Scientists at the US Department of Energy’s Idaho National Laboratory (INL) have developed a technology that could finally make it economically feasible for coal plants to curb their carbon emissions.
The solution sees the transformation of captured carbon dioxide into syngas, which can then be used to make chemicals or fuel. Traditionally, carbon dioxide emissions must be exposed to high temperatures and pressures in order to be reduced for reuse, but the process developed by the scientists at INL, which involves the use of specially formulated liquid materials, eliminates this requirement by enhancing the solubility of CO2 and, according to Phys.org, allows “the carbon capture medium to be directly introduced into a cell for electrochemical conversion to syngas.”
“For the first time it was demonstrated that syngas can be directly produced from captured CO2 — eliminating the requirement of downstream separations,” researchers explained in the journal Green Chemistry.
Switchable polarity solvents are at the core of this new process, which prompt a change in polarity once exposed to a chemical agent. It is this very characteristic that allows scientists to pick and choose which molecules will dissolve in the solvent.
In the case of turning CO2 into syngas, hydrogen ions react with CO2 in the form of bicarbonate, thereby releasing CO2 for electrochemical reduction and the formulation of syngas. When the CO2 is released, the switchable polarity solvents reverts back to a water-insoluble form. It is this final process that allows the carbon capture media to be recovered and reused. Scientists found that the process worked best at 25 degrees C and 40 psi.
If adopted on a wide scale, INL’s technology could significantly help coal plants drive down their emissions. In addition to helping plants safeguard themselves against the financial burden of climate legislation and create an additional source of revenue, the technology could eliminate a major source of CO2 emissions globally.
The research was supported by funding from the Laboratory Directed Research and Development in 2017. INL is now seeking a patent for the process.
“It integrates two areas that have been on parallel tracks: carbon capture and sequestration (CCS) and CO2 utilization,” said Luis Diaz Aldana, the experiment’s principal researcher. “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.”