Ethanol Purification via Base Reaction and Adsorption
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Solution Overview
Problem
Conventional distillation methods are inadequate for achieving high purity ethanol from fermentation broths containing microbial biomass, ethanol, methanol, ethyl acetate, and other by-products, as they fail to effectively separate these components due to similar boiling points and the formation of azeotropes.
Innovation Solution
A method involving multiple separation steps, including separating microbial biomass, reacting ethyl acetate with a base followed by distillation, adsorbing thiols, and conducting distillations in inert atmospheres, to generate a high-purity ethanol product, utilizing distillation in single or multiple columns and employing adsorbents like strongly acidic cation exchange resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation is used to separate ethanol from fermentation broth, then the separation process is simple, but the purity of ethanol cannot be achieved at high enough levels due to similar boiling points and azeotrope formation
Solution Approach 1:
The separation process is divided into multiple sequential stages: first removing microbial biomass through filtration or centrifugation, then conducting multiple distillation passes with intermediate treatments. Each stage targets specific impurities, progressively increasing ethanol purity beyond what a single distillation could achieve.
Solution Approach 2:
Adsorbent materials are introduced as intermediary substances to selectively bind and remove specific impurities like thiols and heavy metals from the fermentation broth before distillation. These adsorbents act as mediators that facilitate separation of components with similar boiling points by removing interfering substances first.
2Manufacturing precision
If multiple separation steps are implemented to achieve high purity ethanol, then ethanol purity is improved, but the process complexity and number of operation steps increase
Solution Approach 1:
Microbial biomass is removed through filtration or centrifugation before distillation begins. Adsorbents are added to the fermentation broth in advance to pre-remove interfering impurities. These preliminary actions simplify subsequent distillation operations by eliminating substances that would otherwise complicate the separation process.
Solution Approach 2:
Multiple separation functions are combined into integrated process units. For example, adsorption vessels are positioned in-line with distillation columns, and filtration systems are integrated with the broth handling infrastructure. This merging reduces the number of discrete manual operations while maintaining multiple separation stages.
3Manufacturing precision
If multiple distillation columns are used to separate different by-products, then separation effectiveness is improved, but equipment complexity and investment cost increase
Solution Approach 1:
Different sections of the distillation system are optimized for specific separation tasks. Certain columns or column sections are designed with specific packing materials, tray configurations, or temperature profiles tailored to separate particular by-products like methanol, ethyl acetate, or thiols. This localized optimization achieves effective multi-component separation without requiring completely separate systems for each impurity.
Solution Approach 2:
The separation process utilizes multiple dimensions beyond just the number of columns: temperature gradients, pressure variations, and compositional differences are exploited as additional separation dimensions. Intermediate treatment steps like chemical reactions or phase changes are introduced to create new separation dimensions that reduce reliance on adding more distillation columns.
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 effectively removes impurities and by-products, achieving high purity ethanol by optimizing the order of separation steps and using appropriate adsorbents, thereby meeting the requirements for high-purity ethanol production.
Implementation Method 1
removing ethyl acetate by reacting ethyl acetate with a base compound followed by distillation
Implementation Method 2
removing at least one thiol by adsorption or reaction to disulphide
Implementation Method 3
The distillation process is based on the difference in the volatility, i.e., the difference in boiling point, of the components to be separated
Implementation Method 4
removing the acetaldehyde, after removal of the microbial biomass to generate a process stream, by using a metal to reduce the acetaldehyde to an acetate followed by distillation
Data Source
AI summary
The disclosure is directed to an apparatus and method for recovering ethanol from a fermentation broth. The fermentation broth comprises microbial biomass, ethanol, methanol, ethyl acetate, at least one thiol, and at least one compound having 3 or more carbon atoms. The method comprises separating at least microbial biomass from the fermentation broth to generate a process stream; removing, in any order, from the process stream: ethyl acetate by reacting ethyl acetate with a base compound followed by distillation; at least one thiol by adsorption or reaction to disulfide; methanol by distillation; compounds having 3 or more carbon atoms by distillation; and recovering ethanol by distillation; wherein the distillations may be conducted in a single column or two or more columns.