A system for the production of 2-pyrrolidone

Abstract

The utility model provides a kind of 2-pyrrolidone production system, including control module, material mixing device connected in turn, heat exchange device with reaction pipeline and heat exchange medium pipeline and rectification purification device, the material mixing device includes first mixing bin, the storage bin of being arranged at the top of first mixing bin and the second mixing bin of being arranged at the bottom of first mixing bin, valve and flowmeter are arranged on the pipeline between the storage bin and first mixing bin, the control module is signal connected with valve and flowmeter. The utility model carries out detection and control to the valve and flowmeter of control module and storage bin discharge port, carries out accurate quantitative feeding and automatic control, reduces the generation of by-product, saves manpower cost.

Description

Technical Field

[0001] This utility model relates to the field of 2-pyrrolidone preparation technology, and specifically to a 2-pyrrolidone production system. Background Technology

[0002] The γ-butyrolactone (GBL) amination method is currently the most mature industrial route for the production of 2-pyrrolidone. The process involves using GBL and liquid ammonia as raw materials, followed by an addition reaction to produce 4-hydroxybutyramide and a cyclization reaction to produce 2-pyrrolidone. The core advantage of this route is that the supply of GBL has been reduced in cost due to the scaling up of the 1,4-butanediol (BDO) industrial chain. Modern large-scale plants generally employ continuous reactor designs, using a combined distillation-crystallization process to achieve a product purity of ≥99.5%, meeting the requirements for pharmaceutical applications.

[0003] However, the raw material feeding process has long faced two major technical bottlenecks: First, high reliance on manual labor: key raw materials (such as γ-butyrolactone and liquid ammonia) need to be added to the high-pressure reactor in batches manually or semi-automatically, with each feeding taking ≥30 minutes (based on a 5-ton reactor), resulting in an effective reaction time of less than 60%. Second, difficulty in quantitative control: amination reactions require strict control of the ammonia / ester molar ratio, but liquid ammonia often deviates from the actual feeding value by ±8% due to vaporization losses, leading to two types of problems: excessive ammonia: increased byproducts and decreased purity; insufficient ammonia: accumulation of unreacted γ-butyrolactone, accelerating the deactivation rate of the catalytic system. Therefore, the existing technology needs further development. Utility Model Content

[0004] This invention provides a production system for 2-pyrrolidone, the specific implementation of which is as follows: A 2-pyrrolidone production system includes a control module, a material mixing device, a heat exchange device with a reaction pipeline and a heat exchange medium pipeline connected in sequence, and a distillation and purification device. The material mixing device includes a first mixing chamber, a storage chamber located at the top of the first mixing chamber, and a second mixing chamber located at the bottom of the first mixing chamber. Valves and flow meters are installed on the pipeline between the storage chamber and the first mixing chamber. The control module is signal-connected to the valves and flow meters.

[0005] Furthermore, the storage silo includes a first storage silo for storing liquid ammonia, a second storage silo for storing ammonia water, and a third storage silo for storing γ-butyrolactone. The top of the first mixing silo is provided with a silo cover, and the silo cover is provided with a first inlet, a second inlet, and a third inlet respectively corresponding to the first storage silo, the second storage silo, and the third storage silo.

[0006] Furthermore, a first valve and a first flow meter are installed on the pipeline between the first storage silo and the first inlet, a second valve and a second flow meter are installed on the pipeline between the second storage silo and the second inlet, and a third valve and a third flow meter are installed on the pipeline between the third storage silo and the third inlet.

[0007] Furthermore, the distillation and purification device includes a deammoniation tower, a dehydration tower, a light gas removal tower, and a heavy gas removal tower connected in sequence. The ammonia outlet of the deammoniation tower is connected to an ammonia concentration tower, and the outlet of the ammonia concentration tower is connected to a storage silo via a pipeline.

[0008] Furthermore, the inlet of the second storage silo is connected to the outlet of the ammonia concentration tower via a pipeline.

[0009] Furthermore, the first mixing chamber and the second mixing chamber are respectively equipped with a first stirring structure and a second stirring structure.

[0010] Furthermore, the first stirring structure is a clockwise rotating stirring structure, and the second stirring structure is a counterclockwise rotating stirring structure.

[0011] Furthermore, the second mixing chamber is a funnel-shaped mixing chamber, with its wide end connected to the first mixing chamber.

[0012] Furthermore, the reaction pipe of the heat exchange device is equipped with spiral blades.

[0013] Beneficial effects: 1. The control module, the valve at the discharge port of the storage silo, and the flow meter of this utility model work together to precisely and automatically regulate the feeding of each raw material, maintaining the optimal feeding mass ratio of liquid ammonia: ammonia water: GBL = 1:1:5.4, reducing the generation of by-products and saving labor costs. Simultaneously, the control module automatically controls the valves to achieve continuous feeding of liquid ammonia, ammonia water, and GBL through three channels, eliminating the influence of feeding intervals on the reaction.

[0014] 2. This invention employs a funnel-shaped second mixing chamber. The funnel shape facilitates the discharge of mixed raw materials, ensuring thorough final mixing. Furthermore, the wide end of the funnel-shaped mixing chamber connects to the first mixing chamber, directly linking the two chambers and shortening the secondary transportation process. The synergistic effect of the primary and secondary mixing chambers significantly improves the uniformity of material mixing, while simultaneously increasing product mixing efficiency and saving time and labor costs.

[0015] 3. In the mixing structure, the first mixing structure rotates clockwise, and the second mixing structure rotates counterclockwise. The superposition effect of the velocity gradient generated by the counterclockwise rotation increases the turbulent kinetic energy by 2.3 times under the same fluid density, achieving low-power, high-efficiency mixing. Counterclockwise mixing reduces the fluid shear rate from 15s... -1 Increased to 40s -1 The micro-mixing time is reduced to 0.8 seconds (compared to 2.5 seconds in the traditional time). Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the production process of 2-pyrrolidone according to this utility model; Figure 2 This is a schematic diagram of the mixing chamber of this utility model.

[0017] Figure 3 This is a schematic diagram of the spiral blade of this utility model.

[0018] The above-mentioned attached figures include the following reference numerals: 1. Control module; 21. First storage bin; 211. First discharge port; 22. Second storage bin; 221. Second discharge port; 23. Third storage bin; 231. Third discharge port; 31. First valve; 32. Second valve; 33. Third valve; 41. First flow meter; 42. Second flow meter; 43. Third flow meter; 51. First mixing bin; 511. First inlet; 512. Second inlet 513. Feed inlet; 514. First stirring structure; 52. Second mixing chamber; 521. Second stirring structure; 61. Heat exchanger; 611. Heat exchange medium inlet; 612. Heat exchange medium outlet; 62. Reaction pipeline; 621. Reaction pipeline inlet; 622. Reaction pipeline outlet; 71. Ammonia removal tower; 711. Ammonia outlet end; 72. Dehydration tower; 73. Light weight removal tower; 74. Heavy weight removal tower; 75. Ammonia concentration tower; 8. Product storage tank. Detailed Implementation

[0019] The specific embodiments of this utility model are described below with reference to the accompanying drawings and examples: It should be noted that the structures, proportions, sizes, etc. shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0020] Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of implementation of this utility model.

[0021] According to an embodiment of this utility model, a production system for 2-pyrrolidone is provided. Please refer to [link / reference]. Figures 1-3 The system includes a control module 1, a material mixing device connected in sequence, a heat exchange device 61 with a reaction pipeline 62 and a heat exchange medium pipeline, and a distillation and purification device. The material mixing device includes a first mixing chamber 51, a storage chamber located at the top of the first mixing chamber 51, and a second mixing chamber 52 located at the bottom of the first mixing chamber 51. Valves and flow meters are installed on the pipeline between the storage chamber and the first mixing chamber 51. The control module 1 is signal-connected to the valves and flow meters. The control module 1 controls the feed rate of the raw materials by detecting the raw material flow rate at the outlet. The control module 1, the valve at the outlet of the storage chamber, and the flow meter work together to accurately and automatically regulate the feeding of each raw material, maintaining the optimal feed mass ratio of liquid ammonia: ammonia water: GBL = 1:1:5.4, reducing the generation of by-products and saving labor costs. At the same time, the control module 1 automatically controls the valves to achieve continuous feeding of liquid ammonia, ammonia water, and GBL through three channels, eliminating the influence of batch feeding intervals on the reaction.

[0022] The storage silos include a first storage silo 21 for storing liquid ammonia, a second storage silo 22 for storing ammonia water, and a third storage silo 23 for storing γ-butyrolactone (GLB). The top of the first mixing silo 51 is equipped with a cover, and the cover has a first inlet 511, a second inlet 512, and a third inlet 513 corresponding to the first storage silo 21, the second storage silo 22, and the third storage silo 23, respectively. The first storage silo 21, the second storage silo 22, and the third storage silo 23 are respectively equipped with a first outlet 211, a second outlet 221, and a third outlet 231. Liquid ammonia enters the first mixing silo 51 through the first outlet 211 and the first inlet 511; ammonia water enters the first mixing silo 51 through the second outlet 221 and the second inlet 512; and γ-butyrolactone enters the first mixing silo 51 through the third outlet 231 and the third inlet 513.

[0023] A first valve 31 and a first flow meter 41 are installed on the pipeline between the first storage silo 21 and the first inlet 511. A second valve 32 and a second flow meter 42 are installed on the pipeline between the second storage silo 22 and the second inlet 512. A third valve 33 and a third flow meter 43 are installed on the pipeline between the third storage silo 23 and the third inlet 513. The control module 1 is connected to the first valve 31 and the first flow meter 41, the second valve 32 and the second flow meter 42, and the third valve 33 and the third flow meter 43 via signals. By monitoring the change in the flow rate of the raw material at the outlet of the storage silo, the opening degree of the valves is adjusted. The designed ratio is liquid ammonia: ammonia water (10%): GBL of 1:1.2:5.5. In actual operation, the optimal yield is achieved under the condition of liquid ammonia: ammonia water (10%): GBL of 1:1:5.4. Therefore, control module 1 automatically adjusts the valves to precisely maintain the mass ratio of liquid ammonia, ammonia water, and GBL at 1:1:5.4 to ensure the optimal yield of 2-pyrrolidone. At the same time, the automatic valve adjustment by control module 1 realizes the continuous operation of the entire process. The automatic control unit controls the three-channel feeding of liquid ammonia, ammonia water (10%), and GBL, eliminating the batch intervals and feeding sequence intervals of manual feeding, and increasing the production capacity by 22%.

[0024] The distillation and purification apparatus includes a deammoniation tower 71, a dehydration tower 72, a light-weight gas removal tower 73, and a heavy-weight gas removal tower 74 connected in sequence. The ammonia outlet 711 of the deammoniation tower 71 is connected to an ammonia concentration tower 75, and the outlet of the ammonia concentration tower 75 is connected to a storage silo via a pipeline. The deammoniation tower 71 has two layers of packing, with the inlet located above the first layer. The inlet temperature is 150-160℃. After the crude product passes through the deammoniation tower 71 to remove water and ammonia, it enters the dehydration tower 72. The removed ammonia then enters the ammonia concentration tower 75. The reflux ratio of the deammoniation tower 71 is 2:1. The dehydration tower 72 also has two layers of packing, with the inlet located above the first layer. The inlet temperature is 170-180℃. After the crude product passes through the dehydration tower 72 to remove water, it enters the light-weight gas removal tower 73. Light component removal tower 73 has four layers of packing and two inlets, one of which is located above the second layer of packing. The feed temperature is 170-180℃. After the light components are removed in tower 73, the crude product enters heavy component removal tower 74. Heavy component removal tower 74 has six layers of packing, with the feed inlet located above the second layer of packing. The feed temperature is 175-182℃. After the heavy component is removed in heavy component removal tower 74, the crude product is processed to obtain a qualified product. The qualified product then enters product storage tank 8.

[0025] The inlet of the second storage silo 22 is connected to the outlet of the ammonia concentration tower 75 via a pipeline. The ammonia concentration tower 75 has two layers of packing, with the inlet located at the top of the tower. The feed temperature is 55-62℃. The ammonia concentration tower 75 concentrates the ammonia removed by the ammonia stripping tower 71 and recovers it to the second storage silo 22 for reuse. This reuse process, which mixes recovered ammonia with fresh ammonia, saves on the use of raw ammonia water and improves economic efficiency.

[0026] like Figure 2 The first mixing chamber 51 and the second mixing chamber 52 are respectively provided with a first stirring structure 514 and a second stirring structure 521. The first stirring structure 514 and the second stirring structure 521 thoroughly stir and mix the raw materials, and the speed of the first stirring structure 514 and the second stirring structure 521 can be adjusted according to different situations.

[0027] The first stirring structure 514 rotates clockwise, and the second stirring structure 521 rotates counterclockwise. The velocity gradient superposition effect generated by the counterclockwise rotation increases the turbulent kinetic energy by 2.3 times under the same fluid density, achieving low-power and high-efficiency mixing. Counterclockwise stirring reduces the fluid shear rate from 15s... -1 Increased to 40s -1， The micro-mixing time is reduced to 0.8 seconds (compared to 2.5 seconds in the traditional time).

[0028] The second mixing chamber 52 is a funnel-shaped mixing chamber, with its wide end connected to the first mixing chamber 51. The first mixing chamber 51 and the second mixing chamber 52 work together to significantly improve the uniformity of material mixing, and increase product mixing efficiency while saving time and labor costs.

[0029] like Figure 3 The heat exchanger 61 has a spiral vane 623 installed inside the reaction pipe 62. As the raw materials are transported within the heat exchanger 61, they pass through the spiral vane, further enhancing the mixing and heat exchange effect. The heat exchanger 61 includes a heat exchange medium inlet 611 and a heat exchange medium outlet 612 for the flow of the heat exchange medium. The reaction pipe 62 includes a reaction pipe inlet 621 and a reaction pipe outlet 622. The reaction pipe inlet 621 connects to a second mixing chamber 52. The mixture enters the reaction pipe 62 from the second mixing chamber 52 via the reaction pipe inlet 621 to generate the crude 2-pyrrolidone product. The production conditions within the heat exchanger 61 are a cyclization reaction at 255-260℃ and 7.1-7.2 MPa. The reaction pipe outlet 622 connects to a deammoniation tower 71. The crude reaction product enters the deammoniation tower 71 from the reaction pipe outlet 622 via a transport pipe.

[0030] The specific process is as follows: The raw materials, liquid ammonia, ammonia water (10%), and GBL, are controlled by the control module 1 to flow from the first discharge port 211, the second discharge port 221, and the third discharge port 233, respectively, and then through the first inlet port 511, the second inlet port 512, and the third inlet port 513 into the first mixing chamber 51. The control module 1 monitors the raw material flow rate and controls the valve size to ensure that the mass ratio of liquid ammonia, ammonia water (10%), and GBL is always 1:1:5.4. The raw materials, liquid ammonia, ammonia water (10%), and GBL are initially mixed in the first mixing chamber 51 by the first stirring structure 514, and then fall directly into the second mixing chamber 52 for further mixing by the second stirring structure 521. The resulting mixture enters the reaction pipeline through the reaction pipeline inlet 621, and after the reaction is completed in the reaction pipeline 62, a crude product is obtained. The reaction pipeline 62 is located inside the heat exchange device 61. The material undergoes a cyclization reaction at 255-260℃ and 7.1-7.2MPa within the heat exchange device 61. The heat exchange device 61 includes a heat exchange medium inlet 611 and a heat exchange medium outlet 612, and is capable of exchanging the heat exchange medium.

[0031] The crude product enters the ammonia removal tower 71 through the reaction pipeline outlet 622. After removing water and ammonia, the product enters the dehydration tower 72, and the removed ammonia enters the ammonia concentration tower 75. The recovered ammonia obtained from the ammonia concentration tower 75 enters the second storage silo 22 through the feed inlet for reuse. The crude product, after removing water in the dehydration tower 72, enters the light component removal tower 73. After removing light components in the light component removal tower 73, the crude product enters the heavy component removal tower 74. After removing heavy components in the heavy component removal tower 74, the crude product yields a qualified product. The qualified product enters the product storage tank 8.

Claims

1. A production system for 2-pyrrolidone, characterized in that, It includes a control module, a material mixing device connected in sequence, a heat exchange device having a reaction pipeline and a heat exchange medium pipeline, and a rectification and purification device. The material mixing device includes a first mixing bin, a storage bin arranged at the top of the first mixing bin, and a second mixing bin arranged at the bottom of the first mixing bin. A valve and a flowmeter are arranged on the pipeline between the storage bin and the first mixing bin, and the control module is in signal connection with the valve and the flowmeter; The storage bin includes a first storage bin for storing liquid ammonia, a second storage bin for storing ammonia water, and a third storage bin for storing γ-butyrolactone. A bin cover is arranged at the top of the first mixing bin, and a first feed inlet, a second feed inlet, and a third feed inlet are respectively arranged on the bin cover corresponding to the first storage bin, the second storage bin, and the third storage bin; A first valve and a first flowmeter are arranged on the pipeline between the first storage bin and the first feed inlet, a second valve and a second flowmeter are arranged on the pipeline between the second storage bin and the second feed inlet, and a third valve and a third flowmeter are arranged on the pipeline between the third storage bin and the third feed inlet; A first stirring structure and a second stirring structure are respectively arranged in the first mixing bin and the second mixing bin; The first stirring structure is a stirring structure that rotates clockwise, and the second stirring structure is a stirring structure that rotates counterclockwise; The second mixing bin is a funnel-shaped mixing bin, and the wide-mouth end of the funnel-shaped mixing bin is connected to the first mixing bin.

2. The production system of 2-pyrrolidone according to claim 1, wherein The rectification and purification device includes a deammoniation tower, a dehydration tower, a light component removal tower, and a heavy component removal tower connected in sequence. The ammonia gas outlet end of the deammoniation tower is connected to an ammonia concentration tower, and the outlet of the ammonia concentration tower is connected to the storage bin through a pipeline.

3. The production system of 2-pyrrolidone according to claim 2, wherein The feed inlet of the second storage bin is connected to the outlet of the ammonia concentration tower through a pipeline.

4. The production system of 2-pyrrolidone according to claim 1, wherein Spiral fins are arranged in the reaction pipeline of the heat exchange device.

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