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Figure 2 Variability of generic CO 2 sensors (left) compared with stability of Vaisala sensors (right)
and harsh conditions. Measuring inline with automatic temperature and pressure compensation, the range of the MGP241 extends from 0-100 vol% CO 2 and also employs Carbocap technology for long-term stability. The MGP241 was found to be ideal for measurements after adsorption. Vaisala worked closely with Octavia to understand their DAC process in depth, to define the demanding measurement requirements, and to deliver a tailored CO₂ measurement solution that supports its future growth and contributes to the broader advancement of African climate innovation. Octavia Carbon’s DAC process There are three main phases in the process: adsorption, desorption, and liquefaction/ injection. Each phase requires energy, but with Kenya’s easy access to renewable geothermal energy, Octavia’s processes are low-cost and carbon-negative. In the first phase, ambient air (containing ~430 ppm CO 2 ) is pulled into the DAC machine, where it passes through a filter containing chemical sorbents. These chemicals selectively bind with CO 2 , effectively removing it from the air, until the filter material becomes fully saturated with CO 2 . The sorbent is a proven amine-based chemical supported in a wash-coated monolith. This formulation provides the performance, stability, and regeneration characteristics required for reliable DAC operation. However, sorbent development is an ongoing focus of Octavia’s R&D efforts. The team continuously evaluates
new materials and formulations with the aim of improving adsorption capacity, regeneration energy efficiency, mechanical robustness, and overall lifetime. Promising candidates are first tested in laboratory systems and then validated in Technology Readiness Level (TRL) 4-6 pilot machines under representative operating conditions. Materials that demonstrate strong performance and durability are subsequently upscaled and deployed in the plant. This iterative approach ensures that while a stable, production-ready sorbent is maintained, the team consistently strives for improvements in performance and cost efficiency over time. In the desorption phase, indirect heat under vacuum is applied to the filter material, causing it to release the concentrated CO 2 , which is extracted. This process regenerates the filters for reuse. In the final stage, the captured CO2 is compressed and cooled, which causes it to liquefy so that it can then be transported to secure geological sites where it is injected deep underground into appropriate rock formations. Under these conditions, the CO 2 gradually mineralises through a process known as carbonation and becomes a permanent part of the rock. Importantly, Octavia’s DAC process is completely modular and therefore scalable, enabling the company to set ambitious growth targets. Its first DAC plant (Project Hummingbird) (see Figure 3 ) was initially developed as a pilot to validate the technology, operating assumptions, and delivery model, but it is now being scaled through a phased
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