Cleaner energyNew technique could help coal plants reduce greenhouse gas emissions

Published 20 December 2017

Carbon capture could help the nation’s coal plants reduce greenhouse gas emissions, yet economic challenges are part of the reason the technology isn’t widely used today. That could change if power plants could turn captured carbon into a usable product.

Carbon capture could help the nation’s coal plants reduce greenhouse gas emissions, yet economic challenges are part of the reason the technology isn’t widely used today. That could change if power plants could turn captured carbon into a usable product.

Scientists at the U.S. Department of Energy’s Idaho National Laboratory have developed an efficient process for turning captured carbon dioxide into syngas, a mixture of H2 and CO that can be used to make fuels and chemicals. The team has published the results in Green Chemistry, a publication of the Royal Society of Chemistry.

Traditional approaches for reusing the carbon from CO2 involve a reduction step that requires high temperatures and pressures. At lower pressures, the CO2 doesn’t stay dissolved in water long enough to be useful. LNL says that the process developed at INL addresses this challenge by using specialized liquid materials that make the CO2 more soluble and allow the carbon capture medium to be directly introduced into a cell for electrochemical conversion to syngas. In short, it provides industrially relevant conversion rates, unlike other systems.

When syngas can be produced from captured CO2 at significant current densities, it boosts the process chances for industrial application. Unlike other processes that require high temperatures and high pressures, the SPS-based process showed best results at 25 degrees C and 40 psi.

INL’s team has filed a provisional patent and is discussing the approach with a Boston area company involved in electrochemical technology research and development, Lister said.

“It integrates two areas that have been on parallel tracks: carbon capture and sequestration (CCS) and CO2 utilization,” said Diaz Aldana. “The problem with CCS has been its economic feasibility. If you can get some extra value out of the CO2 you are capturing, it’s a different story.”

Idaho National Laboratory is one of the U.S. Department of Energy’s national laboratories. The laboratory performs work in each of DOE’s strategic goal areas: energy, national security, science and environment. INL is the nation’s leading center for nuclear energy research and development. Day-to-day management and operation of the laboratory is the responsibility of Battelle Energy Alliance.

— Read more in Luis A. Diaz et al., “Electrochemical production of syngas from CO2 captured in switchable polarity solvents,” Green Chemistry (19 December 2017) (doi: org/10.1039/C7GC02295F)