Circular economy involves the re-use of waste material as renewable resource.
This requires sometimes high technology processes, because high product
purities may be required and the waste is generally a complex mixture. The
optimization of such a process therefore necessitates a good understanding of
the physico-chemical phenomena occurring during the separation steps. These
steps are often based on phase separations between an aqueous stream and
either a solvent, a vapour or a solid. Such phase equilibrium modelling is
performed using thermodynamic models.
Thermodynamic modelling of aqueous electrolyte systems is particularly
challenging because of several difficulties. The first is the complexity of
the fluids, possibly containing organic or inorganic molecular species, acids,
bases and dissolved metal ions. The presence of ionic species implies taking
into account long-range electrostatic interactions between ions in addition to
short range ones. The second complexity is related to the physical and/or
chemical equilibria occurring within the fluid. These equilibria are very
sensitive to the dielectric constant of the medium, that in turn depends on
the fluid composition, temperature and pressure. It is therefore needed to
couple reactive and physical equilibrium.
IFPEN has been working on this subject for a number of years, and has
developed an equation of state that allows predictive phase equilibrium
computations for molecular species. It has been found that the phase
equilibrium behaviour of a mixture of water, alcohol together with an acid and
a base, is extremely sensitive to ion pairing. This phenomenon can be modelled
using a chemical equilibrium approach, but this implies (1) that these new
species must be characterized and (2) that a combined chemical and physical
equilibrium must be computed. The proposed research theme will focus on the
modelling of such systems by investigating the effect of the formation of ion
pairs. Multi-component mixtures (acid, base, co-solvent and water) will be
used as test examples. New experimental data may need to be acquired.
REQUIRED EDUCATION LEVEL
Engineering: Master Degree or equivalent
Good understanding of chemical engineering thermodynamics
Good capability in computer languages (C or C++ preferred)
If not fluent, willingness to learn french
Organisation/Company: IFP Energies nouvelles (former Institut
Français du Pétrole – IFP)
Department: Thermodynamics and molecular simulation
conducting solid electrolytes which have been widely studied but their
electrolytes is to use inorganic nanoparticles.
Among the different inorganic materials available, the sulfur family
However, such materials are mostly obtained by solid state synthesis...
In this context, the objectives of the PhD are to study the behaviour of
The work will be carried out using various tools and methods from theoretical
chemistry: DFT, DFTB, molecular dynamics, static calculations, periodic...