Supercritical Ethanol Separation via Stepwise Pressure Reduction
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Solution Overview
Problem
Existing supercritical extraction methods result in significant solvent loss due to rapid pressure reduction, leading to inefficient ethanol recovery during the separation process.
Innovation Solution
A solvent separation method involving two flash vessels arranged in series, where the pressure of the first flash vessel is maintained at 40-100 bar and the second flash vessel at 1-30 bar, allowing for stepwise pressure reduction and minimizing solvent vaporization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid pressure reduction is used in the flash vessel, then separation efficiency is improved, but solvent loss by vaporization increases
Solution Approach 1:
The single flash vessel is divided into two separate flash vessels operating at different pressure levels. The first flash vessel operates at high pressure (40-100 bar) for initial separation, while the second flash vessel operates at low pressure (1-30 bar) for final separation. This segmentation allows the system to achieve both efficient separation and minimal solvent vaporization loss by controlling pressure reduction in stages rather than rapidly in one step.
2Device complexity
If single-stage pressure reduction is used, then device complexity is reduced, but solvent recovery rate decreases
Solution Approach 1:
The system uses two flash vessels connected in series, where the first flash vessel performs initial separation at high pressure and the second flash vessel completes separation at low pressure. This segmented approach increases solvent recovery rate to 95% or more by preventing rapid vaporization, while maintaining relatively simple device structure through the straightforward series connection of two standard flash vessel components.
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 reduces solvent loss and increases the recovery rate of ethanol to 95% or more, enhancing the overall efficiency of the solvent recovery process.
Implementation Method 1
Supercritical fluids refer to fluids at temperatures or pressures above their critical points. The supercritical fluids have intermediate unique properties between gas and liquid such as viscosity and diffusion coefficient similar to gas, and density close to liquid, thereby being applied to various fields such as supercritical extraction
Implementation Method 2
Since the solubility of CO2 is higher in ethanol than in water, only ethanol may be selectively extracted
Implementation Method 3
This fluid flows through a pressure reducing valve and flows into a flash vessel, where the pressure of the fluid is rapidly reduced and the fluid is separated into CO2 and liquid ethanol, respectively
Implementation Method 4
where the pressure of the fluid is rapidly reduced and the fluid is separated into CO2 and liquid ethanol
Implementation Method 5
The CO2 recovered in a gas phase is subjected to a heat exchange/pressurization process and then used for supercritical extraction
Implementation Method 6
The CO2 recovered in a gas phase is subjected to a heat exchange/pressurization process
Data Source
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AI summary
The present invention relates to a separation method and a separation apparatus of a solvent extracted by supercritical extraction, wherein two or more flash vessels are arranged in series to decrease the pressure of the solvent stepwise, thereby minimizing the amount of the solvent lost by vaporization to obtain an effect of increasing the solvent recovery rate.