Development of disk-type solid oxide electrolysis cell for CO2 reduction in an active carbon recycling energy system

摘要

CO2 recycling method characterized by the application of an Active Carbon Recycling Energy System (ACRES) to an iron-making process (iACRES) was studied. In this system, pure iron is produced from the reduction of iron oxide using regenerated CO by high temperature CO2 electrolysis with the use of a disk-type solid oxide electrolysis cell (SOEC) and powered by a high temperature gas-cooled reactor (HTGR) generating electricity and thermal energy. Thus, the focus of this research is to further improve the performance of disk-type SOEC by developing its structure and determining the most suitable electrode and electrolyte materials, and the appropriate fabrication method. In this present study, new cathode material such as Ni-SDC (SDC: samarium-doped ceria) was checked and tested for the SOEC. The electrochemical performance of the cells were evaluated at 800 ~ 900 °C by analyzing current-voltage characteristics, AC impedance spectra, and CO production data. Results showed CO production rates close to theoretical values corresponding to current density values observed. The performances of the SOEC samples were investigated for their potential use in iACRES, and the SOEC with Ni-SDC cathode showed the most enhanced electrochemical performance for iACRES. The results showed that iACRES is available for utilization of the high temperature heat at about 850 ~ 950 °C provided by HTGR in this system. This would mean utilization of CO2 emission-free thermal energy, and eventual expansion of use of nuclear energy beyond electrical power generation.