Invented a system to create fuel, literally, from the air
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Posted on November 8, 2021
Swiss engineers have devised a prototype that creates energy by combining atmospheric CO2 and water and that can be used to power airplanes.
We are increasingly used to electric cars, solar panels and generally cleaner energy sources. However, heavier means of transport such as airplanes or ships -which currently contribute 8% of the total carbon dioxide emissions attributed to human activity- still require hydrocarbon-based fuel, as really efficient propulsion systems are not yet devised.
Now this could all turn upside down. Because a group of Swiss researchers have invented and tested a method to create fuels from carbon dioxide (CO2), water and sunlight. That is, from the air. The results have just been published in the journal 'Nature'.
There are alternative energies that are less famous than other traditional ones such as wind or solar, but that can be very useful in the short term, such as synthetic fuel. It is a zero-emission fuel that is manufactured from carbon dioxide and hydrogen. And, in principle, nothing more. Because these two elements combined, thanks to the power of sunlight, give rise to a hydrocarbon chain that can be transformed into fuel suitable for combustion engines such as cars, trucks, airplanes or ships. All this has been known for years; however, scientists have not yet managed to create efficient equipment that can exploit this vein.
Imitating plants
This is what Aldo Steinfeld's team from the Swiss laboratory ETH Zürich proposed. In reality, his system 'reinvents' the natural process of photosynthesis: plants absorb atmospheric CO2 and water and, with sunlight providing the energy, convert these raw materials into organic molecules. And that's how Steinfeld's prototype works, although the process is divided into three stages.
At first, the equipment absorbs CO2 and water from the atmosphere and stores them. At that moment, it comes into contact with a basalt rock, which absorbs the unwanted carbon - and which, over time, will become a solid. The second step involves energy from sunlight, which heats up a material called cerium oxide, which, when it reaches certain temperatures, reacts with both CO2 and water. The reaction with CO2 creates carbon monoxide and hydrogen is generated from the water. In both cases, the by-product (or waste) is oxygen, which is vented to the atmosphere without negative impact. What remains -and the process will continue- is a mixture of carbon monoxide and hydrogen, called synthesis gas, which is used to make many things like diesel.
The last part is to convert the syngas into organic molecules. For the hydrocarbons that make up jet fuel, an industrial chemist would normally resort to what is known as the Fischer-Tropsch process, or the chemical process for the production of liquid hydrocarbons such as gasoline, kerosene, or diesel. But Steinfeld's team chooses another method that creates methanol instead of the aforementioned hydrocarbons.
Creating methanol on the roof of the laboratory
The prototype was installed on the roof of the ETH Machine Laboratory Building. This team has produced, on average, 32 millilitres of pure methanol for every seven hours of work each day, a fairly small amount "but which proves that the system is viable", they say. A rough calculation suggests that, to replace the entire current fuel volume (about 414,000 million litres in 2019) with synthetic, 45,000 square kilometres of properly isolated land would be necessary. Or, in terms that seem less spectacular and expensive, about 0.5% of the area of ??the Sahara desert.
Its creators admit that the cost of the initial investment in the first plants "would exceed that of the fossil kerosene that it must replace". Therefore, they ask for "policy support to allow the widespread deployment of these fuels leading to reductions in pollutants". In other words, investment aid to achieve, in the long term, a new cleaner fuel.
Source: ABC
