煤柴油加氢裂化装置原料反冲洗过滤器频繁冲洗原因分析及应对措施

Cause Analysis and Countermeasures for Frequent Backwashing of Raw Material Backwash Filter in Kerosene and Diesel Hydrocracking Unit

惠州石化煤柴油加氢裂化装置原料过滤器选用反冲洗过滤器,对其在第三周期运行中存在的频繁反冲洗问题进行分析和诊断,确认柔性絮状物是原料过滤器频繁反冲洗的根本原因。对相关原油进行馏分切割分析,发现絮状物主要来源于蓬莱原油的140～200℃馏分中。通过富集絮状物并用溶剂洗涤,采用红外光谱、热失重、元素分析等方法进行综合识别,确认絮状物系蓬莱原油采油过程中所加助剂四羟甲基硫酸磷(THPS)螯合氯化亚铁、钙盐,以及酰胺类高分子助剂而形成。通过采用器外超声清洗、增加过滤面积、上游避免使用四羟甲基硫酸磷助剂等应对措施,满足原料过滤器不低于8h的反冲洗时间间隔指标要求,减少了原料的反冲洗频次,不仅减少了污油产生,更确保了煤柴油加氢裂化装置的长周期、满负荷运行。

Backwash filter was selected as the raw material filter in the kerosene and diesel hydrocracking unit at CNOOC Huizhou Petrochemical Co.,Ltd.The frequent backwashing problem of the filter in the third operation cycle was analyzed and diagnosed,and it was concluded that flexible floccules are the root cause of the frequent backwashing of raw material filter.Through distillation cutting analysis of related crude oil,it was found that the floccules were mainly derived from the 140 ℃~200℃ fraction of Penglai Crude Oil.By enriching the floccules and washing them with solvents,comprehensive identification for pure floccules was carried out by infrared spectroscopy,thermogravimetric analysis,elemental analysis,etc.It was confirmed that the floccules were formed by the chelation of Tetrakis Hydroxymetyl Phosphonium Sulfuric(THPS) added during the exploitation process of Penglai Crude Oil with ferrous chloride,calcium salt and amide polymer auxiliaries.By using external ultrasonic cleaning,increasing the filtration area and avoiding the use of THPS during crude oil exploitation,the 8-hour backwashing time interval of raw material filter can be guaranteed,the frequency of raw material backwashing can be reduced,not only reducing the generation of slop oil,but also ensuring the long-term and full-load operation of the kerosene and diesel hydrocracking unit.