Mixed-Conducting Membrane Reactor for Pure Hydrogen From Ammonia
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Solution Overview
Problem
The separation of hydrogen from nitrogen produced during ammonia transformation is inefficient and economically challenging, making it difficult to utilize ammonia as a surrogate for hydrogen transport.
Innovation Solution
An electrochemical reactor with a mixed conducting membrane is used to separate hydrogen from ammonia, where ammonia is introduced to the anode and water to the cathode, enabling hydrogen production through electrochemical pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ammonia is transformed to hydrogen through conventional methods, then hydrogen can be produced from ammonia, but the hydrogen is mixed with nitrogen and difficult to separate efficiently
Solution Approach 1:
The patent divides the ammonia transformation process into two separate electrochemical half-reactions occurring at different electrodes separated by an ion-exchange membrane. The anode performs ammonia oxidation while the cathode performs water reduction, physically separating hydrogen production from nitrogen generation and enabling high-purity hydrogen output.
Solution Approach 2:
The patent introduces an ion-exchange membrane as an intermediary between the anode and cathode compartments. This membrane selectively transports ions while preventing direct mixing of the anode effluent (containing nitrogen) with the cathode-produced hydrogen, thereby ensuring high hydrogen purity without requiring additional separation steps.
2Ease of operation
If ammonia is used as a surrogate for hydrogen transport, then hydrogen can be contained and transmitted easily, but additional transformation and separation steps are required
Solution Approach 1:
The patent extracts the hydrogen separation function from the ammonia transformation process by using the ion-exchange membrane to selectively transport hydrogen ions to the cathode side while blocking nitrogen and other byproducts. This extraction of pure hydrogen at the cathode eliminates the need for complex post-transformation separation systems.
3Manufacturing precision
If conventional electrolysis of water is used, then hydrogen can be produced with high purity, but ammonia cannot be utilized as a hydrogen source
Solution Approach 1:
The patent creates a multi-functional electrochemical cell that simultaneously achieves high-purity hydrogen production and ammonia utilization. The anode is designed to catalyze ammonia oxidation while the cathode produces pure hydrogen through water reduction, and the ion-exchange membrane connects these functions, making the system universally applicable to both ammonia conversion and pure hydrogen generation.
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
The method efficiently produces high-purity hydrogen without the need for additional separation steps, utilizing ammonia's energy density and avoiding the inefficiencies of traditional separation methods.
Implementation Method 1
hydrogen is generated from water electrochemically
Implementation Method 2
efficient electrochemical pathways
Implementation Method 3
the membrane is both electronically conducting and ionically conducting
Implementation Method 4
the membrane is both electronically conducting and ionically conducting
Implementation Method 5
ammonia cracking takes place in situ at the anode
Implementation Method 6
introducing an oxidant to the anode; wherein the oxidant comprises oxygen or air
Implementation Method 7
introducing a second stream to the cathode, wherein the second stream comprises water and provides a reducing environment for the cathode
Data Source
AI summary
Herein discussed is a method of producing hydrogen comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a membrane between the anode and the cathode, wherein the membrane is both electronically conducting and ionically conducting; (b) introducing a first stream to the anode, wherein the first stream comprises ammonia; (c) introducing an oxidant to the anode; and (d) introducing a second stream to the cathode, wherein the second stream comprises water and provides a reducing environment for the cathode; wherein hydrogen is generated from water electrochemically; wherein the first stream and the second stream are separated by the membrane; and wherein the oxidant and the second stream are separated by the membrane.