing plate.

[0019] In a more preferred embodiment, the sealing plate is provided with a through hole, and an air inlet pipe 9 is connected to the housing between the two sealing plates. During the reaction, a certain amount of ammonia gas is introduced into the air inlet pipe, and the ammonia gas mixes with the process medium through the through hole, thereby preventing the process medium gas from entering between the two sealing plates and ensuring pressure balance of the entire system.

[0020] In a further preferred embodiment, the diameter of the through hole is 5 mm-20 mm.

[0021] In some embodiments, the width between the process medium cavities 5 is 5 mm to 50 mm.

[0022] In some embodiments, there are multiple heat medium cavities 4, each of which is connected to the heating medium inlet pipe 2 via a heating medium inlet branch pipe 3; and each of which is connected to the heating medium outlet pipe 8 via a heating medium outlet branch pipe 11. Heat medium enters through the heating medium inlet pipe 2, is evenly dispersed into the heat medium cavity via the heating medium inlet branch pipe 3, and after heat exchange with the process medium cavity, is collected through the heating medium outlet branch pipe and discharged from the reactor.

[0023] After the gaseous mixture of caprolactam and ammonia enters the upper portion of the reactor, it passes through the tube sheet process medium cavity 5, which is internally loaded with a catalyst. The process medium reacts as it passes through, absorbing heat to generate the aminocapronitrile product, which exits the reactor in a gaseous state. The heating medium heats the tube sheet process medium cavity as it passes through the tube sheet thermal medium cavity 4. The thickness of the tube sheet process medium side is controlled to ensure a low loading and easy loading of the catalyst while ensuring a small temperature gradient and high consistency of the temperature distribution of the catalyst bed during the reaction process.

[0024] Ammonia gas is introduced through the air inlet pipe 9, and a through hole 7 is provided on the sealing plate 6 to ensure that the cavity formed by the sealing plate 6, the reactor shell 1, and the reaction tube plate 10 is basically balanced with the pressure of the process medium cavity in the reactor, ensuring that the reaction tube plate does not need to withstand a large pressure difference and preventing the process medium mixture from entering.

[0025] The above embodiments describe preferred implementations of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the present invention's technical solution may be made, including combining the various technical features in any other manner. These simple variations and combinations should also be considered as disclosures of the present invention and fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be based on the appended claims.

Claims

1. A caprolactam to aminocapronitrile reactor, characterized in that: The invention comprises a reactor shell (1), wherein a reaction tube plate is provided in the shell (1), and the reaction tube plate is formed by alternating arrangement of process medium cavities (5) and heat medium cavities (4), wherein the heat medium cavity (4) is a closed cavity, one end of the heat medium cavity (4) is connected to a heating medium inlet pipe (2), and the other end is connected to a heating medium outlet pipe (8); the process medium cavity (5) is a structure with an upper end and a lower end open, and a bottom net is provided at the lower end, and the process medium cavity (5) is filled with a catalyst.

2. The reactor according to claim 1, characterized in that: A sealing plate is provided between the edge of the reaction tube plate and the inner wall of the shell (1), and the sealing plate divides the reactor into independent spaces.

3. The reactor according to claim 2, characterized in that: The sealing plate is provided with at least two layers, one layer is located between the top edge of the reaction tube plate and the inner wall of the shell; the other layer is located between the bottom edge of the reaction tube plate and the inner wall of the shell.

4. The reactor according to claim 3, characterized in that: The sealing plate is provided with a through hole, and the shell between the two sealing plates is connected with an air inlet pipe.

5. The reactor according to claim 4, characterized in that: The diameter of the through hole is 5mm-20mm.

6. The reactor according to any one of claims 1 to 5, characterized in that: The width between the process medium cavities (5) is 5 mm to 50 mm.

7. The reactor according to any one of claims 1 to 5, characterized in that: There are multiple heat medium cavities (4), each heat medium cavity (4) is connected to the heating medium inlet pipe (2) via a heating medium inlet branch pipe (3); each heat medium cavity (4) is connected to the heating medium outlet pipe (8) via a heating medium outlet branch pipe (11).

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