Solid Oxide Electrolysis Cell-Based Syngas Production and Tailoring: A Comparative Assessment of Coelectrolysis, Separate Steam, CO2 Electrolysis, and Steam Electrolysis

Solid oxide electrolysis cell (SOC) systems offer a promising solution for generating green syngas crucial in decarbonizing challenging sectors like chemicals, steel, and transport. In this steady-state system modeling study, three distinct system concepts for SOC-based tailored syngas production from steam and CO2 have been investigated. The system models are implemented within ASPEN, and an experimentally validated SOC reactor model has been utilized. At the system level, a parametric analysis is performed by varying inlet composition, fuel utilization, SOC operating pressure, and maximum oxygen content in the SOC exhaust. The results are used to identify system design challenges that differ for the three routes and the most preferable system based on energy efficiency, system complexity, and feasible syngas compositions. System configurations involving purely electrochemical conversion of steam and CO2 are found to have 2–7% higher system efficiencies. Pressurized electrolysis leads to 5–8% lower system efficiencies when taking into account the maximum O2 concentration constraint for the exhaust air.