Selective Brine Salt Extraction Using a Regenerated Organic Phase
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Solution Overview
Problem
Existing methods for extracting salts from saltwater or brine are energy-intensive, costly, and environmentally impactful, with low purity yields and high reagent consumption, particularly in desert or landlocked areas, and lack a direct extraction process for neutral salts.
Innovation Solution
A process involving a hydrophobic organic phase with specific organic compounds to selectively extract cations and anions from brine, using a series of mixers, decanters, and heat exchangers to achieve high purity and low energy consumption, with a closed-loop system for recycling the organic phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If thermal crystallization or evaporation processes are used to separate salts from brine, then salt separation is achieved, but energy consumption increases significantly (682 kWhth/ton at 20°C for water evaporation)
Solution Approach 1:
The patent extracts the salt separation process from thermal/evaporation methods and implements it through selective liquid-liquid extraction using organic compounds. The organic phase selectively extracts target salts (NaCl, KCl, LiCl) from brine at controlled temperatures, eliminating the need for high-energy evaporation while achieving efficient salt separation through chemical selectivity rather than thermal energy input.
Solution Approach 2:
The patent changes the fundamental parameter of separation from thermal energy input to chemical selectivity parameters. By adjusting organic phase composition, temperature (operating at lower temperatures compared to evaporation), and phase ratios, the process achieves salt separation without requiring the high energy input of traditional evaporation, thereby resolving the energy consumption vs. extraction efficiency contradiction.
2Use of energy by stationary object
If solar evaporation ponds are used to avoid energy costs, then water evaporation energy Opex becomes zero, but local water consumption increases considerably (more than 90% of brine water is evaporated)
Solution Approach 1:
The patent takes out the water removal function from evaporation processes and replaces it with selective salt extraction into an organic phase. The organic compounds selectively solubilize target salts and transfer them to the organic phase, leaving the bulk water in the aqueous phase. This eliminates the need to evaporate 90%+ of water while still achieving salt concentration and separation, thereby resolving the contradiction between zero energy cost and excessive water consumption.
Solution Approach 2:
The organic phase acts as an intermediary carrier that selectively transports target salts from the aqueous brine phase without requiring water evaporation. This intermediary mechanism achieves salt separation and concentration while preserving the water in the brine, thus avoiding both the energy input of thermal evaporation and the water loss of solar evaporation ponds.
3Productivity
If ion exchange methods are used to extract salts, then selective extraction is achieved, but reagent consumption and operating costs increase due to regeneration requirements
Solution Approach 1:
The patent implements a regeneration system where the organic phase, after extracting salts from brine, is contacted with a regeneration solution to recover the extracted salts and restore the organic phase for reuse. This closed-loop approach eliminates continuous reagent consumption, as the organic extractant is repeatedly regenerated and reused, thereby resolving the contradiction between selective extraction capability and reagent consumption associated with ion exchange methods.
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
Achieves selective extraction of salts with high yield and purity, minimal energy and water consumption, and zero reagent use, suitable for a wide concentration range and various salt types.
Implementation Method 1
at least a second hydrophobic organic compound which selectively extracts the cation of the salt to be extracted and has a complexation constant for the cation to be extracted whose log K value, in methanol at 25° C., is greater than 1
Implementation Method 2
at least a first hydrophobic, protic organic compound which solvates the anion of the salt to be extracted
Implementation Method 3
the mixture is sent to a so-called initial extraction decanter-separator, in order to obtain: a brine from which salt to be extracted has been removed; and an organic phase loaded with salt to be extracted
Implementation Method 4
the organic phase loaded with salt to be extracted, heated in the so-called 'organic' heat exchanger
Data Source
AI summary
The present invention relates to a process for the selective extraction of a salt to be extracted from a brine to be treated containing the said salt to be extracted, characterized in that: the brine to be treated (S1) is sent to an initial extraction stirrer-mixer (1a) into which a liquid hydrophobic organic phase is also introduced, the said brine and the said liquid hydrophobic organic phase are mixed in the said initial extraction stirrer-mixer (1a), and the mixture is sent to an initial decanter-separator (1d, 1dc), in order to obtain: a brine from which salt to be extracted has been removed; and an organic phase loaded with salt to be extracted; the brine from which the salt to be extracted has been removed is recovered; the organic phase loaded with salt to be extracted is sent to an initial washing stirrer-mixer-decanter-centrifugal separator (5a, 5dc or 7a, 7dc), in order to obtain a purified organic phase loaded with salt to be extracted, which is sent to a so-called “organic” heat exchanger (1e) in which it is heated before being sent to a so-called initial “regeneration” column (1c; 2c), in which a countercurrent exchange is carried out with hot water at a higher temperature than that of the initial brine, in order to obtain: a water containing the salt to be extracted; and a regenerated organic phase, having lost the salt to be extracted; the regenerated organic phase is recycled to the initial extraction stirrer-mixer (1a).