You are welcome to attend Huabei You's MASc oral exam, in which she will discuss her research applying a multi-scale modelling framework on the NiO-based Oxygen Carrier (OC) particle in order to explicitly consider and understand the effect of reaction kinetics.
Abstract
In this work, we apply a multi-scale modelling framework on the NiO-based Oxygen Carrier (OC) particle in order to explicitly consider and understand the effect of reaction kinetics. The proposed multi-scale model consists of a gas diffusion model and a surface reaction model. Continuum equations are used to describe the gas diffusion inside OC particles, whereas Mean-field approximation and kinetic Monte Carlo methods are adopted to simulate the microscale events, such as molecule adsorption and elementary reaction, occurring on the contacting surface. These sub-models communicate through a boundary condition that defines the mass fluxes of both reactant and product gas species.
Surface reaction mechanisms and the corresponding reaction rate constants considered in the present work were obtained from a systematic Density Functional Theory (DFT) analysis. The qualitative comparison with experimental data available in the literature suggests that the kMC-based multi-scale model is able to provide better results than the MFA-based counterpart. A sensitivity analysis on the rate constants of key elementary reactions, length of intra-particle pore, and particle porosity was conducted to assess the effect of reaction kinetics and mass transport on the overall reaction process, and also to validate the proposed multi-scale model.
The simulation results show reasonable tendencies and responses to changes in these modelling parameters, which indicates that the proposed multi-scale modelling scheme on OC particle is suitable. To the author’s knowledge, this is the first implementation of a multi-scale model in CLC technology.
Supervisor: Luis Ricardez-Sandoval