A Robust Process for Effective Carbon Capture (by Parviz Soroushian)

A complete replacement of fossil fuels by renewable sources of energy is not feasible in the short term. Therefore, there is a need to equip fossil fuel power plants with CO₂ capture and sequestration (CCS) capabilities in order to prevent the projected 2°C global warming by 2100. Carbon capture and sequestration would allow for continued use of fossil fuel until a deeper penetration of renewable energy sources into the grid is realized in an orderly fashion. Widespread adoption of CCS technologies would benefit from the availability of processes that lower the cost. Developments in advanced CCS materials and processes are needed in order to achieve this goal. One option is to develop a robust, economical and efficient CCS process based upon the principles of mechanochemistry.

The mechanochemical CCS process will take place in ambient condition within an energy-efficient mill incorporating a nearly dry inorganic sorbent. In the CO₂ sorption step (A), the input of mechanical energy will disturb the structure of the solid sorbent, and will drive CO₂ dissolution and deep diffusion of carbonate anions. This process offers favorable kinetics comparable to the dissolution of carbon dioxide in melts at magmatic temperatures and pressures. The disturbed structure of the sorbent and the dissolved nature of the captured CO₂ enable desorption within the same (mill) chamber at a moderately elevated temperature produced efficiently via microwave irradiation (B); rotation of the mill at a low speed benefits the uniformity of microwave exposure. The mild desorption conditions benefit the stability of the sorbent under repeated sorption-desorption cycles. The mechanochemical CCS process is robust, and can be tailored to accommodate different solid sorbents and the combustion emissions of different fossil fuels. Scale-up of the process benefits the mechanochemical effects by raising the intensity of energy input.