Could dry ice help make carbon scrubbing a reality?

An Arizona startup is proposing to create millions of mechanical devices that would extract CO2 from the air.

Global Research Technologies already has a prototype of the unit, which captures CO2 from air as it passes through a series of "leaves" made from a proprietary substance. Humid air is then passed through the leaves, which washes out the CO2. The pollutant is turned into a gas stream which can then be used in different industrial processes, said the firm's president, Allen Wright.

The "carbon scrubbing" technology, developed by University of Columbia physicist Klaus Lackner, differs from other approaches to carbon capture in that it is designed to capture diluted carbon from the air, rather than capturing it in high concentrations at sources, such as industrial plants or power stations. That means that the units could be positioned anywhere, including next to sequestration points, Wright explained. "A taxicab in Shanghai can emit the carbon, and you could have a device in Montana that captures it," he explained.

"Third world countries are developing at such a pace that it's causing them to put coal-fired power plants online at a ferocious rate," he added. "They will emit CO2 for 50 years, and it's unlikely that any will be fitted with carbon capture technology."

Wright would not reveal any projected efficiency figures for the units, but says that a 40-foot tall system would collect around one tonne of CO2 per day.

Rather than relying on possible cap and trade carbon offsets, the company is looking for direct profits from carbon capture.

"To make it economically viable we cannot look to the cap and trade $25 per tonne value being banded about," he said. "When I go to the grocery store and I buy dry ice from the cooler, that's $2 per pound. That's $4,000 per tonne. That's a lot of money for CO2. So the plan would be to commercialise the technology through these high value, low-volume, niche markets."

Eventually, GRT might sell the units to companies that currently produce CO2 for industrial processes by having it piped in, or by burning expensive natural gas. Potential markets could include everything from large greenhouses, some of which need to pump in CO2 for consumption by plants, through to beverage carbonation and the production of dry ice for industrial blasting methods.

Wright hopes to be ready for commercial production in two years.