How our tech works, Part 2: Regeneration

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DAC technology removes excess carbon from ambient air in two distinct steps: capture and regeneration. Today, DAC is a costly and energy-intensive task. It’s also a scalable pathway to remove atmospheric carbon at a gigaton scale, which is a necessary task if we’re to meet global climate goals.

As mentioned in Part 1, the Noya team set out on a quest to find the most efficient, low-cost regeneration process — a heads-down, in-the-lab journey that led us to activated-carbon monoliths.

Our electrifying use of these monoliths sets us up for a swift, cost-effective process that can scale quickly. Let’s dive in.

Capturing carbon with carbon

Step one: carbon capture. Fans move ambient air through a filter that contains Noya’s proprietary activated carbon-based sorbent. This sorbent reacts selectively with CO2 in the airstream, temporarily “capturing,” or adsorbing it. Once the sorbent is saturated with CO2, step two can begin.

Step two: regeneration. CO2 is desorbed, or released, from the saturated filter in a high-temp, low-pressure environment. This process provides a stream of pure CO2 that can then be sequestered and stored permanently in capped, underground reservoirs, turned into rock in porous underground deposits through a process called mineralization, or even used in products, including industrial materials such as concrete and plastic.

The regeneration process is the most energetically expensive step within most DAC systems. The need for constantly changing pressure and temperature typically calls for extremely high energy inputs, and also makes for a process susceptible to high energy losses.

Regeneration, but make it electrothermal

The energy-intensive needs of DAC is problematic. To achieve a rapid, sustainable, and just energy transition, available renewable energy must be used as efficiently and effectively as possible. 

So we set out on our quest to find the most efficient, low-cost regeneration process. And we did!

Noya uses an electrothermal regeneration approach. This means we apply electricity directly to the activated-carbon monoliths (you know, the ones we chose for their electrical conductivity) — a process known as Joule heating. This applied heat reverses the CO2 capture reaction and regenerates the sorbent back to its initial state so the capture process can begin anew. In other words, heating up the saturated filter desorbs, or more or less “shakes off” the captured CO2 molecules. The freed up CO2 molecules are then compressed for permanent storage.

This approach allows for rapid heating… 

… and also helps us to avoid the energy losses associated with typical regeneration processes. 

Other DAC approaches commonly heat a capture sorbent by conduction within a heat exchanger or convection via steam, air, or other gasses. This approach is inefficient due to the need for heating intermediary mediums before heat can be transferred to the sorbent. Energy losses occur, and the process can take as much as seven times longer than using a fully electric regeneration process.

Our electrothermal regeneration approach results in significantly lower energy use, and as such, enables us to remove atmospheric carbon at ultra-low costs.

A swift process for quick scaling

By bypassing the inefficiencies associated with other DAC systems, we’re able to regenerate quickly (our capture and regeneration cycles are about one hour long) and with minimal energy losses. This means that not only is our process cost-effective, but also that we can scale up fast to remove CO2 from the atmosphere on timescales that meaningfully address climate change.

An electrothermal regeneration process also makes for flexibility in where we choose to deploy our facilities. Unlike other DAC systems, Noya’s systems don’t need to be near a thermal energy or waste heat source. The fact that we don’t require site-specific sources of energy means we have the freedom to choose sites based on where we can have the highest community impact. Isn’t that electrifying? ⚡

Next up: the modular nature of our DAC approach, and how it allows us to optimize our capture process over time.