A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers
The crossover of the product gases hydrogen and oxygen in alkaline electrolyzer operation is a critical factor, severely limiting the operational window in terms of current density and pressure. In prior experiments, it was found that a large degree of oversaturation of the reaction products in the...
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MDPI AG
2025-07-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/15/7/206 |
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| author | Diogo Loureiro Martinho Torsten Berning |
| author_facet | Diogo Loureiro Martinho Torsten Berning |
| author_sort | Diogo Loureiro Martinho |
| collection | DOAJ |
| description | The crossover of the product gases hydrogen and oxygen in alkaline electrolyzer operation is a critical factor, severely limiting the operational window in terms of current density and pressure. In prior experiments, it was found that a large degree of oversaturation of the reaction products in the liquid electrolyte phase leads to high amounts of crossover. We are proposing to reduce this amount of oversaturation by introducing micro-cracks in the Zirfon diaphragm. These cracks are meant to induce the formation of hydrogen and oxygen bubbles on the respective sides, and thereby reduce the oversaturation and amount of crossover. In theory, the size of the bubble corresponds to the size of the cracks, and from our computational fluid dynamics simulations, we conclude that the bubbles should be as large as possible to minimize the ohmic resistance in the electrolyte phase. The results suggest that an increase in bubble diameter from 50 microns to 150 microns results in a 10% higher current density at a cell voltage of 2.1 V. |
| format | Article |
| id | doaj-art-139e48a1e7274a2c9258216636fefd03 |
| institution | DOAJ |
| issn | 2077-0375 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
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| series | Membranes |
| spelling | doaj-art-139e48a1e7274a2c9258216636fefd032025-08-20T02:47:17ZengMDPI AGMembranes2077-03752025-07-0115720610.3390/membranes15070206A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline ElectrolyzersDiogo Loureiro Martinho0Torsten Berning1Green Hydrogen Systems, 6000 Kolding, DenmarkAAU Energy, Aalborg University, 9220 Aalborg, DenmarkThe crossover of the product gases hydrogen and oxygen in alkaline electrolyzer operation is a critical factor, severely limiting the operational window in terms of current density and pressure. In prior experiments, it was found that a large degree of oversaturation of the reaction products in the liquid electrolyte phase leads to high amounts of crossover. We are proposing to reduce this amount of oversaturation by introducing micro-cracks in the Zirfon diaphragm. These cracks are meant to induce the formation of hydrogen and oxygen bubbles on the respective sides, and thereby reduce the oversaturation and amount of crossover. In theory, the size of the bubble corresponds to the size of the cracks, and from our computational fluid dynamics simulations, we conclude that the bubbles should be as large as possible to minimize the ohmic resistance in the electrolyte phase. The results suggest that an increase in bubble diameter from 50 microns to 150 microns results in a 10% higher current density at a cell voltage of 2.1 V.https://www.mdpi.com/2077-0375/15/7/206alkaline water electrolysisZirfon diaphragmhydrogen crossoversupersaturationmicro-cracksbubble diameter |
| spellingShingle | Diogo Loureiro Martinho Torsten Berning A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers Membranes alkaline water electrolysis Zirfon diaphragm hydrogen crossover supersaturation micro-cracks bubble diameter |
| title | A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers |
| title_full | A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers |
| title_fullStr | A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers |
| title_full_unstemmed | A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers |
| title_short | A Conceptual Approach to Reduce the Product Gas Crossover in Alkaline Electrolyzers |
| title_sort | conceptual approach to reduce the product gas crossover in alkaline electrolyzers |
| topic | alkaline water electrolysis Zirfon diaphragm hydrogen crossover supersaturation micro-cracks bubble diameter |
| url | https://www.mdpi.com/2077-0375/15/7/206 |
| work_keys_str_mv | AT diogoloureiromartinho aconceptualapproachtoreducetheproductgascrossoverinalkalineelectrolyzers AT torstenberning aconceptualapproachtoreducetheproductgascrossoverinalkalineelectrolyzers AT diogoloureiromartinho conceptualapproachtoreducetheproductgascrossoverinalkalineelectrolyzers AT torstenberning conceptualapproachtoreducetheproductgascrossoverinalkalineelectrolyzers |