CO2-RESTO

CO2-RESTO project aims at developing a technological solution for the carbon dioxide (CO₂) sequestration as clathrate hydrate (CH), both in seawater and under the seafloor. CH are nonstoichiometric solid compounds formed by cage-like crystalline structures of water molecules where a guest molecule – in this case CO₂ - is entrapped under proper conditions of temperature and pressure. The CO₂ storage as CH has been chosen in accordance with their desirable properties if compared to other geological storage pathways, such as higher density than seawater (resulting in a negative buoyancy effect); stability at moderate oceanic depth, storage in solid form, less susceptible to perturbations than fluid flow; storage within porous media (as the sediment of the ocean floor) with a cementing effect. CO2-RESTO addresses some crucial issues, being devoted to obtain a body of knowledge, significantly beyond the state of the art on engineering, chemical and geophysical aspects of CO₂ CH science. The project investigates the proper approaches of CO₂ storage as CH, through in-lab experimental activities for the understanding of hydrodynamics, thermodynamics/kinetics, stability of CO₂ CH formation/dissociation, microscopic characterization of CO₂ CH, the effect of salinity, other chemical compounds and of the presence of other gaseous components. A theoretical model applicable to a CO₂CH reservoir will be developed to characterize a possible natural site for CO₂ CH storage and help the choice and an efficient technological solution for CO₂ injection will be proposed. The project addresses important national long-term PNRR targets. One of the further objectives to 2040 is the installation of CO₂ capture and sequestration plants, both in the electricity and industrial sectors, to bring the energy system to the complete decarbonization by 2050. In addition, the option to store CO₂ as CH is particularly relevant to those economies that produce substantial amounts of CO₂ in their industrial and power operations, but have not proper local geologic storage. The estimates completed so far show that there is a huge capacity for CH storage worldwide, including Europe.