Direct air capture (DAC) is one of the technologies being developed to help achieve carbon neutrality by reducing carbon dioxide (CO2) concentration in the atmosphere, which will help mitigate the negative consequences of climate change. Currently, most commercially available and proposed CO2 capture systems use chemical solvents in a gas-liquid exchange column to scrub or separate the CO2 gas from a mixed gas stream. Given the release rate of CO2 in the environment, this established method that is designed for point-source capture is not sufficient and development of more efficient processes such as DAC has become critical. State of the art DAC technology uses a composite material made of active amine-based adsorbent material supported by an inert material. To further intensify the process and reduce the cost of the technology, an inert support-free adsorbent would be desired.
LLNL researchers have developed a self-supporting structural material that promises more efficient carbon capture specifically from air, but generally from all CO2 containing gas sources. The material is produced with a liquid high-amine-content precursor polymer that is functionalized by adding on polymerizable end groups. Crosslinking of the functionalized macromonomers result in a self-supporting network polymer. The mechanical, chemical, and physical properties of the material are improved with the introduction of some co-monomers. Additionally, to increase porosity, inclusion of leachable porogens that are removed after polymerization.
The final material thus contains a high density of amine sites and a high degree of porosity in order to allow rapid uptake of CO2. It is also reversible, allowing the CO2 to be released and subsequently contained. The structure can be fabricated as a free-standing cloth in a roll-to-roll process, or 3D printed via stereolithography and the like to fabricate packings or monoliths (e.g. straight channel monoliths, log pile structures, gyroids, triply periodic minimal surface (TPMS) structures, etc.).
- At least doubles of the swing capacity, the key performance metric for carbon capture methods
- Can capture CO2 from a variety of gas sources, including directly from air (DAC)
- Can directly replace current DAC materials for increased efficiency for the same air volumes and energy cost
- Reduces capital costs by reducing adsorber volume
- Decrease the amount of energy required for regeneration
- Reduces the amount of capital needed by increasing CO2 throughput
- Can withstand high air velocities while minimizing pressure drop across the material
- Minimizes loss of material due to attrition
- Direct air capture of CO2
- Point source CO2 capture