Direct air capture multiscale modelling: From capture material optimization to process simulations

A potential to decarbonize atmosphere, while simultaneously providing a feedstock for functional industrial applications, induces a strong economic incentive for direct air capture (DAC). However, DAC systems, developed to date, are energy, resource, and cost prohibitive. Measurement-complementing multiscale modelling has proven to be of a large visible value for the sorbent rapid screening from a vast scientific collection of prospective selected candidates, machine learning (ML) integration, and for the process design engineering with a characteristic low penalty for CO2 regeneration and optimal uptake rates. The review provides an extensive evaluation of recent advances in multiscale modelling of DAC research. It introduces the theoretical physical descriptions of DAC, presents atom scale structuring, and brings together the state of the art of this, until now, poorly-researched analysis topic. Reviewed (CO2 mass) transfer works span from the ab initio density functional theory (DFT) calculation relationships to mesoscale Monte Carlo, molecular dynamics simulations and micro-kinetics, adsorption/desorption, and lastly, most commonly-investigated specific macroscale concept. The modelled DAC processes properties reported in the literature have been compared, which allowed us to identify the most effective sorbents. Amine functionalized metal-organic frameworks exhibit low energy requirements, the lowest reported was 1000 kWh tCO(2)(-1), while the lowest published cost was 60 $ tCO(2)(-1). Recently, there are progressively emerging promising new entrants into the DAC field, providing climate-neutral feedstock for commercial processes. The market demand for CO2 is expected to exponentially rise up to 6.1 Gt in 2050, while the cost of implementing DAC technologies is predicted to be reduced under 125 $ tCO(2)(-1) in the year 2030. Further modelling research activities in CO2 (sorption) bed form phenomena could not only break the barriers of current renewable technologies, but also couple the CO2 reactions with the sequestration, reactors, and neutralization of harmful environmental pollutants, monoxide, NOx, SOx, etc. DAC could be ultimately coupled with electrolysis (hydrogen), producing e-fuels.