Electrochlorination Cell Hydrogen Abatement via Oxidant Injection

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Solution Overview

Problem

Electrochlorination systems produce hydrogen as a byproduct, which can lead to explosion hazards, reduce electrode efficiency, and cause mechanical failure due to embrittlement, necessitating costly gas-liquid separators and blowers.

Innovation Solution

Introduce an oxidizing agent, such as oxygen, into the chloride-containing aqueous solution to replace the hydrogen-generating cathode reaction, reducing hydrogen production and increasing energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If electrochemical reactions are used to generate sodium hypochlorite from sodium chloride and water, then disinfectant production is achieved, but hydrogen gas is produced as a byproduct creating explosion hazards

Engineering Contradiction:
Improvesodium hypochlorite generationVSAvoidhydrogen explosion hazard
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an oxidizing agent that converts the harmful hydrogen byproduct into useful disinfectant (hypochlorite) through chemical reaction. The hydrogen generated at the cathode is immediately oxidized by the introduced oxidizing agent, transforming the explosion hazard into additional disinfectant production.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent employs strong oxidizing agents (such as chlorine, chlorine dioxide, or ozone) to rapidly oxidize hydrogen at the cathode surface. This accelerated oxidation prevents hydrogen accumulation and converts it into water or hypochlorite, eliminating the explosion hazard while enhancing disinfectant generation.

Inventive Principle:
Principle #38Strong oxidants (Accelerated oxidation)

2Productivity

If hydrogen is produced in the electrochemical cell, then electrochemical reactions proceed, but electrode efficiency is reduced due to shielding from electrolyte contact

Engineering Contradiction:
Improveelectrochemical reaction rateVSAvoidelectrode shielding
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The oxidizing agent introduced into the system converts the harmful hydrogen shielding effect into a beneficial process by immediately reacting with hydrogen at the cathode surface. This prevents hydrogen bubble accumulation that would otherwise shield the electrode, while simultaneously generating additional hypochlorite disinfectant.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Duration of action of stationary object

If hydrogen diffuses into titanium electrodes, then electrochemical cell operation continues, but electrode mechanical failure occurs due to embrittlement

Engineering Contradiction:
Improveelectrode operational lifeVSAvoidelectrode mechanical strength
Core Design Contradiction:
Duration of action of stationary objectVSStrength

Solution Approach 1:

The patent applies preliminary anti-action by introducing the oxidizing agent upstream or at the cathode surface to prevent hydrogen from diffusing into the titanium electrode structure. The oxidizing agent reacts with hydrogen before it can penetrate the metal lattice, thereby preventing embrittlement and extending electrode life.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

By converting hydrogen into water or hypochlorite through oxidation, the system prevents hydrogen from causing embrittlement. The harmful hydrogen that would otherwise weaken the titanium electrode is transformed into a beneficial reaction that protects the electrode structure while producing additional disinfectant.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Object-affected harmful factors

If gas-liquid separators and blowers are installed to remove hydrogen, then safety is improved, but system cost increases

Engineering Contradiction:
Improvehydrogen removalVSAvoidsystem capital cost
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the hydrogen removal function from the physical separation equipment (gas-liquid separators and blowers) and transfers it to a chemical reaction process. By introducing the oxidizing agent, hydrogen is chemically converted into water or hypochlorite, eliminating the need for mechanical separation and reduction equipment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical hydrogen removal system (separators and blowers) with a chemical oxidation system. Instead of using mechanical means to separate and remove hydrogen gas, the oxidizing agent chemically converts hydrogen into non-hazardous products, substituting a simpler chemical process for complex mechanical equipment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Reduces hydrogen generation and voltage requirements, enhancing safety and efficiency by eliminating hydrogen accumulation and reducing energy consumption.

Implementation Method 1

Introduce an oxidizing agent, such as oxygen, into the chloride-containing aqueous solution to replace the hydrogen-generating cathode reaction

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

Electrochemical reactions for the generation of sodium hypochlorite from sodium chloride and water (electrochlorination)

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP3350130B1In-situ delivery systems for reaction product abatement in electrochemical cells
Publication Date: 2025.12.03 EVOQUA WATER TECHNOLOGIES LLC
  • EP3350130B1 patent drawingFigure 1A
  • EP3350130B1 patent drawingFigure 1B
  • EP3350130B1 patent drawingFigure 2A

AI summary

An electrochlorination system comprising an electrochemical cell including a housing having an inlet, an outlet, and an anode-cathode pair disposed within the housing, a source of a chloride-containing aqueous solution having an outlet fluidly connectable to the inlet of the electrochemical cell, and a source of an oxidizing agent fluidly connectable to the source of chloride-containing aqueous solution upstream of the electrochemical cell.