加氢裂化装置加工焦化蜡油的难点分析与对策

以国外某炼油厂1.0 Mt/a加氢裂化装置为例,对焦化蜡油与直馏蜡油的理化性质进行了对比,分析出加氢裂化装置加工焦化蜡油的难点为硫、氮、不饱和烃、芳烃及焦粉含量高,原料干点偏高且重杂质多。针对焦化蜡油加工难点提出了以下对策:尽量控制焦化蜡油干点不高于520℃;原料油和注水罐设置氮气气封;适当注入质量分数为50~100μg/g的阻垢剂;加强注水管理,优先选用加氢类汽提水、加氢裂化塔顶凝结水、除氧水等优质水源;优化设备设计与选材;设置焦化蜡油预过滤器等一系列针对性措施,有利于加氢裂化装置的长周期稳定运行。对进料中含有焦化蜡油的加氢裂化装置的设计具有一定的指导意义。

Analysis of difficulties in processing CGO in hydrocracking unit and countermeasures

Through a case study of a 1.0 MM TPY hydrocracking Unit (HCU) in an overseas refinery,the physical and chemical properties of coker gas oil are compared with those of straight-run VGO.The difficulties in processing coker gas oil (CGO) in HCU are the high contents of sulfur,nitrogen,unsaturated hydrocarbons,aromatics and coke powders as well as higher end boiling point of feedstock and higher impurities.The following countermeasures are proposed,such as:the end point of coker gas oil is controlled to be no higher than 520 ℃,the nitrogen sealing is provided for feedstock tank and water injection drum,50 ～ 100 mg/kg fouling inhibitor is injected,water injection is strictly controlled and the water from hydrocracker stripper,overhead condensate of hydrocracker tower and deaerated water are optimally selected,equipment design and material selections are optimized and filters are installed for CGO.All these are favorable for the long-term stable operation of the hydrocracking unit and provide good guidelines for the engineering design of HCU with CGO feedstocks.