Syngas production by solid oxide electrolysis cells with flue gas feedstock

• Main Author: Pang, Kang Wei
• Other Authors: Chan Siew Hwa
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/71908
• Institution: Nanyang Technological University

Large quantities of green-house gas emissions (CO2 and H2O) produced from fossil fuel combustion are creating serious threats to the mankind. Hence in recent years, low-carbon clean energy technologies are becoming increasingly attractive. High temperature solid oxide electrolysis cell (SOEC) coupled with renewable energy has been regarded as a promising technology to achieve low-carbon economy and future. Solid Oxide electrolysis cells comprised of YSZ electrolyte, LSCM-GDC fuel electrode, and LSCF-GDC air electrode, used for syngas production with flue gas feedstock will be analyzed on. Main objective is also to develop a solid oxide electrolysis cell system for an efficient syngas production. To evaluate the electrochemical properties of the electrolysis cells, we have also conducted testing to obtain their I-V relationship and impedance spectroscopy. This project will also involve numerous experiments to gain deeper insights with how varying variables such as steam concentration, operating temperature, and material of electrodes can optimize the electrolysis efficiency and performance. Results have also shown that when we undergo water electrolysis and co-electrolysis of H2O and CO2, the cell has demonstrated much better performance at a high operating temperature. During water electrolysis process, increasing steam concentration may also increase cell performance. It is also worth noting that when we replace H2 with N2 as a balance of the gas feedstock, even though cell performance decreases at low cell voltage, similar current densities will be achieved at high cell voltages with nitrogen balanced gas feedstock (simulated flue gas), which indicates that LSCM electrode is indeed promising for the co-electrolysis of flue gas which contains no H2. Moreover, we have also conducted an experiment whereby impedance spectra under electrolysis bias were measured, and findings have shown that electrolyte resistance is not affected by the applied bias, but the electro-activity of the electrodes was enhanced.