EPFL_CO2
EPFL_CO2

CO2: What if CO2 could be turned into fuel?

22. 01. 20.

CO2: What if CO2 could be turned into fuel?

EPFL has developed a concept for capturing and recycling CO2.

 

Although the electrification of private transport could be one of the solutions for reducing the CO2 emissions linked to transport, reducing those generated by public transport and freight (buses and trucks) is more problematic.

Researchers from the Faculty of Engineering Sciences and Techniques at the EPFL (The Swiss Federal Institute of Technology in Lausanne) are proposing a new solution to reduce the emissions linked to this sector by 90%: capture the CO2 directly from the exhaust, liquefy it in a tank located on the vehicle’s roof and convey it in liquid form to the pump, where it will be converted into conventional fuel by renewable energy.

EPFL_CO2

A complex process on board the vehicle

Several technologies introduced by the EPFL have been combined to allow the CO2 to be captured then converted from the gas to the liquid state, while making maximum use of the available energy on board, such as the engine’s heat. In their study, the scientists use the example of an HGV.

First of all, the vehicle emissions are recovered directly from the exhaust and cooled, the water is then separated from the gases. In order to isolate CO2 from the other gases (nitrogen and oxygen), the gases are passed though a modulated-temperature adsorption system, using Metal Organic Framework (MOF) materials or adsorbents, designed specially to absorb CO2. These materials are developed by the Energypolis teams at EPFL’s Valais Wallis campus. Once saturated with CO2, this material is heated to extract pure CO2. High-speed turbochargers developed by the EPFL campus in Neuchâtel use the engine’s heat to compress the CO2 and turn it into liquid. The latter is stored in a tank. It can be converted into conventional fuel in a special station, using green electricity.

The entire process will take place in a 2 x 0.9 x 1.2 m capsule, located above the driver’s cab and representing only 7% of the vehicle’s payload. The researchers calculate that a truck consuming 1 kg of conventional fuel could produce 3 kg of liquid CO2 and that the conversion is made with no energy penalty.

As for the 10% of non-recyclable CO2 emissions, the researchers propose offsetting them by using fuel derived from biomass.

EPFL_CO2

Applicable to all types of transport

In theory, this system could work on all types of heavy goods vehicles, coaches and even boats, whatever fuel is used. The advantage of this system on an industrial level is that, unlike electric or hydrogen solutions, it enables the fleet of HGVs that are already in use on our roads to be retained, while making them carbon neutral.

Now that the patent for this system has been filed, the researchers hope to improve their process and miniaturise their system to make it suitable for use on cars with thermal engines that will then operate on a quasi-closed circuit using greenhouse gases.