延迟焦化装置放空系统存在的问题及优化改造

Problems in Flare Systems of Delayed Coking Units and Countermeasures

惠州炼化4.20Mt/a延迟焦化装置放空系统在运行过程中存在放空塔入口管线开裂、放空塔冷回流空冷管束膨胀变形、放空塔顶空冷管束堵塞、放空污水油含量过高等问题。针对这些问题,进行一系列的操作改造,包括对放空塔入口管线进行应力改造、对冷回流空冷器进行结构改型、补充高温蜡油至放空塔、提高放空塔顶空冷的冷后温度、将放空塔顶分液罐分离出的轻污油回炼至分馏塔、增设放空污水除油设施等。优化改造后,放空塔入口管线再没出现过开裂的情况,空冷管束不再变形,也未出现过严重堵塞,放空污水的油含量下降70.4%,消除了影响装置安稳运行的不利因素,延长了下游酸性水汽提装置的运行周期,同时每年还能回收污油约8000t,增效约1280万元。

Some problems popped up in the flare system of CNOOC Huizhou Refining and Petrochemicals Company′ s 4.2Mt/a delayed coking unit,including cracking of the inlet line of the flare tower,expansion and deformation of the cold reflux air cooling tube bundle of the flare tower,clogging of the air cooling tube bundle at the top of the flare tower and high content of oil in the flare system sewage.A series of measures were taken to optimize the operation of the unit,including performing a stress revamp for the inlet line of the flare tower,improving the structure of the cold reflux air cooler,adding high-temperature wax oil to the flare tower,increasing the after-cooler temperature of the air cooling system at the top of the flare tower,sending the light sump oil separated from the flare scrubber at the top of the flare tower back to the frac-tionating tower for reprocessing and adding a device to remove oil in the flare system sewage.As a result of these measures,the inlet line of the flare tower has never cracked and no deformation or serious clogging of the air cooling tube bundle has ever occurred.The oil content of the flare system sewage dropped 70.4%.These measures have eliminated the adverse factors that may compromise the stable operation of the unit and extended the operational cycle of the downstream acidic water stripper.They also help the company recover around 8000 tons of sump oil annually,which is worth about 12.8 million yuan.