Every second, power plants burning fossil fuels release millions of pounds of carbon dioxide.
The most common approach for reducing these emissions is a process known as post-combustion absorption. In this process, the power-plant flue gas travels up an absorption column as a liquid solvent travels down. When the gas and solvent come into contact, the carbon dioxide in the flue gas is captured by the solvent, and it can then be separated by heating up the solvent in a regeneration process. The captured carbon dioxide is compressed and transported to a geological site where it is injected and stored deep underground. The regenerated solvent is recycled back into the absorption process.
The absorption column used in this process is filled with structured packing that serves to increase the surface area of contact between the gas and the solvent.
Stephen Bolton, an undergraduate student at the University of Delaware and a participant in the National Academy of Engineering (NAE) Grand Challenges Scholars Program, focused on the structured packing during a recent internship at Oak Ridge National Laboratory (ORNL). Bolton’s internship at ORNL was through the Higher Education Research Experiences (HERE) Program.
Under the mentorship of Dr. Costas Tsouris, a chemical engineer in the Applied Catalysis and Emissions Research Group at ORNL’s National Transportation Research Center, Bolton contributed to research that involves 3D printing the structured packing to make it more efficient.
As the reaction between the gas and solvent proceeds during post-combustion absorption, the solvent heats up, quickly rendering it ineffective, Bolton explained. With 3D-printed structured packings, however, a coolant (ethylene glycol) can be run down tiny channels in the structure, which serve to cool the solvent and improve its effectiveness. In this way, the structured packing also works as a heat exchanger. Bolton’s research consisted of observing the behavior of the 3D-printed structured packing elements and comparing their performance to commercial packing elements.
Through his internship at ORNL, Bolton gained new technical skills related to the design and use of absorption and distillation columns and learned the LabVIEW programming software. He also benefited from his interactions with research staff at the lab.
“Through discussions about research and laboratory tours, I’ve discovered entire topics of research that I didn’t know existed,” he said. “I’ve also come to understand what a career in research entails. Everyone has been incredibly helpful and eager to help me learn.”
Bolton is grateful for the chance to conduct research at ORNL and encourages others to explore similar opportunities.
“There is no better way to discover your interests and strengths than by doing your own meaningful research while surrounded by motivated and intelligent people,” he said.
The HERE program at ORNL is administered by the Oak Ridge Institute for Science and Education (ORISE) for the U.S. Department of Energy.