R22–HFP Extraction Distillation with High-Flash-Point Solvents
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Solution Overview
Problem
Existing methods for separating chlorodifluoromethane (R22) and hexafluoropropylene (HFP) are inefficient due to the formation of azeotropic or quasi-azeotropic compositions, and polar organic solvents with low flash points complicate the separation process.
Innovation Solution
A method involving the use of chlorine-containing compounds such as methylene chloride, chloroform, and trichloroethylene as extraction solvents with high flash points or no flash point, which are added in specific ratios to form mixtures with R22 and HFP, followed by extraction distillation to separate R22 and HFP effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate R22 and HFP based on boiling point difference, then separation is attempted, but separation efficiency is poor due to azeotropic composition formation
Solution Approach 1:
The patent introduces a polar organic solvent as an intermediary substance to facilitate separation. The solvent forms an extraction distillation system where it selectively interacts with one component (R22 or HFP) through polarity differences, enabling effective separation despite the azeotropic composition that prevents direct distillation separation.
2Manufacturing precision
If polar organic solvents with low flash points are used for extraction distillation, then separation efficiency improves, but safety hazards increase due to low flash point
Solution Approach 1:
The patent changes the critical parameter of the solvent from low flash point to high flash point while maintaining the necessary polarity for effective separation. This parameter change allows the system to achieve both high separation efficiency and improved safety by selecting solvents with flash points above 60°C that still possess the required polar characteristics for extraction distillation.
3Object-affected harmful factors
If compounds with high flash points are used as extraction solvents, then safety improves, but separation efficiency may decrease
Solution Approach 1:
The patent applies local quality by selecting solvents that possess specific local characteristics (high polarity in the molecular structure) while having overall high flash point properties. The solvent's molecular structure is chosen to have polar groups that provide strong selective interaction with the target component, ensuring efficient separation despite the high flash point.
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 approach achieves high-efficiency separation of R22 and HFP by reducing the relative volatility between the two compounds, allowing for the production of high-purity HFP and concentrated R22 through multiple distillation steps.
Implementation Method 1
a mixing step of obtaining a mixture for extraction, which is a mixture of a first mixture including chlorodifluoromethane and hexafluoropropylene and an extraction solvent
Implementation Method 2
an extraction distillation step of distilling the mixture for extraction to respectively obtain a first distillate including hexafluoropropylene as a main component, and a first bottom product including the extraction solvent as a main component and including chlorodifluoromethane
Data Source
AI summary
A method for separating R22 and HFP includes a mixing step of obtaining a mixture for extraction which is a mixture of a first mixture including R22 and HFP and an extraction solvent including at least one chlorine-containing compound selected from the group consisting of methylene chloride, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, hexachloroethane, trichloroethylene, and tetrachloroethylene, and an extraction distillation step of distilling the mixture for extraction to respectively obtain a first distillate including HFP as a main component, and a first bottom product including the extraction solvent as a main component and including R22.