LOUISVILLE, Ky. (KT) - Researchers at the University of Louisville’s Conn Center for Renewable Energy Research and the Chemistry Department are using a Department of Energy grant to convert the “flue gas” version of the greenhouse gas carbon dioxide, or CO2, into valuable products.
According to UofL, Earth depends on balanced levels of greenhouse gases for our warm climate, averaging 59oF, to sustain plant and animal life. However, since the Industrial Revolution, burning fossil fuels for energy has resulted in the excessive accumulation of atmospheric gases such as CO2, raising the temperature of the planet.
Greenhouse gas levels are now at the highest ever recorded and continue to rise as worldwide energy use is projected to double in the next 10 years.
Flue gas is the smoky exhaust from a furnace, boiler or generator and, on a larger scale, the gas that results from combustion at power plants. Approximately one-third of U.S. greenhouse gas emissions are attributable to the flue gas resulting from electricity generation by utilities.
While most research into carbon dioxide reduction has relied on pure gas, CO2 is more dilute in flue gas at typically less than 20%. The UofL project will pursue the development of a stable and efficient method to convert the CO2 directly from a power plant exhaust stream, which would aid in making the overall process more cost-effective.
Flue gas contaminants can degrade the performance of an electrolysis reactor, making the direct electrochemical conversion of flue gas CO2 a challenging prospect. The UofL team is working on novel molecular catalysts to guide the selectivity of the reaction within a new high-performance reactor designed for use with both water and organic solvent.
The major challenge of utilizing flue gas CO2 to produce carbon-based chemicals is to create technology that is efficient, economical and achievable at a commercial scale. Meeting these three criteria would provide an economic incentive for the industry by adding value to their waste instead of emitting it into the atmosphere.
Processing these power plant emissions will convert CO2 to useful products, including those where the single carbon atoms in CO2 are combined to form larger compounds with two to four carbon atoms. Such products include formic acid, ethanol and methyl formate, all of which are currently produced using fossil fuels.
This research is being funded by a $1.25 million two-year grant, allowing the recruitment of several graduate students and postdoctoral scholars, and will include research opportunities for undergraduate students as well.
This effort will pursue a high-performance reactor design capable of meeting the metrics necessary for a commercially viable process. This includes achieving much higher operating current densities, similar to water-based electrolyzers, than typical laboratory measurements and very high selectivity (~90%) for the desired chemical products.
“Electrochemical reduction of CO2 allows for renewable energy-driven production of chemicals and fuels in a distributed and modular fashion,” said Conn Center Director Mahendra Sunkara. “Conn Center is looking towards the development of a CO2 electrolyzer in the next five years.”