Measurement techniques for the investigation of gas holdup and bubble size distribution in the anode circuit of PEM electrolyzers

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 in the anode circuit, resulting from the high current densities. The volume fraction of oxygen prevails over the volume fraction of hydrogen by a factor of 20. 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. Furthermore, the local instantaneous oxygen fraction represented by partially fine dispersed bubbles related to the full oxygen amount in the anode circuit is still unknown and should be investigated. Due to the development of new separation concepts with high separation efficiency, the measurement of gas holdup and bubble size are carried out using a capacitance wire-mesh sensor (WMS), optical channel body flow sensor, and optical microscope. This poster was prepared for the H2Giga status conference and provides an overview of measurement techniques used in the project.

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.