Refining device for high-water-content crude methanol

Abstract

The utility model provides a high-water-content crude methanol refining device which comprises a pre-rectifying tower, a dehydration rectifying tower, a negative pressure rectifying tower, a first rectifying tower and a second rectifying tower, the top of the dehydration rectifying tower is connected with a dehydration tower reboiler through a dehydration tower gas phase extraction pipeline, and a compressor is arranged on the dehydration tower gas phase extraction pipeline; the output end of the dehydrating tower reboiler is connected with a dehydrating tower return tank, a dehydrating tower return tank extraction pipeline is arranged at the bottom of the dehydrating tower return tank and is respectively connected with a dehydrating tower return pipeline and a negative pressure tower feeding pipeline, and the dehydrating tower return pipeline is connected with the upper part of the dehydrating rectifying tower; the negative pressure tower feeding pipeline is connected with the negative pressure rectifying tower; according to the invention, high-water-content crude methanol can be refined, the precision of a final methanol product is ensured, the unit consumption of steam is less than or equal to 0.7 t steam / t refined methanol while the methanol product is greater than 99.99%, the steam consumption of the system is reduced, and multi-stage utilization of energy and heat coupling are realized.

Description

Technical Field

[0001] The present application relates to the technical field of crude methanol refining, and in particular to a crude methanol refining device with a high water content. Background Art

[0002] The coal chemical industry plays an important role in the sustainable utilization of China's energy. New coal chemical industry is facing new market demands and development opportunities in China. Methanol downstream products such as coal-to-olefins will usher in rapid development. In order to make the refining of high-water content crude alcohol more outstanding in terms of economy, efficiency and energy saving, and to adapt to the unstable fluctuations of the market, to achieve the goal of the best quality of AA-grade methanol products, the lowest energy consumption and the greatest economic benefits, it is necessary to achieve energy conservation and controllability with the smallest investment. The current production process mainly removes the light components in methanol through a stabilization tower or a pre-tower, and then sends it to the methanol distillation unit. The energy consumption and investment are relatively high, and the energy consumption of producing one ton of refined methanol is about 1.5 tons of steam. With the development of technology, some existing technologies can achieve lower energy consumption per ton of refined methanol, but are only applicable to crude methanol with low water content, and the purity of the methanol finally obtained in this technology is low. The closest existing technologies are retrieved as follows:

[0003] Patent application number CN202310877976.6 is a five-tower four-effect crude methanol refining process and equipment, in which the equipment includes a pre-distillation tower, a negative pressure distillation tower, a pressurized distillation tower, an atmospheric distillation tower, and a recovery tower. It adopts a combination of thermal coupling and heat pump. For the existing market, it can achieve the purpose of expanding the capacity of the traditional three-tower methanol distillation process by more than 30%, while reducing steam consumption by 45%-50%; for the new market, it has small investment and strong operability. It adopts energy-saving measures such as heat exchange network optimization and heat recovery, which greatly reduces steam consumption. The consumption per ton of methanol can be reduced to less than 0.5 tons of steam; the application can achieve per ton of methanol consumption It can be reduced to less than 0.5 tons of steam to ensure very low steam consumption. However, the methanol is not dehydrated in this application and is only suitable for processing crude methanol with low water content. The purity of the methanol obtained from the treatment of crude methanol with high water content is relatively low. Example 2 of the application specification mentions: Crude methanol with a water content of 3.8%, after being treated by the equipment and process of this application, the purity of the methanol product is >99.95, and the ethanol content is 30-70ppm. It can be seen that when the water content of crude methanol is greater than 3.8%, the purity of the methanol product will be lower. Therefore, this application can only ensure that a relatively high purity of the methanol product is obtained after the treatment of crude methanol with low water content.

[0004] In summary, it is necessary to provide a device that can purify crude methanol with a high water content, thereby ensuring a higher purity of the methanol product and minimizing steam consumption. Summary of the invention

[0005] The present application provides a crude methanol refining device with a high water content, comprising a pre-distillation tower, a dehydration distillation tower, a negative pressure distillation tower, a distillation tower 1, and a distillation tower 2 which are connected in sequence, wherein a dehydration tower gas phase extraction pipeline is arranged on the top of the dehydration distillation tower, the dehydration tower gas phase extraction pipeline is connected to a dehydration tower reboiler, a compressor is arranged on the dehydration tower gas phase extraction pipeline, the output end of the dehydration tower reboiler is connected to a dehydration tower reflux tank through a dehydration tower reboiler output pipeline, a dehydration tower top condenser is arranged on the dehydration tower reboiler output pipeline, a dehydration tower reflux tank extraction pipeline is arranged at the bottom of the dehydration tower reflux tank, the dehydration tower reflux tank extraction pipeline is respectively connected to a dehydration tower reflux pipeline and a negative pressure tower feed pipeline, the dehydration tower reflux pipeline is connected to the upper part of the dehydration distillation tower, and the negative pressure tower feed pipeline is connected to the negative pressure distillation tower.

[0006] As a preferred solution, the dehydration tower reboiler output pipeline passes through the pre-tower steam reboiler.

[0007] As a preferred scheme, the top of the pre-distillation tower is connected to the negative pressure tower reboiler one through the pre-tower top extraction pipeline, the output end of the negative pressure tower reboiler one is connected to the pre-tower buffer tank through the negative pressure tower reboiler one output pipeline, a pre-tower reflux pipeline is arranged at the bottom of the pre-tower buffer tank, an extraction water pipeline is arranged on one side of the pre-tower buffer tank, and a pre-tower buffer tank gas phase extraction pipeline is arranged on the upper part of the pre-tower buffer tank.

[0008] As a preferred scheme, the bottom of the pre-distillation tower is connected to the dehydration distillation tower through a pre-tower kettle extraction pipeline, and the pre-tower kettle extraction pipeline is provided with a pre-tower kettle pump and a dehydration tower feed preheater. The kettle of the dehydration distillation tower extracts wastewater through the dehydration tower kettle extraction pipeline, and the dehydration tower kettle extraction pipeline passes through the dehydration tower feed preheater.

[0009] As a preferred solution, the dehydration distillation tower is a negative pressure distillation tower or a normal pressure distillation tower.

[0010] As a preferred scheme, the top of the negative pressure distillation tower is connected to the negative pressure tower reflux tank through the negative pressure tower top extraction pipeline, the negative pressure tower top extraction pipeline is provided with a negative pressure tower top condenser, the lower part of the negative pressure tower reflux tank is provided with a negative pressure tower reflux tank liquid phase pipeline, the negative pressure tower reflux tank liquid phase pipeline is provided with a negative pressure tower reflux pump, the negative pressure tower reflux tank liquid phase pipeline is respectively connected to the negative pressure tower reflux pipeline and the negative pressure tower refined methanol extraction pipeline, the negative pressure tower reflux pipeline is connected to the upper part of the negative pressure distillation tower; the upper part of the negative pressure tower reflux tank is provided with a negative pressure tower reflux tank gas phase extraction pipeline, and the negative pressure tower reflux tank gas phase extraction pipeline is provided with a negative pressure tower top secondary condenser and a vacuum pump.

[0011] As a preferred solution, the refined methanol production pipeline of the negative pressure tower is connected to the refined methanol tank.

[0012] As a preferred solution, the first and second distillation towers are respectively an atmospheric distillation tower and a pressurized distillation tower, the top of the atmospheric distillation tower is connected to the second negative pressure tower reboiler through an atmospheric pressure tower gas phase extraction pipeline, the output end of the second negative pressure tower reboiler is connected to the atmospheric pressure tower reflux tank, the bottom of the atmospheric pressure tower reflux tank is provided with an atmospheric pressure tower reflux tank liquid phase extraction pipeline, the atmospheric pressure tower reflux tank liquid phase extraction pipeline is respectively connected to the atmospheric pressure tower reflux pipeline and the atmospheric pressure tower refined methanol extraction pipeline, the atmospheric pressure tower reflux pipeline is connected to the atmospheric pressure tower reflux pipeline, and the atmospheric pressure tower refined methanol extraction pipeline is connected to the atmospheric pressure tower reflux pipeline. The top of the pressurized distillation tower is connected to the pre-tower reboiler and the atmospheric pressure tower reboiler through the pressurized tower gas phase extraction pipeline, the output end of the pre-tower reboiler and the output end of the atmospheric pressure tower reboiler are respectively connected to the pressurized tower reflux tank, and the bottom of the pressurized tower reflux tank is provided with a pressurized tower reflux tank liquid phase extraction pipeline, the pressurized tower reflux tank liquid phase extraction pipeline is respectively connected to the pressurized tower reflux pipeline and the pressurized tower refined methanol extraction pipeline, wherein the pressurized tower reflux pipeline is connected to the upper part of the pressurized distillation tower.

[0013] As a preferred solution, the atmospheric tower refined methanol production pipeline is connected to the refined methanol tank.

[0014] As a preferred solution, the refined methanol production pipeline of the pressurized tower is connected to the refined methanol tank.

[0015] As a preferred solution, the bottom of the negative pressure distillation tower is connected to the atmospheric pressure distillation tower through a negative pressure tower bottom extraction pipeline, and the negative pressure tower bottom extraction pipeline is provided with a negative pressure tower bottom pump and an atmospheric pressure tower feed preheater.

[0016] As a preferred embodiment, the bottom of the atmospheric distillation tower is connected to the pressurized distillation tower through an atmospheric tower kettle extraction pipeline, and the atmospheric tower kettle extraction pipeline is provided with an atmospheric tower kettle pump, a pressurized tower first-level feed preheater, and a pressurized tower second-level feed preheater. The kettle of the pressurized distillation tower is provided with a pressurized tower kettle extraction pipeline, the pressurized tower kettle extraction pipeline extracts wastewater, and the pressurized tower kettle extraction pipeline passes through the pressurized tower first-level feed preheater.

[0017] As a preferred solution, the steam pipeline passes through the pressure tower reboiler, the pressure tower secondary feed preheater, the atmospheric tower feed preheater, and the pre-tower feed preheater in sequence, and the output end of the pre-tower feed preheater is connected to the condensate pipeline.

[0018] As a preferred solution, the first and second distillation towers are respectively pressurized distillation towers and atmospheric distillation towers. The top of the pressurized distillation tower is connected to the pre-tower reboiler and the atmospheric tower reboiler through a pressurized tower gas phase extraction pipeline. The output ends of the pre-tower reboiler and the atmospheric tower reboiler are both connected to the pressurized tower reflux tank. The bottom of the pressurized tower reflux tank is provided with a pressurized tower reflux tank liquid phase extraction pipeline. The pressurized tower reflux tank liquid phase extraction pipeline is respectively connected to the pressurized tower reflux pipeline and the pressurized tower refined methanol extraction pipeline. The pressure tower reflux pipeline is connected to the middle and upper part of the pressure distillation tower; the top of the atmospheric distillation tower is connected to the negative pressure tower reboiler 2 through the atmospheric pressure tower gas phase extraction pipeline, the output ends of the negative pressure tower reboiler 2 are respectively connected to the atmospheric pressure tower reflux tank, and the bottom of the atmospheric pressure tower reflux tank is provided with an atmospheric pressure tower reflux tank liquid phase extraction pipeline, the atmospheric pressure tower reflux tank liquid phase extraction pipeline is respectively connected to the atmospheric pressure tower reflux pipeline and the atmospheric pressure tower refined methanol extraction pipeline, wherein the atmospheric pressure tower reflux pipeline is connected to the upper part of the atmospheric distillation tower.

[0019] As a preferred solution, the atmospheric tower refined methanol production pipeline is connected to the refined methanol tank.

[0020] As a preferred solution, the refined methanol production pipeline of the pressurized tower is connected to the refined methanol tank.

[0021] As a preferred scheme, the bottom of the negative pressure distillation tower is connected to the pressurized distillation tower through a negative pressure tower bottom extraction pipeline, and the negative pressure tower bottom extraction pipeline is provided with a negative pressure tower bottom pump, a pressurized tower first-level feed preheater, and a pressurized tower second-level feed preheater. The bottom of the pressurized distillation tower is provided with a pressurized tower bottom extraction pipeline, and the pressurized tower bottom extraction pipeline is connected to the middle and upper part of the atmospheric distillation tower, and the pressurized tower bottom extraction pipeline passes through the pressurized tower first-level feed preheater.

[0022] As a preferred solution, the steam pipeline passes through the pressure tower reboiler, the pressure tower secondary feed preheater, and the pre-tower feed preheater in sequence, and the output end of the pre-tower feed preheater is connected to the condensate pipeline.

[0023] In the present application, a dehydration distillation tower is provided, so that crude methanol with high water content can be refined. The energy at the top of the dehydration distillation tower is fully recycled and utilized through a compressor (heat pump) to provide heat to the dehydration tower reboiler to heat the distillate in the dehydration distillation tower kettle. The material after heat exchange with the dehydration tower reboiler is not directly extracted, nor directly enters the negative pressure distillation tower, but is processed by the dehydration tower reflux tank, and part of it is refluxed to the dehydration distillation tower, and part of it enters the negative pressure distillation tower, so as to further ensure the accuracy of subsequent distillation, and then ensure the accuracy of the final methanol product; more preferably, the material in the dehydration distillation tower kettle goes to the dehydration tower feed preheater, so as to provide the heat required for heating the material for the dehydration tower feed preheater, thereby further saving The consumption of external steam makes full use of the heat of the materials in the bottom of the dehydration distillation tower; the low-grade heat at the top of the dehydration distillation tower is converted into high-grade heat to meet the heat demand of the reboiler of the dehydration tower; for crude methanol with a water content of 35%, the methanol content can reach 91% after dehydration, and the purity of methanol after refining is 99.99%, the ethanol content in the refined methanol is ≤50ppm, and the methanol content in the wastewater is ≤10ppm, which can meet the discharge standards; it overcomes the problem of using a pre-tower to remove light, the bottom liquid directly enters the dehydration tower for distillation and dehydration, the energy consumption is extremely high, and the feed crude alcohol generally fluctuates. Through the improvement of the present application, the subsequent distillation accuracy problem can be guaranteed, and the technical transformation is convenient, the energy consumption is reduced, and the investment is reduced.

[0024] In addition, this application also has the following advantages:

[0025] 1. The steam at the top of the pre-distillation tower is used to heat the reboiler of the negative pressure tower, providing the heat required for distillation for the negative pressure distillation tower, making full use of the heat of the steam at the top of the pre-distillation tower, saving the steam of the negative pressure distillation tower and reducing the steam consumption of the system; the top of the pre-distillation tower does not need to be cooled by circulating water, saving a lot of circulating water;

[0026] 2. Make full use of the steam heat at the top of the distillation tower 1 and the distillation tower 2. When the distillation tower 1 and the distillation tower 2 respectively use an atmospheric distillation tower and a pressurized distillation tower, the steam at the top of the atmospheric distillation tower provides heat for the negative pressure tower reboiler 2, and then provides the heat required for distillation for the negative pressure distillation tower. The heat at the top of the atmospheric distillation tower is utilized, saving the steam of the negative pressure distillation tower; the steam at the top of the pressurized distillation tower provides heat for the pre-tower reboiler and the atmospheric tower reboiler, and then provides the heat required for distillation for the pre-distillation tower and the atmospheric distillation tower, saving the steam of the atmospheric distillation tower and the pre-distillation tower. Only the pressurized distillation tower uses steam in the whole process, and the tops of the pressurized distillation tower, the atmospheric distillation tower and the pre-distillation tower do not need to be cooled by circulating water, saving a large amount of circulating water;

[0027] When the first distillation tower and the second distillation tower adopt a pressurized distillation tower and an atmospheric distillation tower respectively, the steam at the top of the pressurized distillation tower provides heat for the pre-tower reboiler and the atmospheric distillation tower reboiler, and then provides the heat required for distillation for the pre-distillation tower and the atmospheric distillation tower, and the heat at the top of the pressurized distillation tower is utilized, saving the steam of the pre-distillation tower and the atmospheric distillation tower; the steam at the top of the atmospheric distillation tower provides heat for the second negative pressure tower reboiler, and then provides the heat required for distillation for the negative pressure distillation tower, and the heat at the top of the atmospheric distillation tower is utilized, saving the steam of the negative pressure distillation tower; only the pressurized distillation tower uses steam in the whole process, and the tops of the pressurized distillation tower, the atmospheric distillation tower and the pre-distillation tower do not need to be cooled by circulating water, saving a large amount of circulating water;

[0028] 3. Make full use of the waste heat of the system and the waste heat of the steam condensate. When the first and second distillation towers are atmospheric distillation towers and pressurized distillation towers respectively, the material in the kettle of the pressurized distillation tower provides heat for the first-level feed preheater of the pressurized tower, and the steam is successively provided to the reboiler of the pressurized tower, the second-level feed preheater of the pressurized tower, the atmospheric tower feed preheater, and the pre-tower feed preheater, and then extracted as condensate; that is, the second-level feed preheater of the pressurized tower uses the steam condensate of the pressurized tower reboiler for preheating, the atmospheric tower feed preheater uses the steam condensate of the second-level feed preheater of the pressurized tower for preheating, and the pre-tower feed preheater uses the steam condensate of the atmospheric tower feed preheater for preheating, thereby reducing steam consumption;

[0029] When the first and second distillation towers are pressurized distillation towers and atmospheric distillation towers, respectively, the materials in the kettle of the pressurized distillation tower go to the first-level feed preheater of the pressurized tower to provide the heat required for heating the materials for the first-level feed preheater of the pressurized tower, and then enter the atmospheric distillation tower; the steam is sequentially provided with heat for the reboiler of the pressurized tower, the second-level feed preheater of the pressurized tower, and the feed preheater of the pre-tower, and then extracted as condensate, that is, the second-level feed preheater of the pressurized tower is preheated with the steam condensate of the reboiler of the pressurized tower, and the feed preheater of the pre-tower is preheated with the steam condensate of the second-level feed preheater of the pressurized tower, thereby reducing the consumption of steam;

[0030] 4. This application makes full use of the heat at the top of each tower and the waste heat of the condensate and steam condensate in the tower bottom to ensure that the methanol product is greater than 99.99%, while the steam unit consumption is ≤0.7t steam / t refined alcohol, which greatly reduces the steam consumption of the system and realizes multi-level energy utilization and heat coupling;

[0031] 5. The water content and alcohol content in the refined methanol obtained by the present application can be freely regulated, and the wastewater can be discharged in compliance with the standards without the need for further treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the first embodiment of the present application;

[0033] Figure 2It is a structural diagram of the second embodiment of the present application;

[0034] 1. Pre-tower feed preheater; 2. Pre-distillation tower; 3. Negative pressure tower reboiler 1; 4. Negative pressure distillation tower; 5. Pre-tower buffer tank; 6. Gas phase extraction pipeline; 7. Dehydration distillation tower; 8. Dehydration tower feed preheater; 9. Compressor; 10. Dehydration tower reboiler; 11. Pre-tower steam reboiler; 12. Dehydration tower top condenser; 13. Dehydration tower reflux tank; 14. Atmospheric pressure tower feed preheater; 15. Atmospheric pressure distillation tower; 16. Negative pressure tower reboiler 2; 17. Atmospheric pressure tower reflux tank; 18. Refined methanol tank; 19. Pressure tower primary feed preheater; 2 0. Secondary feed preheater for pressure tower; 21. Pressure distillation tower; 22. Pre-tower reboiler; 23. Pressure tower reflux tank; 24. Atmospheric tower reboiler; 25. Pressure tower reboiler; 26. Pre-tower kettle extraction pipeline; 27. Pre-tower kettle pump; 28. Negative pressure tower kettle extraction pipeline; 29. ​​Negative pressure tower kettle pump; 30. Atmospheric pressure tower kettle extraction pipeline; 31. Atmospheric pressure tower kettle pump; 32. Pressure tower kettle extraction pipeline; 33. Dehydration tower gas phase extraction pipeline; 34. Dehydration tower reboiler output pipeline; 35. Dehydration tower reflux tank extraction pipeline; 36. Dehydration Water tower reflux pump; 37, dehydration tower reflux pipeline; 38, negative pressure tower feed pipeline; 39, pre-tower top extraction pipeline; 40, negative pressure tower reboiler one output pipeline; 41, pre-tower reflux pipeline; 42, pre-tower reflux pump; 43, extraction water pipeline; 44, atmospheric tower gas phase extraction pipeline; 45, negative pressure tower top extraction pipeline; 46, negative pressure tower reflux tank; 47, negative pressure tower top condenser; 48, negative pressure tower reflux tank liquid phase pipeline; 49, negative pressure tower reflux pump; 50, negative pressure tower reflux pipeline; 51, negative pressure tower refined methanol extraction pipeline; 52, negative pressure tower Reflux tank gas phase production pipeline; 53, atmospheric tower reflux tank liquid phase production pipeline; 54, atmospheric tower reflux pump; 55, atmospheric tower reflux pipeline; 56, atmospheric tower refined methanol production pipeline; 57, pressure tower gas phase production pipeline; 58, pressure tower reflux tank liquid phase production pipeline; 59, pressure tower reflux pump; 60, pressure tower reflux pipeline; 61, pressure tower refined methanol production pipeline; 62, steam pipeline; 63, condensate pipeline; 64, pressure tower kettle pump; 65, dehydration tower kettle production pipeline; 66, negative pressure tower top secondary condenser; 67, vacuum pump. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1 , Attachment Figure 2 The specific implementation of the present invention is described in detail. It should be noted that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0036] Embodiment 1:

[0037] The present embodiment provides a crude methanol refining device with a high water content, comprising a pre-distillation tower 2, a dehydration distillation tower 7, a negative pressure distillation tower 4, a distillation tower 1, and a distillation tower 2 connected in sequence. Preferably, the dehydration distillation tower 7 adopts a negative pressure distillation tower or an atmospheric distillation tower. In the present embodiment, the distillation tower 1 and the distillation tower 2 respectively adopt an atmospheric distillation tower 15 and a pressurized distillation tower 21. The lower part of the pre-distillation tower 2 is provided with a pre-tower steam reboiler 11 and a pre-tower reboiler 22. The lower part of the dehydration distillation tower 7 is provided with a dehydration tower reboiler 10. The lower part of the negative pressure distillation tower 4 is provided with a negative pressure tower reboiler 13 and a negative pressure tower reboiler 2 16. The lower part of the atmospheric distillation tower 15 is provided with an atmospheric pressure tower reboiler 24. The lower part of the pressurized distillation tower 21 is provided with a pressurized tower reboiler 25.

[0038] The bottom of the pre-distillation tower 2 is connected to the dehydration distillation tower 7 through the pre-tower kettle extraction pipeline 26, and the dehydration distillation tower 7 dehydrates the crude methanol and can process crude methanol with high water content; the pre-tower kettle extraction pipeline 26 is provided with a pre-tower kettle pump 27 and a dehydration tower feed preheater 8; the top of the dehydration distillation tower 7 is provided with a dehydration tower gas phase extraction pipeline 33, the dehydration tower gas phase extraction pipeline 33 is connected to the dehydration tower reboiler 10, and the dehydration tower gas phase extraction pipeline 33 is provided with a compressor 9. The gas phase at the top of the dehydration distillation tower 7 is pressurized and heated by the compressor 9 to provide heat for the dehydration tower reboiler 10, and the output end of the dehydration tower reboiler 10 is connected to the dehydration tower reboiler 10 by the dehydration tower reboiler. The dehydration tower reboiler output pipeline 34 is connected to the dehydration tower reflux tank 13, and the dehydration tower top condenser 12 is arranged on the dehydration tower reboiler output pipeline 34. Preferably, the dehydration tower reboiler output pipeline 34 passes through the pre-tower steam reboiler 11, and the material in the bottom of the dehydration distillation tower 7 goes to the dehydration tower feed preheater 8, providing the heat required for heating the material for the dehydration tower feed preheater 8, further saving the consumption of external steam and making full use of the heat of the material in the bottom of the dehydration distillation tower 7; the dehydration tower reflux tank extraction pipeline 35 is arranged at the bottom of the dehydration tower reflux tank 13, and the dehydration tower reflux tank extraction pipeline 35 is provided with a dehydration tower reflux pump 36, and the dehydration tower reflux tank extraction pipeline 3 5 are respectively connected to the dehydration tower reflux pipeline 37 and the negative pressure tower feed pipeline 38, wherein the dehydration tower reflux pipeline 37 is connected to the upper part of the dehydration distillation tower 7, and the negative pressure tower feed pipeline 38 is connected to the negative pressure distillation tower 4; the pre-distillation tower 2 kettle extracts waste water through the dehydration tower kettle extraction pipeline 65, and the dehydration tower kettle extraction pipeline passes through the dehydration tower feed preheater 8, and the material in the pre-distillation tower 2 kettle is preheated by the dehydration tower feed preheater 8 and then enters the dehydration distillation tower 7, and the gas phase at the top of the dehydration distillation tower 7 is pressurized and heated by the compressor 9 to provide heat for the dehydration tower reboiler 10 and the pre-tower steam reboiler 11 in turn, and then enters after condensation by the dehydration tower top condenser 12 The dehydration tower reflux tank 13, the liquid phase in the dehydration tower reflux tank 13 is partially refluxed to the dehydration distillation tower 7, and partially enters the negative pressure distillation tower 4; the dehydration distillation tower 7 can refine the crude methanol with high water content, and the energy at the top of the dehydration distillation tower 7 is fully recycled and utilized by the compressor 9, which is used to provide heat to the dehydration tower reboiler 10, and heat the distillate in the bottom of the dehydration distillation tower 7. The material after heat exchange with the dehydration tower reboiler is not directly extracted, nor directly enters the negative pressure distillation tower 4, but is processed by the dehydration tower reflux tank, and partially refluxed to the dehydration distillation tower 7, and partially enters the negative pressure distillation tower 4, so as to further ensure the accuracy of subsequent distillation, and then ensure the accuracy of the final methanol product;

[0039] The top of the negative pressure distillation tower 4 is connected to the negative pressure tower reflux tank 46 through the negative pressure tower top extraction pipeline 45, and a negative pressure tower top condenser 47 is arranged on the negative pressure tower top extraction pipeline 45, and a negative pressure tower reflux tank liquid phase pipeline 48 is arranged at the lower part of the negative pressure tower reflux tank 46, and a negative pressure tower reflux pump 49 is arranged on the negative pressure tower reflux tank liquid phase pipeline 48, and the negative pressure tower reflux tank liquid phase pipeline 48 is respectively connected to the negative pressure tower reflux pipeline 50 and the negative pressure tower refined methanol extraction pipeline 51, wherein the negative pressure tower reflux pipeline 50 is connected to the upper part of the negative pressure distillation tower 4, and the negative pressure tower refined methanol extraction pipeline 51 is connected to the refined methanol tank 18; the upper part of the negative pressure tower reflux tank 46 is provided with a negative pressure tower reflux tank gas phase extraction pipeline 52, and the negative pressure tower reflux tank gas phase extraction pipeline 52 is provided. The outlet pipeline 52 is provided with a secondary condenser 66 and a vacuum pump 67 at the top of the negative pressure tower; the bottom of the negative pressure distillation tower 4 is connected to the atmospheric pressure distillation tower 15 through a negative pressure tower bottom extraction pipeline 28, and a negative pressure tower bottom pump 29 and an atmospheric pressure tower feed preheater 14 are provided on the negative pressure tower bottom extraction pipeline 28; the gas phase at the top of the negative pressure distillation tower 4 enters the negative pressure tower reflux tank 46 after condensation, a part of the liquid phase in the negative pressure tower reflux tank 46 is refluxed to the negative pressure distillation tower 4, and a part is extracted as refined methanol and extracted to the refined methanol tank 18, and the gas phase in the negative pressure tower reflux tank 46 is condensed by the secondary condenser 66 at the top of the negative pressure tower for subsequent treatment; the material in the bottom of the negative pressure distillation tower 4 is preheated by the atmospheric pressure tower feed preheater 14 and then enters the atmospheric pressure distillation tower 15;

[0040] The bottom of the atmospheric distillation tower 15 is connected to the pressurized distillation tower 21 through an atmospheric tower kettle extraction pipeline 30, on which an atmospheric tower kettle pump 31, a pressurized tower primary feed preheater 19, and a pressurized tower secondary feed preheater 20 are provided. The side line of the pressurized distillation tower 21 extracts fusel alcohols. The kettle of the pressurized distillation tower 21 is provided with a pressurized tower kettle extraction pipeline 32, on which a pressurized tower kettle pump 64 is provided. The pressurized tower kettle extraction pipeline 32 extracts wastewater, and the pressurized tower kettle extraction pipeline 32 passes through the pressurized tower primary feed preheater 19. The material extracted from the kettle of the pressurized distillation tower 21 enters the pressurized tower primary feed preheater 19, provides the pressurized tower primary feed preheater 19 with the heat required for heating the material, and then is discharged as wastewater.

[0041] Preferably, this embodiment makes full use of the heat of the top of the pre-distillation tower 2, the distillation tower 1, and the distillation tower 2; the heat of the kettle of the pre-distillation tower 2, the distillation tower 1, and the distillation tower 2; and the waste heat of the steam condensate. Specifically:

[0042] The top of the pre-distillation tower 2 is connected to the negative pressure tower reboiler 3 through the pre-tower top extraction pipeline 39, and the output end of the negative pressure tower reboiler 3 is connected to the pre-tower buffer tank 5 through the negative pressure tower reboiler output pipeline 40. The bottom of the pre-tower buffer tank 5 is provided with a pre-tower reflux pipeline 41, and the pre-tower reflux pipeline 41 is connected to the upper part of the pre-distillation tower 2. The pre-tower reflux pipeline 41 is provided with a pre-tower reflux pump 42. One side of the pre-tower buffer tank 5 is connected to an extraction water pipeline 43, and the upper part of the pre-tower buffer tank 5 is provided with a gas phase extraction pipeline 44. Pipeline 6; the gas phase at the top of the pre-distillation tower 2 exchanges heat with the negative pressure tower reboiler-3, and then enters the pre-tower buffer tank 5, into which extraction water is introduced, and the liquid phase refluxes to the pre-distillation tower 2 through the pre-tower reflux pipeline 41, and the gas phase is extracted through the gas phase extraction pipeline 6; the gas phase at the top of the pre-distillation tower 2 is used to heat the negative pressure tower reboiler-3, so as to make full use of the heat at the top of the pre-distillation tower 2, save the steam of the negative pressure distillation tower 4, and the top of the pre-distillation tower 2 does not need to be cooled by circulating water due to heat exchange, so a large amount of circulating water is saved;

[0043] The top of the atmospheric distillation tower 15 is connected to the negative pressure tower reboiler 16 through the atmospheric pressure tower gas phase extraction pipeline 44, and the output end of the negative pressure tower reboiler 16 is connected to the atmospheric pressure tower reflux tank 17. The bottom of the atmospheric pressure tower reflux tank 17 is provided with an atmospheric pressure tower reflux tank liquid phase extraction pipeline 53, and the atmospheric pressure tower reflux tank liquid phase extraction pipeline 53 is provided with an atmospheric pressure tower reflux pump 54. The atmospheric pressure tower reflux tank liquid phase extraction pipeline 53 is respectively connected to an atmospheric pressure tower reflux pipeline 55 and an atmospheric pressure tower refined methanol extraction pipeline 56. The atmospheric pressure tower reflux pipeline 55 is connected to the upper part of the atmospheric distillation tower 15, and the atmospheric pressure tower refined methanol extraction pipeline 56 is connected to the atmospheric pressure tower refined methanol extraction pipeline 56. The methanol extraction pipeline 56 is connected to the refined methanol tank 18. The gas phase at the top of the atmospheric distillation tower 15 exchanges heat with the negative pressure tower reboiler 2 16 and then enters the atmospheric tower reflux tank 17. Part of the liquid phase of the atmospheric tower reflux tank 17 flows back to the atmospheric distillation tower 15, and part of it is extracted as refined methanol into the refined methanol tank 18. The gas phase at the top of the atmospheric distillation tower 15 is used to heat the negative pressure tower reboiler 2 16, so that the heat at the top of the atmospheric distillation tower 15 is fully utilized, and the steam of the negative pressure distillation tower 4 is saved. Moreover, the top of the atmospheric distillation tower 15 does not need to be cooled by circulating water due to heat exchange, so a large amount of circulating water is saved.

[0044] The top of the pressurized distillation tower 21 is connected to the pre-tower reboiler 22 and the atmospheric tower reboiler 24 respectively through the pressurized tower gas phase extraction pipeline 57, the output ends of the pre-tower reboiler 22 and the atmospheric tower reboiler 24 are respectively connected to the pressurized tower reflux tank 23, and the bottom of the pressurized tower reflux tank 23 is provided with a pressurized tower reflux tank liquid phase extraction pipeline 58, and the pressurized tower reflux tank liquid phase extraction pipeline 58 is provided with a pressurized tower reflux pump 59, and the pressurized tower reflux tank liquid phase extraction pipeline 58 is respectively connected to the pressurized tower reflux pipeline 60 and the pressurized tower refined methanol extraction pipeline 61, wherein the pressurized tower reflux pipeline 60 is connected to the upper part of the pressurized distillation tower 21, and the pressurized tower refined methanol extraction pipeline 61 is connected to the upper part of the pressurized distillation tower 21. The alcohol extraction pipeline 61 is connected to the refined methanol tank 18; the gas phase at the top of the pressurized distillation tower 21 provides heat to the pre-tower reboiler 22 and the atmospheric tower reboiler 24 respectively, and then enters the pressurized tower reflux tank 23, and the liquid phase in the pressurized tower reflux tank 23 is partially refluxed to the pressurized distillation tower 21, and part is extracted as refined methanol to the refined methanol tank 18; the gas phase at the top of the pressurized distillation tower 21 is used to heat the pre-tower reboiler 22 and the atmospheric tower reboiler 24, and the heat at the top of the pressurized distillation tower 21 is fully utilized, saving the steam of the pre-distillation tower 2 and the atmospheric distillation tower 15, and the top of the pressurized distillation tower 21 does not need to be cooled by circulating water through heat exchange, saving a large amount of circulating water;

[0045] The above-mentioned pressure tower reboiler 25 is heated by steam, and the steam pipeline 62 passes through the pressure tower reboiler 25, the pressure tower secondary feed preheater 20, the atmospheric pressure tower feed preheater 14, and the pre-tower feed preheater 1 in sequence. The output end of the pre-tower feed preheater 1 is connected with the condensate pipeline 63, that is, the pressure tower secondary feed preheater 20 adopts the steam condensate of the pressure tower reboiler 25 for preheating, the atmospheric pressure tower feed preheater 14 adopts the steam condensate of the pressure tower secondary feed preheater 20 for preheating, and the pre-tower feed preheater 1 adopts the steam condensate of the atmospheric pressure tower feed preheater 14 for preheating, thereby reducing the consumption of steam.

[0046] Embodiment 2:

[0047] This embodiment provides a crude methanol refining device with high water content. The difference from the first embodiment is that in this embodiment, the first distillation tower and the second distillation tower are respectively a pressure distillation tower 21 and an atmospheric distillation tower 15;

[0048] The bottom of the pre-distillation tower 2 is connected to the dehydration distillation tower 7 through the pre-tower kettle extraction pipeline 26, and the pre-tower kettle extraction pipeline 26 is provided with a pre-tower kettle pump 27 and a dehydration tower feed preheater 8; the top of the dehydration distillation tower 7 is provided with a dehydration tower gas phase extraction pipeline 33, and the dehydration tower gas phase extraction pipeline 33 is connected to the dehydration tower reboiler 10, and the dehydration tower gas phase extraction pipeline 33 is provided with a compressor 9. The gas phase at the top of the dehydration distillation tower 7 is pressurized and heated by the compressor 9 to provide heat for the dehydration tower reboiler 10, and the output end of the dehydration tower reboiler 10 is connected to the dehydration tower reflux tank 13 through the dehydration tower reboiler output pipeline 34. The dehydration tower top condenser 12 is arranged on the dehydration tower reboiler output pipeline 34. Preferably, the dehydration tower reboiler output pipeline 34 passes through the pre-tower steam reboiler 11, and the material in the bottom of the dehydration distillation tower 7 goes to the dehydration tower feed preheater 8, providing the heat required for heating the material for the dehydration tower feed preheater 8, further saving the consumption of external steam and making full use of the heat of the material in the bottom of the dehydration distillation tower 7; the dehydration tower reflux tank 13 is provided with a dehydration tower reflux tank extraction pipeline 35 at the bottom, and a dehydration tower reflux pump 36 is arranged on the dehydration tower reflux tank extraction pipeline 35, and the dehydration tower reflux tank extraction pipeline 35 is respectively connected to the dehydration tower reflux pipeline 37 and the negative pressure tower feed pipeline 38 , wherein the dehydration tower reflux pipeline 37 is connected to the upper part of the dehydration distillation tower 7, and the negative pressure tower feed pipeline 38 is connected to the negative pressure distillation tower 4; the pre-distillation tower 2 kettle extracts wastewater through the dehydration tower kettle extraction pipeline 65, and the dehydration tower kettle extraction pipeline passes through the dehydration tower feed preheater 8, and the material in the kettle of the pre-distillation tower 2 enters the dehydration distillation tower 7 after being preheated by the dehydration tower feed preheater 8, and the gas phase at the top of the dehydration distillation tower 7 is pressurized and heated by the compressor 9 to provide heat for the dehydration tower reboiler 10, and then enters the dehydration tower feed preheater 8 to provide heat for the dehydration tower feed preheater 8, and then enters the dehydration tower reflux tank 13 after condensation through the dehydration tower top condenser 12 , the liquid phase in the dehydration tower reflux tank 13 is partially refluxed to the dehydration distillation tower 7, and partially enters the negative pressure distillation tower 4 to continue distillation; the dehydration distillation tower 7 can refine the crude methanol with high water content, and the energy at the top of the dehydration distillation tower 7 is fully recycled and utilized by the compressor 9 to provide heat to the dehydration tower reboiler 10 to heat the distillate in the bottom of the dehydration distillation tower 7. The material after heat exchange with the dehydration tower reboiler is not directly extracted, nor directly enters the negative pressure distillation tower 4, but is processed by the dehydration tower reflux tank, and partially refluxed to the dehydration distillation tower 7, and partially enters the negative pressure distillation tower 4, so as to further ensure the accuracy of subsequent distillation, and then ensure the accuracy of the final methanol product;

[0049] The top of the negative pressure distillation tower 4 is connected to the negative pressure tower reflux tank 46 through the negative pressure tower top extraction pipeline 45, and a negative pressure tower top condenser 47 is arranged on the negative pressure tower top extraction pipeline 45, and a negative pressure tower reflux tank liquid phase pipeline 48 is arranged at the lower part of the negative pressure tower reflux tank 46, and a negative pressure tower reflux pump 49 is arranged on the negative pressure tower reflux tank liquid phase pipeline 48, and the negative pressure tower reflux tank liquid phase pipeline 48 is respectively connected to the negative pressure tower reflux pipeline 50 and the negative pressure tower refined methanol extraction pipeline 51, wherein the negative pressure tower reflux pipeline 50 is connected to the upper part of the negative pressure distillation tower 4, and the negative pressure tower refined methanol extraction pipeline 51 is connected to the refined methanol tank 18; the upper part of the negative pressure tower reflux tank 46 is provided with a negative pressure tower reflux tank gas phase extraction pipeline 52, and the negative pressure tower reflux tank gas phase extraction pipeline 52 is provided with a negative pressure tower top secondary Condenser 66, vacuum pump 67; the bottom of the negative pressure distillation tower 4 is connected to the pressurized distillation tower 21 through the negative pressure tower bottom extraction pipeline 28, and the negative pressure tower bottom extraction pipeline 28 is provided with a negative pressure tower bottom pump 29, a pressurized tower primary feed preheater 19, and a pressurized tower secondary feed preheater 20; the gas phase at the top of the negative pressure distillation tower 4 enters the negative pressure tower reflux tank 46 after condensation, a part of the liquid phase in the negative pressure tower reflux tank 46 is refluxed to the negative pressure distillation tower 4, and a part is extracted as refined methanol and extracted to the refined methanol tank 18, and the gas phase in the negative pressure tower reflux tank 46 is condensed by the negative pressure tower top secondary condenser 66 for subsequent treatment; the material in the bottom of the negative pressure distillation tower 4 is preheated by the pressurized tower primary feed preheater 19 and the pressurized tower secondary feed preheater 20, and then enters the pressurized distillation tower 21;

[0050] The bottom of the pressurized distillation tower 21 is connected to the atmospheric distillation tower 15 through a pressurized tower kettle extraction pipeline 32, and a pressurized tower kettle pump 64 is provided on the pressurized tower kettle extraction pipeline 32. The pressurized tower kettle extraction pipeline 32 passes through the pressurized tower first-level feed preheater 19 to provide the heat required for heating the raw materials for the pressurized tower first-level feed preheater 19; the side line of the atmospheric distillation tower 15 extracts fusel alcohols, and the kettle of the atmospheric distillation tower 15 is provided with an atmospheric tower kettle extraction pipeline 30, which is used to extract wastewater, and the atmospheric tower kettle extraction pipeline 30 is provided with an atmospheric tower kettle pump 31.

[0051] Preferably, this embodiment makes full use of the heat of the top of the pre-distillation tower 2, the distillation tower 1, and the distillation tower 2; the heat of the kettle of the pre-distillation tower 2, the distillation tower 1, and the distillation tower 2; and the waste heat of the steam condensate. Specifically:

[0052] The top of the pre-distillation tower 2 is connected to the negative pressure tower reboiler 3 through the pre-tower top extraction pipeline 39, and the output end of the negative pressure tower reboiler 3 is connected to the pre-tower buffer tank 5 through the negative pressure tower reboiler output pipeline 40. The bottom of the pre-tower buffer tank 5 is provided with a pre-tower reflux pipeline 41, and the pre-tower reflux pipeline 41 is connected to the upper part of the pre-distillation tower 2. The pre-tower reflux pipeline 41 is provided with a pre-tower reflux pump 42. One side of the pre-tower buffer tank 5 is connected to an extraction water pipeline 43, and the upper part of the pre-tower buffer tank 5 is provided with a gas phase extraction pipeline 44. Pipeline 6; the gas phase at the top of the pre-distillation tower 2 exchanges heat with the negative pressure tower reboiler-3, and then enters the pre-tower buffer tank 5, into which extraction water is introduced, and the liquid phase refluxes to the pre-distillation tower 2 through the pre-tower reflux pipeline 41, and the gas phase is extracted through the gas phase extraction pipeline 6; the gas phase at the top of the pre-distillation tower 2 is used to heat the negative pressure tower reboiler-3, so as to make full use of the heat at the top of the pre-distillation tower 2, save the steam of the negative pressure distillation tower 4, and the top of the pre-distillation tower 2 does not need to be cooled by circulating water due to heat exchange, so a large amount of circulating water is saved;

[0053] The top of the pressurized distillation tower 21 is connected to the pre-tower reboiler 22 and the atmospheric tower reboiler 24 through a pressurized tower gas phase extraction pipeline 57. The output ends of the pre-tower reboiler 22 and the atmospheric tower reboiler 24 are both connected to the pressurized tower reflux tank 23. The bottom of the pressurized tower reflux tank 23 is provided with a pressurized tower reflux tank liquid phase extraction pipeline 58. The pressurized tower reflux tank liquid phase extraction pipeline 58 is provided with a pressurized tower reflux pump 59. The pressurized tower reflux tank liquid phase extraction pipeline 58 is respectively connected to a pressurized tower reflux pipeline 60 and a pressurized tower refined methanol extraction pipeline 61. Among them, the pressurized tower reflux pipeline 60 is connected to the middle and upper part of the pressurized distillation tower 21. The refined methanol extraction pipeline 61 of the pressurized distillation tower is connected to the refined methanol tank 18; the gas phase at the top of the pressurized distillation tower 21 supplies heat to the atmospheric pressure tower reboiler 24, and enters the pressurized tower reflux tank 23 after the heat supply, and the liquid phase in the pressurized tower reflux tank 23 partially refluxes to the pressurized distillation tower 21, and partially is extracted as refined methanol into the refined methanol tank 18; the gas phase at the top of the pressurized distillation tower 21 is used to supply heat to the atmospheric pressure tower reboiler 24, so as to make full use of the heat at the top of the pressurized distillation tower 21, save the steam at the top of the atmospheric pressure distillation tower 15, and the top of the pressurized distillation tower 21 does not need to be cooled by circulating water through heat exchange, thus saving a large amount of circulating water;

[0054] The top of the atmospheric distillation tower 15 is connected to the negative pressure tower reboiler 16 through the atmospheric pressure tower gas phase extraction pipeline 44, and the output end of the negative pressure tower reboiler 16 is connected to the atmospheric pressure tower reflux tank 17. The bottom of the atmospheric pressure tower reflux tank 17 is provided with an atmospheric pressure tower reflux tank liquid phase extraction pipeline 53, and the atmospheric pressure tower reflux tank liquid phase extraction pipeline 53 is provided with an atmospheric pressure tower reflux pump 54. The atmospheric pressure tower reflux tank liquid phase extraction pipeline 53 is respectively connected to the atmospheric pressure tower reflux pipeline 55 and the atmospheric pressure tower refined methanol extraction pipeline 56, wherein the atmospheric pressure tower reflux pipeline 55 is connected to the upper part of the atmospheric distillation tower 15, and the atmospheric pressure tower refined methanol extraction pipeline 56 is connected to the refined methanol The gas phase at the top of the atmospheric distillation tower 15 is heated by the pre-tower reboiler 22 and the negative pressure tower reboiler 16, and enters the atmospheric tower reflux tank 17 after heating. The liquid phase in the atmospheric tower reflux tank 17 is partially refluxed to the atmospheric distillation tower 15, and part is extracted as refined methanol to the refined methanol tank 18; the gas phase at the top of the atmospheric distillation tower 15 is used to heat the pre-tower reboiler 22 and the negative pressure tower reboiler 16, so as to make full use of the heat at the top of the atmospheric distillation tower 15, save the steam of the pre-distillation tower 2 and the negative pressure distillation tower 4, and the top of the atmospheric distillation tower 15 does not need to be cooled by circulating water through heat exchange, so a large amount of circulating water is saved;

[0055] The above-mentioned pressurized tower reboiler 25 is heated by steam, and the steam pipeline 62 passes through the pressurized tower reboiler 25, the pressurized tower secondary feed preheater 20, and the pre-tower feed preheater 1 in sequence. The output end of the pre-tower feed preheater 1 is connected with the condensate pipeline 63, that is, the pressurized tower secondary feed preheater 20 adopts the steam condensate of the pressurized tower reboiler 25 for preheating, and the pre-tower feed preheater 1 adopts the steam condensate of the pressurized tower secondary feed preheater 20 for preheating, thereby reducing the consumption of steam.

[0056] Embodiment three:

[0057] This embodiment provides a process for refining crude methanol with high water content, comprising the following steps:

[0058] After being preheated by the pre-tower feed preheater 1, the crude methanol enters the pre-distillation tower 2 for distillation; the gas phase at the top of the pre-distillation tower 2 goes to the negative pressure tower reboiler 3 to provide the heat required for distillation for the negative pressure distillation tower 4, and then enters the pre-tower buffer tank 5, the liquid phase in the pre-tower buffer tank 5 refluxes to the pre-distillation tower 2, and the gas phase in the pre-tower buffer tank 5 is extracted through the gas phase extraction pipeline 6;

[0059] The material in the bottom of the pre-distillation tower 2 enters the dehydration distillation tower 7. Before entering the dehydration distillation tower 7, the material in the bottom of the pre-distillation tower 2 is first preheated by the dehydration tower feed preheater 8. The gas phase at the top of the dehydration distillation tower 7 is pressurized and heated by the compressor 9 and then goes to the dehydration tower reboiler 10 to provide the heat required for distillation for the dehydration distillation tower 7. Then it goes to the pre-tower steam reboiler 11 to provide the heat required for distillation for the pre-distillation tower 2. Then, it is condensed by the dehydration tower top condenser 12 and enters the dehydration tower reflux tank 13. Part of the liquid phase in the dehydration tower reflux tank 13 is refluxed to the dehydration distillation tower 7, and part of it enters the negative pressure distillation tower 4; the material in the bottom of the dehydration distillation tower 7 is discharged as waste water after heat exchange with the dehydration tower feed preheater 8;

[0060] After condensation, part of the gas phase at the top of the negative pressure distillation tower 4 flows back to the negative pressure distillation tower 4, and part of it is extracted as refined methanol, which is collected into the refined methanol tank 18; the material in the bottom of the negative pressure distillation tower 4 is preheated by the atmospheric pressure tower feed preheater 14 and then enters the distillation tower 1;

[0061] Refined methanol is extracted from the top of the distillation tower 1, and the materials in the bottom of the distillation tower 1 enter the distillation tower 2; the distillation tower 1 in this embodiment adopts an atmospheric distillation tower 15, and the gas phase at the top of the atmospheric distillation tower 15 goes to the negative pressure tower reboiler 2 16 to provide the heat required for distillation for the negative pressure distillation tower 4, and then enters the atmospheric pressure tower reflux tank 17, and the liquid phase of the atmospheric pressure tower reflux tank 17 partially refluxes to the atmospheric distillation tower 15, and part of it is extracted as refined methanol, and the extracted refined methanol is extracted into the refined methanol tank 18; the materials in the bottom of the atmospheric distillation tower 15 are preheated in turn by the pressure tower first-level feed preheater 19 and the pressure tower second-level feed preheater 20 before entering the distillation tower 2;

[0062] Refined methanol is extracted from the top of the distillation tower 2, waste water is extracted from the bottom of the distillation tower 2, and fusel alcohol is extracted from one side of the distillation tower 2. The distillation tower 2 in this embodiment adopts a pressurized distillation tower 21, and a part of the gas phase at the top of the pressurized distillation tower 21 goes to the pre-tower reboiler 22 to provide the heat required for distillation for the pre-distillation tower 2, and then enters the pressurized tower reflux tank 23, and another part of the gas phase at the top of the pressurized distillation tower 21 goes to the atmospheric pressure tower reboiler 24 to provide the heat required for distillation for the atmospheric pressure distillation tower 15, and then enters the pressurized tower reflux tank 23; a part of the liquid phase in the pressurized tower reflux tank 23 is refluxed to the pressurized distillation tower 21, and a part is extracted as refined methanol, and the extracted refined methanol is extracted into the refined methanol tank 18; the material in the bottom of the pressurized distillation tower 21 goes to the pressurized tower primary feed preheater 19 to provide the heat required for heating the material for the pressurized tower primary feed preheater 19, and then is discharged as waste water.

[0063] In the present embodiment, the pressure tower reboiler 25 is heated by steam. The steam source can be ordinary boiler steam or steam generated in the reaction section. It can be selected according to the specific situation. No specific limitation is made in the present embodiment. The above-mentioned steam is sequentially provided with heat by the pressure tower reboiler 25, the pressure tower secondary feed preheater 20, the atmospheric pressure tower feed preheater 14, and the pre-tower feed preheater 1, and then extracted as condensate. That is, the pressure tower secondary feed preheater 20 uses the steam condensate of the pressure tower reboiler 25 for preheating, the atmospheric pressure tower feed preheater 14 uses the steam condensate of the pressure tower secondary feed preheater 20 for preheating, and the pre-tower feed preheater 1 uses the steam condensate of the atmospheric pressure tower feed preheater 14 for preheating, thereby reducing the consumption of steam.

[0064] Embodiment 4:

[0065] The difference between this embodiment and the third embodiment is that the first distillation tower in this embodiment adopts a pressure distillation tower 21, and the second distillation tower adopts an atmospheric distillation tower 15;

[0066] Specifically:

[0067] After being preheated by the pre-tower feed superheater 1, the crude methanol enters the pre-distillation tower 2 for distillation; the gas phase at the top of the pre-distillation tower 2 goes to the negative pressure tower reboiler 3 to provide the heat required for distillation for the negative pressure distillation tower 4, and then enters the pre-tower buffer tank 5, the liquid phase in the pre-tower buffer tank 5 refluxes to the pre-distillation tower 2, and the gas phase in the pre-tower buffer tank 5 is extracted through the gas phase extraction pipeline 6;

[0068] The material in the bottom of the pre-distillation tower 2 enters the dehydration distillation tower 7. Before entering the dehydration distillation tower 7, the material in the bottom of the pre-distillation tower 2 is first preheated by the dehydration tower feed preheater 8. The gas phase at the top of the dehydration distillation tower 7 is pressurized and heated by the compressor 9 and then goes to the dehydration tower reboiler 10 to provide the heat required for distillation for the dehydration distillation tower 7. Then it goes to the pre-tower steam reboiler 11 to provide the heat required for distillation for the pre-distillation tower 2. Then, it is condensed by the dehydration tower top condenser 12 and enters the dehydration tower reflux tank 13. Part of the liquid phase in the dehydration tower reflux tank 13 is refluxed to the dehydration distillation tower 7, and part of it enters the negative pressure distillation tower 4; the material in the bottom of the dehydration distillation tower 7 is discharged as waste water after heat exchange with the dehydration tower feed preheater 8;

[0069] After condensation, part of the gas phase at the top of the negative pressure distillation tower 4 flows back to the negative pressure distillation tower 4, and part of it is extracted as refined methanol, which is collected into the refined methanol tank 18; the materials in the bottom of the negative pressure distillation tower 4 are preheated in turn by the first-stage feed preheater 19 of the pressure tower and the second-stage feed preheater 20 of the pressure tower before entering the distillation tower 1;

[0070] Refined methanol is extracted from the top of the distillation tower one, and the materials in the bottom of the distillation tower one enter the distillation tower two; the distillation tower one in this embodiment adopts a pressure distillation tower 21, and the distillation tower two adopts an atmospheric distillation tower 15, a part of the gas phase at the top of the pressure distillation tower 21 goes to the pre-tower reboiler 22 to provide the heat required for distillation for the pre-distillation tower 2, and a part goes to the atmospheric pressure tower reboiler 24 to provide the heat required for distillation for the atmospheric pressure distillation tower 15, and then enters the pressure tower reflux tank 23, a part of the liquid phase of the pressure tower reflux tank 23 flows back to the pressure distillation tower 21, and a part is extracted as refined methanol, and the extracted refined methanol is extracted into the refined methanol tank 18; the materials in the bottom of the pressure distillation tower 21 go to the pressure tower first-level feed preheater 19 to provide the heat required for heating the materials for the pressure tower first-level feed preheater 19, and then enter the distillation tower two;

[0071] Refined methanol is extracted from the top of the distillation tower 2, waste water is extracted from the bottom of the distillation tower 2, and fusel alcohol is extracted from one side of the distillation tower 2. In this embodiment, the distillation tower 2 adopts an atmospheric distillation tower 15. The gas phase at the top of the atmospheric distillation tower 15 goes to the negative pressure tower reboiler 2 16 to provide the heat required for distillation for the negative pressure distillation tower 4, and then enters the atmospheric pressure tower reflux tank 17. A part of the liquid phase in the atmospheric pressure tower reflux tank 17 is refluxed to the atmospheric distillation tower 15, and a part is extracted as refined methanol. The extracted refined methanol is collected in the refined methanol tank 18;

[0072] In the present embodiment, the pressure tower reboiler 25 is heated by steam. The steam source can be ordinary boiler steam or steam generated in the reaction section. It can be selected according to the specific situation. No specific limitation is made in the present embodiment. The above-mentioned steam is sequentially provided with heat by the pressure tower reboiler 25, the pressure tower secondary feed preheater 20, and the pre-tower feed preheater 1, and then extracted as condensate. That is, the pressure tower secondary feed preheater 20 adopts the steam condensate of the pressure tower reboiler 25 for preheating, and the pre-tower feed preheater 1 adopts the steam condensate of the pressure tower secondary feed preheater 20 for preheating, thereby reducing the consumption of steam.

[0073] Embodiment five:

[0074] This embodiment provides a specific application scenario of Embodiment 1 and Embodiment 3: that is, the first distillation tower adopts an atmospheric distillation tower 15, and the second distillation tower adopts a pressurized distillation tower 21;

[0075] The crude methanol raw material contains: methanol: 65%, water: 35%-40%, ethanol: 300ppm; the raw material temperature is 40°C, the raw material pressure is 500KPaG, and the raw material flow rate is 20000KG / H;

[0076] After preheating, crude methanol enters the pre-distillation tower 2, the feed temperature of the pre-distillation tower 2 is 74°C, the feed pressure of the pre-distillation tower 2 is 500KPaG, the top temperature of the pre-distillation tower 2 is 70°C, the bottom temperature of the pre-distillation tower 2 is 81°C, the top pressure and bottom pressure of the pre-distillation tower 2 are 20°C and 23°C respectively, the reflux temperature of the pre-distillation tower 2 is 62°C, and the reflux flow rate of the pre-distillation tower 2 is 1843KG / H; the amount of the bottom of the pre-distillation tower 2 is 21444KPaG; the extraction water temperature of the pre-tower buffer tank 5 is 65°C, the extraction water pressure is 193KPaG, the extraction water flow rate is 1500KG / H, and the flow rate of the relaxation gas of the pre-tower buffer tank 5 is 31.4KG / H;

[0077] The material in the bottom of the pre-distillation tower 2 enters the dehydration distillation tower 7 after being preheated by the dehydration tower feed preheater 8. The feed temperature of the dehydration distillation tower 7 is 81°C, the feed pressure of the dehydration distillation tower 7 is 500KPaG, the top temperature and the bottom temperature of the dehydration distillation tower 7 are 62°C and 96°C respectively, the top pressure and the bottom pressure of the dehydration distillation tower 7 are -20KPaG and -15KPaG respectively, the flow rate of the top gas phase of the dehydration distillation tower 7 into the compressor 9 is 22600KG / H, the temperature of the top gas phase of the dehydration distillation tower 7 into the compressor 9 is 204°C, the pressure of the top gas phase of the dehydration distillation tower 7 into the compressor 9 is 230KPaG, the temperature (wastewater temperature) of the bottom of the dehydration distillation tower 7 after heat exchange with the dehydration tower feed preheater 8 is 95°C, and the output of the bottom of the dehydration distillation tower 7 is 7474KG / H;

[0078] The gas phase at the top of the dehydration distillation tower 7 is compressed and heated by the compressor 9, and then goes to the dehydration tower reboiler 10 to provide the heat required for distillation for the dehydration distillation tower 7. Then, after condensation, a part of it flows back to the dehydration distillation tower 7, and a part of it enters the negative pressure distillation tower 4. The feed temperature of the negative pressure distillation tower 4 is 62°C, the feed pressure of the negative pressure distillation tower 4 is 900KPaG, the feed flow rate of the negative pressure distillation tower 4 is 13970KG / H, the top temperature and the bottom temperature of the negative pressure distillation tower 4 are 52°C and 57°C respectively, the top pressure and the bottom pressure of the negative pressure distillation tower 4 are -45KPaG and -40KPaG respectively, the top output of the negative pressure distillation tower 4 is 6460KG / H, the reflux ratio of the negative pressure distillation tower 4 is 1:3, and the bottom output of the negative pressure distillation tower 4 is 7510KG / H;

[0079] The material in the bottom of the negative pressure distillation tower 4 is preheated by the atmospheric pressure tower feed preheater 14 and then enters the atmospheric pressure distillation tower 15. The feed temperature of the atmospheric pressure distillation tower 15 is 57°C, the feed pressure of the atmospheric pressure distillation tower 15 is 460KPaG, the feed flow rate of the atmospheric pressure distillation tower 15 is 7510KG / H, the top temperature and the bottom temperature of the atmospheric pressure distillation tower 15 are 72°C and 82°C respectively, the top pressure and the bottom pressure of the atmospheric pressure distillation tower 15 are 30KPaG and 50KPaG respectively, the top extraction of the atmospheric pressure distillation tower 15 is 2950KG / H, the reflux ratio of the atmospheric pressure distillation tower 15 is 2.3, and the bottom of the atmospheric pressure distillation tower 15 is 4560KG / H;

[0080] The material in the bottom of the atmospheric distillation tower 15 is preheated in turn by the first-stage feed preheater 19 of the pressure tower and the second-stage feed preheater 20 of the pressure tower, and then enters the pressure distillation tower 21. The feed temperature of the pressure distillation tower 21 is 132°C, the feed pressure of the pressure distillation tower 21 is 600KPaG, the feed flow rate of the pressure distillation tower 21 is 4560KG / H, the top temperature and the bottom temperature of the pressure distillation tower 21 are 120°C and 163°C respectively. The top pressure and bottom pressure of tower 21 are 550KPaG and 565KPaG respectively, the top extraction of pressure distillation tower 21 is 3010KG / H, the reflux ratio of pressure distillation tower 21 is 5, the bottom extraction of pressure distillation tower 21 is 950KG / H, the side extraction temperature of pressure distillation tower 21 is 134°C, the side extraction pressure of pressure distillation tower 21 is 563KPaG, and the side extraction flow rate of pressure distillation tower 21 is 600KG / H;

[0081] In this embodiment, the purity of the refined methanol extracted from the negative pressure distillation tower 4, the purity of the refined methanol extracted from the atmospheric distillation tower 15, and the purity of the refined methanol extracted from the pressurized distillation tower 21 can all reach 99.99%. The refined methanol extracted from the negative pressure distillation tower 4, the refined methanol extracted from the atmospheric distillation tower 15, and the refined methanol extracted from the pressurized distillation tower 21 meet the ethanol content of ≤50ppm after being combined; in this embodiment, the waste water extracted from the bottom of the pressurized distillation tower 21 and the waste water extracted from the bottom of the dehydration distillation tower 7 meet the methanol content of ≤10ppm after mixing, and can be directly discharged in compliance with the standards; the steam consumption in this embodiment is 0.69t steam / t refined alcohol.

[0082] In summary, due to the adoption of the above-mentioned technical scheme, in the present application, by setting up a dehydration distillation tower, it is possible to refine crude methanol with a high water content, and the energy at the top of the dehydration distillation tower is fully recycled and utilized through a compressor (heat pump) to provide heat to the dehydration tower reboiler to heat the distillate in the dehydration distillation tower kettle. The material after heat exchange with the dehydration tower reboiler is not directly extracted, nor does it directly enter the negative pressure distillation tower, but is processed by the dehydration tower reflux tank, and part of it is refluxed to the dehydration distillation tower, and part of it enters the negative pressure distillation tower, so as to further ensure the accuracy of subsequent distillation, and then ensure the accuracy of the final methanol product; more preferably, the material in the dehydration distillation tower kettle goes to the dehydration tower feed preheater, providing the dehydration tower feed preheater with the required heating material. Heat, further saving the consumption of external steam, and making full use of the heat of the dehydration distillation tower kettle material; the above-mentioned low-grade heat at the top of the dehydration distillation tower is converted into high-grade heat to meet the heat demand of the dehydration tower reboiler; for crude methanol with a water content of 35%, the methanol content can reach 91% after dehydration, and the purity of methanol after refining is 99.99%, the ethanol content in the refined methanol is ≤50ppm, and the methanol content in the wastewater is ≤10ppm, which can meet the discharge standards; it overcomes the problem of using a pre-tower to remove light, the kettle liquid directly enters the dehydration tower for distillation and dehydration, the energy consumption is extremely high, and the feed crude alcohol generally fluctuates. Through the improvement of the present application, the subsequent distillation accuracy problem can be guaranteed, and the technical transformation is convenient, the energy consumption is reduced, and the investment is reduced.

[0083] In addition, this application also has the following advantages:

[0084] 1. The steam at the top of the pre-distillation tower is used to heat the reboiler of the negative pressure tower, providing the heat required for distillation for the negative pressure distillation tower, making full use of the heat of the steam at the top of the pre-distillation tower, saving the steam of the negative pressure distillation tower and reducing the steam consumption of the system; the top of the pre-distillation tower does not need to be cooled by circulating water, saving a lot of circulating water;

[0085] 2. Make full use of the steam heat at the top of the distillation tower 1 and the distillation tower 2. When the distillation tower 1 and the distillation tower 2 respectively use an atmospheric distillation tower and a pressurized distillation tower, the steam at the top of the atmospheric distillation tower provides heat for the negative pressure tower reboiler 2, and then provides the heat required for distillation for the negative pressure distillation tower. The heat at the top of the atmospheric distillation tower is utilized, saving the steam of the negative pressure distillation tower; the steam at the top of the pressurized distillation tower provides heat for the pre-tower reboiler and the atmospheric tower reboiler, and then provides the heat required for distillation for the pre-distillation tower and the atmospheric distillation tower, saving the steam of the atmospheric distillation tower and the pre-distillation tower. Only the pressurized distillation tower uses steam in the whole process, and the tops of the pressurized distillation tower, the atmospheric distillation tower and the pre-distillation tower do not need to be cooled by circulating water, saving a large amount of circulating water;

[0086] When the first distillation tower and the second distillation tower adopt a pressurized distillation tower and an atmospheric distillation tower respectively, the steam at the top of the pressurized distillation tower provides heat for the pre-tower reboiler and the atmospheric distillation tower reboiler, and then provides the heat required for distillation for the pre-distillation tower and the atmospheric distillation tower, and the heat at the top of the pressurized distillation tower is utilized, saving the steam of the pre-distillation tower and the atmospheric distillation tower; the steam at the top of the atmospheric distillation tower provides heat for the second negative pressure tower reboiler, and then provides the heat required for distillation for the negative pressure distillation tower, and the heat at the top of the atmospheric distillation tower is utilized, saving the steam of the negative pressure distillation tower; only the pressurized distillation tower uses steam in the whole process, and the tops of the pressurized distillation tower, the atmospheric distillation tower and the pre-distillation tower do not need to be cooled by circulating water, saving a large amount of circulating water;

[0087] 3. Make full use of the waste heat of the system and the waste heat of the steam condensate. When the first and second distillation towers are atmospheric distillation towers and pressurized distillation towers respectively, the material in the kettle of the pressurized tower provides heat for the first-level feed preheater of the pressurized tower, and the steam is successively provided to the reboiler of the pressurized tower, the second-level feed preheater of the pressurized tower, the atmospheric tower feed preheater, and the pre-tower feed preheater, and then extracted as condensate; that is, the second-level feed preheater of the pressurized tower uses the steam condensate of the pressurized tower reboiler for preheating, the atmospheric tower feed preheater uses the steam condensate of the second-level feed preheater of the pressurized tower for preheating, and the pre-tower feed preheater uses the steam condensate of the atmospheric tower feed preheater for preheating, thereby reducing steam consumption;

[0088] When the first and second distillation towers are pressurized distillation towers and atmospheric distillation towers respectively, the materials in the kettle of the pressurized tower go to the first-level feed preheater of the pressurized tower to provide the heat required for heating the materials for the first-level feed preheater of the pressurized tower, and then enter the atmospheric pressure tower; the steam sequentially provides heat to the reboiler of the pressurized tower, the second-level feed preheater of the pressurized tower, and the feed preheater of the pre-tower, and then is extracted as condensate, that is, the second-level feed preheater of the pressurized tower is preheated with the steam condensate of the reboiler of the pressurized tower, and the feed preheater of the pre-tower is preheated with the steam condensate of the second-level feed preheater of the pressurized tower, thereby reducing the consumption of steam;

[0089] 4. This application makes full use of the heat at the top of each tower and the waste heat of the condensate and steam condensate in the tower bottom to ensure that the methanol product is greater than 99.99%, while the steam unit consumption is ≤0.7t steam / t refined alcohol, which greatly reduces the steam consumption of the system and realizes multi-level energy utilization and heat coupling;

[0090] 5. The water content and alcohol content in the refined methanol obtained by the present application can be freely regulated, and the wastewater can be discharged in compliance with the standards without the need for further treatment.

[0091] The devices, connection relationships, etc. not specifically described above all belong to the prior art and will not be described in detail in the present invention.

[0092] The preferred embodiments of the present application are described in detail above in conjunction with the accompanying drawings; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

[0093] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the various possible combinations of this application will not be described separately.

[0094] In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

Claims

1. A crude methanol refining device with high water content, characterized in that: The invention comprises a pre-distillation tower (2), a dehydration distillation tower (7), a negative pressure distillation tower (4), a first distillation tower, and a second distillation tower connected in sequence. The top of the dehydration distillation tower (7) is provided with a dehydration tower gas phase extraction pipeline (33), the dehydration tower gas phase extraction pipeline (33) is connected to a dehydration tower reboiler (10), a compressor (9) is provided on the dehydration tower gas phase extraction pipeline (33), and the output end of the dehydration tower reboiler (10) is connected to a dehydration tower reflux tank (10) via a dehydration tower reboiler output pipeline (34). 13), a dehydration tower top condenser (12) is arranged on the dehydration tower reboiler output pipeline (34), a dehydration tower reflux tank extraction pipeline (35) is arranged at the bottom of the dehydration tower reflux tank (13), the dehydration tower reflux tank extraction pipeline (35) is respectively connected to the dehydration tower reflux pipeline (37) and the negative pressure tower feed pipeline (38), the dehydration tower reflux pipeline (37) is connected to the upper part of the dehydration distillation tower (7), and the negative pressure tower feed pipeline (38) is connected to the negative pressure distillation tower (4).

2. A high water content crude methanol refining device according to claim 1, characterized in that: The dehydration tower reboiler output pipeline (34) passes through the pre-tower steam reboiler (11).

3. A high water content crude methanol refining device according to claim 1, characterized in that: The top of the pre-distillation tower (2) is connected to the negative pressure tower reboiler (3) via a pre-tower top extraction pipeline (39), the output end of the negative pressure tower reboiler (3) is connected to the pre-tower buffer tank (5) via a negative pressure tower reboiler output pipeline (40), the bottom of the pre-tower buffer tank (5) is connected to the upper part of the pre-distillation tower (2) via a pre-tower reflux pipeline (41), an extraction water pipeline (43) is provided on one side of the pre-tower buffer tank (5), and a gas phase extraction pipeline (6) is provided on the upper part of the pre-tower buffer tank (5).

4. A high water content crude methanol refining device according to claim 1, characterized in that: The bottom of the pre-distillation tower (2) is connected to the dehydration distillation tower (7) via a pre-tower kettle extraction pipeline (26), and the pre-tower kettle extraction pipeline (26) is provided with a pre-tower kettle pump (27) and a dehydration tower feed preheater (8). The kettle of the dehydration distillation tower (7) extracts wastewater via a dehydration tower kettle extraction pipeline (65), and the dehydration tower kettle extraction pipeline (65) passes through the dehydration tower feed preheater (8).

5. The high-water-content crude methanol refining device according to claim 1, characterized in that: The first and second distillation towers are respectively an atmospheric distillation tower (15) and a pressurized distillation tower (21). The top of the atmospheric distillation tower (15) is connected to the second negative pressure tower reboiler (16) via an atmospheric tower gas phase extraction pipeline (44). The output end of the second negative pressure tower reboiler (16) is connected to the atmospheric tower reflux tank (17). The bottom of the atmospheric tower reflux tank (17) is provided with an atmospheric tower reflux tank liquid phase extraction pipeline (53). The atmospheric tower reflux tank liquid phase extraction pipeline (53) is respectively connected to an atmospheric tower reflux pipeline (55) and an atmospheric tower refined methanol extraction pipeline (56). The atmospheric tower reflux pipeline (55) is connected to the upper portion of the atmospheric distillation tower (15). The top of the pressurized distillation tower (21) is connected to the pre-tower reboiler (22) and the atmospheric tower reboiler (24) respectively through the pressurized tower gas phase extraction pipeline (57), the output end of the pre-tower reboiler (22) and the output end of the atmospheric tower reboiler (24) are respectively connected to the pressurized tower reflux tank (23), and the bottom of the pressurized tower reflux tank (23) is provided with a pressurized tower reflux tank liquid phase extraction pipeline (58), and the pressurized tower reflux tank liquid phase extraction pipeline (58) is respectively connected to the pressurized tower reflux pipeline (60) and the pressurized tower refined methanol extraction pipeline (61), wherein the pressurized tower reflux pipeline (60) is connected to the upper part of the pressurized distillation tower (21).

6. A high-water-content crude methanol refining device according to claim 5, characterized in that: The bottom of the negative pressure distillation tower (4) is connected to the atmospheric pressure distillation tower (15) through a negative pressure tower bottom extraction pipeline (28), and the negative pressure tower bottom extraction pipeline (28) is provided with an atmospheric pressure tower feed preheater (14); the bottom of the atmospheric pressure distillation tower (15) is connected to the pressurized distillation tower (21) through an atmospheric pressure tower bottom extraction pipeline (30), and the atmospheric pressure tower bottom extraction pipeline (30) is provided with a pressurized tower primary feed preheater (19) and a pressurized tower secondary feed preheater (20); the bottom of the pressurized distillation tower (21) is provided with a pressurized tower bottom extraction pipeline (32), and the pressurized tower bottom extraction pipeline (32) extracts wastewater, and the pressurized tower bottom extraction pipeline (32) passes through the pressurized tower primary feed preheater (19).

7. A high-water-content crude methanol refining device according to claim 6, characterized in that: The steam pipeline (62) passes through the pressure tower reboiler (25), the pressure tower secondary feed preheater (20), the atmospheric tower feed preheater (14), and the pre-tower feed preheater (1) in sequence, and the output end of the pre-tower feed preheater (1) is connected to the condensate pipeline (63).

8. The high-water-content crude methanol refining device according to claim 1, characterized in that: The first distillation tower and the second distillation tower are respectively a pressurized distillation tower (21) and an atmospheric distillation tower (15). The top of the pressurized distillation tower (21) is respectively connected to a pre-tower reboiler (22) and an atmospheric tower reboiler (24) through a pressurized tower gas phase extraction pipeline (57). The output end of the pre-tower reboiler (22) and the output end of the atmospheric tower reboiler (24) are both connected to a pressurized tower reflux tank (23). A pressurized tower reflux tank liquid phase extraction pipeline (58) is provided at the bottom of the pressurized tower reflux tank (23). The pressurized tower reflux tank liquid phase extraction pipeline (58) is respectively connected to a pressurized tower reflux pipeline (60) and a pressurized tower refined methanol extraction pipeline (61). The pressure tower reflux pipeline (60) is connected to the upper part of the pressure distillation tower (21); the top of the atmospheric distillation tower (15) is connected to the negative pressure tower reboiler 2 (16) through the atmospheric tower gas phase extraction pipeline (44); the output ends of the negative pressure tower reboiler 2 (16) are respectively connected to the atmospheric tower reflux tank (17); the bottom of the atmospheric tower reflux tank (17) is provided with an atmospheric tower reflux tank liquid phase extraction pipeline (53); the atmospheric tower reflux tank liquid phase extraction pipeline (53) is respectively connected to the atmospheric tower reflux pipeline (55) and the atmospheric tower refined methanol extraction pipeline (56); the atmospheric tower reflux pipeline (55) is connected to the upper part of the atmospheric distillation tower (15).

9. A high-water-content crude methanol refining device according to claim 8, characterized in that: The bottom of the negative pressure distillation tower (4) is connected to the pressurized distillation tower (21) via a negative pressure tower bottom extraction pipeline (28), the negative pressure tower bottom extraction pipeline (28) is provided with a pressurized tower primary feed preheater (19) and a pressurized tower secondary feed preheater (20), the bottom of the pressurized distillation tower (21) is provided with a pressurized tower bottom extraction pipeline (32), the pressurized tower bottom extraction pipeline (32) is connected to the middle and upper part of the atmospheric distillation tower (15), and the pressurized tower bottom extraction pipeline (32) passes through the pressurized tower primary feed preheater (19).

10. A crude methanol refining device with high water content according to claim 9, characterized in that: The steam pipeline (62) passes through the pressure tower reboiler (25), the pressure tower secondary feed preheater (20), and the pre-tower feed preheater (1) in sequence, and the output end of the pre-tower feed preheater (1) is connected to the condensate pipeline (63).

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