An apparatus for producing 2-pyrrolidone
By combining a three-stage membrane module and a phosphate absorption tower, the problem of incomplete ammonia consumption in the production of 2-pyrrolidone was solved, achieving efficient ammonia recovery and resource utilization, and reducing processing costs and pollution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 宁夏惟远新能源有限公司
- Filing Date
- 2025-08-27
- Publication Date
- 2026-07-21
AI Technical Summary
In the existing 2-pyrrolidone production process, ammonia is not completely consumed and is emitted, resulting in high pollution, high cost and low efficiency.
A combined system of three-stage membrane modules and a phosphoric acid absorption tower is adopted to achieve efficient recovery and resource utilization of ammonia through separation of ammonia-containing waste gas by three-stage membrane modules and treatment of ammonia-containing waste gas by phosphoric acid absorption tower.
It achieved an ammonia recovery rate of over 99%, near-zero emissions of organic amines, reduced treatment costs, and transformed waste gas into high-value resources, thus constructing a closed-loop economic model for waste gas resource utilization.
Smart Images
Figure CN224524785U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical production technology, specifically to a production equipment for 2-pyrrolidone. Background Technology
[0002] In the industrial production of 2-pyrrolidone, the γ-butyrolactone (GBL) ammonolysis method is used. The ammonolysis reaction is achieved by introducing excess ammonia gas into a fixed-bed or batch reactor. The main reactions are shown below: C4H6O2(GBL) + NH3 → C4H7NO(2-pyrrolidone) + H2O This reaction is a reversible equilibrium reaction. At conventional process temperatures (150-250℃), the equilibrium constant K≈0.5-2 (decreases with increasing temperature). In actual production, an excess of ammonia is required (molar ratio NH3:GBL = 2-5:1) to ensure complete GBL conversion. However, the excess ammonia cannot be completely consumed, and 20-30% of the unreacted ammonia escapes with the waste gas. Typical ammonia-containing waste gases include ammonia, nitrogen, water vapor, and organic amines. Ammonia has limited solubility in water (approximately 480 g / L at 25℃), requiring high-flow-rate water circulation, generating a large amount of ammonia-containing wastewater. Unrecovered ammonia needs to be incinerated, wasting energy and increasing CO2 emission costs. Therefore, the existing technology needs further development. Utility Model Content
[0003] This utility model provides a production equipment for 2-pyrrolidone, and the specific implementation method is as follows: A production apparatus for 2-pyrrolidone includes: a material mixing device, a reaction device, a gas-liquid separation device, and a distillation and purification device connected in sequence. The gas outlet of the gas-liquid separation device is connected to a membrane separation system for ammonia-containing waste gas. The membrane separation system for ammonia-containing waste gas includes a first-stage membrane module, a second-stage membrane module, and a third-stage membrane module for ammonia-containing waste gas, which are connected in series.
[0004] Furthermore, the permeate gas from the permeate side of the first-stage membrane module enters the second-stage membrane module, the retentate gas from the retentate side of the second-stage membrane module enters the third-stage membrane module, and the permeate gas from the third-stage membrane module returns to the second-stage membrane module.
[0005] Furthermore, the membrane separation system for ammonia-containing waste gas also includes a phosphoric acid absorption tower, and the permeate gas from the permeate side of the second-stage membrane module enters the phosphoric acid absorption tower.
[0006] Furthermore, the phosphoric acid absorption tower is equipped with an atomizing injector capable of spraying phosphoric acid.
[0007] Furthermore, the feed pressures of the first-stage membrane module, the second-stage membrane module, and the third-stage membrane module are 0.7-0.9 MPa, 1.1-1.3 MPa, and 0.2-0.4 MPa, respectively.
[0008] Furthermore, the first-stage membrane module, the second-stage membrane module, and the third-stage membrane module all include a hollow fiber layer, which sequentially comprises a cross-linked polyamide layer, a polysulfone porous layer, and a fluorosilane hydrophobic layer.
[0009] Furthermore, the gas-liquid separation device is a flash tank.
[0010] Furthermore, the reaction device is a tubular reactor.
[0011] Furthermore, the distillation and purification apparatus includes a light-light-removal tower and a refining tower.
[0012] Beneficial effects: 1. This application includes a membrane separation system for ammonia-containing waste gas. The system separates the gas phase from the gas-liquid separation device through a three-stage membrane structure, achieving direct emission standards. This membrane separation system achieves an ammonia recovery rate >99%, near-zero organic amine emissions (<1 ppm), and reduces the treatment cost per ton of ammonia to 280 yuan. Simultaneously, it converts ammonia-containing waste gas into a high-value resource, completely solving the three major industry pain points of high pollution, high cost, and low efficiency of traditional processes, and constructing a closed-loop economic model for waste gas resource utilization.
[0013] 2. The phosphoric acid absorption tower is equipped with an atomizing injector (5-10μm phosphoric acid solution) that can spray phosphoric acid. The phosphoric acid solution sprayed by the atomizing injector reacts with the ammonia gas permeating from the second-stage membrane module to produce ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate. The solution generated by the reaction is enriched in the conical section at the bottom of the tower and can be recycled as ammonium salt. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of a 2-pyrrolidone production equipment used in an embodiment of this utility model; Figure 2 This is a schematic diagram of the ammonia-containing waste gas treatment process used in an embodiment of this utility model; The above figures include the following reference numerals: 1. Material mixing device; 2. Tubular reactor; 3. Flash tank; 41. First-stage membrane module; 411. First cross-linked polyamide layer; 412. First polysulfone porous layer; 413. First fluorosilane hydrophobic layer; 42. Second-stage membrane module; 421. Second cross-linked polyamide layer; 422. Second polysulfone porous layer; 423. Second fluorosilane hydrophobic layer; 43. Third-stage membrane module; 431. Third cross-linked polyamide layer; 432. Third polysulfone porous layer; 433. Third fluorosilane hydrophobic layer; 5. Phosphoric acid absorption tower; 51. Atomizing injector; 61. Light weight removal tower; 62. Refining tower; 7. Product storage tank. Detailed Implementation
[0015] 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.
[0016] 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.
[0017] According to an embodiment of this utility model, a production apparatus for 2-pyrrolidone is provided. Please refer to [link / reference]. Figures 1 to 2 ,include: A production apparatus for 2-pyrrolidone includes: a material mixing device 1, a reaction device, a gas-liquid separation device, and a distillation and purification device connected in sequence. The gas outlet of the gas-liquid separation device is connected to a membrane separation system for ammonia-containing waste gas. The membrane separation system for ammonia-containing waste gas includes a first-stage membrane module 41, a second-stage membrane module 42, and a third-stage membrane module 43, which are connected in series. The 2-pyrrolidone production apparatus incorporates the membrane separation system for ammonia-containing waste gas, which separates and recycles the gas phase separated from the gas-liquid separation device, reducing the emission of ammonia-containing waste gas. Simultaneously, it converts the ammonia-containing waste gas into a high-value resource, completely solving the three major industry pain points of high pollution, high cost, and low efficiency of traditional processes, and constructing a closed-loop economic model for waste gas resource utilization.
[0018] like Figure 2The permeate gas from the permeate side of the first-stage membrane module 41 enters the second-stage membrane module 42, the retentate gas from the retentate side of the second-stage membrane module 42 enters the third-stage membrane module, and the permeate gas from the third-stage membrane module 43 returns to the second-stage membrane module 42. NH3, due to its polarity, preferentially adsorbs onto the membrane surface. After adsorption, NH3 rapidly diffuses on the membrane surface and then permeates out through the negative pressure on the permeate side of the membrane module; the gas that permeates out becomes the permeate gas. Non-polar gases such as N2 and O2 are not easily adsorbed and cannot permeate through the membrane module, thus being retained; the gas that cannot permeate through the membrane module is called the retentate gas. The three-stage membrane module continuously permeates ammonia from the waste gas, ultimately obtaining high-purity ammonia. The three-stage membrane modules work synergistically: the first-stage membrane module 41 coarsely concentrates and recovers 80% of the ammonia, but the purity is insufficient; the second-stage membrane module 42 obtains high-purity ammonia; and the third-stage membrane module 43 performs final purification, ensuring that the final exhaust gas emission meets standards. The permeate gas from the third-stage membrane module 43 is returned, sending the low-concentration ammonia back to the upstream stage for further treatment, thus avoiding waste and reducing emissions.
[0019] The membrane separation system for ammonia-containing waste gas also includes a phosphoric acid absorption tower 5, through which the permeate gas from the permeate side of the second-stage membrane module 42 enters the phosphoric acid absorption tower 5. The phosphoric acid absorption tower 5 converts the high-purity ammonia gas separated by the membrane into ammonium phosphate salt through a phosphoric acid chemical absorption mechanism. The ammonium phosphate salt enriched in the conical section at the bottom of the phosphoric acid absorption tower 5 can be recycled industrially. Simultaneously, it utilizes the complexation reaction of phosphoric acid to capture escaped impurities such as N-methylpyrrolidone (removal rate > 88.9%). The resource-recoverable ammonium phosphate salt solution generated by the phosphoric acid absorption tower 5 can be further processed as a seed additive to improve the crystal quality of 2-pyrrolidone or as a fertilizer raw material.
[0020] The phosphoric acid absorption tower 5 is equipped with an atomizing injector 51. The atomizing injector 51 in the phosphoric acid absorption tower 5 generates 5-10 μm phosphoric acid droplets, achieving a droplet specific surface area of 1200 m². 2 / m 3 (24 times faster than traditional spraying), shortening the gas-liquid contact time to within 0.2 seconds, resulting in a significant increase in the ammonia absorption rate constant; simultaneously, the atomized phosphoric acid undergoes in-situ ion-pair complexation with residual N-methylpyrrolidone, etc. (generating NMPH). + H2PO4 - This reduces the concentration of organic amines escaping from the membrane from 900 ppm to below 100 ppm, with a rejection rate >88.9%.
[0021] The feed pressures of the first-stage membrane module 41, the second-stage membrane module 42, and the third-stage membrane module 43 are 0.7-0.9 MPa, 1.1-1.3 MPa, and 0.2-0.4 MPa, respectively. The gradient pressure design of the three-stage membrane modules (first stage 0.7-0.9 MPa, second stage 1.1-1.3 MPa, third stage 0.2-0.4 MPa) improves the ammonia recovery rate through the synergistic effect of high-pressure coarse capture in the first-stage membrane module 41, overpressure purification in the second-stage membrane module 42, and low-pressure finishing in the third-stage membrane module 43. The first-stage membrane module 41 operates at a high pressure of 0.7-0.9 MPa, which increases the ammonia diffusion rate and improves the ammonia permeation flux, allowing most of the ammonia to be captured by the first-stage membrane module 41. The second-stage membrane module 42 operates at an ultra-high pressure of 1.1-1.3 MPa, which shortens the free path of gas molecules, resulting in more significant separation of ammonia and nitrogen, producing high-purity ammonia for further purification and recovery. The third-stage membrane module operates at a low pressure of 0.2-0.4 MPa to finally reduce the ammonia concentration in the tail gas. Simultaneously, the first-stage membrane module 41 directly utilizes the residual pressure of the gas-liquid separator, eliminating the need for compression power consumption, and the third-stage membrane module 43 operates at low pressure, reducing vacuum energy consumption by 60%, thus drastically reducing the overall energy consumption per ton of ammonia from 420 kWh to 180 kWh.
[0022] The first-stage membrane module 41, the second-stage membrane module 42, and the third-stage membrane module 43 all include hollow fiber layers, which sequentially comprise a cross-linked polyamide layer, a polysulfone porous layer, and a fluorosilane hydrophobic layer. The first-stage membrane module 41 includes a first cross-linked polyamide layer 411, a first polysulfone porous layer 412, and a first fluorosilane hydrophobic layer 413. The second-stage membrane module 42 includes a second cross-linked polyamide layer 421, a second polysulfone porous layer 422, and a second fluorosilane hydrophobic layer 423. The third-stage membrane module 43 includes a third cross-linked polyamide layer 431, a third polysulfone porous layer 432, and a third fluorosilane hydrophobic layer 433.
[0023] The cross-linked polyamide separation layer achieves an ammonia / nitrogen selectivity >200 and an ammonia permeation flux of 15 L / (m²·h·bar) through the strong polar adsorption of ammonia by amide groups and the 0.34 nm molecular channels formed by the cross-linked network. Simultaneously, the cross-linked structure completely blocks membrane pore deformation caused by the swelling of organic amines (such as NMP). The polysulfone porous support layer, with its bicontinuous microporous structure, withstands high pressure without creep, exhibiting burst strength twice the industry average, and increases the ammonia diffusion rate to 2.1 × 10⁻⁶ through its interconnected channels. -6 cm² / s; a fluorosilane hydrophobic coating forms a nanoscale air cushion barrier, preventing organic amine droplets from wetting the membrane surface. Combined with a 28kHz ultrasonic transducer, it achieves zero-adhesion self-cleaning. These three elements synergistically improve membrane lifespan, achieving 99% ammonia recovery and withstanding 5000ppm organic amine shocks.
[0024] The gas-liquid separation device is a flash tank 3. The flash tank 3 separates the liquid phase containing 2-pyrrolidone and the gas phase containing ammonia by a sudden pressure drop (2.5MPa→0.3MPa), achieving efficient gas-liquid separation.
[0025] The reaction apparatus is a tubular reactor 2. Tubular reactor 2 is the main site of the reaction, in which the following reaction occurs: C4H6O2(GBL) + NH3 → C4H7NO(2-pyrrolidone) + H2O The distillation and purification unit includes a light component removal column 61 and a refining column 62. The light component removal column 61 selectively removes light components: under a negative pressure of -50 kPa and a top temperature of 60°C, light components with boiling points <150°C (residual ammonia, water, methylamine, etc. in the crude liquid product) are separated from the top of the column, with an ammonia recovery rate >99% (returned to the synthesis section). Simultaneously, crude 2-pyrrolidone with a water content <0.1% is collected via a side stream to avoid product hydrolysis caused by aqueous phase entrainment. The refining column 62, under an ultimate vacuum of 1.5 kPa and a bottom temperature of 185°C, deeply retains high-boiling-point substances (dimers, tar), and collects refined 2-pyrrolidone from the top. The collected 2-pyrrolidone is transported via pipeline to the product storage tank 7.
[0026] The specific process is as follows: The reactants enter the mixing device 1 through the inlet, where γ-butyrolactone (GBL), liquid ammonia, and ammonia water are initially mixed. The mixture then enters the tubular reactor 2 for reaction, yielding the crude product 2-pyrrolidone. However, the reaction is reversible, and the crude product still contains ammonia, GBL, and other components. The crude product is then separated into gas and liquid phases by a flash evaporator 3. The gas phase enters a membrane separation system, while the liquid phase enters a distillation unit.
[0027] The gas phase first enters the first-stage membrane module 41, with a feed pressure of 0.7-0.9 MPa. Within the first-stage membrane module 41, the gas sequentially passes through a first cross-linked polyamide layer 411, a first polysulfone porous layer 412, and a first fluorosilane hydrophobic layer 413. The permeate gas permeating through the first-stage membrane module 41 enters the second-stage membrane module 42. The retained gas in the first-stage membrane module 41 undergoes secondary recompression. The permeate gas permeating through the first-stage membrane module 41 then enters the second-stage membrane module 42, with a feed pressure of 1.1-1.3 MPa. Within the second-stage membrane module 42, the gas sequentially passes through a second cross-linked polyamide layer 421, a second polysulfone porous layer 422, and a second fluorosilane hydrophobic layer 423. The permeate gas permeating through the second-stage membrane module 42 enters the phosphoric acid absorption tower 5. The retained gas in the second-stage membrane module 42 flows into the third-stage membrane module 43. The feed pressure of the third-stage membrane module 43 is 0.2-0.4 MPa. The trapped gas retained by the second-stage membrane module 42 passes sequentially through the third cross-linked polyamide layer 431, the third polysulfone porous layer 432, and the third fluorosilane hydrophobic layer 433 in the third-stage membrane module 43. The permeate gas of the third-stage membrane module 43 returns to the second-stage membrane module 42. The exhaust gas meets the emission standards and is discharged into the outside.
[0028] The liquid phase enters the distillation unit, which includes a light component removal column 61 and a purification column 62. The crude liquid product first enters the light component removal column 61, where it removes light components (such as residual ammonia and water) from the crude product and separates them from the top of the column. Simultaneously, crude 2-pyrrolidone is collected from the top of the column. The purification column 62, operating under an ultimate vacuum of 1.5 kPa and a bottom temperature of 185°C, deeply retains high-boiling-point substances (dimers, tar), and purified 2-pyrrolidone is collected from the top of the column. The collected purified 2-pyrrolidone is transported via pipeline to the product storage tank 7.
[0029] Many other changes and modifications can be made without departing from the concept and scope of this utility model. It should be understood that this utility model is not limited to the specific embodiments, and the scope of this utility model is defined by the appended claims.
Claims
1. A production apparatus for 2-pyrrolidone, characterized in that, The device includes a material mixing device, a reaction device, a gas-liquid separation device, and a distillation and purification device connected in sequence. The gas outlet of the gas-liquid separation device is connected to a membrane separation system for ammonia-containing waste gas. The membrane separation system for ammonia-containing waste gas contains a first-stage membrane module, a second-stage membrane module, and a third-stage membrane module, which are connected in series.
2. The production equipment for 2-pyrrolidone according to claim 1, characterized in that, The permeate gas from the permeate side of the first-stage membrane module enters the second-stage membrane module, the retentate gas from the retentate side of the second-stage membrane module enters the third-stage membrane module, and the permeate gas from the third-stage membrane module returns to the second-stage membrane module.
3. The 2-pyrrolidone production equipment according to claim 2, characterized in that, The membrane separation system for ammonia-containing waste gas also includes a phosphoric acid absorption tower, and the permeate gas from the permeate side of the second-stage membrane module enters the phosphoric acid absorption tower.
4. The 2-pyrrolidone production equipment according to claim 3, characterized in that, The phosphoric acid absorption tower is equipped with an atomizing injector that can spray phosphoric acid.
5. The production equipment for 2-pyrrolidone according to claim 1, characterized in that, The feed pressures of the first-stage membrane module, the second-stage membrane module, and the third-stage membrane module are 0.7-0.9 MPa, 1.1-1.3 MPa, and 0.2-0.4 MPa, respectively.
6. The production equipment for 2-pyrrolidone according to claim 1, characterized in that, The first-stage membrane module, the second-stage membrane module, and the third-stage membrane module all include a hollow fiber layer, which sequentially includes a cross-linked polyamide layer, a polysulfone porous layer, and a fluorosilane hydrophobic layer.
7. The production equipment for 2-pyrrolidone according to claim 1, characterized in that, The gas-liquid separation device is a flash tank.
8. The production equipment for 2-pyrrolidone according to claim 1, characterized in that, The reaction device is a tubular reactor.
9. The production equipment for 2-pyrrolidone according to claim 1, characterized in that, The distillation and purification unit includes a light-light-removal tower and a refining tower.