Effect of stack operating temperature on the Techno-Economic analysis of a Solid Oxide Electrolysis system
Effect of stack operating temperature on the Techno-Economic analysis of a Solid Oxide Electrolysis system
Effect of stack operating temperature on the Techno-Economic analysis of a Solid Oxide Electrolysis system
Solid Oxide Electrolysers (SOE) are thermodynamically the most efficient type of electrolysers out there due to their high operating temperature (800°C-1000°C). The electrolysis Membrane-Electrode Assemblies (MEA) consists of three distinct layers: a porous air electrode, a dense membrane electrolyte, and a porous fuel electrode. In the fuel electrode steam is converted into oxygen ions and hydrogen. The oxygen ions travel through the electrolyte to the air electrode, which converts them back in to oxygen. The three layers are ceramics or cermet materials which are generally quite expansive and consist of rare earth materials. Decreasing the amount of required materials can save quite some costs and critical raw material usage.
Recently some work was performed which investigated the optimum way of making the MEA in terms of costs, CO2 emissions and raw material usage. Different ways of making these MEAs were considered and the porous electrode layers are optimized at different temperatures. The results showed a variation with temperature in the porous electrode layers. At lower temperatures more materials were required compared to the higher temperatures in the optimal electrode structure.
The MEA is the smallest part of the full electrolysis system. The MEA is considered the through cut of the a full SOE cell. These cells are stacked on top of each other to create a stack. The stack together with the rest of the balance of plant components (heat exchangers, condensers, etc.) make up the full electrolysis system. The operating temperature of the system is quite important impactfull for the CAPEX and OPEX. Due to the high temperatures, uncommon steels, which are more expansive, are required which are resistive of the oxidative potential. Additionally, higher temperatures means more preheating of the gasses which enter the stack. Lowering these temperatures to ~600°C makes the SOE a more competitive technology as it matches well with most industrial processes.
In this master assignment the goal is to investigate how the operating temperature plays a role in the techno-economic analysis of the full electrolysis system. To perform this analysis a flow-sheet needs to be drawn up, and modelled. An already existing code exists which simulates the electrochemical performance of the MEA, which can be used as an idealized stack. In the end, the techno-economic analysis hopefully shows us how we can manufacture the MEA such, that lower temperatures are achievable and profitable.
If you are interested in some process engineering with a hint of electrochemistry? Send me an email and we can have a coffee where I can tell you a bit more about the assignment.
Contact info:
Daily supervisor:
Wisse Hersbach – w.m.hersbach@utwente.nl