提高延迟焦化装置运行周期的技术措施

分析了影响延迟焦化装置运行周期的主要因素,介绍了近年来装置采用的提高运行周期的技术措施,包括停止掺炼乙烯裂解重油、降低脱油沥青掺炼比例,以优化装置原料;控制好分馏塔塔底温度、小吹汽量,切塔后继续加注消泡剂和急冷油,以优化装置操作条件;阻焦剂的注入位置由加热炉入口改变至分馏塔塔底,以减缓分馏塔塔底及加热炉管结焦;焦炭塔塔顶急冷油注入方式由直接三点式注入改为环形分配器注入,以减缓大油气线及分馏塔塔底结焦。实施上述措施后,分馏塔塔底循环量由5t/h提高到20t/h,加热炉炉管压降由0.21~0.25MPa降至0.11~0.13MPa,焦炭塔塔顶压降由0.008~0.011MPa降至0.005~0.009MPa,有效地缓解了分馏塔塔底、加热炉管及大油气线的结焦,装置运行周期由开工初期的10个月提高至15个月以上,实现了长周期运行的目的。

Technical measures to improve running cycle of delayed coking unit

The main factors influencing running cycle of delayed coking unit were analyzed , and the technical measures to improve running cycle in recently years were introduced ,including no blended heavy oil from ethylene cracking and reducing the blended proportion of de-oiled as-phalt to optimize composition of feedstock ;controlling fractionator bottom temperature and steam quantity of purge of coke drum ,and prolonging injection of defoamer and quench oil after switching tower to optimize operation condition ;changing injecting position of anti-coking agent to decrease coke deposit at the bottom of fractionator and furnace tubes from furnace inlet to frac-tionator bottom ;modifying injection mode of quench oil at coke tower top to decrease coke depos-it at fractionator bottom and oil-gas lines from directly injection through three points to injection through a ring distributor .With the adoption of these measures ,the flow of circulating oil pump at fractionator bottom increased from 5 t/h to 20 t/h ,pressure drop of furnace tubes reduced from 0 .21-0 .25 MPa to 0 .11-0 .13 MPa ,pressure drop of coke tower top reduced from 0 .008-0 .011 MPa to 0 .005-0 .009 MPa ,the coking of fractionator bottom ,furnace tubes and large oil and gas line were alleviated ,the running cycle of delayed coking unit was prolonged from 10 months to 15 months and above ,and the long period operation of unit was realized .