化学链燃烧中CaSO_4复合载氧体的实验研究

Investigation into compound CaSO_4 oxygen carrier for chemical-looping combustion

采用浸渍法制备CaSO4复合载氧体,在固定床上进行甲烷化学链燃烧实验研究。探讨了还原温度、CH4含量、载氧体的颗粒粒径和质量等因素对还原反应的影响。结果表明,Ni-Fe混合添加剂显著提高CaSO4载氧体的反应活性;合适的还原温度为925℃左右;CH4含量的降低和载氧体质量的增加,将抑制积炭的发生,并获得较高气体转化率;而载氧体颗粒粒径的变化对还原反应影响较小;长时间的还原/氧化循环实验和XRD分析证明CaSO4能完全转化成CaS,CaS也能全部转化成CaSO4。

In this study chemical-looping combustion of methane with compound CaSO4 oxygen carrier prepared by impregnation method was investigated in a fixed bed reactor.The effects of reaction temperature,CH4 percent,particle size and sample mass on reduction were discussed and an appropriate condition was determined by contrastive experiments.The results show that Ni-Fe mixed additive greatly improves the reactivity of CaSO4,and the suitable reaction temperature is around 925℃.Carbon deposition is inhibited and higher gas conversion is obtained by lower CH4 percent and more sample mass.However,the sample particle size has a little effect on the reduction.The long-time reduction-oxidation test demonstrates that compound CaSO4 oxygen carrier has a higher conversion.X-ray diffraction analysis reveals that CaSO4 could be fully reduced into CaS which is also almost oxidized into CaSO4.