Supercritical CO2 Extraction of PFPE Oil from Grease Matrices
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Solution Overview
Problem
There is a need for a cost-effective and environmentally friendly process to separate and recover perfluoropolyether (PFPE) oil from lubricating greases, as existing methods are inefficient and generate waste, particularly in aerospace applications where high-temperature performance and chemical stability are critical.
Innovation Solution
A process involving the use of liquid or supercritical carbon dioxide as a solvent, combined with an extraction aid material, to extract PFPE oil from lubricating greases, ensuring minimal contamination from thickeners and other additives, with a yield of at least 75 wt% and minimal thickener content in the recovered oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional multi-stage extraction processes are used to extract PFPE from lubricating grease, then extraction completeness may be improved, but process complexity and cost increase significantly
Solution Approach 1:
The patent extracts the valuable PFPE oil from the grease matrix using a simple single-stage extraction process with supercritical CO2, removing only the necessary component without requiring complex multi-stage processes. The supercritical fluid selectively dissolves the PFPE oil while leaving the thickener and additives behind, achieving effective separation in one step.
Solution Approach 2:
The patent utilizes parameter changes by transitioning CO2 from gaseous to supercritical state through controlled pressure and temperature adjustments. This single parameter change enables the solvent to penetrate the grease matrix effectively and selectively extract PFPE oil, simplifying the overall extraction process while maintaining high completeness.
2Quantity of substance
If conventional extraction methods are used, then PFPE oil can be recovered, but environmental pollution and waste generation occur
Solution Approach 1:
The patent converts the typically harmful or wasteful extraction process into an environmentally beneficial operation. By using supercritical CO2, a non-toxic and recyclable solvent, the process eliminates the need for harmful organic solvents. The CO2 can be recovered and reused, transforming what would be waste into a beneficial循环 resource, thus recovering PFPE oil without environmental pollution.
Solution Approach 2:
The patent replaces conventional mechanical or chemical extraction methods that generate waste with a supercritical fluid extraction system. The supercritical CO2 acts as a clean alternative to traditional solvents, providing effective PFPE oil recovery without the harmful byproducts or waste streams associated with conventional methods.
3Productivity
If simple extraction processes are used, then cost and time are reduced, but extraction yield and purity decrease
Solution Approach 1:
The patent exploits phase transitions of CO2 between gaseous and supercritical states to achieve both high extraction yield and purity in a single stage. By controlling pressure and temperature, the CO2 transitions to a supercritical state for effective extraction, then returns to gaseous state for easy separation and solvent recovery. This phase transition mechanism ensures complete PFPE oil extraction while maintaining high purity and enabling rapid process completion.
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
The process effectively separates and recovers PFPE oil with high yield and purity, maintaining its valuable properties, while being economically and environmentally sustainable, suitable for reuse in high-performance applications.
Implementation Method 1
contacting a solvent comprising a liquid or supercritical carbon dioxide with the lubricating grease comprising a thickener, an extraction aid material, and the perfluoropolyether in an extraction zone to form an extraction solution comprising an extracted perfluoropolyether
Data Source
Figure 1
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AI summary
This disclosure relates to a process for extracting a perfluoropolyether. The process involves: (a) contacting a solvent comprising a liquid or supercritical carbon dioxide with a lubricating grease comprising a thickener, an extraction aid material, and the perfluoropolyether in an extraction zone to form an extraction solution comprising an extracted perfluoropolyether; and (b) recovering the extracted perfluoropolyether from the extraction solution; wherein the recovered extracted perfluoropolyether comprises no more than about 2 wt % of the thickener.