Combustion kinetic analysis of flame spray pyrolysis process

The flame spray pyrolysis (FSP) is a well-known process to produce nanoparticles and presents several advantages when compared to others, mainly regarding final product purity and operational flexibility. The correct modeling of the process is fundamental for the applicability of such techniques and, given that the temperature and chemical composition throughout the reactor are essential for the development of the nanoparticles, the correct representation of the chemical reactions is necessary. In this work, the production of zirconia (ZrO2) nanoparticles via FSP is modeled and the combustion of the precursor-solvent mixture is described through seven sets of different chemical reaction mechanisms to analyse their influence on flame temperature and particle evolution within the process. The reacting turbulent multiphase flow is described by an Eulerian-Lagrangian approach and ZrO2 nanoparticle growth is estimated by solving the population balance equations from a monodisperse model based on coagulation and sintering. Temperatures and primary particle diameters obtained from simulations are within 9% and 6% accuracies of experimental values, respectively. Although unmatching temperature profiles are found for the different mechanisms considered (mainly in the lower regions of the reactor), a small variation of primary particle diameter is observed when cases are compared.