直接球磨法制备铈基载氧体用于甲烷化学链重整制合成气性能研究

Performances of Ce-based oxygen carrier prepared by direct ball milling in chemical looping reforming of methane to syngas

采用直接球磨法和共沉淀法制备了Ce7Fe3Oδ载氧体,并用直接球磨法制备了不同Ce、Fe、Cu比例的铈铁铜载氧体,对载氧体进行H2-TPR、XRD表征。在固定床反应器中,考察了制备方法、铜掺杂量对氧载体在甲烷化学链重整制合成气中的性能的影响。结果显示,在恒温实验中,与共沉淀法相比,直接球磨法制备的Ce7Fe3Oδ载氧体有较好的反应活性,其CO选择性达到最大90%。与Ce7Fe3Oδ载氧体相比,添加铜之后复合载氧体晶格氧的释放速率、CH4转化率、CO选择性均得到提高,其中Ce7Fe3Cu0.5Oδ载氧体具有较好的反应活性。直接球磨法制备的Ce7Fe3Cu0.5Oδ载氧体经过5次循环反应后,表现出较好的反应活性和稳定性,其CO平均选择性保持在80%左右。

The oxygen carrier Ce7Fe3Oδwas prepared by direct ball milling and co-precipitation,respectively,and the Cu-dopped oxygen carriers with different ratios of Ce,Fe and Cu were prepared by direct ball milling.The oxygen carriers were characterized by H2-TPR and XRD.The effects of Cu dosage and preparation method on the performances of the oxygen carriers in looping reforming of methane to syngas were investigated in a fixed bed reactor.The results showed that the Ce7Fe3Oδprepared by the direct ball milling exhibited better activity than that prepared by co-precipitation in the isothermal experiments,where CO selectivity achieved the maximum of 90%.Compared with the Ce7Fe3Oδ,Cu dopping enhanced lattice oxygen release rate of oxygen carrier,CH4 conversion and CO selectivity,and the Ce7Fe3Cu0.5Oδexhibited optium activity.The Ce7Fe3Cu0.5Oδprepared by direct ball milling showed optium activity and stability after 5 cycles of reaction in which the average selectivity of CO kept constant at 80%roughly.