A synthesis device for N-vinyl pyrrolidone

Abstract

The utility model relates to the field of chemical technology, and specifically to a synthesis device for N-vinyl pyrrolidone, including a catalyst preparation tower, an acetylene absorption tower, an ethylene reactor, a heavy removal tower, a light removal tower, and a matching heat exchange and circulation device. The utility model realizes efficient coordination of raw material dehydration, acetylene absorption and ethylene reaction through the continuous series structure design of the catalyst preparation tower, the acetylene absorption tower and the ethylene reactor, and the acetylene absorption efficiency is improved. At the same time, combined with a multi-stage heat integrated heat exchange system, the comprehensive energy consumption is reduced, and the final NVP product purity is stable and reaches the pharmaceutical grade standard.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical industry, in particular to a synthesis device of N-vinyl pyrrolidone. Background Art

[0002] N-vinylpyrrolidone (NVP) is an important monomer in the fields of medicine, cosmetics and polymer materials. Its industrial production is mainly achieved through the vinylation reaction of 2-pyrrolidone (2-PY) and acetylene. The traditional process generally adopts an intermittent operation mode, which has the following technical bottlenecks:

[0003] Low catalyst dehydration efficiency: After 2-PY is mixed with KOH aqueous solution, water must be removed to the maximum extent possible to ensure the activity of the catalyst. However, traditional dehydration equipment usually uses vacuum evaporation, which has low evaporation efficiency, long evaporation time and poor dehydration effect, resulting in incomplete dehydration (residual water> 0.5wt%), which directly affects the efficiency of subsequent ethylene reaction.

[0004] Insufficient acetylene utilization: The existing technology usually requires acetylene and inert gas to be mixed and then sent into the reactor to react under the action of the catalyst. Due to the difficulty of gas-liquid two-phase mass transfer, the mass transfer efficiency is very low and the distribution in the reactor is uneven. Therefore, excess acetylene is required to ensure the acetylene concentration. A large amount of unreacted acetylene and inert gas need to be recycled, resulting in large equipment investment and high energy consumption.

[0005] The existing technology (such as CN119059956A) attempts to alleviate the above problems by modifying the preparation process, but does not fundamentally solve the core defects of poor equipment coordination and low acetylene utilization. Therefore, it is urgent to develop an integrated and continuous NVP production system to improve process efficiency through structural innovation. Utility Model Content

[0006] The purpose of the utility model is to provide a synthesis device for N-vinyl pyrrolidone in order to overcome the defects of the above-mentioned prior art. Through the continuous series structure design of the catalyst preparation tower, the acetylene absorption tower and the ethylene reactor, the efficient coordination of the raw material catalyst dehydration, acetylene absorption and ethylene reaction is achieved, thereby improving the reaction efficiency.

[0007] The purpose of the utility model can be achieved through the following technical solutions:

[0008] The utility model provides a synthesis device of N-vinyl pyrrolidone, comprising a catalyst preparation tower, an acetylene absorption tower, an ethylene reactor, a heavy removal tower, a light removal tower, an NVP product refining tower, and a 2-PY recovery tower, wherein specifically:

[0009] A catalyst preparation tower, which is an azeotropic distillation tower, used to remove water from 2-PY and KOH aqueous solution through azeotropic distillation to prepare a bottom liquid containing 2-pyrrolidone potassium salt;

[0010] An acetylene absorption tower is used to cool the bottom liquid containing potassium salt of 2-pyrrolidone and then contact it with pressurized acetylene in countercurrent to obtain a liquid phase in which acetylene is dissolved;

[0011] An ethylene reactor connected to the acetylene absorption tower is used to cause a liquid phase containing dissolved acetylene to undergo an ethylene reaction with 2-PY to generate NVP;

[0012] A deweighting tower connected to the ethylene reactor and used to separate heavy impurities in the reaction liquid of the ethylene reactor;

[0013] A light-removal tower connected to the heavy-removal tower is used to remove light component impurities in the removal reaction liquid output from the heavy-removal tower;

[0014] NVP product refining tower, connected to the light removal tower, used to further purify the reaction liquid output from the light removal tower to obtain NVP product;

[0015] The 2-PY recovery tower is connected to the NVP product refining tower and the catalyst preparation tower respectively, and is used to recover unreacted 2-PY and circulate it to the catalyst preparation tower for repeated use.

[0016] Furthermore, it also includes a feed preheater, wherein the first heat exchange channel input end of the feed preheater is connected to the bottom of the catalyst preparation tower, and the first heat exchange channel output end of the feed preheater is connected to the top of the acetylene absorption tower.

[0017] Furthermore, it also includes a static mixer, the input end of the static mixer is used to respectively introduce 2-PY and KOH aqueous solution, the output end of the static mixer is connected to the input end of the second heat exchange channel of the feed preheater, and the output end of the second heat exchange channel of the feed preheater is connected to the middle part of the catalyst preparation tower to realize the feeding of 2-PY and KOH aqueous solution.

[0018] Furthermore, it also includes an acetylene feed compressor and a tail gas condenser, wherein the input end of the acetylene feed compressor is used for the introduction of fresh acetylene, and the input end of the acetylene feed compressor is connected to the tail gas condenser, the tail gas condenser is connected to the top of the acetylene absorption tower, the tail gas condenser is used to condense the acetylene that is not absorbed at the top of the tower and send it to the acetylene feed compressor, and the output end of the acetylene feed compressor is connected to the bottom of the acetylene absorption tower.

[0019] Furthermore, it also includes a crude NVP heat exchanger and a crude NVP storage tank, the inlet of the first heat exchange channel of the crude NVP heat exchanger is connected to the bottom discharge port of the ethylene reactor, the outlet of the first heat exchange channel of the crude NVP heat exchanger is connected to the crude NVP storage tank, the inlet of the second heat exchange channel of the crude NVP heat exchanger is connected to the bottom discharge port of the acetylene absorption tower, and the outlet of the second heat exchange channel of the crude NVP heat exchanger is connected to the feed port at the top of the ethylene reactor.

[0020] Furthermore, the outlet of the first heat exchange channel of the crude NVP heat exchanger is also connected to the top of the acetylene absorption tower, so that part of the reaction liquid of the ethylene reactor is returned to the acetylene absorption tower, thereby forming a cycle.

[0021] Furthermore, the middle part of the deweighting tower is connected to the crude NVP storage tank to achieve middle feeding;

[0022] The top of the deweighting tower is matched with a deweighting tower full condenser, and the bottom of the deweighting tower is matched with a deweighting tower reboiler. The crude NVP output from the crude NVP storage tank is connected to the middle of the deweighting tower after heat exchange in the deweighting tower full condenser.

[0023] The output end of the de-weighting tower full condenser is also connected to a de-weighting tower distillation tank, and the bottom of the de-weighting tower distillation tank is connected to the middle of the de-lighting tower to achieve middle feeding.

[0024] Furthermore, the top of the light-removal tower is matched with a light-removal tower condenser, the bottom of the light-removal tower is matched with a light-removal tower reboiler, and the bottom discharge port of the light-removal tower is connected to the middle of the NVP product refining tower to realize middle feeding.

[0025] Furthermore, the top of the NVP product refining tower is matched with an NVP product refining tower condenser, and the bottom of the NVP product refining tower is matched with an NVP product refining tower reboiler;

[0026] The NVP product refining tower condenser is also connected to an NVP product refining tower full condenser, the input end of the NVP product refining tower full condenser is connected to the NVP product refining tower condenser, and the output end of the NVP product refining tower full condenser is connected to the middle part of the lightness removal tower;

[0027] The bottom of the NVP product refining tower is connected to the middle of the 2-PY recovery tower.

[0028] Furthermore, a 2-PY recovery tower condenser is matched at the top of the 2-PY recovery tower, and a 2-PY recovery tower condenser is matched at the bottom of the 2-PY recovery tower.

[0029] The 2-PY recovery tower condenser is connected to the static mixer, so that the recovered 2-PY and fresh 2-PY are mixed at the static mixer.

[0030] Compared with the prior art, the utility model has the following beneficial effects:

[0031] The utility model realizes efficient coordination of raw material dehydration, acetylene absorption and ethylene reaction through the continuous series structure design of the catalyst preparation tower, the acetylene absorption tower and the ethylene reactor, and the acetylene absorption efficiency is improved. At the same time, combined with the multi-stage heat integration heat exchange system, the comprehensive energy consumption is reduced, and finally the purity of the NVP product is stably achieved to meet the pharmaceutical grade standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the dehydration tower, acetylene absorption tower and ethylene reactor in the utility model;

[0033] Figure 2 It is a schematic diagram of the structure of the heavy removal tower, light removal tower, NVP product refining tower and 2-PY recovery tower in the utility model.

[0034] Explanation of the reference numerals: 1-catalyst preparation tower; 2-acetylene absorption tower; 3-ethylene reactor; 5-heavy-removal tower; 6-light-removal tower; 7-NVP product refining tower; 8-2-PY recovery tower; 9-crude NVP storage tank; 10-heavy-removal tower distillation tank; 11-static mixer; 12-feed preheater; 13-dehydration tower condenser; 14-catalyst preparation tower full condenser; 15-catalyst preparation tower reboiler; 16-catalyst cooler; 17-wastewater tank; 18-wastewater cooler; 19-tail gas condenser; 20-acetylene heat exchanger; 21-crude NVP heat exchanger; 22-crude NVP preheater; 23-ethylene reactor feed cooler; 24-heavy-removal tower condenser; 25-heavy-removal tower full condenser; 26-heavy-removal tower reboiler; 27-light-removal tower condenser; 28-light-removal tower Reboiler; 29-NVP product refining tower condenser; 30-NVP product cooler; 31-NVP product refining tower full condenser; 32-NVP product refining tower reboiler; 33-2-PY recovery tower condenser; 34-2-PY cooler; 35-2-PY recovery tower reboiler; 36-catalyst preparation tower kettle pump; 37-catalyst dehydration reflux pump; 38-catalyst preparation tower vacuum pump; 39-acetylene feed compressor; 40-reactor feed pump; 41-crude NVP feed pump; 42-heavy and light tower vacuum pump; 43 heavy and light tower kettle pump; 44-light tower kettle pump; 45-light component return pump; 46-NVP product refining tower kettle pump; 47-NVP and 2-PY tower vacuum pumps; 48-2-PY production pump; 49-2-PY tower kettle pump. DETAILED DESCRIPTION

[0035] The following is a detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0036] Example 1

[0037] The synthesis device of N-vinyl pyrrolidone in this embodiment includes a catalyst preparation tower 1, an acetylene absorption tower 2, an ethylene reactor 3, a heavy removal tower 5, a light removal tower 6, an NVP product refining tower 7, and a 2-PY recovery tower 8, wherein the specific Figure 1 and Figure 2 .

[0038] The catalyst preparation tower 1 is an azeotropic distillation tower, which is used to remove water from 2-PY and KOH aqueous solution through azeotropic distillation to prepare a bottom liquid containing 2-pyrrolidone potassium salt.

[0039] The synthesis device of N-vinyl pyrrolidone also includes a feed preheater 12, the first heat exchange channel input end of the feed preheater 12 is connected to the bottom of the catalyst preparation tower 1, and the first heat exchange channel output end of the feed preheater 12 is connected to the top of the acetylene absorption tower 2.

[0040] See also Figure 1 The output end of the feed preheater 12 is also connected to a catalyst cooler 16 , and the catalyst cooler 16 is connected to the top of the acetylene absorption tower 2 .

[0041] The synthesis device of N-vinyl pyrrolidone also includes a static mixer 11, the input end of the static mixer 11 is used to respectively introduce 2-PY and KOH aqueous solution, the output end of the static mixer 11 is connected to the input end of the second heat exchange channel of the feed preheater 12, and the output end of the second heat exchange channel of the feed preheater 12 is connected to the middle part of the catalyst preparation tower 1, so as to realize the feeding of 2-PY and KOH aqueous solution.

[0042] See also Figure 1 The top of the catalyst preparation tower 1 is matched with a dehydration tower condenser 13, and the bottom is matched with a catalyst preparation tower reboiler 15. The dehydration tower condenser 13 is also connected to a catalyst preparation tower full condenser 14, and the catalyst preparation tower full condenser 14 is connected to the middle part of the catalyst preparation tower 1.

[0043] During specific implementation, the top of the catalyst preparation tower full condenser 14 is also connected in sequence to a catalyst preparation tower vacuum pump 38, a wastewater cooler 18, and a wastewater tank 17.

[0044] The acetylene absorption tower 2 is used to cool the bottom liquid containing 2-pyrrolidone potassium salt and then contact it with pressurized acetylene in countercurrent to obtain a liquid mixture containing dissolved acetylene.

[0045] In specific implementation, the output end of the acetylene feed compressor 39 is also connected to the acetylene heat exchanger 20. The bottom of the acetylene absorption tower 2 is connected to the top of the ethylene reactor 3 through the ethylene reactor feed cooler 23.

[0046] It also includes a crude NVP heat exchanger 21 and a crude NVP storage tank 9, the inlet of the first heat exchange channel of the crude NVP heat exchanger 21 is connected to the bottom discharge port of the ethylene reactor 3, the outlet of the first heat exchange channel of the crude NVP heat exchanger 21 is connected to the crude NVP storage tank 9, the inlet of the second heat exchange channel of the crude NVP heat exchanger 21 is connected to the bottom discharge port of the acetylene absorption tower 2, and the outlet of the second heat exchange channel of the crude NVP heat exchanger 21 is connected to the feed port at the top of the ethylene reactor 3.

[0047] The ethylene reactor 3 is connected to the acetylene absorption tower 2 and is used to cause the liquid phase containing dissolved acetylene to undergo ethylene reaction with 2-PY to generate NVP.

[0048] It also includes an acetylene feed compressor 39 and a tail gas condenser 19, wherein the input end of the acetylene feed compressor 39 is used for the introduction of fresh acetylene, and the input end of the acetylene feed compressor 39 is connected to the tail gas condenser 19, and the tail gas condenser 19 is connected to the top of the acetylene absorption tower 2, and the tail gas condenser 19 is used to condense the acetylene that is not absorbed at the top of the tower and send it to the acetylene feed compressor 39, and the output end of the acetylene feed compressor 39 is connected to the bottom of the acetylene absorption tower 2.

[0049] The outlet of the first heat exchange channel of the crude NVP heat exchanger 21 is also connected to the top of the acetylene absorber 2, so that part of the reaction liquid of the ethylene reactor 3 is returned to the acetylene absorber 2, thereby forming a cycle. The deweighting tower 5 is connected to the ethylene reactor 3 to separate the heavy impurities in the reaction liquid of the ethylene reactor 3.

[0050] In specific implementation, it also includes a crude NVP preheater 22. After the bottom discharge of the ethylene reactor 3 passes through the crude NVP heat exchanger 21, a part enters the crude NVP storage tank 9, and a part passes through the crude NVP preheater 22 and is then sent back to the top of the acetylene absorption tower 2.

[0051] See also Figure 2, the middle part of the de-weighting tower 5 is connected to the crude NVP storage tank 9 to realize the middle feeding. The top of the de-weighting tower 5 is matched with a de-weighting tower full condenser 25, and the bottom of the de-weighting tower 5 is matched with a de-weighting tower reboiler 26. The crude NVP output from the crude NVP storage tank 9 is connected to the middle part of the de-weighting tower 5 after heat exchange with the de-weighting tower full condenser 25. The output end of the de-weighting tower full condenser 25 is also connected to the de-weighting tower distillation tank 10, and the bottom of the de-weighting tower distillation tank 10 is connected to the middle part of the lightness removal tower 6 to realize the middle feeding.

[0052] The top of the deweighting tower full condenser 25 is connected to the deweighting tower condenser 24 , and the deweighting tower condenser 24 is also connected to the deweighting tower distillation tank 10 .

[0053] The light-removing tower 6 is connected to the heavy-removing tower 5, and the heavy-removing tower 5 is used to remove light component impurities in the removal reaction liquid output by the heavy-removing tower 5; the top of the light-removing tower 6 is matched with a light-removing tower condenser 27, and the bottom of the light-removing tower 6 is matched with a light-removing tower reboiler 28, and the bottom discharge port of the light-removing tower 6 is connected to the middle of the NVP product refining tower 7 to realize middle feeding.

[0054] The light-removal tower condenser 27 and the heavy-removal tower condenser 24 are both matched and connected to the same heavy-removal tower vacuum pump 42 .

[0055] The NVP product refining tower 7 is connected to the light removal tower 6 to further purify the reaction liquid output from the light removal tower 6 to obtain the NVP product. The top of the NVP product refining tower 7 is matched with an NVP product refining tower condenser 29, and the bottom of the NVP product refining tower 7 is matched with an NVP product refining tower reboiler 32.

[0056] The NVP product refining tower condenser 29 is also connected to the NVP product refining tower full condenser 31, the input end of the NVP product refining tower full condenser 31 is connected to the NVP product refining tower condenser 29, and the output end of the NVP product refining tower full condenser 31 is connected to the middle part of the light removal tower 6;

[0057] The bottom of the NVP product refining tower 7 is connected to the middle of the 2-PY recovery tower 8. The 2-PY recovery tower 8 is connected to the NVP product refining tower 7 and the catalyst preparation tower 1, respectively, to recover unreacted 2-PY and circulate it to the catalyst preparation tower 1 for repeated use.

[0058] In specific implementation, the top of the 2-PY recovery tower 8 is matched with a 2-PY recovery tower condenser 33, and the bottom of the 2-PY recovery tower 8 is matched with a 2-PY recovery tower condenser 33. The 2-PY recovery tower condenser 33 is connected to a 2-PY cooler 34. The recovered 2-PY needs to pass through the cooler 34 before entering the static mixer 11. In this way, the recovered 2-PY is mixed with the fresh 2-PY at the static mixer 11.

[0059] The 2-PY recovery tower condenser 33 and the NVP product refining tower full condenser 31 are connected to both an NVP and 2-PY tower vacuum pump.

[0060] See also Figure 1 and Figure 2 In this embodiment, a plurality of pump devices are arranged at some places where power transmission is required, such as catalyst preparation tower kettle pump 36, catalyst dehydration reflux pump 37, reactor feed pump 40, crude NVP feed pump 41, heavy removal tower kettle pump 43, light removal tower kettle pump 44, light component return pump 45, NVP product refining tower kettle pump 46, NVP and 2-PY tower vacuum pump 47, 2-PY extraction pump 48, 2-PY tower kettle pump 49. The arrangement and selection of specific pumps can be adjusted as needed by those skilled in the art during specific implementation.

[0061] The utility model realizes efficient coordination of raw material dehydration, acetylene absorption and ethylene reaction through the continuous series structure design of catalyst preparation tower, acetylene absorption tower and ethylene reactor, and improves the acetylene absorption efficiency. At the same time, combined with multi-stage heat integration heat exchange system such as feed preheater and crude NVP heat exchanger, the comprehensive energy consumption is reduced, and the final NVP product purity is stable and reaches the pharmaceutical grade standard. The specific operation process is as follows:

[0062] Catalyst preparation tower 1 has a plate tower structure. The number of plates is designed to meet the requirements for rapid separation of the azeotropic system of 2-PY and water.

[0063] Raw material mixing: 2-PY (2-pyrrolidone) and KOH aqueous solution are fully mixed through a static mixer 11 to form a homogeneous solution.

[0064] Preheating and feeding: After being preheated by the second heat exchange channel of the feed preheater 12, the mixed liquid enters the middle part of the catalyst preparation tower 1.

[0065] A third component is added to the top of the tower, which is azeotropic with water and forms a two-liquid phase system. The water generated by the reaction is removed by azeotropic distillation, and a qualified K-PY (2-pyrrolidone potassium salt) reaction liquid is obtained in the bottom of the tower, which is used as a catalyst. The third component is propyl acetate or isopropyl acetate.

[0066] Azeotropic distillation dehydration:

[0067] The tower is heated by the catalyst preparation tower reboiler 15, and the azeotrope of 2-PY and water evaporates at the top of the tower, and is condensed by the dehydration tower condenser 13 and then separated into layers. The aqueous phase is discharged from the system, and the organic phase is partially refluxed into the tower.

[0068] The bottom liquid is a dehydrated 2-pyrrolidone potassium salt solution, which is transported to the acetylene absorption tower 2 via the catalyst preparation tower bottom pump 36. The number of theoretical plates of the distillation tower is 10-80.

[0069] The acetylene absorption tower 2 adopts a packed tower structure with built-in stainless steel wire mesh structured packing to enhance the gas-liquid mass transfer efficiency.

[0070] Acetylene absorption: The catalyst bottom liquid after spray cooling at the top of the tower is cooled by the catalyst cooler 16 and countercurrently contacts with the pressurized acetylene introduced from the bottom from the acetylene feed compressor 39. Acetylene is dissolved in the liquid phase, and the unabsorbed acetylene gas is discharged from the top of the tower, condensed and recovered by the tail gas condenser 19, and then returned to the compressor for recycling.

[0071] Liquid phase output: Rich liquid containing dissolved acetylene flows out from the bottom of the tower and enters the ethylene reactor 3 after being preheated by the crude NVP heat exchanger 21.

[0072] The ethylene reactor 3 adopts a kettle reactor, which can be filled with loose fillers (such as Raschig rings, ball rings, etc.), structured fillers or other types of fillers.

[0073] Vinylation reaction: The liquid phase of dissolved acetylene reacts with supplementary 2-PY in the reactor to produce NVP. The reaction temperature is controlled by the ethylene reactor feed cooler 23 to maintain the optimal reaction conditions such as 80-120°C.

[0074] Product treatment: The reaction liquid is discharged from the bottom, and after heat exchange and cooling with the discharge of the acetylene absorber in the crude NVP heat exchanger 21, part of it enters the crude NVP storage tank 9, and part of it is circulated to the top of the acetylene absorber 2 to adjust the absorption efficiency.

[0075] The deweighting tower 5 adopts a floating valve tower structure.

[0076] Separation of heavy components: Crude NVP enters the de-weighting tower from the middle, is heated by the de-weighting tower reboiler 26, and the light component NVP and unreacted 2-PY are evaporated from the top of the tower, condensed by the de-weighting tower full condenser 25, and enter the de-weighting tower distillation tank 10. Heavy component impurities such as polymers are discharged from the bottom of the tower and sent to waste treatment through the tower bottom pump 43.

[0077] Distillate treatment: The distillate is further cooled by the de-heavy tower condenser 24 and then enters the middle part of the light tower 6.

[0078] The lightness removal tower 6 adopts a floating valve tower structure.

[0079] Removal of light components: The feed is in gas-liquid contact in the middle, and light components such as residual acetylene and water are evaporated from the top of the tower, condensed in the light removal tower condenser 27, and discharged from the system. The bottom liquid is the NVP crude product with light components removed, which is heated in the light removal tower reboiler 28 and then transported to the NVP product refining tower 7.

[0080] NVP product refining tower 7 adopts high-efficiency wire mesh packing tower.

[0081] High-purity purification: The feed enters from the middle, is separated by distillation, and high-purity NVP is evaporated from the top of the tower, and is condensed by the NVP product refining tower condenser 29 and the NVP product refining tower full condenser 31 before being extracted as a product.

[0082] The 2-PY remaining in the bottom of the tower and a small amount of heavy components are transported to the 2-PY recovery tower 8.

[0083] 2-PY recovery tower 8 uses an inclined hole plate tower, which is suitable for separating high viscosity materials.

[0084] 2-PY recovery cycle: The feed is separated in the middle, and the 2-PY evaporated from the top of the tower is condensed by the condenser 33 and then returned to the static mixer 11 through the extraction pump 48 to be mixed with the new raw material for recycling.

[0085] The heavy components such as by-products remaining at the bottom of the tower are discharged from the system via the bottom pump 49.

[0086] Auxiliary equipment coordinated operation

[0087] Thermal integration design: The feed preheater 12 uses the heat of the catalyst preparation tower bottom liquid to preheat the raw materials, reducing energy consumption. The crude NVP heat exchanger 21 realizes heat exchange between the reaction liquid and the acetylene absorption liquid, optimizing heat utilization.

[0088] Vacuum system:

[0089] The de-heavy tower 5 and the de-light tower 6 share the de-heavy tower vacuum pump 42, and the NVP product refining tower 7 and the 2-PY recovery tower 8 share the vacuum pump 47, thereby reducing equipment investment.

[0090] The above description of the embodiments is to facilitate the understanding and use of the utility model by those skilled in the art. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the utility model is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the utility model without departing from the scope of the utility model should be within the scope of protection of the utility model.

Claims

1. A synthesis device for N-vinyl pyrrolidone, characterized in that: include: A catalyst preparation tower (1), wherein the catalyst preparation tower (1) is an azeotropic distillation tower, used to remove water from 2-PY and KOH aqueous solution through azeotropic distillation to prepare a bottom liquid containing 2-pyrrolidone potassium salt; An acetylene absorption tower (2) is used to cool the bottom liquid containing 2-pyrrolidone potassium salt and then contact it with pressurized acetylene in countercurrent to obtain a liquid phase in which acetylene is dissolved; An ethylene reactor (3) connected to the acetylene absorption tower (2) is used to cause a liquid phase containing dissolved acetylene to undergo an ethylene reaction with 2-PY to generate NVP; A deweighting tower (5), connected to the ethylene reactor (3), for separating heavy impurities from the reaction liquid of the ethylene reactor (3); A light-removal tower (6), connected to the heavy-removal tower (5), for removing light component impurities from the removal reaction liquid output from the heavy-removal tower (5); An NVP product refining tower (7) is connected to the light removal tower (6) and is used to further purify the reaction liquid output from the light removal tower (6) to obtain an NVP product; The 2-PY recovery tower (8) is connected to the NVP product refining tower (7) and the catalyst preparation tower (1) respectively, and is used to recover unreacted 2-PY and circulate it to the catalyst preparation tower (1) for repeated use.

2. The synthesis device of N-vinyl pyrrolidone according to claim 1, characterized in that: It also comprises a feed preheater (12), wherein the first heat exchange channel input end of the feed preheater (12) is connected to the bottom of the catalyst preparation tower (1), and the first heat exchange channel output end of the feed preheater (12) is connected to the top of the acetylene absorption tower (2).

3. The synthesis device of N-vinyl pyrrolidone according to claim 2, characterized in that: It also comprises a static mixer (11), the input end of the static mixer (11) is used to respectively introduce 2-PY and KOH aqueous solution, the output end of the static mixer (11) is connected to the input end of the second heat exchange channel of the feed preheater (12), and the output end of the second heat exchange channel of the feed preheater (12) is connected to the middle part of the catalyst preparation tower (1), so as to realize the feeding of 2-PY and KOH aqueous solution.

4. The synthesis device of N-vinyl pyrrolidone according to claim 1, characterized in that: The invention also comprises an acetylene feed compressor (39) and a tail gas condenser (19), wherein the input end of the acetylene feed compressor (39) is used for introducing fresh acetylene, and the input end of the acetylene feed compressor (39) is connected to the tail gas condenser (19), and the tail gas condenser (19) is connected to the top of the acetylene absorption tower (2). The tail gas condenser (19) is used for condensing the acetylene that is not absorbed at the top of the tower and sending it to the acetylene feed compressor (39), and the output end of the acetylene feed compressor (39) is connected to the bottom of the acetylene absorption tower (2).

5. The synthesis device of N-vinyl pyrrolidone according to claim 1, characterized in that: It also includes a crude NVP heat exchanger (21) and a crude NVP storage tank (9), wherein the inlet of the first heat exchange channel of the crude NVP heat exchanger (21) is connected to the bottom discharge port of the ethylene reactor (3), the outlet of the first heat exchange channel of the crude NVP heat exchanger (21) is connected to the crude NVP storage tank (9), the inlet of the second heat exchange channel of the crude NVP heat exchanger (21) is connected to the bottom discharge port of the acetylene absorption tower (2), and the outlet of the second heat exchange channel of the crude NVP heat exchanger (21) is connected to the feed port at the top of the ethylene reactor (3).

6. The synthesis device of N-vinyl pyrrolidone according to claim 5, characterized in that: The outlet of the first heat exchange channel of the crude NVP heat exchanger (21) is also connected to the top of the acetylene absorption tower (2), so that part of the reaction liquid of the ethylene reactor (3) returns to the acetylene absorption tower (2), thereby forming a cycle.

7. The synthesis device of N-vinyl pyrrolidone according to claim 5, characterized in that: The middle part of the deweighting tower (5) is connected to the crude NVP storage tank (9) to achieve middle feeding; The top of the deweighting tower (5) is matched with a deweighting tower full condenser (25), and the bottom of the deweighting tower (5) is matched with a deweighting tower reboiler (26). The crude NVP output from the crude NVP storage tank (9) is connected to the middle of the deweighting tower (5) after heat exchange in the deweighting tower full condenser (25); The output end of the de-weighting tower full condenser (25) is also connected to a de-weighting tower distillation tank (10), and the bottom of the de-weighting tower distillation tank (10) is connected to the middle of the de-lighting tower (6) to achieve middle feeding.

8. The synthesis device of N-vinyl pyrrolidone according to claim 1, characterized in that: The top of the light removal tower (6) is matched with a light removal tower condenser (27), the bottom of the light removal tower (6) is matched with a light removal tower reboiler (28), and the bottom discharge port of the light removal tower (6) is connected to the middle of the NVP product refining tower (7) to achieve middle feeding.

9. The synthesis device of N-vinyl pyrrolidone according to claim 1, characterized in that: The top of the NVP product refining tower (7) is matched with an NVP product refining tower condenser (29), and the bottom of the NVP product refining tower (7) is matched with an NVP product refining tower reboiler (32); The NVP product refining tower condenser (29) is also connected to an NVP product refining tower full condenser (31), the input end of the NVP product refining tower full condenser (31) is connected to the NVP product refining tower condenser (29), and the output end of the NVP product refining tower full condenser (31) is connected to the middle part of the lightness removal tower (6); The bottom of the NVP product refining tower (7) is connected to the middle of the 2-PY recovery tower (8).

10. The synthesis device of N-vinyl pyrrolidone according to claim 3, characterized in that: The top of the 2-PY recovery tower (8) is matched with a 2-PY recovery tower condenser (33), and the bottom of the 2-PY recovery tower (8) is matched with a 2-PY recovery tower condenser (33); The 2-PY recovery tower condenser (33) is connected to the static mixer (11) so that the recovered 2-PY and fresh 2-PY are mixed at the static mixer (11).

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