PhD position (2016-1019): Pre-design of an innovative catalytic reactor applied to the selective hydrogenation of edible oil.

Research project description :
The scope of the study is to apply monolith reactors equipped with in situ heat removal system to the selective hydrogenation of edible oils, which represents a key-step for food industry. This kind of reactor has already been tested in a previous work at LGC for the total hydrogenation of a terpene hydrocarbon, but it has to be qualified for the purpose of reaction selectivity. The specific rheological behavior of edible oils, showing dependence on temperature and also on composition, adds a degree of complexity (called “two-way coupling”) to the modelling of the involved phenomena: hydrodynamics, mass and heat transfer, and reaction. Prediction of reactor performance needs then a specific approach.

The work will be applied to the case of partial hydrogenation of sunflower oil, and will be organized in 4 key-steps:
1. Rheology and kinetics: the latter study will be performed in an autoclave reactor, using a catalyst developed by the CIRIMAT lab (Toulouse).
2. Hydrodynamics: study of oil and H2 distribution into the monolith channels with a specific system (at 100°C, sunflower oil is ~8 times as viscous as cold water); RTD study in a “cold” mock-up (no reaction) for global characterization of flow throughout the reactor; development of a phenomenological model.
3. Complete model of reactor, with two levels of complexity :
– Isothermal pre-design of the apparatus, based on global hydrodynamics (from RTD study), estimated mass transfer rate between gas and liquid, and reaction kinetics.
– Advanced modelling of the monolith reactor by solving coupled phenomena (hydrodynamics, species transport, catalytic reaction) with COMSOL® CFD software, following a multi-scale approach from the unit cell scale (bubble+slug) to the channel scale, and to the global reactor scale. This part of work will be supervised together with Prof. F. Larachi (Laval University, Québec). Interfacial phenomena will be investigated by a DNS (Direct Numerical Simulation) approach in collaboration with another department of LGC lab.
4. Reaction tests, in catalytic pilot reactor: a small-scale monolith reactor designed for hydrogenation is available at LGC; the influence on reaction yield and selectivity of key-parameters, such as fluid flow rates and temperature, will be studied; results will be compared to the model predictions.

Laboratory: LGC (http://www.lgc.cnrs.fr/)
Doctoral school: MeGeP (http://www.ed-megep.fr/home.php): Doctoral school of Mechanics, Energetics, Civil and Process Engineering