Glycol Separation Using Extractive Distillation
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Solution Overview
Problem
Current methods for separating glycols, such as ethylene glycol and propylene glycol, from mixtures containing close-boiling and azeotrope-forming components are energy-intensive, require complex equipment, and often result in contaminated products due to high temperatures and multiple separation steps.
Innovation Solution
A process involving a series of distillation columns with specific temperature and pressure ranges, using an extractant like glycerol to facilitate the separation of high purity diols from a product stream derived from saccharide hydrogenolysis, without forming azeotropes and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fractional distillation is used to separate glycols, then separation of glycols can be achieved, but energy consumption increases and product decomposition occurs due to high temperatures
Solution Approach 1:
The patent changes the operating parameters of distillation by using lower temperatures and optimized pressure conditions. The process operates at temperatures below the decomposition point of glycols while maintaining effective separation through controlled reflux ratios and staged distillation, thereby reducing energy consumption and preventing product degradation.
Solution Approach 2:
The patent divides the separation process into multiple stages using a series of distillation columns rather than a single high-temperature column. Each column performs a specific separation function at optimized temperature and pressure conditions, allowing progressive purification without subjecting the product to excessive heat that would increase energy consumption and cause decomposition.
2Manufacturing precision
If multiple distillation steps are used to achieve high purity glycol separation, then product purity improves, but process complexity and equipment requirements increase
Solution Approach 1:
The patent combines multiple separation functions into an integrated multi-column distillation system where columns are thermally coupled. The reboiler of one column serves as the condenser for another, and intermediate streams are exchanged between columns. This merging of heat transfer and separation functions achieves high purity separation while reducing the total number of independent equipment units and simplifying overall process complexity.
3Manufacturing precision
If conventional distillation is used for glycol separation, then separation can be achieved, but operational costs and capital expenditure increase
Solution Approach 1:
The patent implements a self-service distillation system where the process generates its own heating requirements through internal heat integration. The hot product streams from earlier separation stages automatically provide the heating duty for subsequent columns, and condensates from later stages supply cooling requirements. This self-sufficient heat management eliminates the need for external utility systems, reducing both capital expenditure on utility infrastructure and operational costs for steam and cooling water.
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 process achieves high purity diol separation with reduced energy requirements and simpler equipment, avoiding the formation of azeotropes and minimizing product contamination, thereby improving operational efficiency and product quality.
Implementation Method 1
A process involving a series of distillation columns with specific temperature and pressure ranges, using an extractant like glycerol to facilitate the separation of high purity diols from a product stream
Implementation Method 2
using an extractant like glycerol to facilitate the separation of high purity diols from a product stream derived from saccharide hydrogenolysis, without forming azeotropes
Data Source
AI summary
A process for the production of a high purity first diol from a product stream comprising two or more C2 to C7 diols, said process comprising the steps of: (i) providing the product stream to a first distillation column; (ii) providing an extractant selected from the group of C3 to C6 sugar alcohols and mixtures thereof to the first distillation column; (iii) operating the first distillation column to obtain a first bottoms stream comprising at least a first diol and the extractant; (iv) providing the first bottoms stream to a second distillation column operating to obtain a second top stream comprising the first diol and diols with atmospheric boiling points at least 10° C. higher than the first diol, and (v) providing the second top stream to a third distillation column to obtain a third top stream comprising the first diol; wherein the product stream comprises 0.1 to 10 wt % of diols with atmospheric boiling points at least 10° C. higher than the first diol, calculated upon the total weight of C2 to C7 diols in the product stream.