Glycerol-Assisted Distillation for MEG and 1,2-BDO Separation
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Solution Overview
Problem
Current methods for separating monoethylene glycol (MEG) and 1,2-butanediol (1,2-BDO) from their mixture are inefficient due to similar boiling points and the formation of a homogeneous minimum boiling azeotrope, leading to high energy costs and product degradation during distillation.
Innovation Solution
A process involving a distillation column where glycerol is fed above the mixture of MEG and 1,2-BDO, operating at specific temperature and pressure ranges, breaks the azeotrope and allows for the separation of MEG and 1,2-BDO by altering their relative volatilities, with MEG and glycerol removed as a bottoms stream and 1,2-BDO as an overhead stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fractional distillation is used to separate MEG and 1,2-BDO, then separation is attempted, but the process becomes complicated and energy-consuming due to similar boiling points and azeotrope formation
Solution Approach 1:
Glycerol is introduced as an intermediary substance to alter the relative volatilities of MEG and 1,2-BDO. The glycerol feed changes the vapor-liquid equilibrium relationships, enabling effective separation without requiring complex multi-column distillation systems. This intermediary substance facilitates the breaking of the azeotrope and improves separation efficiency.
Solution Approach 2:
The process utilizes parameter changes by operating at specific temperature ranges (50-250°C) and pressure ranges (0.1-400 kPa) to optimize the separation. By controlling these parameters and introducing glycerol, the relative volatilities of the components are altered, enabling effective separation at lower energy inputs compared to conventional high-temperature distillation.
2Manufacturing precision
If repeated heating at raised temperatures is used for distillation purification, then glycol purification is achieved, but product decomposition occurs
Solution Approach 1:
The process operates at optimized temperature and pressure parameters that prevent thermal degradation while achieving effective separation. By controlling the distillation conditions and using glycerol as a volatility-modifying agent, high purity MEG is obtained without subjecting the product to excessive temperatures that would cause decomposition.
3Manufacturing precision
If azeotropic distillation with azeotrope-forming agents is used, then separation is facilitated, but additional process steps are required to remove the agents
Solution Approach 1:
Glycerol serves as the intermediary substance that modifies relative volatilities without forming problematic azeotropes that require additional removal steps. Unlike traditional azeotropic distillation agents, glycerol can be easily separated from MEG in the bottoms stream, simplifying the overall process flow and reducing equipment complexity.
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 achieves high recovery and purity of MEG with minimal energy consumption and prevents product degradation, enabling efficient separation of MEG from a mixture with 1,2-BDO.
Implementation Method 1
distillation column where glycerol is fed above the mixture of MEG and 1,2-BDO, operating at specific temperature and pressure ranges, breaks the azeotrope and allows for the separation of MEG and 1,2-BDO by altering their relative volatilities
Implementation Method 2
breaks the azeotrope and allows for the separation of MEG and 1,2-BDO by altering their relative volatilities
Data Source
AI summary
A process for the separation of monoethylene glycol (MEG) and 1,2-butanediol (1,2-BDO) from a first mixture including MEG and 1,2-BDO, the process including providing the first mixture of MEG and 1,2-BDO as a feed to a distillation column. The process also includes providing a feed comprising glycerol to the distillation column above the first mixture. The process also includes operating the distillation column at a temperature in the range of from 50 to 250° C. and a pressure in the range of from 0.1 to 400 kPa. The process also includes removing a stream comprising MEG and glycerol as a bottoms stream from the distillation column and removing a stream comprising 1,2-BDO above the point at which the feed comprising glycerol is provided to the distillation column.