SO2 Depolarized Electrolyzer for Concurrent Acid and Hydrogen Production

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Solution Overview

Problem

Conventional sulfur dioxide depolarized electrolyzers primarily utilize sulfuric acid cyclically, limiting the simultaneous utilization of sulfuric acid and hydrogen as commodity chemicals, and face challenges such as high electrical potential requirements, sulfur dioxide crossover, and reduced control over sulfuric acid concentration and catalytic overpotential.

Innovation Solution

The sulfur dioxide depolarized electrolyzer system leverages electrochemical oxidation of sulfur dioxide to produce sulfuric acid and hydrogen concurrently, operating at lower electrical potential, minimizing sulfur dioxide crossover, and enhancing control over sulfuric acid concentration and catalytic overpotential through optimized catalyst loading, anolyte and catholyte flow paths, and pressurized operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sulfuric acid is utilized cyclically in conventional electrolyzers, then the system can maintain operation, but the simultaneous utilization of sulfuric acid and hydrogen as commodity chemicals is limited

Engineering Contradiction:

Improvesimultaneous utilization of sulfuric acid and hydrogenVSAvoidcommodity chemical production

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The electrolyzer system is divided into separate anolyte and catholyte circulation systems with independent flow paths. The anolyte stream handles sulfur dioxide to sulfuric acid conversion while the catholyte stream handles water to hydrogen conversion, allowing both products to be simultaneously utilized as commodity chemicals without cyclic interference

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrolyzer system is designed to produce both sulfuric acid and hydrogen as valuable commodity chemicals simultaneously, rather than cycling sulfuric acid. The system serves multiple functions: electrochemical oxidation of sulfur dioxide, electrochemical reduction of water, and simultaneous production of two marketable products for applications like fertilizer and metal extraction

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If conventional electrolyzers operate at standard electrical potential, then the system can function, but high electrical potential requirements increase energy consumption

Engineering Contradiction:

Improveelectrical energy consumptionVSAvoidelectrical potential requirement

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The system employs optimized catalyst loading and flow path configurations that change the electrochemical parameters of the reaction. The catalyst distribution and flow dynamics are tuned to reduce activation overpotential and improve reaction efficiency, thereby lowering the electrical potential requirement and reducing energy consumption

Inventive Principle:

Principle #35Parameter changes

3Productivity

If sulfur dioxide is processed in the electrolyzer, then sulfuric acid can be produced, but sulfur dioxide crossover occurs reducing efficiency

Engineering Contradiction:

Improvesulfuric acid production efficiencyVSAvoidsulfur dioxide crossover

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The harmful effect of sulfur dioxide crossover is addressed by extracting and removing it from the system. The catholyte circulation system is designed to minimize sulfur dioxide penetration into the hydrogen production zone, and any crossover is actively managed through flow control and separation mechanisms that prevent loss of sulfur dioxide and contamination of the hydrogen stream

Inventive Principle:

Principle #2Taking out (Extraction)

4Productivity

If catalyst loading is increased to improve reaction rate, then conversion efficiency improves, but catalytic overpotential increases

Engineering Contradiction:

Improveconversion efficiencyVSAvoidcatalytic overpotential

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

Instead of uniformly increasing catalyst loading throughout the system, the invention applies catalyst selectively in specific zones where it is most effective. The catalyst distribution is optimized locally in the anolyte flow path to maximize sulfur dioxide conversion while minimizing overall overpotential, creating different catalyst concentrations in different regions based on local reaction requirements

Inventive Principle:

Principle #3Local quality

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 reduces the environmental impact and cost of hydrogen production, improves cell efficiency and uptime, and enables the coproduction of sulfuric acid and hydrogen for multiple applications, such as fertilizer and metal extraction, with increased conversion efficiency and reduced byproduct formation.

Implementation Method 1

electrochemically oxidizing sulfur dioxide

Methodology Applied

Scientific EffectElectrochemical oxidation: Electrolysis

Implementation Method 2

electrochemically reducing water (e.g., protons) to hydrogen

Methodology Applied

Scientific EffectElectrochemical reduction: Electrolysis

Data Source

PatentUS20240271302A1Sulfur dioxide depolarized electrolysis and electrolyzer therefore

Publication Date: 2024.08.15 PEREGRINE HYDROGEN INC

AI summary

A method can include combusting a sulfur precursor in air to form sulfur dioxide, providing the sulfur dioxide to an electrolyzer with at least a threshold gauge pressure, providing water to the electrolyzer, and oxidizing the sulfur dioxide to sulfuric acid and reducing the water to hydrogen in the electrolyzer.