Abstract
Reduction of greenhouse gas emissions is an important environmental element to actively combat the global warming and climate change. In view of reducing the CO2 concentration from the atmosphere, the Direct Air Capture (DAC) options are promising technologies in delivering negative carbon emissions. The integration of renewable-powered DAC systems with the CO2 utilization technologies can deliver both negative carbon emissions as well as reduced energy and economic penalties of overall decarbonized processes. This work evaluates the innovative energy- and cost-efficient potassium - calcium looping cycle as promising direct air capture technology integrated with various CO2 catalytic transformations into basic chemicals / energy carriers (e.g., synthetic natural gas, methanol etc.). The integrated system will be powered by renewable energy (in terms of both heat and electricity requirements). The investigated DAC concept is set to capture 1 Mt/y CO2 with about 75 % carbon capture rate. Up to 50 % fraction of the captured CO2 stream will be then catalytically converted into the Synthetic Natural Gas (SNG) or methanol using the green hydrogen produced by the water electrolysis (using renewable power), the rest being sent to geological storage. As the results show, the integrated DAC - CO2 utilization system, powered by renewable energy, has promising performances in terms of delivering negative carbon emissions, promoting the utilization of renewables and reducing ancillary plant energy consumptions.