Aminocapronitrile hydrogenation reaction device and method
By using a partition and a drop tube to separate the inactivated catalyst in the aminocapronitrile hydrogenation reaction device, and using the negative pressure suction cycle active catalyst of the venturi tube, the problem of difficulty in separation and wear after catalyst deactivation is solved, and the efficient separation and recycling of the catalyst is achieved, and the safety and efficiency of the reaction are improved.
Patent Information
- Application Number
- CN202411831654.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-04-11
AI Technical Summary
In the existing aminocapronitrile hydrogenation reaction process, it is difficult to efficiently separate the Rainey nickel catalyst after deactivation, resulting in catalyst wear and waste of resources.
An aminocapronitrile hydrogenation reaction device is designed. Through the arrangement of a partition and a drop tube, the inactivated catalyst is floated up and discharged through the overflow port for filtering and separation. The still active catalyst is recycled and reused through the negative pressure suction generated by the venturi tube.
Efficient separation and recycling of catalysts are achieved, catalyst wear and resource waste is avoided, and reaction safety and catalyst use efficiency are improved.
Smart Images
Figure CN119793334A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fine chemical industry and relates to an aminocapronitrile hydrogenation reaction device and method. Background Art
[0002] The hydrogenation of aminocapronitrile to produce hexamethylenediamine is a process route currently being developed in China for producing hexamethylenediamine and then nylon 66. The hydrogenation reaction of aminocapronitrile adopts a circulating fluidized bed reactor. The catalyst used is Raney nickel. At the same time, the hydrogenation reaction is an exothermic reaction, which ensures that the reaction cycle is reasonable and safe. The efficient recovery of the deactivated Raney nickel catalyst is a systemic problem. Summary of the invention
[0003] The invention provides an aminocapronitrile hydrogenation reaction device and method, which can effectively separate the deactivated catalyst, and the separated working fluid can be reused; for the catalyst that is still active, circulating hydrogen is used to generate negative pressure suction through a venturi tube to avoid wear of the catalyst during circulation.
[0004] The technical solution of the present invention is to provide an aminocapronitrile hydrogenation reaction device, comprising a reactor, which is divided into an upper reactor and a lower reactor by a partition, the partition connects the upper reactor and the lower reactor through a downcomer, the bottom of the downcomer is located at the middle and lower part of the lower reactor, an overflow port is provided at the upper part of the lower reactor, the overflow port is connected to a filtering device through a pipeline, a filtrate outlet of the filtering device is provided with a production pipe and a circulation branch pipe, the bottom of the lower reactor is connected to a discharge pipe, and the discharge pipe is connected to the feed port of the upper reactor through a circulation loop after merging with the circulation branch pipe.
[0005] Optionally, the reaction device further comprises a venturi tube, which is provided with an air inlet pipe, the discharge pipe of the lower reactor is connected to the throat of the venturi tube, and the outlet of the venturi tube merges with the circulation branch pipe.
[0006] Optionally, a gas phase outlet is provided at the top of the upper reactor, and the gas phase outlet is connected to the air inlet pipe of the venturi tube through a pipeline and a compressor; the air inlet pipe is also connected to a fresh hydrogen replenishment pipe.
[0007] Optionally, a cooling water jacket is provided on the pipeline of the circulation loop; a cooling water jacket is also provided on the pipeline between the overflow port of the lower reactor and the filtering device. The cooling water adopts circulating water, and the temperature in the pipeline is controlled at 60-90°C.
[0008] Optionally, there are multiple filtering devices, and the filtering devices are arranged in parallel.
[0009] Optionally, a circulation pump is provided on the circulation branch pipe, and a process medium feeding pipe is also connected to the circulation branch pipe.
[0010] Optionally, the height difference between the bottom of the downcomer and the discharge pipe opening at the bottom of the lower reactor is 400 mm to 700 mm.
[0011] The present invention also relates to a method for hydrogenating the aminocapronitrile, comprising the following steps: Aminocapronitrile and hydrogen are used as raw materials, and solvents and catalysts are added to react, wherein hydrogen is introduced from the air inlet pipe of the venturi tube, and other raw materials are introduced from the circulation branch pipe. The materials react in the reactor. When the materials enter the lower reactor, the deactivated catalyst floats up and is discharged from the overflow port with the feed liquid and the deactivated catalyst is intercepted by the filtering equipment, and the remaining filtrate is collected or recycled according to the situation; the material at the lower part of the lower reactor is combined with the gas phase of the air inlet pipe of the venturi tube at the throat of the venturi tube 8 through the discharge pipe, and then mixed with the material from the circulation branch pipe and sent to the upper reactor.
[0012] Optionally, the pressure of the reaction system is controlled at 2.0-3.0 MPa through a hydrogen supply pipe.
[0013] Optionally, the temperature of the material when entering the reactor is controlled to be 60-90°C. The present invention has the following beneficial effects: The inventors have found that during the aminocapronitrile hydrogenation reaction, the density of the Raney nickel catalyst becomes lighter after deactivation. The present invention can introduce the material in the upper reactor into the middle and lower part of the lower reactor through the arrangement of a partition and a downcomer. As the catalyst is deactivated, it moves upward until it overflows out of the reactor and is filtered and separated. The catalyst that is still active is discharged from the bottom of the lower reactor for circulation. The use of this device can effectively separate the deactivated catalyst and the catalyst that is still active, thereby avoiding waste.
[0014] After the deactivated catalyst is separated, the material is extracted and / or circulated according to the situation. By adding a venturi tube, the surplus hydrogen in the reactor is used to generate negative pressure, which is mixed with the catalyst working liquid that is still active from the bottom of the lower reactor at the throat, and then mixed with the material after the deactivated catalyst is separated by the filtering device and then participates in the circulation. This structure can also reduce the wear of the catalyst during circulation and increase the life of the catalyst.
[0015] The device provided by the present invention can efficiently extract the waste catalyst, improve the use efficiency of the catalyst, reduce the investment, and improve the safety of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION
[0017] The embodiments of the present invention will be described in detail below in conjunction with examples and drawings, but 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.
[0018] like Figure 1 As shown, the present invention provides an aminocapronitrile hydrogenation reaction device, including a reactor 1, which is divided into an upper reactor and a lower reactor by a partition 3, and the partition 3 connects the upper reactor and the lower reactor through a downcomer 4, the bottom of the downcomer is located at the middle and lower part of the lower reactor, and the upper part of the lower reactor is provided with an overflow port 2, and the overflow port 2 is connected to a filter device 6 through a pipeline, and the filtrate outlet of the filter device 6 is provided with a production pipe 11 and a circulation branch pipe 12, and the bottom of the lower reactor is connected with a discharge pipe, and the discharge pipe is connected to the feed port of the upper reactor through a circulation loop after merging with the circulation branch pipe. The device can be used to separate the deactivated catalyst in time, and avoid the production of the catalyst that is still active. The filtrate obtained by the filter device is produced according to the situation, or circulated for further reaction.
[0019] In some embodiments, the reaction device further comprises a venturi tube 8, which is provided with an air inlet pipe 9, the discharge pipe of the lower reactor is connected to the throat of the venturi tube 8, and the outlet of the venturi tube 8 merges with the circulation branch pipe. The material containing the catalyst in the lower reactor is drawn out and circulated by negative pressure, and the catalyst that is still active re-participates in the reaction.
[0020] In some embodiments, a gas phase outlet is provided at the top of the upper reactor, and the gas phase outlet is connected to the air inlet pipe 9 of the venturi tube 8 through a pipeline and a compressor 13; the air inlet pipe 9 is also connected to a fresh hydrogen replenishment pipe 14.
[0021] In some embodiments, there are multiple filtering devices, and the filtering devices are arranged in parallel to facilitate cleaning of filter residues without affecting the continuous operation of production.
[0022] In some embodiments, the circulation branch pipe is provided with a circulation pump 7, and the circulation branch pipe is also connected to a process medium feeding pipe 10. The reactor can also be arranged at a lower position, which greatly reduces the investment in the device, and at the same time, the potential safety hazards of the reaction caused by catalyst blockage are forcibly avoided. The active catalyst circulation does not need to pass through the circulation pump, which reduces the wear of the catalyst. The head of the circulation pump 7 is 5-20 meters.
[0023] In some embodiments, the height difference between the bottom of the downcomer and the discharge port at the bottom of the lower reactor is 400 mm to 700 mm. The material descending depth of the upper reactor is high, which can avoid carrying away the still active catalyst during the overflow process.
[0024] In some embodiments, a cooling water jacket 5 is provided on the circulation loop pipeline; a cooling water jacket 5 is also provided on the pipeline between the overflow port of the lower reactor and the filtering device, and the temperature in the pipeline is controlled at 60-90° C. The filtrate separated by the filtering device is mixed with fresh raw materials (containing aminocapronitrile and supplemented catalyst), and then mixed with the material mixed with the circulating hydrogen and the circulating catalyst through the venturi, and a hydrogenation reaction is carried out in the circulation pipeline. The reaction heat generated by the hydrogenation reaction is taken away by the cooling water in the cooling water jacket to ensure the reaction temperature balance.
[0025] Preferably, the reactor provided by the present invention is thin at the top and thick at the bottom, and the bottom of the lower reactor is conical, which is convenient for settling and extraction of active catalyst.
[0026] In some embodiments, the partition is a flat plate or funnel-shaped with a hole in the middle of the partition. The slurry after the reaction enters the lower reactor from the partition and the downcomer. The height between the bottom of the downcomer and the bottom discharge port of the lower reactor is 400 mm to 700 mm. The deactivated catalyst has a small density and will gradually rise and overflow from the lower reactor, and finally be filtered and separated.
[0027] The device provided by the present invention utilizes the lightening density of the Raney nickel catalyst after deactivation to efficiently extract the deactivated catalyst; and utilizes the circulating hydrogen to generate negative pressure through the venturi tube to suck the still active catalyst to re-participate in the reaction, thereby establishing a catalyst cycle and avoiding abrasion during the catalyst cycle. The reaction working liquid system adopts a circulating pump power cycle, which can lower the reactor layout position, greatly reduce the investment of the device, and avoid the safety hazards caused by catalyst blockage.
[0028] In the specific reaction operation, aminocapronitrile and hydrogen are used as raw materials, and solvents and catalysts are added for reaction, wherein hydrogen is introduced from the air inlet pipe of the venturi tube, and other raw materials are introduced from the circulation branch pipe. The materials react in the reactor. When the materials enter the lower reactor, the deactivated catalyst floats up and is discharged from the overflow port with the feed liquid and intercepted by the filtering equipment. The deactivated catalyst, the remaining filtrate is collected or circulated according to the situation; the material at the bottom of the lower reactor is combined with the gas phase of the air inlet pipe of the venturi tube at the throat of the venturi tube through the discharge pipe, and then mixed with the material from the circulation branch pipe and sent to the upper reactor. During the reaction, the pressure of the reaction system is controlled at 2.0-3.0MPa by the hydrogen replenishing pipe. The temperature in the pipeline is controlled at 60-90℃ by the cooling water jacket. The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. An aminocapronitrile hydrogenation reaction device, characterized in that: The invention comprises a reactor (1), which is divided into an upper reactor and a lower reactor by a partition (3), the partition (3) connects the upper reactor and the lower reactor through a downcomer (4), the bottom of the downcomer is located in the middle and lower part of the lower reactor, the upper part of the lower reactor is provided with an overflow port (2), the overflow port (2) is connected to a filter device (6) through a pipeline, the filtrate outlet of the filter device (6) is provided with a sampling pipe (11) and a circulation branch pipe, the bottom of the lower reactor is connected to a discharge pipe, and the discharge pipe is connected to the feed port of the upper reactor through a circulation loop after merging with the circulation branch pipe.
2. The device according to claim 1, characterized in that: The reaction device further comprises a venturi tube (8) which is provided with an air inlet pipe (9); the discharge pipe of the lower reactor is connected to the throat of the venturi tube (8); and the outlet of the venturi tube (8) merges with the circulation branch pipe.
3. The device according to claim 1, characterized in that: A gas phase outlet is provided at the top of the upper reactor, and the gas phase outlet is connected to an air inlet pipe (9) of the venturi tube (8) through a pipeline and a compressor (12); the air inlet pipe (9) is also connected to a fresh hydrogen replenishment pipe (13).
4. The device according to claim 1, characterized in that: A cooling water jacket is provided on the pipeline of the circulation loop; a cooling water jacket is also provided on the pipeline between the overflow port of the lower reactor and the filtering device.
5. The device according to claim 1, characterized in that: There are multiple filtering devices, and the filtering devices are arranged in parallel.
6. The device according to claim 1, characterized in that: The circulation branch pipe is provided with a circulation pump (7), and the circulation branch pipe is also connected to a process medium feed pipe (10).
7. The device according to any one of claims 1 to 6, characterized in that: The height difference between the bottom of the downcomer and the discharge pipe opening at the bottom of the lower reactor is 400 mm to 700 mm.
8. The method for hydrogenating aminocapronitrile according to any one of claims 1 to 7, characterized in that: The following steps are involved: Aminocapronitrile and hydrogen are used as raw materials, and a solvent and a catalyst are added to react, wherein hydrogen is introduced from an air inlet pipe (9) of a venturi tube (8), and other raw materials are introduced from a circulation branch pipe. The materials react in a reactor (1). When the materials enter the lower reactor, the deactivated catalyst floats up and is discharged from an overflow port with the feed liquid and the deactivated catalyst is intercepted by a filtering device. The remaining filtrate is collected or recycled according to the situation. The material at the lower part of the lower reactor is discharged through a discharge pipe and the air inlet pipe (9) of the venturi tube (8) and the gas phase is combined at the throat of the venturi tube (8), and then mixed with the material from the circulation branch pipe and sent to the upper reactor.
9. The method according to claim 8, characterized in that: The pressure of the reaction system is controlled at 2.0-3.0MPa through the hydrogen replenishment pipe.
10. The method according to claim 8, characterized in that: The temperature of the material when entering the reactor (1) is controlled to be 60-90°C.