Carbon-Capture System Upgrades Existing Power Plants

Thursday, June 27 2013

Many researchers around the world are seeking ways to “scrub” carbon dioxide from the emissions of fossil-fuel power plants, as a way of curbing the gas that is considered most responsible for global climate change. Most such systems, however, rely on complex plumbing to divert the steam used to drive the turbines that generate power in these plants, and such systems are not practical as retrofits to existing plants.
Now, researchers at MIT have come up with a scrubbing system that requires no steam connection, operates at lower temperatures, and essentially acts a “plug-and-play” option that could be added relatively easily to any existing power plant.

The system is a variation on a well-studied technology that uses chemical compounds called amines, which bind with CO₂ in the plant’s emission stream and can then release the gas when heated in a separate chamber. The conventional process, however, requires that almost half of the power plant’s low-pressure steam be diverted to provide the heat needed to force the amines to release the gas. That massive diversion would require such extensive changes to existing power plants that it is not considered economically feasible as a retrofit.

In the new system, an electrochemical process replaces the steam-based separation of amines and CO₂. This system only requires electricity, so it can easily be added to an existing plant.