Methodology for thermodynamic peoperties characterization in microfluidic devices ; Méthodologie pour la caractérisation de propriétés thermodynamiques dans des systèmes microfluidiques

Today, knowledge and access to experimental thermodynamic data under high pressure and high temperature conditions is a major challenge in the industry. Being aware of and anticipating the behavior of a fluid regarding its state, viscosity or density is crucial in the oil extraction sector or in substance transformation processes (refining, separation, conversion, .),for example. This thesis work is part of this problematic with the desire to develop tools for high throughput experimentation allowing the rapid acquisition of experimental data in order to improve the accuracy, operator safety and environmental impact by using small quantities of products. In this context, a microfluidic experimental set-up has been developed, as long as experimental methodologies for the construction of phase diagrams of fluid mixtures. The experimental approach is based on the optical detection of bubble points and dew points under high pressure and high temperature conditions (up to 100 bar and 350 °C). We also present the results obtained with silicon-Pyrex microfluidic chips, on ideal systems (CO2 + pentane, CO2 + MEG) and non-ideal systems (water + n-propanol). This research work highlighted the current advantages and limitations of microfluidic approaches for characterizing phase equilibria. In comparison with experimental data from the literature and data from thermodynamic models, this thesis work is a first step towards the development of methodologies adapted to more complex systems for applications in the field of energy, in particular. ; Aujourd’hui, les connaissances et l’accès à des données thermodynamiques expérimentales dans des conditions de haute pression et de haute température sont un enjeu majeur dans l’industrie. Connaitre et anticiper le comportement d’un fluide concernant son état, sa viscosité ou encore sa densité est crucial par exemple dans le secteur de l’extraction pétrolière ou dans les procédés de transformation de la matière (raffinage, séparation, conversion,…).Ce travail de thèse s’inscrit dans ...