Effective Sulfur Dioxide Removal by Powder-Particle Fluidized Bed Using Fine Calcined Lime Powders Reformed by Inorganic Modifiers

Abstract

Effect of inorganic additives in limestone on desulfurization efficiency of SO₂ was investigated for dry desulfurization process with powder-particle fluidized bed (PPFB). The addition of inorganic compounds such as sodium chloride and sodium carbonate enhanced the reactivity of calcined lime powder with SO₂ in the PPFB. When 2wt% Na₂CO₃ or NaCl was added into limestone, the pore structure of lime powder was changed and SO₂ removal capacity was enhanced. In particular, Na₂CO₃ addition resulted in higher SO₂ removal efficiency than NaCl. When the average residence time of gas in the bed is as short as 0.1s, the SO₂ removal efficiency reached almost 100% at 1173K and Ca/S molar ratio of 2 for 7μm sorbent powder prepared from limestone with 2wt% Na₂CO₃, while for 5.3μm untreated lime, the corresponding SO₂ removal efficiency was 70%.