Azeotropic Distillation for HF and Fluoroolefin Separation
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Solution Overview
Problem
The separation of hydrogen fluoride (HF) from fluoroolefins, such as E-HFC-1234ze, is challenging due to the inefficiency of existing methods like distillation and decantation, which often require large amounts of scrubbing solutions and result in excessive waste.
Innovation Solution
A process involving azeotropic distillation, where the mixture of HF and E-HFC-1234ze is fed to a distillation column, forming an azeotrope that condenses into two liquid phases, allowing for the separation and recycling of either the HF-rich or E-HFC-1234ze-rich phase, with optional use of an entrainer to enhance separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous scrubbing is used to separate HF from fluoroolefins, then separation effectiveness is improved, but large amounts of scrubbing solutions are required and excessive waste is produced
Solution Approach 1:
The patent utilizes phase transition by condensing the azeotrope composition to form two liquid phases (HF-rich phase and fluoroolefin-rich phase) at temperatures below the azeotropic point. This phase separation enables effective HF removal without requiring large amounts of aqueous scrubbing solutions, thereby reducing waste production while maintaining separation effectiveness.
Solution Approach 2:
The patent employs an azeotrope composition as an intermediary medium between HF and fluoroolefins. By forming and then condensing this azeotrope, the system facilitates HF separation through phase transition rather than direct contact with large volumes of aqueous scrubbing solutions, thus achieving effective separation with reduced waste.
2Reliability
If conventional distillation is used to separate HF from fluoroolefins, then separation is attempted, but the method is very often ineffective
Solution Approach 1:
The patent overcomes the ineffectiveness of conventional distillation by utilizing phase transition. After distilling the mixture to obtain an azeotrope composition, the system condenses this composition to form two separable liquid phases. This phase transition step enables effective HF removal that conventional distillation alone cannot achieve, thereby improving both separation effectiveness and productivity.
Solution Approach 2:
The patent changes the temperature parameter by cooling the azeotrope composition below its azeotropic point to induce phase separation. This parameter change transforms the homogeneous azeotrope into two distinct liquid phases, enabling effective HF separation and resolving the inadequacy of conventional distillation methods.
3Reliability
If decantation is used to separate HF from fluoroolefins, then separation is attempted, but the method is very often ineffective
Solution Approach 1:
The patent enhances decantation effectiveness by first forming an azeotrope composition through distillation and then condensing it to create two distinct liquid phases. This pre-conditioning through phase transition ensures that subsequent decantation or phase separation is highly effective, overcoming the ineffectiveness of direct decantation methods.
Solution Approach 2:
The patent performs preliminary distillation to concentrate HF into an azeotrope composition before applying phase separation. This preliminary action prepares the mixture in a form that is much more amenable to efficient separation, thereby improving both effectiveness and productivity compared to direct decantation of the original mixture.
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 separates HF from E-HFC-1234ze, reducing waste and the need for large scrubbing solutions, while achieving high purity of both components through efficient recycling and phase separation.
Implementation Method 1
condensing the first distillate to form two liquid phases
Implementation Method 2
condensing the first distillate to form two liquid phases, being i) an HF-rich phase and ii) an E-HFC-1234ze-rich phase
Implementation Method 3
Processes for separation of 1,3,3,3-tetrafluoropropene from hydrogen fluoride by azeotropic distillation
Data Source
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AI summary
Disclosed herein is a process for the separation of HFC-1234ze and HF by azeotropic distillation. Additionally disclosed is a process for the separation of HFC1234ze, HFC-245eb and/or 245fa, and HF by azeotropic distillation.