Using natural carbonate minerals to capture and store carbon from the air
The Heirloom process utilises the reaction of atmospheric CO2 with reactive oxides produced from Earth-abundant carbonate minerals, followed by calcination of the carbonate to recover high purity CO2. The CO2 is then transported to a disposal site where it is injected underground, or utilised.
The concept does not involve fundamentally new science, but represents a novel implementation of these processes to carbon removal. CO2 is directly captured from the atmosphere and sequestered in the Earth, so this process is unambiguously removing CO2 and can be directly measured in real time.
The proposed process is designed to be simple and therefore seems feasible and robust for scale-up. The design of the process is still being developed, with key decisions being the configuration of the plant, as well as the final mix of sorbent material. The process is such that the material used to capture CO2 can be re-used once the carbon has been extracted from it. Given the requirements of this material we don't have any major concerns on the final sorbent mix selection. As the projects scale there are engineering challenges, but no showstoppers are apparent.
We expect to see the CO2 emissions from operating all of the sub-processes to be included in the CO2 accounting in future (cooling for water dropout during CO2 capture, energy to operate the calciner, etc.). The system is in an early-stage of development, so we expect increasing clarity on CO2 and cost reduction of the process as it scales.
The larger risk in the Heirloom process is the reliance on CO2 transportation and storage. As the process pulls CO2 from the air, it may be possible to operate the process near a storage site, eliminating the need for long-distance CO2 transportation.
With the above concerns being stated, we think the process represents one of the most exciting new developments in carbon removal. We believe the challenges are largely engineering oriented and solvable - in particular, the cement and other related industries have solved many similar challenges before.
Written in collaboration with Dr. Corey Myers and Dr. Martin Chan
N.B. CarbonPlan have not yet had the opportunity to assess the project