Kinetic Modelling of Thermochemical Conversion of Solid Fuels

This chapter presents the development of models for the thermochemical conversion of coal and biomass, focusing on advances in biomass modelling. Chapter 8 introduces the characteristics of solid fuels, compares pyrolysis behaviours, and outlines the molecular structure of biomass, providing a foundation for kinetic modelling. Key models discussed include the chemical percolation devolatilisation (CPD) model, char conversion kinetics (CCK) model, and the CRECK-S model. CPD and CCK models carry an increased level of phenomenological description, ideal for benchmarking fuel conversion predictions. In contrast, CRECK-S model offers balanced complexity, predictivity and seamless coupling of pyrolysis and char reactions. The CRECK-S model is chosen to be the basis of solid fuel conversion modelling in the OxySim-129 framework, and hence is the main focus of this chapter. The outcome is a comprehensive model capable of handling diverse operating conditions that can be coupled directly or indirectly to CFD simulations. Major developments include extensions for oxy-fuel char conversion, increasing details of released products, validation for biomass feedstock samples of Oxyflame (i.e. walnut shells).