Separation Membrane Element Turbulent Flow Design
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Solution Overview
Problem
Current separation membrane elements for desalination and water treatment face challenges in achieving high fresh water production and removal performance over a long period, with issues related to fouling and concentration polarization.
Innovation Solution
A separation membrane element design featuring a feed-side channel material with a thickness of 0.15 mm to 0.50 mm, a permeate-side channel material with a cross-sectional area ratio of 0.4 to 0.75, and a configuration where the feed-side flow channel is perpendicular to the water collection tube, enhancing turbulent flow and reducing fouling, particularly by using a multilayer separation membrane with a cross-linked polymer and a porous supporting layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of feed-side channel material is reduced to increase fresh water production, then the membrane area per element increases, but the flow resistance increases and may cause operational issues
Solution Approach 1:
The feed-side channel material has non-uniform thickness distribution, with thinner regions (0.03-0.15mm) in areas requiring lower flow resistance and thicker regions (0.15-0.30mm) in areas requiring higher structural strength. This local variation optimizes both fresh water production and energy efficiency by matching thickness to local functional requirements.
Solution Approach 2:
The feed-side channel material incorporates flexible fibers (0.01-0.05mm diameter) that can dynamically adjust to flow conditions and pressure variations, allowing the channel structure to adapt its effective thickness and maintain optimal flow characteristics while supporting high membrane areas.
2Productivity
If the amount of separation membrane is increased to improve removal performance, then the membrane area increases, but the concentration polarization and fouling on membrane surface worsen
Solution Approach 1:
The feed-side channel material incorporates elastic fibers (0.05-0.20mm diameter) with specific elastic moduli that create micro-vibrations and turbulence in the feed flow, preventing stagnant zones and reducing concentration polarization on the membrane surface, thereby decreasing fouling while maintaining high removal performance.
Solution Approach 2:
The channel material design optimizes hydraulic flow patterns through controlled thickness variations and fiber arrangements, creating enhanced mixing and reduced boundary layer thickness on the membrane surface, which minimizes concentration polarization and fouling accumulation.
3Duration of action of stationary object
If the service life of separation membrane element is extended, then the structural strength must be maintained, but the fresh water production performance may degrade over time
Solution Approach 1:
The feed-side channel material combines cellulose fibers (0.03-0.10mm diameter) with specific crystallinity (30-70%) and degree of polymerization (100-500) to create a composite structure that provides both long-term structural stability and sustained hydrophilic properties, maintaining fresh water production performance over extended service life.
Solution Approach 2:
The channel material parameters (thickness, fiber diameter, crystallinity, degree of polymerization) are optimized to balance structural durability with flow performance, ensuring that mechanical strength is maintained over time while hydrophilic characteristics prevent fouling accumulation that would degrade productivity.
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 design achieves improved fresh water production and removal performance with reduced fouling and concentration polarization, maintaining high efficiency over a long period by minimizing the adhesion of salts and organic matter on the membrane surface.
Implementation Method 1
separation methods utilizing separation membrane elements have found increasing uses as processes for energy savings and conservation of resources. Separation membranes adopted in the separation methods utilizing separation membrane elements are classified into five groups according to their pore sizes and separation function, namely microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes and forward osmosis membranes.
Implementation Method 2
In order to improve the removal performance of the spiral-type separation membrane element, a channel material member and a spiral-type separation membrane element structure are proposed which can enhance the turbulent effect on the membrane surface and prevent the concentration polarization.
Implementation Method 3
the separation membrane has a value of A3/B (m2/sec2/MPa3) of 8.0×10−8 or more, in which A (m/sec/MPa) is a solution permeation coefficient and B (m/sec) is a solute permeation coefficient.
Data Source
AI summary
According to the present invention, it is possible to obtain a separation membrane element which has an element configuration having high fresh water production performance and high removal performance, has an improved membrane surface linear velocity whereby fouling due to hardly-soluble salts (scales) or organic matters is less likely to occur on the membrane surface particularly in high recovery ratio operation, and is excellent in fresh water production performance and removal performance over a long period of time.