German researchers develop process that produces carbon out of air

The system can remove 4.4 lbs of CO2 in one day, converting them into 1.1 lbs of solid carbon.
Jijo Malayil
The new NECOC facility at KIT
The new NECOC facility at KIT

Markus Breig, KIT 

Researchers at Karlsruher Institute for Technology in Germany have developed an innovative process that produces carbon out of the CO2 present in the atmosphere.

The project's first-phase installation can remove 0.001 tonnes (two kilograms) of CO2 from the ambient air in one day, converting them into 0.5 kilograms of solid carbon.

The research project, named NECOC (Negative Carbon Dioxide to Carbon), was conceived in association with INERATEC and Climeworks. The efforts are part of the goal to make Germany carbon neutral, requiring it to "close carbon cycles in its industries as soon as possible to get there," said a press release

Meeting targets

The Intergovernmental Panel on Climate Change (IPCC) has indicated the need to remove and permanently store the already present CO2 in the atmosphere to meet the 1.5-degree target set for a rise in temperature by 2030. 

“We have to find completely new technological solutions if we want to keep up industrial production,” says Dr. Benjamin Dietrich of the KIT Institute of Thermal Process Engineering (TVT). The potential of industrial supply of carbon produced is suggested, which is required in the "production of batteries, building materials, colors, and in the agricultural sector. Carbon is largely produced from fossil fuel sources around the world. 

“If this carbon remains permanently bound, we successfully combine negative emission with a component of the post-fossil resource supply as part of a future carbon management strategy," said Dietrich. The team says this would double contribute to a sustainable future.

How the system captures CO2

The process includes three steps - an absorber to separate the CO2 from the ambient air constitutes the first step of the cycle. The CO2 is moved to a microstructured reactor in the second phase, reacting with the hydrogen from a connected electrolyzer.

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The reaction results in components - carbon and oxygen, forming new bonds, and the CO2 is converted into methane and water. While the water flows back to the electrolyzer, the methane, including the carbon, ends up in a reactor with liquid tin. 

In the final step, "a pyrolysis reaction splits the methane molecules, creating hydrogen, which can be returned to split CO2." The remaining carbon, which floats on the tin as micro granules can be removed mechanically.

The team was able to alter the parameters like temperature level to produce different carbon modifications like graphite, carbon black, or even graphene.

The second phase will help scale the process

Opportunities to scale up and optimize the process for expansion will be the primary objective of phase two of the project. 

“We are planning to make the procedure more energy-efficient by improving the energy recovery from the process heat,” said project director Dr. Leonid Stoppel from the Karlsruhe Liquid Metal Laboratory. 

The team is also looking into integrating high-temperature heat storage and direct solar heating in the process.