Bian Jiawei, Wang Bohan, Niu Ximing, Zhao Hai, Ling Hao, Ju Feng
State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
Key Laboratory of Specially Functional Polymeric Materials and Related Technology of the Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
J Hazard Mater. 2024 Jan 15;462:132778. doi: 10.1016/j.jhazmat.2023.132778. Epub 2023 Oct 13.
Fluid catalytic cracking (FCC) is the core unit for heavy oil conversion in refineries. In the FCC process, the metal contaminants from the feedstock are deposited on the catalysts, causing catalyst deactivation and metal particulate matter (PM) emission. However, the migration and emission characteristics of metal pollutants in FCC units are still unclear. Here, the stack tests of three FCC units were carried out to monitor metal PM emissions, and the metal contents of the feedstock oil and spent catalyst were detected. For the metal migration from the feedstock to the catalysts, Ni, Fe, and V have high concentrations and migration rates while other metals perform much lower. The metal distribution on the spent catalysts profoundly determines the metal mobility to the flue gas and the regeneration process affects the catalyst attrition, leading to metal PM emissions discrepancy. The migration rate and emission concentration of V in the deeper layers of the catalysts are much lower than those of Ni at the particle's exterior. Finally, the stack data was used to calculate the emission factors and ratio factors of the metal PM. This work is expected to advance metal migration cognition and metal pollutants emissions estimation in FCC units.
流化催化裂化（FCC）是炼油厂重油转化的核心装置。在FCC工艺中，原料中的金属污染物会沉积在催化剂上，导致催化剂失活并产生金属颗粒物（PM）排放。然而，FCC装置中金属污染物的迁移和排放特性仍不明确。在此，对三个FCC装置进行了烟囱测试以监测金属PM排放，并检测了原料油和废催化剂中的金属含量。对于从原料到催化剂的金属迁移，镍、铁和钒具有高浓度和迁移率，而其他金属的迁移率则低得多。废催化剂上的金属分布深刻地决定了金属向烟气中的迁移率，并且再生过程会影响催化剂磨损，从而导致金属PM排放存在差异。在催化剂较深层中钒的迁移率和排放浓度远低于颗粒外部镍的迁移率和排放浓度。最后，利用烟囱数据计算了金属PM的排放因子和比例因子。这项工作有望推进对FCC装置中金属迁移的认识以及金属污染物排放的估算。
