NETL has initiated a four-year plan to develop a direct air capture (DAC) process that integrates expertise from the Lab’s extensive materials design, computational materials design, computation fluid dynamics, and process system design research portfolios to advance a cutting-edge technology that will remove carbon dioxide (CO₂) from the atmosphere.

DAC technologies use sorbents to pull CO₂ directly out of the air in contrast to point source capture processes that capture the greenhouse gas at power plants or industrial facilities. While point source capture will need to be effectively deployed as part of decarbonization efforts, DAC technology will be critical for counterbalancing hard-to-decarbonize sectors like agriculture, shipping, and aviation and for addressing legacy emissions.

While DAC is more challenging and more expensive than point source capture due to the low concentration of CO₂ in ambient air (only 400 parts per million), DAC has flexibility in terms of location. A DAC plant can be situated in any location that has a low-carbon energy source to power its operation and accessibility to a secure CO₂ storage resource or conversion opportunity.

“We are basing this process on an innovative sorbent developed at NETL. Our sorbent has high CO₂ uptake, fast kinetics and low-temperature regeneration that has demonstrated performance over hundreds of cycles,” said NETL’s Jan Steckel, Ph.D.   

Active DAC contactors use fans or blowers to move the air through the adsorbing materials during the adsorption step. Due to the energy cost of moving large volumes of air across the contactor material, it is important that the contactor geometry allow for quick sorption from the air without creating resistance to the air flow, which would increase the energy required. A unique advantage of the NETL sorbent is that it can be formed into many shapes, such as wet-spun fibers, flat sheets or electro-spun into porous fiber mats. The team at NETL is using a collaborative process to develop the sorbent into a low-cost contactor geometry that will lead to an efficient and low pressure-drop adsorption process.

“We are leveraging the Lab’s renowned open-source MFiX computational flow dynamics software to help design the absorber by running multiphase flow simulations,” Steckel said.

In a DAC process, CO₂ is collected from the sorbent during the regeneration step. Regeneration often relies on heating the sorbent to release the CO₂. Heating can unfortunately also lead to an undesirable degradation of the sorbent. Due to the formulation of NETL’s sorbent, regeneration can occur at comparatively low temperatures that are less likely to cause sorbent degradation.

Advanced modeling support is helping guide DAC technology development (including the design of the desorption process) through the development of rigorous, optimized property models. This will allow developers to understand the impact of regeneration protocols on the cost of the process, guiding development of the technology and reducing the risk associated with scale-up.

 

A major impact of the research in this portfolio is the development of a DAC demonstration module for testing in the DAC Center in EY26,” Steckel said. “This overarching impact is made possible by leveraging the extensive expertise and capabilities of different NETL teams, fostering an integrated, cooperative collaboration across the organization and incorporating early engagement with industry partners. This outcome will also incur the associated benefits of the multiscale modeling techniques associated with this project, which will be made available to sponsors and members of the community.”

The goal of the project is to license the materials and system to entities capable of scaling up the technology and performing commercial DAC operations.

NETL is a U.S. Department of Energy national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By leveraging its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.