CO2 Sponge Could Help In Gradual Move From Fossil Fuels To Cleaner Energy

You can't just flip a switch and immediately shift the world's energy use from fossil fuels to something cleaner like hydrogen. Such change takes time. But a team of scientists reports that we can use a common plastic to make that transition easier.

The polymer "sponge" is a powdery substance that "adsorbs" large amounts of carbon dioxide when under pressure. When a substance adsorbs something, such as CO2, it holds on to it so the CO2 can be used for some other purpose. In this case, the CO2 would be used for a new technology that converts fossil fuels to extremely clean hydrogen gas.

"The key point is that this polymer is stable, it's cheap, and it adsorbs CO2 extremely well. It's geared toward function in a real-world environment," says Andrew Cooper of the University of Liverpool, who led the research. "In a future landscape where fuel-cell technology is used, this adsorbent could work toward zero-emission technology."

In a report at the 248th National Meeting & Exposition of the American Chemical Society (ACS), the world's largest scientific society meeting in San Francisco, Cooper explains that hydrogen made by a conversion process known as integrated gasification combined cycle (IGCC) could be an important element in electricity-generating fuel cells.

The hurdle, Cooper explains, is that IGCC produces both hydrogen and carbon dioxide, which must be separated. This is where his polymer comes in. The adsorbent sponges could be installed in smokestacks at oil- or coal-burning power plants, where they would trap carbon dioxide and expand, much as an absorbent sponge soaks up water.

And because the spongy polymer is adsorbent, it holds on to the CO2 so it can undergo the IGCC process. This requires high pressure to work, he says, and when that pressure is released, the sponge deflates and releases the carbon dioxide, when then can be collected and converted into cleaner compounds.

Cooper's polymer sponge is very stable and very, very strong, standing up even to being boiled in acid. As a result, the research team is confident it would withstand the harsh environment of the inside a power plant's smokestack. This would be a major improvement over current CO2 "scrubbers," - made of plastic, metal or even liquids - which often don't last very long.

Further, the polymer sponge can absorb carbon dioxide without also sucking up water vapor. Cooper explains that the vapor that collects in conventional scrubbers can clog them, limiting their effectiveness.

These advantages are attractive assets for so unattractive material. Perhaps its greatest attraction, Cooper says, is its low cost. "Compared to many other adsorbents, they're cheap," he says, because of the low cost of the carbon molecules used to make the sponges.

By Andy Tully of Oilprice.com