Low-Cost Carbon Filter Process Captures CO2 and Mercury from Coal Fluegas

Chemical Engineering Progress, Jun 2008 by Shelley, Suzanne

ENVIRONMENTAL

A research team at the Univ. of Wyoming's Soft Material Laboratory has developed a simple, low-cost adsorption process, referred to as Carbon Filter Process, which can capture CO2 and mercury from fluegas generated by coalfired power plants.

CO2 and other pollutants are retained on a porous carbonaceous sorbent at ambient temperature and pressure. This is because such CO2-philic carbonaceous materials are selective to CO2 with respect to nitrogen, especially at lower pressures. After it has been saturated with CO2, the sorbent releases CO2 upon heating to approximately 100°C (e.g., with steam). The sorbent is also known to be effective in removing residual mercury from fluegas.

The process (for which a patent is pending) requires neither expensive materials nor fluegas compression or refrigeration. Hence, it can be efficiently integrated with an existing or grassroots power plant.

The cost of recovered CO2 is estimated to be as low as $20/ton prior to compression to pipeline pressure, compared to $47/ton for conventional amine absorption. "This could have a multibillion-dollar impact on the U.S. carbon capture market. An abundant supply of cheap CO2 from electricity producers is good news for enhanced oil recovery (EOR) and enhanced coal-bed methane recovery (ECBMR) operators, because it will lead to higher oil and gas recovery rates in an environmentally sensitive manner, prior to storage," says engineering professor Maciej Radosz.

Pilot tests in existing power plants will be conducted in 2009. More information about the project can be found on the Soft Materials Laboratory website at www.uwyo.edu/sml.