Researchers at the University of Oxford have successfully developed a way of turning CO2 into a viable form of jet fuel. Effectively reversing the combustion process, this new method could open the door for "carbon-neutral" jet fuels in the future.
The need for carbon-neutral fuels is growing
Over the last few decades, the aviation industry has been pulling out all the stops to find ways to reduce its so-called "carbon footprint". Initiatives have included carbon offsetting through planting trees or investing in renewable energy sources in order to compensate for the large amounts of CO2 emitted by aircraft on a daily basis.
Other proposals included experimenting with more environmentally friendly and sustainable fuel sources including hydrogen, or eliminating the need to use fossil fuels altogether with pure electrical engines.
But a new weapon has been added to the industry's arsenal from a team of researchers at Oxford University. In a study published in Nature Communications yesterday, a novel way to "reverse" the combustion process has been successfully achieved.
This experimental process takes carbon dioxide (widely considered the most abundant of greenhouse gases) and converts it into a viable fuel through an iron catalyst-based chemical reaction. At present, the process has only been conducted under laboratory conditions and would need to be replicated and upscaled to be a viable option for the aviation industry.
However, the chemical engineers behind the process are confident it could be a "game-changer" for the future of commercial flights.
“Climate change is accelerating, and we have huge carbon dioxide emissions,” says Tiancun Xiao, a senior research fellow at Oxford’s Department of Chemistry and an author of the paper.
"The infrastructure of hydrocarbon fuels is already there. This process could help relieve climate change and use the current carbon infrastructure for sustainable development.”
This innovative process reverses combustion under special conditions
As you can probably remember from your high school chemistry lessons, when hydrocarbons are burned, the result is carbon dioxide, water, and lots of energy. This new process basically reverses that through a process called the organic combustion method, OCM for short.
A mixture of citric acid, hydrogen, and a catalyst made of iron, manganese, and potassium are heated to 662 degrees Fahrenheit (350 degrees Celsius) and when carbon dioxide is added to the mix, the product is a liquid fuel that would work in a jet engine. The entire process was run in a stainless-steel reactor but was only able to produce a few grams of the substance.
To make this process commercially viable, larger amounts of it could theoretically be made using large amounts of CO2 removed from the air through sequestration either in a specially designed factory or directly from the air at the production facility.
The team is confident that once upscaled, the new method would be cheaper than other existing methods that turn hydrogen gas and water into fuel, such as hydrogenization.
Xiao foresees a future where such production facilities could be placed next to steel or cement factories or coal-burning power plants to capture and convert any carbon dioxide emissions from them.
But to be truly sustainable, the production facility and the carbon capture processes would need to be powered through renewable technologies themselves, like solar or wind.
“You need to use renewable electricity,” Oskar Meijerink, project lead for future fuels at SkyNRG says. “The challenge is if we are using CO2 from a steel mill, how can we push the steel mill to be carbon neutral itself? The perfect solution would be to have all these industries be more sustainable, and use this to do direct-air capture.”
If this innovative process is ever realized, carbon dioxide would become both a waste product and a source of fuel at the same time.
Truly a game-changer!
You can read the full study at Nature Communications here.