Dual-MEA Hydrogen Purification Cell for High Purity With Less Complexity
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Solution Overview
Problem
Existing methods for purifying hydrogen gas to high purity (>99.99% by volume) are inefficient, costly, and complex, as they require multiple electrochemical pumps, membrane thickness increases, or gas compression, leading to limited purity and increased system complexity.
Innovation Solution
A dual membrane electrode assembly (DMEA) system that uses two MEAs in series, with each MEA containing an anode, electrolyte, and cathode, to oxidize and reduce hydrogen ions, enhancing purity by reducing impurity gases through a unique gas distribution and passage system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple electrochemical hydrogen pumps are used in series to increase hydrogen purity, then hydrogen purity is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple electrochemical pump functions into a single integrated cell stack where the cathode of one MEA serves as the anode of the next MEA. This merging eliminates the need for separate pumps, housings, and conduits while achieving the same purification effect through cascaded electrochemical reactions within a unified structure.
Solution Approach 2:
The shared electrode structure performs multiple functions: it acts as both a cathode for hydrogen evolution in one MEA and an anode for hydrogen oxidation in the next MEA. This multi-functionality reduces the number of components needed while maintaining the purification capability across multiple stages.
2Manufacturing precision
If membrane thickness is increased to reduce impurity diffusion, then hydrogen purity is improved, but hydrogen recovery decreases
Solution Approach 1:
The patent extracts hydrogen ions (protons) from the gas phase through the membrane and transfers them to the next stage, separating the hydrogen purification function from the bulk gas flow. This allows thin membranes to be used while still achieving high purity by continuously removing hydrogen ions that would otherwise diffuse through with impurities.
Solution Approach 2:
The patent introduces an intermediary electrochemical reaction stage where hydrogen ions are converted to hydrogen gas and then re-oxidized in the subsequent MEA. This intermediary process allows selective transport of hydrogen while blocking impurities, achieving high purity without requiring thick membranes that would reduce recovery.
3Manufacturing precision
If separate electrochemical pump cell stacks are used to purify hydrogen twice, then hydrogen purity is improved, but device complexity increases
Solution Approach 1:
The patent merges what would traditionally be two separate cell stacks into one integrated stack by sharing internal electrodes between MEAs. The gas flow passes sequentially through multiple MEAs within a single housing, eliminating the need for separate housings, cell stacks, feed conduits, and exhaust conduits that would be required for two independent purification stages.
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 DMEA system achieves hydrogen gas purity up to 100 times lower impurity content, with impurities reduced to at most 100 ppm, addressing the inefficiencies of existing methods by improving purity and reducing system complexity.
Implementation Method 1
the anode containing a catalyst adapted to oxidize the hydrogen gas to produce hydrogen ions and electrons
Implementation Method 2
an electrolyte positioned and adapted to receive and transfer the hydrogen ions produced by the anode
Implementation Method 3
the cathode containing a catalyst adapted to reduce the hydrogen ions transferred by the electrolyte to produce a gas stream having a higher hydrogen gas content
Data Source
AI summary
Hydrogen gas purifier electrochemical cells, systems for purifying hydrogen gas, and methods for purifying hydrogen gas are provided. The cells, systems, and methods employ double membrane electrode (DMEA) electrochemical cells that enhance purification while avoiding the complexity and cost of conventional cells. The purity of the hydrogen gas produced by the cells, systems, and methods can be enhanced by removing at least some intermediate gas impurities from the cells. The purity of the hydrogen gas produced by the cells, systems, and methods can also be enhanced be introducing hydrogen gas to the cells to replenish any lost hydrogen. Water electrolyzing electrochemical cells and methods of electrolyzing water to produce hydrogen gas are also disclosed.