Exploring Tradeoffs in Syngas Production with Solid-Oxide Electrolysis via Multi-Objective Optimization

Syngas is an important intermediate with a wide range of applications. Recent efforts at Forschungszentrum Jülich focus on the electrolytic production of syngas from water and carbon dioxide through high-temperature solid oxide cell electrolysis cells (SOEC) for use in methanol synthesis in the context of the DryHy project. In this work, an ASPEN Plus model is developed and use to explore the trade-offs between different objectives in syngas production using solid oxide electrolysis cells. Two different system designs are investigated: a low and a high utilization design. Four key objectives related to syngas composition and SOEC system performance are considered: energy efficiency, stoichiometric number, carbon oxide ratio, and the inlet water-to-carbon dioxide ratio. The trade-offs between these objectives are analyzed to gain insights into the operation of SOEC systems in co-electrolysis mode. A comparison of the two designs reveals that the high utilization design consistently outperforms the low utilization design for the considered objectives. In addition, it is observed that a significant difference in the inlet water-to-carbon dioxide ratio required to achieve the stoichiometric number needed for methanol synthesis exists.