Cours Reaction Engineering I: Non-Ideal Reactors and Bioreactors

Abstract

This course focuses on the analysis and design of non-ideal chemical reactors, where real flow behavior deviates from ideal models such as the Plug Flow Reactor (PFR) and the Continuous Stirred Tank Reactor (CSTR). To describe these deviations, the concept of Residence Time Distribution (RTD) is introduced as a key tool. RTD provides a statistical description of how long fluid elements remain inside the reactor, allowing engineers to detect flow irregularities such as dead zones, bypassing, and recirculation. It is experimentally determined using tracer techniques and mathematically described through functions like E(t), F(t), mean residence time, and variance. By combining RTD with reaction kinetics, it becomes possible to accurately predict reactor performance, including conversion and yield. The course also covers hydrodynamic modeling of real reactors using models such as tanks-in-series and axial dispersion, as well as the role of dimensionless numbers like the Péclet and Damköhler numbers. In addition, it introduces bioreactors, which are used for enzymatic and microbial processes, emphasizing mass transfer, mixing, and reaction kinetics. Key models such as Michaelis–Menten and Monod equations describe enzymatic reactions and microbial growth. The course highlights the importance of coupling reaction kinetics, mass transfer, and fluid dynamics in reactor design, showing that real reactor behavior results from the interaction of these phenomena rather than ideal assumptions.