Selective Ionic Liquid Absorption for Azeotropic Refrigerant Separation
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Solution Overview
Problem
Existing refrigerant mixtures, particularly azeotropic and near-azeotropic mixtures, complicate recycling and disposal due to their constant composition during phase changes, making it difficult to separate components like R-32 from R-125, R-143a, and R-134a, leading to inefficient recycling and potential greenhouse gas emissions.
Innovation Solution
The use of ionic liquids with non-fluorinated anions to selectively absorb one component over another in azeotropic mixtures by optimizing mass basis selectivity ratios, allowing for the separation of refrigerants like R-125 and R-32 through exposure to specific temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate azeotropic mixtures, then separation based on boiling point differences is achieved, but separation fails because azeotropic mixtures have constant composition during phase changes
Solution Approach 1:
The patent changes the separation mechanism from relying on boiling point differences to relying on selective absorption properties of ionic liquids. By changing the physical-chemical parameters of the separation medium (using ionic liquids with specific cations and non-fluorinated anions), the process can differentiate between components of azeotropic mixtures that have identical vapor-liquid equilibrium compositions.
Solution Approach 2:
The patent introduces ionic liquids as an intermediary substance that mediates the separation process. These ionic liquids act as a selective absorbing medium that interacts differently with different refrigerant components, enabling separation without direct reliance on the components' inherent physical property differences.
2Ease of manufacture
If conventional recycling methods are used for azeotropic mixtures, then recycling process is simplified, but component recovery is lost due to inability to separate components
Solution Approach 1:
The patent extracts specific refrigerant components from the azeotropic mixture through selective absorption by ionic liquids. By taking out individual components (such as R-32 or R-125) selectively, the process enables component recovery while maintaining recycling feasibility.
Solution Approach 2:
The patent segments the azeotropic mixture into individual components through sequential selective absorption steps. Different ionic liquids can be used in sequence to absorb different components, effectively dividing the mixture into separable parts that can be individually recovered and reused.
3Quantity of substance
If ionic liquids with fluorinated anions are used, then absorption capacity is high, but selectivity between different fluorocarbons is reduced
Solution Approach 1:
The patent applies local quality by using non-fluorinated anions in the ionic liquid structure. This specific local modification of the ionic liquid's chemical composition creates a selective interaction environment that differentiates between fluorocarbon components based on their molecular structures, achieving both absorption and selectivity.
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 enables high-purity separation of refrigerant components, facilitating recycling and reducing greenhouse gas emissions by allowing for the recovery and reuse of lower-GWP refrigerants.
Implementation Method 1
exposing an azeotropic mixture comprising a first (hydro)fluorocarbon and a second (hydro)fluorocarbon to an ionic liquid at a temperature and a pressure at which the ionic liquid absorbs more of one of the first and second (hydro)fluorocarbons than another
Data Source
AI summary
Processes for separating an azeotropic mixture are provided. In an embodiment, such a process comprises exposing an azeotropic mixture comprising a first (hydro)fluorocarbon and a second (hydro)fluorocarbon to an ionic liquid comprising a cation and a non-fluorinated anion at a temperature and a pressure at which the ionic liquid absorbs more of one of the first and second (hydro)fluorocarbons than another of the first and second (hydro)fluorocarbons as determined on a mass basis to form a (hydro)fluorocarbon-containing ionic liquid and a processed azeotropic mixture.