Electrolysis Apparatus Plastic Component Longevity

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Solution Overview

Problem

Plastic components in electrolysis apparatuses used for oxygen-containing alkali metal hydroxide solutions undergo progressive material changes, leading to leaks and reduced plant availability due to contact with lye, especially at elevated temperatures and pressures.

Innovation Solution

Adjusting the oxygen content and pressure of the aqueous alkali metal hydroxide solution in the electrolysis process, with an O2 amount between 0 and 25 mg/L and an absolute pressure of 1.2 to 3.5 bar, and maintaining a temperature greater than 40°C, to extend the longevity of plastic components and prevent material changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plastic components are used for lye-contacting plant parts to achieve chemical resistance and electrical insulation, then corrosion resistance and electrical insulation are improved, but material changes occur over time leading to leaks and reduced reliability

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidservice life of plastic components

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by controlling the oxygen content of the electrolyte (maintaining O2 saturation at or below 80% of equilibrium value) and adjusting operational parameters like temperature and pressure. This creates a controlled chemical environment that reduces oxidative stress on the plastic components, thereby extending their service life while maintaining chemical resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates an inertified electrolyte environment by reducing the oxygen content through nitrogen purging or other degassing methods. This inert atmosphere prevents oxidative degradation of the plastic components, allowing them to maintain their chemical resistance and structural integrity for extended periods

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Productivity

If operating temperature is increased above 40°C to improve electrolysis efficiency, then productivity is improved, but material changes in plastic components accelerate leading to leaks

Engineering Contradiction:

Improveelectrolysis efficiencyVSAvoidmaterial stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent employs parameter changes by simultaneously controlling multiple variables: maintaining reduced oxygen content (≤80% saturation) while allowing elevated temperatures (>40°C). The low oxygen environment compensates for the increased thermal stress, enabling high-temperature operation without accelerating plastic degradation

Inventive Principle:

Principle #35Parameter changes

3Productivity

If operating pressure is increased above ambient pressure to improve process efficiency, then productivity is improved, but material changes in plastic components accelerate leading to leaks

Engineering Contradiction:

Improveprocess efficiencyVSAvoidmaterial stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by controlling the combined effect of pressure and oxygen content. By maintaining low oxygen levels in the electrolyte, the system can operate at elevated pressures without accelerating the oxidative degradation of plastic components, thus preserving material stability while improving process efficiency

Inventive Principle:

Principle #35Parameter changes

4Productivity

If oxygen content in electrolyte is increased to improve half-cell reaction efficiency, then electrolysis performance is improved, but oxidative degradation of plastic components accelerates

Engineering Contradiction:

Improveelectrolysis performanceVSAvoidoxidative degradation

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent creates an inertified electrolyte environment by reducing dissolved oxygen to ≤80% of saturation. This inert atmosphere eliminates the harmful oxidative effect on plastic components while maintaining sufficient oxygen for the electrochemical reactions at the electrodes, as oxygen is supplied directly at the electrode surfaces rather than through bulk electrolyte dissolution

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 adjustment significantly reduces material changes in plastic components, preventing leaks and extending the operational lifespan of electrolysis apparatuses beyond two years, ensuring higher plant availability and reliability.

Implementation Method 1

gaseous oxygen is introduced into the electrolyte in contact with said electrode

Methodology Applied

Scientific EffectGas dissolution: Absorption (physical)

Implementation Method 2

the pressure and temperature of the alkali metal hydroxide solution and the O2 amount therein is adjusted

Methodology Applied

Scientific EffectPressure control: Pressure Increase

Implementation Method 3

maintaining a temperature greater than 40°C

Methodology Applied

Scientific EffectTemperature control: Heating

Data Source

PatentUS20230349059A1Apparatus and method for performing electrolysis

Publication Date: 2023.11.02 COVESTRO DEUTSCHLAND AG

AI summary

The invention relates to an apparatus and a method for performing electrolysis with an originally oxygen-containing alkali hydroxide solution as an electrolyte precursor, wherein the pressure and temperature of the alkali hydroxide solution and the O2 content thereof are set.