Numerical study on K/S/Cl release during devolatilization of pulverized biomass at high temperature

In this paper, the interaction between different organic and inorganic K/S/Cl compounds in the solid structure of biomass is studied and a model is presented to predict the temporal release of Kg, HCl, CH3Cl, KCl, KOH, K2SO4 and SO2 from biomass devolatilization. Four types of pulverized biomass are chosen from literature, two of which have no chlorine content and two with chlorine content in lower stoichiometry to potassium. The results of the model are compared with the experimental measurements. In the presence of chlorine, KCl, HCl and Kg were found to be the dominant chlorine and potassium species. In the absence of chlorine, Kg dominates the release of potassium. KOH and K2SO4 release into the gas phase towards the end of devolatilization due to the overlapping with char combustion. SO2 is the main sulfur species released into the gas phase. The model is coupled with a CFD solver where the gas phase chemistry of the K/S/Cl system can be studied using available chemical mechanisms for these species.