HMDA Purification Through Alcohol Extraction and Vacuum Distillation
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Solution Overview
Problem
Current methods for recycling hexamethylene diamine (HMDA) from aqueous solutions are energy-inefficient, leading to high economic costs and a significant carbon footprint.
Innovation Solution
A method involving the extraction of HMDA from an aqueous solution using a monovalent alcohol with 4 to 8 carbon atoms, followed by distillation at a pressure of 100-600 mbar, utilizing a single distillation column and a mixer-settler with 3 to 15 theoretical stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional distillation methods are used to separate HMDA from aqueous solutions, then separation is achieved, but energy consumption is high
Solution Approach 1:
The patent introduces an organic solvent as an intermediary substance to facilitate the separation of HMDA from aqueous solutions. The solvent acts as a mediator that selectively extracts HMDA from the aqueous phase, enabling separation at lower temperatures and reducing the energy demand of subsequent distillation steps while maintaining effective separation.
Solution Approach 2:
The patent optimizes key process parameters including distillation pressure (reducing to vacuum range), temperature profiles, and solvent-to-aqueous-phase ratios to minimize energy consumption. By carefully controlling these parameters, the process achieves efficient HMDA separation with significantly reduced thermal energy input compared to conventional atmospheric distillation.
2Reliability
If multiple distillation columns are used to concentrate HMDA or isolate it from the extract, then separation purity is improved, but device complexity and capital costs increase
Solution Approach 1:
The patent combines multiple separation functions into a single integrated distillation column design. The column is configured with specific theoretical stages and internal structures that simultaneously achieve concentration and purification of HMDA, eliminating the need for multiple separate distillation columns while maintaining high separation purity.
Solution Approach 2:
The single distillation column is designed to perform multiple functions: initial concentration of HMDA from the extract, further purification, and product recovery. This multi-functional design replaces what would traditionally require multiple specialized columns, reducing capital investment and operational complexity while achieving the same separation purity.
3Quantity of substance
If conventional extraction solvents are used, then HMDA extraction is achieved, but subsequent separation of the extractant requires additional distillation steps increasing energy consumption
Solution Approach 1:
The patent employs an extraction solvent system where the extractant can be easily recovered and reused. The selected solvent has properties that allow for low-energy recovery through simple distillation or phase separation, enabling the extractant to be discarded from the HMDA product stream and then recovered for repeated use in subsequent extraction cycles, minimizing overall energy consumption.
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 enhances the energy efficiency of HMDA separation, reducing both economic costs and the carbon footprint by optimizing the distillation pressure and using a specific alcohol for improved extraction and separation.
Implementation Method 1
extracting the HMDA-containing aqueous solution with a monovalent alcohol having 4 to 8 carbon atoms
Implementation Method 2
distilling the HMDA-containing alcoholic phase at a pressure of 100-600 mbar and separating the HMDA from the monovalent alcohol
Implementation Method 3
distilling the HMDA-containing alcoholic phase at a pressure of 100-600 mbar
Data Source
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AI summary
The present invention relates to a method for obtaining aqueous solutions containing hexamethylene diamine by depolymerizing polyamides and efficiently separating said hexamethylene diamine from the aqueous solution.