Numerical simulations of stirred tank reactors for precipitation applications

Abstract

Co-precipitation is among the most reported methods in the literature to produce precursors for Lithium-ion battery active materials. Besides experimental results carried out from the laboratory, it is difficult to estimate the properties of such precursors. In the recent years, there is a growing interest in studying the flow fields inside a stirred tank reactor and developing a model to have an insight into Nickel-Manganese-Cobalt (NMC) particles formed through the co-precipitation of metal sulfates, notably using numerical simulations with the Computational Fluid Dynamics (CFD). This master’s thesis proposed by Umicore is dedicated to the study of the hydrodynamics and validation of a coupled Computational Fluid Dynamics-Population Balance Modelling (CFD-PBM) solver for a ten-liter stirred tank reactor configuration. The modeling framework has been developed by Politecnico di Torino to simulate numerically the co-precipitation of NMC hydroxide as the precursor of the cathode material for Li-ion batteries. The analysis is performed in the context of a six-month internship at Umicore, where CFD simulation results have mainly been obtained via the OpenFOAM environment. A study of the flow fields for the stirred tank reactor is first made. Its main goals are to define a final simulation configuration and to understand the flow behavior. The definition of this final case is achieved through mesh convergence’s and numerical methods analyses which give an insight into the choices fixed in the frame of this work. The second objective is fulfilled with a study of the numerical methods on the simulation results and of the influence of rotation speeds inside the tank. From the results obtained during this first part of the internship, the simulation solutions for precipitation applications and the role of different phenomena in the precipitates formation are then exposed and discussed. In a second step, the project aims to validate the CFD-PBM model through a complete understanding of the solver key parameters to avoid stability issues, and the modeled physics for the particles formation to reach converged results for the NMC precursors properties.