Zr0.5Ti0.5O2的添加对超临界裂解RP-3催化剂性能的影响

采用共沉淀法制备了Zr_0.5Ti_0.5O₂载体材料,将其掺杂在CeO₂-Al₂O₃ (CA)基催化剂中, 并对其催化活性进行了超临界裂解测试, 采用全自动吸附仪、X射线衍射(XRD)、透射电镜(TEM)、程序升温脱附(TPD)等方法对催化剂进行了表征. 实验结果表明, 催化剂能够明显降低裂解反应的温度, 600 ℃ CA基催化剂产气率是热裂解的2.8倍, 掺杂Zr_0.5Ti_0.5O₂载体材料的CA基催化剂是热裂解的4.0倍, 650 ℃时, 掺杂Zr_0.5Ti_0.5O₂载体材料的CA基催化剂热沉提高了0.55 MJ·kg^-1. BET结果表明, 掺杂Zr_0.5Ti_0.5O₂载体后催化剂出现双孔结构, 部分小孔的出现使得乙烯的选择性提高; NH₃-TPD结果表明, 掺杂Zr_0.5Ti_0.5O₂载体材料后, 催化剂强酸位的酸量增加了4.0倍,催化剂表现出更强的表面酸性和更集中的强酸酸中心密度, 有利于裂解多产烯烃.

Influence of Adding Zr0.5Ti0.5O2 on the Performance of Supercritical Cracking Catalyst for RP-3

Zr_0.5Ti_0.5O₂ was prepared by co-precipitation and tested for its catalytic performance under supercritical conditions when mixed with a CeO₂-Al₂O₃ (CA) base catalyst. The catalysts were characterized with an automatic adsorption instrument (BET method), X-ray diffraction (XRD), transmission electron microscopy (TEM), and temperature programmed desorption (TPD). It was found that Zr_0.5Ti_0.5O₂ significantly lowered the temperature of the cracking reaction, and increased the thermal cracking gas rate by a factor of 2.8 times as large as that at 600 ℃ for the CAbase catalyst. The gas rate was increased by a factor of 4.0 times when it was doped into the CAbase catalyst, and the heat sink increased by 0.55 MJ·kg^-1 over that of thermal cracking at 650 ℃. BET results show that the Zr_0.5Ti_0.5O₂-doped CAbase catalyst has a double-pore structure that enhances ethylene selectivity. NH3-TPD result indicates that the acidity of the catalyst increased by 4.0 times, indicating improved surface acidity conducive to alkene generation.