Zeolite Membrane Treatment for Absolute Alcohol Purity
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Solution Overview
Problem
Existing methods for producing absolute alcohol, such as azeotropic distillation and membrane separation, often result in products containing trace amounts of ethyl acetate or benzene, which are not safe for use in external preparations or cosmetics, and can have off-odors due to acetal formation from acetaldehyde in the raw materials.
Innovation Solution
A method involving zeolite membrane treatment of crude alcohol with an alcohol concentration of at least 95 v/v%, reducing acetaldehyde and total organic impurities to produce absolute alcohol with acetal content below 0.4 mg/L, ensuring the product is free from off-odors and suitable for use in cosmetics and external preparations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If azeotropic distillation is used to produce absolute alcohol, then ethanol concentration reaches 99.5 v/v% or more, but trace amounts of ethyl acetate or benzene mix into the product causing safety issues and off-odors
Solution Approach 1:
The patent extracts and removes harmful impurities (ethyl acetate, benzene, acetaldehyde) from the ethanol stream using selective adsorption materials. The adsorption step specifically targets and removes these harmful substances while preserving the ethanol, achieving high purity without the contamination problems of azeotropic distillation.
Solution Approach 2:
The patent introduces an intermediary adsorption step between distillation and final product formation. This intermediary stage uses selective adsorbents to capture harmful impurities, acting as a mediator that prevents contamination while maintaining high ethanol concentration.
2Productivity
If membrane separation is used to produce absolute alcohol, then separation efficiency improves, but acetaldehyde in raw materials converts to acetal causing off-odors
Solution Approach 1:
The patent applies preliminary action by removing acetaldehyde from the raw material before the membrane separation step. By pre-removing the precursor substance (acetaldehyde) through selective adsorption, the subsequent membrane separation process does not generate harmful acetals, eliminating the off-odor problem while maintaining high productivity.
Solution Approach 2:
The patent applies preliminary anti-action by preventing acetal formation before it can occur. The selective adsorption step preemptively removes acetaldehyde, counteracting the potential harmful conversion to acetal that would otherwise occur during membrane separation or storage.
3Manufacturing precision
If multiple distillation columns are used to separate impurities, then purification effectiveness increases, but process complexity and equipment investment increase
Solution Approach 1:
The patent replaces the mechanical distillation system with a chemical adsorption system. Instead of using multiple distillation columns based on boiling point differences, the invention uses selective adsorption materials that chemically target and remove specific impurities, simplifying the equipment while maintaining or improving purification effectiveness.
Solution Approach 2:
The patent changes the separation mechanism from physical (distillation based on volatility) to chemical (adsorption based on molecular recognition). This parameter change allows for more selective and efficient impurity removal with simpler equipment, as adsorption can target specific molecules regardless of their boiling points.
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
The method effectively produces a high-quality, safe absolute alcohol free from off-odors, suitable for direct human contact applications, by controlling acetaldehyde and organic impurity levels during zeolite membrane treatment.
Implementation Method 1
subjecting a raw material alcohol to a zeolite membrane treatment
Implementation Method 2
zeolite membrane treatment of crude alcohol with an alcohol concentration of at least 95 v/v%
Implementation Method 3
reducing acetaldehyde and total organic impurities to produce absolute alcohol with acetal content below 0.4 mg/L
Data Source
AI summary
A method for producing an absolute alcohol containing not more than 0.4 mg/L of acetal by subjecting a raw material alcohol to a zeolite membrane treatment, the raw material alcohol being obtained by distilling a crude alcohol, and having an alcohol concentration of not less than 95 v/v%, and the raw material alcohol containing not more than 5 mg/L of acetaldehyde and not more than 60 mg/L of a total amount of organic impurities. An absolute alcohol can be produced, which absolute alcohol is highly safe to the human body and has a quality that no off-odor is felt by human senses. In addition, the contents of diacetyl and crotonaldehyde in the raw material alcohol may be set at levels not more than particular values, respectively.