Seawater Electrolytic Cell Cathode Coating for Scale Prevention
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Solution Overview
Problem
Seawater chlorinators face significant challenges due to scale formation, which reduces disinfection efficiency and increases pressure drop, and existing solutions either complicate the system, reduce electrode lifetime, or are inefficient, especially in subsea applications where maintenance is costly.
Innovation Solution
An electrolytic cell with a cathode coated using a hydrolysable polymer and electrically conductive agents like graphene and carbon nanotubes, which degrades slowly to maintain a scale-free surface, ensuring continuous operation without the need for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional uncoated cathode is used in seawater electrolysis, then the device is simple and inexpensive, but scale forms on the cathode surface reducing disinfection efficiency and increasing pressure drop
Solution Approach 1:
The cathode is coated with a composite material consisting of hydrolysable polymer and electrically conductive agent. This composite coating provides both scale repellency through the hydrolysable polymer and electrical conductivity through the conductive agent, resolving the contradiction between preventing scale formation and maintaining device simplicity.
Solution Approach 2:
The invention changes the surface properties of the cathode by applying a coating with specific chemical and physical parameters. The hydrolysable polymer creates a surface that is repellent to inorganic scale-forming materials, while the electrically conductive agent ensures the surface maintains appropriate electrical conductivity for electrolysis, thus improving reliability without significantly increasing complexity.
2Reliability
If electrode polarity is reversed to remove scale deposits, then scale is removed from the cathode, but the electrodes are damaged and their lifetime is reduced
Solution Approach 1:
The hydrolysable polymer coating on the cathode creates a preliminary protective barrier that prevents scale from adhering to the electrode surface in the first place. This preliminary anti-action eliminates the need for polarity reversal to remove scale, thereby preserving electrode integrity and extending electrode lifetime while maintaining continuous scale-free operation.
3Reliability
If a non-conductive hydrophobic coating is applied to the cathode, then scale formation is reduced, but the coating must be very thin compromising electrolytic function
Solution Approach 1:
The coating is designed with local quality differentiation: the hydrolysable polymer provides scale repellency at the surface, while the electrically conductive agent is distributed within the coating matrix to ensure electrical conductivity. This local quality approach allows the coating to be sufficiently thick for durable scale protection while maintaining electrolytic function through the conductive agent network.
Solution Approach 2:
By combining hydrolysable polymer with electrically conductive agent in a composite coating, the invention overcomes the limitation of non-conductive coatings. The composite structure allows the coating to be thicker and more uniform without compromising electrical conductivity, as the conductive agent provides conductive pathways throughout the coating matrix.
4Reliability
If the cathode is cleaned mechanically by lifting the cell out of water, then scale is removed, but the system requires maintenance intervention and stops operation
Solution Approach 1:
The hydrolysable polymer coating on the cathode provides self-service by actively preventing scale adhesion through its chemical properties. The coating continuously resists scale formation without requiring external intervention, allowing the system to operate continuously without maintenance shutdowns while maintaining cathode cleanliness.
Solution Approach 2:
The coating provides continuous scale protection throughout the operation of the electrolytic cell. Unlike mechanical cleaning methods that require periodic shutdowns, the hydrolysable polymer coating maintains its scale-repellent properties continuously, ensuring uninterrupted disinfection operation while keeping the cathode clean.
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 solution effectively prevents scale formation, maintains high disinfection efficiency, and extends the operational life of the electrolytic cell, allowing for long-term subsea operation without maintenance, while maintaining electrical conductivity throughout its lifespan.
Implementation Method 1
the coating including a hydrolysable polymer and an electrically conductive agent
Implementation Method 2
the coating including a hydrolysable polymer and an electrically conductive agent
Implementation Method 3
Electrochemical production of oxidants via electro chlorinators and hydroxyl radical generators is well known
Implementation Method 4
oxidation reactions at the anode cause an acidic environment
Implementation Method 5
Water and oxygen reduction reactions near the cathode cause the release of oxidants
Implementation Method 6
the alkaline environment will typically induce precipitation of these ions, for example of calcium in the form of CaCO3 and magnesium in the form of Mg(OH)2
Data Source
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AI summary
There is disclosed an apparatus (100) for cleaning seawater, the apparatus (100) is configured to be positioned below the seawater surface and to take in surrounding seawater. The apparatus (100) comprises an electrolytic cell (10) comprising an anode and a cathode, wherein the cathode comprises a base material and a coating, the coating including a hydrolysable polymer and an electrically conductive agent. In a second aspect, the invention relates to a method for cleaning seawater for an injection into an injection well by means of an apparatus (100) according to the first aspect of the invention, the method including the steps of: placing the apparatus (100) under water in a stream of water to be cleaned; supplying power to the electrolytic cell (10) in order to generate an oxidating agent; letting the oxidating agent react with biologic material in the stream of water; injecting the cleaned water into an injection well.