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EPFL team develops on-board system to capture CO2 from trucks; reducing emissions by 90%

Researchers at EPFL have patented a new concept that could cut trucks’ CO2 emissions by almost 90%. The EPFL system captures CO2 directly in the trucks’ exhaust system and liquefies it in a box on the vehicle’s roof. The liquid CO2 would then be delivered to a service station and where it will be turned back into fuel using renewable energy.

The project is being coordinated by the Industrial Process and Energy Systems Engineering group, led by François Maréchal, at EPFL’s School of Engineering. The patented concept is the subject of an open-access paper published in Frontiers in Energy Research. In their study, the scientists used the example of a delivery truck.

First, the vehicle’s flue gases in the exhaust pipe are cooled down and the water is separated from the gases. CO2 is isolated from the other gases (nitrogen and oxygen) with a temperature swing adsorption (TSA) system, using metal-organic frameworks (MOFs) adsorbent, which are specially designed to absorb CO2. Those materials are being developed by the Energypolis team at EPFL Valais Wallis, led by Wendy Queen.

Once the material is saturated with CO2, it is heated so that pure CO2 can be extracted from it. High speed turbocompressors developed by Jürg Schiffmann’s laboratory at EPFL’s Neuchâtel campus use heat from the vehicle’s engine to compress the extracted CO2 and turn it into a liquid. That liquid is stored in a tank and can then be converted back into conventional fuel at the service stations using renewable electricity.

Fenrg-07-00143-g003

Simple heat and mass flows for CO2 capture from diesel engine exhaust: exhaust cooling, TSA cycle, product CO2 compression, and liquefaction. Sharma and Maréchal


The whole process takes place within a capsule measuring 2 m x 0.9 m x 1.2 m, placed above the driver’s cabin.

The weight of the capsule and the tank is only 7% of the vehicle’s payload. The process itself uses little energy, because all of its stages have been optimized.

—François Maréchal

The researchers’ calculations show that a truck using 1 kg of conventional fuel could produce 3kg of liquid CO2, and that the conversion does not involve any energy penalty.

Only 10% of the CO2 emissions cannot be recycled, and the researchers propose to offset that using biomass.

The system could theoretically work with all trucks, buses and even boats, and with any type of fuel. The advantage of this system is that, unlike electric or hydrogen-based ones, it can be retrofitted to existing trucks in order to neutralize their impact in terms of carbon emissions.

Resources

  • Sharma Shivom, Maréchal François (2019) “Carbon Dioxide Capture From Internal Combustion Engine Exhaust Using Temperature Swing Adsorption” Frontiers in Energy Research doi: 10.3389/fenrg.2019.00143

Comments

GdB

For medium and light trucks also please!!!

mahonj

If this is real, it is quite a boon to all land and sea transport.
It sounds too large for cars and medium trucks, but if you could do buses and large trucks, it would be really good.
Also boats.
Then, you have the problem of tons and tons of liquid CO2 to dispose of, but it certainly is progress.
Smaller trucks and cars could go electric.
I would not worry about the 10% CO2 you cannot get, 90% is plenty.
Main thing is to really test it and build a CO2 disposal network.

Scott

..or recycle the CO2 to synthetic fuels to use in existing cars.

SJC

Reuse carbon to reduce emissions

Engineer-Poet

You can buy turnkey plants which take CO2 and hydrogen and produce methanol.

gryf

Good point E-P about Methanol plants. Maybe a closed loop Methanol fuel cycle with CCS.
This study makes a good point that even small to medium diesel trucks could use the TSA/liquid CO2 for CCS. However, I believe most ground transportation will go BEV. Even Nikola Motors is now looking at BEV Class 8 trucks. Marine applications would still be a good area, due to long range requirements and the fact that they are already using Methanol in Marine diesels.
What about Air Transportation? Not with diesels, but with an Allam Cycle CO2 turbine. All that is needed is an Onboard Inert Gas Generation
System/Onboard Oxygen System (OBIGGS/OBOGS) that uses membrane technology for gas separation. Air Liquide already has a system for aircraft and helicopters.

Engineer-Poet

Air transportation is going to work out really poorly for Allam cycles because you have the dual weight burden of air separation and dumping low-grade heat to the air (requires contact with a huge mass of air, which means drag).

You're going to be better off burning ammonia.  Ammonia packs roughly 17 MJ/kg, which gives you around 2 kWh/kg even after conversion losses.  That's about 5x better than batteries too.

gryf

Agreed. Ammonia or possibly Kubas Manganese Hydride storage (if it develops) would be better for Air transport.

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