One-step process to make diesel from CO2

CHEMICAL ENGINEERS at the Ulsan National Institute of Science and Technology (UNIST) have developed a new, one-step process to turn CO₂ directly into diesel.

Jae Sung Lee, a professor of energy and chemical engineering at UNIST, led the research to develop the process, which uses a catalyst made from a mineral called delafossite. Existing processes to convert CO₂ into hydrocarbons generally require more than one step, for example, a process developed by Audi has two stages, the first a reverse water gas shift (RWGS) reaction to convert CO₂ into CO, followed by Fischer Tropsch synthesis. The process developed by Lee and his team creates long-chain hydrocarbons suitable for diesel fuels.

Delafossite, CuFeO₂, is low-cost and abundant. The researchers reduce the delafossite in a carburisation reaction (heating it with a carbon source) to produce Hägg iron carbide, the active form. The CO₂ is reacted with H₂, produced from a solar hydrogen plant, at a ratio of 1:3, at 300?C with pressure at 10 bar, in the presence of the catalyst. The reaction produces around 65% hydrocarbons with at least a 5C chain length, which could be used directly as fuel.

“We believe the new catalyst breaks through the limitation of CO₂-based Fischer-Tropsch synthesis and will open the avenue for new opportunities for recycling CO₂ into valuable fuels and chemicals,” said Lee.

Applied Catalysis B: Environmental DOI: 10/btd9