Optimization of a scaled-up electrochemical cell for CO2 conversion

This thesis presents the optimization of an electrochemical CO₂ reduction cell for producing CO rich syngas under continuous flow operation. The work integrates mechanical design improvements, fluid dynamics, electrochemical performance evaluation, and economic assessments to enhance the overall efficiency and stability of the system. Seven design iterations were explored, focusing on enhancing flow uniformity, minimizing pressure drop, and optimizing the material selection to support sustainable CO₂R processes. The final design (Design 7) combined spiral flow fields, and reinforced ribs to achieve uniform flow distribution and reduced pressure drop across the electrolyte chamber. Also, dual-depth inlet seats are considered for the gas chamber to use stainless steel current collector instead of cupper tape which has the risk of degradation. Mechanical analysis confirmed that the PTFE chamber and carbon paper GDE, used as key structural and electrochemical components, perform well within their mechanical limits, with the maximum stress for PTFE at 0.330 MPa and the GDE stress at 23.3 MPa, both safely below their yield strengths. Electrochemical simulations showed that the optimized design improves CO partial current density from 1.55 to 1.83 mA·cm⁻² while maintaining a consistent hydrogen evolution reaction (HER) rate. Faradaic efficiency for CO consistently exceeded 80%, with Design 7 achieving 82.4%. Energy analysis revealed that the specific electricity consumption for CO production remained stable at approximately 5.74 kWh/kg CO, with a corresponding cost of 1.659 €/kg CO. When considering total syngas production (CO + H₂), the specific energy consumption increased slightly, but the resulting cost remained competitive, with Design 7 showing a lower total cost than the original configuration. Thermal analysis demonstrated that the cooling requirements were minimal, with negligible impact on overall operational expenses. The study highlights the critical role of flow field optimization in improving electrochemical performance and reducing production costs. The final optimized design provides a scalable and reliable solution for future CO₂R systems, with applications in low carbon syngas production and sustainable energy storage.