CN110404285A - Four-column distillation and membrane separation integrated system and method for distilling ethanol - Google Patents

Abstract

The invention discloses a four-tower distillation and membrane separation integrated system, including a mash preheater, a negative pressure mash tower, an atmospheric pressure mash tower, a medium-pressure finishing tower and a high-pressure finishing tower; device and a membrane separation device; the membrane separation device includes a low vacuum membrane module and a high vacuum membrane module connected in series. The method for the above-mentioned systematic distillation of ethanol comprises the following steps: A, degassing the fermented mash to form a degassed mash; B, separating the wine vapor from the waste mash in the degassed mash; C, forming crude alcohol after the wine vapor is condensed, Crude alcohol enters the high-pressure fine column after being distilled in the medium-pressure fine column; D. Part of the alcohol vapor entering the high-pressure fine column is heated and then sequentially enters the low-vacuum membrane module and the high-vacuum membrane module to separate ethanol and water. The invention avoids the phenomenon of alcohol running out in the distillation process, reduces the consumption of frozen water and steam, and is energy-saving and environment-friendly.

Description

Four-column distillation and membrane separation integrated system and method for distilling ethanol

technical field

The invention relates to the technical field of ethanol production, in particular to a four-tower distillation and membrane separation integrated system and a method for distilling ethanol.

Background technique

Patent No. 201810719237.3 discloses a double-coarse, double-finishing, four-tower, four-effect energy-saving distillation system for producing fuel ethanol and its use method, mainly including a negative pressure mash tower, a degassing section, an atmospheric pressure mash tower, a medium-pressure finishing tower, and a high-pressure finishing tower. The fuel ethanol vapor dehydrated by molecular sieves is extracted from the alcohol vapor at the top of the purifier tower to heat the negative pressure mash tower.

Dehydration through molecular sieves has the following problems: ①The feeding and desorption process of molecular sieves is carried out intermittently, resulting in fluctuating high and low pressure at the top of the combined tower. The dehydration of the vapor phase into the molecular sieves is not easy to achieve automatic control, and the distillation operation is unstable, and it is easy to run out of alcohol. ②The amount of light alcohol produced in the molecular sieve dehydration process is large, and the alcohol content in the light alcohol accounts for about 25% of the finished product, which leads to an increase in the amount of light alcohol that needs to be processed by the distillation system and increases steam consumption.

Contents of the invention

Aiming at the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a four-tower distillation and membrane separation integrated system and a method for distilling ethanol thereof.

To achieve the above object, the present invention adopts the following technical solutions:

The first aspect of the present invention provides a four-tower distillation and membrane separation integrated system, including a mash preheater, a negative pressure mash tower, an atmospheric pressure mash tower, a medium-pressure finishing tower, and a high-pressure finishing tower; Connect the wine gas superheater and the membrane separation device; the membrane separation device includes a series low vacuum membrane module and a high vacuum membrane module; the inlet end of the low vacuum membrane module is connected with the wine gas superheater pipeline, and the low vacuum membrane module The outlet port of the high vacuum membrane module is connected to the inlet port of the high vacuum membrane module; the outlet port of the high vacuum membrane module is connected to the reboiler of the atmospheric pressure beer tower; Connector Ⅰ, desorption condenser Ⅱ and anhydrous vacuum pump.

Preferably, the low-vacuum membrane module and the high-vacuum membrane module each include a plurality of shell-and-tube membrane structures connected in series, and each shell-and-tube membrane structure includes an outer shell and an inner tube inside the outer shell, and the inner tube includes a ceramic tube and the molecular sieve membrane covering the outer surface of the ceramic tube.

The space between the shell and the inner tube is the shell side, and the inner space of the inner tube is the tube side. Negative pressure is drawn on the tube side, and alcohol vapor is passed through the shell side. After the alcohol vapor passes through the low vacuum membrane module and the high vacuum membrane module, the finished product The moisture in the tank can reach less than 0.5%. Most of the moisture and a small amount of ethanol pass through the inner tube, enter the desorption condenser through the tube side, and then enter the distillation section for recovery.

The outlet end of the tube side of the low vacuum membrane module is connected to the desorption condenser I, and the outlet end of the tube side of the high vacuum membrane module is connected to the desorption condenser II. The shell-side outlet of the low-vacuum membrane module is connected to the shell-side inlet of the high-vacuum membrane module, and the shell-side outlet of the high-vacuum membrane module is connected to the atmospheric pressure beer column reboiler.

Preferably, the atmospheric beer column reboiler includes the atmospheric beer column reboiler I and the atmospheric beer column reboiler II which respectively form closed loops with the atmospheric beer column through pipelines; the outlet of the high vacuum membrane module The end is specifically connected with the atmospheric pressure mash column reboiler II.

Preferably, the mash preheater includes a series-connected mash primary preheater, mash secondary preheater and mash tertiary preheater, and the atmospheric pressure mash column reboiler II passes through a pipeline It is connected with the finished product cooler through the mash three-stage preheater.

Preferably, both the outlet of the desorption condenser I and the outlet of the desorption condenser II are connected to the crude wine tank through pipelines.

A second aspect of the present invention provides the above-mentioned method for systematically distilling ethanol, which is characterized in that it comprises the following steps:

A, ferment mature mash to remove gas to form degassed mash;

B. Separation of wine vapor and waste mash in the degassed mash;

C. The alcohol vapor is condensed to form crude alcohol, and the crude alcohol enters the high-pressure refining column after being distilled in the medium-pressure refining column;

D. The alcohol vapor entering the high-pressure refining tower is concentrated to the alcohol vapor with alcohol content above 95% (v/v) at the top of the tower, and a part of it enters the low-vacuum membrane module and the high-vacuum membrane module sequentially after being heated to separate ethanol and water, fuel The ethanol vapor enters the atmospheric beer tower reboiler II to heat the atmospheric beer tower; most of the water and a small amount of ethanol enter the desorption condenser I and desorption condenser II to condense and then enter the distillation section for recovery;

Among them, the vacuum degree of the low-vacuum membrane module is 9-11kpa absolute pressure, and ordinary circulating water is passed through the desorption condenser Ⅰ; the vacuum degree of the high-vacuum membrane module is 2-4kpa absolute pressure, and 1°C low-temperature refrigeration is passed through the desorption condenser Ⅱ water.

Preferably, in step A, the mature fermented mash is preheated and fed at the top of the degassing section of the negative pressure beer tower, and the degassed fermented beer enters the bottom of the degassing section, and part of the mash flows into the negative pressure beer tower through an artesian pipeline, The rest enter the top of the atmospheric pressure mash tower after being preheated.

Preferably, in step B, the degassed mash is heated by the rising steam at the bottom of the tower while the degassed mash descends in the negative pressure mash tower and the normal pressure mash tower, the wine vapor ascends to separate from the waste mash, and the distiller's grains are discharged at the bottom of the tower and sent to the distiller's grains processing system.

Preferably, in step C, the wine vapor at the top of the negative pressure beer tower and the atmospheric pressure beer tower enters the crude wine tank after being condensed, and the crude alcohol in the crude wine tank enters the lower part of the medium-pressure finishing tower after being preheated, and the medium-pressure finishing tower The wine vapor at the top of the tower is often refluxed after being condensed in the reboiler of the mash tower, and the alcohol at the bottom of the tower is preheated and then enters the high-pressure finishing tower.

Preferably, in step D, after entering the high-pressure refining column, part of the alcohol evaporates and carries out vapor-liquid mass transfer exchange with the tower top reflux liquid, and gradually concentrates, until the alcohol vapor at the top of the tower is 95% (v/v) or more. After heating, remove the film dehydration device, through which the ethanol and water are separated; all the rest go to the atmospheric pressure beer tower reboiler to heat the atmospheric pressure beer tower, and the waste water in the high pressure finishing tower tank preheats the crude alcohol and then goes to the sewage treatment system;

The fuel ethanol steam is condensed and then enters the mash three-stage preheater to preheat the fermented mash, and finally the fuel ethanol product is obtained after being cooled by the finished product cooler; the ordinary circulating water is 26°C-28°C.

Beneficial effects of the present invention:

(1) The wine vapor of the present invention enters the shell side of the membrane separation device, and the tube side desorbs. The process of separation and desorption is continuous and stable, the dehydration effect is good, and the equipment occupies less area, less investment, energy saving and environmental protection; membrane dehydration is Continuous process, stable working pressure, will not have any impact on distillation, avoiding the phenomenon of running wine.

(2) The membrane dehydration process of the present invention conforms to Dalton's law of partial pressure. The lower the moisture in the shell side alcohol vapor of the membrane separation device, the higher the vacuum requirement on the vacuum side of the tube side. The higher the vacuum, the lower the condensation temperature. According to this principle, in order to reduce the consumption of chilled water, the condensation of light wine vapor on the vacuum side of the membrane dehydration process is divided into two sections. The membrane separation device includes low vacuum membrane modules and high vacuum membrane modules connected in series. The low vacuum membrane The light alcohol vapor in the module is cooled by ordinary circulating water, and the light alcohol vapor in the high-vacuum membrane module is cooled by low-temperature frozen water. Through the improvement of this structure, compared with the traditional molecular sieve dehydration, the consumption of frozen water is reduced by 2/3 quantity.

(3) The traditional molecular sieve dehydration device has a large amount of light alcohol, and the alcohol content in the light wine accounts for about 25% of the finished product. Because the desorption and separation are carried out simultaneously in the membrane separation device, the light alcohol content is very low, and the alcohol content in the light wine accounts for about 25% of the finished product. 5‰ of the finished product, the amount of light alcohol that needs to be processed in the distillation section is greatly reduced, and the steam consumption is reduced;

Simultaneously in the present invention, alcohol steam is extracted from the vapor phase of the high-pressure finishing tower, and the fuel ethanol steam after membrane dehydration is used for heating the atmospheric pressure mash tower, and the alcohol steam is extracted from the vapor phase of the top of the medium-pressure finishing tower, and dehydrated by molecular sieves Compared with the traditional process of using the fuel ethanol vapor to heat the negative pressure beer tower, because the alcohol vapor utilizes one more effect, thereby reducing the steam consumption, the present invention is more energy-saving;

The steam consumption of the entire process for producing one ton of fuel ethanol is no more than 1.0 tons, which can reduce steam by more than 30% compared with the traditional process.

(4) The four-tower distillation and the membrane separation device are not independent, nor are they a simple combination. There is heat coupling between the two. Without the combination of the two, the energy-saving effect cannot be achieved. Specifically, ① from the four-tower distillation The high-pressure refining tower in the working section extracts alcohol in the vapor phase, and the alcohol vapor passes through the membrane module for dehydration and then returns to the distillation section to heat the atmospheric pressure beer tower, realizing the repeated use of heat; 1%, which reduces the load of alcohol recovery in the distillation section, thereby reducing steam consumption; ③ After the combination, the energy saving effect is more significant, compared with the traditional three-tower three-effect distillation process + molecular sieve dehydration device and "double crude double fine four tower four effect Compared with Distillation Production Fuel Ethanol Process Technology and Device", the steam saving is more than 20%.

(5) Using the advanced four-effect heat-coupled distillation process, only the high-pressure finishing column needs raw steam to provide heat through the reboiler, and the wine vapor in the high-pressure finishing column provides heat to the medium-pressure finishing column through the reboiler, and the medium-pressure finishing column The wine vapor and finished product anhydrous ethanol vapor respectively provide heat to the atmospheric pressure beer tower through the reboiler, and the wine vapor in the atmospheric pressure beer tower provides heat to the negative pressure beer tower through the reboiler, which truly realizes that one tower enters the steam, and the four towers Work, the heat has been fully utilized, reducing steam consumption.

Description of drawings

Fig. 1 is a flowchart of the present invention;

Fig. 2 is the sectional structure schematic diagram of shell-and-tube membrane structure of the present invention;

Among the figure: 101, first stage preheater for mash, 102, second stage preheater for mash, 103, third stage preheater for mash, 2, degassing section, 3, condenser group of degassing section, 4, Crude wine tank, 5. Distillation vacuum pump, 6. Negative pressure beer tower condenser group, 7. Finished product cooler, 8. Negative pressure beer tower, 9. Atmospheric pressure beer tower feed preheater, 10. Atmospheric pressure beer tower , 11. Negative pressure mash tower reboiler, 12. Distiller's grains processing system, 13. Crude alcohol preheater, 14. Medium pressure finishing tower, 15. Medium pressure finishing tower reboiler, 16. Atmospheric pressure mash tower reboiler Device Ⅰ, 17. Feed preheater for high-pressure fine column, 18. High-pressure fine column, 19. Fusel oil separator, 20. Sewage treatment system, 21. Reboiler for fine column, 22. Condensate tank, 23. Boiler Room, 24. Atmospheric pressure mash tower reboiler II, 25. Wine gas superheater, 26. Low vacuum membrane module, 27. High vacuum membrane module, 28. Desorption condenser I, 29. Desorption condenser II, 30, Anhydrous vacuum pump, 31, casing, 32, ceramic tube, 33, molecular sieve membrane, 34, shell side, 35, tube side.

Detailed ways

It should be pointed out that the following detailed description is exemplary and intended to provide further explanation to the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In order to enable those skilled in the art to understand the technical solution of the present application more clearly, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

Four-tower distillation and membrane separation integrated system includes mash preheater, degassing section 2, degassing section condenser group 3, crude wine tank 4, distillation vacuum pump 5, negative pressure mash tower condenser group 6 and product cooler 7 . The mash preheater forms a closed circuit with the degassing section 2 through pipelines. In order to obtain a better preheating effect and improve production efficiency, the mash preheater includes a primary mash preheater 101 , a secondary mash preheater 102 and a tertiary mash preheater 103 connected in series.

The outlet end of the mash three-stage preheater 103 is respectively connected with the finished product cooler 7 and the degassing section 2, and the outlet end of the degassing section 2 passes through the pipeline in turn through the mash primary preheater 101 and the degassing section condenser The group 3 is respectively connected with the crude wine tank 4 and the distillation vacuum pump 5, and the outlet end of the negative pressure mash tower 8 passes through the pipeline successively through the mash secondary preheater 102 and the negative pressure mash tower condenser group 6 respectively with the crude wine The tank 4 is connected to a distillation vacuum pump 5 .

It also includes a negative pressure beer tower 8, an atmospheric pressure beer tower feed preheater 9, an atmospheric pressure beer tower 10, a negative pressure beer tower reboiler 11, an atmospheric pressure beer tower reboiler and a distiller's grains treatment system 12, degassing The outlet end of section 2 is connected with negative pressure beer tower 8 through pipeline, and the outlet end of degassing section 2 is connected with atmospheric beer tower 10 after the feed preheater 9 of normal pressure beer tower through pipeline, and the outlet of normal pressure beer tower 10 The end passes through the pipeline and connects the crude wine tank 4 after passing through the negative pressure mash tower reboiler 11.

The negative pressure beer column reboiler 11 forms a closed circuit with the negative pressure beer column 8 through pipelines, and the outlet end of the negative pressure beer column 8 is connected with the distiller's grains treatment system 12 through pipelines.

The atmospheric beer column reboiler includes the atmospheric beer column reboiler I16 and the atmospheric beer column reboiler II24 which respectively form a closed circuit with the atmospheric beer column 10 through pipelines; the atmospheric beer column 10 passes through the pipeline Form a closed loop with the atmospheric pressure beer column reboiler I16 and atmospheric pressure beer column reboiler II24 respectively, the outlet end of the atmospheric pressure beer column 10 passes through the pipeline and the normal pressure beer column feed preheater 9 and then connects with the distiller's grains treatment system 12 connect.

It also includes a crude alcohol preheater 13, a medium-pressure finishing column 14, a medium-pressure finishing column reboiler 15, an atmospheric pressure beer column reboiler I 16, a high-pressure finishing column feed preheater 17, a high-pressure finishing column 18, miscellaneous Alcohol oil separator 19, sewage treatment system 20, rectifying column reboiler 21, condensed water tank 22 and boiler room 23.

The outlet end of the crude wine tank 4 passes through the crude alcohol preheater 13 through the pipeline and then connects to the medium-pressure finishing tower 14, and the medium-pressure finishing tower 14 is reboiled with the medium-pressure finishing tower reboiler 15 and the atmospheric pressure beer column respectively through the pipeline The device I16 forms a closed loop; the atmospheric beer column reboiler I16 is also connected to the high-pressure finishing column 18 through pipelines.

The outlet end of the medium-pressure fine column 14 is connected with the high-pressure fine column 18 after passing through the high-pressure fine column feed preheater 17 through the pipeline, and the high-pressure fine column 18 is respectively connected with the medium-pressure fine column reboiler 15 and the fine column reboiler through the pipeline. The boiler 21 forms a closed circuit; the outlet end of the finishing column reboiler 21 is connected to the boiler room 23 after passing through the condensed water tank 22 and the high-pressure finishing column feed preheater 17 sequentially through pipelines.

The outlet end of the high-pressure fine tower 18 is connected to the fusel oil separator 19 through a pipeline, and the outlet end of the high-pressure fine tower 18 is also connected to the sewage treatment system 20 through a crude alcohol preheater 13 through a pipeline.

The high-pressure fine column 18 is connected successively with the wine gas superheater 25 and the membrane separation device through the pipeline; the membrane separation device includes a low vacuum membrane module 26 and a high vacuum membrane module 27 connected in series; the inlet port of the low vacuum membrane module 26 Connect with wine gas superheater 25 pipeline, the outlet end of low vacuum membrane module 26 is connected with the inlet end of high vacuum membrane module 27; The outlet end of the membrane module 26 and the outlet end of the high vacuum membrane module 27 are also connected to the anhydrous vacuum pump 30 through the desorption condenser I28 and the desorption condenser II29 respectively. The atmospheric pressure mash column reboiler II 24 is connected to the finished product cooler 7 through a pipeline through a three-stage mash preheater 103 . Both the outlet of the desorption condenser I28 and the outlet of the desorption condenser II29 are connected with the crude wine tank 4 through pipelines.

The low-vacuum membrane module 26 and the high-vacuum membrane module 27 both include a plurality of shell-and-tube membrane structures connected in series, as shown in FIG. , the inner tube includes a ceramic tube 32 and a molecular sieve membrane 33 covering the outer surface of the ceramic tube 32 .

The space between the outer casing 31 and the inner tube is the shell side 34, and the inner space of the inner tube is the tube side 35. Negative pressure is pumped at the tube side 35, and alcohol vapor is passed through the shell side 34. The alcohol vapor passes through the low vacuum membrane module 26 and the high vacuum membrane module 26. After the vacuum membrane module 27, the moisture in the finished product can reach below 0.5%. Most of the moisture and a small amount of ethanol pass through the inner tube, enter the desorption condenser through the tube pass 35, and then enter the distillation section for recovery.

The method for above-mentioned system distillation ethanol, comprises the following steps:

A. The fermented mash is preheated by the mash preheater and then enters the degassing section 2. The carbon dioxide and some low-boiling impurities in the matured mash are separated from the fermented mash under the negative pressure of the degassing section 2, containing miscellaneous alcohol vapor Enter the mash primary preheater 101 and degassing section condenser group 3 to condense, and then the condensate enters the crude wine tank 4; after the degassed fermented mash enters the bottom of the degassing section 2, part of the mash (about 47%) Flow into the negative pressure beer tower 8 through the artesian pipeline, and all the other (about 53%) enter the normal pressure beer tower 10 after being preheated by the normal pressure beer tower feed preheater 9;

Among them: the degassed mash is heated by the steam rising from the bottom of the negative pressure mash tower 8 while the degassing section 2 is descending to the negative pressure mash tower 8, and the wine vapor is separated from the waste mash upward; the waste mash is in the negative pressure mash tower 8 is discharged from the bottom of the tower and sent to the distiller's grains treatment system 12 for processing; after the wine vapor in the negative pressure beer tower 8 rises, part of it enters the bottom of the degassing section 2, and the rest of the crude wine vapor reaches the condenser of the negative pressure beer tower after passing through the beer preheater Group 6 is condensed, and the condensate enters the crude wine tank 4; the uncondensed miscellaneous gas is discharged through the distillation vacuum pump 5.

The mash preheater includes a mash primary preheater 101, a mash secondary preheater 102 and a mash tertiary preheater 103 which are sequentially connected by pipelines. The fermented mash passes through the mash primary preheater 101 is preheated to 45°C, mash secondary preheater 102 is preheated to 55°C, mash tertiary preheater 103 is preheated to about 61°C and then enters degassing section 2, the carbon dioxide in the mature mash and part of the low boiling point The impurities are separated from the fermented mash under the negative pressure of the degassing section 2, and the crude wine vapor containing impurities enters the primary preheater 101 of the mash; the crude wine vapor enters the secondary preheater 102 and the negative pressure mash tower condenser group 6 Condensation, condensate enters thick wine tank 4.

B, the part degassed mash that enters the atmospheric pressure beer tower 10 is heated by the steam rising at the bottom of the atmospheric pressure beer tower 10 while descending in the atmospheric pressure beer tower 10, and the wine vapor ascends and is separated from the waste mash; The bottom of the pressure beer tower 10 is discharged, and after the fermented beer is preheated, it is sent to the distiller's grains treatment system 12 for processing; the wine vapor in the atmospheric pressure beer tower 10 goes up into the negative pressure beer tower reboiler 11 to heat the negative pressure beer tower 8, and the condensed The crude alcohol enters the crude wine tank 4; the steam at the top of the normal pressure beer tower 10 passes through the negative pressure beer tower reboiler 11 to heat the negative pressure beer tower 8. The operating temperature at the bottom of the negative pressure beer tower 8 is 80°C, the temperature at the top is 65°C, and the temperature at the top of the degassing section 2 is 60°C.

C, the crude alcohol from the crude wine tank 4 enters the medium pressure finishing tower 14 after being preheated by the crude alcohol preheater 13 (exchanging heat with the waste water at the bottom of the high-pressure finishing tower 18), and after entering the tower, part of the alcohol is evaporated with The reflux liquid at the top of the tower undergoes vapor-liquid mass transfer and exchange, and gradually concentrates until the alcohol vapor at the top of the tower is more than 95% (v/v) and enters the atmospheric pressure beer column reboiler I16 to heat the atmospheric pressure beer column 10, and the condensed part reflux, and the rest enter the top of the high-pressure finishing column 18.

The medium-pressure finishing column 14 works under positive pressure, and its working pressure is 0.25MPa. The heating method of the medium-pressure finishing column 14 is: the alcohol vapor at the top of the high-pressure finishing column 18 passes through the medium-pressure finishing column reboiler 15 to heat the medium-pressure finishing column. Tower 14. The operating temperature at the bottom of the medium-pressure finishing column 14 is 121°C, and the temperature at the top is 113°C.

D, the light wine from the bottom of the medium-pressure finishing tower 14 enters the middle part of the high-pressure finishing tower 18 after being preheated by the high-pressure finishing tower feed preheater 17 (with steam condensate water), and the alcohol is gradually concentrated after entering the tower. The alcohol concentration at the top of the tower can reach more than 95% (v/v), and the intermediate impurities (fusel oils) stay in the upper layers of the feed plate, and enter the fusel oil separator 19 to separate the fusel alcohol after extraction and cooling Oil. The alcohol vapor extracted from the vapor phase at the top of the high-pressure fine column 18 is 95% (v/v) or more and enters the membrane separation device for dehydration through the alcohol gas superheater 25, and the rest of the alcohol vapor is condensed through the medium-pressure fine column reboiler 15 Reflow all. The waste hot water in the high-pressure finishing tower 18 is preheated to the sewage treatment system 20 after the crude alcohol is preheated.

The high-pressure fine column 18 works under positive pressure, and its working pressure is 0.45MPa. The heating method of the high-pressure fine column 18: the fresh steam from the boiler room passes through the high-pressure fine column 18 reboiler 21 to heat the high-pressure fine column 18. The operating temperature at the bottom of the high-pressure finishing column 18 is 155°C, and the temperature at the top is 126°C.

The alcohol vapor entering the membrane separation device first enters the low-vacuum membrane module 26. The vacuum degree of the low-vacuum membrane module 26 is 9-11kpa absolute pressure, and only ordinary circulating water (28°C) is condensed through the desorption condenser Ⅰ28. The module 26 can remove more than 65% of the moisture in the raw alcohol; the alcohol vapor dehydrated by the low vacuum membrane module 26 enters the high vacuum membrane module 27. The low-temperature frozen water at ℃ is condensed through the desorption condenser II 29, and the high-vacuum membrane module 27 can only remove 35% of the moisture in the raw alcohol. The device separates ethanol and water, and finally obtains fuel ethanol. Condensation in two-stage condensers saves the demand for chilled water.

The dehydrated fuel ethanol steam enters the atmospheric beer tower reboiler II 24 to heat the atmospheric beer tower 10, and after condensation, enters the three-stage preheater 103 for preheating the fermented beer, and finally cools it in the finished product cooler 7 to obtain fuel ethanol finished product.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (10)

1. A four-tower distillation and membrane separation integrated system, including a mash preheater, a negative pressure mash tower (8), an atmospheric pressure mash tower (10), a medium-pressure finishing tower (14) and a high-pressure finishing tower (18); It is characterized in that: the high-pressure fine column (18) is sequentially connected to the wine gas superheater (25) and the membrane separation device through pipelines; the membrane separation device includes a low-vacuum membrane module (26) and a high-vacuum membrane module (27) connected in series; The inlet end of the low vacuum membrane module (26) is connected with the wine gas superheater (25) pipeline, and the outlet end of the low vacuum membrane module (26) is connected with the inlet end of the high vacuum membrane module (27); The outlet port of the module (27) is connected with the reboiler of the normal pressure beer column; the outlet port of the low vacuum membrane module (26) and the outlet port of the high vacuum membrane module (27) also pass through the desorption condenser I (28), the desorption Condenser II (29) is connected with anhydrous vacuum pump (30). 2. The system according to claim 1, characterized in that: the low-vacuum membrane module (26) and the high-vacuum membrane module (27) each comprise a plurality of shell-and-tube membrane structures connected in series, each shell-and-tube membrane The structures all include an outer shell (31) and an inner tube inside the outer shell (31), and the inner tube includes a ceramic tube (32) and a molecular sieve membrane (33) covered on the outer surface of the ceramic tube (32). 3. system according to claim 1, is characterized in that: described atmospheric beer tower reboiler comprises the atmospheric beer tower reboiler I ( 16) and the atmospheric pressure beer column reboiler II (24); the outlet end of the high vacuum membrane module (27) is specifically connected to the atmospheric pressure beer column reboiler II (24). 4. The system according to claim 3, characterized in that: the mash preheater comprises a mash primary preheater (101), a mash secondary preheater (102) and a mash tertiary preheater. Heater (103), the atmospheric pressure beer column reboiler II (24) is connected with the product cooler (7) through the three-stage preheater (103) of the beer liquid through the pipeline. 5. The system according to claim 1, characterized in that: the outlet of the desorption condenser I (28) and the outlet of the desorption condenser II (29) are both connected to the crude wine tank (4) through pipelines. 6. utilize the method for the system distillation ethanol described in any one of claim 1-5, it is characterized in that, comprise the following steps: A, ferment mature mash to remove gas to form degassed mash; B. Separation of wine vapor and waste mash in the degassed mash; C, wine vapor forms crude ethanol after condensation, and crude alcohol enters high-pressure finishing tower (18) after medium-pressure finishing tower (14) distillation; D, the alcohol vapor entering the high-pressure finishing tower (18) is concentrated to the alcohol vapor above the tower top alcohol content of 95% (v/v), and a part enters the low-vacuum membrane module (26) and the high-vacuum membrane module (26) sequentially after heating 27) Separate ethanol from water, fuel ethanol steam enters the atmospheric pressure beer column reboiler II (24) to heat the atmospheric pressure beer column (10); most of the water and a small amount of ethanol enter the desorption condenser I (28) and desorption Condenser II (29) enters the distillation section for recovery after condensation; Among them, the vacuum degree of the low vacuum membrane module (26) is absolute pressure 9kpa-11kpa, and ordinary circulating water is passed through the desorption condenser I (28); Low-temperature chilled water of 1° C. is passed through the device II (29). 7. The method according to claim 6, characterized in that, in step A, the fermented fermented mash is fed at the top of the negative pressure mash tower (8) degassing section (2) after preheating, and the fermented mash degassed After entering the bottom of the degassing section (2), part of the mash flows into the negative pressure mash tower (8) through an artesian pipeline, and the rest enters the top of the normal pressure mash tower (10) after being preheated. 8. method according to claim 6 is characterized in that, in step B, degassing mash is heated by the steam rising at the bottom of the tower while descending in negative pressure mash tower (8) and normal pressure mash tower (10), The wine vapor ascends and is separated from the waste mash, and the distiller's grains are discharged at the bottom of the tower and sent to the distiller's grains treatment system (12). 9. method according to claim 6 is characterized in that, in step C, the wine vapor of negative pressure beer tower (8) and atmospheric pressure beer tower (10) tower top enters crude wine tank (4) after condensation, The crude alcohol in the crude wine tank (4) enters the lower part of the medium-pressure finishing column (14) after being preheated, and the wine vapor at the top of the medium-pressure finishing column (14) is usually refluxed after being condensed by the reboiler of the mash column, and the alcohol at the bottom of the column is condensed. After preheating, it enters the high-pressure finishing column (18). 10. The method according to claim 6, characterized in that, in step D, after entering the high-pressure finishing tower (18), part of the alcohol evaporates and carries out vapor-liquid mass transfer exchange with the tower top reflux liquid, gradually concentrates, until the tower top wine Alcohol vapor part that is more than 95% (v/v) passes through heat and removes membrane dehydration device, ethanol and water are separated by this device; All the other go to normal pressure beer tower reboiler to heat atmospheric pressure beer tower (10), After preheating the crude alcohol, the waste hot water in the high pressure finishing tower (18) goes to the sewage treatment system (20); After the fuel ethanol steam is condensed, it enters the mash three-stage preheater (103) to preheat the fermented mash, and finally the fuel ethanol product is obtained after being cooled by the finished product cooler (7); the ordinary circulating water is 26°C-28°C.