稀土对含钒氧化物催化裂化降硫剂结构和性能的影响

为了减少钒对降硫催化剂中裂化活性组元的破坏作用，制备了含钒和稀土金属、碱土金属的复合氧化物,采用XRD、TPR、差热、程序升温表面反应（TPSR-MS）等方法对复合氧化物的结构和噻吩类硫化物的反应机理进行研究。结果表明：镧、铈、镁分别与钒形成高熔点的LaVO4，CeVO4，MgV2O6，但第二金属元素会使氧化钒的还原温度升高，晶格氧的活性下降；在CeVO4和LaVO4上噻吩以氧化反应为主，环己烷以脱氢反应为主。为了增加噻吩的反应活性，在稀土钒酸盐中引入镁，TPSR-MS和重油微反评价结果表明，La-Mg-V上噻吩的转化率明显提高，在催化剂中加入10%La-Mg-V时，汽油硫质量分数降低了67.2%。

IMPACT OF La AND Ce ON NAPHTHA SULFUR REDUCTION OF VOx CATALYST DURING FCC PROCESS

In order to reduce the destruction impact of vanadium oxide on cracking component in FCC catalyst, the composite oxides containing vanadium, rare earth or alkaline earth metal were prepared respectively. The structures of composites were characterized by XRD, DTA, TPR and temperature-programmed surface reaction（TPSR-MS）. The mechanism of thiophenic sulfur removal was studied. The results indicate that lanthanum, cerium or Mg can react with vanadium to form a high melting point complex oxide: LaVO4, CeVO4 and MgV2O6, respectively. It is found by TPR that LaVO4 and CeVO4 can increase the reduction temperature of vanadium oxide, indicating the activity decline of the lattice oxygen. The results of TPSR-MS demonstrate that the main reaction for thiophene and cyclohexane on complex oxides (CeVO4 and LaVO4) is oxidation and dehydrogenation, respectively. TPSR-MS results show that the addition of magnesium in rare earth vanadates can significantly increase the conversion rate of thiophene. The heavy oil MAT results show that the catalyst containing 10% La-Mg-V can reduce the sulfur in naphtha by 67.2%.