Electrodialysis Stack Insulated Zone for Recessed Edge Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrodialysis stacks with recessed electrodes experience non-uniform current distribution, leading to high current density at the electrode's leading edge, causing damage to both the electrode and membrane, and reducing device efficiency.
Innovation Solution
Incorporating an electrically insulated zone that extends from the distribution manifold past the recessed edge of the electrode, redirecting current away from the edge to reduce or eliminate damage, ensuring the current density at the leading edge is within 150% of the bulk current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrodes are recessed from the distribution manifold, then current distribution becomes non-uniform with high current density at the leading edge, but this reduces shorting current and improves device efficiency
Solution Approach 1:
An electrically insulated zone is introduced at the leading edge of the recessed electrode to create a localized modification in current distribution. This insulated zone prevents excessive current concentration at the vulnerable leading edge while maintaining the overall recessed electrode configuration that reduces shorting current.
Solution Approach 2:
The electrically insulated zone acts as an intermediary element between the distribution manifold and the recessed electrode. It mediates the current flow by providing a controlled transition zone that prevents direct high-density current contact with the electrode edge, thereby protecting against damage while allowing current to reach the electrode surface.
2Productivity
If electrodes are recessed from the distribution manifold, then device efficiency improves, but current density at the leading edge increases causing accelerated damage
Solution Approach 1:
The electrically insulated zone creates a localized protective region at the leading edge of the electrode. This local modification allows the electrode to maintain its recessed configuration for high efficiency while the insulated zone specifically protects the vulnerable leading edge area from excessive current density damage.
Solution Approach 2:
The electrically insulated zone provides beforehand protection to the electrode leading edge by intercepting and redistributing current before it can concentrate and cause damage. This preventive measure extends the operational lifespan of the electrode and membrane by protecting them from accelerated degradation at the leading edge.
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 electrically insulated zone redistributes current effectively, reducing damage to the electrode and membrane, thereby enhancing the efficiency and longevity of the electrodialysis stack.
Implementation Method 1
an electrically insulated zone that overlaps with the electrically conductive fluid connection between the electrodes
Implementation Method 2
The majority of the current passes through the ion transport membranes, creating desalination and concentration of salts
Implementation Method 3
In an electrodialysis stack having full electrodes, the ionic current is driven through the stack by a pair of electrodes (anode and cathode)
Data Source
AI summary
The present disclosure provides an electrodialysis stack that may be used for the treatment of an electrically conductive solution. The stack includes two electrodes (at least one is a recessed electrode), a plurality of ion-transport membranes and stack spacers. The membranes and spacers are arranged between the electrodes to define electrodialysis cell pairs. The stack includes an electrically insulated zone that extends substantially from a distribution manifold past the recessed edge of the electrode and substantially from the recessed electrode to the opposite electrode for a distance that is about 8% to 100% of the total distance between the electrodes. The overlap distance that the electrically insulated zone extends past the recessed edge of the electrode is calculated as:distance in cm=(0.062 cm−1)*(exp(−60/total cp)*(area in cm2 of the manifold ducts of the concentrated stream at the recessed edge)+/−10%.