Electrochemical Hydrogen Separation via Membrane-Electrode Assembly

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Solution Overview

Problem

Current methods for separating hydrogen from reaction mixtures, such as nonoxidative dehydroaromatization, are energy-intensive and mechanically demanding, often requiring high pressures and complex apparatus, which limits their efficiency and increases costs.

Innovation Solution

An electrochemical process using a gastight membrane-electrode assembly with a selectively proton-conducting membrane and electrode catalysts to oxidize hydrogen on one side and reduce it or react with oxygen on the other, allowing for hydrogen separation without relying on pressure differences, thus reducing mechanical stress and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If hydrogen separation is performed using conventional methods (pressure swing adsorption, hydrogen-permeable membranes), then hydrogen can be removed from the reaction mixture, but the process requires high pressure differences, complex apparatus, and high energy consumption

Engineering Contradiction:
Improvehydrogen removal efficiencyVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by stationary object

Solution Approach 1:

The patent replaces mechanical separation methods (pressure swing adsorption, pressure-driven membrane separation) with an electrochemical system. Instead of using pressure differences to drive hydrogen through membranes or through adsorption cycles, the invention uses electrochemical reactions at membrane-electrode assemblies to selectively remove hydrogen. This substitution eliminates the need for high-pressure compression equipment and complex mechanical separation apparatus, directly reducing energy consumption and mechanical complexity

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

Solution Approach 2:

The invention changes the operating parameters from high-pressure mechanical processes to low-pressure electrochemical processes. By applying electrochemical potentials to membrane-electrode assemblies, hydrogen is removed through electrochemical reactions rather than pressure-driven diffusion or adsorption. This parameter change from pressure-driven to potential-driven separation allows operation at lower pressures while maintaining effective hydrogen removal

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If hydrogen separation is performed using hydrogen-permeable membranes with high diffusion rates, then separation performance is improved, but mechanical stability demands increase and compression apparatus are required

Engineering Contradiction:
Improveseparation performanceVSAvoidapparatus complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces pressure-driven membrane separation with electrochemical membrane-electrode assemblies. Instead of relying on pressure differences to achieve hydrogen permeation through membranes, the invention uses electrochemical reactions at the membrane surfaces. This eliminates the need for compression apparatus and reduces mechanical stability demands on the membrane system, while maintaining high separation performance through selective electrochemical hydrogen removal

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

3Quantity of substance

If pressure swing adsorption is used for hydrogen removal, then hydrogen can be separated from the reaction mixture, but the process becomes technically complicated and requires adsorbents and pressure cycling equipment

Engineering Contradiction:
Improvehydrogen separationVSAvoidprocess complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent replaces the mechanically complex pressure swing adsorption process with a simpler electrochemical system. Instead of cycling through adsorption and desorption phases with pressure changes and multiple adsorbent beds, the invention uses continuous electrochemical hydrogen removal at membrane-electrode assemblies. This substitution eliminates the need for pressure cycling equipment, multiple adsorbent vessels, and complex control systems, directly reducing process complexity while maintaining effective hydrogen separation

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

This process effectively separates hydrogen at lower pressures, improves energy balance, and increases the yield of desired products by shifting reaction equilibria, providing high-purity hydrogen or usable energy, depending on the mode of operation.

Implementation Method 1

a gastight membrane-electrode assembly comprising at least one selectively proton-conducting membrane

Methodology Applied
Scientific EffectProton conduction: Conduction (electrical)

Implementation Method 2

at least one electrode catalyst on each side of the membrane, where at least part of the hydrogen present in the reaction mixture R is oxidized to protons over the anode catalyst on the retentate side of the membrane

Methodology Applied
Scientific EffectElectrochemical oxidation: Oxidation

Implementation Method 3

the protons are, after passing through the membrane to the permeate side, reduced to hydrogen over the cathode catalyst

Methodology Applied
Scientific EffectElectrochemical reduction: Reduction

Implementation Method 4

gastight membrane-electrode assembly comprising at least one selectively proton-conducting membrane

Methodology Applied
Scientific EffectSelective permeation: Semipermeable Membrane

Data Source

PatentUS8729331B2Method for electrochemically removing hydrogen from a reaction mixture
Publication Date: 2014.05.20 BASF SE

AI summary

The invention relates to a process for the electrochemical separation of hydrogen from a hydrogen-comprising reaction mixture R by means of a gastight membrane-electrode assembly comprising at least one selectively proton-conducting membrane and at least one electrode catalyst on each side of the membrane, where at least part of the hydrogen present in the reaction mixture R is oxidized to protons over the anode catalyst on the retentate side of the membrane and the protons are, after passing through the membrane to the permeate side,I reduced to hydrogen over the cathode catalyst and/orII reacted with oxygen over the cathode catalyst to form water, with the oxygen originating from an oxygen-comprising stream O which is brought into contact with the permeate side of the membrane,and also a reactor equipped with at least one membrane-electrode assembly.