The combustion of biomass is made in a two-stage process. The first stage involves converting the solid matter on the grate into gases, while the second deals with the gas phase reactions in the combustion chamber.
The fundamental elements of fuel conversion are described in theoretical and experimental work and the multistage combustion is optimized in order to reduce pollutant emissions. To do this, a calculation model is developed that illustrates the physical and chemical processes in the fuel bed and highlights the influence of conditions that effect operations such as excess primary air, water content and primary air temperature. The influence of the distribution of primary air into different zones is examined and validated through the measurements taken at test facilities.