Azeotropic Distillation Separates HF from Fluoroolefins
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Solution Overview
Problem
The separation of hydrogen fluoride (HF) from fluoroolefins, such as 2,3,3,3-tetrafluoropropene (HFC-1234yf), is challenging due to the inefficiencies of existing methods like distillation and decantation, which often require large amounts of scrubbing solutions and result in excessive waste and wet products.
Innovation Solution
A process involving azeotropic distillation, where a mixture of HF and HFC-1234yf is fed to a distillation column, forming an azeotrope that condenses into two liquid phases, allowing for the recycling of enriched phases back into the column to separate and purify HF and HFC-1234yf, with optional use of an entrainer to enhance phase 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 invention utilizes phase transition of the azeotrope mixture into two liquid phases upon condensation. The distillate containing HF and fluoroolefin azeotrope is condensed to form an HF-rich liquid phase and a fluoroolefin-rich liquid phase, enabling separation without aqueous scrubbing solutions.
Solution Approach 2:
The invention employs an azeotrope-forming compound as an intermediary substance. This compound forms a heterogeneous azeotrope with HF that separates into two liquid phases upon condensation, acting as a mediator to facilitate separation without requiring large amounts of scrubbing solutions.
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 invention exploits the phase transition behavior of the azeotrope mixture. When the distillate is condensed, it automatically separates into two liquid phases with different compositions, enabling effective separation that conventional distillation cannot achieve alone.
Solution Approach 2:
The invention changes the physical parameters of the system by condensing the vapor phase into liquid phase, which triggers phase separation. This parameter change from vapor to liquid state enables the separation mechanism that makes conventional distillation ineffective.
3Reliability
If decantation is used to separate HF from fluoroolefins, then separation is attempted, but it requires large amounts of scrubbing solutions and produces wet product
Solution Approach 1:
The invention uses phase transition to create two immiscible liquid phases upon condensation. The HF-rich phase and fluoroolefin-rich phase separate naturally, allowing decantation without requiring large amounts of scrubbing solutions and producing drier products.
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 recovers HF and HFC-1234yf with reduced waste and energy consumption, improving the efficiency of separation and purification by leveraging the unique phase behavior of azeotropic mixtures.
Implementation Method 1
condensing the first distillate to form 2 liquid phases
Implementation Method 2
condensing the first distillate to form 2 liquid phases, being i) an HF-rich phase and ii) an HFC-1234yf-rich phase
Implementation Method 3
removing an azeotrope composition comprising HF and HFC-1234yf as a first distillate
Data Source
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AI summary
Disclosed herein are processes for separation of 2,3,3,3-tetrafluoropropene and hydrogen fluoride using azeotropic distillation. Additionally, disclosed are processes for separating mixtures of 2,3,3,3-tetrafluoropropene, hydrogen fluoride and 1,1,1,2,3-pentafluoropropane (HFC-245eb) and/or 1,1,1,2,2-pentafluoropropane (HFC-245cb) by azeotropic distillation.