The enhanced SO{sub}2 absorption capacity and kinetics due to the formation of CaSO{sub}4·3MgSO{sub}4 phase in the sulfation of calcined CMA(calcium magnesium acetate)

摘要

The sulfation rates of magnesium oxide and calcium oxide (molar ratio 7:3) contained in calcined CMA ( calcium magnesium acetate) by SO{sub}2 were measured.The experiments were carried out in the temperature range 700 to 1100°C and under the SO{sub}2 concentrations of 0.3 to 1 mol % (5 % O{sub}2). In the low-temperature range below 830°Cthe reaction produced CaSO{sub}4·3MgSO{sub}4 and unreacted MgO, but noMgSO{sub}4 phase. The formation of CaSO{sub}4·3MgSO{sub}4 phase has a significant implication in that it allows the utilization of MgO for SO{sub}2 removal whereas the sulfation of MgO from conventional sources is so slow that it is of no practicalinterest. Thus, the calcined CMA can remove SO{sub}2 at lower temperatures than conventional SO{sub}2 absorbents and at a greater capacity. Above 950°C only CaO reacts with SO{sub}2 but at a much greater rate than the calcined Ca(OH){sub}2, which is oneof the most reactive SO{sub}2 absorbents.