Identification and modeling of hydrodynamic mechanisms impacting the enzymatic hydrolysis of biomass

Biofuels as well as bio-based chemicals production represent a major transition to reduce our dependence on fossil resources. Biomass is an efficient, ecological and economically viable resource to meet both the problem of energy diversification, CO2 emissions reduction in the transportation sector, as well as to diversify chemicals formulation on the market.
These biomass conversion processes into sugars or into bioethanol involve the use of enzymes to convert polymeric sugars into monomeric sugars. This step is commonly called “enzymatic hydrolysis”. In order for this unit operation to be economically viable on a large scale, it will have to operate at high solid contents in order to process a high flow volume, produce a greater quantity of sugars and minimize separation costs by reducing water consumption in the downstream stages of the process. However, a dry matter content greater than 15%wt induces process difficulties and low sugar yields. Indeed, under these conditions, the biomass slurry shows a complex rheology with high viscosities, that complexifies the obtention of a sufficient mixing at reasonable power. 
To deal with these problems, a fundamental understanding of flow properties and their coupling with chemical reactions is mandatory. This PhD thesis aims to determine the impact of hydrodynamical parameters on solid/liquid transfers and reactions kinetics during enzymatic hydrolysis. A mixed approach of experiments and CFD simulations will allow to evidence correlations between shears, mass transfer mechanisms and reaction rates. The developed numerical model will then be applied at large scale to test different agitator configurations and guide the design of industrial reactors.

Keywords: Biomass, computational fluid dynamics, CFD, modelling, multiphase flow, stirred tanks, non-Newtonian fluid, mass transfer, reaction kinetics

• Academic supervisor    Pr. AUBIN Joelle, Laboratoire de Génie Chimique Toulouse (LGC) 
• Doctoral School    ED MEGEP, Ecole Doctorale Mécanique, Energétique, Génie Civil & Procédés Toulouse, www.univ-tlse3.fr/mecanique-energetique-genie-civil-procedes
• IFPEN supervisor    PhD. BOURAS Meriem, Chemical Engineer, Chemical Engineering and Technology Department, meriem.bouras@ifpen.fr
• PhD location    IFP Energies nouvelles, Lyon, France
• Duration and start date    3 years, starting in fourth quarter 2022
• Employer    IFP Energies nouvelles, Rueil Malmaison, France
• Academic requirements    University Master degree in Chemical Engineering
• Language requirements    Fluency in French or English, willingness to learn French
• Other requirements    Combine knowledge of computational fluid dynamics, mass transfer and reaction kinetics