Wang Tian, Ren Jing, Ravindra Annavarapu V, Lv Yan, Le Thiquynhxuan
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China.
Engineering Technology Research Institute of SINOPEC Catalyst Ltd., Beijing 101111, China.
Molecules. 2022 Mar 24;27(7):2078. doi: 10.3390/molecules27072078.
Ni, V and Fe are the main contaminant metals that lead to the deactivation of the spent fluid catalytic cracking (SFCC) catalyst. In this work, the properties and distribution of Ni, V and Fe in the SFCC catalyst are investigated by employing EPMA-EDX, SEM and XPS techniques. The kinetics of Ni, V, Fe and Al leaching in organic and inorganic acids are studied under microwave heating. The EPMA-EDX results show that Fe and Ni mainly accumulate near the particle surface, while V eventually distributes throughout the catalyst particle. The XPS result suggests that the phase speciations of Ni in the SFCC catalyst are Ni, Ni2SiO4 and NiAl2O4, while Fe is present in a mixture of Fe3O4, Fe2O3 and Fe2SiO4. V is in the forms of V2O5 and VO2. Compared with oxalic acid, sulfuric acid has a better removal effect of contaminant metals, especially for Ni. The leaching kinetics results indicate that using either sulfuric acid or oxalic acid, the apparent activation energy of V is obviously lower than that of Fe and Ni, and the priority of the three contaminant metals in the removal effect is V > Fe > Ni. In addition, the leaching kinetics of contaminant metals in the microwave-assisted acid activation process are controlled by the surface chemical reaction control model.
镍、钒和铁是导致催化裂化废催化剂失活的主要污染金属。在本工作中，采用电子探针微区分析-能谱仪（EPMA-EDX）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）技术研究了催化裂化废催化剂中镍、钒和铁的性质及分布。在微波加热条件下研究了镍、钒、铁和铝在有机和无机酸中的浸出动力学。EPMA-EDX结果表明，铁和镍主要积聚在颗粒表面附近，而钒最终分布在整个催化剂颗粒中。XPS结果表明，催化裂化废催化剂中镍的相态为镍、硅酸镍（Ni2SiO4）和镍铝尖晶石（NiAl2O4），而铁以四氧化三铁（Fe3O4）、三氧化二铁（Fe2O3）和硅酸铁（Fe2SiO4）的混合物形式存在。钒以五氧化二钒（V2O5）和二氧化钒（VO2）的形式存在。与草酸相比，硫酸对污染金属的去除效果更好，尤其是对镍。浸出动力学结果表明，无论是使用硫酸还是草酸，钒的表观活化能明显低于铁和镍，三种污染金属在去除效果上的优先顺序为钒>铁>镍。此外，微波辅助酸活化过程中污染金属的浸出动力学受表面化学反应控制模型控制。
