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Catch-and-Consume: Recycling Carbon Emissions

PNNL chemist uses advanced solvents to capture carbon dioxide and convert it to fuel

October 2015
Catch-and-Consume: Recycling Carbon Emissions
PNNL's Dave Heldebrant was one of 44 researchers nationwide selected to receive research funding from DOE's Early Career Research Program. He is studying the molecular processes at work when carbon dioxide interacts with carbon-capture solvents. Here, Heldebrant is working to develop a solution that will capture carbon dioxide and sulfur.

Over the past decade, governments and utilities have been looking at how carbon capture technologies can reduce the emission of carbon dioxide, a greenhouse gas, into the atmosphere. Solvents, which can dissolve other substances—like carbon—are a key ingredient for carbon capture technologies.

Now, with a DOE Early Career Research Program award, PNNL researcher Dave Heldebrant is building off of earlier research progress with advanced solvent formulations to not only improve the efficiency of carbon dioxide capture, but also to convert it into useful fuels and chemicals.

Solving the Solvent Dilemma

As the name implies, traditional aqueous solvents contain water. The energy and higher temperatures required to remove the water taxes the efficiency of the overall system.

Promising new non-aqueous solvents, known as CO2-Binding Organic Liquids (CO2BOLs), don’t have to remove all the water, making them less energy intensive. However, as these advanced solvents work their magic on carbon, they also become increasingly viscous, turning from a thin, watery liquid into a thick goo, like toothpaste. This presented a different challenge: how to optimize the solvent while controlling viscosity.

With support from DOE's Office of Fossil Energy, Heldebrant used high-performance computing to simulate various solvent formulations. He compared the modeled results against the performance of actual synthesized chemicals, which verified the model predictions.

"Rather than taking an Edisonian or 'shotgun' approach to solvent synthesis and design, our systematic approach enables us to more efficiently weed out low-performing chemical and design combinations while, also learning how the optimal designs reduce viscosity." said Heldebrant.

Akin to using CAD software to design a building, close teamwork between computational and experimental chemists is accelerating the process of building the most effective solvents for carbon capture.

Through the Early Career award, Heldebrant is taking this approach even further. He will explore the molecular composition of the solvent, to see if it can be manipulated and combined with catalysts to promote both capture and conversion of carbon dioxide. This new 'catch-and-consume' concept holds the promise of creating energy-efficient, cost-effective, carbon-neutral energy generation, and reducing climate impacts.

PNNL Research Staff: Dave Heldebrant, Roger Rousseau, Vanda Glezakou, and Phillip Koech

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