Chinese scientists are moving technology that converts greenhouse gases into aviation fuel out of the laboratory and towards large-scale production.
Global jet fuel prices surged to US$175 a barrel in March – a year-on-year leap of 94.4 per cent – and broke through the US$200 mark in April, more than doubling the cost from a year earlier. Fuel costs have forced airlines to cancel flights.
As energy prices spiked amid the war on Iran, a team from the Shanghai Advanced Research Institute of the Chinese Academy of Sciences (CAS) unveiled an industrial pathway for turning carbon dioxide into jet fuel.
Their study – published on April 15 in ACS Catalysis, a flagship journal in the field – focuses on turning carbon dioxide directly into long-chain chemicals that can be made into jet fuel.
The process resembles running combustion backwards: waste gas meets water, and the reaction reassembles the molecules into an energy-dense liquid fuel.
For years this chemical process has been held back by two stubborn obstacles: carbon chains struggle to grow, and the ability to target the most valuable long-chain products remains low.
To break through these barriers, the researchers designed an iron-based catalyst modified with both potassium and aluminium.
During reactions, this catalyst naturally forms a special interface where two different materials meet. That meeting point is what makes the catalyst work so well. It speeds up reactions and helps create molecules of just the right size.
The results are impressive: at just 330 degrees Celsius (626 Fahrenheit) and moderate pressure, the catalyst produces 453.7 milligrams of heavy olefins – the building blocks of liquid fuel – per gram of catalyst per hour. Among those, the portion that can be turned directly into jet fuel reaches 252.7 milligrams per gram per hour.
Far more telling for industry, the catalyst held its performance steady through an 800-hour continuous run, a signal that the technology might be ripe to move out of the lab and onto the factory floor.
A CAS statement on Monday said the study provided a simple strategy for making high-carbon olefins and jet fuel-range products with unprecedented efficiency.
The push to commercialise carbon dioxide-derived fuels is already under way in China. Feynman Dynamics, a start-up at the forefront of this field, signed an agreement with the government of the Inner Mongolia autonomous region in October to build a project capable of producing 3,000 tonnes of electro-synthesised sustainable aviation fuel each year.
Hu Shi, the company’s founder and a Tianjin University professor, cautioned that turning clever lab chemistry into certified jet fuel would be a separate marathon.
“The aviation industry requires airworthiness certification to confirm both safety and sustainability, and right now the industry does not recognise fuel made via carbon dioxide hydrogenation,” Hu said.
“This route is like inventing a new drug. You have positive laboratory results, you have built a pilot line that proves you can mass-produce it, but phase one and phase two clinical trials have not been done yet.”
“What Feynman Dynamics is making is real jet fuel that has gone through that airworthiness certification,” he added.
The company’s own process marries electrocatalysis with thermocatalysis. Renewable electricity first splits carbon dioxide into carbon monoxide and oxygen, and then a time-tested industrial process known as Fischer-Tropsch synthesis converts that carbon monoxide into liquid hydrocarbons, the aviation-grade portion of which is jet fuel.
Hu sees making fuel with electricity as the best long-term answer for the industry.
“Aviation simply cannot go electric – planes must fly nonstop, can’t recharge in the air, and the energy they need is far too great for batteries to handle, except in tiny demonstration projects,” he said.
“Turning waste cooking oil into sustainable jet fuel already works, but the supply of used oil is fundamentally limited. We expect the carbon dioxide route to reach cost parity within a decade, turning a greenhouse gas from a global problem into a steady stream of jet fuel.” -- SOUTH CHINA MORNING POST
