Energy saving device for separating nmp and chloroform

Abstract

The utility model belongs to chemical technology field especially relates to a kind of energy-saving device of separation NMP and chloroform. Including preheater, preheating cooler, phase separation tank and de-extraction agent column, NMP, chloroform raw material pipeline is connected preheater after passing through feed pump, and it is connected with the middle part in de-extraction agent column, it is characterized in that, the gas outlet of de-extraction agent column top is connected with a multistage compression cooling structure, de-extraction agent column kettle is connected with a heat pump reboiler, the outlet pipeline of multistage compression cooling structure is connected heat pump reboiler, the outlet pipeline of heat pump reboiler is connected preheater, the outlet pipeline of preheater is connected preheating cooler, the outlet pipeline of preheating cooler is connected phase separation tank. The utility model reduces the consumption of tower kettle steam, recovers the heat of large amount of chloroform in tower top, while reducing the amount of tower top circulating water.

Description

Technical Field

[0001] This utility model belongs to the field of chemical technology, and in particular relates to an energy-saving device for separating NMP and chloroform. Background Technology

[0002] Aramid II, a high-performance fiber material, is widely used in aerospace, defense, and automotive industries. In the production process of aramid II, NMP (nitrogenous polymethyl methacrylate) is an important solvent used to dissolve monomers and form a homogeneous reaction system, ensuring efficient and uniform polymerization. However, NMP is a high-boiling-point, low-volatility organic solvent; its extensive use in the production process not only significantly increases production costs but also poses potential environmental pollution risks. Therefore, the recovery and reuse of NMP solvent is a crucial step in the production of aramid II.

[0003] The main processes for recovering solvent NMP include direct distillation and extractive distillation. Currently, extractive distillation is the primary method due to its high recovery rate and reduced NMP loss. The extractive distillation process mainly includes several steps: extraction, extractant removal, and distillation. The extraction column uses chloroform to extract NMP from water; the extractant removal column separates chloroform and NMP, with chloroform being returned to the upstream section for reuse; and the distillation column further removes water from the NMP.

[0004] The separation of chloroform and NMP is a crucial step in extractive distillation. Conventional distillation methods are generally used to separate NMP and chloroform. While traditional distillation techniques are widely used in solvent recovery, the high boiling point of NMP requires a large heat input to the distillation column, and condensing chloroform gas requires a significant amount of cooling. This results in high energy consumption and low efficiency. Therefore, reducing energy consumption and efficiently recovering the heat from the distillation column top gas are urgent challenges that need to be addressed. Utility Model Content

[0005] The purpose of this invention is to address the above-mentioned problems by providing an energy-saving device for separating NMP and chloroform.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An energy-saving device for separating NMP and chloroform includes a preheater, a preheating cooler, a phase separation tank, and a deextractant tower. The NMP and chloroform feed lines are connected to the preheater via a feed pump and then to the middle of the deextractant tower. The device is characterized in that the gas outlet at the top of the deextractant tower is connected to a multi-stage compression cooling structure, and the bottom of the deextractant tower is connected to a heat pump reboiler. The outlet line of the multi-stage compression cooling structure is connected to the heat pump reboiler, the outlet line of the heat pump reboiler is connected to the preheater, the outlet line of the preheater is connected to the preheating cooler, and the outlet line of the preheating cooler is connected to the phase separation tank.

[0008] In the aforementioned energy-saving device for separating NMP and chloroform, the multi-stage compression and cooling structure includes a first-stage compressor, the inlet of which is connected to the gas outlet at the top of the extractant removal column, the outlet of which is connected to a first-stage cooler, the outlet of which is connected to the inlet of a second-stage compressor, the outlet of which is connected to a second-stage cooler, the outlet of which is connected to the inlet of a third-stage compressor, the outlet of which is connected to a third-stage cooler, and the outlet of which is connected to a heat pump reboiler.

[0009] In the above-mentioned energy-saving device for separating NMP and chloroform, the aqueous phase outlet and oil phase outlet of the phase separation tank are respectively connected to an aqueous phase pump and an oil phase pump, and the outlet of the aqueous phase pump is connected to the upper part of the de-extractant tower.

[0010] In the aforementioned energy-saving device for separating NMP and chloroform, the outlet of the aqueous phase pump is divided into two paths: one path connects to the upper part of the de-extractant tower, and the other path connects to the extraction pipeline.

[0011] In the above-mentioned energy-saving device for separating NMP and chloroform, the bottom of the deextractant tower is connected to a bottom pump, and the outlet of the bottom pump is connected to the NMP collection pipeline.

[0012] In the aforementioned energy-saving device for separating NMP and chloroform, a pressure-reducing valve is installed on the pipeline between the preheating cooler and the phase separation tank.

[0013] In the energy-saving device for separating NMP and chloroform described above, the bottom of the extractant removal column is also equipped with a reboiler.

[0014] Compared with existing technologies, the advantages of this utility model are:

[0015] This reduced the consumption of steam in the column bottom, recovered a large amount of heat from the chloroform at the top of the column, and reduced the amount of circulating water used at the top of the column. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] Figure 2 This is a schematic diagram of existing technology;

[0018] In the diagram: preheater S1, preheating cooler S2, feed pump S3, pressure reducing valve S4, oil phase pump S5, phase separation tank S6, water phase pump S7, bottom pump S8, de-extractant tower S9, heat pump reboiler S10, primary compressor S11, primary cooler S12, secondary compressor S13, secondary cooler S14, tertiary compressor S15, tertiary cooler S16, multi-stage compression and cooling structure 100. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Example 1

[0021] like Figure 1 As shown, this utility model provides an energy-saving device for separating NMP and chloroform, including a preheater S1, a preheating cooler S2, a phase separation tank S6, and a deextractant tower S9. The feed lines containing NMP and chloroform are connected to the preheater S1 via a feed pump S3 and then connected to the middle of the deextractant tower S9. The gas outlet at the top of the deextractant tower S9 is connected to a multi-stage compression cooling structure 100. The bottom of the deextractant tower S9 is connected to a heat pump reboiler S10. The outlet line of the multi-stage compression cooling structure 100 is connected to the heat pump reboiler S10. The outlet line of the heat pump reboiler S10 is connected to the preheater S1. The outlet line of the preheater S1 is connected to the preheating cooler S2. The outlet line of the preheating cooler S2 is connected to the phase separation tank S6.

[0022] Specifically, the multi-stage compression and cooling structure 100 includes a first-stage compressor S11, the inlet of which is connected to the top gas outlet of the extractant removal tower S9, the outlet of which is connected to a first-stage cooler S12, the outlet of which is connected to the inlet of a second-stage compressor S13, the outlet of which is connected to a second-stage cooler S14, the outlet of which is connected to the inlet of a third-stage compressor S15, the outlet of which is connected to a third-stage cooler S16, and the outlet of which is connected to a heat pump reboiler S10.

[0023] The aqueous phase outlet and oil phase outlet of the phase separation tank S6 are respectively connected to the aqueous phase pump S7 and the oil phase pump S5. The outlet of the aqueous phase pump S7 is connected to the upper part of the de-extractant tower S9.

[0024] The outlet of the aqueous phase pump S7 is divided into two paths. One path is connected to the upper part of the de-extractant tower S9 and refluxed back to the de-extractant tower S9. The other path is connected to the collection pipeline and treated as wastewater for further processing.

[0025] The bottom of the extractant removal column S9 is connected to the bottom pump S8, and the outlet of the bottom pump S8 is connected to the NMP production pipeline.

[0026] A pressure reducing valve S4 is installed on the pipeline between the preheating cooler S2 and the phase separation tank S6, and a reboiler S17 is also installed in the bottom of the extractant removal tower S9.

[0027] Based on the above-mentioned energy-saving device for separating NMP and chloroform, this embodiment also provides a method for separating NMP and chloroform. The raw material containing NMP and chloroform is passed through the preheater S1 and then into the de-extractant tower S9. NMP is collected from the bottom of the de-extractant tower S9, and a mixed gas of chloroform and water is collected from the top of the de-extractant tower S9. The mixed gas is compressed by a first-stage compressor S11, cooled by a first-stage cooler S12, compressed by a second-stage compressor S13, cooled by a second-stage cooler S14, compressed by a third-stage compressor S15, and cooled by a third-stage cooler S16. After that, it exchanges heat with the heat pump reboiler S10 at the bottom of the de-extractant tower S9 to heat the liquid at the bottom of the de-extractant tower S9. The mixed gas of chloroform and water after heat exchange is passed into the preheater S1 to heat the raw material containing NMP and chloroform. Then it enters the preheater cooler S2 to cool into a liquid and then enters the phase separation tank S6 for oil-water separation.

[0028] The chloroform in phase separator S6 is collected by oil phase pump S5 and can be sent to the previous process for NMP extraction from water. A portion of the chloroform in phase separator S6 is refluxed to the extractant removal column S9 by water phase pump S7 for reuse, while the other portion is collected as wastewater for further treatment. The NMP in the bottom of the extractant removal column S9 is collected by bottom pump S8 and enters the next distillation process.

[0029] Application Example 1

[0030] Using the apparatus and method of Example 1, taking a 79.5 t / h process as an example, the composition is 87.76% (wt) chloroform, 11.02% (wt) NMP, 0.04% CaCl2, and 1.18% (wt) H2O. The temperature of the gas at the top outlet line G1 of the extractant tower S9 is approximately 80.1°C, and the pressure is 0.005 MPaG. The temperature of the gas at the outlet line G2 of the first-stage compressor S11 is approximately 164.3°C, and the pressure is 0.197 MPaG. The power of the first-stage compressor S11 is approximately 1351.2 kW. The temperature of the gas at the outlet line G3 of the first-stage cooler S12 is approximately 106.7°C, and the pressure is 0.187 MPaG. The load of the first-stage cooler S12 is approximately 0.8366 Gcal / h. The gas temperature at outlet line G4 of the second-stage compressor S13 is approximately 177.9℃, the pressure is 0.563 MPaG, and the power of the second-stage compressor S13 is approximately 1124.1 kW. The gas temperature at outlet line G5 of the second-stage cooler S14 is approximately 132.2℃, the pressure is 0.553 MPaG, and the load on the second-stage cooler S14 is approximately 0.6875 Gcal / h. The gas temperature at outlet line G6 of the third-stage compressor S15 is approximately 173.7℃, the pressure is 0.946 MPaG, and the power of the third-stage compressor S15 is approximately 629.4 kW. The gas temperature at outlet line G7 of the third-stage cooler S16 is approximately 148.2℃, the pressure is 0.936 MPaG, and the load on the third-stage cooler S16 is approximately 0.3934 Gcal / h. The liquid temperature at outlet line G8 of the heat pump reboiler S10 is approximately 137.8℃, the pressure is 0.931 MPaG, and the load on heat pump reboiler S10 is approximately 7.4234 Gcal / h. The liquid temperature at outlet line G9 of the preheater S1 is approximately 85℃, the pressure is 0.921 MPaG, and the load on preheater S1 is approximately 1.7302 Gcal / h. The liquid temperature at outlet line G10 of the preheater cooler S2 is approximately 45℃, the pressure is 0.916 MPaG, and the load on preheater cooler S2 is approximately 1.1167 Gcal / h.The temperature of the liquid at the outlet line G11 of pressure reducing valve S4 is approximately 45℃, and the pressure is 0.005 MPa. The temperature of the liquid containing NMP and chloroform at the inlet line G14 of preheater S1 is approximately 45℃, and the pressure is 0.035 MPa. The temperature of the liquid at the outlet line G15 of preheater S1 is approximately 72℃, and the pressure is 0.03 MPa. The temperature of the liquid in the bottom tank of extractant tower S9 at the outlet line G17 of bottom pump S8 is approximately 134.9℃, and the pressure is 0.3 MPa. The aqueous phase at the outlet line G1 of aqueous phase pump S7... The temperature of the liquid is approximately 45.3℃ and the pressure is 0.3 MPaG. The temperature of the liquid in the oil phase at the outlet pipeline G12 of the oil phase pump S5 is approximately 45.3℃ and the pressure is 0.3 MPaG. The load of the reboiler S17 is approximately 1.1322 Gcal / h, the steam consumption of the reboiler is approximately 2.3 t / h, and the circulating cooling water consumption is approximately 265.1 t / h. The circulating cooling water consumption here includes the total cooling water consumption of the preheating cooler S2, the primary cooler S12, the secondary cooler S14, and the tertiary cooler S16.

[0031] Comparative Example 1

[0032] like Figure 2 As shown, referring to the method of Application Example 1, the first-stage compressor S11, first-stage cooler S12, second-stage compressor S13, second-stage cooler S14, third-stage compressor S15, third-stage cooler S16, heat pump reboiler S10, and pressure reducing valve S4 are eliminated. The top steam line G1 of the extractant removal column S9 is connected to the preheater S1. The load of preheater S1 is approximately 1.7302 Gcal / h. The load of reboiler S17 is approximately 8.5556 Gcal / h, and the steam consumption is approximately 17.4 t / h, an increase of 15.1 t / h, which is approximately 656% higher than in Application Example 1. The load of preheater cooler S2 is approximately 7.7958 Gcal / h, and the circulating cooling water consumption is approximately 779.6 t / h, an increase of 514.5 t / h, which is approximately 194% higher than in Application Example 1. Here, the circulating cooling water consumption refers to the cooling water consumption of preheater cooler S2.

[0033] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model.

Claims

1. An energy-saving device for separating NMP and chloroform, comprising a preheater (S1), a preheating cooler (S2), a phase separation tank (S6), and a deextractant tower (S9), wherein the NMP and chloroform feed lines are connected to the preheater (S1) via a feed pump (S3) and then connected to the middle of the deextractant tower (S9), characterized in that, The gas outlet of the extractant removal tower (S9) is connected to a multi-stage compression cooling structure (100), and the bottom of the extractant removal tower (S9) is connected to a heat pump reboiler (S10). The outlet pipeline of the multi-stage compression cooling structure (100) is connected to the heat pump reboiler (S10), the outlet pipeline of the heat pump reboiler (S10) is connected to the preheater (S1), the outlet pipeline of the preheater (S1) is connected to the preheating cooler (S2), and the outlet pipeline of the preheating cooler (S2) is connected to the phase separation tank (S6).

2. The energy-saving device for separating NMP and chloroform according to claim 1, characterized in that, The multi-stage compression and cooling structure (100) includes a first-stage compressor (S11), the inlet of which is connected to the gas outlet at the top of the deextractant tower (S9), the outlet of which is connected to a first-stage cooler (S12), the outlet of which is connected to the inlet of a second-stage compressor (S13), the outlet of which is connected to a second-stage cooler (S14), the outlet of which is connected to the inlet of a third-stage compressor (S15), the outlet of which is connected to a third-stage cooler (S16), and the outlet of which is connected to a heat pump reboiler (S10).

3. The energy-saving device for separating NMP and chloroform according to claim 1, characterized in that, The phase separation tank (S6) is connected to an aqueous phase pump (S7) and an oil phase pump (S5) at its aqueous phase outlet and oil phase outlet, respectively. The outlet of the aqueous phase pump (S7) is connected to the upper part of the de-extractant tower (S9).

4. The energy-saving device for separating NMP and chloroform according to claim 1, characterized in that, The outlet of the aqueous phase pump (S7) is split into two paths: one path connects to the upper part of the de-extractant tower (S9), and the other path connects to the extraction pipeline.

5. The energy-saving device for separating NMP and chloroform according to claim 1, characterized in that, The bottom of the extractant tower (S9) is connected to a bottom pump (S8), and the outlet of the bottom pump (S8) is connected to the NMP extraction pipeline.

6. The energy-saving device for separating NMP and chloroform according to claim 1, characterized in that, A pressure reducing valve (S4) is installed on the pipeline between the preheating cooler (S2) and the phase separation tank (S6).

7. The energy-saving device for separating NMP and chloroform according to claim 1, characterized in that, The bottom of the extractant removal column (S9) is also equipped with a bottom reboiler (S17).

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