催化裂化装置分馏塔结盐分析及对策  

Analysis of Salt Deposition in Fractionator of FCC Unit and Its Countermeasures

作　　者：侯和乾[1] Hou Heqian(SINOPEC Jinan Company,Jinan Shandong 250101)

机构地区：[1]中国石化济南分公司,山东济南250101

出　　处：《中外能源》2023年第9期86-91,共6页Sino-Global Energy

摘　　要：1号催化裂化装置设计规模为1.2Mt/a重油+0.88Mt/aLTAG,装置采用双反应器、双分馏塔的工艺方案。装置改造运行后分馏塔出现了几次结盐,对装置的安全平稳运行造成了一定影响。从分馏塔内盐的形成机理看,催化裂化原料中氯和氮的存在是铵盐形成的先决条件,液态水的存在是铵盐形成的充分条件。预防分馏塔结盐的措施首先是提高原油电脱盐效果,保证催化原料较低的含盐量。其次要保证分馏塔上部适宜的操作条件,在保证粗汽油质量合格的前提下,控制较高的分馏塔顶温度,适当保持冷回流量,以提高塔顶油气分压。定期对分馏塔顶循环油氯离子进行分析,结合压降变化情况综合预判系统内结盐状况。当分馏塔结盐后处理的通常方式是洗塔,而在线除盐设施的运行可较好地脱除分馏塔顶循环油中的氯离子,有效降低设备结盐腐蚀风险。The design capacity of No.1 FCC unit is 1.2Mt/a heavy oil and 0.88Mt/a LTAG,and the process scheme of double reactors and double fractionators is adopted.After the unit was modified and put into operation,salt deposition occurred several times in the fractionator,affecting the safe and stable operation of the unit.According to the formation mechanism of salt in the fractionator,the presence of chlorine and nitrogen in FCC feedstock is a prerequisite for the formation of ammonium salt,and the presence of liquid water is a sufficient condition for the formation of ammonium salt.The first measure to prevent the formation of salt in fractionator is to improve the electric desalting effect of crude oil to ensure the low salt content of FCC feedstock.Secondly,it is necessary to ensure the suitable operating conditions in the upper part of the fractionator,control a high overhead temperature of the fractionator and properly maintain the cold reflux rate while ensuring the quality of crude gasoline,so as to improve the partial pressure of oil and gas at the top of the fractionator.The chloride ion in circulating oil at the top of the fractionator is analyzed regularly,and the salt deposition in the system is predicted comprehensively based on pressure drop changes.The common method for treating the salt deposited in fractionator is to wash the tower,and the operation of online desalting facility can better remove the chloride ions in the circulating oil at the top of the fractionator,thus effectively reducing the salt corrosion risk of equipment.

关 键 词：催化裂化 分馏塔 结盐分析 除盐对策 

分 类 号：TE96[石油与天然气工程—石油机械设备]