Harward researchers claim technology to change carbon-dioxide into fuel
08 June 2018
A team of scientists from Harvard University and the company called Carbon Engineering on Thursday announced that they have found a method to cheaply and directly pull polluting carbon-dioxide out of the atmosphere.
They say, if their technique is successfully implemented at scale, it could reverse the problem of climate change and give humanity a decisive new tool in the race against a warming planet.
Their research also suggests that people will soon be able to produce gasoline and jet fuel from little more than limestone, hydrogen, and air. By using industrial scale carbon scrubbers, the researchers hopes to eventually build a new industrial empire to recycle greenhouse gases directly from the atmosphere to produce much-needed fuels.
The new technique is also cheaper, considering that it would take anywhere between $94 and $232 to remove one metric tonne of carbon dioxide from the atmosphere against the $600 per metric tonne cost that a panel of experts estimated in 2011.
The paper says the same technology can be used to remove carbon dioxide from burning gasoline and that it would cost between $1 and $2.50 to remove the carbon dioxide released by burning a gallon of gasoline in a modern car.
“If these costs are real, it is an important result,” said Ken Caldeira, a senior scientist at the Carnegie Institution for Science. “This opens up the possibility that we could stabilize the climate for affordable amounts of money without changing the entire energy system or changing everyone’s behavior.”
The team published their results Thursday morning in Joule, a new American scientific journal printed by the publishers of biology journal Cell.
“What we’ve done is build a [direct-air capture] process that is—as much as possible—built on existing processes and technologies that are widespread in the world,” said David Keith, a professor of applied physics at Harvard and the lead author of the new study. “That’s why we think we have a reasonable possibility of scaling up.”
Keith is also a founder and executive chairman of Carbon Engineering, a Bill Gates–funded company that has studied how to directly remove carbon dioxide from the atmosphere.
Carbon Engineering says the technique unveiled today has already been implemented at its small, pilot plant in Squamish, British Columbia. It is currently seeking funding to build an industrial-scale version of the plant, which Keith says it can complete by 2021.
Their technique, although chemically complicated, is simple considering that Keith and his colleagues grafted a cooling tower onto a paper mill as the first major step in the new technology.
First, outside air is sucked into the factory’s “contactors” and exposed to an alkaline liquid. These contactors resemble industrial cooling towers: They have large fans to inhale air from the outside world, and they’re lined with corrugated plastic structures that allow as much air as possible to come into contact with the liquid. In a cooling tower, the air is meant to cool the liquid; but in this design, the air is meant to come into contact with the strong base. “CO2 is a weak acid, so it wants to be in the base,” said Keith.
Second, the now-watery liquid (containing carbon dioxide) is brought into the factory, where it undergoes a series of chemical reactions to separate the base from the acid. The liquid is frozen into solid pellets, slowly heated, and converted into a slurry. Again, these techniques have been borrowed from elsewhere in chemical industry: “Taking CO2 out of a carbonate solution is what almost every paper mill in the world does,” Keith said
Finally, the carbon dioxide is combined with hydrogen and converted into liquid fuels, including gasoline, diesel, and jet fuel.
Oil companies convert hydrocarbon gases into liquid fuels every day, using a set of chemical reactions called the Fischer-Tropsch process. But it’s key to Carbon Engineering’s business: It means the company can produce carbon-neutral hydrocarbons.
Carbon Engineering claims that by burning the company’s gas in the car, no fresh carbon-dioxide is released from the tailpipe and into Earth’s atmosphere as this carbon dioxide came from the air in the first place.