$NOx$ and $N2O$ Emissions During Fluidized Bed Combustion of Leather Wastes

Transformation of hide (animal skins) into leather is a complicated process during which significant amounts of wastes are generated. Fluidized bed combustion has been extended to burn different wastes that have problems with their disposal showing its technical feasibility. Considering the characteristics of the leather waste, especially the heating value $(12.5-21MJ∕kg)$⁠, it is a fairly good fuel. Moreover, leather waste has a high volatile matter, 65%, similar to other biomasses and unusual high nitrogen content, 14%. The aim of this work was to study leather wastes combustion in fluidized bed presenting experimental results regarding $NOx$ and $N2O$ emissions. A series of experiments were carried out in a fluidized bed pilot plant to understand the importance of operating parameters such as furnace temperature, oxygen content in gases, staged combustion and residence time on the $NOx$ and $N2O$ emission level. Despite having high nitrogen content, low conversion of $N$-fuel to $NOx$ and $N2O$ was measured during the combustion of leather waste in BFB. Bed temperature and oxygen content were found as the most important single parameters on $N2O$ emission and only oxygen content has a significant influence on $NOx$ emission. Leather waste exhibits a great $NOx∕O2$ trend; $NOx$ emission decreases as the oxygen concentration decreases while the effect of combustion temperature on $NOx$ is insignificant. Staged combustion does not give a reduction in $NOx$⁠.