Kinetic Modelling of Thermochemical Conversion of Solid Fuels

Abstract 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).