Experimental evaluation of triply periodic minimal surface packings for CO2 absorption in carbon capture processes

This study presents an experimental evaluation of 3D-printed triply periodic minimal surface (TPMS) structures as advanced structured packings for CO₂ absorption using aqueous potassium carbonate solutions. Seven TPMS geometries—Gyroid (75% and 85% porosity), Solid sheet Gyroid, Diamond, Primitive, I-Wrapped Package (I-WP), and Fischer–Koch S—were fabricated via stereolithography and tested in a laboratory-scale absorber column under systematically varied operating conditions, with all geometries except Gyroid 85% having a porosity of 75%. The effects of solvent concentration (10.0–30.0 wt.%), liquid flow rate (92–900 mL min⁻¹; 0.23–2.27 kg m⁻² s⁻¹), solvent temperature (303.0–323.0 K), gas flow rate (2.0–10.0 L min⁻¹; 0.005–0.025 kg m⁻² s⁻¹), and inlet CO₂ concentration (10.0–20.0 vol.%) on CO₂ capture efficiency were investigated.Across all conditions, TPMS packings outperformed the empty column, achieving up to ∼3 × higher CO₂ capture efficiency and enhanced solvent loading. The Gyroid structure with 85% porosity consistently delivered the highest performance, reaching a maximum CO₂ capture efficiency of ∼48% under optimal conditions. The unpacked column exhibited lower efficiency under identical conditions. Gyroid 75% and Fischer–Koch S formed the second performance tier, showing comparable efficiencies, followed by Diamond, Solid Gyroid, Primitive, and I-WP structures with progressively lower performance.Increasing liquid flow rate resulted in up to a threefold enhancement in capture efficiency, while increasing temperature led to approximately twofold variation, reflecting improved mass transfer and reaction kinetics. In contrast, increasing gas flow rate reduced efficiency due to shortened residence time. The results demonstrate that TPMS geometry and porosity critically influence gas–liquid contact, solvent utilization, and operational flexibility. This work provides quantitative insight into the design and optimization of TPMS-based packings for carbonate-based carbon capture systems and supports their application in CCS and BECCS processes.