Research progress of typical process analysis and techno-economic research on direct air capture of carbon dioxide

In order to promote social development, green transformation and achieve the goal of carbon peak and carbon neutralization, direct air capture (DAC), as a technology that can achieve net zero carbon emissions, has attracted more and more attention. DAC technology focuses on the capture and recovery of CO₂ from distributed sources such as atmosphere and vehicles, which can effectively reduce the atmospheric CO₂ concentration. At present, the challenge of DAC technology development mainly lies in the high cost of equipment and operation.Therefore, it is described from three aspects: DAC process overview, key process modules and technical and economic analysis. The process flow and adsorption materials of two DAC technologies based on alkaline solution and solid adsorbent are emphatically introduced, and the key modules such as power / heat supply, CO₂ absorption/desorption, CO₂ compression storage / transportation are summarized. The energy consumption and economic cost of the two DAC technologies are compared.It is found that the energy consumption per ton of CO₂ capture of DAC technology based on alkaline solution absorption and solid adsorbent absorption is 2 118-2 790 kW·h and 1 400-2 777 kW·h respectively, and the cost per ton of CO₂ capture is ＄200-600 and ＄100-400 respectively. In general, DAC technology based on solid absorption has good economic benefits, low capture cost and great application potential. In the future, further research should be carried out from the three aspects of adsorption material performance improvement, key core process strengthening and system energy integration optimization, which is expected to further reduce the cost of DAC technology, thus providing important technical support for carbon peak and carbon neutralization.