The laboratory of chemist James Tour at the Rice University, together with the assistance of the National Institute of Standards and Technology, have produced a porous material which separates CO2 molecules from natural gas and polymerizes them while under pressure naturally provided by the well. When the pressure is released, the CO2 depolymerizes and frees the sorbent material allowing it to separate further CO2 molecules. All this takes place in ambient temperatures, unlike existing CO2 capture technologies which require high-temperatures of about 140 degrees Celsius and consequently use up a significant amount of the energy. In addition, conventional methods for CO2 sequestration use liquid amine-based scrubbers which are corrosive and hard on the equipment.
The Tour laboratory material is inexpensive, and simple to produce. Moreover, it is claimed that the material does not degrade over many cycles. Tour pointed out that “After heating it to 600 degrees Celsius for the one-step synthesis from inexpensive industrial polymers, the final carbon material has a surface area of 2,500 square meters per gram, and it is enormously robust and extremely stable”.
“Our technique allows one to specifically remove CO2 at the source. It doesn’t have to be transported to a collection station to do the separation”, explained Tour. This is becoming increasingly important for cutting down CO2 and other emissions from the oil and gas industry in the face of the latest National Climate Assessment by the White House and the new rules to cut CO2 from power plants in the US.
Tour further added that this technique will enable companies to pump CO2 directly back underground where it has been for millions of years, or alternatively use it for enhanced oil recovery to increase production at oil and natural gas sites. The CO2 can moreover be packaged and sold for other industrial applications.
Natural gas is the cleanest fossil fuel. “The development of cost-effective techniques of separating CO2 during the production process will improve its advantage over other fossil fuels and enable the economic production of gas resources with higher CO2 content that would be too costly to cover using existing CO2 capture technologies”, said Tour.
For a video of the science behind the CO2 capture breakthrough see here.