Disposable Membrane Stacks for Ion Exchange
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ion exchange units (IEUs) face challenges with laborious disassembly and reassembly in plate-and-frame configurations and are prone to catastrophic failures due to limited compartments in spiral-wound configurations, which increase maintenance costs and energy consumption.
Innovation Solution
Disposable cross-flow membrane stacks with flat, textured cation and anion exchange membranes that are permanently secured together, eliminating the need for high compression forces and separate spacers, allowing for easy alignment and reducing fouling and pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If plate-and-frame configuration is used with bolted end plates, then membranes can be cleaned or replaced individually, but disassembly and reassembly becomes laborious and difficult requiring careful alignment
Solution Approach 1:
The membrane stack is divided into individual membrane elements that can be independently removed and replaced. Each membrane is separated from others by spacers, allowing targeted maintenance of specific membranes without disassembling the entire stack, thus enabling easy repair while maintaining operational simplicity.
Solution Approach 2:
The membranes, spacers, and gaskets are pre-assembled in the correct alignment configuration during manufacturing. This preliminary assembly eliminates the need for careful field alignment during maintenance operations, as components are designed to self-align or snap into place, reducing labor and complexity while enabling easy membrane replacement.
2Reliability
If high compression forces are applied to prevent leakages in plate-and-frame units, then sealing is improved, but components experience high stress and compartments are compressed restricting liquid flow
Solution Approach 1:
The gasket material properties are modified to achieve effective sealing at lower compression forces. By selecting elastomeric materials with appropriate durometer ratings and cross-sectional geometries, the system achieves reliable leakage prevention with reduced clamping force, thereby avoiding compartment compression and maintaining adequate liquid flow through the stack.
Solution Approach 2:
The gaskets are designed as disposable components that can be easily replaced rather than maintained under high stress conditions. This approach allows the use of simpler, less expensive gasket materials that would not withstand repeated high-compression cycles, eliminating flow restriction issues while maintaining sealing reliability through periodic replacement.
3Ease of manufacture
If spiral-wound configuration with few long compartments is used, then manufacturing is simplified, but blockage in one compartment causes catastrophic failure and pressure drop increases
Solution Approach 1:
The stack is segmented into multiple short compartments rather than a few long ones. This segmentation is achieved by placing spacers at regular intervals along the membrane length, creating numerous small flow channels. If one compartment becomes blocked, the others continue to operate, preventing catastrophic failure and maintaining system reliability while keeping manufacturing relatively simple.
4Ease of operation
If spacers are used to maintain membrane separation, then liquid flow is maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The spacer and gasket functions are merged into a single integrated component. The spacer incorporates sealing features that allow it to both maintain membrane separation for liquid flow and provide leakage prevention, eliminating the need for separate gasket components and reducing overall device complexity while maintaining operational effectiveness.
Solution Approach 2:
The spacer is designed to perform multiple functions simultaneously: maintaining membrane separation, guiding liquid flow, providing structural support, and enabling sealing. This multi-functional design eliminates the need for separate dedicated components for each function, reducing device complexity and manufacturing cost while ensuring proper liquid flow through the stack.
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
Facilitates rapid and convenient assembly of IEUs with reduced maintenance and energy consumption, enhancing operational longevity and cost-effectiveness by maintaining efficient ion transport and flow without the need for extensive spacer elements.
Implementation Method 1
The cation-permeable membranes and/or the anion-permeable membranes have a textured surface profile which keep said membranes apart and/or from touching each other
Implementation Method 2
The membrane stacks comprise alternating dilution compartments and concentration compartments, each compartment comprising a cation-permeable membrane wall and an anion-permeable membrane wall
Implementation Method 3
the concentrated ionic solution is typically sea water or a brine and the solution of lower ionic concentration is typically fresh or brackish water
Implementation Method 4
by applying an electric field ions are forced from the solution in the dilution compartments to the solution in the concentration compartments
Implementation Method 5
In RED, the concentrated ionic solution is typically sea water or a brine and the solution of lower ionic concentration is typically fresh or brackish water
Data Source
AI summary
A disposable, crossflow membrane stack suitable for use in an ion exchange unit, the stack comprising alternate dilution compartments and concentration compartments, each compartment being defined by a flat cation-permeable membrane (2) and a flat anion-permeable membrane (1) and at least two edges along which the cation-permeable and an anion-permeable membranes are permanently secured together wherein the cation-permeable membranes and/or the anion-permeable membranes have a textured surface profile which keep said membranes apart and/or from touching each other and wherein the edges secured together define the direction in which liquid may flow through the compartments. Also claimed are ion exchange units comprising the stack, optionally comprising a quick-release securement means to allow facile attachment and release of modular units comprising the stacks.