煤化学链燃烧Fe2O3载氧体的反应性研究

利用流化床反应器并以水蒸气作为气化-流化介质，研究了温度、反应时间、循环数对Fe₂O₃载氧体反应性的影响。实验表明，载氧体与煤气化产物的反应性随温度升高而增强，且温度越高，反应受化学反应控制时间越短。当温度高于900℃时，煤中碳转化为CO₂的比率大于90%，载氧体体现了很好的反应性，但反应温度低于850℃时，比率小于75%。反应温度900℃时，CO₂干基浓度随循环数而逐渐降低，CO、CH₄浓度增加，且CH₄浓度值大于CO。利用XRD、SEM分析了固体反应产物成分与微观形态结构。分析表明，Fe₂O₃的还原产物为Fe₃O₄，载氧体颗粒随循环数增加而逐渐烧结。

Analysis of reactivity of Fe-based oxygen carrier with coal during chemical-looping combustion

The reactivity of using Fe₂O₃ as an oxygen carrier during chemical-looping combustion (CLC) of coal has been investigated experimentally at 800℃~950℃. The experiments were carried out in a fluidized bed, where the steam acted as the gasification fluidization medium. The reactivity of Fe₂O₃ as a function of the reactor temperature, reaction time, and cyclic reduction number was discussed. The reactivity of Fe₂O₃ oxygen carriers was enhanced as temperature increased at 800℃~950℃. Moreover, the time of chemical reaction control between the oxygen carrier and coal gasification products decreased with increased reaction temperature. When the reaction temperature was above 900℃, the rate of carbon to form CO₂ was higher than 90%; however, it was lower than 75% below 850℃. At 900℃, the dry basis concentration of CO₂ decreased with increased cyclic reduction period, while that of CO and CH₄ increased. Moreover, the value of the CO concentration was less than that of CH₄. The performance of the reacted Fe₂O₃-based oxygen carriers was also evaluated using an X-ray diffractometer and a scanning electron microscope to characterize the solid residues of oxygen carrier. The results show that Fe₂O₃-based oxygen carriers are only reduced to Fe₃O₄. With the increase of cyclic reduction period, the oxygen carrier sinters gradually.