Over the past decade, the aviation industry has sought ways such as buying carbon offsets or modifying carbon (tree planting projects or wind farms) to compensate for the carbon dioxide emitted by jets in flight. Meanwhile, San Francisco, Chicago and Los Angeles airports, along with dozens of European airports, are using greener alternative fuels to help achieve their carbon reduction goals.
A team of researchers at the University of Oxford in the UK has now developed an experimental process that could convert carbon dioxide (the greenhouse gas produced by all gasoline engines) into jet fuel. If successful, the process, which uses an iron-based chemical reaction, will help reduce aircraft carbon emissions to zero.
The experiment was recently published in the journal Nature Communications It has been reported, performed in the laboratory, and needs to be repeated on a larger scale. But the chemical engineers who designed and implemented the process hope their approach can be transformative in the context of climate change. Tiancon XiaoSays a senior researcher in the Department of Chemistry at Oxford University and one of the authors of the article:
Climate change is accelerating and we have a lot of carbon emissions. There is currently a burning hydrocarbon infrastructure. This process can help reduce the severity of climate change and use existing carbon infrastructure for sustainable development.
When fossil fuels, such as oil or natural gas, burn, their hydrocarbons are converted to carbon dioxide and water, releasing energy in the process. The new experiment reverses this process using a solution called the Organic Combustion Method (OCM) to convert carbon dioxide back into fuel.
By adding heat (350 degrees Celsius) to citric acid, hydrogen and a catalyst made of iron, manganese and potassium to the carbon dioxide, the researchers produced a liquid fuel that runs on a jet engine. The experiment was performed in a stainless steel reactor and only a few grams of material were produced. In the laboratory, carbon dioxide came from a chamber; But the idea of implementing this approach in the real world is to capture the greenhouse gases from the plant or remove them directly from the air in order to remove them from the environment.
Carbon dioxide is the most abundant greenhouse gas and is produced by factories, cars and wood burning during events such as wildfires, forests and agriculture. Releasing carbon dioxide from the atmosphere may help reduce global warming; However, the world’s carbon emissions have been rising for decades and are on track to warm the Earth by 2 degrees Celsius by the end of the century.
Xiao and his colleagues say the new method is cheaper than existing methods, which convert hydrogen and water into fuel (a process called hydrogenation), largely because it consumes less electricity.
Xiao envisions a jet fuel plant located next to a steel or cement plant or a power plant that burns coal and uses the extra carbon dioxide to produce fuel. This process can involve the release of carbon dioxide from the atmosphere, called “direct absorption from the air.”
The authors say the catalyst used in the experiment is abundant on the ground and requires fewer steps than other methods of synthesizing high value-added chemicals. An expert who did not participate in the experiment says that the concept seems promising; Provided that researchers discover how to produce higher quantities of jet fuel in the laboratory to produce higher quantities in the experimental plant.
Joshua Hin“Scaling up is always a problem, and when you go to larger scales, you run into the unexpected,” says Associate Professor of Mechanical and Chemical Engineering at Dayton University in the United States. “But in terms of a long-term solution, the idea of a rotating carbon economy can certainly be implemented in the future.” In a rotating carbon economy, carbon dioxide is converted into both a waste stream and a fuel source.
If the replacement jet fuel plant could run on electricity from wind or solar energy, there would be a huge change in carbon footprint. According to himOscar Migerink, The leader of the Future Fuels project at the Dutch company SkyNRG, which works in the field of sustainable aviation fuels:
In this way, the jet fuel and the carbon dioxide source are produced in a sustainable way … It is necessary to use electricity that is produced from renewable sources. But the challenge is, if we use carbon dioxide produced in a steel plant, how can we make that steel plant carbon neutral? The great solution is to make all of these industries more sustainable and use the new method to absorb carbon dioxide directly from the air.
In addition to testing Oxford and its new carbon dioxide-based jet fuel, other groups are working on alternative fuels to conventional jet fuel. These alternative fuels are made from raw materials that include municipal solid waste, straw, wood biomass, and even waste from cooking oil. Xiao believes that the new fuel has the power to compete with these options. In 2006, he founded the green fuel company Oxford Catalysts, now known as Velocys. The company is building alternative aircraft fuels for various companies using municipal waste as raw materials and diesel fuel for trucks using waste paper and wood at factories in Mississippi. Xiao is discussing a new method of converting carbon dioxide with several major industry partners. “There is no big challenge,” he says. “But we need to optimize the process and increase its efficiency.”