化学链制氢中Fe_2O_3/LaFeO_3载氧体的性能研究

Performance of Fe_2O_3 /LaFeO_3 as oxygen carrier in chemical-looping hydrogen generation

采用柠檬酸络合法制备Fe2O3/LaFeO3复合氧化物,将该氧化物作为化学链制氢过程的载氧体,在反应温度为900℃、常压下,对Fe2O3/CH4(剂烷比)、进水量、金属负载量进行了考察。结果表明,剂烷比为2∶1、进水量为0.1 mL、质量分数15%Fe时载氧体性能最好,甲烷转化率达到60%,单次循环氢气产量为45 mL。将该评价结果与XRD和H2-TPR表征结果进行关联发现,反应过程的活性位不是金属氧化物,而是吸附氧,而且吸附氧越容易还原,甲烷转化率和氢气产量越高。通过连续60次还原-氧化循环发现,该载氧体上甲烷转化率和氢气产量比较稳定,循环后仍然保持钙钛矿结构。

Fe2O3 / LaFeO3 was prepared by citric acid complexation method and used as oxygen carrier in chemical-looping hydrogen generation; the effect of Fe2O3 / CH4 ratio,stream amount and metal loading on the performance of Fe2O3 / LaFeO3 as oxygen carrier at 900 ℃ and atmospheric pressure were investigated. The results showed that the oxygen carrier performs best with CH4 conversion of 60% and single-loop H2 output of 45 mL,when the ratio of Fe2O3 / CH4,stream input and Fe loading are 2,0. 1 mL,15%,respectively. The XRD and H2-TPR results suggest that the active site is the adsorbed oxygen rather than metal oxide; the easier for the reduction of the adsorbed oxygen,the higher are the conversion of CH4 and the output of H2. Moreover,the oxygen carrier is still in perovskite structure and CH4 conversion and H2 output remain stable even after 60 cycles.