Durée :3 ans

ANR ” Contacteur membranaire innovant pour la cristallisation : Application aux systèmes de type diffusion/réaction ”

Crystallization/Precipitation is one of the major unit operations of chemicals process industries to produce, purify or separate solid compounds or products. Until now, the process reference, i.e. the stirred tank reactor, stays the current crystallization process. But the need for breakthrough technologies has been highlighted by numerous authors and reports. Amongst the commonly reported technologies, membranes are one of the most promising to ensure an intensified continuous process, easy to scale-up but also to grant a fine control of the hydrodynamic and the mass/heat transfers. However, the use of microporous membranes, mainly reported in the literature, have major issues which are pores blocking by crystals, pores wetting by liquid phase and fouling, i.e. the deposit of solid compound in/on the membrane. Whatever the issue, it causes a decrease of the mass/heat transfer through the membrane inducing a decline of the process performances which are reversible or not.
To avoid pores blocking and pores wetting, the use of dense or composites membranes appear as a promising alternative. The dense membrane or the dense skin of the composite membrane has to be as finer as possible and the polymer material has to highly permeable to limit the membrane mass transfer resistance. Nevertheless, fouling stays the main issue and is currently reported on reverse osmosis membranes. In fact, intramembrane crystallization and surface deposits have been observed, depending on the type of system, but no quantitative interpretation is available. Hence, the choice of the polymer material, to a membrane processes, only considers its lower resistance to mass/heat transfer, which stays one of the most important parameter, or its hydrophobicity.
Thus, the ICARE project intends to investigate the local phenomena in order to understand and explain how, why, where and when the crystallization takes place in/on the polymer material. By the quantitative prediction of crystallization location, the aim of the ICARE project is to develop a rational knowledge of the interactions between crystals properties, operating conditions and membrane materials characteristics in order to rethink the choice of the polymer material in crystallization/precipitation membrane processes.
By choosing better the polymer material, the robustness and the life expectancy of the process membrane will be greatly improved.
But more generally, the understanding of the interactions between fluid conditions, crystals properties and membrane characteristics which constitute a breakthrough approach, could also be employed in different other application domains. Hence, in the Energy area, the choice of the polymer material used (heat exchanger or pressured retarded osmosis) reflected the same phenomenology. The same questioning could also be applied to the Water area, on the membrane used in reverse osmosis or ion exchange where fouling is almost systematically encountered. Regarding the Health fields, the benefit is completely different. Indeed, due to the comprehension of the interactions, new system of drug controlled delivery could be considered such as to inject insulin or drugs against cancer or long pain…
The potentialities will be almost unlimited. The last but not the least area which could benefit from the project is the Materials fields. By understanding how, why, where and when the solid formation takes place, in or on a polymer materials, it is possible to plan to do specific materials with the selected properties.

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