One Step Process Converts CO2 And Water into Liquid Fuel

University of Texas at Arlington (UTA) chemists and engineers have proven up a process that concentrates light, heat and high pressures to drive a one-step conversion of carbon dioxide and water directly into usable liquid hydrocarbon fuels.

This simple and inexpensive new sustainable fuels technology could be fed from removing carbon dioxide from the atmosphere to make fuel. The process also reverts oxygen back into the system as a byproduct of the reaction, with a clear positive environmental impact, the researchers said.

Frederick MacDonnell, UTA interim chair of chemistry and biochemistry and co-principal investigator of the project said, “Our process also has an important advantage over battery or gaseous-hydrogen powered vehicle technologies as many of the hydrocarbon products from our reaction are exactly what we use in cars, trucks and planes, so there would be no need to change the current fuel distribution system.”

The research results have been published in the Proceedings of the National Academy of Sciences titled “Solar Photothermochemical Alkane Reverse Combustion”. In the paper the researchers demonstrate that the one-step conversion of carbon dioxide and water into liquid hydrocarbons and oxygen can be achieved in a photothermochemical flow reactor operating at 180º to 200º C and pressures up to 6 atmospheres.

Brian Dennis, UTA professor of mechanical and aerospace engineering and co-principal investigator of the project said, “We are the first to use both light and heat to synthesize liquid hydrocarbons in a single stage reactor from carbon dioxide and water. Concentrated light drives the photochemical reaction, which generates high-energy intermediates and heat to drive thermochemical carbon-chain-forming reactions, thus producing hydrocarbons in a single-step process.”

UTA vice president for research Duane Dimos commended the researchers on their success saying, “Discovering a one-step process to generate renewable hydrocarbon fuels from carbon dioxide and water is a huge achievement. This work strengthens UTA’s reputation as a leading research institution in the area of Global Environmental Impact, as laid out in our Strategic Plan 2020.”

The hybrid photochemical and thermochemical catalyst used for the experiment was based on titanium dioxide, a white powder that cannot absorb the entire visible light spectrum.

MacDonnell said, “Our next step is to develop a photo-catalyst better matched to the solar spectrum. Then we could more effectively use the entire spectrum of incident light to work towards the overall goal of a sustainable solar liquid fuel.”

The authors envision using parabolic mirrors to concentrate sunlight on the catalyst bed, providing both heat and photo-excitation for the reaction. Excess heat could even be used to drive related operations for a solar fuels facility, including product separations and water purification.

MacDonnell and Dennis’ investigations are also focused on converting natural gas for use as high-grade diesel and jet fuel. The researchers developed the gas-to-liquid technology in collaboration with an industrial partner in UTA’s Center for Renewable Energy and Science Technology, or CREST, lab, and are now working to commercialize the process.

If, and so far its a tough if, CO2 can be harvested economically out of the atmosphere this technology will be welcome. But on the other hand, there are a lot of CO2 emitters, many with an blown business model thanks to government intrusion that might find this technology a true game changer as their CO2 is readily available.

The Texas team might want to re evaluate the prospective users, the technology might take off real quick in some existing industries.