Ethanol Distillation Using Membrane Separation
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Solution Overview
Problem
The conventional distillation and dehydration of ethanol from beer mash is energy-intensive and costly, with molecular sieves becoming saturated and requiring frequent replacement, and the process necessitates high equipment expenses due to the need for multiple separating stages and reflux in rectifying columns.
Innovation Solution
A distillation method that incorporates membrane separation processes, particularly dynamic crossflow membrane filtration, to purify the feed and distillate, reducing energy consumption and eliminating the need for phase changes and material contaminations, allowing for direct feeding into the second distillation column and subsequent final dehydration using membrane vapor permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If molecular sieves are used for final dehydration of ethanol, then high ethanol purity (99-99.8%) is achieved, but the molecular sieves quickly become saturated with water requiring frequent regeneration and replacement
Solution Approach 1:
The patent implements a dual molecular sieve system where one sieve is active for dehydration while the other is being regenerated. The saturated molecular sieve is discarded from service and sent for regeneration using a portion of the produced high-purity ethanol, while the regenerated sieve returns to service. This continuous cycle of discarding saturated sieves and recovering them through regeneration resolves the contradiction by maintaining continuous high-purity ethanol production while managing the finite service life of molecular sieves.
2Manufacturing precision
If conventional distillation and dehydration methods are used, then ethanol is concentrated and purified, but the process is energy-intensive with high operating costs
Solution Approach 1:
The patent changes the fundamental parameter of water removal from thermal evaporation to physical adsorption. Instead of using heat to evaporate water from the ethanol-water mixture in conventional distillation, the patent uses molecular sieves that adsorb water molecules at lower temperatures. This parameter change from thermal to adsorptive separation dramatically reduces energy consumption while achieving the same ethanol purification goal.
Solution Approach 2:
The patent replaces the mechanical/thermal distillation system with an adsorption-based separation system. Rather than relying on heat-driven phase changes and reflux systems, the invention uses molecular sieves to selectively adsorb water from the ethanol mixture. This substitution of the separation mechanism eliminates the need for high-energy thermal processes while maintaining effective ethanol purification.
3Manufacturing precision
If multiple separating stages and high reflux are used in rectifying columns, then high degree of purity (90-95% ethanol) is achieved, but equipment expenses and operating costs increase significantly
Solution Approach 1:
The patent extracts the water removal function from the complex multi-stage distillation process and concentrates it into a single adsorption step using molecular sieves. Instead of passing the ethanol-water mixture through multiple rectifying columns with high reflux ratios, the invention directly introduces the mixture to molecular sieves that selectively adsorb water. This extraction of the separation function into a single efficient step reduces equipment complexity while achieving equivalent or superior ethanol concentration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method significantly reduces energy consumption, extends membrane filtration cycles, and lowers operating costs by minimizing the need for evaporation and equipment replacement, achieving high ethanol purity with reduced capital expenditures.
Implementation Method 1
the feed and/or a distillate of the second distillation column is purified by a membrane separation process
Implementation Method 2
This last dehydration is carried out with molecular sieves, in which crystalline zeolites adsorb H2O molecules like a sponge
Data Source
AI summary
A method for distilling ethanol from a mash includes feeding a fluid to a first distillation column. The fluid and a distillate of the first distillation column are delivered to a second distillation column. The fed fluid and/or distillate of the second distillation column is/are purified in a first and/or last step of the method by a membrane separation process.