Turning CO2 emissions into fuel
Researchers at Massachusetts Institute of Technology (MIT) have developed a new system that could potentially be used for converting power plant emissions of carbon dioxide (CO2) into useful fuel for cars, trucks and planes.
Made of lanthanum, calcium, and iron oxide, the membrane is designed to separate out oxygen from carbon dioxide, leaving behind carbon monoxide that can then be turned into a variety of useful fuels.
Carbon monoxide produced during this process can be used as a fuel by itself or combined with hydrogen and/or water to make many other liquid hydrocarbon fuels as well as chemicals including methanol (used as an automotive fuel), syngas, and so on.
Why it was required?
With concentrations of CO2 at their highest in the last 400,000 years, the world needs to remove the greenhouse gas from the atmosphere – as well as cut emissions – if we are to avoid catastrophic climate change.
Although nature has been recycling carbon dioxide for millions of years. Photosynthesis turns sunlight, carbon dioxide and water into sugars which fuel plants, which provide us with food, wood and complex sugars for fuel. But most plants turn less than 1% of the solar energy they receive into useful energy-rich compounds.
The separation is driven by temperatures of up to 990 degrees Celsius, and the key to making the process work is to keep the oxygen that separates from carbon dioxide flowing through the membrane until it reaches the other side.
This could be done by creating a vacuum on side of the membrane opposite the carbon dioxide stream, but that would require a lot of energy to maintain.
In place of a vacuum, the researchers use a stream of fuel such as hydrogen or methane. These materials are so readily oxidized that they will actually draw the oxygen atoms through the membrane without requiring a pressure difference.