Adsorption de CO2 à partir de gaz de synthèse : modélisation de la sélectivité, la capacité et la facilité de régénération de nouveaux adsorbants (CO2 adsorption from synthesis gas mixtures: understanding and Selectivity of new adsorbents)

The design of new environmentally friendly and efficient adsorbents for CO2 separation requires a quantitative link between the adsorbent properties and adsorption capabilities. One can use molecular simulations to generate an empirical correlation between some descriptors of the adsorbent, as the pore diameter, surface area, etc. with macroscopic properties, as the adsorbed amount at a given pressure. However, this approach requires a complete microscopic description of the adsorbent (atomic positions, intermolecular potentials, etc.) and demands a great number of time consuming simulations. In this work we develop a methodology, which explicitly takes into account the adsorbent properties, such as the pore diameter, density, pore shape and chemical composition. The objective is to establish quantitative correlations between the above-mentioned parameters and the forces that govern physisorption in porous media, i.e. van der Waals forces and electrostatic interactions. Thus, the optimal properties of the adsorbent for CO2 separation are identified. In parallel to these theoretical studies, a series of potentially interesting adsorbents for CO2 separation by PSA were tested experimentally. A systematic study of the influence of the metal center on the separations of CO2/CH4 and CO2/CH4/CO mixtures was carried out on MOFs presenting coordinatively unsaturated sites. In the case of zeolites, the effect of the framework composition (Si/Al ratio) on the separation properties was studied. The cyclic capacities and selectivities were determined by breakthrough experiments. Materials presenting a good compromise between selectivity and working capacity under typical PSA conditions were identified. Finally, a comparison between the prediction of the adsorption model and the breakthrough experiments is carried out.

• Auteur : Edder GARCIA (IFPEN), direction de thèse : C. Jallut (LAGEP) – G. Pirngruber (IFPEN)
• Soutenance : 22 octobre 2012
• Financement :