Cleaning up carbon dioxide

Current techniques rely on complex plumbing to divert the steam used to drive the turbines - but such systems are impractical as retrofits to existing plants.

Experts at the Massachusetts Institute of Technology (MIT) have devised a scrubbing system that does not require a steam connection, is operable at lower temperatures and would effectively be classed as a ‘plug and play’ solution that can be added to existing power plants.

The researchers believe their thermal-amine scrubber system is capable of removing up to 90% of CO2

The electrochemical technique, as described in the online journal Energy and Environmental Science, is a variation on a technology which uses amines, a chemical compound that combines with CO2 and releases the gas when heated in a separate chamber.

The amine based system injects a solution at the top of an absorption column which then binds with the CO2 in the emissions stream and is collected in liquid form at the bottom of the process.

A metal electrode electrochemically forces the release of the hazardous gases and the amine molecules are then regenerated and reused.

The researchers believe their thermal-amine scrubber system is capable of removing up to 90% of CO2 produced from a plant’s emissions, using as little as 25% of the power output required by conventional processes.

David Heldebrant, senior research scientist at the Pacific Northwest National Laboratory, suggested: “As with any process, the main questions and uncertainty pertain to the costs and lifetime of the system.”

His team’s system, however, is applicable across a wider range of applications as it does not rely on steam from a boiler.

Heldebrant believes the amine-based system could be used in cement factories and could also help reduce the amount of emissions produced in steel and aluminium works.