Experimental scale-up of tandem reaction zone dielectric barrier discharge plasma reactors for CO₂ hydrogenation: effects on electrical consumption and absolute product yield

Utilization of single-carbon gases, CO2 and CH₄, has grown recently focused on converting to C₂₊ chemicals/fuels. Thermodynamic stability requires elevated pressures and/or temperatures for efficient conversion with thermal catalysis, resulting in high operating expense at industrial scale. Atmospheric-pressure plasma can achieve conversion without external heating or pressurization via high-energy electrons. Plasma acts synergistically with catalysts to drive reactions to desired products, called plasma catalysis. Plasma systems must be scaled-up to become usable at commercial scale, but there is limited literature exploring effects on reaction chemistry and electrical consumption. We scaled a DBD packed-bed reactor with Fe-Co catalyst and TiO₂ support in a tandem configuration for CO₂ hydrogenation by: (1) increasing reactor length with gas flow; (2) parallel reactors. A 150% length increase resulted in 20% increased plasma power, increasing C₂₊ yield by over 100%, signaling promise for scaling. Parallel reactors suffered inconsistent product distribution, doubled power consumption for 2 reactors, and exceeded power supply capabilities for 3, indicating necessity of designing power supplies to match dynamic reactor loads.