Population balance method in organic liquids for bubble column reactors

Bubble columns are commonly used in industry for bioprocesses, toluene hydrogenation for hydrogen transport or oligomerization of bio-ethylene... However, predicting the bubble size distribution in a bubble column under specifics operating conditions remains a major challenge for the scientific community. Indeed, the bubble size distribution depends on various parameters such as the bulk fluid properties, contamination of the gas-liquid interface, design of column… All these parameters impact coalescence and breakup mechanisms that occur at the bubble scale by modifying the physico-chemical properties of the gas-liquid system, but also the turbulence of flow. A local description of bubble breakup and coalescence phenomena is thus necessary to predict the bubble size distribution in the reactor. However, in commercial CFD codes using k- two-fluid models, only scales larger than the bubble diameter, are simulated. Breakage and coalescence phenomena require thus further effort to be modelled from local flow characteristics predicted by CFD. 
The main goal of the present proposal is to build up a breakthrough methodology based on both small and large scales experiments to determine breakage and coalescence kernels in organic liquids. Small scale experiments under controlled conditions will be performed at ICPF (Prague) to investigate breakage and coalescence phenomena. Then, bubble size distribution will be characterized in realistic bubble columns for air-water and organic systems. Two column diameters will be studied at ICPF (Prague) and at IFPEN (Lyon), to consider scale-up effects. The last stage of the PhD consists in making a link between small scale experiments under controlled conditions to the one performed in bubble columns. To do so, we will rely on breakup and coalescence kernels developed at small scale to predict the bubble size distribution and compare it to the experimental one. Kernels will be first tested using a simplified Population Balance model developed at IFPEN before being implemented in 3D two-fluid model CFD simulations.

Keywords: Bubble column, Population balance modelling, Breakup and Coalescence

• Academic supervisor    Dr Frédéric Augier, IFPEN, ORCID : 0000-0003-1640-4360
• Doctoral School    ED162 MEGA
• IFPEN supervisor    Dr Elise ALMERAS
• PhD location    IFPEN, Lyon, France (2.5 years) and ICPF, Prague, Czech Republic (6 monthes)
• Duration and start date    3 years, starting in the fourth quarter 2024 (Novembre 4)
• Employer    IFPEN
• Academic requirements    University Master degree or Engineering school in Chemical engineering/Fluid mechanics    
• Language requirements    English level B2 (CEFR)    
• Other requirements    Fondness for experiments

To apply, please send your cover letter and CV to the IFPEN supervisor indicated below.