溶胶凝胶法铁基载氧体的制备与反应性能研究

采用以金属醇盐和无机盐为前驱物的两种溶胶凝胶法,以Al2O3为惰性载体,制备了Fe2O3质量分数为70%的载氧体Fe2O3/Al2O3。X射线衍射分析(XRD)表明,载氧体主要成分为Fe2O3和Al2O3。X射线荧光光谱(XRF)证明,样品中Fe2O3/Al2O3含量与设计值接近;利用不同升温速率的程序升温还原(TPR-H2)测试发现,与商业氧化铁相比,溶胶凝胶法制备的载氧体反应峰向高温区移动,说明惰性载体Al2O3对反应活性的提高作用有限。利用同步热重分析仪(TGA)对载氧体进行循环周期测试,合成的载氧体较商业载氧体具有较高的传氧能力和还原反应速率,并且在循环周期内保持了良好的反应性能。说明惰性组分Al2O3通过优化载氧体物理结构,提高了反应过程热效应的稳定性,进一步加强了Fe2O3晶格氧持续、高效的反应活性。

The Preparation and Properties of Iron-based Oxygen Carrier Using Sol-Gel Method

Particles composed of 70 wt% Fe2O3,together with Al2O3 as binder,were prepared by two different kinds of sol gel methods.X-ray diffraction analysis(XRD) showed that the main components of the oxygen carriers are Fe2O3 and Al2O3.X-ray fluorescence spectrometry analysis(XRF) proved that the contents in the samples of Fe2O3/Al2O3 were close to the designed values.Temperature programmed reduction(TPR-H2) tests in different heating rates found that compared to commercial iron oxide,the reaction peak of the the sol-gel oxygen carriers moves towards higher temperature zones,which means that inert carrier Al2O3 has little effect on improving the reactivity.Both of commercial Fe2O3 and synthesis oxygen carriers(70 wt% Fe2O3/Al2O3) have been investigated in a synchronous thermal gravimetrical analysis analyzer(TGA).In the limited cycles,synthetic oxygen carriers compared with commercial oxygen carrier had a higher oxygen transfer capability and reduction rate,and maintained a good response in the cycle properties.It meant that Al2O3 had improved the stability of the thermal reaction and further strengthened the highly effective reactivity of the lattice oxygen in Fe2O3 through optimizing the physical structure of the synthesis oxygen carriers.