Using concentrated solar energy to reverse combustion, a research team from Sandia National Laboratories is building a prototype device intended to chemically "reenergize" carbon dioxide into carbon monoxide using concentrated solar power. The carbon monoxide could then be used to make hydrogen or serve as a building block to synthesize a liquid combustible fuel, such as methanol or even gasoline, diesel and jet fuel.
Miller says that while the first step would be to capture the carbon dioxide from sources where it is concentrated, the ultimate goal would be to snatch it out of the air. A S2P system that includes atmospheric carbon dioxide capture could produce carbon-neutral liquid fuels.
The prototype device, called the Counter Rotating Ring Receiver Reactor Recuperator (CR5, for short), will break a carbon-oxygen bond in the carbon dioxide to form carbon monoxide and oxygen in two distinct steps. It is a major piece of an approach to converting carbon dioxide into fuel from sunlight.
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Sandia research team calls this approach "Sunshine to Petrol" (S2P). "Liquid Solar Fuel" is the end product — the methanol, gasoline or other liquid fuel made from water and the carbon monoxide produced using solar energy.
CR5 inventor Rich Diver says the original idea for the device was to break down water into hydrogen and oxygen. The hydrogen could then fuel a potential hydrogen economy.
The Sandia researchers came up with the idea to use the CR5 to break down carbon dioxide, just as it would water. Over the past year they have shown proof of concept and are completing a prototype device that will use concentrated solar energy to reenergize carbon dioxide or water, the products of combustion. This will form carbon monoxide, hydrogen, and oxygen, which ultimately could be used to synthesize liquid fuels in an integrated S2P system.
Coresearchers on the project are Jim E. Miller and Nathan Siegel. Project champion is Ellen B. Stechel, manager of Sandia's Fuels and Energy Transitions Department.
Stechel says that researchers have known for a long time that theoretically it might be possible to recycle carbon dioxide, but many thought it could not be made practical, either technically or economically and therefore not much effort has been put toward the research until now.
"Not only did we think it was possible, the team has developed a prototype that they fully anticipate will successfully break down carbon dioxide in a clever and viable two-step process," she says.
Stechel notes that one driver for the invention is the need to reduce greenhouse gases.
"This invention, though probably a good 15 to 20 years away from being on the market, holds a real promise of being able to reduce carbon dioxide emissions while preserving options to keep using fuels we know and love," she says. "Recycling carbon dioxide into fuels provides an attractive alternative to burying it."
