Carbon from the air is supposed to power jet engines
Carbon dioxide is the main culprit when it comes to climate change.
That’s why scientists are working to turn the emissions upside down and plan to pull the carbon dioxide out of the air again.
And if it is possible, why not use CO 2 from the air to produce jet fuel instead of relying on fossil fuels?
The carbon in the air becomes fuel
New technology uses CO 2 from the air as a raw material to produce fuel for airplanes.
Electrolysis produces syngas
The carbon dioxide is mixed with water vapor and the two gases are pumped into a so-called electrolysis cell. When a current is applied, the molecules split apart. This produces carbon dioxide and hydrogen, so-called syngas, which can be further processed into aircraft fuel.
Engineers have now found the answer to this question. The Swiss company Climeworks has developed a filtering device that extracts CO 2 from the air and stores the gas in tanks.
In addition, the German company Sunfire has built a processing plant that converts CO 2 and water vapor into so-called syngas. It can then be processed further into everything from diesel, to wood spirits to jet fuel free of mineral oil.
The filter device works by passing the air through filters that trap the CO 2 molecules.
Once the filters are saturated with carbon dioxide, the chamber is sealed and heated to 100 degrees. The heat releases CO 2 from the filters and a vacuum pump then sucks the gas into a tank.
Filter equipment with 118 units that suck CO2 from the air and pump clean air out. The equipment was commissioned in 2017 in Hinwil, Switzerland.
The carbon dioxide from the tank is mixed with water vapor in a two-part so-called electrolysis cell, which is filled with CO 2 and water vapor on one side and normal air on the other.
A membrane separates the materials but allows ions through.
Outside the membrane lies an electric circuit and when a current is applied to it, the “exhaust” is drawn in the form of oxygen from the mixture of CO 2 and H 2 O, leaving CO , carbon dioxide and H 2 or hydrogen.
Carbon dioxide and hydrogen are so-called syngas, which can then be refined into hydrocarbon chains that are suitable for fuel production.
Airplanes should fly on plastic waste
Food packaging, diapers, plastic cups and other plastic waste end up in landfills in tons every day or are burned in polluting incinerators.
Now engineers in England plan to use half a million tons of such waste to make fuel for airplanes.
The company Altalto plans to build a processing plant using its new “trash-to-fuel” technology in the English city of Immingham.
A fuel station processes carbon chains from packaging
Plastic household waste, such as packaging, will be converted into jet fuel using steam and nuclear reactors.
Trash becomes gas
Plastic waste contains carbon and hydrogen. In order to extract the materials from the debris, engineers pump steam and fire through the debris at high temperatures. Since this process is deficient in oxygen, the waste does not burn. Instead, single atoms are released and they form new bonds. From this comes carbon and hydrogen, so-called syngas.
Gas becomes liquid raw material
The syngas is fed into a so-called Fischer-Tropsch reactor. In it, the atoms react with metals, usually iron and cobalt. The chemical reaction separates the carbon dioxide molecules into carbon and fire and separates the hydrogen molecules into single hydrogen atoms. Next, carbon and hydrogen are linked together to form long hydrocarbon chains. The chains are cooled with water and the gas condenses into a liquid form.
From raw materials to fuel
Hydrogen is added to the hydrocarbon under high pressure and high temperature. The hydrogen cleaves the carbon chains, which shorten as a result. The aim is for the chains to be 8 – 15 carbon atoms long, as their freezing point is then around minus 50 degrees and boiling point around 175 degrees. It is well suited for the heat that aircraft are exposed to in the air.
The plastic in the trash contains carbon and hydrogen atoms that can be extracted when a stream of water and oxygen heat the trash to more than 700 degrees.
The gas from the waste is then pumped through a nuclear reactor, where metals cause the gas to react and split into carbon, oxygen and hydrogen atoms.
The individual atoms now link together into long carbon chains that are cooled down. The cooling condenses the gas into a liquid.
The chains are relatively long and this means that their boiling point is too high for jet engines.
Therefore, pure hydrogen is injected into the liquid under high pressure, which splits the chains into shorter parts.
In this way, a liquid is obtained that remains liquid in the freezing cold of the high air where jets fly, but burns as efficiently as possible.
Until now, the price is too high and it is difficult to convert gas from scrap to liquid fuel, but the new processing plant uses a reactor that does the job faster and cheaper, because it consists of more and smaller pipelines for both gas and coolant.
A solar cell plant creates fuel from the sea
CO 2 is not only undesirable in the atmosphere, as the oceans also absorb carbon.
The amount of CO 2 is up to 125 times greater in each cubic meter of water than in air.
An international team of scientists has now found a solution to how to filter CO 2 from the sea and then use the carbon to produce jet fuel that is free from oil.
Scientists plan to use floating solar cell plants 100 meters in diameter to make jet fuel from seawater.
The energy for the process will come from solar cell plants that are 100 meters in diameter. These are a kind of solar farm that floats on the open ocean.
The solar farms use three technical solutions. First, electrolysis cells split the water molecules apart to form hydrogen.
A filter then divides the sea into alkaline and acidic water, and in the acidic water, CO 2 is converted into gas bubbles – like in mineral water – which are trapped.
Finally, the hydrogen and CO 2 are passed through a nuclear reactor, where the substances react and form methanol that can be used as fuel.
The rest is normal potable water, free of CO 2 .
Oil from algae is to be burned in jet engines
Through photosynthesis, algae convert sunlight into energy, which is then stored in fatty substances called lipids.
The materials consist, among other things, of fatty acids that contain oil, which can be used to produce aircraft fuel.
A common method of extracting the oil from algae is to dry and grind them, then mix the powder with methanol and chloroform. However, this method is very energy intensive.
Now researchers at the University of Utah have come up with a new method.
Dive into the science of green jet fuel
Scientists are developing four new methods for producing green jet fuel.
Fuel can be produced from carbon dioxide absorbed from the atmosphere, and in this article in Physics Today you can read about the state of so-called negative emissions.
Waste can be converted into fuel and this is done with the so-called Fischer-Tropsch synthesis – a technique described in this article .
Carbon dioxide in the sea can also be used for fuel production with so-called solar farms. Scientists describe the idea here .
Finally, you can read more aboutbrand new technology that makes it possible to extract oil from algae, which can then be used as fuel. Researchers from the University of Utah are developing this technology.
Algae powder is shot into a chamber under high pressure, where the powder meets an equally powerful blast of the solvent hexane.
The collision tears the algal cells apart and the lipids bind to the hexane.
The fat can then be extracted in the form of a thick black oil that can be converted into jet fuel.
