Scientists from MIT have devised a far more efficient means of "scrubbing" carbon dioxide from the gaseous emissions of fossil-fuel power plants.
The new carbon-scrubbing system, developed by scientists from the Massachusetts Institute of Technology, is based upon the use of amines – chemical compounds which attach themselves to carbon dioxide while in the emission stream and separate from them when heated in a separate chamber.
While the use of amines to scour carbon dioxide from emission streams is far from unprecedented, the process devised by the MIT team marks a major advance upon its predecessors due to its efficiency.
The conventional process requires the use of large amounts of energy to generate the heat needed to force the amines to separate from the carbon dioxide – as much as half of the power of a plant’s low-pressure steam. This in turn entails large-scale retrofits to existing plants, which renders it economically unfeasible in most instances.
MIT researchers came up with the idea of using an electrochemical process in lieu of a steam chamber to separate the amines from the carbon dioxide. This systems provides numerous advantages compared to the conventional technology.
The system does not require a steam connection and requires only an electrical connection in order to function effectively as an add-on to existing power plants. It is capable of operating at far lower temperatures and requires much less energy. While conventional carbon dioxide scrubbers consume around 40 per cent of a plant’s power output, this new system only requires around 25 per cent of the plant’s energy output.
Unlike steam-based systems, the electrochemical system can be dialed up or down depending on emissions levels, allowing it to operate with far greater flexibility.
According to the researchers, the technology has the same level of effectiveness as conventional thermal-amine scrubber systems, and is capable of catching up to 90 per cent of the carbon dioxide from a fossil fuel plant’s emission stream.
The new system is described in detail in a paper written by doctoral student Michael Stern, chemical engineering professor T. Alan Hatton, and two other authors and published in the online journal Energy and Environmental Science.
The MIT research team conducted tests on a larger-scale to assess the system’s performance and say it could reach the stage of widespread commercialization within five years to a decade.