HFO-1234yf Purification by Cooling Phase Separation and Distillation
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Solution Overview
Problem
Current methods for purifying 2,3,3-tetrafluoropropene (HFO-1234yf) from mixtures with hydrogen fluoride (HF) are costly, environmentally unfriendly, and require large amounts of water or corrosive materials, leading to increased production and equipment costs due to the need for extensive wastewater management and equipment corrosion.
Innovation Solution
A method involving cooling a liquid mixture of HFO-1234yf and HF to separate into distinct liquid phases, followed by distillation to remove HF, allowing for efficient separation of HFO-1234yf with reduced impurities and minimal HF content, utilizing azeotropic or non-azeotropic mixtures to optimize the distillation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water or alkali solution is used to adsorb HF from the mixture, then HF removal is achieved, but a large amount of industrial wastewater is discharged
Solution Approach 1:
The invention changes the physical state and concentration parameters by cooling the mixture to -30°C or lower, causing phase separation into HF-rich and HFO-1234yf-rich layers. This parameter change enables direct separation without requiring large volumes of water or alkali solutions, thus eliminating the wastewater discharge problem while maintaining effective HF removal.
Solution Approach 2:
The invention utilizes phase transition by cooling the liquid mixture below -30°C to induce liquid-liquid phase separation. The mixture separates into two distinct phases: an upper HF-rich phase and a lower HFO-1234yf-rich phase. This phase transition enables clean separation of HF from the product without introducing external reagents that would create wastewater.
2Reliability
If H2SO4 is used to react with HF to collect it as hydrofluoric-sulfuric acid, then HF removal is achieved, but equipment corrosion increases
Solution Approach 1:
The invention extracts HF from the mixture through phase separation based on differential solubility at low temperatures. By cooling the mixture to -30°C or lower, HF is extracted into a separate rich phase that can be easily separated from the HFO-1234yf product phase, eliminating the need for corrosive H2SO4 and its associated equipment corrosion problems.
Solution Approach 2:
The invention uses temperature as an intermediary parameter to achieve separation. By controlling the temperature to be -30°C or lower, the system creates conditions where HF and HFO-1234yf exhibit different solubilities, enabling separation without requiring chemical intermediaries like H2SO4 that would cause corrosion.
3Reliability
If extractant is used to separate HFO-1234yf from HF, then HF removal is achieved, but additional separation step and contamination risk are introduced
Solution Approach 1:
The invention applies self-service by utilizing the inherent property of the HFO-1234yf/HF mixture to separate automatically through phase separation at low temperatures. The system uses its own components' differential solubility characteristics to achieve separation without requiring external extractants, additional separation steps, or complex control systems.
Solution Approach 2:
The invention changes the temperature parameter to -30°C or lower to trigger phase separation. This parameter change enables the mixture to separate into HF-rich and product-rich phases automatically, eliminating the need for extractants and additional separation equipment, thus simplifying the overall process.
4Reliability
If distillation is used to separate HFO-1234yf from HF, then purification is achieved, but large equipment size is required
Solution Approach 1:
The invention performs preliminary action by cooling and phase separating the mixture before distillation. By pre-separating the mixture into HF-rich and HFO-1234yf-rich phases at -30°C or lower, the subsequent distillation step only needs to process the smaller HFO-1234yf-rich phase, significantly reducing the required distillation column size while maintaining effective purification.
Solution Approach 2:
The invention segments the separation process into two stages: first phase separation at low temperature to divide the mixture into HF-rich and product-rich phases, then distillation of the smaller product-rich phase. This segmentation reduces the distillation column size by eliminating the need to handle the entire original mixture volume.
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 the simple and economically advantageous separation of HF from HFO-1234yf, reducing production costs and environmental impact by minimizing the use of corrosive substances and wastewater, while efficiently obtaining high-purity HFO-1234yf with reduced impurities.
Implementation Method 1
cooling a liquid mixture containing HFO-1234yf and HF to separate the liquid mixture into an upper liquid phase having a high concentration of HF and a lower liquid phase having a high concentration of HFO-1234yf
Implementation Method 2
subjecting the lower liquid phase to a distillation operation and withdrawing a mixture containing HFO-1234yf and HF from a top of a distillation column
Data Source
AI summary
The present invention provides a method for purifying HFO-1234yf, comprising the steps of (1) cooling a liquid mixture containing HFO-1234yf and HF to separate the mixture into a upper liquid phase having a high concentration of HF and a lower liquid phase having a high concentration of 2,3,3,3-tetrafluoropropene; and (2) subjecting the lower liquid phase obtained in step (1) to a distillation operation to withdraw a mixture containing HFO-1234yf and HF from a top of a distillation column, thereby obtaining substantially HF-free HFO-1234yf from a bottom of the distillation column. According to the present invention, HF and HFO-1234yf contained in a mixture containing HF and HFO-1234yf can be separated under simple and economically advantageous conditions.