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A Technical Analysis of the H 2 Purification Trains Downstream of Alkaline Electrolyzers

Author

Listed:
  • Elvira Spatolisano

    (GASP—Group on Advanced Separation Processes & GAS Processing, Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy)

  • Laura A. Pellegrini

    (GASP—Group on Advanced Separation Processes & GAS Processing, Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy)

Abstract

In view of achieving decarbonization targets, green hydrogen has emerged as a promising low-emission alternative. Typically, green hydrogen is produced by splitting water using various electrolysis technologies powered by renewable energy. Among these, alkaline electrolyzers have been proven as suitable for large-scale applications, operating effectively in alkaline environments under near-atmospheric pressure levels and temperatures. Once produced, H 2 must undergo purification for use in industrial and mobility sectors, with particularly stringent purification requirements for fuel applications. Despite the relevance of H 2 purification due to its usage as an energy carrier, no comprehensive analyses of H 2 purification trains downstream of H 2 production are available in the literature. To fill this gap, the aim of this work is to perform a detailed technical assessment of purification trains downstream of alkaline water electrolyzers, considering KOH removal, oxygen removal, compression and dehydration. Different case studies are discussed, focusing on the alkaline electrolyzer operating pressure (i.e., atmospheric or higher) and considering the application of H 2 in both the industrial and mobility sectors. The design and methodology of the process were developed within the Aspen Plus ® simulation environment, to support the electrolyzers’ integration in industrial settings.

Suggested Citation

  • Elvira Spatolisano & Laura A. Pellegrini, 2025. "A Technical Analysis of the H 2 Purification Trains Downstream of Alkaline Electrolyzers," Energies, MDPI, vol. 18(11), pages 1-15, May.
  • Handle: RePEc:gam:jeners:v:18:y:2025:i:11:p:2886-:d:1668807
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    References listed on IDEAS

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    1. Wang, Jingyi & Yang, Jinbin & Feng, Yu & Hua, Jing & Chen, Zhengjian & Liao, Mei & Zhang, Jingran & Qin, Jiang, 2025. "Comparative experimental study of alkaline and proton exchange membrane water electrolysis for green hydrogen production," Applied Energy, Elsevier, vol. 379(C).
    2. Zhang, Tao & Song, Lingjun & Yang, Fuyuan & Ouyang, Minggao, 2024. "Research on oxygen purity based on industrial scale alkaline water electrolysis system with 50Nm3 H2/h," Applied Energy, Elsevier, vol. 360(C).
    3. Sooin Kwon & Seongyong Eom & Gyungmin Choi, 2023. "Effects of Operating Conditions on the Oxygen Removal Performance of the Deoxo Chamber in the Water Electrolysis System," Energies, MDPI, vol. 16(18), pages 1-13, September.
    4. Bensmann, B. & Hanke-Rauschenbach, R. & Müller-Syring, G. & Henel, M. & Sundmacher, K., 2016. "Optimal configuration and pressure levels of electrolyzer plants in context of power-to-gas applications," Applied Energy, Elsevier, vol. 167(C), pages 107-124.
    5. Anna Król & Monika Gajec & Jadwiga Holewa-Rataj & Ewa Kukulska-Zając & Mateusz Rataj, 2024. "Hydrogen Purification Technologies in the Context of Its Utilization," Energies, MDPI, vol. 17(15), pages 1-38, August.
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    Cited by:

    1. Arkadiusz Małek, 2025. "Low-Emission Hydrogen for Transport—A Technology Overview from Hydrogen Production to Its Use to Power Vehicles," Energies, MDPI, vol. 18(16), pages 1-32, August.

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