Geneva: Scientists have developed a new technology that could cut carbon dioxide emissions from trucks and buses by nearly 90 percent by trapping CO2 inside the flow system, turning it into being liquid and storing it on the vehicle.
The melted CO2 would then be delivered to a service station where it will be converted back into fuel using renewable energy, according to the researchers from the Swiss Federal Institute of Technology Lausanne (EPFL).
They recommend capturing and converting CO2 from gas to liquid in a process that recovers most of the energy available on board, such as heat from the engine.
In the study, published in the journal Frontiers in Energy Research, the scientists used the example of a delivery truck.
First, the vehicle’s exhaust gases in the cooling pipe are cooled down and the water is separated from the gases.
CO2 is separated from other gases such as nitrogen and oxygen by a temperature swing adsorption system, using adsorbent metal-organic frames (MOFs), which are specifically designed to absorb CO2.
As soon as the material is saturated with CO2, it is heated to remove pure CO2, the researchers said.
High-speed turbocompressors developed by EPFL’s Jurg Schiffmann Laboratory 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 to conventional fuel at the service stations using renewable electricity, the researchers said.
“The truck just deposits the liquid when it fills with fuel,” said Francois Marechal from EPFL.
The whole process takes place inside a capsule placed above the driver’s cab.
“The weight of the capsule and tank is only 7 percent of the vehicle’s payload. The process itself uses very little energy, as all levels are increased,” Marechal said.
The researchers’ calculations show that a truck using one kilogram (kg) of conventional fuel could emit 3kg of smelting CO2, and the conversion does not carry an energy penalty.
Only 10 percent of CO2 emissions can be recycled, and the researchers recommend counteracting that by using biofuels, they said.
Theoretically the system could work with all trucks, buses and even boats, and with any type of fuel, the researchers said.
The advantage of this system, unlike those based on electricity or hydrogen, is that it can be reintroduced to existing trucks to neutralize their carbon-neutral impact, they said.