Azeotropic Distillation for HF and Fluoroolefin Separation
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Solution Overview
Problem
The separation of hydrogen fluoride (HF) from fluoroolefins is challenging due to the inefficiency of existing methods like distillation and decantation, which often require large amounts of scrubbing solutions and produce excessive waste, necessitating a more effective separation process.
Innovation Solution
A process involving azeotropic distillation, where a mixture of HF and fluoroolefin is fed to a distillation column, forming an azeotrope that is condensed into two liquid phases, allowing for the recycling of either the HF-rich or fluoroolefin-rich phase back into the column, enabling efficient separation of HF from fluoroolefin.
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 invention utilizes phase transition of the azeotrope mixture into two liquid phases upon condensation. The distillate is condensed to form an HF-rich phase and a fluoroolefin-rich phase, which separate due to immiscibility. This phase separation enables effective HF removal without requiring large amounts of scrubbing solutions, directly resolving the contradiction between separation effectiveness and substance loss.
Solution Approach 2:
The azeotrope acts as an intermediary medium that facilitates separation. By forming and condensing the azeotrope, the system creates two immiscible liquid phases that can be easily separated. This intermediary approach achieves effective HF removal while minimizing scrubbing solution consumption and waste production.
2Ease of operation
If conventional distillation and decantation are used to separate HF from fluoroolefins, then separation is attempted, but the methods are very often ineffective
Solution Approach 1:
The invention employs phase transition by condensing the azeotrope distillate to form two immiscible liquid phases. This phase separation creates a natural division between HF-rich and fluoroolefin-rich phases, making the separation process both simple to operate and highly effective. The condensed phases can be easily decanted or separated using standard equipment.
Solution Approach 2:
The invention changes the physical parameters of the mixture by condensing the vapor-phase azeotrope into liquid phases at different temperatures and pressures. This parameter change transforms the mixture into two separable liquid phases, simultaneously improving ease of operation and separation effectiveness.
3Reliability
If aqueous scrubbing is used to remove HF, then HF removal is achieved, but the product becomes wet and must be dried
Solution Approach 1:
The invention uses phase transition to separate HF into an HF-rich liquid phase while the fluoroolefin-rich phase remains substantially free of HF and moisture. This eliminates the need for drying the product, as the fluoroolefin is recovered in a dry state directly from the separated phases.
Solution Approach 2:
The azeotrope serves as an intermediary that carries HF into the HF-rich phase during condensation. This intermediary mechanism achieves effective HF removal while leaving the fluoroolefin product dry and free from moisture contamination.
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 fluoroolefin, reducing waste and the need for large scrubbing solutions, achieving efficient and economical separation by utilizing azeotropic distillation and recycling phases within the process.
Implementation Method 1
removing an azeotrope composition comprising HF and fluoroolefin as a first distillate
Implementation Method 2
condensing the first distillate to form two liquid phases
Implementation Method 3
condensing the first distillate to form two liquid phases, being i) an HF-rich phase and ii) a fluoroolefin-rich phase
Data Source
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AI summary
The present disclosure relates to a process for separating a fluoroolefin from a mixture comprising hydrogen fluoride and fluoroolefin, comprising azeotropic distillation both with and without an entrainer. In particular are disclosed processes for separating any of HFC-1225ye, HFC-1234ze, HFC-1234yf or HFC-1243zf from HF.