Chapter 8: Reaction Network Simulation and Model Reduction

Modelling and simulation of reaction networks is a challenging task that aims to decode the inherent kinetic characteristics of complex (bio)chemical reactions. In this chapter, a heterogeneous catalysis case study is adopted to elucidate the step-by-step derivation of a microkinetic model for a given reaction network. Subsequently, the use of physics- and mathematics-based network reduction strategies is exemplified to identify kinetically negligible elementary steps in the proposed mechanism. In the physics-based approach, the ratios of the fitted microkinetic rate constants are evaluated against a threshold to identify irreversible reactions, whereas in the mathematics-based approach an additional penalty term is introduced during microkinetic parameter estimation to penalise the number of active chemical pathways. Finally, the construction of traditional steady-state models for the reduced networks is also demonstrated through the application of the pseudo-steady-state hypothesis to the reaction intermediates. The underlying physical meaning of the proposed model structures and their parameters are discussed throughout to illustrate the role of kinetic model interpretability in the development of process mechanistic understanding.