Model-Based\nEnergy and Cost Analysis of Direct Air\nCapture Using ePTFE-Based Laminate-Structured Gas–Solid Contactors

Carbon dioxide removal\n(CDR) technologies will play a significant\nrole in limiting global warming if implemented on a large scale. Direct\nair capture (DAC) is a scalable approach for removing atmospheric\ncarbon, yet the true scope of its scalability remains unclear due\nto the early stage of technology development and high first plant\ncosts. This study provides groundwork for understanding the technoeconomic\ntrade-offs in developing DAC systems using laminate-structured gas–solid\ncontactors, encompassing the analysis of both contactor and process\ndesign spaces. The robust mass transfer and process models outlined\nin this study provide tools for evaluating DAC processes and designing\nDAC plants based on cost and energy analysis. First, the key contactor\ngeometrical parameters are identified to understand the CO<sub>2</sub> productivity–energy demand trade-offs, where geometries yielding\nhigher mass transfer rates can achieve higher CO<sub>2</sub> productivities\nat the expense of energy consumption by fans and steam use. Next,\na detailed process parametric study is conducted for DAC systems coupled\nwith steam-assisted temperature-vacuum swing adsorption (S-TVSA) to\nvisualize the trade-offs in the multidimensional design space. The\nmain cost driver dramatically changes over different process conditions,\nbut the operating cost prevailed on the Pareto front, with potential\nto operate as low as 150 $/tonne-CO<sub>2</sub> (within the cost range\nof 148–504 $/tonne-CO<sub>2</sub> in this study where the DAC\nsystem is coupled with industrial facilities for steam production).