Four-tower distillation and membrane separation integrated system and method for distilling ethanol by using system

Abstract

The invention discloses a four-tower distillation and membrane separation integrated system, which comprises a mash liquid pre-heater, a negative pressure mash tower, a normal pressure mash tower, a medium pressure rectification tower and a high pressure rectification tower, wherein the high pressure rectification tower is sequentially connected to an alcohol gas overheating device and a membraneseparation device through pipelines, the membrane separation device comprises a low vacuum membrane assembly and a high vacuum membrane assembly, and the low vacuum membrane assembly and the high vacuum membrane assembly are connected in series. The method for distilling ethanol by using the system comprises that A, gas is removed from fermented mature mash to form degassed mash; B, the alcohol vapor is separated from the waste mash liquid in the degassed mash; C, the alcohol vapor is condensed to form a crude alcohol, the crude alcohol is distilled by the medium pressure rectification tower,and the obtained material enters the high pressure rectification tower; and D, the alcohol vapor entering the high pressure rectification tower is partially overheated, and the obtained material sequentially enters the low vacuum membrane assembly and the high vacuum membrane assembly to separate the ethanol and the water. According to the present invention, with the system and the method, the phenomenon of alcohol volatilization in the distillation process can be avoided, the consumption of freezing water and steam can be reduced, and the system and the method are energy-saving and environmentally friendly.

Description

technical field [0001] 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 [0002] 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. [0003] 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 c...

AI Technical Summary

Problems solved by technology

[0003] 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

Images