惰性载体Al_2O_3对Fe_2O_3及CuO氧载体煤化学链燃烧的影响

Effect of Inert Support Al_2O_3 on the Chemical Looping Combustion of Coal With Fe_2O_3 and CuO-based Oxygen Carrier

氧载体是煤化学链燃烧技术的基础,惰性载体则是其中的必要组成部分,起着重要的作用。以Al2O3作为典型惰性载体,采用热重分析仪、红外频谱仪、场发射扫描电镜和能谱分析仪以及X衍射仪,对六盘水贫煤与Fe2O3、CuO基氧载体的反应进行了详细的研究。研究发现,Al2O3的引入,使得Fe2O3、CuO基氧载体表面积增大、孔径分布更为优化,而且对氧载体与六盘水贫煤一次热解产物的反应是有利的,能够促进氧载体中更多晶格氧的传递,Fe2O3基氧载体中有更多的Fe2O3还原为低于Fe3O4价态的氧化物,而CuO基氧载体中CuO除了还原为Cu、Cu2O外,其中的CuAl2O4也有一定的反应活性,被还原为CuAlO2。与LPS煤反应时,Fe2O3深度还原产物与部分Al2O3及煤中的SiO2反应生成Fe3Al2(SiO4)3,而CuO则与Al2O3及六盘水贫煤反应生成了(Cu0.215Mg1.785)(Al4Si5O18)复合物。

Oxygen carrier（OC） is the basis for chemical looping combustion of coal and inert support is the necessary part of OC.Al2O3 was adopted as the typical inert support and the reaction of Liupanshui（LPS） coal with Fe2O3,CuO based OC was systematically investigated by various experimental means,including thermogravimetric analysis（TGA）,Fourier transform infrared spectroscopy（FTIR）,field scanning electron microscopy coupled with energy-dispersive X-ray spectrometry（FSEM-EDX） and X-ray diffraction（XRD） analysis.It was found that,the introduction of Al2O3 to Fe2O3 and CuO made the surface areas of these two OC greatly increased and the pore distribution more optimized,which benefited the primary gaseous products of LPS coal to react with Fe2O3 and CuO.Furthermore,during the reaction of LPS with these two OC,the optimized pore size distribution promoted more sufficient reaction of LPS coal with Fe2O3,and thus more Fe2O3 was reduced into lower valence oxides than Fe3O4;but for CuO based OC,their solid reduced products with LPS were Cu,Cu2O,and the real inert support CuAl2O4 present in the CuO based OC was also found to have some reactivity and be reduced to CuAlO2.Finally,Fe3Al2（SiO4）3 was identified out by the interaction of the deep reduced Fe2O3,part of Al2O3 and SiO2 for the reaction of LPS with Fe2O3 based OC,but（Cu0.215Mg1.785）（Al4Si5O18） was formed for the reaction of LPS coal with CuO based OC.