Abstract
•The first 2D combined CH4-assisted SOEC and F-T synthesis model is developed.•A novel strategy towards low-carbon fuel generation is proposed.•Parametric studies are conducted with performance determining factors discussed.•The distribution of generated carbon-contained fuels (from C1 to C5+) is studied.
CH4-assisted solid oxide electrolyzer cells (SOECs) can co-electrolyze H2O and CO2 effectively for simultaneous energy storage and CO2 utilization. Compared with conventional SOECs, CH4-assisted SOECs consume less electricity because CH4 in the anode provides part of the energy for electrolysis. As syngas (CO and H2 mixture) is generated from the co-electrolysis process, it is necessary to study its utilization through the subsequent processes, such as Fischer-Tropsch (F-T) synthesis to produce more value-added products. An F-T reactor can convert syngas into hydrocarbons, and thus it is very suitable for the utilization of syngas. In this paper, the combined CH4-assisted SOEC and F-T synthesis system is numerically studied. Validated 2D models for CH4-assisted SOEC and F-T processes are adopted for parametric studies. It is found that the cathode inlet H2O/CO2 ratio in the SOEC significantly affects the production components through the F-T process. Other operating parameters such as the operating temperature and applied voltage of the SOEC are found to greatly affect the productions of the system. This model is important for understanding and design optimization of the combined fuel-assisted SOEC and F-T synthesis system to achieve economical hydrocarbon generation.