The increased concentration of CO2 in the atmosphere contributes significantly to global warming. To recapture it, we are developing a direct air capture system based on alkali carbonates as solid sorbents to purify the ambient air. There is a little less than one gram of CO2 in a cubic meter of ambient air, so we need to move large air streams and also process a lot of sorbent material. This raises many challenges, such as avoiding dust emissions, planning for upscaling from the beginning, and selecting a durable and widely available combination of materials.

The CO2 is separated from the absorbent in a special regeneration unit. After separation, the CO2 is frozen into dry ice for storage, while the absorbent is regenerated to be reused in the air contactor. We aim for high energy efficiency and full automation of the entire process.

For the storage of CO2, we are developing special structures that can hold dry ice at low temperatures. The solid state of CO2 is suitable for storing large quantities under controlled and safe conditions, with efficiency increasing with size. Designing these structures in a resource-efficient and economical way while ensuring a high degree of intrinsic safety is a special challenge that has never been faced before.