催化裂化USY/ZnO/Al_2O_3脱硫添加剂的高温水热失活  

Hydrothermal Deactivation of USY/ZnO/Al_2O_3 Additive for Sulfur Removal of FCC Gasoline

作　　者：李春义[1] 袁起民[1] 庞新梅[2] 杨红燕[1] 山红红[1] 杨朝合[1] 张建芳[1] 

机构地区：[1]石油大学(华东)化学化工学院重质油加工国家重点实验室,山东东营257061 [2]中国石油天然气股份有限公司兰州石化公司石油化工研究院,甘肃兰州730060

出　　处：《催化学报》2003年第6期457-464,共8页

基　　金：中国石油天然气股份有限公司资助项目 ( 0 10 3 0 2 0 6)

摘　　要：对USY/ZnO/Al2 O3 汽油催化裂化脱硫添加剂经高温水热老化处理前后的脱硫性能进行了考察 ,发现老化后添加剂的脱硫性能大幅度下降 .采用XRD和IR等技术对USY/ZnO/Al2 O3 添加剂在高温和高温水热条件下失活的原因进行了研究 .结果表明 ,在高温下 ,ZnO可与USY沸石中的铝发生固相反应生成ZnAl2 O4尖晶石 ,从而造成USY晶体结构崩塌 ,转变成无定形状态 .在ZnO含量较高的条件下 ,ZnO可继续与USY晶体结构崩塌后生成的无定形的硅和铝的氧化物反应 ,生成Zn2 SiO4硅锌矿和ZnAl2 O4尖晶石结构 .这一方面使添加剂失去了可形成硫化物吸附中心的ZnO ,另一方面破坏了硫化物的裂化活性组分USY ,从而造成添加剂脱硫性能下降甚至失去脱硫活性 .ZnO对USY的破坏作用主要与温度有关 .在USY/ZnO/Al2 O3 体系中 ,ZnO被ZnO与Al2 O3 之间形成的锌铝尖晶石膜固定并与USY隔离 ,单纯的高温条件对添加剂的破坏不显著 ,而水蒸气可以促进ZnO的移动 ,有利于ZnO与USY的接触 。Using additives for sulfur removal to reduce sulfur content of FCC (fluid catalytic cracking) gasoline during the in situ FCC process is the cheapest route to desulfurization. The USY/ZnO/Al 2O 3 additive we developed can reduce more than 30% of sulfur (>400 μg/g ) in gasoline. However, the hydrothermal treatment at high temperature may cause deactivation of the additive. After the fresh additive is aged at 800 ℃ with 100% steam, the micro activity and sulfur removal activity drop significantly. In this paper, the reasons for the hydrothermal deactivation of the additive were investigated by FT IR and XRD techniques. The experiments show that hydrothermal aging at 800 ℃ with 100% steam leads to a decrease in the surface area of the additive by about 50%, the framework collapse of the cracking component USY, the disappearance of ZnO, and a drop of the Lewis and Brnsted acid amounts by 91% and 96%, respectively. These changes may be caused by the strong interactions between USY and ZnO. The experiments that USY/ZnO samples were calcined at various temperatures and then analyzed by XRD show that the destruction of USY by ZnO becomes more and more serious with increasing temperature over 650 ℃. ZnO can capture the framework Al of USY to form inert ZnAl 2O 4 spinel and cause the collapse of the framework. When the content of ZnO in the samples is enough, ZnO can react with the Si in the collapsed framework to form Zn 2SiO 4 willemite. Here, the interactions between ZnO and USY depend on temperature and seemingly have nothing to do with steam. For the USY/ZnO/Al 2O 3 additive, high temperature alone cannot cause the serious destruction of the additive. With the participation of steam, however, both USY and ZnO disappear after aging. The reason is that there is a thin layer spinel film between the ZnO particles and the support Al 2O 3, and the film can fix the ZnO particles and isolate them from the USY particles. At high temperature steam can promote the ZnO particles to break away from the bo

关 键 词：催化裂化 USY/ZnO/A12O3 脱硫 添加剂 水热失活 USY沸石 氧化锌 氧化铝 汽油 

分 类 号：TE624.9[石油与天然气工程—油气加工工程]