加圧流動層燃焼における炉内脱硫性能向上

抄録

Emissions of SO_X from a 4MWth twin-bed pressurized fluidized bed combustor (PFBC) system were measured during long-term (1187 hours) operation. The PFBC consisted of two bubbling beds, A-bed and B-bed. Though both reactors were operated at the same pressure and temperature, emissions of SO₂ differed between two reactors. The limestone particles sampled from B-bed, which showed lower emission level, had more internal cracks and their particle size was smaller than those from A-bed. Basic studies of SO₂ capture and calcination were also conducted using a pressurized fixed bed reactor for eight kinds of limestone. Calcination of limestone was found to increase reactivity with SO₂ under elevated CO₂ partial pressure conditions higher than equilibrium partial pressure. Limestones with more internal cracks were found to have higher reactivity towards SO₂ absorption. The degree of crystallization measured by X-ray diffraction gave valuable information to predict reactivity and fragmentation. The difference in emission behavior between two fluidized beds is discussed in terms of crack formation and fragmentation.