Membrane Stack Lateral Fluid Supply for Electrodialysis
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Solution Overview
Problem
Existing membrane stacks for electrodialysis and reverse electrodialysis processes face high hydraulic resistances and inefficiencies due to the presence of spacers, turbulence promoters, and guiding devices, which hinder process efficiency and lead to fluid leakage and fouling.
Innovation Solution
A membrane stack design that supplies and discharges fluid substantially in the plane of the membrane, minimizing flow resistances and leakage by eliminating the need for distribution channels and spacers, and using profiled membranes with channels to enhance fluid flow and reduce short-cut currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If spacers, turbulence promoters and guiding devices are used in the membrane stack, then fluid distribution is improved, but hydraulic resistance increases and process efficiency decreases
Solution Approach 1:
The invention removes spacers, turbulence promoters, and guiding devices from the membrane stack, eliminating the components that cause high hydraulic resistance while maintaining fluid distribution through the membrane channels themselves
Solution Approach 2:
The invention integrates the fluid distribution function directly into the membrane channels, merging the previously separate functions of spacers and membranes into a unified structure that eliminates hydraulic resistance while maintaining distribution capability
2Strength
If spacers and guiding devices are present in the membrane stack, then structural support is provided, but ineffective area increases and fouling occurs
Solution Approach 1:
The invention removes spacers and guiding devices that create dead zones and ineffective areas where fouling occurs, eliminating the sources of contamination while maintaining structural integrity through the membrane channel design
Solution Approach 2:
The invention uses the porous structure of the membranes themselves to provide both structural support and fluid flow paths, eliminating the need for additional solid components that would create fouling-prone areas
3Ease of operation
If fluid is supplied from the top or bottom of the membrane stack, then distribution channels are required, but flow path length increases and hydraulic resistance increases
Solution Approach 1:
The invention changes the fluid supply direction from vertical (top or bottom) to lateral (side), allowing fluid to enter directly into the membrane channels at the point of use and eliminating long flow paths through distribution channels
Solution Approach 2:
The invention uses the membrane channels themselves as the intermediary for fluid distribution, eliminating the need for separate distribution channels and reducing the overall flow path length
4Ease of manufacture
If conventional membrane stack design is used, then manufacturing is simplified, but membrane surface area utilization is reduced due to ineffective areas
Solution Approach 1:
The invention merges the fluid distribution function with the membrane structure itself, allowing the entire membrane surface to be utilized for the separation process without ineffective areas created by spacers and guiding devices
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 design improves the efficiency of membrane-based processes by reducing hydraulic resistance, minimizing fouling, and reducing the need for cleaning operations, while also enhancing the effective use of membrane surface area and reducing electrical leakage.
Implementation Method 1
membrane based processes include electrodialysis (ED), reverse electrodialysis (RED) and other membrane processes
Implementation Method 2
a number of cation and anion exchange membranes that are alternately placed
Implementation Method 3
fluid supply and discharge means for supplying and discharging a fluid to the compartments such that the fluid is supplied and discharged substantially in the plane of the membrane
Implementation Method 4
In a reverse electrodialysis process the above process is reversed in order to generate electric energy
Data Source
AI summary
The present invention relates to a membrane stack and device for a membrane based process and method therefore. The membrane stack comprises: a number of membranes (78) forming compartments; and fluid supply and discharge means (80) for supplying and discharging a fluid to the compartments such that the fluid is supplied and discharged substantially in the plane of the membrane of the membrane stack. Preferably, the fluid supply and discharge means are provided on opposite sides of the membrane stack. Further, the invention relates to a method of forming the membranes (78).