Separated Electrochemical Cell Layout for Low-Hydrogen Chlorination

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Solution Overview

Problem

Conventional electrochlorination systems face challenges with cathodic scaling and hydrogen gas generation, limiting the efficiency and safety of sodium hypochlorite production, and require costly gas-liquid separators to manage hydrogen gas.

Innovation Solution

The system employs an electrochemical cell with separate chambers and an ion-permeable membrane to prevent electrolyte mixing, uses an oxidant like oxygen to suppress hydrogen generation, and implements pH control, polarity reversal, and recirculation to enhance sodium hypochlorite production efficiency and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional electrochlorination systems are used to produce sodium hypochlorite, then the production process can be implemented, but hydrogen gas is generated and cathodic scaling occurs, requiring additional gas-liquid separators and reducing system efficiency

Engineering Contradiction:
Improvesodium hypochlorite production efficiencyVSAvoidhydrogen gas generation and cathodic scaling
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The electrochemical cell is divided into two separate chambers (anode chamber and cathode chamber) that are spatially separated and connected only through an ionic connection. This segmentation prevents the mixing of electrolytes between chambers and isolates the harmful effects (hydrogen gas generation at cathode, scaling at anode) from the product formation zone, allowing efficient sodium hypochlorite production without the negative side effects interfering with the process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful effects (hydrogen gas generation and cathodic scaling) are extracted and isolated into a separate cathode chamber that is physically disconnected from the anode chamber where sodium hypochlorite is produced. The ionic connection allows ion transfer necessary for electrochemical reactions while preventing the transfer of harmful byproducts to the product chamber, effectively removing the harmful factors from the main production process

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If gas-liquid separators are added to manage hydrogen gas, then hydrogen gas can be managed, but system complexity and cost increase

Engineering Contradiction:
Improvehydrogen gas managementVSAvoidsystem equipment requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydrogen gas management function is extracted from the main system by isolating it in a separate cathode chamber. The ionic connection acts as a barrier that prevents hydrogen gas from entering the anode chamber where sodium hypochlorite is produced, eliminating the need for additional gas-liquid separators while maintaining reliable hydrogen gas containment

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ionic connection serves as an intermediary element between the anode and cathode chambers. It allows necessary ion transfer for electrochemical reactions to proceed while simultaneously acting as a barrier that prevents harmful substances (hydrogen gas, scaled electrolyte) from passing between chambers, thus managing hydrogen gas without requiring complex additional equipment

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach effectively reduces hydrogen gas formation, minimizes scaling, and enhances sodium hypochlorite generation efficiency while reducing the need for additional equipment, thus improving system performance and safety.

Implementation Method 1

The ionic connection comprises an ion-permeable membrane. The ion-permeable membrane is selectively permeable to monovalent ions.

Methodology Applied
Scientific EffectIon-permeable membrane selective permeability: Semipermeable Membrane

Implementation Method 2

an electrochemical cell with separate chambers and an ion-permeable membrane to prevent electrolyte mixing, uses an oxidant like oxygen to suppress hydrogen generation

Methodology Applied
Scientific EffectElectrochemical reaction: Electrolysis

Implementation Method 3

a use is provided comprising the electrochemical cell in fluid communication with a source of seawater for electrochemically generate NaOCl from the seawater

Methodology Applied
Scientific EffectElectrochemical reaction: Electrolysis

Data Source

PatentEP3593398B1Electrochemical cell
Publication Date: 2025.10.01 EVOQUA WATER TECHNOLOGIES LLC
  • EP3593398B1 patent drawingFigure 1
  • EP3593398B1 patent drawingFigure 2
  • EP3593398B1 patent drawingFigure 3

AI summary

An electrochemical cell including a first chamber having an anode, a second chamber having a cathode, at least one ionic connection between the first chamber and the second chamber, such that liquid electrolyte from the first chamber is prevented from mixing with liquid electrolyte in the second chamber is provided. The first chamber and the second chamber can be arranged in parallel and positioned remotely from each other. An electrochemical system including the electrochemical cell, and first and second sources of saline aqueous solutions is also provided. Water treatment systems are also provided. A method of operating an electrochemical cell including introducing first and second saline aqueous solutions into first and second chambers of the electrochemical cell, and applying a current across the anode and the cathode to generate first and second products, respectively is also provided. A method of facilitating operation of an electrochemical cell is also provided.