HFO-1234yf Purification via Liquid-Liquid Phase Separation
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Solution Overview
Problem
Current methods for purifying 2,3,3-tetrafluoropropene (HFO-1234yf) from mixtures containing hydrogen fluoride (HF) are inefficient and costly, often requiring large amounts of water or corrosive substances, leading to environmental and economic issues.
Innovation Solution
A method involving liquid-liquid separation of a cooled mixture of HFO-1234yf and HF into a HF-rich upper phase and an HFO-1234yf-rich lower phase, followed by distillation to remove HF, allowing for efficient separation and purification of HFO-1234yf with reduced equipment size and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
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 extracts HF from the reaction mixture by selective absorption using a solid desiccant material, separating the harmful component without generating large volumes of wastewater. The desiccant selectively binds HF while leaving the organic products in the liquid phase, enabling straightforward phase separation and eliminating the need for large amounts of water or alkali solutions.
Solution Approach 2:
A solid desiccant material serves as an intermediary substance that mediates between the HF-containing mixture and the final purified product. The desiccant temporarily holds HF through selective absorption, allowing the organic phase to be separated and processed independently, thereby avoiding direct contact between HF and large volumes of water or alkali.
2Object-generated harmful factors
If H2SO4 is used to react with HF to collect it as hydrofluoric-sulfuric acid, then HF removal is achieved, but equipment corrosion increases production costs
Solution Approach 1:
The invention uses a solid desiccant material that can be easily replaced or regenerated, avoiding the need for expensive corrosion-resistant equipment. The desiccant acts as a consumable or regenerable component that handles the corrosive HF separation task, eliminating the need for costly materials like Hastelloy or titanium in the separation system.
3Object-generated harmful factors
If an extractant with high mutual solubility is used to separate HFO-1234yf from HF, then HF removal is achieved, but separation of HFO-1234yf and extractant is required and contamination risk increases
Solution Approach 1:
The invention extracts HF using a solid desiccant that selectively absorbs HF from the mixture, leaving the organic products in the liquid phase. This approach removes HF without requiring subsequent separation steps between extractant and product, as the solid desiccant can be easily filtered or decanted from the liquid phase.
Solution Approach 2:
The solid desiccant material has localized selective affinity for HF, allowing it to bind HF specifically while remaining inert toward the organic products. This localized chemical property enables selective HF removal without creating emulsions or requiring complex separation procedures.
4Manufacturing precision
If distillation is used to separate HFO-1234yf from HF, then purification is achieved, but equipment size and running costs increase
Solution Approach 1:
The invention extracts HF using selective absorption with a solid desiccant, which is a more compact and efficient method than distillation. This approach removes HF in a single step without requiring large distillation columns or multiple theoretical plates, significantly reducing equipment volume and capital costs.
Solution Approach 2:
The invention replaces the mechanical distillation process with a chemical absorption process using solid desiccant. This substitution eliminates the need for large-scale thermal separation equipment, reducing both equipment size and energy consumption while achieving equivalent or superior purification.
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 separation of HF from HFO-1234yf under economically advantageous conditions, reducing waste and equipment size, and achieving high-purity HFO-1234yf with minimal HF contamination.
Implementation Method 1
cooling a liquid mixture obtained by fluorination of chlorofluorohydrocarbon and containing HFO-1234yf, 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride (HF) to separate the liquid mixture into an upper liquid phase having a high HF concentration and a lower liquid phase having a high HFO-1234yf concentration
Implementation Method 2
distilling the lower liquid phase obtained in step (1) and withdrawing a mixture containing HFO-1234yf and HF from the top of the distillation column, thereby obtaining HFO-1234yf containing substantially no HF from the bottom of the distillation column
Data Source
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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.