According to Prometheus’ investing materials, the process is divided into four main stages.
In the first stage, art fans draw in the air and blow it through a mixture of water and other compounds, which McGinnis says may contain sodium carbonate. It then reacts easily with carbon dioxide molecules in the air, transferring most of the carbonate to bicarbonate.
The resulting solution moves into a cell-like cell with a membrane in the middle and electrodes at both ends, which use electricity to spark a series of chemical reactions that produce complex alcohols. It is equipped with a catalyst based on technology licensed from the Oak Ridge National Laboratory. In an earlier statement, the lab said it had created a catalyst made from tiny carbon spikes embedded in copper nanoparticles. When a voltage is applied, it converts carbon dioxide dissolved in water to ethanol “with a yield of 63%.”
The carbon nanotube membranes of Prometheus act in the third stage, separating the alcohols from the water.
And in a final step, various catalysts are used to combine the alcohols and convert them into synthetic petrol, diesel or jet fuel. In 2020, Prometheus licensed a separate technology from Oak Ridge Lab that could be used to make jet fuel from ethanol, through a multistep process that relies on a novel yet indeterminate catalyst.
The overall process is quite different from other companies that are converting captured carbon into fuel. As McGuinness explains in a Joule commentary, Prometheus systems can operate at ideal atmospheric pressure and at room temperature. The technology avoids the heat energy required to produce concentrated carbon dioxide as well as the capital cost of an electrolyzer dedicated to hydrogen production. Instead, the company claims, it can synthesize alcohols directly from water-dissolved carbon dioxide and then convert them into ideal fuels.
If they really figured out how to do it, it could lead to “significant energy and cost savings,” said Evan David Sherwin, a postdoctoral researcher at Stanford who created the environmental science and technology study.
The last slides of investor content show a Prometheus-branded fuel station, where a red neon “Zero Net Carbon” sign advertises gas at $ 3.50 per gallon and diesel at $ 3.75, much lower than current US prices.