Numerical investigation of the heterogeneous combustion processes of solid fuels

•Heterogeneous combustion processes of biomass in solid carbon phase are investigated.•Combustion of pulverized coal in an axisymmetric burner is studied by an Euler–Lagrange approach.•Combustion process is affected by the particulate size of solid fuels.•Optimised parametric results are found for the chemical kinetic of NOx prediction.•Numerical predicted results show very good agreement with experiment.

Two-phase computational modelling based on the Euler–Euler was developed to investigate the heterogeneous combustion processes of biomass, in the solid carbon phase, inside a newly designed combustion chamber (Model 1). A transient simulation was carried out for a small amount of carbon powder situated in a cup which was located at the centre of the combustion chamber. A heat source was provided to initiate the combustion with the air supplied by three injection nozzles. The results show that the combustion is sustained in the chamber, as evidenced by the flame temperature. An axisymmetric combustion model (Model 2) based on the Euler–Lagrange approach was formulated to model the combustion of pulverized coal. Three cases with three different char oxidation models are presented. The predicted results have good agreement with the available experimental data and showed that the combustion inside the reactor was affected by the particulate size. A number of simulations were carried out to find the best values of parameters suitable for predicting NOx pollutants.