Capturing Carbon Through Cleaner Combustion

July 20, 2015

When it comes to releasing carbon dioxide into the atmosphere, the combustion of fossil fuels is far and away the biggest offender. In fact, the Department of Energy estimates that the process creates approximately 30 billion tons of CO2 every year — approximately 40 percent of all carbon emissions. Given the current limitations in clean, renewable energy technology, such as solar power, and its relatively low implementation, the burning of fossil fuels remains our primary source of energy. If we can’t go without it for the immediate future, we need to do what we can to make the process cleaner. In Professor Jeongmin Ahn’s Combustion & Energy Research (COMER) Laboratory, Ryan Falkenstein-Smith and his fellow researchers are developing a material to facilitate the capture of carbon dioxide at fossil fuel-burning power plants before it can be released into the atmosphere. In traditional fossil fuel combustion, a chemical reaction takes place between fuel (oil, coal, or natural gas) and air (made up of primarily nitrogen and oxygen). This produces heat, light, and useful energy. Molecularly, we’re left with nitrogen, carbon dioxide, and water vapor. The material Falkenstein-Smith is developing uses a novel technique to remove nitrogen from the equation. By doing this, the combustion process requires less energy and is more efficient. Typically, removing nitrogen from air requires the use of an air separation unit. These tend to be energy-hungry devices—the amount of energy they eat up counters any energy savings gained by burning pure oxygen. In the COMER labs, researchers are trying to overcome this obstacle. Their material is a fabricated ceramic that acts as an ionic conductor. The material is molded into hollow fibres. Using a simple chemical gradient, it is able to move oxygen ions through its membrane, while blocking the nitrogen from the combustion process. The oxygen is fed through the hollow fibres along with the fuel. They ignite and after combustion, you’re left with carbon dioxide and water vapor, which can be frozen and buried, or even put to use, sometimes in something as common as carbonating soda. There is increasing pressure for industry to reduce carbon dioxide emissions from combustion processes. The fabrication, characterization and experimentation of this material is just one piece of solving that large puzzle, but eventually, it could have a big impact. Falkenstein-Smith is eager to see ideas like his implemented in the near future. He says, “In the COMER lab, I get to work on projects that could one day make a significant difference in the real world and that's the reason I wanted to become an engineer. I want to create something with value. I feel that I'm doing that with this research. Carbon capture is a hot topic right now and it will continue to develop. I imagine that technology like ours will be widespread in 10-20 years. It’s amazing to be a part of a team that is focusing on it so early on.”