Overview on CO2 valorization: challenge of molten carbonates
Déborah Chery, Virginie Lair and Michel Cassir*
Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, PSL Research University, Paris, France
The capture and utilization of CO2 is becoming progressively one of the significant challenges in the field of energetic resources. Whatever the energetic device, it is impossible to avoid completely the production of greenhouse gas, even parting from renewable energies. Transforming CO2 into a valuable fuel, such as alcohols, CO, or even C, could constitute a conceptual revolution in the energetic bouquet offering a huge application domain. Although several routes have been tested for this purpose, on which a general panorama will be given here, molten carbonates are attracting a renewed interest aiming at dissolving and reducing carbon dioxide in such melts. Because of their unique properties, molten carbonates are already used as electrolytes in molten carbonate fuel cells; they can also provoke a breakthrough in a new economy considering CO2 as an energetic source rather than a waste. Molten carbonates’ science and technology is becoming a strategic field of research for energy and environmental issues. Our aim in this review is to put in evidence the benefits of molten carbonates to valorize CO2 and to show that it is one of the most interesting routes for such application.
Keywords: CO2 valorization, electrolysis, molten carbonates, carbon monoxide, carbon
The Problematic of CO2 and Its Valorization
Global warming due to rising levels of greenhouse effect gases, such as atmospheric carbon dioxide, and energy consumption are the major challenges in the energetic field. Decreasing carbon dioxide emissions is a key issue but not the only one; thus, it is becoming compulsory to capture and reuse this gas in an efficient mode as a new source of fuels. There are different approaches to this stimulating problem.
Some Facts
Carbon dioxide is in the heart of fundamental processes over millions of years on Earth. It allows stocking solar energy through synthesis, and it is a key molecule for producing fossil fuels and, thus, it is an indicator of the consumption of energy from fossil fuels. Of course, the negative effect of CO2 in the atmosphere is dramatic and contributes to a significant increase in the temperature of our planet, which is becoming alarming. Concentration of this gas is nowadays increasing by more than 2 ppm per year, reaching 400 ppm against 280 ppm in the preindustrial era. The challenge is to store and to transform the CO2 into valuable chemicals and fuels along with a better understanding of the physicochemical properties and behavior of CO2. This would be an extraordinary input in the development of sustainable energy.
Key Molecule in a New Energetic Economy
Carbon capture and storage (Sequestration) (CCS) is a potential method to allow the continued use of fossil-fueled power stations while preventing emissions of CO2 from reaching the atmosphere.
