Members

IMMC

Kevin Van Droogenbroek
PhD student
Ir. at UCL in 2022
Contact

Main project: 2-phase CFD simulations of electrolyte-bubble interactions during alkaline water electrolysis
Funding: Région Wallonne
Supervisor(s): Joris Proost

In today’s world, concern is growing about the future of energy. Despite very ambitious international climate goals by 2050, global energy-related carbon dioxide (CO2) emissions keep increasing. In order to tackle this problem, hydrogen (H2) seems to be the right solution since it is a way to produce, store, move and use energy in a clean way. However, 95% of the actual hydrogen production is made of grey hydrogen, e.g. H2 produced from fossil energies, which leads to high CO2 emissions in the atmosphere. One way to decarbonise this energy vector is to produce green hydrogen by means of renewable energies (solar panels, wind turbines, etc). This is where my research project funded by the Walloon region comes in, focusing on the production of green hydrogen by alkaline water electrolysis (AWE).

In general, AWE is characterised by the use of two planar electrodes separated by a certain distance and operating in a liquid alkaline electrolyte solution (e.g. KOH, potassium hydroxide). However, the efficiency of the process can be improved by the use of 3D electrodes in a zero-gap cell configuration. This configuration is the one that will be used in the scope of this research and it is depicted in Figure 1. The chemical reactions taking place at the cathode and at the anode are also highlighted.

More specifically, the work will consist in the fluid mechanical modeling of liquid and gaseous flows within alkaline electrolysis cells filled with 3D porous structures. The study of liquid electrolyte flow and of gaseous hydrogen bubble formation and escape will allow to optimise the performance of the electrolyser. Computational Fluid Dynamics (CFD) is a powerful numerical tool that will be used during this project to determine the optimal flow parameters required to homogenise the electrolyte flow (to take advantage of the full specific area provided by the electrodes) while favouring hydrogen bubbles removal from the electrolysis cell (to avoid bubble entrapment within the complex 3D structure).

As an example, the added value of a numerical simulation for a better understanding of the electrolyte flux distribution within an empty cell (e.g. without 3D structure) is shown in Figure 2. The velocity field of the electrolyte (in m/s) was simulated on the OpenFOAM software. Note that the geometry of the cell corresponds to the one of the pilot electrolyser used at UCLouvain (see Figure 3).

IMMC main research direction(s):
Computational science
Fluid mechanics
Chemical engineering

Keywords:
computing
electrochemical engineering
finite elements
finite volumes
fluid structure interaction
hydrogen production
mesh generation
numerical simulation, experimental models
two-phase flows

Research group(s): IMAP