催化裂化平衡剂铁含量偏高的原因分析

针对中国石化海南炼油化工有限公司重油催化裂化装置平衡剂铁含量偏高的问题，分析了平衡剂上铁的来源及分布特点，结果表明：催化剂生产过程中引入的铁（新鲜剂本身含有的铁）占比较小且该部分铁较稳定，对平衡剂性能影响较小；催化裂化原料油带入的铁（外源污染铁）是平衡剂中铁含量的主要来源。进一步分析了原油运输、原油储存、上游加工等过程对催化裂化原料油中铁含量的影响，结果表明，原油储存及上游加工过程腐蚀会产生铁，经过没有容铁能力的渣油加氢催化剂后进入尾油，以及未加氢的重油包括渣油加氢反冲洗油（罐底油）中的铁都会进入催化裂化原料油，导致催化裂化原料中的铁含量过高。由于平衡剂表面已存在的铁会堵塞催化剂孔道，因此后续污染的无机铁在催化剂上的沉积以表面沉积为主。根据分析结果，提出了降低平衡剂中铁含量的改进措施。

CAUSE ANALYSIS OF HIGH IRON CONTENT ON FCC EQUILIBRIUM CATALYST

Aiming at the problem of excessive iron content on the FCC equilibrium catalyst of Sinopec Hainan Refining & Chemical Company, the sources and distribution characteristics of the iron on the equilibrium catalyst were analyzed. The analysis showed that the iron introduced by the catalyst production process (the iron contained in the fresh catalyst) is relatively low and stable, and its impact on the performance of equilibrium catalyst is small. The iron carried by FCC feedstock (exogenous iron) is the main source for iron on the equilibrium catalyst. It is found that the exogenous iron is from the crude oil transportation, storage and the corrosion of upstream processing units. The heavy oil without hydrogenation and the backwashing oil (bottom oil) from the residue hydrogenation unit became parts of FCC feedstock, which results in too high iron content in the FCC feedstock. Based on the analysis results, the improvement measures of reducing the iron content on the equilibrium catalyst were proposed.