Experimental investigation of fluid dynamics during gas-liquid swirl separation for a wide working range using a swirl element

The cost-effective production of large amounts of green hydrogen using a new generation of proton exchange membrane (PEM) electrolyzers generates very high gas fractions, resulting from the high current densities. Hence, the shift of operating membrane conditions in the anode circuit into new and hitherto incomprehensible areas occurs. The mass fraction of oxygen prevails over the mass fraction of hydrogen by a factor of 8. Thus, the space and material requirements for conventional separators are very high. The main goal for the separation process of oxygen from the two-phase flow mixture is a completely gas-free operation fluid before the water enters the heat exchanger. This requires the optimization of oxygen separation technologies. For this purpose, a vertically arranged separator on the pilot scale was built up at Helmholtz -Zentrum Dresden – Rossendorf, which is based on the principle of swirl separation. This contribution provides results on the experimental study of different types of swirl geometries, which have the main impact on the separation efficiency of the process. Different types of swirl geometries are investigated and the development of the gas core and its stability are analyzed for single and two-phase flow at various flow rates of the gas and the liquid. Project The authors acknowledge the financial support by the Federal Ministry of Education and Research of Germany in the programme ”H2GIGA. Project identification number: 03HY123E.