SIMULATION MODEL FOR MERCURY OXIDATION AND DESULFURIZATION IN FLUIDIZED BED COAL COMBUSTION PROCESSES

This study presents a simplified simulation model developed to predict mercury oxidation and desulfurization during bubbling fluidized bed (BFB) coal combustion. The model, implemented in Aspen Plus and validated against pilot-scale experimental data, focuses on homogeneous mercury oxidation and sulfur dioxide (SO₂) capture using limestone additives. Results demonstrate that the model reasonably predicts O₂, CO₂, and NO concentrations but underestimates SO₂ in both testes and overestimates CO in one test condition. Mercury oxidation is strongly influenced by coal chlorine content, with higher chlorine levels promoting increased mercury oxidation. Limestone addition reduces SO₂ emissions by approximately 15% compared to non-additive tests. The model shows acceptably consistency with experimental data, confirming its utility for predicting system behavior under varied operational conditions. Key limitations include SO₂ underestimation and the need to incorporate more detailed mechanisms for mercury capture by fly ash.