(173e) Scale-up of Electrochemical Carbon Dioxide Separation Using Membrane Electrode Assemblies
AIChE Annual Meeting
2017
2017 Annual Meeting
Separations Division
Rapid Fire Session: TED-Sep Separations Division
Monday, October 30, 2017 - 1:10pm to 1:16pm
Scale-up of multi-cell membrane electrode assembly (MEA) systems require reproducible fabrication of reliable electrodes and membrane materials. Optimization of electrode support and catalyst microstructures ensures a high rate of CO2 separation through the anion exchange membrane. Separation of CO2 from a 5â7 mol% CO2, high-humidity gas mixture, representative of an exhaled breath, was demonstrated by a sub-scale system. Screen-printed Pt and IrO2 electrodes were fabricated and evaluated as single MEAs to measure baseline CO2 removal rates and electrochemical behavior. Catalyst microstructures were characterized using scanning electron microscope (SEM) imaging. Electrode mass and charge transfer resistances were quantified using electrochemical impedance spectroscopy (EIS). The electrode efficiency and CO2 flux were measured over a range of equivalent full-scale breathing flow rates (40 L/minâ120 L/min) for 3, 7, 11, and 22 cell stacks at variable current densities. The multi-cell system displayed performance linearity and uniformity with increasing number of cells. For a full-scale flow rate of 80 L/min, the multi-cell system achieved a CO2 flux of 1.57 L/m2·min with an electrode efficiency of 75%. Flow field design and cell hydrodynamics were addressed for scaleâup of the electrochemical system.