Forward Osmosis System with Membrane Distillation for Solvent Separation
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Solution Overview
Problem
Existing systems for separating products from solutions, such as seawater desalination, face inefficiencies and complexity in achieving reliable solvent separation, particularly due to reliance on hydraulic pressure and cumbersome designs.
Innovation Solution
A forward osmosis system with semipermeable membrane walls allows solvent separation driven by osmotic pressure gradients, using a draw solution with higher osmotic potential to facilitate efficient product recovery, incorporating modular flow passages and stages for compact and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reverse osmosis using hydraulic pressure is used for solvent separation, then separation can be achieved, but the system becomes complex and less efficient
Solution Approach 1:
The patent inverts the conventional reverse osmosis approach by using forward osmosis, where the driving force is osmotic pressure gradient rather than hydraulic pressure. The draw solution with higher osmotic potential naturally draws solvent through the semipermeable membrane, eliminating the need for complex high-pressure pumps and control systems while maintaining separation efficiency
Solution Approach 2:
The patent changes the operating parameter from hydraulic pressure to osmotic pressure gradient. By selecting a draw solution with appropriate osmotic potential (higher than the feed solution), the system achieves solvent transport through the membrane without mechanical pressure, simplifying the overall system design
2Productivity
If multiple flow passages are added to increase separation power, then efficiency increases, but device complexity increases
Solution Approach 1:
The patent combines multiple flow passages into a single integrated module where feed solution and draw solution flow passages are interlaced with semipermeable membrane walls. This modular design allows multiple passages to be stacked in series, increasing separation power while maintaining a compact and simple overall structure that does not proportionally increase complexity
Solution Approach 2:
The patent arranges flow passages in a three-dimensional stacked configuration rather than expanding horizontally. Multiple feed and draw solution flow passages are stacked in series with membrane walls between them, allowing the system to increase separation power by adding passages in the vertical dimension without significantly increasing the footprint or operational complexity
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 enhances separation efficiency and yield by leveraging osmotic pressure, enabling a compact and simple design capable of handling multiple flow passages, and allows for the use of various draw solutions, including saline and organic compounds, effectively addressing the limitations of reverse osmosis.
Implementation Method 1
The inner space of a respective flow passage conducting the solution to be processed is at least partly bounded by a semipermeable membrane wall which is permeable for the solvent of the solution to be processed, but not for the substance dissolved therein, and wherein at least one flow passage conducting the draw solution is bounded on mutually oppositely disposed sides by membrane walls which are associated with two adjacent flow passages conducting the solution to be processed such that solvent from the solution to be processed arrives in the adjacent flow passages conducting the draw solution through the membrane walls
Implementation Method 2
The solute contained in the draw solution has a higher so-called osmotic potential than the solute contained in the solution to be processed. From a specific concentration of the draw solution onward, the osmotic potential on the permeate side is always higher than the osmotic potential on the side of the solution to be processed
Data Source
AI summary
The invention relates to a system for separating a product contained as solvent in a solution to be processed, comprising at least one forward osmosis device (816) through which the solution to be processed and a draw solution flow, and a device connected downstream thereof for obtaining the product (56, 62) from the diluted draw solution exiting the forward osmosis device, wherein the forward osmosis device comprises at least one flow channel conducting the solution to be processed and at least one flow channel conducting the draw solution, the inner space of a respective flow channel conducting the solution to be processed is delimited at least partially by a semi-permeable membrane wall that is permeable to the solvent of the solution to be processed but not to the substance dissolved therein, and at least one flow channel conducting the draw solution is delimited on opposite sides by membrane walls that are associated with two adjoining flow channels conducting the solution to be processed, such that solvent from the solution to be processed passes through the membrane walls into the adjoining flow channels conducting the draw solution.