Effect of natural gas impurities on electrochemical hydrogen compression and strategies for mitigation

International Journal of Hydrogen Energy, vol. 170, pp. 150980

Abstract

Admixing of H 2 into the natural gas grid is a viable option for mid-term transportation. Electrochemical H 2 compressors (EHCs) separate H 2 from methane but are prone to poisoning due to impurities. This study compares low- and high-temperature EHCs regarding their tolerance towards natural gas impurities, focusing on the underexplored contaminants NH 3 and H 2 S and mitigation strategies. The impact of impurities was evaluated using 5 h chronopotentiometry, cyclic voltammetry, and electrochemical impedance spectroscopy. Low-temperature EHC (70 °C) showed an increase of up to 200 % in cell potential, while the increase remained below 6 % for high-temperature EHC (120 °C), when operated with CO 2 , CO, or H 2 S . When diluting the H 2 / H 2 S mixture in the high-temperature EHC with CH 4 , oscillations and an increase in cell potential were observed, which was mitigated when operating at 160 °C or via electro-oxidation. The results establish a foundation for long-term stability testing in natural gas.

Authors 4

1. Wibke Zängler Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Chemical Process Engineering, Forckenbeckstr. 51, Aachen, 52074, Germany

2. Nick Semrau Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Chemical Process Engineering, Forckenbeckstr. 51, Aachen, 52074, Germany

3. Matthias Weßling Aachen DWI - Leibniz Institute for Interactive Materials

   RWTH Aachen University · DWI – Leibniz Institute for Interactive Materials

   Affiliation as printed

   DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, Aachen, 52074, Germany

   RWTH Aachen University, Chemical Process Engineering, Forckenbeckstr. 51, Aachen, 52074, Germany

4. Robert Keller corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Chemical Process Engineering, Forckenbeckstr. 51, Aachen, 52074, Germany